:root {

    --bg-primary: #0a0a0a;
    --bg-secondary: #141414;
    --bg-tertiary: #1f1f1f;
    --text-primary: #ffffff;
    --text-secondary: #a0a0a0;
    --text-muted: #666666;
    --border-color: #2a2a2a;
    --accent: #ffffff;
    --link-color: #82b1ff;
    --success: #2ecc71;
    --warning: #f39c12;
    --transition: 0.3s ease;
}

[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f5;
    --bg-tertiary: #ebebeb;
    --text-primary: #0a0a0a;
    --text-secondary: #555555;
    --text-muted: #888888;
    --border-color: #e0e0e0;
    --accent: #0a0a0a;
    --link-color: #1a73e8;
    --success: #27ae60;
    --warning: #e67e22;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color var(--transition), color var(--transition);
    line-height: 1.6;
}

header {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.back-link {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color var(--transition);
}

.back-link:hover {
    color: var(--text-primary);
}

h1 {
    font-weight: 600;
    font-size: 1.25rem;
    letter-spacing: -0.02em;
}

.theme-toggle {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.theme-toggle-btn {
    width: 48px;
    height: 26px;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 13px;
    cursor: pointer;
    position: relative;
    transition: all var(--transition);
}

.theme-toggle-btn::after {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    background: var(--text-primary);
    border-radius: 50%;
    top: 2px;
    left: 2px;
    transition: transform var(--transition);
}

[data-theme="light"] .theme-toggle-btn::after {
    transform: translateX(22px);
}

.theme-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
}

main {
    flex: 1;
    display: flex;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

.sidebar {
    width: 260px;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    padding: 2rem 0;
    position: sticky;
    top: 60px;
    height: calc(100vh - 60px);
    overflow-y: auto;
}

.nav-section {
    margin-bottom: 1.5rem;
    padding: 0 1.5rem;
}

.nav-section h3 {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
    font-weight: 600;
}

.nav-section a {
    display: block;
    color: var(--text-secondary);
    text-decoration: none;
    padding: 0.4rem 0;
    font-size: 0.875rem;
    transition: color var(--transition);
}

.nav-section a:hover {
    color: var(--text-primary);
}

.content {
    flex: 1;
    padding: 3rem 4rem;
    max-width: 900px;
}

section {
    margin-bottom: 4rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
}

section:last-of-type {
    border-bottom: none;
}

h2 {
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

h3 {
    font-size: 1.1rem;
    font-weight: 500;
    margin: 1.5rem 0 0.75rem;
    color: var(--text-primary);
}

h4 {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

ol,
ul {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

li {
    margin-bottom: 0.5rem;
}

strong {
    color: var(--text-primary);
}

.complexity-badge {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.complexity-badge span {
    background: var(--bg-tertiary);
    padding: 0.35rem 0.75rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-family: 'SF Mono', 'Consolas', monospace;
    color: var(--text-secondary);
}

.complexity-badge .time {
    border-left: 3px solid var(--success);
}

.complexity-badge .space {
    border-left: 3px solid var(--link-color);
}

.info-box {
    background: var(--bg-tertiary);
    border-left: 3px solid var(--link-color);
    padding: 1rem 1.25rem;
    border-radius: 0 6px 6px 0;
    margin: 1rem 0;
}

.info-box.warning {
    border-left-color: var(--warning);
}

.info-box h4 {
    margin-bottom: 0.75rem;
}

.info-box ol {
    margin-bottom: 0;
}

.pros-cons {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin: 1.5rem 0;
}

.pros,
.cons {
    background: var(--bg-tertiary);
    padding: 1.25rem;
    border-radius: 8px;
}

.pros h4 {
    color: var(--success);
}

.cons h4 {
    color: #e74c3c;
}

.pros ul,
.cons ul {
    list-style: none;
    margin-left: 0;
    margin-bottom: 0;
}

.pros li,
.cons li {
    padding-left: 1.25rem;
    position: relative;
}

.pros li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success);
}

.cons li::before {
    content: '✗';
    position: absolute;
    left: 0;
    color: #e74c3c;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin: 1.5rem 0;
}

.feature-card {
    background: var(--bg-tertiary);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.feature-card h4 {
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.feature-card ul {
    margin-bottom: 0;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0;
}

.data-table th,
.data-table td {
    padding: 0.75rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.data-table th {
    background: var(--bg-tertiary);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    font-weight: 600;
}

.data-table td {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.data-table tr:hover td {
    background: var(--bg-tertiary);
}

footer {
    margin-top: 4rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--text-muted);
    font-size: 0.875rem;
}

@media (max-width: 900px) {
    .sidebar {
        display: none;
    }

    .content {
        padding: 2rem;
    }

    .pros-cons {
        grid-template-columns: 1fr;
    }
}

::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* ─── Doc Version Switcher ─── */
.doc-version-switcher {
    display: flex;
    gap: 0.25rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.2rem;
}

.doc-version-switcher .version-link {
    padding: 0.35rem 0.85rem;
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 500;
    text-decoration: none;
    color: var(--text-muted);
    transition: all 0.2s ease;
    white-space: nowrap;
}

.doc-version-switcher .version-link:hover {
    color: var(--text-primary);
    background: var(--bg-secondary);
}

.doc-version-switcher .version-link.active {
    background: var(--text-primary);
    color: var(--bg-primary);
    font-weight: 600;
}

/* ─── Code Blocks ─── */
code {
    font-family: 'SF Mono', 'Consolas', 'Courier New', monospace;
    background: var(--bg-tertiary);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-size: 0.85em;
    color: var(--link-color);
}

pre {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.25rem 1.5rem;
    overflow-x: auto;
    margin: 1rem 0;
    line-height: 1.5;
}

pre code {
    background: none;
    padding: 0;
    border-radius: 0;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* ─── Active Nav Link ─── */
.nav-section a.active {
    color: var(--text-primary);
    font-weight: 600;
}

/* ─── API Reference List ─── */
.api-list {
    list-style: none;
    margin-left: 0;
}

.api-list li {
    padding: 0.35rem 0;
    border-bottom: 1px solid var(--border-color);
}

.api-list li:last-child {
    border-bottom: none;
}

/* ─── Responsive Header ─── */
@media (max-width: 900px) {
    .header-content {
        flex-wrap: wrap;
        gap: 0.5rem;
    }

    .header-content h1 {
        order: -1;
        width: 100%;
        text-align: center;
    }

    .doc-version-switcher {
        order: 1;
        margin: 0 auto;
    }
}

@media (max-width: 600px) {
    .doc-version-switcher .version-link {
        padding: 0.3rem 0.6rem;
        font-size: 0.72rem;
    }
}