two version of R2R are hereHEADmaster

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diff --git a/.venv/lib/python3.12/site-packages/docutils/writers/_html_base.py b/.venv/lib/python3.12/site-packages/docutils/writers/_html_base.py
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+#!/usr/bin/env python3
+# :Author: David Goodger, Günter Milde
+#          Based on the html4css1 writer by David Goodger.
+# :Maintainer: docutils-develop@lists.sourceforge.net
+# :Revision: $Revision: 9614 $
+# :Date: $Date: 2005-06-28$
+# :Copyright: © 2016 David Goodger, Günter Milde
+# :License: Released under the terms of the `2-Clause BSD license`_, in short:
+#
+#    Copying and distribution of this file, with or without modification,
+#    are permitted in any medium without royalty provided the copyright
+#    notice and this notice are preserved.
+#    This file is offered as-is, without any warranty.
+#
+# .. _2-Clause BSD license: https://opensource.org/licenses/BSD-2-Clause
+
+"""common definitions for Docutils HTML writers"""
+
+import base64
+import mimetypes
+import os
+import os.path
+from pathlib import Path
+import re
+import urllib
+import warnings
+import xml.etree.ElementTree as ET  # TODO: lazy import in prepare_svg()?
+
+import docutils
+from docutils import frontend, languages, nodes, utils, writers
+from docutils.parsers.rst.directives import length_or_percentage_or_unitless
+from docutils.parsers.rst.directives.images import PIL
+from docutils.transforms import writer_aux
+from docutils.utils.math import (latex2mathml, math2html, tex2mathml_extern,
+                                 unichar2tex, wrap_math_code, MathError)
+
+
+class Writer(writers.Writer):
+
+    supported = ('html', 'xhtml')  # update in subclass
+    """Formats this writer supports."""
+
+    settings_spec = (
+        'HTML Writer Options',
+        None,
+        (('Specify the template file (UTF-8 encoded). '
+          '(default: writer dependent)',
+          ['--template'],
+          {'metavar': '<file>'}),
+         ('Comma separated list of stylesheet URLs. '
+          'Overrides previous --stylesheet and --stylesheet-path settings.',
+          ['--stylesheet'],
+          {'metavar': '<URL[,URL,...]>', 'overrides': 'stylesheet_path',
+           'validator': frontend.validate_comma_separated_list}),
+         ('Comma separated list of stylesheet paths. '
+          'Relative paths are expanded if a matching file is found in '
+          'the --stylesheet-dirs. With --link-stylesheet, '
+          'the path is rewritten relative to the output HTML file. '
+          '(default: writer dependent)',
+          ['--stylesheet-path'],
+          {'metavar': '<file[,file,...]>', 'overrides': 'stylesheet',
+           'validator': frontend.validate_comma_separated_list}),
+         ('Comma-separated list of directories where stylesheets are found. '
+          'Used by --stylesheet-path when expanding relative path arguments. '
+          '(default: writer dependent)',
+          ['--stylesheet-dirs'],
+          {'metavar': '<dir[,dir,...]>',
+           'validator': frontend.validate_comma_separated_list}),
+         ('Embed the stylesheet(s) in the output HTML file.  The stylesheet '
+          'files must be accessible during processing. (default)',
+          ['--embed-stylesheet'],
+          {'default': True, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Link to the stylesheet(s) in the output HTML file. ',
+          ['--link-stylesheet'],
+          {'dest': 'embed_stylesheet', 'action': 'store_false'}),
+         ('Specify the initial header level. '
+          'Does not affect document title & subtitle (see --no-doc-title).'
+          '(default: writer dependent).',
+          ['--initial-header-level'],
+          {'choices': '1 2 3 4 5 6'.split(), 'default': '2',
+           'metavar': '<level>'}),
+         ('Format for footnote references: one of "superscript" or '
+          '"brackets". (default: "brackets")',
+          ['--footnote-references'],
+          {'choices': ['superscript', 'brackets'], 'default': 'brackets',
+           'metavar': '<format>',
+           'overrides': 'trim_footnote_reference_space'}),
+         ('Format for block quote attributions: '
+          'one of "dash" (em-dash prefix), "parentheses"/"parens", or "none". '
+          '(default: "dash")',
+          ['--attribution'],
+          {'choices': ['dash', 'parentheses', 'parens', 'none'],
+           'default': 'dash', 'metavar': '<format>'}),
+         ('Remove extra vertical whitespace between items of "simple" bullet '
+          'lists and enumerated lists. (default)',
+          ['--compact-lists'],
+          {'default': True, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Disable compact simple bullet and enumerated lists.',
+          ['--no-compact-lists'],
+          {'dest': 'compact_lists', 'action': 'store_false'}),
+         ('Remove extra vertical whitespace between items of simple field '
+          'lists. (default)',
+          ['--compact-field-lists'],
+          {'default': True, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Disable compact simple field lists.',
+          ['--no-compact-field-lists'],
+          {'dest': 'compact_field_lists', 'action': 'store_false'}),
+         ('Added to standard table classes. '
+          'Defined styles: borderless, booktabs, '
+          'align-left, align-center, align-right, '
+          'colwidths-auto, colwidths-grid.',
+          ['--table-style'],
+          {'default': ''}),
+         ('Math output format (one of "MathML", "HTML", "MathJax", '
+          'or "LaTeX") and option(s). '
+          '(default: "HTML math.css")',
+          ['--math-output'],
+          {'default': 'HTML math.css',
+           'validator': frontend.validate_math_output}),
+         ('Prepend an XML declaration. ',
+          ['--xml-declaration'],
+          {'default': False, 'action': 'store_true',
+           'validator': frontend.validate_boolean}),
+         ('Omit the XML declaration.',
+          ['--no-xml-declaration'],
+          {'dest': 'xml_declaration', 'action': 'store_false'}),
+         ('Obfuscate email addresses to confuse harvesters while still '
+          'keeping email links usable with standards-compliant browsers.',
+          ['--cloak-email-addresses'],
+          {'action': 'store_true', 'validator': frontend.validate_boolean}),
+         )
+        )
+
+    settings_defaults = {'output_encoding_error_handler': 'xmlcharrefreplace'}
+
+    relative_path_settings = ('template',)
+
+    config_section = 'html base writer'  # overwrite in subclass
+    config_section_dependencies = ('writers', 'html writers')
+
+    visitor_attributes = (
+        'head_prefix', 'head', 'stylesheet', 'body_prefix',
+        'body_pre_docinfo', 'docinfo', 'body', 'body_suffix',
+        'title', 'subtitle', 'header', 'footer', 'meta', 'fragment',
+        'html_prolog', 'html_head', 'html_title', 'html_subtitle',
+        'html_body')
+
+    def get_transforms(self):
+        return super().get_transforms() + [writer_aux.Admonitions]
+
+    def translate(self):
+        self.visitor = visitor = self.translator_class(self.document)
+        self.document.walkabout(visitor)
+        for attr in self.visitor_attributes:
+            setattr(self, attr, getattr(visitor, attr))
+        self.output = self.apply_template()
+
+    def apply_template(self):
+        with open(self.document.settings.template, encoding='utf-8') as fp:
+            template = fp.read()
+        subs = self.interpolation_dict()
+        return template % subs
+
+    def interpolation_dict(self):
+        subs = {}
+        settings = self.document.settings
+        for attr in self.visitor_attributes:
+            subs[attr] = ''.join(getattr(self, attr)).rstrip('\n')
+        subs['encoding'] = settings.output_encoding
+        subs['version'] = docutils.__version__
+        return subs
+
+    def assemble_parts(self):
+        writers.Writer.assemble_parts(self)
+        for part in self.visitor_attributes:
+            self.parts[part] = ''.join(getattr(self, part))
+
+
+class HTMLTranslator(nodes.NodeVisitor):
+
+    """
+    Generic Docutils to HTML translator.
+
+    See the `html4css1` and `html5_polyglot` writers for full featured
+    HTML writers.
+
+    .. IMPORTANT::
+      The `visit_*` and `depart_*` methods use a
+      heterogeneous stack, `self.context`.
+      When subclassing, make sure to be consistent in its use!
+
+      Examples for robust coding:
+
+      a) Override both `visit_*` and `depart_*` methods, don't call the
+         parent functions.
+
+      b) Extend both and unconditionally call the parent functions::
+
+           def visit_example(self, node):
+               if foo:
+                   self.body.append('<div class="foo">')
+               html4css1.HTMLTranslator.visit_example(self, node)
+
+           def depart_example(self, node):
+               html4css1.HTMLTranslator.depart_example(self, node)
+               if foo:
+                   self.body.append('</div>')
+
+      c) Extend both, calling the parent functions under the same
+         conditions::
+
+           def visit_example(self, node):
+               if foo:
+                   self.body.append('<div class="foo">\n')
+               else: # call the parent method
+                   _html_base.HTMLTranslator.visit_example(self, node)
+
+           def depart_example(self, node):
+               if foo:
+                   self.body.append('</div>\n')
+               else: # call the parent method
+                   _html_base.HTMLTranslator.depart_example(self, node)
+
+      d) Extend one method (call the parent), but don't otherwise use the
+         `self.context` stack::
+
+           def depart_example(self, node):
+               _html_base.HTMLTranslator.depart_example(self, node)
+               if foo:
+                   # implementation-specific code
+                   # that does not use `self.context`
+                   self.body.append('</div>\n')
+
+      This way, changes in stack use will not bite you.
