/* ==========================================================================
   OpenMythos 学习教程 — Design System
   ==========================================================================
   Table of Contents
   1.  CSS Reset / Normalize
   2.  Color Variables (Dark & Light Themes)
   3.  Typography
   4.  Layout (Sidebar, Content, Responsive)
   5.  Top Bar & Progress Bar
   6.  Sidebar Navigation
   7.  Content Typography (headings, paragraphs, lists, tables, blockquotes)
   8.  Code Block Styles (copy button, source label)
   9.  Card / Grid Components
   10. Button Styles
   11. Mobile Hamburger Menu
   12. Scrollbar Styling
   13. Transitions & Animations
   14. SVG Container Styles
   15. Table Styles
   16. Callout / Admonition Styles
   17. Utilities & Loading
   ========================================================================== */

/* ==========================================================================
   1. CSS Reset / Normalize
   ========================================================================== */

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

html {
    -webkit-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    min-height: 100vh;
    line-height: 1.7;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    font-size: 16px;
    color: var(--om-text);
    background: var(--om-bg);
    transition: background-color 0.3s ease, color 0.3s ease;
    overflow-x: hidden;
}

img,
svg {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--om-accent);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--om-accent-hover);
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
    color: inherit;
}

ul,
ol {
    list-style: none;
}

input,
button {
    font-size: inherit;
}

/* ==========================================================================
   2. Color Variables (Dark & Light Themes)
   ========================================================================== */

:root {
    /* Accent — modern blue-purple */
    --om-accent: #7c3aed;
    --om-accent-hover: #6d28d9;
    --om-accent-light: #8b5cf6;
    --om-accent-soft: rgba(124, 58, 237, 0.12);
    --om-accent-gradient: linear-gradient(135deg, #7c3aed 0%, #6366f1 100%);

    /* Shared */
    --om-code-bg: #1e1e2e;
    --om-code-text: #cdd6f4;
    --om-code-border: #313244;

    /* Transition */
    --om-transition: 0.3s ease;

    /* Layout dims */
    --om-sidebar-width: 280px;
    --om-topbar-height: 64px;
    --om-content-max: 800px;
    --om-radius: 8px;
    --om-radius-lg: 12px;
    --om-radius-sm: 6px;
}

/* Dark theme (default) */
[data-theme="dark"] {
    --om-bg: #0d1117;
    --om-bg-alt: #161b22;
    --om-bg-elevated: #1c2128;
    --om-bg-hover: #21262d;
    --om-surface: #161b22;
    --om-surface-2: #1c2128;
    --om-border: #30363d;
    --om-border-light: #21262d;
    --om-text: #e6edf3;
    --om-text-secondary: #9da7b3;
    --om-text-muted: #6e7681;
    --om-heading: #f0f6fc;

    --om-accent: #7c3aed;
    --om-accent-hover: #8b5cf6;
    --om-accent-soft: rgba(124, 58, 237, 0.18);

    --om-success: #3fb950;
    --om-warning: #d29922;
    --om-danger: #f85149;
    --om-info: #58a6ff;

    --om-shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
    --om-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
    --om-shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.6);

    --om-code-bg: #1e1e2e;
    --om-code-text: #cdd6f4;
    --om-code-inline-bg: rgba(110, 118, 129, 0.2);

    --om-topbar-bg: rgba(13, 17, 23, 0.85);
    --om-sidebar-bg: #0d1117;
    --om-progress-bg: rgba(124, 58, 237, 0.2);
}

/* Light theme */
[data-theme="light"] {
    --om-bg: #ffffff;
    --om-bg-alt: #f8fafc;
    --om-bg-elevated: #ffffff;
    --om-bg-hover: #f1f5f9;
    --om-surface: #ffffff;
    --om-surface-2: #f8fafc;
    --om-border: #e2e8f0;
    --om-border-light: #edf2f7;
    --om-text: #1e293b;
    --om-text-secondary: #475569;
    --om-text-muted: #94a3b8;
    --om-heading: #0f172a;

    --om-accent: #7c3aed;
    --om-accent-hover: #6d28d9;
    --om-accent-soft: rgba(124, 58, 237, 0.08);

    --om-success: #16a34a;
    --om-warning: #ca8a04;
    --om-danger: #dc2626;
    --om-info: #2563eb;

    --om-shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.06);
    --om-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    --om-shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);

