/* ============================================
   妊娠呕吐科普网页 - 苹果风格CSS
   ============================================ */

/* CSS变量定义 */
:root {
    /* 苹果风格配色 */
    --color-primary: #007AFF;
    --color-secondary: #5856D6;
    --color-gradient-start: #007AFF;
    --color-gradient-end: #5856D6;
    
    /* 中性色 */
    --color-white: #FFFFFF;
    --color-black: #000000;
    --color-gray-50: #F5F5F7;
    --color-gray-100: #E8E8ED;
    --color-gray-200: #D2D2D7;
    --color-gray-400: #86868B;
    --color-gray-600: #424245;
    --color-gray-800: #1D1D1F;
    
    /* 功能色 */
    --color-success: #34C759;
    --color-warning: #FF9500;
    --color-danger: #FF3B30;
    
    /* 字体 */
    --font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    
    /* 间距 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;
    
    /* 圆角 */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 18px;
    --radius-xl: 28px;
    --radius-full: 9999px;
    
    /* 阴影 */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.16);
    
    /* 过渡 */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* 容器宽度 */
    --container-max: 1200px;
    --container-narrow: 980px;
}

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

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

body {
    font-family: var(--font-family);
    font-weight: 400;
    line-height: 1.6;
    color: var(--color-gray-800);
    background-color: var(--color-white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

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

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition-fast);
}

ul {
    list-style: none;
}

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

/* 容器 */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* ============================================
   导航栏
   ============================================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.72);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    transition: var(--transition-normal);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.92);
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 52px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--color-gray-800);
}

.logo-icon {
    font-size: 1.3rem;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.nav-link {
    font-size: 0.875rem;
    font-weight: 400;
    color: var(--color-gray-600);
    padding: 0.5rem 0;
    position: relative;
    transition: var(--transition-fast);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--color-gradient-start), var(--color-gradient-end));
    transition: var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-gray-800);
}

.nav-link:hover::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 5px;
}

.nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--color-gray-800);
    border-radius: 1px;
    transition: var(--transition-fast);
}

/* ============================================
   Hero区域
   ============================================ */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 120px var(--spacing-lg) 80px;
    overflow: hidden;
    background: linear-gradient(180deg, #FAFAFA 0%, #FFFFFF 100%);
}

.hero-background {
    position: absolute;
    inset: 0;
    overflow: hidden;
    pointer-events: none;
}

.gradient-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.5;
    animation: float 8s ease-in-out infinite;
}

.orb-1 {
    width: 500px;
    height: 500px;
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.3), rgba(88, 86, 214, 0.2));
    top: -100px;
    right: -100px;
    animation-delay: 0s;
}

.orb-2 {
    width: 400px;
    height: 400px;
    background: linear-gradient(135deg, rgba(88, 86, 214, 0.25), rgba(0, 122, 255, 0.15));
    bottom: -50px;
    left: -100px;
    animation-delay: -3s;
}

.orb-3 {
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.2), rgba(88, 86, 214, 0.3));
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation-delay: -5s;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
    }
    33% {
        transform: translate(30px, -30px) scale(1.05);
    }
    66% {
        transform: translate(-20px, 20px) scale(0.95);
    }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 0.5rem 1rem;
    background: rgba(0, 122, 255, 0.08);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-primary);
    margin-bottom: var(--spacing-lg);
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.02em;
}

.title-line {
    display: block;
}

.gradient-text {
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(1rem, 2vw, 1.25rem);
    font-weight: 400;
    color: var(--color-gray-600);
    line-height: 1.7;
    margin-bottom: var(--spacing-xl);
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--color-gray-400);
}

.hero-cta {
    margin-bottom: var(--spacing-2xl);
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 1rem 2rem;
    border-radius: var(--radius-full);
    font-size: 1rem;
    font-weight: 500;
    transition: var(--transition-normal);
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    color: var(--color-white);
    box-shadow: 0 4px 16px rgba(0, 122, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0, 122, 255, 0.4);
}

.btn-icon {
    width: 18px;
    height: 18px;
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(4px);
    }
}

.hero-scroll {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
}

.scroll-indicator {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.75rem;
    color: var(--color-gray-400);
}

.scroll-arrow {
    width: 24px;
    height: 24px;
    border-right: 2px solid var(--color-gray-400);
    border-bottom: 2px solid var(--color-gray-400);
    transform: rotate(45deg);
    animation: scrollBounce 2s infinite;
}

@keyframes scrollBounce {
    0%, 100% {
        transform: rotate(45deg) translate(0, 0);
    }
    50% {
        transform: rotate(45deg) translate(4px, 4px);
    }
}

