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

body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    background-color: #f8f9fa;
    color: #333;
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
    flex: 1;
}

header {
    text-align: center;
    margin-bottom: 50px;
    padding: 20px 0;
}

.main-title {
    font-size: 2.8rem;
    font-weight: 700;
    margin-bottom: 15px;
    color: #2c3e50;
    letter-spacing: -0.5px;
}

.subtitle {
    font-size: 1.2rem;
    color: #7f8c8d;
    max-width: 600px;
    margin: 0 auto;
    font-weight: 300;
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-bottom: 60px;
    justify-items: center;
}

.video-item {
    background: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
    width: 100%;
    max-width: 350px;
}

/* 使用伪元素平衡第二行布局 */
.video-grid::after {
    content: "";
    width: 0;
    grid-column: 3;
}

/* 确保第二行的两个视频居中 */
.video-item:nth-child(4) {
    grid-column: 1;
}

.video-item:nth-child(5) {
    grid-column: 2;
}

.video-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.12);
}

.video-link {
    text-decoration: none;
    color: inherit;
    display: block;
}

.video-thumbnail {
    position: relative;
    width: 100%;
    height: 0;
    padding-bottom: 60%;
    overflow: hidden;
}

.thumbnail-image {
    position: absolute;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    transition: transform 0.5s ease;
}

.video-item:hover .thumbnail-image {
    transform: scale(1.05);
}

.play-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    background-color: rgba(255, 255, 255, 0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    opacity: 0;
}

.video-item:hover .play-button {
    opacity: 1;
}

.play-button i {
    color: #2c3e50;
    font-size: 20px;
    margin-left: 4px;
}

.video-duration {
    position: absolute;
    bottom: 12px;
    right: 12px;
    background: rgba(0, 0, 0, 0.7);
    color: #fff;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
}

.video-info {
    padding: 20px;
}

.video-info h3 {
    font-size: 1.3rem;
    margin-bottom: 8px;
    color: #2c3e50;
    font-weight: 600;
}

.video-info p {
    color: #7f8c8d;
    margin-bottom: 15px;
    font-size: 0.95rem;
    line-height: 1.5;
}

.video-meta {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    color: #95a5a6;
}

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

.video-meta i {
    margin-right: 5px;
}

footer {
    text-align: center;
    padding: 20px 0;
    color: #7f8c8d;
    font-size: 0.9rem;
    border-top: 1px solid #eaecee;
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .container {
        padding: 30px 20px;
    }
    
    .main-title {
        font-size: 2.4rem;
    }
    
    .video-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 25px;
        justify-content: center;
    }
    
    /* 在中等屏幕上取消第二行的特殊处理 */
    .video-item:nth-child(4),
    .video-item:nth-child(5) {
        grid-column: auto;
    }
    
    /* 在中等屏幕隐藏伪元素 */
    .video-grid::after {
        display: none;
    }
}

@media (max-width: 768px) {
    .container {
        padding: 25px 15px;
    }
    
    .main-title {
        font-size: 2rem;
    }
    
    .subtitle {
        font-size: 1.1rem;
    }
    
    .video-grid {
        grid-template-columns: 1fr;
        gap: 20px;
        max-width: 500px;
        margin: 0 auto 40px;
    }
    
    .video-info {
        padding: 15px;
    }
    
    .video-info h3 {
        font-size: 1.2rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 20px 10px;
    }
    
    header {
        margin-bottom: 30px;
    }
    
    .main-title {
        font-size: 1.8rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .play-button {
        opacity: 1;
        width: 50px;
        height: 50px;
    }
}