    --om-code-bg: #1e1e2e;
    --om-code-text: #cdd6f4;
    --om-code-inline-bg: rgba(124, 58, 237, 0.08);

    --om-topbar-bg: rgba(255, 255, 255, 0.85);
    --om-sidebar-bg: #f8fafc;
    --om-progress-bg: rgba(124, 58, 237, 0.15);
}

/* ==========================================================================
   3. Typography
   ========================================================================== */

h1, h2, h3, h4, h5, h6 {
    color: var(--om-heading);
    font-weight: 700;
    line-height: 1.3;
    letter-spacing: -0.01em;
}

h1 { font-size: 2.25rem; margin: 0 0 1rem; }
h2 { font-size: 1.75rem; margin: 2.5rem 0 1rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--om-border-light); }
h3 { font-size: 1.35rem; margin: 2rem 0 0.75rem; }
h4 { font-size: 1.1rem; margin: 1.5rem 0 0.5rem; }
h5 { font-size: 1rem; margin: 1.25rem 0 0.5rem; }
h6 { font-size: 0.9rem; margin: 1rem 0 0.5rem; color: var(--om-text-secondary); }

p { margin: 0 0 1rem; }

code, pre, kbd {
    font-family: "JetBrains Mono", "Fira Code", "SF Mono", Consolas, "Liberation Mono", monospace;
}

/* ==========================================================================
   4. Layout
   ========================================================================== */

.om-layout {
    display: flex;
    align-items: flex-start;
    max-width: 100%;
    min-height: calc(100vh - var(--om-topbar-height));
}

.om-main {
    flex: 1;
    min-width: 0;
    padding-top: var(--om-topbar-height);
    margin-left: var(--om-sidebar-width);
    transition: margin-left var(--om-transition);
}

.om-content-wrap {
    display: flex;
    justify-content: center;
    padding: 2.5rem 2rem 6rem;
}

.om-content {
    width: 100%;
    max-width: var(--om-content-max);
}

/* ==========================================================================
   5. Top Bar & Progress Bar
   ========================================================================== */

.om-progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    width: 0%;
    background: var(--om-accent-gradient);
    z-index: 1001;
    transition: width 0.1s linear;
    box-shadow: 0 0 10px rgba(124, 58, 237, 0.5);
}

.om-topbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--om-topbar-height);
    background: var(--om-topbar-bg);
    backdrop-filter: saturate(180%) blur(12px);
    -webkit-backdrop-filter: saturate(180%) blur(12px);
    border-bottom: 1px solid var(--om-border);
    z-index: 1000;
    transition: background-color var(--om-transition), border-color var(--om-transition);
}

.om-topbar-inner {
    height: 100%;
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0 1.5rem;
    max-width: 100%;
}

.om-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--om-heading);
    font-weight: 700;
    font-size: 1.05rem;
    margin-right: auto;
}

.om-brand:hover {
    color: var(--om-accent);
}

.om-brand-icon {
    font-size: 1.4rem;
    line-height: 1;
}

.om-brand-text {
    background: var(--om-accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.om-brand-sub {
    color: var(--om-text-muted);
    font-size: 0.8rem;
    font-weight: 500;
    padding-left: 0.5rem;
    margin-left: 0.25rem;
    border-left: 1px solid var(--om-border);
}

.om-topbar-actions {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.om-search-trigger {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.4rem 0.75rem;
    border-radius: var(--om-radius-sm);
    background: var(--om-bg-alt);
    border: 1px solid var(--om-border);
    color: var(--om-text-muted);
    font-size: 0.85rem;
    transition: all var(--om-transition);
}

.om-search-trigger:hover {
    border-color: var(--om-accent);
    color: var(--om-text);
    background: var(--om-bg-hover);
}

.om-search-hint {
    display: inline;
}

.om-kbd {
    display: inline-flex;
    align-items: center;
    padding: 0.1rem 0.4rem;
    font-size: 0.7rem;
    font-family: "JetBrains Mono", monospace;
    background: var(--om-bg-elevated);
    border: 1px solid var(--om-border);
    border-radius: 4px;
    color: var(--om-text-secondary);
    line-height: 1.4;
}

.om-theme-toggle,
.om-github-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 38px;
    height: 38px;
    border-radius: var(--om-radius-sm);
    color: var(--om-text-secondary);
    transition: all var(--om-transition);
}

