/* RMath Documentation Portal — Design System */
:root {
    --bg-main: #0b0f19;
    --bg-surface: #111827;
    --bg-card: rgba(17, 24, 39, 0.8);
    --bg-sidebar: rgba(11, 15, 25, 0.95);
    --bg-code: #0d1117;

    --accent: #818cf8;
    --accent-hover: #a5b4fc;
    --accent-dim: rgba(129, 140, 248, 0.12);
    --accent-border: rgba(129, 140, 248, 0.25);
    --cyan: #22d3ee;

    --text: #e2e8f0;
    --text-dim: #94a3b8;
    --text-heading: #f8fafc;

    --border: rgba(51, 65, 85, 0.6);
    --radius: 10px;
    --radius-lg: 16px;

    --font: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --mono: 'Fira Code', 'Cascadia Code', 'JetBrains Mono', Consolas, monospace;

    --sidebar-w: 260px;
    --ease: cubic-bezier(0.4, 0, 0.2, 1);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
    background: var(--bg-main);
    color: var(--text);
    font-family: var(--font);
    font-size: 15px;
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; transition: color 0.15s; }
a:hover { color: var(--accent-hover); }

/* ─── LAYOUT ────────────────────────────────────────────────── */

.portal { display: flex; min-height: 100vh; }

/* ─── SIDEBAR ───────────────────────────────────────────────── */

.sidebar {
    width: var(--sidebar-w);
    background: var(--bg-sidebar);
    border-right: 1px solid var(--border);
    height: 100vh;
    position: fixed;
    left: 0; top: 0;
    z-index: 100;
    padding: 1.5rem 1rem;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    scrollbar-width: thin;
    scrollbar-color: var(--accent) transparent;
}

.sidebar::-webkit-scrollbar { width: 3px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--accent); border-radius: 10px; }

.sidebar-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 0 0.5rem;
    margin-bottom: 1.5rem;
    text-decoration: none;
}

.sidebar-brand img { width: 32px; height: 32px; border-radius: 8px; }

.sidebar-brand span {
    font-weight: 700;
    font-size: 1.05rem;
    color: var(--text-heading);
    letter-spacing: -0.3px;
}

.sidebar-brand small {
    font-size: 0.7rem;
    color: var(--text-dim);
    margin-left: 4px;
    font-weight: 400;
}

/* Search */
.sidebar-search {
    position: relative;
    margin-bottom: 1.5rem;
    padding: 0 0.25rem;
}

.sidebar-search input {
    width: 100%;
    background: rgba(255,255,255,0.04);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.55rem 0.75rem 0.55rem 2.2rem;
    color: var(--text);
    font-family: var(--font);
    font-size: 0.85rem;
    outline: none;
    transition: border-color 0.2s, background 0.2s;
}

.sidebar-search input:focus {
    border-color: var(--accent);
    background: rgba(255,255,255,0.06);
}

.sidebar-search .icon {
    position: absolute;
    left: 14px; top: 50%;
    transform: translateY(-50%);
    opacity: 0.4;
    font-size: 0.8rem;
    pointer-events: none;
}

/* Nav groups */
.nav-group { margin-bottom: 1.2rem; }

.nav-group-title {
    text-transform: uppercase;
    font-size: 0.68rem;
    font-weight: 600;
    color: var(--text-dim);
    letter-spacing: 0.8px;
    padding: 0 0.75rem;
    margin-bottom: 0.4rem;
}

.nav-link {
    display: block;
    padding: 0.4rem 0.75rem;
    color: var(--text-dim);
    border-radius: 6px;
    font-size: 0.87rem;
    transition: all 0.15s var(--ease);
    position: relative;
}

.nav-link:hover { color: var(--text); background: rgba(255,255,255,0.04); }

.nav-link.active {
    color: var(--accent);
    background: var(--accent-dim);
    font-weight: 500;
}

