presentations/highlight-js/docs/style-guide.rst

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Style guide
===========
Key principle
-------------
Highlight.js themes are language agnostic.
Instead of trying to make a *rich* set of highlightable classes look good in a
handful of languages we have a *limited* set of classes that work for all
languages.
Hence, there are two important implications:
* Highlight.js styles tend to be minimalistic.
* It's not possible to exactly emulate themes from other highlighting engines.
Defining a theme
----------------
A theme is a single CSS defining styles for class names listed in the
:doc:`class reference </css-classes-reference>`. The general guideline is to
style all available classes, however an author may deliberately choose to
exclude some (for example, ``.attr`` is usually left unstyled).
You are not required to invent a separate styling for every group of class
names, it's perfectly okay to group them:
::
.hljs-string,
.hljs-section,
.hljs-selector-class,
.hljs-template-variable,
.hljs-deletion {
color: #800;
}
Use as few or as many unique style combinations as you want.
Typography and layout dos and don'ts
------------------------------------
Don't use:
* non-standard borders/margin/paddings for the root container ``.hljs``
* specific font faces
* font size, line height and anything that affects position and size of
characters within the container
Okay to use:
* colors (obviously!)
* italic, bold, underlining, etc.
* image backgrounds
These may seem arbitrary at first but it's what has shown to make sense in
practice.
There's also a common set of rules that *has* to be defined for the root
container verbatim:
::
.hljs {
display: block;
overflow-x: auto;
padding: 0.5em;
}
``.subst``
----------
One important caveat: don't forget to style ``.subst``. It's used for parsed
sections within strings and almost always should be reset to the default color:
::
.hljs,
.hljs-subst {
color: black;
}
Contributing
------------
You should include a comment at the top of the CSS file with attribution and
other meta data if necessary. The format is free:
::
/*
Fancy style (c) John Smith <email@domain.com>
*/
If you're a new contributor add yourself to the authors list in AUTHORS.en.txt
Also update CHANGES.md with your contribution.
Send your contribution as a pull request on GitHub.