.om-theme-toggle:hover,
.om-github-link:hover {
    background: var(--om-bg-hover);
    color: var(--om-accent);
}

.om-theme-toggle .om-icon-sun,
.om-theme-toggle .om-icon-moon {
    position: absolute;
    transition: opacity var(--om-transition), transform var(--om-transition);
}

.om-theme-toggle {
    position: relative;
    overflow: hidden;
}

[data-theme="dark"] .om-icon-sun { opacity: 1; transform: rotate(0deg); }
[data-theme="dark"] .om-icon-moon { opacity: 0; transform: rotate(-90deg); }
[data-theme="light"] .om-icon-sun { opacity: 0; transform: rotate(90deg); }
[data-theme="light"] .om-icon-moon { opacity: 1; transform: rotate(0deg); }

/* ==========================================================================
   6. Sidebar Navigation
   ========================================================================== */

.om-sidebar {
    position: fixed;
    top: var(--om-topbar-height);
    left: 0;
    bottom: 0;
    width: var(--om-sidebar-width);
    background: var(--om-sidebar-bg);
    border-right: 1px solid var(--om-border);
    overflow-y: auto;
    overflow-x: hidden;
    z-index: 999;
    transition: transform var(--om-transition), background-color var(--om-transition);
}

.om-nav {
    padding: 1.25rem 0.75rem 2rem;
}

.om-nav-list {
    display: flex;
    flex-direction: column;
    gap: 0.15rem;
}

.om-nav-item {
    margin-bottom: 0.15rem;
}

.om-nav-link {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.5rem 0.75rem;
    border-radius: var(--om-radius-sm);
    color: var(--om-text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.2s ease;
    line-height: 1.4;
}

.om-nav-link:hover {
    background: var(--om-bg-hover);
    color: var(--om-text);
}

.om-nav-link.active {
    background: var(--om-accent-soft);
    color: var(--om-accent);
    font-weight: 600;
}

.om-nav-link.active::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 60%;
    background: var(--om-accent);
    border-radius: 0 3px 3px 0;
}

.om-nav-link { position: relative; }

.om-nav-icon {
    font-size: 1rem;
    line-height: 1;
    flex-shrink: 0;
}

.om-nav-group {
    margin-top: 0.5rem;
}

.om-nav-group-title {
    display: flex;
    flex-direction: column;
    padding: 0.75rem 0.75rem 0.35rem;
    gap: 0.1rem;
}

.om-nav-chapter-num {
    font-size: 0.7rem;
    color: var(--om-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.om-nav-chapter-name {
    font-size: 0.95rem;
    color: var(--om-heading);
    font-weight: 700;
}

.om-nav-link-chapter {
    padding: 0.4rem 0.75rem;
    font-size: 0.85rem;
    color: var(--om-text-muted);
}

.om-nav-sublist {
    margin-left: 0.5rem;
    padding-left: 0.75rem;
    border-left: 1px solid var(--om-border-light);
    margin-top: 0.2rem;
    margin-bottom: 0.4rem;
}

.om-nav-sublink {
    display: block;
    padding: 0.32rem 0.75rem;
    border-radius: var(--om-radius-sm);
    color: var(--om-text-secondary);
    font-size: 0.83rem;
    transition: all 0.2s ease;
    position: relative;
}

.om-nav-sublink:hover {
    color: var(--om-accent);
    background: var(--om-bg-hover);
}

.om-nav-sublink.active {
    color: var(--om-accent);
    font-weight: 600;
    background: var(--om-accent-soft);
}

.om-nav-divider {
    height: 1px;
    background: var(--om-border-light);
    margin: 0.75rem 0.5rem;
}

.om-nav-footer {
    margin-top: 1.5rem;
    padding: 0.75rem;
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.om-nav-footer-link {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--om-text-muted);
    font-size: 0.8rem;
}

.om-nav-footer-link:hover {
    color: var(--om-accent);
}

.om-nav-version {
    font-size: 0.7rem;
    color: var(--om-text-muted);
}

/* ==========================================================================
   7. Content Typography
   ========================================================================== */

.om-content > :first-child {
    margin-top: 0;
}

.om-content p {
    color: var(--om-text);
    line-height: 1.75;
}

.om-content ul,
.om-content ol {
    margin: 0 0 1.25rem;
    padding-left: 1.5rem;
    color: var(--om-text);
}

