/* CSS Variables */
:root {
    --header-height: 3.5rem;
    --sidebar-width: 280px;
    --toc-width: 200px;
    --content-max-width: 800px;
    --transition-speed: 0.3s;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Open Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    min-height: 100vh;
}

/* Skip Link for Accessibility */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--color-primary);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    text-decoration: none;
    border-radius: 0 0 var(--radius-md) 0;
    z-index: 1000;
    font-weight: 600;
}

.skip-link:focus {
    top: 0;
}

/* Focus Styles */
*:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

*:focus:not(:focus-visible) {
    outline: none;
}

*:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    display: flex;
    align-items: center;
    padding: 0 var(--spacing-lg);
    z-index: 100;
    gap: var(--spacing-md);
    
    /* Modern glassmorphism effect */
    background: var(--color-bg-primary);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
    
    transition: all var(--transition-base);
}

.logo {
    font-size: 1.25rem;
    font-weight: 600;
    font-family: 'Poppins', sans-serif;
    text-decoration: none;
    color: var(--color-text-primary);
    transition: color var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.logo:hover {
    color: var(--color-primary);
}

.header-right {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-left: auto;
}

/* Menu Toggle (Mobile) */
.menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-around;
    width: 1.5rem;
    height: 1.25rem;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    position: relative;
}

.menu-toggle span {
    width: 100%;
    height: 2px;
    background: var(--color-text-primary);
    border-radius: var(--radius-sm);
    transition: all var(--transition-base);
    transform-origin: center;
}

.menu-toggle.active span:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}

.menu-toggle.active span:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
}

/* Search Box */
.search-box {
    position: relative;
    display: flex;
    align-items: center;
}

.search-icon {
    position: absolute;
    left: var(--spacing-md);
    color: var(--color-text-tertiary);
    pointer-events: none;
    z-index: 1;
}

.search-box input {
    width: 200px;
    padding: var(--spacing-sm) var(--spacing-md);
    padding-left: 2.5rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    outline: none;
    background: var(--color-bg-secondary);
    color: var(--color-text-primary);
    transition: all var(--transition-base);
}

.search-box input::placeholder {
    color: var(--color-text-tertiary);
}

.search-box input:focus {
    border-color: var(--color-primary);
    background: var(--color-bg-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
    width: 240px;
}

.search-results {
    position: absolute;
    top: calc(100% + var(--spacing-sm));
    left: 0;
    right: 0;
    max-height: 400px;
    overflow-y: auto;
    background: var(--color-bg-primary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    display: none;
    z-index: 200;
    animation: slideDown var(--transition-base) ease-out;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.search-results.active {
    display: block;
}

.search-result-item {
    padding: var(--spacing-md);
    cursor: pointer;
    transition: background var(--transition-fast);
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text-primary);
}

.search-result-item:last-child {
    border-bottom: none;
}

.search-result-item:hover {
    background: var(--color-bg-secondary);
}

.search-result-item mark {
    background: rgba(249, 115, 22, 0.2);
    color: var(--color-accent);
    padding: 0.1rem 0.2rem;
    border-radius: var(--radius-sm);
    font-weight: 500;
}

/* Language Select */
.lang-select {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    cursor: pointer;
    outline: none;
    background: var(--color-bg-secondary);
    color: var(--color-text-primary);
    transition: all var(--transition-fast);
}

.lang-select:hover {
    border-color: var(--color-border-hover);
}

.lang-select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* Theme Toggle */
.theme-toggle {
    background: transparent;
    border: none;
    font-size: 1.25rem;
    cursor: pointer;
    padding: var(--spacing-sm);
    color: var(--color-text-primary);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background: var(--color-bg-secondary);
    color: var(--color-primary);
}

.theme-toggle svg {
    transition: transform var(--transition-base);
}

.theme-toggle:hover svg {
    transform: rotate(20deg);
}

/* Container Layout */
.container {
    display: flex;
    margin-top: var(--header-height);
    min-height: calc(100vh - var(--header-height));
}

/* Sidebar */
.sidebar {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: var(--sidebar-width);
    height: calc(100vh - var(--header-height));
    overflow-y: auto;
    padding: var(--spacing-xl) var(--spacing-md);
    transition: transform var(--transition-slow);
    z-index: 50;
    background: var(--color-bg-secondary);
    border-right: 1px solid var(--color-border);
}

/* Custom scrollbar for sidebar */
.sidebar::-webkit-scrollbar {
    width: 6px;
}

