/* ===================================
   机械制图知识库 - 样式文件
   Mechanical Drawing Knowledge Base
   =================================== */

/* CSS Variables */
:root {
    /* Colors - Light Theme */
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #3b82f6;
    --color-bg: #f8fafc;
    --color-bg-secondary: #f1f5f9;
    --color-surface: #ffffff;
    --color-text: #1e293b;
    --color-text-secondary: #64748b;
    --color-text-muted: #94a3b8;
    --color-border: #e2e8f0;
    --color-border-light: #f1f5f9;
    --color-code-bg: #f1f5f9;
    --color-shadow: rgba(0, 0, 0, 0.1);
    --color-hover: #eff6ff;
    --color-card-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
    --font-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, "Courier New", monospace;
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
    
    /* Sidebar */
    --sidebar-width: 280px;
    --header-height: 60px;
}

/* Dark Theme */
[data-theme="dark"] {
    --color-bg: #0f172a;
    --color-bg-secondary: #1e293b;
    --color-surface: #1e293b;
    --color-text: #f1f5f9;
    --color-text-secondary: #94a3b8;
    --color-text-muted: #64748b;
    --color-border: #334155;
    --color-border-light: #1e293b;
    --color-code-bg: #1e293b;
    --color-shadow: rgba(0, 0, 0, 0.3);
    --color-hover: #1e293b;
    --color-card-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--header-height) + var(--spacing-lg));
}

body {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Header */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--spacing-lg);
    z-index: 1000;
    transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.header-content {
    display: flex;
    align-items: baseline;
    gap: var(--spacing-md);
}

.site-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-primary);
}

.site-subtitle {
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.theme-toggle {
    width: 40px;
    height: 40px;
    border: none;
    background: transparent;
    cursor: pointer;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-secondary);
    transition: background-color var(--transition-fast), color var(--transition-fast);
}

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

.theme-toggle .icon-moon {
    display: none;
}

[data-theme="dark"] .icon-sun {
    display: none;
}

[data-theme="dark"] .icon-moon {
    display: block;
}

/* Search */
.search-container {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md) var(--spacing-lg);
    z-index: 999;
    display: none;
    transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

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

.search-wrapper {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    gap: var(--spacing-sm);
}

.search-wrapper input {
    flex: 1;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 1rem;
    background: var(--color-bg);
    color: var(--color-text);
    transition: background-color var(--transition-normal), border-color var(--transition-fast);
}

.search-wrapper input:focus {
    outline: none;
    border-color: var(--color-primary);
}

.search-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-primary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background-color var(--transition-fast);
}

.search-btn:hover {
    background: var(--color-primary-dark);
}

.search-results {
    max-width: 800px;
    margin: var(--spacing-md) auto 0;
    max-height: 400px;
    overflow-y: auto;
    display: none;
}

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

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

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

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

.search-result-title {
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.search-result-preview {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

/* Main Container */
.main-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));
    background: var(--color-surface);
    border-right: 1px solid var(--color-border);
    overflow-y: auto;
    padding: var(--spacing-lg) 0;
    transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.nav-section {
    margin-bottom: var(--spacing-lg);
}

.nav-title {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    padding: 0 var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.nav-list {
    list-style: none;
}

.nav-link {
    display: block;
    padding: var(--spacing-sm) var(--spacing-lg);
    color: var(--color-text-secondary);
    text-decoration: none;
    font-size: 0.9375rem;
    border-left: 3px solid transparent;
    transition: all var(--transition-fast);
}

.nav-link:hover {
    background: var(--color-hover);
    color: var(--color-primary);
}

.nav-link.active {
    background: var(--color-hover);
    color: var(--color-primary);
    border-left-color: var(--color-primary);
    font-weight: 500;
}

/* Content Area */
.content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: var(--spacing-xl);
    max-width: 100%;
    overflow-x: hidden;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: var(--spacing-2xl) 0;
    margin-bottom: var(--spacing-xl);
}

.hero h2 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
}

.hero p {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
}

/* Features Grid */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.feature-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    transition: all var(--transition-normal);
}

.feature-card:hover {
    box-shadow: var(--color-card-shadow);
    transform: translateY(-2px);
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: var(--spacing-md);
}

.feature-card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
}

.feature-card p {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    line-height: 1.5;
}

/* Quick Links */
.quick-links {
    margin-bottom: var(--spacing-xl);
}

.quick-links h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-lg);
}

.link-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
}

.quick-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    text-decoration: none;
    transition: all var(--transition-fast);
}

.quick-link:hover {
    border-color: var(--color-primary);
    background: var(--color-hover);
}

.link-icon {
    font-size: 1.5rem;
}

.link-text {
    font-size: 0.9375rem;
    color: var(--color-text);
    font-weight: 500;
}

/* Info Section */
.info-section {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
}

.info-section h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-lg);
}

.info-content {
    color: var(--color-text-secondary);
    line-height: 1.7;
}

.info-content ul {
    margin: var(--spacing-md) 0;
    padding-left: var(--spacing-lg);
}

