/* 机械工程科普 - 专业主题样式 */

/* 基础样式和变量 */
:root {
    /* 机械工程主题颜色 */
    --primary-color: #2563eb;
    --primary-light: #dbeafe;
    --primary-dark: #1d4ed8;
    --secondary-color: #0ea5e9;
    --secondary-light: #e0f2fe;
    --accent-color: #8b5cf6;
    --accent-light: #ede9fe;
    --mechanical-red: #dc2626;
    --engineering-gray: #475569;
    --material-steel: #64748b;
    --material-aluminum: #94a3b8;
    
    /* 背景色 */
    --bg-color: #ffffff;
    --bg-light: #f8fafc;
    --bg-lighter: #f1f5f9;
    
    /* 文本色 */
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --text-light: #cbd5e1;
    
    /* 边框色 */
    --border-color: #e2e8f0;
    --border-light: #f1f5f9;
    
    /* 状态色 */
    --success-color: #10b981;
    --success-light: #d1fae5;
    --warning-color: #f59e0b;
    --warning-light: #fef3c7;
    --error-color: #ef4444;
    --error-light: #fee2e2;
    
    /* 阴影 */
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    
    /* 圆角 */
    --radius: 12px;
    --radius-sm: 8px;
    --radius-lg: 16px;
    
    /* 过渡 */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', 'Roboto', sans-serif;
    background-color: var(--bg-light);
    color: var(--text-primary);
    line-height: 1.6;
    font-size: 16px;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 流体力学背景动画 */
.hero {
    position: relative;
    overflow: hidden;
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(37, 99, 235, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(14, 165, 233, 0.15) 0%, transparent 50%);
    animation: fluidFlow 20s infinite linear;
    z-index: 0;
}

@keyframes fluidFlow {
    0% {
        background-position: 0 0, 0 0;
    }
    50% {
        background-position: 100px 100px, -100px -100px;
    }
    100% {
        background-position: 200px 200px, -200px -200px;
    }
}

/* 有限元网格动画 */
.fem-grid {
    position: absolute;
    width: 100%;
    height: 100%;
    background-image: 
        linear-gradient(rgba(37, 99, 235, 0.1) 1px, transparent 1px),
        linear-gradient(90deg, rgba(37, 99, 235, 0.1) 1px, transparent 1px);
    background-size: 30px 30px;
    opacity: 0.3;
    animation: gridMove 30s linear infinite;
    pointer-events: none;
}

@keyframes gridMove {
    0% {
        background-position: 0 0;
    }
    100% {
        background-position: 30px 30px;
    }
}

/* 机械动画 */
.engineering-animation {
    position: relative;
    width: 100%;
    height: 400px;
}

.gear-large, .gear-medium {
    position: absolute;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 0 30px rgba(37, 99, 235, 0.3);
}

.gear-large {
    width: 150px;
    height: 150px;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation: rotateClockwise 10s linear infinite;
}

.gear-medium {
    width: 100px;
    height: 100px;
    top: 30%;
    left: 30%;
    animation: rotateCounterClockwise 8s linear infinite;
}

.gear-teeth {
    position: absolute;
    width: 20px;
    height: 40px;
    background: white;
    border-radius: 4px;
}

.gear-large .gear-teeth:nth-child(1) { transform: rotate(0deg) translateX(75px); }
.gear-large .gear-teeth:nth-child(2) { transform: rotate(60deg) translateX(75px); }
.gear-large .gear-teeth:nth-child(3) { transform: rotate(120deg) translateX(75px); }
.gear-large .gear-teeth:nth-child(4) { transform: rotate(180deg) translateX(75px); }
.gear-large .gear-teeth:nth-child(5) { transform: rotate(240deg) translateX(75px); }
.gear-large .gear-teeth:nth-child(6) { transform: rotate(300deg) translateX(75px); }

.gear-medium .gear-teeth:nth-child(1) { transform: rotate(0deg) translateX(50px); }
.gear-medium .gear-teeth:nth-child(2) { transform: rotate(60deg) translateX(50px); }
.gear-medium .gear-teeth:nth-child(3) { transform: rotate(120deg) translateX(50px); }
.gear-medium .gear-teeth:nth-child(4) { transform: rotate(180deg) translateX(50px); }
.gear-medium .gear-teeth:nth-child(5) { transform: rotate(240deg) translateX(50px); }
.gear-medium .gear-teeth:nth-child(6) { transform: rotate(300deg) translateX(50px); }