+    """
+
+    doctype = '<!DOCTYPE html>\n'
+    doctype_mathml = doctype
+
+    head_prefix_template = ('<html xmlns="http://www.w3.org/1999/xhtml"'
+                            ' xml:lang="%(lang)s" lang="%(lang)s">\n<head>\n')
+    content_type = '<meta charset="%s" />\n'
+    generator = (
+        f'<meta name="generator" content="Docutils {docutils.__version__}: '
+        'https://docutils.sourceforge.io/" />\n')
+    # `starttag()` arguments for the main document (HTML5 uses <main>)
+    documenttag_args = {'tagname': 'div', 'CLASS': 'document'}
+
+    # Template for the MathJax script in the header:
+    mathjax_script = '<script type="text/javascript" src="%s"></script>\n'
+
+    mathjax_url = 'file:/usr/share/javascript/mathjax/MathJax.js'
+    """
+    URL of the MathJax javascript library.
+
+    The MathJax library ought to be installed on the same
+    server as the rest of the deployed site files and specified
+    in the `math-output` setting appended to "mathjax".
+    See `Docutils Configuration`__.
+
+    __ https://docutils.sourceforge.io/docs/user/config.html#math-output
+
+    The fallback tries a local MathJax installation at
+    ``/usr/share/javascript/mathjax/MathJax.js``.
+    """
+
+    stylesheet_link = '<link rel="stylesheet" href="%s" type="text/css" />\n'
+    embedded_stylesheet = '<style type="text/css">\n\n%s\n</style>\n'
+    words_and_spaces = re.compile(r'[^ \n]+| +|\n')
+    # wrap point inside word:
+    in_word_wrap_point = re.compile(r'.+\W\W.+|[-?].+')
+    lang_attribute = 'lang'  # name changes to 'xml:lang' in XHTML 1.1
+
+    special_characters = {ord('&'): '&amp;',
+                          ord('<'): '&lt;',
+                          ord('"'): '&quot;',
+                          ord('>'): '&gt;',
+                          ord('@'): '&#64;',  # may thwart address harvesters
+                          }
+    """Character references for characters with a special meaning in HTML."""
+
+    videotypes = ('video/mp4', 'video/webm', 'video/ogg')
+    """MIME types supported by the HTML5 <video> element."""
+
+    def __init__(self, document):
+        nodes.NodeVisitor.__init__(self, document)
+        # process settings
+        self.settings = settings = document.settings
+        self.language = languages.get_language(
+                            settings.language_code, document.reporter)
+        self.initial_header_level = int(settings.initial_header_level)
+        # image_loading (only defined for HTML5 writer)
+        _image_loading_default = 'link'
+        # convert legacy setting embed_images:
+        if getattr(settings, 'embed_images', None) is not None:
+            if settings.embed_images:
+                _image_loading_default = 'embed'
+            warnings.warn('The configuration setting "embed_images"\n'
+                          '  will be removed in Docutils 2.0. '
+                          f'Use "image_loading: {_image_loading_default}".',
+                          FutureWarning, stacklevel=8)
+        self.image_loading = getattr(settings,
+                                     'image_loading', _image_loading_default)
+        # backwards compatibiltiy: validate/convert programatically set strings
+        if isinstance(self.settings.math_output, str):
+            self.settings.math_output = frontend.validate_math_output(
+                                            self.settings.math_output)
+        (self.math_output,
+         self.math_options) = self.settings.math_output
+
+        # set up "parts" (cf. docs/api/publisher.html#publish-parts-details)
+        #
+        self.body = []  # equivalent to `fragment`, ≠ `html_body`
+        self.body_prefix = ['</head>\n<body>\n']  # + optional header
+        self.body_pre_docinfo = []  # document heading (title and subtitle)
+        self.body_suffix = ['</body>\n</html>\n']  # + optional footer
+        self.docinfo = []
+        self.footer = []
+        self.fragment = []  # main content of the document ("naked" body)
+        self.head = []
+        self.head_prefix = []  # everything up to and including <head>
+        self.header = []
+        self.html_body = []
+        self.html_head = [self.content_type]  # charset not interpolated
+        self.html_prolog = []
+        self.html_subtitle = []
+        self.html_title = []
+        self.meta = [self.generator]
+        self.stylesheet = [self.stylesheet_call(path)
+                           for path in utils.get_stylesheet_list(settings)]
+        self.title = []
+        self.subtitle = []
+        if settings.xml_declaration:
+            self.head_prefix.append(
+                utils.xml_declaration(settings.output_encoding))
+            self.html_prolog.append(
+                utils.xml_declaration('%s'))  # encoding not interpolated
+        if (settings.output_encoding
+            and settings.output_encoding.lower() != 'unicode'):
+            self.meta.insert(0, self.content_type % settings.output_encoding)
+
+        # bookkeeping attributes; reflect state of translator
+        #
+        self.context = []
+        """Heterogeneous stack.
+
+        Used by visit_* and depart_* functions in conjunction with the tree
+        traversal. Make sure that the pops correspond to the pushes.
+        """
+        self.section_level = 0
+        self.colspecs = []
+        self.compact_p = True
+        self.compact_simple = False
+        self.compact_field_list = False
+        self.in_docinfo = False
+        self.in_sidebar = False
+        self.in_document_title = 0  # len(self.body) or 0
+        self.in_mailto = False
+        self.author_in_authors = False  # for html4css1
+        self.math_header = []
+        self.messages = []
+        """Queue of system_message nodes (writing issues).
+
+        Call `report_messages()` in `depart_*_block()` methods to clean up!
+        """
+
+    def astext(self):
+        return ''.join(self.head_prefix + self.head
+                       + self.stylesheet + self.body_prefix
+                       + self.body_pre_docinfo + self.docinfo
+                       + self.body + self.body_suffix)
+
+    def attval(self, text,
+               whitespace=re.compile('[\n\r\t\v\f]')):
+        """Cleanse, HTML encode, and return attribute value text."""
+        encoded = self.encode(whitespace.sub(' ', text))
+        if self.in_mailto and self.settings.cloak_email_addresses:
+            # Cloak at-signs ("%40") and periods with HTML entities.
+            encoded = encoded.replace('%40', '&#37;&#52;&#48;')
+            encoded = encoded.replace('.', '&#46;')
+        return encoded
+
+    def cloak_email(self, addr):
+        """Try to hide the link text of a email link from harversters."""
+        # Surround at-signs and periods with <span> tags.  ("@" has
+        # already been encoded to "&#64;" by the `encode` method.)
+        addr = addr.replace('&#64;', '<span>&#64;</span>')
+        return addr.replace('.', '<span>&#46;</span>')
+
+    def cloak_mailto(self, uri):
+        """Try to hide a mailto: URL from harvesters."""
+        # Encode "@" using a URL octet reference (see RFC 1738).
+        # Further cloaking with HTML entities will be done in the
+        # `attval` function.
+        return uri.replace('@', '%40')
+
+    def encode(self, text):
+        """Encode special characters in `text` & return."""
+        # Use only named entities known in both XML and HTML
+        # other characters are automatically encoded "by number" if required.
+        # @@@ A codec to do these and all other HTML entities would be nice.
+        text = str(text)
+        return text.translate(self.special_characters)
+
+    def image_size(self, node):
+        # Determine the image size from the node arguments or the image file.
+        # Return a size declaration suitable as "style" argument value,
+        # e.g., ``'width: 4px; height: 2em;'``.
+        # TODO: consider feature-request #102?
+        size = [node.get('width', None), node.get('height', None)]
+        if 'scale' in node:
+            if 'width' not in node or 'height' not in node:
+                # try reading size from image file
+                reading_problems = []
+                uri = node['uri']
+                if not PIL:
+                    reading_problems.append('Requires Python Imaging Library.')
+                if mimetypes.guess_type(uri)[0] in self.videotypes:
+                    reading_problems.append('PIL cannot read video images.')
+                if not self.settings.file_insertion_enabled:
+                    reading_problems.append('Reading external files disabled.')