.om-content ul li { list-style: disc; margin-bottom: 0.4rem; }
.om-content ol li { list-style: decimal; margin-bottom: 0.4rem; }

.om-content ul li::marker { color: var(--om-accent); }
.om-content ol li::marker { color: var(--om-accent); font-weight: 600; }

.om-content strong {
    color: var(--om-heading);
    font-weight: 700;
}

.om-content em {
    color: var(--om-text-secondary);
    font-style: italic;
}

.om-content a {
    color: var(--om-accent);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.2s ease;
}

.om-content a:hover {
    border-bottom-color: var(--om-accent);
}

.om-content hr {
    border: none;
    height: 1px;
    background: var(--om-border);
    margin: 2.5rem 0;
}

.om-content blockquote {
    margin: 1.5rem 0;
    padding: 1rem 1.25rem;
    border-left: 4px solid var(--om-accent);
    background: var(--om-bg-alt);
    border-radius: 0 var(--om-radius) var(--om-radius) 0;
    color: var(--om-text-secondary);
}

.om-content blockquote p:last-child { margin-bottom: 0; }

.om-content blockquote p {
    color: var(--om-text-secondary);
}

/* Inline code */
.om-content :not(pre) > code {
    padding: 0.15em 0.4em;
    font-size: 0.875em;
    background: var(--om-code-inline-bg);
    border-radius: 4px;
    color: var(--om-accent);
    font-family: "JetBrains Mono", "Fira Code", Consolas, monospace;
    border: 1px solid var(--om-border-light);
}

[data-theme="light"] .om-content :not(pre) > code {
    color: #6d28d9;
}

/* ==========================================================================
   8. Code Block Styles
   ========================================================================== */

.om-code-block {
    position: relative;
    margin: 1.5rem 0;
    border-radius: var(--om-radius);
    overflow: hidden;
    background: var(--om-code-bg);
    border: 1px solid var(--om-code-border);
    box-shadow: var(--om-shadow-sm);
}

.om-code-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.5rem 0.75rem 0.5rem 1rem;
    background: rgba(0, 0, 0, 0.25);
    border-bottom: 1px solid var(--om-code-border);
    font-size: 0.8rem;
}

.om-code-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: #7f849c;
    font-family: "JetBrains Mono", monospace;
}

.om-code-label::before {
    content: "";
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--om-accent);
}

.om-code-lang {
    text-transform: uppercase;
    color: #585b70;
    font-size: 0.7rem;
    letter-spacing: 0.05em;
    margin-left: auto;
    margin-right: 0.75rem;
}

.om-copy-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.3rem 0.6rem;
    border-radius: 4px;
    background: rgba(255, 255, 255, 0.06);
    color: #bac2de;
    font-size: 0.75rem;
    font-family: "JetBrains Mono", monospace;
    transition: all 0.2s ease;
    border: 1px solid transparent;
}

.om-copy-btn:hover {
    background: rgba(255, 255, 255, 0.12);
    color: #fff;
}

.om-copy-btn.copied {
    background: rgba(63, 185, 80, 0.2);
    color: #3fb950;
}

.om-copy-btn svg {
    width: 13px;
    height: 13px;
}

.om-code-block pre {
    margin: 0;
    padding: 1rem 1.25rem;
    background: transparent !important;
    overflow-x: auto;
    font-size: 0.875rem;
    line-height: 1.6;
}

.om-code-block pre code {
    font-family: "JetBrains Mono", "Fira Code", Consolas, monospace;
    background: transparent !important;
    color: var(--om-code-text);
}

/* Plain pre/code without wrapper */
.om-content pre {
    margin: 1.5rem 0;
    padding: 1rem 1.25rem;
    background: var(--om-code-bg);
    border-radius: var(--om-radius);
    border: 1px solid var(--om-code-border);
    overflow-x: auto;
    font-size: 0.875rem;
    line-height: 1.6;
}

.om-content pre code {
    font-family: "JetBrains Mono", "Fira Code", Consolas, monospace;
    background: transparent;
    color: var(--om-code-text);
    padding: 0;
    border: none;
}

/* Prism override to keep dark code bg in both themes */
pre[class*="language-"],
code[class*="language-"] {
    background: transparent !important;
    color: var(--om-code-text);
    text-shadow: none;
    font-family: "JetBrains Mono", "Fira Code", Consolas, monospace !important;
}