@keyframes rotateClockwise {
    from { transform: translate(-50%, -50%) rotate(0deg); }
    to { transform: translate(-50%, -50%) rotate(360deg); }
}

@keyframes rotateCounterClockwise {
    from { transform: rotate(0deg); }
    to { transform: rotate(-360deg); }
}

.flow-arrows {
    position: absolute;
    width: 100%;
    height: 100%;
}

.arrow {
    position: absolute;
    width: 80px;
    height: 2px;
    background: var(--secondary-color);
}

.arrow::after {
    content: '';
    position: absolute;
    right: 0;
    top: -4px;
    width: 0;
    height: 0;
    border-left: 10px solid var(--secondary-color);
    border-top: 5px solid transparent;
    border-bottom: 5px solid transparent;
}

.arrow:nth-child(1) {
    top: 40%;
    left: 10%;
    animation: flowRight 8s linear infinite;
}

.arrow:nth-child(2) {
    top: 60%;
    left: 20%;
    animation: flowRight 10s linear infinite 1s;
}

.arrow:nth-child(3) {
    top: 80%;
    left: 15%;
    animation: flowRight 12s linear infinite 2s;
}

@keyframes flowRight {
    0% {
        transform: translateX(-100px);
        opacity: 0;
    }
    10% {
        opacity: 1;
    }
    90% {
        opacity: 1;
    }
    100% {
        transform: translateX(400px);
        opacity: 0;
    }
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 12px 28px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-family: 'Inter', sans-serif;
    text-decoration: none;
    font-size: 15px;
    outline: none;
}

.btn.primary {
    background-color: var(--primary-color);
    color: white;
    box-shadow: 0 4px 6px rgba(37, 99, 235, 0.2);
}

.btn.primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(37, 99, 235, 0.3);
}

.btn.primary:active {
    transform: translateY(0);
}

.btn.secondary {
    background-color: var(--secondary-color);
    color: white;
    box-shadow: 0 4px 6px rgba(14, 165, 233, 0.2);
}

.btn.secondary:hover {
    background-color: #0284c7;
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(14, 165, 233, 0.3);
}

.btn.outline {
    background-color: transparent;
    border: 2px solid var(--border-color);
    color: var(--text-primary);
}

.btn.outline:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background-color: var(--primary-light);
    transform: translateY(-2px);
}

.btn.liked {
    background-color: var(--error-light);
    border-color: var(--error-color);
    color: var(--error-color);
}

/* 导航栏 */
.navbar {
    background-color: var(--bg-color);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 18px 0;
    box-shadow: 0 1px 10px rgba(0, 0, 0, 0.05);
    backdrop-filter: blur(10px);
    background-color: rgba(255, 255, 255, 0.95);
}

.navbar .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 24px;
    font-weight: 700;
    color: var(--text-primary);
}

.nav-brand i {
    color: var(--primary-color);
    font-size: 28px;
}

.nav-links {
    display: flex;
    gap: 30px;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
    padding: 8px 0;
    font-size: 15px;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary-color);
}

.nav-links a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--primary-color);
    border-radius: 2px;
}

.admin-btn {
    background-color: var(--primary-color);
    color: white !important;
    padding: 8px 20px;
    border-radius: var(--radius-sm);
    font-weight: 600;
}

.admin-btn:hover {
    background-color: var(--primary-dark) !important;
    transform: translateY(-2px);
}

.nav-search {
    display: flex;
    align-items: center;
    background-color: var(--bg-light);
    border-radius: var(--radius-sm);
    overflow: hidden;
    border: 2px solid var(--border-color);
    transition: var(--transition);
}

.nav-search:focus-within {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.1);
}

.nav-search input {
    background: transparent;
    border: none;
    padding: 12px 16px;
    color: var(--text-primary);
    width: 240px;
    font-size: 14px;
}

.nav-search input:focus {
    outline: none;
}

.nav-search input::placeholder {
    color: var(--text-muted);
}

.nav-search button {
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 12px 16px;
    cursor: pointer;
    transition: var(--transition);
    font-size: 16px;
}

.nav-search button:hover {
    color: var(--primary-color);
    background-color: var(--primary-light);
}

.nav-toggle {
    display: none;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 24px;
    cursor: pointer;
    width: 40px;
    height: 40px;
    border-radius: 8px;
    transition: var(--transition);
}