+                if not reading_problems:
+                    try:
+                        imagepath = self.uri2imagepath(uri)
+                        with PIL.Image.open(imagepath) as img:
+                            imgsize = img.size
+                    except (ValueError, OSError, UnicodeEncodeError) as err:
+                        reading_problems.append(str(err))
+                    else:
+                        self.settings.record_dependencies.add(
+                            imagepath.replace('\\', '/'))
+                if reading_problems:
+                    msg = ['Cannot scale image!',
+                           f'Could not get size from "{uri}":',
+                           *reading_problems]
+                    self.messages.append(self.document.reporter.warning(
+                        '\n  '.join(msg), base_node=node))
+                else:
+                    for i in range(2):
+                        size[i] = size[i] or '%dpx' % imgsize[i]
+            # scale provided/determined size values:
+            factor = float(node['scale']) / 100
+            for i in range(2):
+                if size[i]:
+                    match = re.match(r'([0-9.]+)(\S*)$', size[i])
+                    size[i] = '%s%s' % (factor * float(match.group(1)),
+                                        match.group(2))
+        size_declarations = []
+        for i, dimension in enumerate(('width', 'height')):
+            if size[i]:
+                # Interpret unitless values as pixels:
+                if re.match(r'^[0-9.]+$', size[i]):
+                    size[i] += 'px'
+                size_declarations.append(f'{dimension}: {size[i]};')
+        return ' '.join(size_declarations)
+
+    def prepare_svg(self, node, imagedata, size_declaration):
+        # Edit `imagedata` for embedding as SVG image.
+        # Use ElementTree to add node attributes.
+        # ET also removes comments and preamble code.
+        #
+        # Provisional:
+        # interface and behaviour may change without notice.
+
+        # SVG namespace
+        svg_ns = {'': 'http://www.w3.org/2000/svg',
+                  'xlink': 'http://www.w3.org/1999/xlink'}
+        # don't add SVG namespace to all elements
+        ET.register_namespace('', svg_ns[''])
+        ET.register_namespace('xlink', svg_ns['xlink'])
+        try:
+            svg = ET.fromstring(imagedata.decode('utf-8'))
+        except ET.ParseError as err:
+            self.messages.append(self.document.reporter.error(
+                f'Cannot parse SVG image "{node["uri"]}":\n  {err}',
+                base_node=node))
+            return imagedata.decode('utf-8')
+        # apply image node attributes:
+        if size_declaration:  # append to style, replacing width & height
+            declarations = [d.strip() for d in svg.get('style', '').split(';')]
+            declarations = [d for d in declarations
+                            if d
+                            and not d.startswith('width')
+                            and not d.startswith('height')]
+            svg.set('style', '; '.join(declarations+[size_declaration]))
+        if node['classes'] or 'align' in node:
+            classes = svg.get('class', '').split()
+            classes += node.get('classes', [])
+            if 'align' in node:
+                classes.append(f'align-{node["align"]}')
+            svg.set('class', ' '.join(classes))
+        if 'alt' in node and svg.find('title', svg_ns) is None:
+            svg_title = ET.Element('title')
+            svg_title.text = node['alt']
+            svg.insert(0, svg_title)
+        return ET.tostring(svg, encoding='unicode')
+
+    def stylesheet_call(self, path, adjust_path=None):
+        """Return code to reference or embed stylesheet file `path`"""
+        if adjust_path is None:
+            adjust_path = bool(self.settings.stylesheet_path)
+        if self.settings.embed_stylesheet:
+            try:
+                with open(path, encoding='utf-8') as f:
+                    content = f.read()
+            except OSError as err:
+                msg = f'Cannot embed stylesheet: {err}'
+                self.document.reporter.error(msg)
+                return '<--- %s --->\n' % msg
+            else:
+                self.settings.record_dependencies.add(path)
+            return self.embedded_stylesheet % content
+        # else link to style file:
+        if adjust_path:
+            # rewrite path relative to output (cf. config.html#stylesheet-path)
+            path = utils.relative_path(self.settings._destination, path)
+        return self.stylesheet_link % self.encode(path)
+
+    def starttag(self, node, tagname, suffix='\n', empty=False, **attributes):
+        """
+        Construct and return a start tag given a node (id & class attributes
+        are extracted), tag name, and optional attributes.
+        """
+        tagname = tagname.lower()
+        prefix = []
+        atts = {}
+        for (name, value) in attributes.items():
+            atts[name.lower()] = value
+        classes = atts.pop('classes', [])
+        languages = []
+        # unify class arguments and move language specification
+        for cls in node.get('classes', []) + atts.pop('class', '').split():
+            if cls.startswith('language-'):
+                languages.append(cls[9:])
+            elif cls.strip() and cls not in classes:
+                classes.append(cls)
+        if languages:
+            # attribute name is 'lang' in XHTML 1.0 but 'xml:lang' in 1.1
+            atts[self.lang_attribute] = languages[0]
+        # filter classes that are processed by the writer:
+        internal = ('colwidths-auto', 'colwidths-given', 'colwidths-grid')
+        if isinstance(node, nodes.table):
+            classes = [cls for cls in classes if cls not in internal]
+        if classes:
+            atts['class'] = ' '.join(classes)
+        assert 'id' not in atts
+        ids = node.get('ids', [])
+        ids.extend(atts.pop('ids', []))
+        if ids:
+            atts['id'] = ids[0]
+            for id in ids[1:]:
+                # Add empty "span" elements for additional IDs.  Note
+                # that we cannot use empty "a" elements because there
+                # may be targets inside of references, but nested "a"
+                # elements aren't allowed in XHTML (even if they do
+                # not all have a "href" attribute).
+                if empty or isinstance(node, (nodes.Sequential,
+                                              nodes.docinfo,
+                                              nodes.table)):
+                    # Insert target right in front of element.
+                    prefix.append('<span id="%s"></span>' % id)
+                else:
+                    # Non-empty tag.  Place the auxiliary <span> tag
+                    # *inside* the element, as the first child.
+                    suffix += '<span id="%s"></span>' % id
+        attlist = sorted(atts.items())
+        parts = [tagname]
+        for name, value in attlist:
+            # value=None was used for boolean attributes without
+            # value, but this isn't supported by XHTML.
+            assert value is not None
+            if isinstance(value, list):
+                values = [str(v) for v in value]
+                parts.append('%s="%s"' % (name.lower(),
+                                          self.attval(' '.join(values))))
+            else:
+                parts.append('%s="%s"' % (name.lower(),
+                                          self.attval(str(value))))
+        if empty:
+            infix = ' /'
+        else:
+            infix = ''
+        return ''.join(prefix) + '<%s%s>' % (' '.join(parts), infix) + suffix
+
+    def emptytag(self, node, tagname, suffix='\n', **attributes):
+        """Construct and return an XML-compatible empty tag."""
+        return self.starttag(node, tagname, suffix, empty=True, **attributes)
+
+    def report_messages(self, node):
+        if isinstance(node.parent, (nodes.system_message, nodes.entry)):
+            return
+        while self.messages:
+            message = self.messages.pop(0)
+            if self.settings.report_level <= message['level']:
+                message.walkabout(self)
+
+    def set_class_on_child(self, node, class_, index=0):
+        """
+        Set class `class_` on the visible child no. index of `node`.
+        Do nothing if node has fewer children than `index`.
+        """
+        children = [n for n in node if not isinstance(n, nodes.Invisible)]
+        try:
+            child = children[index]
+        except IndexError:
+            return
+        child['classes'].append(class_)
+
+    def uri2imagepath(self, uri):
+        """Get filesystem path corresponding to an URI.
+
+        The image directive expects an image URI. Some writers require the
+        corresponding image path to read the image size from the file or to
+        embed the image in the output.
+
+        Absolute URIs consider the "root_prefix" setting.
+
+        In order to work in the output document, relative image URIs relate
+        to the output directory. For access by the writer, the corresponding
+        image path must be relative to the current working directory.
+
+        Provisional: the function's location, interface and behaviour
+        may change without advance warning.
+        """
+        destination = self.settings._destination or ''
+        uri_parts = urllib.parse.urlparse(uri)
+        if uri_parts.scheme not in ('', 'file'):
+            raise ValueError('Can only read local images.')
