/* ===== 基础样式 ===== */
:root {
    --primary-color: #00A7E0;
    --primary-dark: #0088B8;
    --primary-light: #33B8E7;
    --text-dark: #1a1a2e;
    --text-gray: #6b7280;
    --text-light: #9ca3af;
    --bg-white: #ffffff;
    --bg-light: #f8fafc;
    --bg-gray: #f1f5f9;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-white);
    color: var(--text-dark);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: var(--transition);
    background: transparent;
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-md);
    padding: 12px 0;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo img {
    height: 40px;
    width: auto;
    filter: brightness(0) invert(1);
    transition: var(--transition);
}

.navbar.scrolled .logo img {
    filter: none;
}

.nav-links {
    display: flex;
    gap: 32px;
}

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

.navbar.scrolled .nav-links a {
    color: var(--text-dark);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: var(--transition);
}

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

.nav-btn {
    background: var(--primary-color);
    color: white;
    padding: 10px 24px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: 500;
    font-size: 14px;
    transition: var(--transition);
}

.nav-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-btn span {
    width: 24px;
    height: 2px;
    background: white;
    transition: var(--transition);
}

.navbar.scrolled .mobile-menu-btn span {
    background: var(--text-dark);
}

/* ===== Hero 区域 ===== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.hero-video-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
}

.hero-video-bg video {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(0, 167, 224, 0.85) 0%, rgba(0, 60, 100, 0.9) 100%);
}

.hero-content {
    text-align: center;
    color: white;
    max-width: 900px;
    padding: 120px 24px 80px;
    z-index: 1;
}

.hero-badge {
    display: inline-block;
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    padding: 8px 20px;
    border-radius: 50px;
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 24px;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.hero h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 24px;
}

.hero h1 .highlight {
    color: #7dd3fc;
    text-shadow: 0 0 30px rgba(125, 211, 252, 0.5);
}

.hero-desc {
    font-size: 18px;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 32px;
    line-height: 1.8;
}

.hero-desc strong {
    color: white;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 48px;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    border-radius: var(--radius-sm);
    font-size: 16px;
    font-weight: 500;
    text-decoration: none;
    transition: var(--transition);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-outline {
    background: transparent;
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.5);
}

.btn-outline:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: white;
}

.btn-full {
    width: 100%;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 48px;
    flex-wrap: wrap;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.stat-label {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.7);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.stat-value {
    font-size: 16px;
    font-weight: 600;
    color: white;
}

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

.scroll-indicator span {
    display: block;
    width: 24px;
    height: 40px;
    border: 2px solid rgba(255, 255, 255, 0.5);
    border-radius: 12px;
    position: relative;
}

.scroll-indicator span::before {
    content: '';
    position: absolute;
    top: 8px;
    left: 50%;
    width: 4px;
    height: 8px;
    background: white;
    border-radius: 2px;
    transform: translateX(-50%);
    animation: scroll 2s infinite;
}

@keyframes scroll {
    0%, 100% { opacity: 1; top: 8px; }
    50% { opacity: 0.3; top: 20px; }
}

/* ===== 通用标题样式 ===== */
.section-title {
    font-size: clamp(2rem, 4vw, 2.5rem);
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
    color: var(--text-dark);
}

.section-desc {
    font-size: 18px;
    color: var(--text-gray);
    text-align: center;
    margin-bottom: 48px;
}

/* ===== 问题解决区域 ===== */
.problems {
    padding: 100px 0;
    background: var(--bg-light);
}

.problems-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.problem-card {
    background: white;
    padding: 32px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

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

.problem-icon {
    font-size: 40px;
    margin-bottom: 20px;
}

.problem-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.problem-card p {
    font-size: 15px;
    color: var(--text-gray);
    line-height: 1.7;
}

/* ===== 案例展示区域 ===== */
.showcase {
    padding: 100px 0;
    background: var(--bg-white);
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 16px;
}

.video-item {
    aspect-ratio: 9/16;
    border-radius: var(--radius-md);
    overflow: hidden;
    position: relative;
    background: var(--bg-gray);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.video-item:hover {
    transform: scale(1.02);
    box-shadow: var(--shadow-xl);
}

.video-item:hover .video-info {
    opacity: 1;
    transform: translateY(0);
}

.video-item video {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.video-info {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 16px;
    background: linear-gradient(to top, rgba(0, 0, 0, 0.85) 0%, rgba(0, 0, 0, 0.5) 70%, transparent 100%);
    color: white;
    opacity: 0;
    transform: translateY(10px);
    transition: var(--transition);
}

