Add options to disable comments, the forum, and autocomplete. This is
for personal boorus and potentially for safe mode. Note that disabling
the forum may cause difficulties with creating and approving BURs.
Disabling comments and the forum merely hides them from most areas,
rather than completely removing them.
Standardize font sizes and heading tags (<h1>-<h6>) to be more
consistent across the site.
Changes:
* Introduce font size CSS variables and start replacing hardcoded font
sizes with standard sizes.
* Change header tags to use only one <h1> per page. One <h1> per page is
recommended for SEO purposes. Usually this is for the page title, like
in forum threads or wiki pages.
* Standardize on <h2> for section headers in sidebars and <h3> for
smaller subsection headers. Don't use <h4>-<h6>.
* In DText, make h1-h4 headers all the same size. Standard wiki style is
to ignore h1-h3 and start at h4.
* In DText, make h4-h6 the same size as the h1-h3 tags outside of DText.
* In the tag list, change the <h1> and <h2> tag category headers to <h3>.
* Make usernames in comments and forum posts smaller. Also change the
<h4> tag for the commenter name to <div class="author-name">.
* Make the tag list, paginator, and nav menu smaller on mobile.
* Change h1#app-name-header to a#app-name-header.
* Factor out common sidebar layout template.
* Convert wiki pages and posts to use this template.
* Add data-layout attribute to <body> element indicating the current layout.
* Consolidate blacklist css in one file.
* blacklist box: fix tag colors not dimming on hover.
* blacklist box: allow middle clicking on tags to open in new tab.
* /wiki_pages: move blacklist controls to top of tag sidebar.
* /wiki_pages: fix missing "disable all" / "re-enable all" buttons.
