reference.css

/* Custom CSS for the Rust Specification. */

/*
.parenthetical class used to keep e.g. "less-than symbol (<)" from wrapping
the end parenthesis onto its own line. Use in a span between the last word and
the parenthetical. So for this example, you'd use
```less-than <span class="parenthetical">symbol (`<`)</span>```
*/
.parenthetical {
    white-space: nowrap;
}

/*
Warnings are defined using admonitions in blockquotes:

> [!WARNING]
> This is bad!

*/
main .warning blockquote {
    padding: 0px;
}

main .warning blockquote p {
    padding: 0px 20px;
    margin: 10px 0;
}

main .warning blockquote p:first-child::before {
    content: "⚠️ ";
}

.light main .warning blockquote,
.rust main .warning blockquote {
    border: 2px solid red;
    background: #ffcece;
}

.rust main .warning blockquote {
    /* overrides previous declaration */
    border-color: #961717;
}

.coal main .warning blockquote,
.navy main .warning blockquote,
.ayu main .warning blockquote {
    background: #542626;
}

/* Make the links higher contrast on dark themes */
.coal main .warning blockquote p a,
.navy main .warning blockquote p a,
.ayu main .warning blockquote p a {
    color: #80d0d0;
}

/* <kbd> tags can be used to highlight specific character elements. */
kbd {
    border: 1px solid #999;
    display: inline-block;
    border-radius: 3px;
    padding: 0 0.6ex;
    background: #eee;
    box-shadow: inset -1px -1px 0 #999;
    vertical-align: baseline;
    color: #000;
    height: 1.55em;
    font-style: normal;
    font-weight: bold;
    font-family: inherit;
    font-size: revert;
    line-height: revert;
}
kbd.optional {
    border-style: dashed;
    background: #fff;
}
var.optional {
    border-style: dashed;
}

/* <var> tags can be used for non-terminals. */
var {
    border: 1px solid #9c9;
    box-shadow: inset -1px -1px 0 #9c9;
    font-style: normal;
    display: inline-block;
    vertical-align: baseline;
    border-radius: 7px;
    padding: 0 4px;
    background: #dfd;
    margin: 2px;
}
var.type {
    box-shadow: inset -1px -1px 0 #c99;
    border-color: #c99;
    background: #fdd;
}

/* <span class="repeat"> can be used for a grammar production that repeats zero or more times. */
span.repeat {
    position: relative;
    border: 1px dashed #393;
    border-radius: 10px;
    display: inline-block;
    padding: 6px;
    margin-left: 0.5ex;
    margin-top: 1em;
    margin-bottom: 0.5ex;
    min-width: 3.8em;
    text-align: center;
}
span.repeat::before {
    content: "zero or more";
    white-space: nowrap;
    display: block;
    text-align: center;
    font-size: 0.75em;
    position: absolute;
    left: 0;
    right: 0;
    top: -1.4em;
    color: #393;
}
var > span {
    display: inline-block;
    border-right: 1px dotted green;
    padding-right: 0.5ex;
    margin-right: 0.5ex;
    font-style: italic;
}

/* <span class="version"> can be used to highlight a specific version of Rust. */
span.version {
    float: right;
    margin-left: 1em;
    margin-bottom: 1em;
    background: #f7c0eb;
    padding: 0.2ex 0.5ex;
    border-radius: 5px;
    display: block;
    box-shadow: inset -1px -1px 0 #a06894;
    font-size: 0.9em;
}

/* <dfn> tags are used to indicate a specific word or phrase is being defined. */
dfn {
    font-style: italic;
    text-decoration: underline;
}

.content main {
    /* Provides space on the left for the rule call-outs. */
    padding-left: 4em;
}

/* Rules are generated via r[foo.bar] syntax, processed by mdbook-spec. */
.rule {
    --font-size-mult: 0.8;
    --font-size: calc(1em * var(--font-size-mult));

    font-size: var(--font-size);
}

/* included in the grid below as 20px */
.page, .content {
    padding-left: 0;
    padding-right: 0;
}
/* required to accomodate above, somehow... */
#menu-bar {
    margin-left: 0;
}

main {
    /* To nicely display rules (`[a.b.c]`) on a side of the main text body we
       use grid layout. */
    display: grid;
    grid-template-columns:
        /* Left margin / place for rules */
        [rules] minmax(20px, 1fr)
        /* The main text body */
        [text] auto
        /* Right margin */
        [margin] minmax(20px, 1fr);

    /* We do these by hand via the grid */
    margin: 0;
    padding: 0 !important;
    max-width: none !important;
}

main > * {
    /* By default grid items can't be smaller than their content.
