/* ============================================================
   Document Number Validator — design tokens (dark mode first)
   ============================================================ */
:root {
    color-scheme: dark;

    --bg: #0b0f14;
    --bg-alt: #10151c;
    --surface: #151b23;
    --surface-2: #1a212b;
    --border: #242d38;
    --text: #e8edf3;
    --muted: #9aa7b4;
    --accent: #4da3ff;
    --accent-strong: #0078d4;
    --accent-strong-hover: #106ebe;
    --ok: #3fb950;
    --ok-bg: rgba(63, 185, 80, 0.12);
    --error: #f85149;
    --error-bg: rgba(248, 81, 73, 0.12);
    --warn: #d29922;
    --warn-bg: rgba(210, 153, 34, 0.12);
    --shadow: 0 8px 30px rgba(0, 0, 0, 0.35);

    --radius: 10px;
    --radius-lg: 16px;
    --container: 1120px;
    --font: "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
    --mono: "Cascadia Code", "Cascadia Mono", Consolas, "Courier New", monospace;
}

[data-theme="light"] {
    color-scheme: light;

    --bg: #ffffff;
    --bg-alt: #f4f6f9;
    --surface: #ffffff;
    --surface-2: #f4f6f9;
    --border: #dde3ea;
    --text: #1b2430;
    --muted: #55606e;
    --accent: #0067b8;
    --accent-strong: #0078d4;
    --accent-strong-hover: #106ebe;
    --ok: #1a7f37;
    --ok-bg: rgba(26, 127, 55, 0.1);
    --error: #cf222e;
    --error-bg: rgba(207, 34, 46, 0.1);
    --warn: #9a6700;
    --warn-bg: rgba(154, 103, 0, 0.1);
    --shadow: 0 8px 30px rgba(16, 24, 40, 0.12);
}

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

html { scroll-behavior: smooth; }

body {
    margin: 0;
    font-family: var(--font);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

code {
    font-family: var(--mono);
    font-size: 0.92em;
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: 5px;
    padding: 0.08em 0.35em;
}

h1, h2, h3 { line-height: 1.2; margin: 0 0 0.5em; font-weight: 650; letter-spacing: -0.01em; }
h1 { font-size: clamp(2.1rem, 5vw, 3.2rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2rem); }
h3 { font-size: 1.12rem; }
p { margin: 0 0 1em; }

.container { max-width: var(--container); margin: 0 auto; padding: 0 1.25rem; }
.narrow { max-width: 760px; }
.center { text-align: center; padding: 4rem 1.25rem; }
.muted { color: var(--muted); }

.skip-link {
    position: absolute;
    left: -9999px;
    top: 0;
    background: var(--accent-strong);
    color: #fff;
    padding: 0.6rem 1rem;
    z-index: 100;
}
.skip-link:focus { left: 0; }

:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
    border-radius: 4px;
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    * { transition: none !important; animation: none !important; }
}

/* ---------- header ---------- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: color-mix(in srgb, var(--bg) 88%, transparent);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
}

.header-inner {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    min-height: 60px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 0.55rem;
    font-weight: 650;
    color: var(--text);
    white-space: nowrap;
}
.brand:hover { text-decoration: none; }
.brand-icon { color: var(--accent); flex-shrink: 0; }

.site-nav { display: flex; gap: 1.1rem; margin-left: auto; flex-wrap: wrap; }
.site-nav a { color: var(--muted); font-size: 0.95rem; }
.site-nav a:hover { color: var(--text); text-decoration: none; }

.theme-toggle {
    margin-left: auto;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
}
.site-nav + .theme-toggle { margin-left: 0; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: none; }

/* ---------- sections ---------- */
.section { padding: 4.25rem 0; }
.section.alt { background: var(--bg-alt); border-block: 1px solid var(--border); }
.section-lead { color: var(--muted); max-width: 62ch; font-size: 1.05rem; margin-bottom: 2rem; }

.eyebrow {
    display: inline-block;
    font-size: 0.82rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 0.9rem;
}

/* ---------- hero ---------- */
.hero { padding: 4.5rem 0 4rem; overflow: hidden; }
.hero-logo { display: block; width: 72px; height: 72px; margin-bottom: 1.1rem; }
.hero-grid {
    display: grid;
    grid-template-columns: 1.05fr 1fr;
    gap: 3rem;
    align-items: center;
}
.hero-lead { font-size: 1.15rem; color: var(--muted); max-width: 54ch; }
.hero-actions { display: flex; gap: 0.75rem; flex-wrap: wrap; margin: 1.5rem 0 1rem; }
.hero-stats { font-size: 0.95rem; }
.hero-stats strong { color: var(--text); }