/* ==========================================================================
   9. Card / Grid Components
   ========================================================================== */

.om-grid {
    display: grid;
    gap: 1.25rem;
    margin: 1.5rem 0;
}

.om-grid-2 { grid-template-columns: repeat(2, 1fr); }
.om-grid-3 { grid-template-columns: repeat(3, 1fr); }
.om-grid-4 { grid-template-columns: repeat(4, 1fr); }

.om-card {
    background: var(--om-surface);
    border: 1px solid var(--om-border);
    border-radius: var(--om-radius-lg);
    padding: 1.5rem;
    transition: all var(--om-transition);
    position: relative;
    overflow: hidden;
}

.om-card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--om-accent-gradient);
    opacity: 0;
    transition: opacity var(--om-transition);
}

.om-card:hover {
    transform: translateY(-3px);
    border-color: var(--om-accent);
    box-shadow: var(--om-shadow-lg);
}

.om-card:hover::before {
    opacity: 1;
}

.om-card-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    border-radius: var(--om-radius);
    background: var(--om-accent-soft);
    color: var(--om-accent);
    font-size: 1.4rem;
    margin-bottom: 1rem;
}

.om-card-title {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--om-heading);
    margin-bottom: 0.5rem;
}

.om-card-desc {
    font-size: 0.875rem;
    color: var(--om-text-secondary);
    line-height: 1.6;
    margin: 0;
}

.om-card-tag {
    display: inline-block;
    margin-top: 0.75rem;
    padding: 0.2rem 0.6rem;
    font-size: 0.7rem;
    font-family: "JetBrains Mono", monospace;
    background: var(--om-accent-soft);
    color: var(--om-accent);
    border-radius: 4px;
    font-weight: 600;
}

/* Learning path card */
.om-path-card {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    padding: 1.25rem;
    background: var(--om-surface);
    border: 1px solid var(--om-border);
    border-radius: var(--om-radius-lg);
    transition: all var(--om-transition);
}

.om-path-card:hover {
    border-color: var(--om-accent);
    transform: translateX(4px);
    box-shadow: var(--om-shadow);
}

.om-path-number {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--om-accent-gradient);
    color: #fff;
    font-weight: 700;
    font-size: 0.9rem;
}

.om-path-content { flex: 1; min-width: 0; }

.om-path-title {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--om-heading);
    margin-bottom: 0.25rem;
}

.om-path-desc {
    font-size: 0.82rem;
    color: var(--om-text-secondary);
    margin: 0;
}

/* ==========================================================================
   10. Button Styles
   ========================================================================== */

.om-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.65rem 1.4rem;
    border-radius: var(--om-radius);
    font-size: 0.95rem;
    font-weight: 600;
    transition: all var(--om-transition);
    border: 1px solid transparent;
    cursor: pointer;
    line-height: 1.4;
}

.om-btn-primary {
    background: var(--om-accent-gradient);
    color: #fff;
    box-shadow: 0 4px 14px rgba(124, 58, 237, 0.3);
}

.om-btn-primary:hover {
    color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(124, 58, 237, 0.45);
}

.om-btn-secondary {
    background: var(--om-bg-alt);
    color: var(--om-text);
    border-color: var(--om-border);
}

.om-btn-secondary:hover {
    border-color: var(--om-accent);
    color: var(--om-accent);
    transform: translateY(-2px);
}

.om-btn-group {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin: 1.5rem 0;
}

/* ==========================================================================
   11. Mobile Hamburger Menu
   ========================================================================== */

.om-menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 38px;
    height: 38px;
    border-radius: var(--om-radius-sm);
    transition: background var(--om-transition);
}

.om-menu-toggle:hover {
    background: var(--om-bg-hover);
}

.om-menu-toggle-bar {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--om-text);
    border-radius: 2px;
    transition: all var(--om-transition);
}

.om-menu-toggle.active .om-menu-toggle-bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}
.om-menu-toggle.active .om-menu-toggle-bar:nth-child(2) {
    opacity: 0;
}
.om-menu-toggle.active .om-menu-toggle-bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

.om-sidebar-backdrop {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(2px);
    z-index: 998;
    opacity: 0;
    transition: opacity var(--om-transition);
}

.om-sidebar-backdrop.active {
    display: block;
    opacity: 1;
}

/* Back to top */
.om-back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--om-accent);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--om-shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all var(--om-transition);
    z-index: 900;
}