.info-content li {
    margin-bottom: var(--spacing-sm);
}

.info-content strong {
    color: var(--color-text);
}

/* Page Content Styles */
.page-header {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
}

.page-header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
}

.page-header .subtitle {
    font-size: 1rem;
    color: var(--color-text-muted);
}

.content-section {
    margin-bottom: var(--spacing-xl);
}

.content-section h2 {
    font-size: 1.375rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--color-primary);
    display: inline-block;
}

.content-section h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-text);
    margin: var(--spacing-lg) 0 var(--spacing-md);
}

.content-section p {
    margin-bottom: var(--spacing-md);
    color: var(--color-text-secondary);
    line-height: 1.7;
}

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

.content-section li {
    margin-bottom: var(--spacing-sm);
    line-height: 1.6;
}

/* Definition Lists */
.definition-list {
    margin-bottom: var(--spacing-lg);
}

.definition-item {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--color-border-light);
}

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

.definition-term {
    min-width: 120px;
    font-weight: 600;
    color: var(--color-text);
}

.definition-desc {
    color: var(--color-text-secondary);
    flex: 1;
}

/* Tables */
.table-container {
    overflow-x: auto;
    margin-bottom: var(--spacing-lg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

th, td {
    padding: var(--spacing-md);
    text-align: left;
    border-bottom: 1px solid var(--color-border);
}

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

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

tr:hover td {
    background: var(--color-hover);
}

/* Code Blocks */
.code-block {
    background: var(--color-code-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    overflow-x: auto;
}

.code-block pre {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    line-height: 1.5;
    color: var(--color-text);
    margin: 0;
}

.code-block code {
    font-family: var(--font-mono);
}

/* Diagrams / Figures */
.figure {
    margin: var(--spacing-lg) 0;
    text-align: center;
}

.figure-container {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

.figure-caption {
    font-size: 0.875rem;
    color: var(--color-text-muted);
    font-style: italic;
}

/* Cards */
.card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    transition: all var(--transition-fast);
}

.card:hover {
    box-shadow: var(--color-card-shadow);
}

.card-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.card-icon {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.card-content {
    color: var(--color-text-secondary);
    font-size: 0.9375rem;
    line-height: 1.6;
}

/* Info Box */
.info-box {
    background: var(--color-bg-secondary);
    border-left: 4px solid var(--color-primary);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    margin: var(--spacing-lg) 0;
}

.info-box.warning {
    border-left-color: #f59e0b;
    background: #fffbeb;
}

.info-box.danger {
    border-left-color: #ef4444;
    background: #fef2f2;
}

.info-box.success {
    border-left-color: #10b981;
    background: #ecfdf5;
}

[data-theme="dark"] .info-box.warning {
    background: rgba(245, 158, 11, 0.1);
}

[data-theme="dark"] .info-box.danger {
    background: rgba(239, 68, 68, 0.1);
}

[data-theme="dark"] .info-box.success {
    background: rgba(16, 185, 129, 0.1);
}

/* Back to Top */
.back-to-top {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    width: 48px;
    height: 48px;
    background: var(--color-primary);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
    z-index: 998;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: var(--color-primary-dark);
    transform: translateY(-2px);
}

/* Responsive Design */
@media (max-width: 1024px) {
    .sidebar {
        transform: translateX(-100%);
        z-index: 997;
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .content {
        margin-left: 0;
    }
    
    .menu-toggle {
        display: flex;
    }
}

@media (max-width: 768px) {
    :root {
        --header-height: 56px;
    }
    
    .site-title {
        font-size: 1rem;
    }
    
    .site-subtitle {
        display: none;
    }
    
    .content {
        padding: var(--spacing-md);
    }
    
    .hero h2 {
        font-size: 1.5rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .features {
        grid-template-columns: 1fr;
    }
    
    .link-grid {
        grid-template-columns: 1fr;
    }
    
    .definition-item {
        flex-direction: column;
    }
    
    .definition-term {
        min-width: auto;
    }
}

/* Mobile Menu Toggle */
.menu-toggle {
    display: none;
    width: 40px;
    height: 40px;
    background: transparent;
    border: none;
    cursor: pointer;
    align-items: center;
    justify-content: center;
    color: var(--color-text);
    position: fixed;
    top: 8px;
    left: var(--spacing-md);
    z-index: 1001;
}

@media (max-width: 1024px) {
    .menu-toggle {
        display: flex;
    }
    
    .site-header {
        padding-left: 60px;
    }
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--color-bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: 4px;
}

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

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

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.content-section {
    animation: fadeIn 0.3s ease;
}

/* Print Styles */
@media print {
    .sidebar,
    .search-container,
    .back-to-top,
    .theme-toggle {
        display: none !important;
    }
    
    .content {
        margin-left: 0;
    }
    
    .site-header {
        position: relative;
    }
}