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

/* 英雄区域 */
.hero {
    padding: 100px 0;
}

.hero .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 60px;
    position: relative;
    z-index: 1;
}

.hero-content {
    flex: 1;
    max-width: 600px;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 24px;
    color: var(--text-primary);
}

.highlight {
    color: var(--primary-color);
    position: relative;
    display: inline-block;
}

.highlight::after {
    content: '';
    position: absolute;
    bottom: 8px;
    left: 0;
    width: 100%;
    height: 8px;
    background-color: var(--primary-light);
    z-index: -1;
    border-radius: 4px;
}

.hero-subtitle {
    font-size: 20px;
    color: var(--text-secondary);
    margin-bottom: 36px;
    max-width: 500px;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.hero-stats {
    display: flex;
    gap: 30px;
    padding-top: 30px;
    border-top: 1px solid rgba(226, 232, 240, 0.5);
}

.hero-stats .stat {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--text-secondary);
    font-size: 15px;
}

.hero-stats .stat i {
    color: var(--primary-color);
    font-size: 18px;
}

.hero-stats .stat span {
    font-weight: 700;
    color: var(--text-primary);
    font-size: 18px;
}

.hero-visual {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 400px;
}

/* 计算器区域 */
.calculator-section {
    padding: 80px 0;
    background: linear-gradient(to bottom, var(--bg-light), white);
}

.calculator-section h2 {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
    text-align: center;
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 40px;
    font-size: 18px;
}

.calculator-tabs {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.calc-tab {
    padding: 12px 24px;
    background: white;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
    font-size: 14px;
}

.calc-tab:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background: var(--primary-light);
}

.calc-tab.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.calculator-content {
    max-width: 800px;
    margin: 0 auto;
}

.calc-panel {
    display: none;
    background: white;
    border-radius: var(--radius);
    padding: 30px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
}

.calc-panel.active {
    display: block;
    animation: fadeIn 0.5s ease;
}

.calc-panel h3 {
    font-size: 24px;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.calc-panel .formula {
    font-family: 'Courier New', monospace;
    font-size: 20px;
    background: var(--bg-light);
    padding: 15px;
    border-radius: var(--radius-sm);
    text-align: center;
    margin-bottom: 30px;
    color: var(--mechanical-red);
    font-weight: 600;
}

.input-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 30px;
}

.input-field {
    display: flex;
    flex-direction: column;
}

.input-field label {
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 14px;
}

.input-field input {
    padding: 14px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 16px;
    transition: var(--transition);
}

.input-field input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.result-box {
    background: var(--bg-light);
    border-radius: var(--radius-sm);
    padding: 20px;
    margin-top: 30px;
    border: 2px dashed var(--border-color);
}

.result-box h4 {
    margin-bottom: 10px;
    color: var(--text-primary);
}

.result-box p {
    font-size: 18px;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.result-note {
    font-size: 14px !important;
    color: var(--text-muted) !important;
    margin-top: 10px;
}

.material-reference {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.material-reference h4 {
    margin-bottom: 15px;
    color: var(--text-primary);
}

.material-reference ul {
    list-style: none;
    padding: 0;
}

.material-reference li {
    padding: 8px 0;
    border-bottom: 1px solid var(--border-light);
    color: var(--text-secondary);
}

.material-reference li:last-child {
    border-bottom: none;
}

/* 文章区域 */
.articles-section {
    padding: 80px 0;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 50px;
    flex-wrap: wrap;
    gap: 20px;
}

.section-header h2 {
    font-size: 36px;
    font-weight: 700;
    color: var(--text-primary);
}

.category-filter select {
    background-color: white;
    color: var(--text-primary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 12px 20px;
    min-width: 200px;
    font-size: 14px;
    transition: var(--transition);
    font-weight: 500;
    cursor: pointer;
}

.category-filter select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
}

.article-card {
    background-color: white;
    border-radius: var(--radius);
    overflow: hidden;
    transition: var(--transition);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.article-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-color);
}

.article-card-header {
    padding: 25px 25px 0;
    flex: 1;
}

.article-card-category {
    display: inline-block;
    background-color: var(--primary-light);
    color: var(--primary-color);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    margin-bottom: 15px;
    border: 1px solid rgba(37, 99, 235, 0.2);
}

.article-card-title {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 12px;
    line-height: 1.4;
    color: var(--text-primary);
}

.article-card-excerpt {
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.5;
    font-size: 14px;
}

