/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans SC', sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

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

/* 导航栏样式 */
.navbar {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
    font-weight: 700;
    color: #3498db;
}

.nav-brand i {
    font-size: 1.8rem;
}

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

.nav-link {
    text-decoration: none;
    color: #555;
    font-weight: 500;
    padding: 8px 0;
    position: relative;
    transition: color 0.3s;
}

.nav-link:hover,
.nav-link.active {
    color: #3498db;
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: #3498db;
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: #3498db;
    cursor: pointer;
}

/* 主内容区 */
.main-content {
    margin-top: 80px;
}

/* 英雄区域 */
.hero-section {
    padding: 80px 0;
    background: linear-gradient(rgba(255, 255, 255, 0.9), rgba(255, 255, 255, 0.95));
    border-radius: 20px;
    margin: 20px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
}

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

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    color: #2c3e50;
    margin-bottom: 20px;
    background: linear-gradient(135deg, #3498db, #9b59b6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: #7f8c8d;
    margin-bottom: 10px;
}

.hero-desc {
    font-size: 1.1rem;
    color: #95a5a6;
    margin-bottom: 40px;
}

/* 下载框样式 */
.download-box {
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    margin-bottom: 40px;
}

.input-group {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.input-group input {
    flex: 1;
    padding: 15px 20px;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

.input-group input:focus {
    outline: none;
    border-color: #3498db;
}

.parse-btn {
    padding: 15px 30px;
    background: linear-gradient(135deg, #3498db, #2980b9);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.3s, box-shadow 0.3s;
}

.parse-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(52, 152, 219, 0.4);
}

.url-examples {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    font-size: 0.9rem;
    color: #7f8c8d;
}

.example {
    background: #f8f9fa;
    padding: 5px 15px;
    border-radius: 20px;
    border: 1px solid #e0e0e0;
}

/* 快速平台入口 */
.quick-platforms {
    margin-top: 40px;
}

.quick-platforms h3 {
    margin-bottom: 20px;
    color: #2c3e50;
}

.platform-icons {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
}

.platform-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    padding: 15px 20px;
    background: white;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s;
    min-width: 100px;
}

.platform-btn:hover {
    border-color: #3498db;
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.platform-btn i {
    font-size: 2rem;
    color: #3498db;
}

.platform-btn span {
    font-weight: 500;
    color: #2c3e50;
}

/* 解析结果区域 */
.result-section {
    background: white;
    border-radius: 20px;
    margin: 20px;
    padding: 40px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.result-header h2 {
    color: #2c3e50;
    font-size: 2rem;
}

.back-btn {
    padding: 10px 20px;
    background: #f8f9fa;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    color: #7f8c8d;
    cursor: pointer;
    transition: all 0.3s;
}

.back-btn:hover {
    background: #3498db;
    color: white;
    border-color: #3498db;
}

.video-preview {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

@media (max-width: 768px) {
    .video-preview {
        grid-template-columns: 1fr;
    }
}

.video-thumbnail {
    background: #f8f9fa;
    border-radius: 15px;
    overflow: hidden;
}

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

.video-info {
    padding: 20px;
}

.video-info h3 {
    margin-bottom: 15px;
    color: #2c3e50;
}

.video-meta {
    display: flex;
    gap: 20px;
    color: #7f8c8d;
    font-size: 0.9rem;
}

.download-options {
    background: #f8f9fa;
    padding: 30px;
    border-radius: 15px;
}

.quality-selector,
.format-selector {
    margin-bottom: 30px;
}

.quality-selector h4,
.format-selector h4 {
    margin-bottom: 15px;
    color: #2c3e50;
}

.quality-buttons,
.format-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.quality-btn,
.format-btn {
    padding: 10px 20px;
    background: white;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
}

.quality-btn.active,
.format-btn.active {
    background: #3498db;
    color: white;
    border-color: #3498db;
}

.quality-btn:hover:not(.active),
.format-btn:hover:not(.active) {
    border-color: #3498db;
}

.download-action {
    text-align: center;
}

.download-main-btn {
    padding: 15px 40px;
    background: linear-gradient(135deg, #2ecc71, #27ae60);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.3s, box-shadow 0.3s;
    margin-bottom: 20px;
}

.download-main-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(46, 204, 113, 0.4);
}

.download-tips {
    color: #7f8c8d;
    font-size: 0.9rem;
}

/* 批量下载 */
.batch-download {
    background: #f8f9fa;
    padding: 30px;
    border-radius: 15px;
    margin-top: 40px;
}

.batch-download h3 {
    margin-bottom: 20px;
    color: #2c3e50;
}

.batch-input {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.batch-input textarea {
    width: 100%;
    height: 150px;
    padding: 15px;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    font-family: inherit;
    font-size: 1rem;
    resize: vertical;
}

.batch-btn {
    align-self: flex-end;
    padding: 12px 30px;
    background: linear-gradient(135deg, #9b59b6, #8e44ad);
    color: white;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.3s;
}

.batch-btn:hover {
    transform: translateY(-2px);
}

/* 功能特色区域 */
.features-section {
    padding: 80px 0;
    background: white;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    color: #2c3e50;
    margin-bottom: 20px;
}