       That is, by default `min-width: auto`.
       We want to be able to force code blocks to be scrollable,
       so we need to overwrite `min-width`. */
    min-width: 0;
    max-width: var(--content-max-width);

    /* All elements should be in the main text body... */
    grid-column: text;
}

main > .rule {
    /* ... except the rules, which must be in the left margin */
    grid-column: rules;
}

/* Unset footnote margin,
   see below for more information about margins */
/* FIXME: this doesn't work. `unset` can still break the margin of the next element,
          and since mdbook applies the margin to `:not(.footnore-definition)`,
          it can literally be anything, so there is no way to properly fix it,
          without changing mdbook... */
:not(.footnote-definition) + .footnote-definition,
.footnote-definition + :not(.footnote-definition) {
    margin-block-start: unset;
}

:not(.footnote-definition) + .footnote-definition {
     margin-top: calc(2em - 16px);
}

.footnote-definition:has(+ :not(.footnote-definition)) {
    margin-bottom: calc(2em - 16px);
}

/* This is quite dumb, ugh.
   CSS doesn't allow margin colapsing between grid items and anything else
   (src: <https://stackoverflow.com/a/37837971>), which means that the margins
   of li's children are not collapsed with ul's margins, adding too much margins.

   Ideally we'd add `<div>`s for each grid cell, so that margin collapsing happens
   as-usual inside of them. But, we don't have that kind of control over mdbook. */
main > ul > li > *:first-child,
main > ul > li > pre:first-child > pre.playground {
    margin-top: 0;
}
main > ul > li > *:last-child,
main > ul > li > pre:last-child > pre.playground {
    margin-bottom: 0;
}

/* Similarly to the above, margin collapse doesn't happen between grid items,
   so we have to replace it with grid gap. (p, pre, and ul had 16px vertical margins) */
main {
    row-gap: 16px;
}
main > p,
main > pre,
main > pre > pre.playground,
main > ul {
    margin-top: 0;
    margin-bottom: 0;
}

/* Values for header margin-top and blockquote margin are taken from mdbook's general.css,
   values for header margin-bottom are taken from <https://www.w3schools.com/cssref/css_default_values.php> */
main > h2 {
    margin-top: calc(2.5em - 16px);
    margin-bottom: calc(0.83em - 16px);
}
main > h3 {
    margin-top: calc(2.5em - 16px);
    margin-bottom: calc(1em - 16px);
}
main > h4 {
    margin-top: calc(2em - 16px);
    margin-bottom: calc(1.33em - 16px);
}
main > h5 {
    margin-top: calc(2em - 16px);
    margin-bottom: calc(1.67em - 16px);
}
main > h6 {
    margin-top: calc(2em - 16px);
    margin-bottom: calc(2.33em - 16px);
}
main > blockquote {
    margin-top: calc(20px - 16px);
    margin-bottom: calc(20px - 16px);
}

main > .rule {
    max-width: unset;
    justify-self: right;
    width: 100%;
    /* We use a container query to know the size of the "left margin",
       so that we can hide rules is there is not enough space. */
    container-type: inline-size;
    container-name: rule;
}

.rule-link {
    float: right;
    text-align: right;
    padding-right: 10px;
    /* We add `<wbr>` ourselves and only want breaks there */
    word-break: keep-all;
    /* Remove the blue coloring of links on rules that mdbook normally sets. */
    color: #999 !important;
}

/* When clicking a rule, it is added as a URL fragment and the browser will
   navigate to it. This adds an indicator that the linked rule is the one that
   is "current", just like normal headers are in mdbook.