.article-card-footer {
    padding: 20px 25px 25px;
    border-top: 1px solid var(--border-light);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--bg-light);
}

.article-card-meta {
    display: flex;
    gap: 15px;
    color: var(--text-muted);
    font-size: 13px;
}

.article-card-meta span {
    display: flex;
    align-items: center;
    gap: 5px;
}

.load-more {
    display: flex;
    justify-content: center;
}

/* 分类区域 */
.categories-section {
    padding: 80px 0;
    background-color: var(--bg-light);
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 25px;
    margin-top: 40px;
}

.category-card {
    background-color: white;
    border-radius: var(--radius);
    padding: 30px;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    cursor: pointer;
    box-shadow: var(--shadow);
    position: relative;
    overflow: hidden;
}

.category-card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-lg);
    transform: translateY(-5px);
}

.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
}

.category-icon {
    width: 60px;
    height: 60px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
}

.category-icon i {
    font-size: 28px;
    color: var(--primary-color);
}

.category-card h3 {
    margin-bottom: 10px;
    font-size: 20px;
    color: var(--text-primary);
    font-weight: 700;
}

.category-card p {
    color: var(--text-secondary);
    margin-bottom: 15px;
    font-size: 14px;
    line-height: 1.5;
}

.category-count {
    display: inline-block;
    background: var(--bg-light);
    color: var(--text-secondary);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
    border: 1px solid var(--border-color);
}

/* 学习路径 */
.learning-paths-section {
    padding: 80px 0;
}

.paths-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(500px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.path-card {
    background: white;
    border-radius: var(--radius);
    padding: 30px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.path-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-3px);
}

.path-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-light);
}

.path-header h3 {
    font-size: 22px;
    color: var(--text-primary);
    font-weight: 700;
}

.path-level {
    background: var(--secondary-light);
    color: var(--secondary-color);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    border: 1px solid rgba(14, 165, 233, 0.3);
}

.path-steps {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.step {
    display: flex;
    gap: 15px;
    align-items: flex-start;
}

.step-number {
    width: 36px;
    height: 36px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 16px;
    flex-shrink: 0;
}

.step-content {
    flex: 1;
}

.step-content h4 {
    font-size: 16px;
    color: var(--text-primary);
    margin-bottom: 5px;
    font-weight: 600;
}

.step-content p {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 5px;
}

.step-time {
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 500;
}

.start-path {
    margin-top: 25px;
    width: 100%;
}

/* 工具区域 */
.tools-section {
    padding: 80px 0;
    background-color: var(--bg-light);
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 25px;
    margin-top: 40px;
}

.tool-card {
    background: white;
    border-radius: var(--radius);
    padding: 30px;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    box-shadow: var(--shadow);
}

.tool-card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-lg);
    transform: translateY(-5px);
}

.tool-icon {
    width: 60px;
    height: 60px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
}

.tool-icon i {
    font-size: 28px;
    color: var(--primary-color);
}

.tool-card h3 {
    margin-bottom: 10px;
    color: var(--text-primary);
    font-size: 18px;
    font-weight: 700;
}

.tool-card p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-size: 14px;
    line-height: 1.5;
}

/* 关于区域 */
.about-section {
    padding: 80px 0;
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-content h2 {
    font-size: 36px;
    margin-bottom: 25px;
    color: var(--text-primary);
    text-align: center;
}

.about-content p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-size: 18px;
    line-height: 1.8;
    text-align: center;
}

.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 25px;
    margin: 40px 0;
}

.team-member {
    background: white;
    border-radius: var(--radius);
    padding: 25px;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.team-member:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.member-avatar {
    width: 80px;
    height: 80px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 15px;
}

.member-avatar i {
    font-size: 36px;
    color: var(--primary-color);
}

.team-member h4 {
    margin-bottom: 5px;
    color: var(--text-primary);
    font-size: 18px;
}

.member-title {
    color: var(--primary-color);
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 10px;
}

.member-bio {
    color: var(--text-secondary);
    font-size: 13px;
    line-height: 1.5;
}

.about-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-top: 40px;
}

/* 文章详情页样式 */
.article-main {
    padding: 50px 0 80px;
}

.article-container {
    background-color: white;
    border-radius: var(--radius);
    padding: 40px;
    border: 1px solid var(--border-color);
    margin-bottom: 40px;
    box-shadow: var(--shadow-lg);
}

