:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --text-tertiary: #868e96;
    --border-color: #dee2e6;
    --code-bg: #f6f8fa;
    --code-border: #e1e4e8;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-lg: rgba(0, 0, 0, 0.15);
    --hover-bg: #e9ecef;
    --sidebar-width: 280px;
    --accent-color: #212529;
}

[data-theme="dark"] {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-tertiary: #6e7681;
    --border-color: #30363d;
    --code-bg: #161b22;
    --code-border: #30363d;
    --shadow: rgba(0, 0, 0, 0.3);
    --shadow-lg: rgba(0, 0, 0, 0.5);
    --hover-bg: #21262d;
    --accent-color: #e6edf3;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
    overflow: hidden;
}

.container {
    display: flex;
    height: 100vh;
    overflow: hidden;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    min-width: var(--sidebar-width);
    background-color: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    transition: all 0.3s ease;
    position: relative;
    z-index: 100;
    flex-shrink: 0;
}

.sidebar.collapsed {
    width: 0;
    min-width: 0;
    border-right: none;
    overflow: hidden;
}

.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-secondary);
    flex-shrink: 0;
}

.logo h1 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    white-space: nowrap;
    margin-bottom: 16px;
}

.header-actions {
    display: flex;
    gap: 8px;
}

.icon-btn {
    background: none;
    border: 1px solid var(--border-color);
    cursor: pointer;
    padding: 10px;
    border-radius: 12px;
    transition: all 0.2s;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    font-size: 1.1rem;
    line-height: 1;
    flex: 1;
}

.icon-btn:hover {
    background-color: var(--hover-bg);
    color: var(--text-primary);
    border-color: var(--text-secondary);
}

.double-btn {
    display: flex;
    gap: 4px;
    flex: 1;
}

.double-btn .icon-btn {
    flex: 1;
    padding: 10px 8px;
}

/* Search */
.search-box {
    padding: 16px 20px;
    position: relative;
    flex-shrink: 0;
}

#searchInput {
    width: 100%;
    padding: 10px 36px 10px 12px;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 0.9rem;
    transition: border-color 0.2s;
}

#searchInput:focus {
    outline: none;
    border-color: var(--text-primary);
    background-color: var(--hover-bg);
}

/* Navigation */
.nav {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    padding: 12px 0;
}

.nav ul {
    list-style: none;
}

.nav li {
    margin: 2px 0;
}

.nav a {
    display: block;
    padding: 10px 20px;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.2s;
    border-left: 3px solid transparent;
    font-size: 0.9rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

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

.nav a.active {
    color: var(--text-primary);
    background-color: var(--hover-bg);
    font-weight: 500;
}

.nav .folder {
    padding: 10px 20px;
    color: var(--text-primary);
    cursor: pointer;
    user-select: none;
    font-size: 0.9rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 8px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.nav .folder::before {
    content: '▸';
    font-size: 0.8rem;
    transition: transform 0.2s;
    flex-shrink: 0;
}

.nav .folder.open::before {
    transform: rotate(90deg);
}

.nav .folder:hover {
    background-color: var(--hover-bg);
}

.nav .nested {
    padding-left: 16px;
    display: none;
}

.nav .nested.open {
    display: block;
}

/* Content */
.content {
    flex: 1;
    display: flex;
    overflow: hidden;
    position: relative;
    min-width: 0;
}

.content-wrapper {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    display: flex;
    justify-content: center;
    min-width: 0;
}

.menu-toggle {
    display: none;
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 200;
    flex-direction: column;
    gap: 4px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    cursor: pointer;
    padding: 10px;
    box-shadow: 0 2px 8px var(--shadow);
}

.menu-toggle span {
    width: 20px;
    height: 2px;
    background-color: var(--text-primary);
    transition: all 0.3s;
}

.expand-btn {
    display: none;
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 90;
    padding: 12px 16px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    cursor: pointer;
    color: var(--text-secondary);
    transition: all 0.2s;
    box-shadow: 0 2px 8px var(--shadow);
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.sidebar.collapsed ~ .content .expand-btn {
    display: flex;
}

.expand-btn:hover {
    background-color: var(--hover-bg);
    color: var(--text-primary);
}

#mainContent {
    width: 100%;
    max-width: 900px;
    padding: 40px;
}

/* Table of Contents */
.toc {
    width: 280px;
    min-width: 280px;
    padding: 40px 20px;
    border-left: 1px solid var(--border-color);
    overflow-y: auto;
    overflow-x: hidden;
    background-color: var(--bg-secondary);
    display: none;
    flex-shrink: 0;
    position: relative;
}

.toc.visible {
    display: block;
}

.toc.collapsed {
    display: none;
}

.toc-header {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.toc nav {
    font-size: 0.85rem;
}