.video-info h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 8px;
    color: white;
}

.video-tags {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.video-tag {
    display: inline-block;
    padding: 3px 8px;
    background: rgba(0, 167, 224, 0.8);
    color: white;
    font-size: 11px;
    font-weight: 500;
    border-radius: 4px;
    backdrop-filter: blur(5px);
}

/* ===== 服务内容区域 ===== */
.services {
    padding: 100px 0;
    background: var(--bg-light);
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.service-card {
    background: white;
    padding: 36px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 0;
    background: var(--primary-color);
    transition: var(--transition);
}

.service-card:hover::before {
    height: 100%;
}

.service-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.service-card.featured {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
}

.service-card.featured h3,
.service-card.featured p {
    color: white;
}

.service-icon {
    font-size: 40px;
    margin-bottom: 20px;
}

.service-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.service-card p {
    font-size: 15px;
    color: var(--text-gray);
    line-height: 1.7;
}

.service-tags {
    display: flex;
    gap: 8px;
    margin-top: 16px;
    flex-wrap: wrap;
}

.tag {
    display: inline-block;
    padding: 4px 12px;
    background: var(--bg-light);
    color: var(--primary-color);
    font-size: 12px;
    font-weight: 500;
    border-radius: 50px;
}

/* ===== 优势区域 ===== */
.advantages {
    padding: 100px 0;
    background: var(--bg-white);
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.advantage-card {
    background: var(--bg-light);
    padding: 36px;
    border-radius: var(--radius-lg);
    transition: var(--transition);
    border: 2px solid transparent;
}

.advantage-card:hover {
    border-color: var(--primary-color);
    background: white;
    box-shadow: var(--shadow-lg);
}

.advantage-category {
    display: inline-block;
    padding: 4px 12px;
    background: var(--primary-color);
    color: white;
    font-size: 12px;
    font-weight: 500;
    border-radius: 50px;
    margin-bottom: 16px;
}

.advantage-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.advantage-card p {
    font-size: 15px;
    color: var(--text-gray);
    line-height: 1.7;
}

/* ===== 联系区域 ===== */
.contact {
    padding: 100px 0;
    background: linear-gradient(135deg, var(--bg-light) 0%, var(--bg-white) 100%);
}

.contact-wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: start;
}

.contact-info h2 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-dark);
}

.contact-info > p {
    font-size: 16px;
    color: var(--text-gray);
    margin-bottom: 32px;
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: 20px;
    margin-bottom: 32px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 15px;
    color: var(--text-dark);
}

.contact-icon {
    font-size: 20px;
}

.contact-form-wrapper {
    background: white;
    padding: 40px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-group label {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-dark);
}

.form-group input,
.form-group textarea {
    padding: 14px 16px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 15px;
    font-family: inherit;
    transition: var(--transition);
    background: var(--bg-light);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    background: white;
    box-shadow: 0 0 0 3px rgba(0, 167, 224, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

/* ===== 页脚 ===== */
.footer {
    padding: 60px 0 40px;
    background: var(--text-dark);
    color: white;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 24px;
    text-align: center;
}

.footer-logo img {
    height: 36px;
    filter: brightness(0) invert(1);
}

.footer-links {
    display: flex;
    gap: 32px;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    font-size: 14px;
    transition: var(--transition);
}

.footer-links a:hover {
    color: white;
}

.footer-copyright {
    color: rgba(255, 255, 255, 0.5);
    font-size: 13px;
}

.footer-copyright p {
    margin: 4px 0;
}

/* ===== 响应式设计 ===== */
@media (max-width: 1024px) {
    .video-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .contact-wrapper {
        grid-template-columns: 1fr;
        gap: 40px;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 24px;
        gap: 16px;
        box-shadow: var(--shadow-lg);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .nav-links a {
        color: var(--text-dark);
    }
    
    .nav-btn {
        display: none;
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero-stats {
        gap: 24px;
    }
    
    .video-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .problems-grid,
    .services-grid,
    .advantages-grid {
        grid-template-columns: 1fr;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
        gap: 16px;
    }
}

@media (max-width: 480px) {
    .hero-buttons {
        flex-direction: column;
    }
    
    .hero-buttons .btn {
        width: 100%;
    }
    
    .stat-item {
        flex: 1;
        min-width: 100px;
    }
    
    .contact-form-wrapper {
        padding: 24px;
    }
}

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

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

/* 平滑滚动时的链接高亮 */
.nav-links a.active {
    color: var(--primary-color) !important;
}

.nav-links a.active::after {
    width: 100%;
}