.om-back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.om-back-to-top:hover {
    background: var(--om-accent-hover);
    transform: translateY(-3px);
}

/* ==========================================================================
   12. Scrollbar Styling
   ========================================================================== */

::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--om-bg-alt);
}

::-webkit-scrollbar-thumb {
    background: var(--om-border);
    border-radius: 5px;
    border: 2px solid var(--om-bg-alt);
}

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

.om-sidebar::-webkit-scrollbar {
    width: 6px;
}

.om-sidebar::-webkit-scrollbar-track {
    background: transparent;
}

.om-sidebar::-webkit-scrollbar-thumb {
    background: var(--om-border);
    border: none;
}

/* Firefox */
* {
    scrollbar-width: thin;
    scrollbar-color: var(--om-border) var(--om-bg-alt);
}

/* ==========================================================================
   13. Transitions & Animations
   ========================================================================== */

@keyframes om-fade-in {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes om-spin {
    to { transform: rotate(360deg); }
}

.om-content {
    animation: om-fade-in 0.4s ease;
}

.om-fade-in {
    animation: om-fade-in 0.4s ease;
}

/* ==========================================================================
   14. SVG Container Styles
   ========================================================================== */

.om-svg-container {
    margin: 2rem 0;
    padding: 1.5rem;
    background: var(--om-surface);
    border: 1px solid var(--om-border);
    border-radius: var(--om-radius-lg);
    text-align: center;
}

.om-svg-container svg {
    width: 100%;
    max-width: 720px;
    height: auto;
    margin: 0 auto;
}

.om-svg-caption {
    margin-top: 0.75rem;
    font-size: 0.85rem;
    color: var(--om-text-muted);
    font-style: italic;
}

/* ==========================================================================
   15. Table Styles
   ========================================================================== */

.om-table-wrap {
    overflow-x: auto;
    margin: 1.5rem 0;
    border-radius: var(--om-radius);
    border: 1px solid var(--om-border);
}

.om-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
    background: var(--om-surface);
}

.om-table thead {
    background: var(--om-bg-alt);
}

.om-table th {
    text-align: left;
    padding: 0.85rem 1rem;
    font-weight: 700;
    color: var(--om-heading);
    border-bottom: 2px solid var(--om-border);
    white-space: nowrap;
}

.om-table td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--om-border-light);
    color: var(--om-text);
}

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

.om-table tbody tr {
    transition: background var(--om-transition);
}

.om-table tbody tr:hover {
    background: var(--om-bg-hover);
}

.om-table .om-badge {
    display: inline-block;
    padding: 0.15rem 0.55rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    font-family: "JetBrains Mono", monospace;
    background: var(--om-accent-soft);
    color: var(--om-accent);
}

.om-table .om-badge-success {
    background: rgba(63, 185, 80, 0.15);
    color: var(--om-success);
}

.om-table code {
    font-size: 0.82rem;
    color: var(--om-accent);
    background: var(--om-accent-soft);
    padding: 0.1rem 0.35rem;
    border-radius: 3px;
}

/* ==========================================================================
   16. Callout / Admonition Styles
   ========================================================================== */

.om-callout {
    margin: 1.5rem 0;
    padding: 1rem 1.25rem 1rem 3.25rem;
    border-radius: var(--om-radius);
    border-left: 4px solid;
    position: relative;
    font-size: 0.92rem;
    line-height: 1.7;
}

.om-callout::before {
    content: "";
    position: absolute;
    left: 1.1rem;
    top: 1rem;
    width: 20px;
    height: 20px;
    background-size: contain;
    background-repeat: no-repeat;
}

.om-callout-title {
    font-weight: 700;
    margin-bottom: 0.3rem;
    display: block;
}

.om-callout p:last-child { margin-bottom: 0; }

.om-callout-info {
    background: rgba(88, 166, 255, 0.08);
    border-color: var(--om-info);
    color: var(--om-text);
}

.om-callout-info::before {
    content: "ℹ";
    color: var(--om-info);
    font-size: 1.1rem;
    font-weight: 700;
    line-height: 20px;
    text-align: center;
}

.om-callout-warning {
    background: rgba(210, 153, 34, 0.08);
    border-color: var(--om-warning);
    color: var(--om-text);
}