.article-header {
    margin-bottom: 40px;
    padding-bottom: 25px;
    border-bottom: 1px solid var(--border-light);
}

.article-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 20px;
}

.article-category, .article-difficulty {
    display: inline-block;
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
}

.article-category {
    background-color: var(--primary-light);
    color: var(--primary-color);
    border: 1px solid rgba(37, 99, 235, 0.3);
}

.article-difficulty {
    background-color: var(--warning-light);
    color: var(--warning-color);
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.article-title {
    font-size: 40px;
    font-weight: 800;
    line-height: 1.3;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.article-author {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    flex-wrap: wrap;
    gap: 20px;
}

.author-info {
    display: flex;
    align-items: center;
    gap: 12px;
}

.author-info i {
    font-size: 24px;
    color: var(--primary-color);
}

.author-info strong {
    color: var(--text-primary);
    font-size: 16px;
}

.author-info span {
    color: var(--text-secondary);
    font-size: 13px;
}

.article-stats {
    display: flex;
    gap: 20px;
    color: var(--text-muted);
    font-size: 14px;
}

.article-stats span {
    display: flex;
    align-items: center;
    gap: 6px;
}

.article-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 20px;
}

.tag {
    background-color: var(--bg-light);
    color: var(--text-secondary);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 13px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    font-weight: 500;
}

.tag:hover {
    background-color: var(--primary-light);
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.article-body {
    font-size: 18px;
    line-height: 1.8;
    color: var(--text-primary);
}

.article-body h1,
.article-body h2,
.article-body h3,
.article-body h4 {
    margin: 30px 0 15px;
    color: var(--text-primary);
    line-height: 1.4;
}

.article-body h1 {
    font-size: 32px;
    font-weight: 800;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border-light);
}

.article-body h2 {
    font-size: 28px;
    font-weight: 700;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border-light);
}

.article-body h3 {
    font-size: 24px;
    font-weight: 600;
}

.article-body h4 {
    font-size: 20px;
    font-weight: 600;
}

.article-body p {
    margin-bottom: 24px;
}

.article-body ul,
.article-body ol {
    margin-bottom: 24px;
    padding-left: 30px;
}

.article-body li {
    margin-bottom: 10px;
}

.article-body code {
    background-color: var(--bg-light);
    padding: 2px 8px;
    border-radius: 6px;
    font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
    font-size: 15px;
    color: var(--mechanical-red);
    border: 1px solid var(--border-color);
}

.article-body pre {
    background-color: #1a202c;
    padding: 20px;
    border-radius: 10px;
    overflow-x: auto;
    margin: 24px 0;
}

.article-body pre code {
    background: transparent;
    border: none;
    color: #e2e8f0;
    padding: 0;
    font-size: 14px;
}

.article-body blockquote {
    border-left: 4px solid var(--primary-color);
    padding-left: 20px;
    margin: 24px 0;
    color: var(--text-secondary);
    font-style: italic;
    background-color: var(--bg-light);
    padding: 20px;
    border-radius: 0 10px 10px 0;
}

.article-body img {
    max-width: 100%;
    border-radius: var(--radius);
    margin: 24px 0;
    box-shadow: var(--shadow);
}

.article-body table {
    width: 100%;
    border-collapse: collapse;
    margin: 24px 0;
    box-shadow: var(--shadow);
    border-radius: 8px;
    overflow: hidden;
}

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

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

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

/* 交互式公式 */
.interactive-formula {
    background: var(--bg-light);
    border-radius: var(--radius);
    padding: 25px;
    margin: 40px 0;
    border: 2px solid var(--border-color);
}

.interactive-formula h3 {
    margin-bottom: 20px;
    color: var(--text-primary);
    font-size: 20px;
}

.formula-display {
    background: white;
    padding: 20px;
    border-radius: var(--radius-sm);
    text-align: center;
    margin-bottom: 20px;
    border: 1px solid var(--border-color);
}

.formula-display p {
    font-family: 'Courier New', monospace;
    font-size: 22px;
    color: var(--mechanical-red);
    font-weight: 600;
}

.formula-inputs {
    display: grid;
    grid-template-columns: 1fr 1fr auto;
    gap: 15px;
    margin-bottom: 20px;
    align-items: end;
}

.formula-result {
    background: white;
    padding: 15px;
    border-radius: var(--radius-sm);
    font-size: 18px;
    font-weight: 600;
    color: var(--primary-color);
    text-align: center;
    border: 2px dashed var(--border-color);
}