+        imagepath = urllib.request.url2pathname(uri_parts.path)
+        if imagepath.startswith('/'):
+            root_prefix = Path(self.settings.root_prefix)
+            imagepath = (root_prefix/imagepath[1:]).as_posix()
+        elif not os.path.isabs(imagepath):  # exclude absolute Windows paths
+            destdir = os.path.abspath(os.path.dirname(destination))
+            imagepath = utils.relative_path(None,
+                                            os.path.join(destdir, imagepath))
+        return imagepath
+
+    def visit_Text(self, node):
+        text = node.astext()
+        encoded = self.encode(text)
+        if self.in_mailto and self.settings.cloak_email_addresses:
+            encoded = self.cloak_email(encoded)
+        self.body.append(encoded)
+
+    def depart_Text(self, node):
+        pass
+
+    def visit_abbreviation(self, node):
+        # @@@ implementation incomplete ("title" attribute)
+        self.body.append(self.starttag(node, 'abbr', ''))
+
+    def depart_abbreviation(self, node):
+        self.body.append('</abbr>')
+
+    def visit_acronym(self, node):
+        # @@@ implementation incomplete ("title" attribute)
+        self.body.append(self.starttag(node, 'acronym', ''))
+
+    def depart_acronym(self, node):
+        self.body.append('</acronym>')
+
+    def visit_address(self, node):
+        self.visit_docinfo_item(node, 'address', meta=False)
+        self.body.append(self.starttag(node, 'pre',
+                                       suffix='', CLASS='address'))
+
+    def depart_address(self, node):
+        self.body.append('\n</pre>\n')
+        self.depart_docinfo_item()
+
+    def visit_admonition(self, node):
+        self.body.append(self.starttag(node, 'aside', classes=['admonition']))
+
+    def depart_admonition(self, node=None):
+        self.body.append('</aside>\n')
+
+    attribution_formats = {'dash': ('\u2014', ''),
+                           'parentheses': ('(', ')'),
+                           'parens': ('(', ')'),
+                           'none': ('', '')}
+
+    def visit_attribution(self, node):
+        prefix, suffix = self.attribution_formats[self.settings.attribution]
+        self.context.append(suffix)
+        self.body.append(
+            self.starttag(node, 'p', prefix, CLASS='attribution'))
+
+    def depart_attribution(self, node):
+        self.body.append(self.context.pop() + '</p>\n')
+
+    def visit_author(self, node):
+        if not isinstance(node.parent, nodes.authors):
+            self.visit_docinfo_item(node, 'author')
+        self.body.append('<p>')
+
+    def depart_author(self, node):
+        self.body.append('</p>')
+        if isinstance(node.parent, nodes.authors):
+            self.body.append('\n')
+        else:
+            self.depart_docinfo_item()
+
+    def visit_authors(self, node):
+        self.visit_docinfo_item(node, 'authors')
+
+    def depart_authors(self, node):
+        self.depart_docinfo_item()
+
+    def visit_block_quote(self, node):
+        self.body.append(self.starttag(node, 'blockquote'))
+
+    def depart_block_quote(self, node):
+        self.body.append('</blockquote>\n')
+
+    def check_simple_list(self, node):
+        """Check for a simple list that can be rendered compactly."""
+        visitor = SimpleListChecker(self.document)
+        try:
+            node.walk(visitor)
+        except nodes.NodeFound:
+            return False
+        else:
+            return True
+
+    # Compact lists
+    # ------------
+    # Include definition lists and field lists (in addition to ordered
+    # and unordered lists) in the test if a list is "simple"  (cf. the
+    # html4css1.HTMLTranslator docstring and the SimpleListChecker class at
+    # the end of this file).
+
+    def is_compactable(self, node):
+        # explicit class arguments have precedence
+        if 'compact' in node['classes']:
+            return True
+        if 'open' in node['classes']:
+            return False
+        # check config setting:
+        if (isinstance(node, (nodes.field_list, nodes.definition_list))
+            and not self.settings.compact_field_lists):
+            return False
+        if (isinstance(node, (nodes.enumerated_list, nodes.bullet_list))
+            and not self.settings.compact_lists):
+            return False
+        # Table of Contents:
+        if 'contents' in node.parent['classes']:
+            return True
+        # check the list items:
+        return self.check_simple_list(node)
+
+    def visit_bullet_list(self, node):
+        atts = {}
+        old_compact_simple = self.compact_simple
+        self.context.append((self.compact_simple, self.compact_p))
+        self.compact_p = None
+        self.compact_simple = self.is_compactable(node)
+        if self.compact_simple and not old_compact_simple:
+            atts['class'] = 'simple'
+        self.body.append(self.starttag(node, 'ul', **atts))
+
+    def depart_bullet_list(self, node):
+        self.compact_simple, self.compact_p = self.context.pop()
+        self.body.append('</ul>\n')
+
+    def visit_caption(self, node):
+        self.body.append(self.starttag(node, 'p', '', CLASS='caption'))
+
+    def depart_caption(self, node):
+        self.body.append('</p>\n')
+
+    # Use semantic tag and DPub role (HTML4 uses a table)
+    def visit_citation(self, node):
+        # role 'doc-bibloentry' requires wrapping in an element with
+        # role 'list' and an element with role 'doc-bibliography'
+        # https://www.w3.org/TR/dpub-aria-1.0/#doc-biblioentry)
+        if not isinstance(node.previous_sibling(), type(node)):
+            self.body.append('<div role="list" class="citation-list">\n')
+        self.body.append(self.starttag(node, 'div', classes=[node.tagname],
+                                       role="doc-biblioentry"))
+
+    def depart_citation(self, node):
+        self.body.append('</div>\n')
+        if not isinstance(node.next_node(descend=False, siblings=True),
+                          type(node)):
+            self.body.append('</div>\n')
+
+    # Use DPub role (overwritten in HTML4)
+    def visit_citation_reference(self, node):
+        href = '#'
+        if 'refid' in node:
+            href += node['refid']
+        elif 'refname' in node:
+            href += self.document.nameids[node['refname']]
+        # else: # TODO system message (or already in the transform)?
+        # 'Citation reference missing.'
+        self.body.append(self.starttag(node, 'a', suffix='[', href=href,
+                                       classes=['citation-reference'],
+                                       role='doc-biblioref'))
+
+    def depart_citation_reference(self, node):
+        self.body.append(']</a>')
+
+    def visit_classifier(self, node):
+        self.body.append(self.starttag(node, 'span', '', CLASS='classifier'))
+
+    def depart_classifier(self, node):
+        self.body.append('</span>')
+        self.depart_term(node)  # close the term element after last classifier
+
+    def visit_colspec(self, node):
+        self.colspecs.append(node)
+        # "stubs" list is an attribute of the tgroup element:
+        node.parent.stubs.append(node.attributes.get('stub'))
+
+    def depart_colspec(self, node):
+        # write out <colgroup> when all colspecs are processed
+        if isinstance(node.next_node(descend=False, siblings=True),
+                      nodes.colspec):
+            return
+        if 'colwidths-auto' in node.parent.parent['classes'] or (
+            'colwidths-grid' not in self.settings.table_style
+            and 'colwidths-given' not in node.parent.parent['classes']):
+            return
+        self.body.append(self.starttag(node, 'colgroup'))
+        total_width = sum(node['colwidth'] for node in self.colspecs)
+        for node in self.colspecs:
+            colwidth = node['colwidth'] / total_width
+            self.body.append(self.emptytag(node, 'col',
+                                           style=f'width: {colwidth:.1%}'))
+        self.body.append('</colgroup>\n')
+
+    def visit_comment(self, node,
+                      sub=re.compile('-(?=-)').sub):
+        """Escape double-dashes in comment text."""
+        self.body.append('<!-- %s -->\n' % sub('- ', node.astext()))
+        # Content already processed:
+        raise nodes.SkipNode
+
+    def visit_compound(self, node):
+        self.body.append(self.starttag(node, 'div', CLASS='compound'))
+
+    def depart_compound(self, node):
+        self.body.append('</div>\n')
+
+    def visit_container(self, node):
+        self.body.append(self.starttag(node, 'div',
+                                       CLASS='docutils container'))
+
+    def depart_container(self, node):
+        self.body.append('</div>\n')
+
+    def visit_contact(self, node):
+        self.visit_docinfo_item(node, 'contact', meta=False)
+
+    def depart_contact(self, node):
+        self.depart_docinfo_item()
+
+    def visit_copyright(self, node):
+        self.visit_docinfo_item(node, 'copyright')
+
+    def depart_copyright(self, node):
+        self.depart_docinfo_item()
+
+    def visit_date(self, node):
+        self.visit_docinfo_item(node, 'date')
+
+    def depart_date(self, node):
+        self.depart_docinfo_item()
+
+    def visit_decoration(self, node):
+        pass
+
+    def depart_decoration(self, node):
+        pass
+
+    def visit_definition(self, node):
+        if 'details' not in node.parent.parent['classes']:
+            self.body.append(self.starttag(node, 'dd', ''))
+
+    def depart_definition(self, node):
+        if 'details' not in node.parent.parent['classes']:
+            self.body.append('</dd>\n')
+
+    def visit_definition_list(self, node):
+        if 'details' in node['classes']:
+            self.body.append(self.starttag(node, 'div'))
+        else:
+            classes = ['simple'] if self.is_compactable(node) else []
+            self.body.append(self.starttag(node, 'dl', classes=classes))
+
+    def depart_definition_list(self, node):
+        if 'details' in node['classes']:
+            self.body.append('</div>\n')
+        else:
+            self.body.append('</dl>\n')
+
+    # Use a "details" disclosure element if parent has "class" arg "details".
