Fossil

/*
** Emits the list of built-in default CSS selectors. Intended
** for use only from the /setup_skinedit page.
*/
static void skin_emit_css_defaults(){
  struct strctCssDefaults const * pCss;
  fossil_print("<h1>CSS Defaults</h1>");
  fossil_print("If a skin defines any of the following CSS selectors, "
               "that definition replaces the default, as opposed to "
               "cascading from it. ");
  fossil_print("See <a href=\"https://fossil-scm.org/fossil/"
               "doc/trunk/www/css-tricks.md\">this "
               "document</a> for more details.");
  /* To discuss: do we want to list only the default selectors or
  ** also their default values? The latter increases the size of the
  ** page considerably, but is arguably more useful. We could, of
  ** course, offer a URL param to toggle the view, but that currently

This is a "living document" - please feel free to suggest
additions via [the Fossil forum](https://fossil-scm.org/forum/).

This document is *not* an introduction to CSS - the web is
full of tutorials on that topic. It covers only the specifics
of customizing certain CSS-based behaviors in a Fossil UI. That said...

# Overriding Default Rules

One behavior of the skinning system works considerably differently
from the cascading nature of CSS: if a skin applies a CSS selector for
which Fossil has a built-in default value, Fossil elides the entire
default definition for that rule. i.e., the skin's definition is the
only one which is applied, rather than cascading the definition from
the default value.

For example, if Fossil has a default CSS rule which looks like:

```css
div.foo {
  font-size: 120%;
  margin-left: 1em;
}
```

And a skin has:

```css
div.foo {}
```

Then Fossil will *not* emit its default rule and the user's copy will
become the only definition of that CSS rule. This is different from
normal CSS cascading rules, in which the above sequence would result
in, effectively, the top set of rules being applied because the second
(empty) one does not override anything from the first.

If a skin applies a given selector more than once, or imports external
style sheets which do, those cascade following CSS's normal rules.

## Is it Really `!important`?

By and large, CSS's `!important` qualifier is not needed when
customzing Fossil's CSS. On occasion, however, particular styles may
be set directly on DOM elements when Fossil generates its HTML, and
such cases require the use of `!important` to override them.