/* ---------- buttons ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
    padding: 0.62rem 1.2rem;
    border-radius: 8px;
    font-size: 0.97rem;
    font-weight: 600;
    border: 1px solid transparent;
    cursor: pointer;
    transition: background 0.15s ease, border-color 0.15s ease;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--accent-strong); color: #fff; }
.btn-primary:hover { background: var(--accent-strong-hover); }
.btn-secondary { background: var(--surface); color: var(--text); border-color: var(--border); }
.btn-secondary:hover { border-color: var(--accent); }
.btn-ghost { background: transparent; color: var(--text); border-color: var(--border); }
.btn-ghost:hover { border-color: var(--accent); }

/* ---------- cards ---------- */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1.1rem;
}

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.4rem 1.4rem 1.2rem;
    transition: border-color 0.15s ease, transform 0.15s ease;
}
.card:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--border)); }
.card h3 { margin-top: 0.6rem; }
.card p { color: var(--muted); font-size: 0.95rem; margin-bottom: 0; }
.card-icon {
    display: inline-flex;
    width: 44px;
    height: 44px;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    background: color-mix(in srgb, var(--accent) 14%, transparent);
    color: var(--accent);
}

/* ---------- document type cards ---------- */
.group-title {
    margin: 2.2rem 0 0.9rem;
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--muted);
}
.doc-grid { grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }
.doc-card { display: flex; flex-direction: column; gap: 0.55rem; }
.doc-card-head { display: flex; gap: 0.8rem; align-items: center; }
.doc-card-head h3 { margin: 0; }
.doc-card-head a { color: var(--text); }
.doc-card-head a:hover { color: var(--accent); }
.doc-country { margin: 0; font-size: 0.85rem; color: var(--muted); }
.doc-summary { flex-grow: 1; }
.doc-badges { display: flex; gap: 0.45rem; flex-wrap: wrap; margin: 0; }
.doc-card-links { display: flex; gap: 1rem; font-size: 0.92rem; border-top: 1px solid var(--border); padding-top: 0.7rem; }

.badge {
    display: inline-block;
    font-size: 0.78rem;
    font-weight: 600;
    padding: 0.18rem 0.6rem;
    border-radius: 999px;
    border: 1px solid var(--border);
    color: var(--muted);
    background: var(--surface-2);
}
.badge-ok { color: var(--ok); background: var(--ok-bg); border-color: transparent; }
.badge-muted { color: var(--muted); }
.badge-country { color: var(--accent); background: color-mix(in srgb, var(--accent) 12%, transparent); border-color: transparent; }
a.badge:hover { text-decoration: none; border-color: currentColor; }

/* ---------- code ---------- */
.code-window {
    background: #0d1117;
    border: 1px solid #21262d;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
}
.code-window-bar {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.5rem 0.8rem;
    background: #161b22;
    border-bottom: 1px solid #21262d;
}
.dot { width: 10px; height: 10px; border-radius: 50%; background: #30363d; }
.code-window-title { margin-left: 0.5rem; font-size: 0.8rem; color: #8b949e; font-family: var(--mono); }
.code-window-bar .copy-btn { margin-left: auto; }

pre.code {
    margin: 0;
    padding: 1rem 1.1rem;
    overflow-x: auto;
    font-family: var(--mono);
    font-size: 0.88rem;
    line-height: 1.55;
    color: #e6edf3;
    background: #0d1117;
}
pre.code code { background: none; border: none; padding: 0; font-size: inherit; }

.tok-k { color: #ff7b72; }
.tok-s { color: #a5d6ff; }
.tok-c { color: #8b949e; }
.tok-n { color: #79c0ff; }
.tok-t { color: #d2a8ff; }

.copy-btn {
    font-size: 0.78rem;
    font-weight: 600;
    color: #c9d1d9;
    background: #21262d;
    border: 1px solid #30363d;
    border-radius: 6px;
    padding: 0.22rem 0.65rem;
    cursor: pointer;
}
.copy-btn:hover { background: #30363d; }
.copy-btn.copied { color: var(--ok); border-color: var(--ok); }

/* ---------- tabs ---------- */
.tabs { border: 1px solid var(--border); border-radius: var(--radius-lg); overflow: hidden; background: var(--surface); }
.tablist {
    display: flex;
    gap: 0.25rem;
    padding: 0.5rem 0.6rem 0;
    background: var(--surface-2);
    border-bottom: 1px solid var(--border);
    overflow-x: auto;
}
.tablist [role="tab"] {
    font: inherit;
    font-size: 0.93rem;
    font-weight: 600;
    color: var(--muted);
    background: none;
    border: none;
    border-bottom: 2px solid transparent;
    padding: 0.55rem 1rem;
    cursor: pointer;
    white-space: nowrap;
}
.tablist [role="tab"]:hover { color: var(--text); }
.tablist [role="tab"][aria-selected="true"] { color: var(--accent); border-bottom-color: var(--accent); }
.tabpanel { position: relative; background: #0d1117; }
.tabpanel .copy-btn { position: absolute; top: 0.6rem; right: 0.7rem; z-index: 2; }
.tabpanel pre.code { padding-top: 1.4rem; }