+    def visit_definition_list_item(self, node):
+        if 'details' in node.parent['classes']:
+            atts = {}
+            if "open" in node.parent['classes']:
+                atts['open'] = 'open'
+            self.body.append(self.starttag(node, 'details', **atts))
+
+    def depart_definition_list_item(self, node):
+        if 'details' in node.parent['classes']:
+            self.body.append('</details>\n')
+
+    def visit_description(self, node):
+        self.body.append(self.starttag(node, 'dd', ''))
+
+    def depart_description(self, node):
+        self.body.append('</dd>\n')
+
+    def visit_docinfo(self, node):
+        self.context.append(len(self.body))
+        classes = ['docinfo']
+        if self.is_compactable(node):
+            classes.append('simple')
+        self.body.append(self.starttag(node, 'dl', classes=classes))
+
+    def depart_docinfo(self, node):
+        self.body.append('</dl>\n')
+        start = self.context.pop()
+        self.docinfo = self.body[start:]
+        self.body = []
+
+    def visit_docinfo_item(self, node, name, meta=True):
+        if meta:
+            self.meta.append(f'<meta name="{name}" '
+                             f'content="{self.attval(node.astext())}" />\n')
+        self.body.append(f'<dt class="{name}">{self.language.labels[name]}'
+                         '<span class="colon">:</span></dt>\n')
+        self.body.append(self.starttag(node, 'dd', '', CLASS=name))
+
+    def depart_docinfo_item(self):
+        self.body.append('</dd>\n')
+
+    def visit_doctest_block(self, node):
+        self.body.append(self.starttag(node, 'pre', suffix='',
+                                       classes=['code', 'python', 'doctest']))
+
+    def depart_doctest_block(self, node):
+        self.body.append('\n</pre>\n')
+
+    def visit_document(self, node):
+        title = (node.get('title') or os.path.basename(node['source'])
+                 or 'untitled Docutils document')
+        self.head.append(f'<title>{self.encode(title)}</title>\n')
+
+    def depart_document(self, node):
+        self.head_prefix.extend([self.doctype,
+                                 self.head_prefix_template %
+                                 {'lang': self.settings.language_code}])
+        self.html_prolog.append(self.doctype)
+        self.head = self.meta[:] + self.head
+        if 'name="dcterms.' in ''.join(self.meta):
+            self.head.append('<link rel="schema.dcterms"'
+                             ' href="http://purl.org/dc/terms/"/>')
+        if self.math_header:
+            if self.math_output == 'mathjax':
+                self.head.extend(self.math_header)
+            else:
+                self.stylesheet.extend(self.math_header)
+        # skip content-type meta tag with interpolated charset value:
+        self.html_head.extend(self.head[1:])
+        self.body_prefix.append(self.starttag(node, **self.documenttag_args))
+        self.body_suffix.insert(0, f'</{self.documenttag_args["tagname"]}>\n')
+        self.fragment.extend(self.body)  # self.fragment is the "naked" body
+        self.html_body.extend(self.body_prefix[1:] + self.body_pre_docinfo
+                              + self.docinfo + self.body
+                              + self.body_suffix[:-1])
+        assert not self.context, f'len(context) = {len(self.context)}'
+
+    def visit_emphasis(self, node):
+        self.body.append(self.starttag(node, 'em', ''))
+
+    def depart_emphasis(self, node):
+        self.body.append('</em>')
+
+    def visit_entry(self, node):
+        atts = {'classes': []}
+        if isinstance(node.parent.parent, nodes.thead):
+            atts['classes'].append('head')
+        if node.parent.parent.parent.stubs[node.parent.column]:
+            # "stubs" list is an attribute of the tgroup element
+            atts['classes'].append('stub')
+        if atts['classes']:
+            tagname = 'th'
+        else:
+            tagname = 'td'
+        node.parent.column += 1
+        if 'morerows' in node:
+            atts['rowspan'] = node['morerows'] + 1
+        if 'morecols' in node:
+            atts['colspan'] = node['morecols'] + 1
+            node.parent.column += node['morecols']
+        self.body.append(self.starttag(node, tagname, '', **atts))
+        self.context.append('</%s>\n' % tagname.lower())
+
+    def depart_entry(self, node):
+        self.body.append(self.context.pop())
+
+    def visit_enumerated_list(self, node):
+        atts = {'classes': []}
+        if 'start' in node:
+            atts['start'] = node['start']
+        if 'enumtype' in node:
+            atts['classes'].append(node['enumtype'])
+        if self.is_compactable(node):
+            atts['classes'].append('simple')
+        self.body.append(self.starttag(node, 'ol', **atts))
+
+    def depart_enumerated_list(self, node):
+        self.body.append('</ol>\n')
+
+    def visit_field_list(self, node):
+        atts = {}
+        classes = node.setdefault('classes', [])
+        for i, cls in enumerate(classes):
+            if cls.startswith('field-indent-'):
+                try:
+                    indent_length = length_or_percentage_or_unitless(
+                                                        cls[13:], 'px')
+                except ValueError:
+                    break
+                atts['style'] = '--field-indent: %s;' % indent_length
+                classes.pop(i)
+                break
+        classes.append('field-list')
+        if self.is_compactable(node):
+            classes.append('simple')
+        self.body.append(self.starttag(node, 'dl', **atts))
+
+    def depart_field_list(self, node):
+        self.body.append('</dl>\n')
+
+    def visit_field(self, node):
+        # Insert children (<field_name> and <field_body>) directly.
+        # Transfer "id" attribute to the <field_name> child node.
+        for child in node:
+            if isinstance(child, nodes.field_name):
+                child['ids'].extend(node['ids'])
+
+    def depart_field(self, node):
+        pass
+
+    # as field is ignored, pass class arguments to field-name and field-body:
+    def visit_field_name(self, node):
+        self.body.append(self.starttag(node, 'dt', '',
+                                       classes=node.parent['classes']))
+
+    def depart_field_name(self, node):
+        self.body.append('<span class="colon">:</span></dt>\n')
+
+    def visit_field_body(self, node):
+        self.body.append(self.starttag(node, 'dd', '',
+                                       classes=node.parent['classes']))
+        # prevent misalignment of following content if the field is empty:
+        if not node.children:
+            self.body.append('<p></p>')
+
+    def depart_field_body(self, node):
+        self.body.append('</dd>\n')
+
+    def visit_figure(self, node):
+        atts = {'class': 'figure'}
+        if node.get('width'):
+            atts['style'] = 'width: %s' % node['width']
+        if node.get('align'):
+            atts['class'] += " align-" + node['align']
+        self.body.append(self.starttag(node, 'div', **atts))
+
+    def depart_figure(self, node):
+        self.body.append('</div>\n')
+
+    def visit_footer(self, node):
+        self.context.append(len(self.body))
+
+    def depart_footer(self, node):
+        start = self.context.pop()
+        footer = [self.starttag(node, 'div', CLASS='footer'),
+                  '<hr class="footer" />\n']
+        footer.extend(self.body[start:])
+        footer.append('\n</div>\n')
+        self.footer.extend(footer)
+        self.body_suffix[:0] = footer
+        del self.body[start:]
+
+    def visit_footnote(self, node):
+        # No native HTML element: use <aside> with ARIA role
+        # (html4css1 uses tables).
+        # Wrap groups of footnotes for easier styling.
+        label_style = self.settings.footnote_references  # brackets/superscript
+        if not isinstance(node.previous_sibling(), type(node)):
+            self.body.append(f'<aside class="footnote-list {label_style}">\n')
+        self.body.append(self.starttag(node, 'aside',
+                                       classes=[node.tagname, label_style],
+                                       role="doc-footnote"))
+
+    def depart_footnote(self, node):
+        self.body.append('</aside>\n')
+        if not isinstance(node.next_node(descend=False, siblings=True),
+                          type(node)):
+            self.body.append('</aside>\n')
+
+    def visit_footnote_reference(self, node):
+        href = '#' + node['refid']
+        classes = [self.settings.footnote_references]
+        self.body.append(self.starttag(node, 'a', suffix='', classes=classes,
+                                       role='doc-noteref', href=href))
+        self.body.append('<span class="fn-bracket">[</span>')
+
+    def depart_footnote_reference(self, node):
+        self.body.append('<span class="fn-bracket">]</span>')
+        self.body.append('</a>')
+
+    # Docutils-generated text: put section numbers in a span for CSS styling:
+    def visit_generated(self, node):
+        if 'sectnum' in node['classes']:
+            # get section number (strip trailing no-break-spaces)
+            sectnum = node.astext().rstrip(' ')
+            self.body.append('<span class="sectnum">%s </span>'
+                             % self.encode(sectnum))
+            # Content already processed:
+            raise nodes.SkipNode
+
+    def depart_generated(self, node):
+        pass
+
+    def visit_header(self, node):
+        self.context.append(len(self.body))
+
+    def depart_header(self, node):
+        start = self.context.pop()
+        header = [self.starttag(node, 'div', CLASS='header')]
+        header.extend(self.body[start:])
+        header.append('\n<hr class="header"/>\n</div>\n')
+        self.body_prefix.extend(header)
+        self.header.extend(header)
+        del self.body[start:]
+
+    def visit_image(self, node):
+        # reference/embed images (still images and videos)
+        uri = node['uri']
+        alt = node.get('alt', uri)
+        mimetype = mimetypes.guess_type(uri)[0]
+        element = ''  # the HTML element (including potential children)
+        atts = {}  # attributes for the HTML tag
+        # alignment is handled by CSS rules
+        if 'align' in node:
+            atts['class'] = 'align-%s' % node['align']
+        # set size with "style" attribute (more universal, accepts dimensions)
+        size_declaration = self.image_size(node)
+        if size_declaration:
+            atts['style'] = size_declaration
+
+        # ``:loading:`` option (embed, link, lazy), default from setting,
+        # exception: only embed videos if told via directive option
+        loading = 'link' if mimetype in self.videotypes else self.image_loading
+        loading = node.get('loading', loading)
+        if loading == 'lazy':
+            atts['loading'] = 'lazy'
+        elif loading == 'embed':
+            try:
+                imagepath = self.uri2imagepath(uri)
+                with open(imagepath, 'rb') as imagefile:
+                    imagedata = imagefile.read()
+            except (ValueError, OSError) as err:
+                self.messages.append(self.document.reporter.error(
+                    f'Cannot embed image "{uri}":\n  {err}', base_node=node))
+                # TODO: get external files with urllib.request (cf. odtwriter)?