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

.sidebar::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: var(--radius-full);
}

.sidebar::-webkit-scrollbar-thumb:hover {
    background: var(--color-border-hover);
}

.sidebar-nav a {
    display: block;
    padding: var(--spacing-sm) var(--spacing-md);
    text-decoration: none;
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    transition: all var(--transition-base);
    position: relative;
}

.sidebar-nav a:hover {
    background: var(--color-bg-tertiary);
    color: var(--color-text-primary);
    transform: translateX(2px);
}

.sidebar-nav a.active {
    background: var(--color-primary);
    color: white;
    font-weight: 600;
    box-shadow: var(--shadow-sm);
}

.sidebar-nav a.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 60%;
    background: white;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.sidebar-nav .folder-title {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-sm) var(--spacing-md);
    font-weight: 500;
    cursor: pointer;
    user-select: none;
    border-radius: var(--radius-md);
    color: var(--color-text-primary);
    transition: all var(--transition-fast);
}

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

.sidebar-nav .folder-title::after {
    content: '▼';
    font-size: 0.6rem;
    color: var(--color-text-tertiary);
    transition: transform var(--transition-base);
}

.sidebar-nav .folder.collapsed .folder-title::after {
    transform: rotate(-90deg);
}

.sidebar-nav .folder-children {
    padding-left: var(--spacing-md);
    overflow: hidden;
    transition: max-height var(--transition-slow) ease-in-out, opacity var(--transition-base);
    opacity: 1;
}

.sidebar-nav .folder.collapsed .folder-children {
    max-height: 0 !important;
    opacity: 0;
}

.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 40;
    backdrop-filter: blur(2px);
    animation: fadeIn var(--transition-base);
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

/* Main Content */
.content {
    flex: 1;
    display: flex;
    margin-left: var(--sidebar-width);
    padding: var(--spacing-2xl);
    gap: var(--spacing-2xl);
}

.doc-content {
    flex: 1;
    max-width: var(--content-max-width);
    min-width: 0;
    line-height: 1.7;
    color: var(--color-text-primary);
}

/* TOC */
.toc {
    width: var(--toc-width);
    position: sticky;
    top: calc(var(--header-height) + 2rem);
    max-height: calc(100vh - var(--header-height) - 4rem);
    overflow-y: auto;
    font-size: 0.85rem;
    padding-left: var(--spacing-lg);
    border-left: 2px solid var(--color-border);
}

.toc-title {
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--color-text-primary);
}

.toc a {
    display: block;
    padding: var(--spacing-xs) 0;
    text-decoration: none;
    color: var(--color-text-tertiary);
    transition: color var(--transition-fast);
}

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

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

.toc a.toc-h3 {
    padding-left: var(--spacing-md);
    font-size: 0.8125rem;
}

/* Document Styles */
.doc-content h1 {
    font-size: 2.25rem;
    font-weight: 700;
    font-family: 'Poppins', sans-serif;
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--color-border);
    color: var(--color-text-primary);
    line-height: 1.2;
}

.doc-content h2 {
    font-size: 1.875rem;
    font-weight: 600;
    font-family: 'Poppins', sans-serif;
    margin: 2.5rem 0 var(--spacing-lg);
    color: var(--color-text-primary);
    line-height: 1.3;
}

.doc-content h3 {
    font-size: 1.5rem;
    font-weight: 600;
    font-family: 'Poppins', sans-serif;
    margin: 2rem 0 var(--spacing-md);
    color: var(--color-text-primary);
    line-height: 1.4;
}

.doc-content h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin: var(--spacing-xl) 0 var(--spacing-sm);
    color: var(--color-text-primary);
}

.doc-content p {
    margin-bottom: 1.25rem;
    color: var(--color-text-secondary);
}

.doc-content a {
    text-decoration: none;
    color: var(--color-primary);
    transition: color var(--transition-fast);
    border-bottom: 1px solid transparent;
}

.doc-content a:hover {
    color: var(--color-primary-hover);
    border-bottom-color: var(--color-primary-hover);
}

.doc-content ul, .doc-content ol {
    margin-bottom: var(--spacing-lg);
    padding-left: var(--spacing-xl);
    color: var(--color-text-secondary);
}

.doc-content li {
    margin-bottom: var(--spacing-sm);
    line-height: 1.7;
}

.doc-content li::marker {
    color: var(--color-primary);
}

.doc-content code {
    padding: 0.2rem 0.4rem;
    border-radius: var(--radius-sm);
    font-family: 'Fira Code', 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
    font-size: 0.875em;
    background: var(--color-bg-tertiary);
    color: var(--color-accent);
    font-weight: 500;
}