.toc a {
    display: block;
    color: var(--text-secondary);
    text-decoration: none;
    padding: 6px 0;
    padding-left: 12px;
    border-left: 2px solid transparent;
    transition: all 0.2s;
    word-wrap: break-word;
}

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

.toc a.active {
    color: var(--text-primary);
    border-left-color: var(--text-primary);
    font-weight: 500;
}

.toc a.level-3 {
    padding-left: 24px;
}

/* Expand TOC button */
.expand-toc-btn {
    display: none;
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 90;
    padding: 12px 16px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    cursor: pointer;
    color: var(--text-secondary);
    transition: all 0.2s;
    box-shadow: 0 2px 8px var(--shadow);
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.toc.collapsed ~ .expand-toc-btn {
    display: flex;
}

.expand-toc-btn:hover {
    background-color: var(--hover-bg);
    color: var(--text-primary);
}

.ai-summary {
    margin-top: 24px;
    padding-top: 24px;
}

.ai-summary-header {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 6px;
}

.ai-summary-header .icon {
    font-size: 1rem;
}

.ai-summary-content {
    font-size: 0.85rem;
    line-height: 1.6;
    color: var(--text-secondary);
    padding: 12px;
    background-color: var(--bg-tertiary);
    border-radius: 12px;

}

[data-theme="dark"] .ai-summary-content {
    background: linear-gradient(135deg, rgba(255, 215, 0, 0.15) 0%, rgba(255, 165, 0, 0.08) 100%);
}

.ai-summary-content p {
    margin-bottom: 8px;
}

.ai-summary-content p:last-child {
    margin-bottom: 0;
}

/* Markdown Styles */
.markdown-body {
    color: var(--text-primary);
    font-size: 16px;
    line-height: 1.7;
}

.markdown-body h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
    line-height: 1.2;
    letter-spacing: -0.02em;
}

.markdown-body h2 {
    font-size: 2rem;
    font-weight: 600;
    margin-top: 3rem;
    margin-bottom: 1rem;
    padding-bottom: 0.3rem;
    border-bottom: 1px solid var(--border-color);
    line-height: 1.3;
    letter-spacing: -0.01em;
}

.markdown-body h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-top: 2rem;
    margin-bottom: 0.8rem;
    line-height: 1.4;
}

.markdown-body h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-top: 1.5rem;
    margin-bottom: 0.6rem;
}

.markdown-body h5 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-top: 1.2rem;
    margin-bottom: 0.5rem;
}

.markdown-body h6 {
    font-size: 1rem;
    font-weight: 600;
    margin-top: 1rem;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

.markdown-body p {
    margin-bottom: 1.2rem;
    line-height: 1.7;
}

.markdown-body ul, .markdown-body ol {
    margin-bottom: 1.2rem;
    padding-left: 2rem;
}

.markdown-body li {
    margin-bottom: 0.5rem;
    line-height: 1.7;
}

.markdown-body ul ul, .markdown-body ol ol {
    margin-top: 0.5rem;
    margin-bottom: 0.5rem;
}

.markdown-body code {
    background-color: var(--code-bg);
    color: var(--text-primary);
    padding: 3px 8px;
    border-radius: 6px;
    font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Fira Code', 'Consolas', 'Liberation Mono', 'Courier New', monospace;
    font-size: 0.9em;
    border: 1px solid var(--code-border);
    font-weight: 400;
}

.markdown-body pre {
    background-color: var(--code-bg);
    padding: 20px;
    border-radius: 12px;
    overflow-x: auto;
    margin: 1.5rem 0;
    border: 1px solid var(--code-border);
    line-height: 1.6;
    box-shadow: 0 1px 3px var(--shadow);
}

.markdown-body pre code {
    background: none;
    padding: 0;
    border: none;
    font-size: 0.9rem;
    display: block;
}

.markdown-body blockquote {
    border-left: 4px solid var(--border-color);
    padding: 0.8rem 1.2rem;
    margin: 1.5rem 0;
    color: var(--text-secondary);
    background-color: var(--bg-secondary);
    border-radius: 0 12px 12px 0;
}

.markdown-body blockquote p {
    margin-bottom: 0.5rem;
}

.markdown-body blockquote p:last-child {
    margin-bottom: 0;
}

.markdown-body a {
    color: var(--text-primary);
    text-decoration: underline;
    text-decoration-color: var(--text-secondary);
    text-decoration-thickness: 1px;
    text-underline-offset: 2px;
    transition: text-decoration-color 0.2s;
}

.markdown-body a:hover {
    text-decoration-color: var(--text-primary);
}

.markdown-body img {
    max-width: 100%;
    height: auto;
    border-radius: 12px;
    margin: 1.5rem 0;
    box-shadow: 0 4px 12px var(--shadow);
}