+            else:
+                self.settings.record_dependencies.add(imagepath)
+                if mimetype == 'image/svg+xml':
+                    element = self.prepare_svg(node, imagedata,
+                                               size_declaration)
+                else:
+                    data64 = base64.b64encode(imagedata).decode()
+                    uri = f'data:{mimetype};base64,{data64}'
+
+        # No newlines around inline images (but all images may be nested
+        # in a `reference` node which is a `TextElement` instance):
+        if (not isinstance(node.parent, nodes.TextElement)
+            or isinstance(node.parent, nodes.reference)
+            and not isinstance(node.parent.parent, nodes.TextElement)):
+            suffix = '\n'
+        else:
+            suffix = ''
+
+        if mimetype in self.videotypes:
+            atts['title'] = alt
+            if 'controls' in node['classes']:
+                node['classes'].remove('controls')
+                atts['controls'] = 'controls'
+            element = (self.starttag(node, "video", suffix, src=uri, **atts)
+                       + f'<a href="{node["uri"]}">{alt}</a>{suffix}'
+                       + f'</video>{suffix}')
+        elif mimetype == 'application/x-shockwave-flash':
+            atts['type'] = mimetype
+            element = (self.starttag(node, 'object', '', data=uri, **atts)
+                       + f'{alt}</object>{suffix}')
+        elif element:  # embedded SVG, see above
+            element += suffix
+        else:
+            atts['alt'] = alt
+            element = self.emptytag(node, 'img', suffix, src=uri, **atts)
+        self.body.append(element)
+        if suffix:  # block-element
+            self.report_messages(node)
+
+    def depart_image(self, node):
+        pass
+
+    def visit_inline(self, node):
+        self.body.append(self.starttag(node, 'span', ''))
+
+    def depart_inline(self, node):
+        self.body.append('</span>')
+
+    # footnote and citation labels:
+    def visit_label(self, node):
+        self.body.append('<span class="label">')
+        self.body.append('<span class="fn-bracket">[</span>')
+        # footnote/citation backrefs:
+        if self.settings.footnote_backlinks:
+            backrefs = node.parent.get('backrefs', [])
+            if len(backrefs) == 1:
+                self.body.append('<a role="doc-backlink"'
+                                 ' href="#%s">' % backrefs[0])
+
+    def depart_label(self, node):
+        backrefs = []
+        if self.settings.footnote_backlinks:
+            backrefs = node.parent.get('backrefs', backrefs)
+        if len(backrefs) == 1:
+            self.body.append('</a>')
+        self.body.append('<span class="fn-bracket">]</span></span>\n')
+        if len(backrefs) > 1:
+            backlinks = ['<a role="doc-backlink" href="#%s">%s</a>' % (ref, i)
+                         for (i, ref) in enumerate(backrefs, 1)]
+            self.body.append('<span class="backrefs">(%s)</span>\n'
+                             % ','.join(backlinks))
+
+    def visit_legend(self, node):
+        self.body.append(self.starttag(node, 'div', CLASS='legend'))
+
+    def depart_legend(self, node):
+        self.body.append('</div>\n')
+
+    def visit_line(self, node):
+        self.body.append(self.starttag(node, 'div', suffix='', CLASS='line'))
+        if not len(node):
+            self.body.append('<br />')
+
+    def depart_line(self, node):
+        self.body.append('</div>\n')
+
+    def visit_line_block(self, node):
+        self.body.append(self.starttag(node, 'div', CLASS='line-block'))
+
+    def depart_line_block(self, node):
+        self.body.append('</div>\n')
+
+    def visit_list_item(self, node):
+        self.body.append(self.starttag(node, 'li', ''))
+
+    def depart_list_item(self, node):
+        self.body.append('</li>\n')
+
+    # inline literal
+    def visit_literal(self, node):
+        # special case: "code" role
+        classes = node['classes']
+        if 'code' in classes:
+            # filter 'code' from class arguments
+            classes.pop(classes.index('code'))
+            self.body.append(self.starttag(node, 'code', ''))
+            return
+        self.body.append(
+            self.starttag(node, 'span', '', CLASS='docutils literal'))
+        text = node.astext()
+        if not isinstance(node.parent, nodes.literal_block):
+            text = text.replace('\n', ' ')
+        # Protect text like ``--an-option`` and the regular expression
+        # ``[+]?(\d+(\.\d*)?|\.\d+)`` from bad line wrapping
+        for token in self.words_and_spaces.findall(text):
+            if token.strip() and self.in_word_wrap_point.search(token):
+                self.body.append('<span class="pre">%s</span>'
+                                 % self.encode(token))
+            else:
+                self.body.append(self.encode(token))
+        self.body.append('</span>')
+        raise nodes.SkipNode  # content already processed
+
+    def depart_literal(self, node):
+        # skipped unless literal element is from "code" role:
+        self.body.append('</code>')
+
+    def visit_literal_block(self, node):
+        self.body.append(self.starttag(node, 'pre', '', CLASS='literal-block'))
+        if 'code' in node['classes']:
+            self.body.append('<code>')
+
+    def depart_literal_block(self, node):
+        if 'code' in node['classes']:
+            self.body.append('</code>')
+        self.body.append('</pre>\n')
+
+    # Mathematics:
+    # As there is no native HTML math support, we provide alternatives
+    # for the math-output: LaTeX and MathJax simply wrap the content,
+    # HTML and MathML also convert the math_code.
