:root {
    --primary: #2E8B57;
    --primary-light: #3CB371;
    --primary-dark: #1F6B48;
    --secondary: #8B4513;
    --accent: #FFA500;
    --light: #F8F9FA;
    --dark: #212529;
    --gray: #6C757D;
    --light-gray: #E9ECEF;
    --border-radius: 12px;
    --shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

body {
    background-color: #f5f7f9;
    color: var(--dark);
    line-height: 1.6;
    padding-bottom: 60px;
}

/* 导航栏样式 */
.navbar {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    padding: 0.8rem 2rem;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.logo-icon {
    font-size: 2.2rem;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    padding: 0.5rem 0.8rem;
    border-radius: 6px;
}

.nav-links a:hover {
    background: rgba(255, 255, 255, 0.15);
}

/* 主容器 */
.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1.5rem;
}

/* 英雄区域 */
.hero {
    background: linear-gradient(rgba(46, 139, 87, 0.9), rgba(31, 107, 72, 0.9));
    color: white;
    padding: 3.5rem 2.5rem;
    border-radius: var(--border-radius);
    text-align: center;
    margin-bottom: 3rem;
    box-shadow: var(--shadow);
}

.hero-title {
    font-size: 2.8rem;
    margin-bottom: 1.2rem;
    font-weight: 700;
}

.hero-subtitle {
    font-size: 1.3rem;
    max-width: 800px;
    margin: 0 auto 2rem;
    opacity: 0.95;
}

.mt-2 {
    margin-top: 2rem;
}

/* 按钮样式 */
.btn {
    display: inline-block;
    background-color: var(--accent);
    color: white;
    padding: 0.9rem 1.8rem;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.btn:hover {
    background-color: #FF8C00;
    transform: translateY(-3px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.btn-outline {
    background: transparent;
    border: 2px solid white;
    margin-left: 1rem;
}

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

/* 功能卡片 */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.feature-card {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 2.5rem 2rem;
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 25px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    font-size: 3.2rem;
    color: var(--primary);
    margin-bottom: 1.5rem;
}

.feature-title {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--primary-dark);
}

.feature-text {
    color: var(--gray);
    line-height: 1.7;
}

/* 上传区域 */
.upload-section {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 2.5rem;
    box-shadow: var(--shadow);
    margin-bottom: 3rem;
}

.section-title {
    text-align: center;
    margin-bottom: 2.5rem;
    color: var(--primary-dark);
    font-size: 2rem;
    position: relative;
    padding-bottom: 0.8rem;
}

.section-title:after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: var(--accent);
    border-radius: 2px;
}

.upload-form {
    display: flex;
    flex-direction: column;
    gap: 1.8rem;
    max-width: 700px;
    margin: 0 auto;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.7rem;
}

.form-label {
    font-weight: 600;
    color: var(--primary-dark);
    font-size: 1.1rem;
}

.form-input,
.form-textarea,
.form-select {
    padding: 1rem;
    border: 2px solid var(--light-gray);
    border-radius: 8px;
    font-size: 1rem;
    transition: var(--transition);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
    border-color: var(--primary);
    outline: none;
    box-shadow: 0 0 0 3px rgba(46, 139, 87, 0.2);
}

.form-textarea {
    min-height: 120px;
    resize: vertical;
}

/* 视频区域 */
.videos-section {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 2.5rem;
    box-shadow: var(--shadow);
}

.mt-3 {
    margin-top: 3rem;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

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

.video-card {
    background-color: var(--light);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.video-thumb {
    height: 200px;
    overflow: hidden;
    position: relative;
    background: linear-gradient(45deg, var(--primary-light), var(--primary-dark));
    display: flex;
    align-items: center;
    justify-content: center;
}

.video-thumb-icon {
    font-size: 4.5rem;
    color: white;
    opacity: 0.8;
    transition: var(--transition);
}

.video-duration {
    position: absolute;
    bottom: 12px;
    right: 12px;
    background-color: rgba(0, 0, 0, 0.7);
    color: white;
    padding: 0.3rem 0.7rem;
    border-radius: 4px;
    font-size: 0.85rem;
}

.video-info {
    padding: 1.8rem;
}

.video-title {
    margin-bottom: 0.8rem;
    color: var(--primary-dark);
    font-size: 1.3rem;
    line-height: 1.4;
}

.video-description {
    color: var(--gray);
    margin-bottom: 1.2rem;
    line-height: 1.5;
}

.video-meta {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--gray);
    margin-bottom: 1.5rem;
}

.video-meta span {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.video-actions {
    display: flex;
    gap: 0.8rem;
}

.action-btn {
    flex: 1;
    padding: 0.7rem;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
    text-align: center;
    text-decoration: none;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

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

.download-btn:hover {
    background-color: var(--primary-dark);
}

.preview-btn {
    background-color: var(--light-gray);
    color: var(--dark);
}

.preview-btn:hover {
    background-color: #DEE2E6;
}

.no-videos {
    grid-column: 1 / -1;
    text-align: center;
    padding: 3rem;
    color: var(--gray);
}

.no-videos i {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.no-videos h3 {
    margin-bottom: 0.5rem;
    color: var(--primary-dark);
}

/* 页脚样式 */
footer {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary));
    color: white;
    padding: 3rem 2rem 1.5rem;
    margin-top: 4rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2.5rem;
}

.footer-section h3 {
    font-size: 1.4rem;
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 0.8rem;
}

.footer-section h3:after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 3px;
    background-color: var(--accent);
    border-radius: 2px;
}

.footer-section p {
    margin-bottom: 1.2rem;
    opacity: 0.9;
}

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

.footer-links li {
    margin-bottom: 0.8rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.footer-links a:hover {
    color: white;
    transform: translateX(5px);
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.social-icons {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

.social-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 42px;
    height: 42px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    transition: var(--transition);
    color: white;
    text-decoration: none;
    font-size: 1.2rem;
}

.social-icon:hover {
    background-color: var(--accent);
    transform: translateY(-3px);
}

.copyright {
    text-align: center;
    margin-top: 3rem;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    opacity: 0.8;
}

/* 消息提示 */
.message {
    padding: 1rem;
    margin: 1rem 0;
    border-radius: var(--border-radius);
    text-align: center;
}

.message.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.message.error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

/* 响应式设计 */
@media (max-width: 992px) {
    .hero-title {
        font-size: 2.4rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
}

@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        padding: 1rem;
    }
    
    .logo {
        margin-bottom: 1rem;
    }
    
    .nav-links {
        gap: 1rem;
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .hero {
        padding: 2.5rem 1.5rem;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .section-header {
        flex-direction: column;
        text-align: center;
    }
    
    .videos-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer-section h3:after {
        left: 50%;
        transform: translateX(-50%);
    }
    
    .contact-info {
        align-items: center;
    }
    
    .social-icons {
        justify-content: center;
    }
    
    .btn-outline {
        margin-left: 0;
        margin-top: 1rem;
    }
}