.doc-content pre {
    margin-bottom: var(--spacing-xl);
    padding: 1.25rem;
    border-radius: var(--radius-lg);
    overflow-x: auto;
    background: var(--color-bg-tertiary);
    border: 1px solid var(--color-border);
    font-family: 'Fira Code', 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
    font-size: 0.875rem;
    line-height: 1.6;
}

.doc-content pre code {
    padding: 0;
    background: transparent;
    color: inherit;
    font-weight: normal;
}

.doc-content blockquote {
    margin: var(--spacing-lg) 0;
    padding: var(--spacing-md) var(--spacing-lg);
    border-left: 4px solid var(--color-primary);
    background: var(--color-bg-secondary);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    color: var(--color-text-secondary);
}

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

.doc-content table {
    width: 100%;
    margin-bottom: var(--spacing-xl);
    border-collapse: separate;
    border-spacing: 0;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.doc-content th {
    background: var(--color-bg-tertiary);
    font-weight: 600;
    text-align: left;
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: 2px solid var(--color-border);
    color: var(--color-text-primary);
}

.doc-content td {
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text-secondary);
}

.doc-content tr:last-child td {
    border-bottom: none;
}

.doc-content tbody tr {
    transition: background var(--transition-fast);
}

.doc-content tbody tr:hover {
    background: var(--color-bg-secondary);
}

/* Anchor Links */
.doc-content h1[id], .doc-content h2[id], .doc-content h3[id] {
    scroll-margin-top: calc(var(--header-height) + 1rem);
}

.anchor-link {
    opacity: 0;
    margin-left: 0.5rem;
    text-decoration: none;
    transition: opacity var(--transition-speed);
}

.doc-content h1:hover .anchor-link,
.doc-content h2:hover .anchor-link,
.doc-content h3:hover .anchor-link {
    opacity: 0.5;
}

/* Loading & Error States */
.loading {
    text-align: center;
    padding: 3rem;
    opacity: 0.6;
}

.not-found {
    text-align: center;
    padding: 4rem 2rem;
}

.not-found h1 {
    font-size: 4rem;
    margin-bottom: 1rem;
    border: none;
}

.not-found a {
    display: inline-block;
    margin-top: 1rem;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    text-decoration: none;
}

/* Search Highlight */
mark {
    padding: 0.1rem 0.2rem;
    border-radius: 2px;
}

/* Responsive Design */
@media (max-width: 1280px) {
    .toc {
        display: none;
    }
}

@media (max-width: 1024px) {
    :root {
        --sidebar-width: 240px;
    }
}

@media (max-width: 768px) {
    .menu-toggle {
        display: flex;
    }
    
    .search-box input {
        width: 120px;
    }
    
    .search-box input:focus {
        width: 160px;
    }
    
    .sidebar {
        transform: translateX(-100%);
        box-shadow: none;
    }
    
    .sidebar.open {
        transform: translateX(0);
        box-shadow: var(--shadow-xl);
    }
    
    .sidebar-overlay.active {
        display: block;
    }
    
    /* Prevent body scroll when menu is open */
    body.menu-open {
        overflow: hidden;
    }
    
    .content {
        margin-left: 0;
        padding: var(--spacing-xl) var(--spacing-md);
    }
    
    .doc-content h1 {
        font-size: 1.75rem;
    }
    
    .doc-content h2 {
        font-size: 1.35rem;
    }
    
    .doc-content pre {
        margin-left: calc(-1 * var(--spacing-md));
        margin-right: calc(-1 * var(--spacing-md));
        border-radius: 0;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 0 var(--spacing-md);
    }
    
    .header-right {
        gap: var(--spacing-sm);
    }
    
    .search-box input {
        width: 100px;
    }
    
    .search-box input:focus {
        width: 140px;
    }
    
    .lang-select {
        padding: var(--spacing-xs) var(--spacing-sm);
        font-size: 0.8rem;
    }
    
    .logo {
        font-size: 1.1rem;
    }
}

/* Touch-friendly */
@media (hover: none) {
    .anchor-link {
        opacity: 0.3;
    }
    
    /* Larger touch targets on mobile */
    .sidebar-nav a,
    .sidebar-nav .folder-title {
        padding: var(--spacing-md);
    }
}