/* ============================================
   通用Section样式
   ============================================ */
.section {
    padding: var(--spacing-3xl) 0;
    position: relative;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--spacing-2xl);
}

.section-tag {
    display: inline-block;
    padding: 0.4rem 1rem;
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.08), rgba(88, 86, 214, 0.08));
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    color: var(--color-gray-800);
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.02em;
}

.section-desc {
    font-size: 1.125rem;
    color: var(--color-gray-400);
}

/* ============================================
   关于妊娠呕吐
   ============================================ */
.section-about {
    background: var(--color-white);
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-lg);
}

.about-card {
    background: var(--color-gray-50);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    transition: var(--transition-normal);
    border: 1px solid transparent;
}

.about-card:hover {
    background: var(--color-white);
    border-color: var(--color-gray-100);
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.card-icon {
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.1), rgba(88, 86, 214, 0.1));
    border-radius: var(--radius-lg);
    font-size: 1.75rem;
    margin-bottom: var(--spacing-md);
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-gray-800);
    margin-bottom: var(--spacing-sm);
}

.card-text {
    font-size: 0.95rem;
    color: var(--color-gray-600);
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
}

.card-tags {
    display: flex;
    gap: var(--spacing-xs);
    flex-wrap: wrap;
}

.tag {
    padding: 0.3rem 0.75rem;
    background: var(--color-gray-100);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--color-gray-600);
}

.tag-warning {
    background: rgba(255, 149, 0, 0.12);
    color: var(--color-warning);
}

.tag-danger {
    background: rgba(255, 59, 48, 0.12);
    color: var(--color-danger);
}

/* ============================================
   时间线
   ============================================ */
.section-timeline {
    background: linear-gradient(180deg, var(--color-gray-50) 0%, var(--color-white) 100%);
}

.timeline-chart {
    margin-bottom: var(--spacing-2xl);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.timeline-chart img {
    width: 100%;
    height: auto;
}

.timeline-content {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
}

.timeline-content::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: 100%;
    background: linear-gradient(180deg, var(--color-gradient-start), var(--color-gradient-end));
    opacity: 0.3;
}

.timeline-item {
    display: flex;
    align-items: flex-start;
    margin-bottom: var(--spacing-xl);
    position: relative;
}

.timeline-item:nth-child(odd) {
    flex-direction: row;
    padding-right: 50%;
}

.timeline-item:nth-child(even) {
    flex-direction: row-reverse;
    padding-left: 50%;
}

.timeline-marker {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1;
}

.year {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    border-radius: 50%;
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--color-white);
    box-shadow: var(--shadow-md);
}

.timeline-card {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-md);
    max-width: 320px;
    margin: 0 var(--spacing-lg);
}

.timeline-card h4 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--color-gray-800);
    margin-bottom: var(--spacing-xs);
}

.timeline-card p {
    font-size: 0.875rem;
    color: var(--color-gray-600);
    line-height: 1.6;
}

/* ============================================
   诊断技术
   ============================================ */
.section-diagnosis {
    background: var(--color-white);
}

.diagnosis-chart {
    margin-bottom: var(--spacing-2xl);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.diagnosis-chart img {
    width: 100%;
    height: auto;
}

.diagnosis-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.diagnosis-era {
    background: var(--color-gray-50);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    border: 2px solid transparent;
    transition: var(--transition-normal);
}

.diagnosis-era:hover {
    background: var(--color-white);
    border-color: var(--color-gray-100);
    box-shadow: var(--shadow-lg);
}

.diagnosis-era.featured {
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.05), rgba(88, 86, 214, 0.05));
    border-color: rgba(0, 122, 255, 0.2);
}

.era-header {
    margin-bottom: var(--spacing-md);
}

.era-period {
    display: inline-block;
    padding: 0.3rem 0.75rem;
    background: var(--color-white);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.era-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-gray-800);
}

.era-list {
    margin-bottom: var(--spacing-md);
}

.era-list li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    font-size: 0.9rem;
    color: var(--color-gray-600);
    border-bottom: 1px solid var(--color-gray-100);
}

.era-list li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-weight: bold;
}

.era-list li:last-child {
    border-bottom: none;
}

.era-limitation {
    padding: var(--spacing-sm);
    background: rgba(255, 59, 48, 0.05);
    border-radius: var(--radius-md);
}

.era-limitation .success {
    color: var(--color-success);
}

.limitation-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-danger);
    margin-bottom: 0.25rem;
}

.era-limitation p {
    font-size: 0.85rem;
    color: var(--color-gray-600);
}

/* ============================================
   治疗方法
   ============================================ */
.section-treatment {
    background: linear-gradient(180deg, var(--color-white) 0%, var(--color-gray-50) 100%);
}

