/* 全局重置和基础变量 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #E91E63;
    --primary-dark: #C2185B;
    --primary-light: #F48FB1;
    --secondary: #FFC107;
    --accent: #9C27B0;
    --bg-main: #FAFAFA;
    --bg-card: #FFFFFF;
    --bg-dark: #1A1A1A;
    --text-primary: #212121;
    --text-secondary: #757575;
    --text-light: #FFFFFF;
    --border: #E0E0E0;
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.12);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.16);
    --radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: var(--bg-main);
    color: var(--text-primary);
    line-height: 1.6;
    font-size: 16px;
}

.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 头部导航 */
.app-header {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
}

.logo-section {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-shrink: 0;
}

.logo-image {
    width: 50px;
    height: 50px;
    border-radius: 10px;
    overflow: hidden;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    display: flex;
    align-items: center;
    justify-content: center;
}

.logo-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.logo-text {
    display: flex;
    flex-direction: column;
}

.site-logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    line-height: 1.2;
}

.site-tagline {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.125rem;
}

.header-nav {
    display: flex;
    gap: 0.5rem;
    flex: 1;
    justify-content: center;
}

.nav-item {
    padding: 0.625rem 1.25rem;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    border-radius: 8px;
    transition: var(--transition);
    position: relative;
}

.nav-item:hover {
    background: var(--bg-main);
    color: var(--primary);
}

.nav-item.active {
    color: var(--primary);
    background: rgba(233, 30, 99, 0.1);
}

.header-actions {
    display: flex;
    gap: 0.75rem;
    flex-shrink: 0;
}

.btn-login,
.btn-register {
    padding: 0.625rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9375rem;
}

.btn-login {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-login:hover {
    background: var(--bg-main);
    border-color: var(--primary);
    color: var(--primary);
}

.btn-register {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: var(--text-light);
}

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

/* 主内容区域 */
.app-main {
    flex: 1;
}

/* Hero区域 */
.hero-banner {
    background: linear-gradient(135deg, #FFF5F8 0%, #F3E5F5 100%);
    padding: 4rem 2rem;
}

.hero-content {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-text {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    color: var(--text-primary);
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn-hero {
    padding: 1rem 2rem;
    border-radius: 10px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    display: inline-block;
}

.btn-hero.primary {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: var(--text-light);
}

.btn-hero.primary:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.btn-hero.secondary {
    background: var(--bg-card);
    color: var(--primary);
    border: 2px solid var(--primary);
}

.btn-hero.secondary:hover {
    background: var(--primary);
    color: var(--text-light);
}

.hero-media {
    position: relative;
}

.video-preview-box {
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    background: var(--bg-dark);
}

.preview-video {
    width: 100%;
    height: auto;
    display: block;
}

/* 通用区块样式 */
.section-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
}

.section-header {
    text-align: center;
    margin-bottom: 3rem;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

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

/* 视频网格 */
.featured-videos {
    padding: 4rem 0;
    background: var(--bg-card);
}

.videos-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
}

.video-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    overflow: hidden;
    transition: var(--transition);
    border: 1px solid var(--border);
}

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

.card-thumbnail {
    position: relative;
    width: 100%;
    padding-top: 56.25%;
    background: var(--bg-dark);
    overflow: hidden;
}

.thumbnail-img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.video-card:hover .thumbnail-img {
    transform: scale(1.05);
}

.play-badge {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    opacity: 0;
    transition: var(--transition);
    z-index: 2;
}

.video-card:hover .play-badge {
    opacity: 1;
}

.duration-label {
    position: absolute;
    bottom: 0.75rem;
    right: 0.75rem;
    background: rgba(0, 0, 0, 0.8);
    color: var(--text-light);
    padding: 0.25rem 0.75rem;
    border-radius: 6px;
    font-size: 0.875rem;
    z-index: 2;
}

.card-body {
    padding: 1.5rem;
}

.card-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-description {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1rem;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-meta {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.meta-item {
    display: flex;
    align-items: center;
}

.meta-text {
    color: var(--text-secondary);
}

/* 功能特色 */
.platform-features {
    padding: 4rem 0;
    background: var(--bg-main);
}

.features-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.feature-box {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: var(--radius);
    text-align: center;
    transition: var(--transition);
    border: 1px solid var(--border);
}

.feature-box:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-light);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.feature-name a {
    color: var(--text-primary);
    text-decoration: none;
    transition: var(--transition);
}

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

.feature-desc {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* CTA区域 */
.cta-section {
    padding: 4rem 0;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: var(--text-light);
}

.cta-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.cta-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.cta-text {
    font-size: 1.125rem;
    margin-bottom: 2rem;
    opacity: 0.95;
}

.cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn-cta {
    padding: 1rem 2.5rem;
    border-radius: 10px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    display: inline-block;
}

.btn-cta.primary {
    background: var(--text-light);
    color: var(--primary);
}

.btn-cta.primary:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.btn-cta.secondary {
    background: transparent;
    color: var(--text-light);
    border: 2px solid var(--text-light);
}

.btn-cta.secondary:hover {
    background: var(--text-light);
    color: var(--primary);
}

/* 页脚 */
.app-footer {
    background: var(--bg-dark);
    color: var(--text-light);
    padding: 3rem 0 1.5rem;
}

.footer-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 3rem;
    margin-bottom: 2rem;
}

.footer-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--primary-light), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.footer-desc {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.9375rem;
}

.footer-heading {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-light);
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: var(--transition);
    font-size: 0.9375rem;
}

.footer-links a:hover {
    color: var(--primary-light);
    padding-left: 0.5rem;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.copyright {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.875rem;
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .hero-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .section-title {
        font-size: 2rem;
    }
}

@media (max-width: 768px) {
    .header-content {
        flex-wrap: wrap;
        padding: 1rem;
    }

    .header-nav {
        order: 3;
        width: 100%;
        justify-content: flex-start;
        overflow-x: auto;
        padding: 0.5rem 0;
    }

    .hero-banner {
        padding: 2rem 1rem;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-description {
        font-size: 1rem;
    }

    .section-container {
        padding: 0 1rem;
    }

    .section-title {
        font-size: 1.75rem;
    }

    .videos-grid {
        grid-template-columns: 1fr;
    }

    .features-list {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 1.75rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .btn-hero,
    .btn-cta {
        padding: 0.875rem 1.5rem;
        font-size: 0.9375rem;
    }
}

/* 性能优化 */
.video-card,
.feature-box {
    will-change: transform;
}

img {
    image-rendering: -webkit-optimize-contrast;
    image-rendering: crisp-edges;
}