:root {
    --color-background: #303030;
    --color-text: #c6c6c6;
    --color-surface: #585858;
    --color-border: #ababab;
    --color-accent: cornflowerblue;
    --color-link-visited: cadetblue;
    --color-code: #ffed29;
    --color-ids-text: #a0f0a0;
    --color-highlight: aqua;
    --color-credit-border: green;
}

* {
    font-family: Inter, example, "Source Han Sans CN", IDC, Plgo1, Plgo2;
    font-style: normal;
    font-variant-numeric: tabular-nums;
}

.invert-dark-mode {
    filter: invert(100%);
}

body {
    background-color: var(--color-background);
    line-height: 1.75;
    color: var(--color-text);
    max-width: 70em;
    padding: 1em;
    margin: auto;
    position: relative;

    &:has(input#toggle-light-mode:checked) {
        --color-background: #F8F8F8;
        --color-text: #101010;
        --color-surface: #e8e8e8;
        --color-border: #ababab;
        --color-accent: #0000EE;
        --color-link-visited: #551A8B;
        --color-code: #cd8500;
        --color-ids-text: darkgreen;
        --color-highlight: darkred;
        --color-credit-border: darkgreen;

        .invert-dark-mode {
            filter: invert(0%);
        }
    }
}

h1 {
    font:
        1000 2.5em "Source Han Serif",
        serif;
    margin: 1em 0 0 0;
    padding: 5px;
    text-align: center;
    line-height: 1.2;
}
subtitle {
    display: block;
    font-size: 0.9em;
    text-align: center;
}

h2 {
    font-weight: 800;
    font-size: 1.7rem;
    margin: 1em 0 8px;
    padding: 6px 6px 6px 0.5em;
    border-top: solid 2px var(--color-accent);
    border-left: solid 2px var(--color-accent);
}

h3 {
    font-weight: 700;
    font-size: 1.5rem;
    margin: 0.5em 0 8px;
    padding: 5px;
    border-bottom: solid 1px var(--color-border);
    width: fit-content;
}

h4 {
    font-weight: 600;
    font-size: 1.2rem;
    margin: 0.5em 0 0 0;
    padding: 5px;
}

h5 {
    font-weight: 500;
    font-size: 1.1rem;
    margin: 0.5em 0 0 0;
    padding: 5px;
}

p {
    text-indent: 2em;
    margin: 0;
}
u {
    text-underline-offset: 6px;
}

em {
    text-emphasis: filled circle;
    text-emphasis-position: under;

    &[lang="en"] {
        text-emphasis: none;
        font-style: italic;
    }
}

pre,
code {
    color: var(--color-code);
    background-color: var(--color-surface);
    padding: 2px 4px;
    border-radius: 5px;
    overflow-x: auto;
}
pre {
    padding: 8px;
    overflow-x: auto;
    & > code {
        padding: 0;
    }
}

a {
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

a:link {
    color: var(--color-accent);
}

a:visited {
    color: var(--color-link-visited);
}

ul {
    margin-block: 6px;
}

.toc {
    line-height: 1.25;
}

.toc ul,
.toc ul ul,
.toc ul ul ul,
.toc ul ul ul ul {
    list-style-type: none;
    padding-left: 1em;
}

.toc li {
    margin-bottom: 10px;
}

.toc ul ul li {
    margin-bottom: 5px;
}

.toc ul ul ul li {
    margin-bottom: 2px;
}

.toc ul ul ul ul li {
    margin-bottom: 0;
}

table {
    width: fit-content;
    max-width: 100%;
    margin: auto;
    margin-top: 8px;
    border-collapse: collapse;
    overflow-x: auto;
}

th {
    background-color: var(--color-surface);
}

th,
td {
    padding: 5px;
    border: solid 1px var(--color-border);
    text-align: center;
}

@font-face {
    font-family: "Plgo1";
    src: url("fonts/Plgo1.woff2") format("woff2");
    font-display: swap;
    unicode-range: U+2????;
}
@font-face {
    font-family: "Plgo2";
    src: url("fonts/Plgo2.woff2") format("woff2");
    font-display: swap;
    unicode-range: U+30000-323AF;
}

@font-face {
    font-family: "SM-SC";
    src: url("fonts/Sarasa-Mono-SC-Regular.woff2") format("woff2");
    font-display: swap;
}

@font-face {
    /* 除了 PUA，还有修改思源 CN 错误的 U+2E95,U+5F50，必须优先于思源使用 */
    font-family: "example";
    src: url("fonts/example.woff2") format("woff2");
    font-display: swap;
    unicode-range: U+2E95,U+5F50,U+E000-F8FF;
}

@font-face {
    font-family: "IDC";
    src: url("fonts/Ideographic-Description-Character.woff2") format("woff2");
    font-display: swap;
    unicode-range: U+25DC-25DF, U+2FF?, U+31EF, U+1F504;
}

.sm-font,
code,
[class="language-w3cebnf"] * {
    font-family: SM-SC !important;
    font-style: normal;
}

figure {
    display: block;
    margin: 1em auto;
    text-align: center;
    font-weight: 350;
}

figure img {
    display: block;
    max-width: 70%;
    height: auto;
    margin: 0 auto;
    border-radius: 8px;
}

figcaption,
table caption {
    font-size: 0.9em;
    color: var(--color-border);
    line-height: 1.4;
    padding: 0.5em 0;
    text-align: center;
    caption-side: bottom;
}

.ids,
bai-ids {
    white-space: pre-wrap;
    tab-size: 2rem;
}

bai-ids {
    color: var(--color-ids-text);
    background-color: var(--color-surface);
    padding: 2px 4px;
    border-radius: 5px;
    white-space: pre; /* 避免靠近行尾时中间断开 */
    overflow-wrap: anywhere; /* 允许一行放不完时换行 */
}
bai-ids .highlight, .ids .highlight {
    color: var(--color-highlight);
    font-weight: bold;
}

.text-figure {
    /** Figure that use text instead of an image. **/
    width: fit-content;
    margin-inline: auto;
    padding: 16px;
    text-align: center;
    font-size: 2em;
    border: solid 1px var(--color-border);
}
.large-sample {
    font-size: 3em;
    line-height: 1;
}
.fig-arrow {
    font-size: 0.8em;
    line-height: 1;
    margin: 0;
    padding: 0;
}
figure.float-right {
    float: right;
    margin-left: 1em;
    max-width: 50%;
}

p.credits {
    text-indent: 0;
    border-left: var(--color-credit-border) solid 2px;
    padding: 0.5em 2em;
}
div.info {
    text-indent: 0;
    border-left: var(--color-accent) solid 2px;
    padding: 0 2em;
    margin: 0.5em;
}

@media print {
    body {
        padding: 2em;
    }
    code[class="language-w3cebnf"] {
        white-space: pre-wrap !important;
    }
}