.treatment-chart {
    margin-bottom: var(--spacing-2xl);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.treatment-chart img {
    width: 100%;
    height: auto;
}

.treatment-flow {
    max-width: 800px;
    margin: 0 auto;
}

.treatment-level {
    background: var(--color-white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    margin-bottom: var(--spacing-md);
}

.level-badge {
    display: inline-block;
    padding: 0.4rem 1rem;
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.level-1 {
    background: rgba(52, 199, 89, 0.12);
    color: var(--color-success);
}

.level-2 {
    background: rgba(0, 122, 255, 0.12);
    color: var(--color-primary);
}

.level-3 {
    background: rgba(255, 149, 0, 0.12);
    color: var(--color-warning);
}

.level-4 {
    background: rgba(255, 59, 48, 0.12);
    color: var(--color-danger);
}

.level-content h4 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-gray-800);
    margin-bottom: var(--spacing-md);
}

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

.level-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: var(--color-gray-50);
    border-radius: var(--radius-md);
}

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

.item-info {
    display: flex;
    flex-direction: column;
}

.item-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--color-gray-800);
}

.item-evidence {
    font-size: 0.75rem;
    color: var(--color-gray-400);
}

.treatment-arrow {
    text-align: center;
    font-size: 1.5rem;
    color: var(--color-gray-400);
    margin: var(--spacing-sm) 0;
}

/* ============================================
   数据洞察
   ============================================ */
.section-data {
    background: var(--color-white);
}

.data-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.data-card {
    background: var(--color-gray-50);
    border-radius: var(--radius-xl);
    overflow: hidden;
    transition: var(--transition-normal);
}

.data-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.data-chart {
    padding: var(--spacing-md);
}

.data-chart img {
    width: 100%;
    border-radius: var(--radius-md);
}

.data-info {
    padding: var(--spacing-md);
    padding-top: 0;
}

.data-info h4 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--color-gray-800);
    margin-bottom: 0.25rem;
}

.data-info p {
    font-size: 0.875rem;
    color: var(--color-gray-600);
}

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

.stat-card {
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.05), rgba(88, 86, 214, 0.05));
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    text-align: center;
    transition: var(--transition-normal);
}

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

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

.stat-value {
    display: block;
    font-size: 1.75rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.25rem;
}

.stat-card .stat-label {
    font-size: 0.875rem;
    color: var(--color-gray-600);
}

/* ============================================
   病理机制
   ============================================ */
.section-mechanism {
    background: linear-gradient(180deg, var(--color-gray-50) 0%, var(--color-white) 100%);
}

.mechanism-intro {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: center;
    margin-bottom: var(--spacing-2xl);
}

.intro-text h3 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-gray-800);
    margin-bottom: var(--spacing-md);
}

.intro-text p {
    font-size: 1rem;
    color: var(--color-gray-600);
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.key-finding {
    padding: var(--spacing-md);
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.08), rgba(88, 86, 214, 0.08));
    border-radius: var(--radius-lg);
    border-left: 4px solid var(--color-primary);
}

.finding-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.25rem;
}

.key-finding p {
    margin: 0;
    font-size: 0.95rem;
    color: var(--color-gray-800);
}

.intro-chart img {
    width: 100%;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
}

.mechanism-flow {
    background: var(--color-white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    margin-bottom: var(--spacing-2xl);
}

.flow-title {
    text-align: center;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-gray-800);
    margin-bottom: var(--spacing-lg);
}

.flow-steps {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.flow-step {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    max-width: 150px;
}

.step-number {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    border-radius: 50%;
    font-size: 1rem;
    font-weight: 700;
    color: var(--color-white);
    margin-bottom: var(--spacing-xs);
}

.step-name {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-gray-800);
    margin-bottom: 0.25rem;
}

.step-desc {
    font-size: 0.75rem;
    color: var(--color-gray-400);
}

.flow-arrow {
    font-size: 1.5rem;
    color: var(--color-primary);
    font-weight: bold;
}

.mechanism-charts {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-lg);
}

.chart-item {
    background: var(--color-white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-md);
    text-align: center;
}

.chart-item img {
    width: 100%;
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
}

.chart-caption {
    font-size: 0.875rem;
    color: var(--color-gray-600);
}

/* ============================================
   图表展示
   ============================================ */
.section-charts {
    background: var(--color-white);
}

.charts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-lg);
}

.chart-card {
    position: relative;
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
}

.chart-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.chart-card img {
    width: 100%;
    height: 280px;
    object-fit: cover;
}