.om-callout-warning::before {
    content: "⚠";
    color: var(--om-warning);
    font-size: 1rem;
    font-weight: 700;
    line-height: 20px;
    text-align: center;
}

.om-callout-tip {
    background: rgba(63, 185, 80, 0.08);
    border-color: var(--om-success);
    color: var(--om-text);
}

.om-callout-tip::before {
    content: "💡";
    font-size: 1rem;
    line-height: 20px;
}

.om-callout-danger {
    background: rgba(248, 81, 73, 0.08);
    border-color: var(--om-danger);
    color: var(--om-text);
}

.om-callout-danger::before {
    content: "✕";
    color: var(--om-danger);
    font-size: 1rem;
    font-weight: 700;
    line-height: 20px;
    text-align: center;
}

/* ==========================================================================
   17. Utilities & Loading
   ========================================================================== */

.om-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 4rem 1rem;
    color: var(--om-text-muted);
}

.om-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--om-border);
    border-top-color: var(--om-accent);
    border-radius: 50%;
    animation: om-spin 0.8s linear infinite;
    margin-bottom: 1rem;
}

.om-error {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--om-danger);
}

.om-error h2 {
    border: none;
    color: var(--om-danger);
}

.om-hero {
    text-align: center;
    padding: 2rem 0 1rem;
    margin-bottom: 1rem;
}

.om-hero-title {
    font-size: 3rem;
    font-weight: 800;
    background: var(--om-accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
}

.om-hero-subtitle {
    font-size: 1.2rem;
    color: var(--om-text-secondary);
    font-weight: 500;
    margin-bottom: 1rem;
}

.om-hero-desc {
    font-size: 1rem;
    color: var(--om-text-secondary);
    max-width: 600px;
    margin: 0 auto 1.5rem;
    line-height: 1.7;
}

.om-section {
    margin: 3rem 0;
}

.om-section-title {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--om-heading);
    margin-bottom: 0.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--om-border-light);
}

.om-section-subtitle {
    color: var(--om-text-secondary);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
}

/* Prev/Next navigation */
.om-prev-next {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    margin-top: 3rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--om-border);
}

.om-prev-next-link {
    flex: 1;
    max-width: 48%;
    display: flex;
    flex-direction: column;
    padding: 1rem 1.25rem;
    background: var(--om-surface);
    border: 1px solid var(--om-border);
    border-radius: var(--om-radius);
    transition: all var(--om-transition);
    color: var(--om-text);
}

.om-prev-next-link:hover {
    border-color: var(--om-accent);
    color: var(--om-accent);
    transform: translateY(-2px);
}

.om-prev-next-link.om-next {
    text-align: right;
    margin-left: auto;
}

.om-prev-next-label {
    font-size: 0.75rem;
    color: var(--om-text-muted);
    margin-bottom: 0.25rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.om-prev-next-title {
    font-weight: 600;
    font-size: 0.95rem;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */

/* Tablet (768-1024px) */
@media (max-width: 1024px) {
    .om-grid-4 { grid-template-columns: repeat(2, 1fr); }
    .om-grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 769px) {
    .om-sidebar { transform: translateX(0) !important; }
}

/* Mobile (<768px) */
@media (max-width: 768px) {
    :root {
        --om-sidebar-width: 0px;
    }

    .om-menu-toggle {
        display: flex;
    }

    .om-search-hint,
    .om-brand-sub {
        display: none;
    }

    .om-kbd { display: none; }

    .om-search-trigger {
        padding: 0.4rem 0.5rem;
    }

    .om-main {
        margin-left: 0;
    }

    .om-sidebar {
        width: 280px;
        transform: translateX(-100%);
        box-shadow: var(--om-shadow-lg);
    }

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

    .om-content-wrap {
        padding: 1.5rem 1rem 4rem;
    }

    .om-hero-title { font-size: 2.2rem; }
    .om-hero-subtitle { font-size: 1.05rem; }

    h1 { font-size: 1.85rem; }
    h2 { font-size: 1.45rem; }
    h3 { font-size: 1.2rem; }

    .om-grid-2,
    .om-grid-3,
    .om-grid-4 {
        grid-template-columns: 1fr;
    }

    .om-prev-next {
        flex-direction: column;
    }

    .om-prev-next-link,
    .om-prev-next-link.om-next {
        max-width: 100%;
        text-align: left;
        margin-left: 0;
    }