+    # HTML element:
+    math_tags = {  # format: (inline, block, [class arguments])
+                 'html': ('span', 'div', ['formula']),
+                 'latex': ('tt', 'pre', ['math']),
+                 'mathjax': ('span', 'div', ['math']),
+                 'mathml': ('', 'div', []),
+                 'problematic': ('span', 'pre', ['math', 'problematic']),
+                 }
+
+    def visit_math(self, node):
+        # Also called from `visit_math_block()`:
+        is_block = isinstance(node, nodes.math_block)
+        format = self.math_output
+        math_code = node.astext().translate(unichar2tex.uni2tex_table)
+
+        # preamble code and conversion
+        if format == 'html':
+            if self.math_options and not self.math_header:
+                self.math_header = [
+                    self.stylesheet_call(utils.find_file_in_dirs(
+                        s, self.settings.stylesheet_dirs), adjust_path=True)
+                    for s in self.math_options.split(',')]
+            math2html.DocumentParameters.displaymode = is_block
+            # TODO: fix display mode in matrices and fractions
+            math_code = wrap_math_code(math_code, is_block)
+            math_code = math2html.math2html(math_code)
+        elif format == 'latex':
+            math_code = self.encode(math_code)
+        elif format == 'mathjax':
+            if not self.math_header:
+                if self.math_options:
+                    self.mathjax_url = self.math_options
+                else:
+                    self.document.reporter.warning(
+                        'No MathJax URL specified, using local fallback '
+                        '(see config.html).', base_node=node)
+                # append MathJax configuration
+                # (input LaTeX with AMS, output common HTML):
+                if '?' not in self.mathjax_url:
+                    self.mathjax_url += '?config=TeX-AMS_CHTML'
+                self.math_header = [self.mathjax_script % self.mathjax_url]
+            if is_block:
+                math_code = wrap_math_code(math_code, is_block)
+            else:
+                math_code = rf'\({math_code}\)'
+            math_code = self.encode(math_code)
+        elif format == 'mathml':
+            if 'XHTML 1' in self.doctype:
+                self.doctype = self.doctype_mathml
+                self.content_type = self.content_type_mathml
+            if self.math_options:
+                converter = getattr(tex2mathml_extern, self.math_options)
+            else:
+                converter = latex2mathml.tex2mathml
+            try:
+                math_code = converter(math_code, as_block=is_block)
+            except (MathError, OSError) as err:
+                details = getattr(err, 'details', [])
+                self.messages.append(self.document.reporter.warning(
+                    err, *details, base_node=node))
+                math_code = self.encode(node.astext())
+                if self.settings.report_level <= 2:
+                    format = 'problematic'
+                else:
+                    format = 'latex'
+                if isinstance(err, OSError):
+                    # report missing converter only once
+                    self.math_output = format
+
+        # append to document body
+        tag = self.math_tags[format][is_block]
+        suffix = '\n' if is_block else ''
+        if tag:
+            self.body.append(self.starttag(node, tag, suffix=suffix,
+                                           classes=self.math_tags[format][2]))
+        self.body.extend([math_code, suffix])
+        if tag:
+            self.body.append(f'</{tag}>{suffix}')
+        # Content already processed:
+        raise nodes.SkipChildren
+
+    def depart_math(self, node):
+        pass
+
+    def visit_math_block(self, node):
+        self.visit_math(node)
+
+    def depart_math_block(self, node):
+        self.report_messages(node)
+
+    # Meta tags: 'lang' attribute replaced by 'xml:lang' in XHTML 1.1
+    # HTML5/polyglot recommends using both
+    def visit_meta(self, node):
+        self.meta.append(self.emptytag(node, 'meta',
+                                       **node.non_default_attributes()))
+
+    def depart_meta(self, node):
+        pass
+
+    def visit_option(self, node):
+        self.body.append(self.starttag(node, 'span', '', CLASS='option'))
+
+    def depart_option(self, node):
+        self.body.append('</span>')
+        if isinstance(node.next_node(descend=False, siblings=True),
+                      nodes.option):
+            self.body.append(', ')
+
+    def visit_option_argument(self, node):
+        self.body.append(node.get('delimiter', ' '))
+        self.body.append(self.starttag(node, 'var', ''))
+
+    def depart_option_argument(self, node):
+        self.body.append('</var>')
+
+    def visit_option_group(self, node):
+        self.body.append(self.starttag(node, 'dt', ''))
+        self.body.append('<kbd>')
+
+    def depart_option_group(self, node):
+        self.body.append('</kbd></dt>\n')
+
+    def visit_option_list(self, node):
+        self.body.append(
+            self.starttag(node, 'dl', CLASS='option-list'))
+
+    def depart_option_list(self, node):
+        self.body.append('</dl>\n')
+
+    def visit_option_list_item(self, node):
+        pass
+
+    def depart_option_list_item(self, node):
+        pass
+
+    def visit_option_string(self, node):
+        pass
+
+    def depart_option_string(self, node):
+        pass
+
+    def visit_organization(self, node):
+        self.visit_docinfo_item(node, 'organization')
+
+    def depart_organization(self, node):
+        self.depart_docinfo_item()
+
+    # Do not omit <p> tags
+    # --------------------
+    #
+    # The HTML4CSS1 writer does this to "produce
+    # visually compact lists (less vertical whitespace)". This writer
+    # relies on CSS rules for visual compactness.
+    #
+    # * In XHTML 1.1, e.g., a <blockquote> element may not contain
+    #   character data, so you cannot drop the <p> tags.
+    # * Keeping simple paragraphs in the field_body enables a CSS
+    #   rule to start the field-body on a new line if the label is too long
+    # * it makes the code simpler.
+    #
+    # TODO: omit paragraph tags in simple table cells?
+
+    def visit_paragraph(self, node):
+        self.body.append(self.starttag(node, 'p', ''))
+
+    def depart_paragraph(self, node):
+        self.body.append('</p>')
+        if not (isinstance(node.parent, (nodes.list_item, nodes.entry))
+                and (len(node.parent) == 1)):
+            self.body.append('\n')
+            self.report_messages(node)
+
+    def visit_problematic(self, node):
+        if node.hasattr('refid'):
+            self.body.append('<a href="#%s">' % node['refid'])
+            self.context.append('</a>')
+        else:
+            self.context.append('')
+        self.body.append(self.starttag(node, 'span', '', CLASS='problematic'))
+
+    def depart_problematic(self, node):
+        self.body.append('</span>')
+        self.body.append(self.context.pop())
+
+    def visit_raw(self, node):
+        if 'html' in node.get('format', '').split():
+            if isinstance(node.parent, nodes.TextElement):
+                tagname = 'span'
+            else:
+                tagname = 'div'
+            if node['classes']:
+                self.body.append(self.starttag(node, tagname, suffix=''))
+            self.body.append(node.astext())
+            if node['classes']:
+                self.body.append('</%s>' % tagname)
+        # Keep non-HTML raw text out of output:
+        raise nodes.SkipNode
+
+    def visit_reference(self, node):
+        atts = {'classes': ['reference']}
+        suffix = ''
+        if 'refuri' in node:
+            atts['href'] = node['refuri']
+            if (self.settings.cloak_email_addresses
+                and atts['href'].startswith('mailto:')):
+                atts['href'] = self.cloak_mailto(atts['href'])
+                self.in_mailto = True
+            atts['classes'].append('external')
+        else:
+            assert 'refid' in node, \
+                   'References must have "refuri" or "refid" attribute.'
+            atts['href'] = '#' + node['refid']
+            atts['classes'].append('internal')
+        if len(node) == 1 and isinstance(node[0], nodes.image):
+            atts['classes'].append('image-reference')
+        if not isinstance(node.parent, nodes.TextElement):
+            suffix = '\n'
+        self.body.append(self.starttag(node, 'a', suffix, **atts))
+
+    def depart_reference(self, node):
+        self.body.append('</a>')
+        if not isinstance(node.parent, nodes.TextElement):
+            self.body.append('\n')
+        self.in_mailto = False
+
+    def visit_revision(self, node):
+        self.visit_docinfo_item(node, 'revision', meta=False)
+
+    def depart_revision(self, node):
+        self.depart_docinfo_item()
+
+    def visit_row(self, node):
+        self.body.append(self.starttag(node, 'tr', ''))
+        node.column = 0
+
+    def depart_row(self, node):
+        self.body.append('</tr>\n')
+
+    def visit_rubric(self, node):
+        self.body.append(self.starttag(node, 'p', '', CLASS='rubric'))
+
+    def depart_rubric(self, node):
+        self.body.append('</p>\n')
+
+    def visit_section(self, node):
+        self.section_level += 1
+        self.body.append(
+            self.starttag(node, 'div', CLASS='section'))
+
+    def depart_section(self, node):
+        self.section_level -= 1
+        self.body.append('</div>\n')
+
+    # TODO: use the new HTML5 element <aside>
+    def visit_sidebar(self, node):
+        self.body.append(
+            self.starttag(node, 'div', CLASS='sidebar'))
+        self.in_sidebar = True
+
+    def depart_sidebar(self, node):
+        self.body.append('</div>\n')
+        self.in_sidebar = False
+
+    def visit_status(self, node):
+        self.visit_docinfo_item(node, 'status', meta=False)
+
+    def depart_status(self, node):
+        self.depart_docinfo_item()
+
+    def visit_strong(self, node):
+        self.body.append(self.starttag(node, 'strong', ''))
+
+    def depart_strong(self, node):
+        self.body.append('</strong>')
+
+    def visit_subscript(self, node):
+        self.body.append(self.starttag(node, 'sub', ''))
+
+    def depart_subscript(self, node):
+        self.body.append('</sub>')
+
+    def visit_substitution_definition(self, node):
+        """Internal only."""
+        raise nodes.SkipNode
+
+    def visit_substitution_reference(self, node):
+        self.unimplemented_visit(node)
+
+    # h1–h6 elements must not be used to markup subheadings, subtitles,
+    # alternative titles and taglines unless intended to be the heading for a
+    # new section or subsection.