/* 知识要点 */
.key-points {
    background: linear-gradient(135deg, var(--primary-light), var(--secondary-light));
    border-radius: var(--radius);
    padding: 25px;
    margin: 40px 0;
    border: 1px solid rgba(37, 99, 235, 0.3);
}

.key-points h3 {
    margin-bottom: 20px;
    color: var(--text-primary);
    font-size: 20px;
}

.key-points ul {
    list-style: none;
    padding: 0;
}

.key-points li {
    padding: 12px 0 12px 30px;
    position: relative;
    color: var(--text-primary);
    font-size: 16px;
    border-bottom: 1px solid rgba(37, 99, 235, 0.1);
}

.key-points li:last-child {
    border-bottom: none;
}

.key-points li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: bold;
}

/* 相关资源 */
.related-resources {
    margin: 40px 0;
}

.related-resources h3 {
    margin-bottom: 25px;
    color: var(--text-primary);
    font-size: 24px;
}

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
}

.resource-card {
    background: white;
    border-radius: var(--radius);
    padding: 25px;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    box-shadow: var(--shadow);
}

.resource-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.resource-card i {
    font-size: 36px;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.resource-card h4 {
    margin-bottom: 10px;
    color: var(--text-primary);
    font-size: 18px;
}

.resource-card p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-size: 14px;
}

/* 文章互动 */
.article-interaction {
    background: var(--bg-light);
    border-radius: var(--radius);
    padding: 25px;
    margin-top: 40px;
    border: 1px solid var(--border-color);
}

.interaction-stats {
    display: flex;
    justify-content: space-around;
    margin-bottom: 25px;
    flex-wrap: wrap;
    gap: 20px;
}

.interaction-stats .stat {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--text-secondary);
    font-size: 15px;
}

.interaction-stats .stat i {
    color: var(--primary-color);
    font-size: 18px;
}

.interaction-stats .stat span {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 16px;
}

.interaction-actions {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

/* 相关文章 */
.related-articles {
    margin-top: 50px;
}

.related-articles h3 {
    font-size: 28px;
    margin-bottom: 30px;
    color: var(--text-primary);
    font-weight: 700;
}

.related-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 25px;
}

.related-card {
    background-color: white;
    border-radius: var(--radius);
    padding: 25px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    cursor: pointer;
    box-shadow: var(--shadow);
}

.related-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.related-card-category {
    display: inline-block;
    background-color: var(--primary-light);
    color: var(--primary-color);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    margin-bottom: 15px;
}

.related-card-title {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
    line-height: 1.4;
}

.related-card-excerpt {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 15px;
    line-height: 1.5;
}

.related-card-meta {
    display: flex;
    justify-content: space-between;
    color: var(--text-muted);
    font-size: 12px;
}

/* 学习建议 */
.study-suggestions {
    background: linear-gradient(135deg, var(--bg-light), white);
    border-radius: var(--radius);
    padding: 30px;
    margin-top: 40px;
    border: 1px solid var(--border-color);
}

.study-suggestions h3 {
    margin-bottom: 25px;
    color: var(--text-primary);
    font-size: 24px;
}

.suggestions-content {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.suggestion {
    display: flex;
    align-items: flex-start;
    gap: 15px;
    padding: 20px;
    background: white;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.suggestion:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow);
}

.suggestion i {
    font-size: 24px;
    color: var(--primary-color);
    margin-top: 5px;
}

.suggestion h4 {
    margin-bottom: 8px;
    color: var(--text-primary);
    font-size: 16px;
    font-weight: 600;
}

.suggestion p {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.5;
}

/* 页脚 */
.footer {
    background-color: var(--bg-color);
    border-top: 1px solid var(--border-color);
    padding: 60px 0 30px;
    box-shadow: 0 -1px 10px rgba(0, 0, 0, 0.05);
}

.footer-content {
    max-width: 1000px;
    margin: 0 auto;
}

.footer-brand {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.footer-brand i {
    color: var(--primary-color);
    font-size: 32px;
}

.footer-tagline {
    color: var(--text-secondary);
    margin-bottom: 30px;
    font-size: 18px;
    text-align: center;
    font-weight: 500;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    margin-bottom: 40px;
}

.footer-column h4 {
    margin-bottom: 20px;
    color: var(--text-primary);
    font-size: 16px;
    font-weight: 600;
}