/* ---------- demo ---------- */
.demo-form {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    align-items: flex-end;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.4rem;
}
.field { display: flex; flex-direction: column; gap: 0.4rem; min-width: 200px; }
.field-grow { flex: 1 1 260px; }
.field label, .field-label { font-size: 0.88rem; font-weight: 600; color: var(--muted); }
.field input, .field select {
    font: inherit;
    color: var(--text);
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.6rem 0.75rem;
    width: 100%;
}
.field input:focus, .field select:focus { border-color: var(--accent); outline: none; }
.field small { font-size: 0.8rem; }
.demo-actions { flex-direction: row; gap: 0.6rem; align-items: center; }
.demo-actions .btn { justify-content: center; }
.demo-selected-note { color: var(--muted); font-size: 0.95rem; }
.doc-chip {
    display: inline-flex;
    gap: 0.5rem;
    align-items: baseline;
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 0.4rem 0.9rem;
    font-weight: 600;
    width: fit-content;
}

.alert {
    margin-top: 1rem;
    padding: 0.75rem 1rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.95rem;
    border: 1px solid transparent;
}
.alert-success { color: var(--ok); background: var(--ok-bg); border-color: color-mix(in srgb, var(--ok) 40%, transparent); }
.alert-error { color: var(--error); background: var(--error-bg); border-color: color-mix(in srgb, var(--error) 40%, transparent); }
.alert-warn { color: var(--warn); background: var(--warn-bg); border-color: color-mix(in srgb, var(--warn) 40%, transparent); }
.alert-info { color: var(--accent); background: color-mix(in srgb, var(--accent) 12%, transparent); }

/* ---------- get started ---------- */
.getstarted-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 2rem; }
.link-cards { display: flex; gap: 0.8rem; flex-wrap: wrap; margin-top: 1.2rem; }
.link-card {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 1rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text);
    font-weight: 600;
    font-size: 0.93rem;
}
.link-card:hover { border-color: var(--accent); text-decoration: none; }
.link-card .icon { color: var(--accent); }

/* ---------- contributing ---------- */
.contributing { text-align: center; }
.contributing .section-lead { margin-left: auto; margin-right: auto; }
.contributing-badges { display: flex; gap: 0.5rem; justify-content: center; margin-bottom: 1.4rem; }

/* ---------- landing ---------- */
.landing-hero {
    padding: 3rem 0 2.5rem;
    background: var(--bg-alt);
    border-bottom: 1px solid var(--border);
}
.breadcrumb { display: flex; gap: 0.5rem; font-size: 0.88rem; color: var(--muted); margin-bottom: 1.2rem; }
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--text); }
.landing-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 2.5rem; }
.example-value { font-size: 1rem; }
.example-value code { font-size: 1.02rem; color: var(--ok); }
.faq { display: flex; flex-direction: column; gap: 0.7rem; margin-bottom: 2rem; }
.faq details {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 0.85rem 1.1rem;
}
.faq summary { font-weight: 600; cursor: pointer; }
.faq details p { margin: 0.6rem 0 0; color: var(--muted); }
.related-links { display: flex; gap: 0.5rem; flex-wrap: wrap; }

/* ---------- footer ---------- */
.site-footer {
    border-top: 1px solid var(--border);
    background: var(--bg-alt);
    padding: 2.5rem 0;
    margin-top: 2rem;
}
.footer-inner { display: flex; flex-direction: column; gap: 1rem; }
.footer-brand { display: flex; align-items: baseline; gap: 0.8rem; flex-wrap: wrap; }
.footer-nav { display: flex; gap: 1.2rem; flex-wrap: wrap; }
.footer-nav a { color: var(--muted); font-size: 0.93rem; }
.footer-nav a:hover { color: var(--text); }
.footer-copy { margin: 0; font-size: 0.88rem; }
.version-badge {
    font-family: var(--mono);
    font-size: 0.78rem;
    color: var(--accent);
    background: color-mix(in srgb, var(--accent) 12%, transparent);
    border-radius: 999px;
    padding: 0.12rem 0.6rem;
}

/* ---------- responsive ---------- */
@media (max-width: 900px) {
    .hero-grid, .getstarted-grid, .landing-grid { grid-template-columns: 1fr; }
    .header-inner { flex-wrap: wrap; padding-top: 0.55rem; padding-bottom: 0.55rem; }
    .site-nav { order: 3; width: 100%; margin-left: 0; gap: 0.9rem; }
    .theme-toggle { margin-left: auto; }
    .section { padding: 3rem 0; }
    .demo-form { flex-direction: column; align-items: stretch; }
    .demo-actions { justify-content: stretch; }
    .demo-actions .btn { flex: 1; }
}