.markdown-body hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 3rem 0;
}

.markdown-body table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    font-size: 0.9rem;
    overflow: hidden;
    border-radius: 12px;
    box-shadow: 0 1px 3px var(--shadow);
}

.markdown-body th, .markdown-body td {
    border: 1px solid var(--border-color);
    padding: 12px 16px;
    text-align: left;
}

.markdown-body th {
    background-color: var(--bg-secondary);
    font-weight: 600;
    color: var(--text-primary);
}

.markdown-body tr:nth-child(even) {
    background-color: var(--bg-secondary);
}

.markdown-body tr:hover {
    background-color: var(--hover-bg);
}

.markdown-body strong {
    font-weight: 600;
    color: var(--text-primary);
}

.markdown-body em {
    font-style: italic;
}

/* Code syntax highlighting colors */
.keyword { color: #d73a49; font-weight: 500; }
.string { color: #22863a; }
.comment { color: #6a737d; font-style: italic; }
.function { color: #6f42c1; }
.number { color: #005cc5; }
.tag { color: #22863a; font-weight: 500; }
.attr { color: #6f42c1; }

[data-theme="dark"] .keyword { color: #ff7b72; }
[data-theme="dark"] .string { color: #a5d6ff; }
[data-theme="dark"] .comment { color: #8b949e; }
[data-theme="dark"] .function { color: #d2a8ff; }
[data-theme="dark"] .number { color: #79c0ff; }
[data-theme="dark"] .tag { color: #7ee787; }
[data-theme="dark"] .attr { color: #d2a8ff; }

/* Responsive */
@media (max-width: 1200px) {
    .toc {
        position: fixed;
        right: 0;
        top: 0;
        height: 100vh;
        z-index: 150;
        transform: translateX(100%);
        box-shadow: -2px 0 16px var(--shadow-lg);
        width: 280px;
        min-width: 280px;
        display: block;
        transition: transform 0.3s ease;
    }

    .toc.visible {
        display: block;
    }

    .toc.visible:not(.collapsed) {
        transform: translateX(0);
    }

    .toc.collapsed {
        transform: translateX(100%);
    }

    .expand-toc-btn {
        display: flex;
    }

    .toc.visible:not(.collapsed) ~ .expand-toc-btn {
        display: none;
    }
}

@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        left: 0;
        top: 0;
        height: 100vh;
        z-index: 150;
        transform: translateX(-100%);
        box-shadow: 2px 0 16px var(--shadow-lg);
        width: var(--sidebar-width);
        min-width: var(--sidebar-width);
    }

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

    .sidebar.collapsed {
        transform: translateX(-100%);
        width: var(--sidebar-width);
        min-width: var(--sidebar-width);
    }

    .menu-toggle {
        display: flex;
    }

    .expand-btn {
        display: none !important;
    }

    #mainContent {
        padding: 80px 20px 24px 20px;
    }

    .expand-toc-btn {
        top: 70px;
        right: 20px;
    }

    .markdown-body h1 {
        font-size: 2rem;
    }

    .markdown-body h2 {
        font-size: 1.6rem;
    }

    .markdown-body h3 {
        font-size: 1.3rem;
    }

    .markdown-body pre {
        padding: 16px;
        border-radius: 12px;
    }
}

/* Print styles */
@media print {
    .sidebar, .menu-toggle, .toc, .expand-btn, .expand-toc-btn {
        display: none !important;
    }

    .content {
        overflow: visible;
    }

    .content-wrapper {
        overflow: visible;
    }

    #mainContent {
        max-width: none;
        padding: 0;
    }

    .markdown-body a {
        text-decoration: none;
        color: var(--text-primary);
    }

    .markdown-body pre {
        page-break-inside: avoid;
    }
}

/* Scrollbar */
.nav::-webkit-scrollbar,
.toc::-webkit-scrollbar,
.content-wrapper::-webkit-scrollbar {
    width: 4px;
    height: 4px;
}

.nav::-webkit-scrollbar-track,
.toc::-webkit-scrollbar-track,
.content-wrapper::-webkit-scrollbar-track {
    background: transparent;
}

.nav::-webkit-scrollbar-thumb,
.toc::-webkit-scrollbar-thumb,
.content-wrapper::-webkit-scrollbar-thumb {
    background: var(--border-color);

}

.nav::-webkit-scrollbar-thumb:hover,
.toc::-webkit-scrollbar-thumb:hover,
.content-wrapper::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Selection */
::selection {
    background-color: var(--text-primary);
    color: var(--bg-primary);
}

/* Focus styles */
*:focus-visible {
    outline: 2px solid var(--text-primary);
    outline-offset: 2px;
}