*/
.rule:target a::before {
    display: inline-block;
    content: "»";
    padding-right: 5px;
}

/* Dodge » from headings */
.rule:has(+ h1:target),
.rule:has(+ h2:target),
.rule:has(+ h3:target),
.rule:has(+ h4:target),
.rule:has(+ h5:target),
.rule:has(+ h6:target) {
    padding-right: 24px;
}

/* Hide the rules if the width of the container is too small.
   The cutoff point is chosen semi-arbitrary, it felt that
   when `width < 14em`, there are too many breaks. */
@container rule (width < 14em) {
    main > .rule a span {
        display: none;
    }

    main > .rule a::before {
        content: "[*]";
    }
}

/* Align rules to various siblings */
.rule:has(+ p),
.rule:has(+ ul) {
    margin-top: calc((1em - var(--font-size)) / var(--font-size-mult) / 2);
}

.rule:has(+ h1) {
    align-self: center;
}

.rule:has(+ h2) {
    /* multiplying by this turns h2's em into .rule's em*/
    --h2-em-mult: calc(
        (1 / var(--font-size-mult)) /* to main font size */
          * 1.5 /* to h2 font size */
    );

    margin-top: calc(
        /* h2 margin top */
        2.5em * var(--h2-em-mult) - 16px
        /* half of the font size difference */
        + (1em * var(--h2-em-mult) - 1em) / 2
    )
}
.rule:has(+ h3) {
    /* multiplying by this turns h3's em into .rule's em*/
    --h3-em-mult: calc(
        (1 / var(--font-size-mult)) /* to main font size */
          * 1.17 /* to h3 font size */
    );

    margin-top: calc(
        /* h3 margin top */
        2.5em * var(--h3-em-mult) - 16px
        /* half of the font size difference */
        + (1em * var(--h3-em-mult) - 1em) / 2
    )
}

.rule:has(+ h4) {
    /* multiplying by this turns h4's em into .rule's em*/
    --h4-em-mult: calc(
        (1 / var(--font-size-mult)) /* to main font size */
          * 1 /* to h4 font size */
    );

    margin-top: calc(
        /* h4 margin top */
        2em * var(--h4-em-mult) - 16px
        /* half of the font size difference */
        + (1em * var(--h4-em-mult) - 1em) / 2
    )
}

.rule:has(+ h5) {
    /* multiplying by this turns h5's em into .rule's em*/
    --h5-em-mult: calc(
        (1 / var(--font-size-mult)) /* to main font size */
          * 0.83 /* to h5 font size */
    );

    margin-top: calc(
        /* h5 margin top */
        2em * var(--h5-em-mult) - 16px
        /* half of the font size difference */
        + (1em * var(--h5-em-mult) - 1em) / 2
    )
}

.rule:has(+ h6) {
    /* multiplying by this turns h6's em into .rule's em*/
    --h6-em-mult: calc(
        (1 / var(--font-size-mult)) /* to main font size */
          * 0.67 /* to h6 font size */
    );

    margin-top: calc(
        /* h6 margin top */
        2em * var(--h6-em-mult) - 16px
        /* half of the font size difference */
        + (1em * var(--h6-em-mult) - 1em) / 2
    )
}

/* Sets the color for [!HISTORY] blockquote admonitions. */
.history > blockquote {
    background: #f7c0eb;
}

/* Provides a anchor container for positioning popups. */
.popup-container {
    position: relative;
}
/* In the test summary page, a convenience class for toggling visibility. */
.popup-hidden {
    display: none;
}
/* In the test summary page, the styling for the uncovered rule popup. */
.uncovered-rules-popup {
    position: absolute;
    left: -250px;
    width: 400px;
    background: var(--bg);
    border-radius: 4px;
    border: 1px solid;
    z-index: 1000;
    padding: 1rem;
}

/* The popup that shows when viewing tests for a specific rule. */
.tests-popup {
    color: var(--fg);
    background: var(--bg);
    border-radius: 4px;
    border: 1px solid;
    z-index: 1000;
    padding: 1rem;
}