    .om-back-to-top {
        bottom: 1rem;
        right: 1rem;
    }

    .om-topbar-inner {
        padding: 0 1rem;
    }
}

@media (max-width: 480px) {
    .om-hero-title { font-size: 1.8rem; }
    .om-brand-text { font-size: 0.95rem; }
    .om-content-wrap { padding: 1rem 0.85rem 3rem; }
    .om-card { padding: 1.1rem; }
}

/* Print */
@media print {
    .om-topbar,
    .om-sidebar,
    .om-progress-bar,
    .om-back-to-top,
    .om-menu-toggle,
    .om-copy-btn,
    .om-prev-next {
        display: none !important;
    }
    .om-main { margin-left: 0; }
    body { background: #fff; color: #000; }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* ==========================================================================
   18. Search Modal
   ========================================================================== */

.om-search-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 2000;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    opacity: 0;
    transition: opacity 0.2s ease;
}

.om-search-overlay.om-active {
    opacity: 1;
}

.om-search-modal {
    width: 100%;
    max-width: 640px;
    margin-top: 15vh;
    background: var(--om-surface);
    border: 1px solid var(--om-border);
    border-radius: var(--om-radius-lg);
    box-shadow: var(--om-shadow-lg);
    overflow: hidden;
    transform: translateY(-16px);
    transition: transform 0.2s ease;
}

.om-search-overlay.om-active .om-search-modal {
    transform: translateY(0);
}

.om-search-input-wrap {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.85rem 1rem;
    border-bottom: 1px solid var(--om-border);
}

.om-search-icon {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
    color: var(--om-text-muted);
}

#om-search-input {
    flex: 1;
    min-width: 0;
    background: transparent;
    border: none;
    outline: none;
    color: var(--om-text);
    font-size: 1rem;
    font-family: inherit;
    padding: 0.25rem 0;
}

#om-search-input::placeholder {
    color: var(--om-text-muted);
}

.om-search-kbd {
    display: inline-flex;
    align-items: center;
    padding: 0.15rem 0.45rem;
    font-size: 0.7rem;
    font-family: "JetBrains Mono", monospace;
    background: var(--om-bg-elevated);
    border: 1px solid var(--om-border);
    border-radius: 4px;
    color: var(--om-text-secondary);
    flex-shrink: 0;
    line-height: 1.4;
}

.om-search-results {
    max-height: 400px;
    overflow-y: auto;
    padding: 0.5rem;
}

.om-search-hint {
    padding: 2rem 1rem;
    text-align: center;
    color: var(--om-text-muted);
    font-size: 0.9rem;
}

.om-search-hint strong {
    color: var(--om-text);
    font-weight: 600;
}

.om-search-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
    padding: 2rem 1rem;
    color: var(--om-text-muted);
    font-size: 0.9rem;
}

.om-search-loading .om-spinner {
    width: 28px;
    height: 28px;
    border-width: 2px;
    margin: 0;
}

.om-search-error {
    padding: 2rem 1rem;
    text-align: center;
    color: var(--om-danger);
    font-size: 0.9rem;
}

.om-search-result {
    display: block;
    padding: 0.65rem 0.85rem;
    border-radius: var(--om-radius-sm);
    color: var(--om-text);
    transition: background 0.15s ease, border-color 0.15s ease;
    text-decoration: none;
    border: 1px solid transparent;
}

.om-search-result:hover,
.om-search-result.om-active {
    background: var(--om-accent-soft);
    border-color: var(--om-accent);
}

.om-search-result-meta {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.2rem;
}

.om-search-result-page {
    font-size: 0.72rem;
    color: var(--om-accent);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.om-search-result-title {
    font-size: 0.92rem;
    font-weight: 600;
    color: var(--om-heading);
    margin-bottom: 0.25rem;
    line-height: 1.4;
}

.om-search-result-snippet {
    font-size: 0.82rem;
    color: var(--om-text-secondary);
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.om-search-highlight {
    background: var(--om-accent-soft);
    color: var(--om-accent);
    font-weight: 700;
    padding: 0 2px;
    border-radius: 2px;
}

/* Search modal — mobile */
@media (max-width: 768px) {
    .om-search-overlay {
        padding: 0 0.5rem;
    }

    .om-search-modal {
        max-width: 100%;
        margin-top: 1rem;
    }
}

/* Hide search overlay when printing */
@media print {
    .om-search-overlay {
        display: none !important;
    }
}