:root {
    --bg: #f5fafb;
    --surface: #ffffff;
    --text: #161d1d;
    --text-muted: #3f484a;
    --border: #dae4e5;
    --brand: #02c1d0;
    --link: #006972;
    --draft-bg: #fff4d6;
    --draft-border: #e0b44c;
    --draft-text: #5c4200;
    --todo-bg: #ffe08a;
    --todo-text: #3d2c00;
    color-scheme: light;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0f1117;
        --surface: #1a1d27;
        --text: #dee4e4;
        --text-muted: #bec8c9;
        --border: #2b3132;
        --link: #4fd8e4;
        --draft-bg: #3a2f12;
        --draft-border: #8a6d1f;
        --draft-text: #ffe6a6;
        --todo-bg: #6b5212;
        --todo-text: #fff1c7;
        color-scheme: dark;
    }
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    -webkit-text-size-adjust: 100%;
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family:
        system-ui,
        -apple-system,
        'Segoe UI',
        Roboto,
        'Helvetica Neue',
        Arial,
        sans-serif;
    font-size: 1rem;
    line-height: 1.65;
}

a {
    color: var(--link);
    text-underline-offset: 2px;
}

.site-header {
    border-top: 4px solid var(--brand);
    border-bottom: 1px solid var(--border);
    background: var(--surface);
}

.site-header .wrap {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 8px 24px;
    padding-top: 14px;
    padding-bottom: 14px;
}

.brand {
    color: var(--text);
    font-weight: 700;
    font-size: 1.125rem;
    letter-spacing: 0.02em;
    text-decoration: none;
}

.site-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 4px 20px;
    font-size: 0.9375rem;
}

.site-nav a {
    text-decoration: none;
}

.site-nav a[aria-current='page'] {
    color: var(--text);
    font-weight: 600;
}

.wrap {
    max-width: 760px;
    margin: 0 auto;
    padding-left: 16px;
    padding-right: 16px;
}

main.wrap {
    padding-top: 32px;
    padding-bottom: 48px;
}

h1 {
    margin: 0 0 4px;
    font-size: 1.875rem;
    line-height: 1.25;
}

h2 {
    margin: 40px 0 12px;
    padding-top: 8px;
    font-size: 1.375rem;
    line-height: 1.3;
    scroll-margin-top: 16px;
}

h3 {
    margin: 28px 0 8px;
    font-size: 1.125rem;
    line-height: 1.35;
    scroll-margin-top: 16px;
}

p,
ul {
    margin: 0 0 14px;
}

ul {
    padding-left: 1.4em;
}

li + li {
    margin-top: 6px;
}

.updated {
    margin-bottom: 24px;
    color: var(--text-muted);
    font-size: 0.9375rem;
}

.draft {
    margin: 0 0 24px;
    padding: 12px 16px;
    border: 1px solid var(--draft-border);
    border-radius: 8px;
    background: var(--draft-bg);
    color: var(--draft-text);
    font-size: 0.9375rem;
}

mark.todo {
    padding: 0 3px;
    border-radius: 3px;
    background: var(--todo-bg);
    color: var(--todo-text);
}

.toc {
    margin: 0 0 8px;
    padding: 16px 20px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--surface);
}

.toc h2 {
    margin: 0 0 8px;
    padding: 0;
    font-size: 1rem;
}

.toc ol {
    margin: 0;
    padding-left: 1.4em;
}

.toc li + li {
    margin-top: 2px;
}

.doc-list {
    padding: 0;
    list-style: none;
}

.doc-list li + li {
    margin-top: 12px;
}

.doc-list a {
    display: block;
    padding: 16px 20px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--surface);
    font-weight: 600;
    text-decoration: none;
}

.site-footer {
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.875rem;
}

.site-footer .wrap {
    padding-top: 20px;
    padding-bottom: 32px;
}

.site-footer p {
    margin: 0 0 6px;
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.5rem;
    }

    h2 {
        font-size: 1.25rem;
    }

    main.wrap {
        padding-top: 24px;
    }
}

@media print {
    body {
        background: #ffffff;
        color: #000000;
    }

    .site-header,
    .site-footer,
    .toc {
        display: none;
    }

    a {
        color: inherit;
    }

    h2,
    h3 {
        break-after: avoid;
    }
}