.chart-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: var(--spacing-md);
    background: linear-gradient(180deg, transparent, rgba(0, 0, 0, 0.8));
    color: var(--color-white);
}

.chart-overlay h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.chart-overlay p {
    font-size: 0.875rem;
    opacity: 0.8;
}

/* ============================================
   FAQ
   ============================================ */
.section-faq {
    background: linear-gradient(180deg, var(--color-gray-50) 0%, var(--color-white) 100%);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-sm);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    transition: var(--transition-normal);
}

.faq-item:hover {
    box-shadow: var(--shadow-md);
}

.faq-item.active {
    box-shadow: var(--shadow-md);
}

.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: 1rem;
    font-weight: 500;
    color: var(--color-gray-800);
    text-align: left;
    transition: var(--transition-fast);
}

.faq-question:hover {
    background: var(--color-gray-50);
}

.faq-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    transition: var(--transition-fast);
}

.faq-item.active .faq-icon {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq-item.active .faq-answer {
    max-height: 500px;
    padding: 0 var(--spacing-lg) var(--spacing-md);
}

.faq-answer p {
    font-size: 0.95rem;
    color: var(--color-gray-600);
    line-height: 1.7;
}

/* ============================================
   页脚
   ============================================ */
.footer {
    background: var(--color-gray-800);
    color: var(--color-white);
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
}

.footer-logo {
    font-size: 1.25rem;
    font-weight: 600;
    display: block;
    margin-bottom: var(--spacing-sm);
}

.footer-desc {
    font-size: 0.875rem;
    color: var(--color-gray-400);
    line-height: 1.7;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
}

.footer-section h4 {
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-white);
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section ul li a {
    font-size: 0.875rem;
    color: var(--color-gray-400);
    transition: var(--transition-fast);
}

.footer-section ul li a:hover {
    color: var(--color-white);
}

.footer-bottom {
    border-top: 1px solid var(--color-gray-600);
    padding-top: var(--spacing-lg);
    text-align: center;
}

.copyright {
    font-size: 0.875rem;
    color: var(--color-gray-400);
    margin-bottom: 0.5rem;
}

.disclaimer {
    font-size: 0.75rem;
    color: var(--color-gray-600);
}

/* ============================================
   动画效果
   ============================================ */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

.slide-left {
    opacity: 0;
    transform: translateX(-50px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.slide-left.visible {
    opacity: 1;
    transform: translateX(0);
}

.slide-right {
    opacity: 0;
    transform: translateX(50px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.slide-right.visible {
    opacity: 1;
    transform: translateX(0);
}

/* ============================================
   响应式设计
   ============================================ */
@media (max-width: 1024px) {
    .mechanism-intro {
        grid-template-columns: 1fr;
    }
    
    .intro-chart {
        order: -1;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
    
    .footer-links {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 52px;
        left: 0;
        right: 0;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: var(--spacing-md);
        gap: var(--spacing-sm);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition-normal);
    }
    
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-stats {
        gap: var(--spacing-md);
    }
    
    .timeline-content::before {
        left: 20px;
    }
    
    .timeline-item:nth-child(odd),
    .timeline-item:nth-child(even) {
        flex-direction: row;
        padding-left: 60px;
        padding-right: 0;
    }
    
    .timeline-marker {
        left: 20px;
        transform: translateX(-50%);
    }
    
    .timeline-card {
        margin: 0;
        max-width: 100%;
    }
    
    .year {
        width: 48px;
        height: 48px;
        font-size: 0.75rem;
    }
    
    .flow-steps {
        flex-direction: column;
    }
    
    .flow-arrow {
        transform: rotate(90deg);
    }
    
    .mechanism-charts {
        grid-template-columns: 1fr;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-lg: 1rem;
        --spacing-xl: 1.5rem;
        --spacing-2xl: 2rem;
        --spacing-3xl: 3rem;
    }
    
    .hero {
        padding: 100px var(--spacing-md) 60px;
    }
    
    .about-grid,
    .diagnosis-grid,
    .data-grid {
        grid-template-columns: 1fr;
    }
    
    .charts-grid {
        grid-template-columns: 1fr;
    }
    
    .chart-card img {
        height: 200px;
    }
    
    .level-items {
        grid-template-columns: 1fr;
    }
}

/* ============================================
   打印样式
   ============================================ */
@media print {
    .navbar,
    .hero-scroll,
    .hero-cta {
        display: none;
    }
    
    .hero {
        min-height: auto;
        padding: 40px 20px;
    }
    
    .section {
        padding: 40px 0;
    }
    
    .fade-in,
    .slide-left,
    .slide-right {
        opacity: 1;
        transform: none;
    }
}