.nav-link.active::before {
    content: '';
    position: absolute;
    left: 0; top: 25%; height: 50%;
    width: 3px;
    background: var(--accent);
    border-radius: 0 3px 3px 0;
}

.nav-link code {
    font-family: var(--mono);
    font-size: 0.82rem;
}

/* ─── MAIN CONTENT ──────────────────────────────────────────── */

.content {
    flex: 1;
    margin-left: var(--sidebar-w);
    padding: 3rem 4rem 6rem;
    max-width: 960px;
}

/* ─── HERO ──────────────────────────────────────────────────── */

.hero { margin-bottom: 4rem; animation: fadeUp 0.5s var(--ease); }

@keyframes fadeUp {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}

.badge {
    display: inline-block;
    padding: 3px 10px;
    background: var(--accent-dim);
    border: 1px solid var(--accent-border);
    border-radius: 20px;
    color: var(--accent);
    font-size: 0.78rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

h1 {
    font-size: 2.8rem;
    font-weight: 800;
    letter-spacing: -1.5px;
    line-height: 1.15;
    margin-bottom: 1rem;
    color: var(--text-heading);
}

.gradient-text {
    background: linear-gradient(135deg, var(--accent), var(--cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-sub {
    font-size: 1.1rem;
    color: var(--text-dim);
    max-width: 620px;
    margin-bottom: 2rem;
    line-height: 1.7;
}

.hero-actions { display: flex; gap: 12px; margin-bottom: 2.5rem; flex-wrap: wrap; }

.btn {
    display: inline-flex;
    align-items: center;
    padding: 0.6rem 1.4rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.9rem;
    border: none;
    cursor: pointer;
    transition: all 0.2s var(--ease);
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, #6366f1, #818cf8);
    color: white;
}

.btn-primary:hover { color: white; transform: translateY(-1px); box-shadow: 0 4px 16px rgba(99,102,241,0.35); }

.btn-outline {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text);
}

.btn-outline:hover { border-color: var(--accent); color: var(--accent); }

/* ─── CODE WINDOW ───────────────────────────────────────────── */

.code-window {
    background: var(--bg-code);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    margin: 1.5rem 0;
}

.code-header {
    background: rgba(255,255,255,0.02);
    padding: 0.6rem 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--border);
}

.dots { display: flex; gap: 6px; }
.dots span { width: 10px; height: 10px; border-radius: 50%; }
.dots .r { background: #ef4444; }
.dots .y { background: #eab308; }
.dots .g { background: #22c55e; }

.code-header .filename { font-size: 0.75rem; color: var(--text-dim); font-family: var(--mono); }

.copy-btn {
    background: rgba(255,255,255,0.06);
    border: 1px solid var(--border);
    color: var(--text-dim);
    padding: 3px 10px;
    border-radius: 5px;
    font-size: 0.72rem;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.15s;
}

.copy-btn:hover { background: var(--accent); color: white; border-color: var(--accent); }

pre {
    padding: 1.25rem;
    font-family: var(--mono);
    font-size: 0.85rem;
    overflow-x: auto;
    color: #c9d1d9;
    line-height: 1.6;
}

.kw { color: #ff7b72; }
.fn { color: #d2a8ff; }
.str { color: #a5d6ff; }
.cm { color: #8b949e; }
.num { color: #79c0ff; }

/* ─── SECTION HEADINGS ──────────────────────────────────────── */

h2 {
    font-size: 1.8rem;
    font-weight: 700;
    margin: 3rem 0 1rem;
    color: var(--text-heading);
    letter-spacing: -0.5px;
}

h3 {
    font-size: 1.2rem;
    font-weight: 600;
    margin: 2rem 0 0.75rem;
    color: var(--text-heading);
}

/* ─── MODULE CARDS ──────────────────────────────────────────── */

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 16px;
    margin: 1.5rem 0;
}

.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    transition: all 0.25s var(--ease);
    text-decoration: none;
    display: block;
}