.footer-column a {
    display: block;
    color: var(--text-secondary);
    text-decoration: none;
    margin-bottom: 12px;
    font-size: 14px;
    transition: var(--transition);
}

.footer-column a:hover {
    color: var(--primary-color);
    transform: translateX(5px);
}

.footer-social {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 40px;
}

.footer-social a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    background-color: var(--bg-light);
    border-radius: 50%;
    color: var(--text-primary);
    font-size: 20px;
    transition: var(--transition);
    text-decoration: none;
}

.footer-social a:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(37, 99, 235, 0.3);
}

.footer-copyright {
    color: var(--text-muted);
    font-size: 14px;
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

/* 模态框 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    z-index: 2000;
    align-items: center;
    justify-content: center;
    padding: 20px;
    backdrop-filter: blur(5px);
}

.modal.active {
    display: flex;
    animation: modalFadeIn 0.3s ease;
}

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

.modal-content {
    background-color: var(--bg-color);
    border-radius: var(--radius);
    width: 100%;
    max-width: 700px;
    max-height: 85vh;
    overflow: hidden;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-xl);
    animation: modalSlideUp 0.4s ease;
}

@keyframes modalSlideUp {
    from { transform: translateY(30px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 25px 30px;
    border-bottom: 1px solid var(--border-light);
    background-color: var(--bg-light);
}

.modal-header h3 {
    margin: 0;
    color: var(--text-primary);
    font-size: 22px;
    font-weight: 700;
}

.modal-close {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 28px;
    cursor: pointer;
    line-height: 1;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    transition: var(--transition);
}

.modal-close:hover {
    background-color: var(--bg-lighter);
    color: var(--text-primary);
}

.modal-body {
    padding: 30px;
    overflow-y: auto;
    max-height: calc(85vh - 83px);
}

.search-box {
    display: flex;
    margin-bottom: 25px;
    position: relative;
}

.search-box input {
    flex: 1;
    background-color: var(--bg-light);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 16px 20px;
    color: var(--text-primary);
    font-size: 16px;
    transition: var(--transition);
}

.search-box input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.1);
}

.search-box button {
    background-color: var(--primary-color);
    border: none;
    color: white;
    padding: 0 25px;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    cursor: pointer;
    transition: var(--transition);
    font-size: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.search-results {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.search-result-item {
    padding: 20px;
    background-color: var(--bg-light);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    cursor: pointer;
}

.search-result-item:hover {
    border-color: var(--primary-color);
    background-color: var(--primary-light);
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.search-result-title {
    font-size: 17px;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.search-result-excerpt {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 12px;
    line-height: 1.5;
}

.search-result-meta {
    display: flex;
    justify-content: space-between;
    color: var(--text-muted);
    font-size: 13px;
}

.no-results {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-muted);
    font-size: 16px;
}

/* 工程公式库样式 */
.formulas-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
    margin-top: 25px;
}

.formula-card {
    background: white;
    border-radius: var(--radius-sm);
    padding: 20px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    box-shadow: var(--shadow);
}

.formula-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.formula-card h4 {
    margin-bottom: 10px;
    color: var(--text-primary);
    font-size: 16px;
    font-weight: 600;
}

.formula-card .formula {
    font-family: 'Courier New', monospace;
    font-size: 18px;
    color: var(--mechanical-red);
    font-weight: 600;
    margin-bottom: 10px;
    padding: 10px;
    background: var(--bg-light);
    border-radius: 6px;
    text-align: center;
}

.formula-card p {
    color: var(--text-secondary);
    font-size: 13px;
    line-height: 1.5;
}

.materials-table {
    overflow-x: auto;
    margin-top: 20px;
}

.materials-table table {
    width: 100%;
    border-collapse: collapse;
    box-shadow: var(--shadow);
    border-radius: 8px;
    overflow: hidden;
}

.materials-table th,
.materials-table td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.materials-table th {
    background-color: var(--bg-light);
    font-weight: 600;
    color: var(--text-primary);
    font-size: 14px;
}

.materials-table td {
    color: var(--text-secondary);
    font-size: 14px;
}

.materials-table tr:hover {
    background-color: var(--bg-light);
}

/* 加载动画 */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 60px 40px;
    color: var(--text-secondary);
    grid-column: 1 / -1;
    background: white;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
}

.spinner {
    width: 50px;
    height: 50px;
    border: 3px solid var(--border-light);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 20px;
}