+    # -- http://www.w3.org/TR/html51/sections.html#headings-and-sections
+    def visit_subtitle(self, node):
+        if isinstance(node.parent, nodes.sidebar):
+            classes = ['sidebar-subtitle']
+        elif isinstance(node.parent, nodes.document):
+            classes = ['subtitle']
+            self.in_document_title = len(self.body) + 1
+        elif isinstance(node.parent, nodes.section):
+            classes = ['section-subtitle']
+        self.body.append(self.starttag(node, 'p', '', classes=classes))
+
+    def depart_subtitle(self, node):
+        self.body.append('</p>\n')
+        if isinstance(node.parent, nodes.document):
+            self.subtitle = self.body[self.in_document_title:-1]
+            self.in_document_title = 0
+            self.body_pre_docinfo.extend(self.body)
+            self.html_subtitle.extend(self.body)
+            del self.body[:]
+
+    def visit_superscript(self, node):
+        self.body.append(self.starttag(node, 'sup', ''))
+
+    def depart_superscript(self, node):
+        self.body.append('</sup>')
+
+    def visit_system_message(self, node):
+        self.body.append(self.starttag(node, 'aside', CLASS='system-message'))
+        self.body.append('<p class="system-message-title">')
+        backref_text = ''
+        if len(node['backrefs']):
+            backrefs = node['backrefs']
+            if len(backrefs) == 1:
+                backref_text = ('; <em><a href="#%s">backlink</a></em>'
+                                % backrefs[0])
+            else:
+                i = 1
+                backlinks = []
+                for backref in backrefs:
+                    backlinks.append('<a href="#%s">%s</a>' % (backref, i))
+                    i += 1
+                backref_text = ('; <em>backlinks: %s</em>'
+                                % ', '.join(backlinks))
+        if node.hasattr('line'):
+            line = ', line %s' % node['line']
+        else:
+            line = ''
+        self.body.append('System Message: %s/%s '
+                         '(<span class="docutils literal">%s</span>%s)%s</p>\n'
+                         % (node['type'], node['level'],
+                            self.encode(node['source']), line, backref_text))
+
+    def depart_system_message(self, node):
+        self.body.append('</aside>\n')
+
+    def visit_table(self, node):
+        atts = {'classes': self.settings.table_style.replace(',', ' ').split()}
+        if 'align' in node:
+            atts['classes'].append('align-%s' % node['align'])
+        if 'width' in node:
+            atts['style'] = 'width: %s;' % node['width']
+        tag = self.starttag(node, 'table', **atts)
+        self.body.append(tag)
+
+    def depart_table(self, node):
+        self.body.append('</table>\n')
+        self.report_messages(node)
+
+    def visit_target(self, node):
+        if ('refuri' not in node
+                and 'refid' not in node
+                and 'refname' not in node):
+            self.body.append(self.starttag(node, 'span', '', CLASS='target'))
+            self.context.append('</span>')
+        else:
+            self.context.append('')
+
+    def depart_target(self, node):
+        self.body.append(self.context.pop())
+
+    # no hard-coded vertical alignment in table body
+    def visit_tbody(self, node):
+        self.body.append(self.starttag(node, 'tbody'))
+
+    def depart_tbody(self, node):
+        self.body.append('</tbody>\n')
+
+    def visit_term(self, node):
+        if 'details' in node.parent.parent['classes']:
+            self.body.append(self.starttag(node, 'summary', suffix=''))
+        else:
+            # The parent node (definition_list_item) is omitted in HTML.
+            self.body.append(self.starttag(node, 'dt', suffix='',
+                                           classes=node.parent['classes'],
+                                           ids=node.parent['ids']))
+
+    def depart_term(self, node):
+        # Nest (optional) classifier(s) in the <dt> element
+        if node.next_node(nodes.classifier, descend=False, siblings=True):
+            return  # skip (depart_classifier() calls this function again)
+        if 'details' in node.parent.parent['classes']:
+            self.body.append('</summary>\n')
+        else:
+            self.body.append('</dt>\n')
+
+    def visit_tgroup(self, node):
+        self.colspecs = []
+        node.stubs = []
+
+    def depart_tgroup(self, node):
+        pass
+
+    def visit_thead(self, node):
+        self.body.append(self.starttag(node, 'thead'))
+
+    def depart_thead(self, node):
+        self.body.append('</thead>\n')
+
+    def section_title_tags(self, node):
+        atts = {}
+        h_level = self.section_level + self.initial_header_level - 1
+        # Only 6 heading levels have dedicated HTML tags.
+        tagname = 'h%i' % min(h_level, 6)
+        if h_level > 6:
+            atts['aria-level'] = h_level
+        start_tag = self.starttag(node, tagname, '', **atts)
+        if node.hasattr('refid'):
+            atts = {}
+            atts['class'] = 'toc-backref'
+            atts['role'] = 'doc-backlink'  # HTML5 only
+            atts['href'] = '#' + node['refid']
+            start_tag += self.starttag(nodes.reference(), 'a', '', **atts)
+            close_tag = '</a></%s>\n' % tagname
+        else:
+            close_tag = '</%s>\n' % tagname
+        return start_tag, close_tag
+
+    def visit_title(self, node):
+        close_tag = '</p>\n'
+        if isinstance(node.parent, nodes.topic):
+            # TODO: use role="heading" or <h1>? (HTML5 only)
+            self.body.append(
+                self.starttag(node, 'p', '', CLASS='topic-title'))
+            if (self.settings.toc_backlinks
+                and 'contents' in node.parent['classes']):
+                self.body.append('<a class="reference internal" href="#top">')
+                close_tag = '</a></p>\n'
+        elif isinstance(node.parent, nodes.sidebar):
+            # TODO: use role="heading" or <h1>? (HTML5 only)
+            self.body.append(
+                self.starttag(node, 'p', '', CLASS='sidebar-title'))
+        elif isinstance(node.parent, nodes.Admonition):
+            self.body.append(
+                  self.starttag(node, 'p', '', CLASS='admonition-title'))
+        elif isinstance(node.parent, nodes.table):
+            self.body.append(self.starttag(node, 'caption', ''))
+            close_tag = '</caption>\n'
+        elif isinstance(node.parent, nodes.document):
+            self.body.append(self.starttag(node, 'h1', '', CLASS='title'))
+            close_tag = '</h1>\n'
+            self.in_document_title = len(self.body)
+        else:
+            assert isinstance(node.parent, nodes.section)
+            # Get correct heading and evt. backlink tags
+            start_tag, close_tag = self.section_title_tags(node)
+            self.body.append(start_tag)
+        self.context.append(close_tag)
+
+    def depart_title(self, node):
+        self.body.append(self.context.pop())
+        if self.in_document_title:
+            self.title = self.body[self.in_document_title:-1]
+            self.in_document_title = 0
+            self.body_pre_docinfo.extend(self.body)
+            self.html_title.extend(self.body)
+            del self.body[:]
+
+    def visit_title_reference(self, node):
+        self.body.append(self.starttag(node, 'cite', ''))
+
+    def depart_title_reference(self, node):
+        self.body.append('</cite>')
+
+    def visit_topic(self, node):
+        self.body.append(self.starttag(node, 'div', CLASS='topic'))
+
+    def depart_topic(self, node):
+        self.body.append('</div>\n')
+
+    def visit_transition(self, node):
+        self.body.append(self.emptytag(node, 'hr', CLASS='docutils'))
+
+    def depart_transition(self, node):
+        pass
+
+    def visit_version(self, node):
+        self.visit_docinfo_item(node, 'version', meta=False)
+
+    def depart_version(self, node):
+        self.depart_docinfo_item()
+
+    def unimplemented_visit(self, node):
+        raise NotImplementedError('visiting unimplemented node type: %s'
+                                  % node.__class__.__name__)
+
+
+class SimpleListChecker(nodes.GenericNodeVisitor):
+
+    """
+    Raise `nodes.NodeFound` if non-simple list item is encountered.
+
+    Here "simple" means a list item containing nothing other than a single
+    paragraph, a simple list, or a paragraph followed by a simple list.
+
+    This version also checks for simple field lists and docinfo.
+    """
+
+    def default_visit(self, node):
+        raise nodes.NodeFound
+
+    def visit_list_item(self, node):
+        children = [child for child in node.children
+                    if not isinstance(child, nodes.Invisible)]
+        if (children and isinstance(children[0], nodes.paragraph)
+            and (isinstance(children[-1], nodes.bullet_list)
+                 or isinstance(children[-1], nodes.enumerated_list)
+                 or isinstance(children[-1], nodes.field_list))):
+            children.pop()
+        if len(children) <= 1:
+            return
+        else:
+            raise nodes.NodeFound
+
+    def pass_node(self, node):
+        pass
+
+    def ignore_node(self, node):
+        # ignore nodes that are never complex (can contain only inline nodes)
+        raise nodes.SkipNode
+
+    # Paragraphs and text
+    visit_Text = ignore_node
+    visit_paragraph = ignore_node
+
+    # Lists
+    visit_bullet_list = pass_node
+    visit_enumerated_list = pass_node
+    visit_docinfo = pass_node
+
+    # Docinfo nodes:
+    visit_author = ignore_node
+    visit_authors = visit_list_item
+    visit_address = visit_list_item
+    visit_contact = pass_node
+    visit_copyright = ignore_node
+    visit_date = ignore_node
+    visit_organization = ignore_node
+    visit_status = ignore_node
+    visit_version = visit_list_item
+
+    # Definition list:
+    visit_definition_list = pass_node
+    visit_definition_list_item = pass_node
+    visit_term = ignore_node
+    visit_classifier = pass_node
+    visit_definition = visit_list_item
+
+    # Field list:
+    visit_field_list = pass_node
+    visit_field = pass_node
+    # the field body corresponds to a list item
+    visit_field_body = visit_list_item
+    visit_field_name = ignore_node
+
+    # Invisible nodes should be ignored.
+    visit_comment = ignore_node
+    visit_substitution_definition = ignore_node
+    visit_target = ignore_node
+    visit_pending = ignore_node