.card:hover {
    transform: translateY(-4px);
    border-color: var(--accent-border);
    box-shadow: 0 8px 24px rgba(0,0,0,0.3), 0 0 0 1px var(--accent-border);
}

.card h3 { margin: 0 0 0.5rem; font-size: 1.05rem; color: var(--text-heading); }
.card p { color: var(--text-dim); font-size: 0.88rem; margin: 0; line-height: 1.55; }

.card .card-icon {
    display: inline-block;
    width: 32px; height: 32px;
    border-radius: 8px;
    background: var(--accent-dim);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 0.75rem;
    font-size: 1rem;
}

/* ─── API TABLE ─────────────────────────────────────────────── */

.api-table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0 2rem;
    font-size: 0.88rem;
}

.api-table th {
    text-align: left;
    padding: 0.75rem 1rem;
    color: var(--accent);
    font-weight: 600;
    border-bottom: 2px solid var(--border);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.api-table td {
    padding: 0.65rem 1rem;
    border-bottom: 1px solid var(--border);
    vertical-align: top;
}

.api-table tr:last-child td { border-bottom: none; }

.api-table tr:hover td { background: rgba(255,255,255,0.02); }

.api-table code, .method-sig {
    font-family: var(--mono);
    font-size: 0.82rem;
    color: var(--cyan);
}

.api-table .desc { color: var(--text-dim); }
.api-table .returns { color: var(--text-dim); font-family: var(--mono); font-size: 0.8rem; }

.api-section {
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    background: var(--bg-card);
    margin: 1.5rem 0;
}

.api-section-title {
    padding: 0.75rem 1rem;
    background: rgba(255,255,255,0.02);
    border-bottom: 1px solid var(--border);
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-heading);
}

/* ─── INFO CALLOUT ──────────────────────────────────────────── */

.callout {
    padding: 1rem 1.25rem;
    border-radius: var(--radius);
    border-left: 3px solid var(--accent);
    background: var(--accent-dim);
    margin: 1.5rem 0;
    font-size: 0.9rem;
    color: var(--text);
}

.callout strong { color: var(--accent); }

.install-cmd {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--bg-code);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 0.8rem 1.2rem;
    font-family: var(--mono);
    font-size: 0.9rem;
    margin: 1rem 0;
    color: var(--cyan);
}

.install-cmd .dollar { color: var(--text-dim); user-select: none; }

/* ─── FOOTER ────────────────────────────────────────────────── */

.footer {
    margin-top: 5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border);
    color: var(--text-dim);
    font-size: 0.82rem;
}

/* ─── MOBILE ────────────────────────────────────────────────── */

.menu-toggle {
    display: none;
    position: fixed;
    top: 16px; right: 16px;
    z-index: 200;
    background: linear-gradient(135deg, #6366f1, #818cf8);
    border: none;
    border-radius: 10px;
    padding: 10px;
    cursor: pointer;
    box-shadow: 0 2px 12px rgba(99,102,241,0.4);
}

.menu-toggle span {
    display: block;
    width: 20px; height: 2px;
    background: white;
    margin: 4px 0;
    transition: 0.3s;
}

.overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.6);
    backdrop-filter: blur(4px);
    z-index: 95;
}

.overlay.active { display: block; }

@media (max-width: 860px) {
    .menu-toggle { display: block; }

    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.35s var(--ease);
        width: 280px;
        box-shadow: 8px 0 30px rgba(0,0,0,0.4);
    }

    .sidebar.open { transform: translateX(0); }

    .content {
        margin-left: 0;
        padding: 2.5rem 1.5rem 4rem;
    }

    h1 { font-size: 2rem; }
    .hero-sub { font-size: 1rem; }
    .card-grid { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
    .content { padding: 2rem 1rem 3rem; }
    h1 { font-size: 1.6rem; }
    h2 { font-size: 1.4rem; }
    .hero-actions { flex-direction: column; }
    .btn { width: 100%; justify-content: center; }
}