.section-subtitle {
    text-align: center;
    color: #7f8c8d;
    margin-bottom: 50px;
    font-size: 1.2rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-card {
    background: #f8f9fa;
    padding: 30px;
    border-radius: 15px;
    text-align: center;
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-10px);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, #3498db, #2980b9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
}

.feature-icon i {
    font-size: 2rem;
    color: white;
}

.feature-card h3 {
    margin-bottom: 15px;
    color: #2c3e50;
}

.feature-card p {
    color: #7f8c8d;
    line-height: 1.6;
}

/* 支持平台区域 */
.platforms-section {
    padding: 80px 0;
    background: #f8f9fa;
}

.platforms-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.platform-card {
    background: white;
    padding: 30px;
    border-radius: 15px;
    text-align: center;
    transition: all 0.3s;
}

.platform-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.platform-logo {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    font-size: 2.5rem;
}

.platform-logo.douyin { background: #000; color: white; }
.platform-logo.kuaishou { background: #ff6600; color: white; }
.platform-logo.bilibili { background: #fb7299; color: white; }
.platform-logo.youtube { background: #ff0000; color: white; }
.platform-logo.weibo { background: #e6162d; color: white; }
.platform-logo.xiaohongshu { background: #ff2442; color: white; }
.platform-logo.instagram { background: linear-gradient(45deg, #405de6, #5851db, #833ab4, #c13584, #e1306c, #fd1d1d); color: white; }
.platform-logo.twitter { background: #1da1f2; color: white; }

.platform-card h3 {
    margin-bottom: 10px;
    color: #2c3e50;
}

.platform-card p {
    color: #7f8c8d;
    font-size: 0.9rem;
}

.more-platforms {
    text-align: center;
    color: #95a5a6;
    font-size: 0.9rem;
    padding: 20px;
    background: white;
    border-radius: 10px;
}

/* 使用指南区域 */
.guide-section {
    padding: 80px 0;
    background: white;
}

.guide-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.step-card {
    background: #f8f9fa;
    padding: 30px;
    border-radius: 15px;
    text-align: center;
    position: relative;
}

.step-number {
    position: absolute;
    top: -15px;
    left: -15px;
    width: 40px;
    height: 40px;
    background: #3498db;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.2rem;
}

.step-card h3 {
    margin: 20px 0 15px;
    color: #2c3e50;
}

.step-card p {
    color: #7f8c8d;
    margin-bottom: 20px;
}

.step-img {
    width: 80px;
    height: 80px;
    background: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto;
    font-size: 2rem;
    color: #3498db;
}

/* 常见问题区域 */
.faq-section {
    padding: 80px 0;
    background: #f8f9fa;
}

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

.faq-item {
    background: white;
    border-radius: 10px;
    margin-bottom: 15px;
    overflow: hidden;
}

.faq-question {
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    border-bottom: 1px solid #e0e0e0;
}

.faq-question h3 {
    color: #2c3e50;
    font-size: 1.1rem;
}

.faq-question i {
    color: #3498db;
    transition: transform 0.3s;
}

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

.faq-answer {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s, padding 0.3s;
}

.faq-item.active .faq-answer {
    padding: 20px;
    max-height: 200px;
}

.faq-answer p {
    color: #7f8c8d;
    line-height: 1.6;
}

/* 页脚样式 */
.footer {
    background: #2c3e50;
    color: white;
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h3 {
    color: white;
    margin-bottom: 20px;
    font-size: 1.2rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 10px;
}

.footer-section a {
    color: #bdc3c7;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: #3498db;
}

.footer-section i {
    margin-right: 10px;
    color: #3498db;
}

.social-links {
    display: flex;
    gap: 15px;
    margin-top: 20px;
}

.social-links a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    color: white;
    font-size: 1.2rem;
    transition: all 0.3s;
}

.social-links a:hover {
    background: #3498db;
    transform: translateY(-3px);
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: #bdc3c7;
    font-size: 0.9rem;
}

.footer-bottom p {
    margin-bottom: 10px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 20px;
        box-shadow: 0 5px 20px rgba(0,0,0,0.1);
        display: none;
    }
    
    .nav-menu.show {
        display: flex;
    }
    
    .nav-toggle {
        display: block;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .input-group {
        flex-direction: column;
    }
    
    .platform-icons {
        justify-content: center;
    }
    
    .platform-btn {
        min-width: 80px;
        padding: 10px 15px;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .video-preview {
        grid-template-columns: 1fr;
    }
    
    .features-grid,
    .platforms-grid,
    .guide-steps {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 1.8rem;
    }
    
    .feature-card,
    .platform-card,
    .step-card {
        padding: 20px;
    }
    
    .quality-buttons,
    .format-buttons {
        justify-content: center;
    }
    
    .quality-btn,
    .format-btn {
        flex: 1;
        min-width: 80px;
        text-align: center;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.feature-card,
.platform-card,
.step-card {
    animation: fadeIn 0.6s ease-out;
}

/* 加载动画 */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid #f3f3f3;
    border-top: 3px solid #3498db;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}