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

/* 错误消息 */
.error-message {
    text-align: center;
    padding: 60px 40px;
    background: white;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

.error-message h2 {
    margin-bottom: 20px;
    color: var(--error-color);
    font-size: 28px;
}

.error-message p {
    color: var(--text-secondary);
    margin-bottom: 30px;
    font-size: 18px;
}

/* 响应式设计 */
@media (max-width: 1200px) {
    .hero .container {
        gap: 40px;
    }
    
    .hero-title {
        font-size: 48px;
    }
    
    .paths-container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 992px) {
    .hero .container {
        flex-direction: column;
        text-align: center;
        gap: 50px;
    }
    
    .hero-visual {
        order: -1;
    }
    
    .engineering-animation {
        height: 300px;
    }
    
    .hero-title {
        font-size: 42px;
    }
    
    .hero-subtitle {
        font-size: 18px;
        margin: 0 auto 30px;
    }
    
    .hero-buttons {
        justify-content: center;
    }
    
    .hero-stats {
        justify-content: center;
    }
    
    .input-group {
        grid-template-columns: 1fr;
    }
    
    .formula-inputs {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: var(--bg-color);
        flex-direction: column;
        padding: 20px;
        box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
        border-top: 1px solid var(--border-color);
        z-index: 999;
        border-radius: 0 0 var(--radius) var(--radius);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .nav-links a.active::after {
        display: none;
    }
    
    .nav-links a {
        padding: 12px 0;
        border-bottom: 1px solid var(--border-light);
    }
    
    .nav-links a:last-child {
        border-bottom: none;
    }
    
    .nav-search {
        display: none;
    }
    
    .nav-toggle {
        display: block;
    }
    
    .articles-grid {
        grid-template-columns: 1fr;
    }
    
    .categories-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .article-container {
        padding: 25px;
    }
    
    .article-title {
        font-size: 32px;
    }
    
    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 20px;
    }
    
    .category-filter select {
        width: 100%;
    }
    
    .about-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .about-buttons .btn {
        width: 100%;
        max-width: 300px;
    }
    
    .article-actions {
        flex-direction: column;
    }
    
    .article-actions .btn {
        width: 100%;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .footer-social {
        gap: 15px;
    }
    
    .footer-social a {
        width: 45px;
        height: 45px;
    }
    
    .paths-container {
        grid-template-columns: 1fr;
    }
    
    .tools-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .team-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .related-grid {
        grid-template-columns: 1fr;
    }
    
    .suggestions-content {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        max-height: 90vh;
    }
    
    .modal-body {
        max-height: calc(90vh - 83px);
    }
}

@media (max-width: 576px) {
    .categories-grid {
        grid-template-columns: 1fr;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .hero-buttons {
        flex-direction: column;
        width: 100%;
    }
    
    .hero-buttons .btn {
        width: 100%;
    }
    
    .article-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .article-author {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .article-stats {
        width: 100%;
        justify-content: space-between;
    }
    
    .related-grid {
        grid-template-columns: 1fr;
    }
    
    .tools-grid {
        grid-template-columns: 1fr;
    }
    
    .team-grid {
        grid-template-columns: 1fr;
    }
    
    .interaction-stats {
        flex-direction: column;
        align-items: center;
        gap: 15px;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: 20px;
        align-items: center;
    }
    
    .calculator-tabs {
        flex-direction: column;
    }
    
    .calc-tab {
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 36px;
    }
    
    .hero-subtitle {
        font-size: 16px;
    }
    
    .section-header h2 {
        font-size: 28px;
    }
    
    .article-title {
        font-size: 28px;
    }
    
    .article-body {
        font-size: 16px;
    }
    
    .resources-grid {
        grid-template-columns: 1fr;
    }
    
    .formulas-grid {
        grid-template-columns: 1fr;
    }
}

/* 打印样式 */
@media print {
    .navbar,
    .hero,
    .footer,
    .interaction-actions,
    .calculator-section,
    .learning-paths-section,
    .tools-section,
    .about-section {
        display: none !important;
    }
    
    body {
        background: white !important;
        color: black !important;
    }
    
    .article-container {
        box-shadow: none !important;
        border: none !important;
        padding: 0 !important;
    }
    
    .article-title {
        font-size: 24pt !important;
        color: black !important;
    }
    
    .article-body {
        font-size: 12pt !important;
        color: black !important;
    }
    
    a {
        color: black !important;
        text-decoration: underline !important;
    }
}