* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7fa;
    color: #333;
    line-height: 1.6;
    padding: 20px;
}

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

header {
    text-align: center;
    margin: 30px 0 50px;
}

h1 {
    font-size: 2.5rem;
    color: #2c3e50;
    margin-bottom: 15px;
    position: relative;
    display: inline-block;
}

    h1:after {
        content: "";
        position: absolute;
        bottom: -10px;
        left: 50%;
        transform: translateX(-50%);
        width: 80px;
        height: 4px;
        background: #3498db;
        border-radius: 2px;
    }

.subtitle {
    font-size: 1.0rem;
    color: #7f8c8d;
    max-width: 700px;
    margin: 0 auto;
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 40px;
    margin-top: 30px;
}

.video-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

    .video-card:hover {
        transform: translateY(-5px);
        box-shadow: 0 15px 35px rgba(0, 0, 0, 0.12);
    }

.video-header {
    padding: 25px 25px 15px;
    background: linear-gradient(135deg, #3498db, #2c3e50);
    color: white;
}

.video-title {
    font-size: 1.5rem;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
}

    .video-title i {
        margin-right: 10px;
        font-size: 1.8rem;
    }

.video-description {
    font-size: 1.0rem;
    opacity: 0.9;
    line-height: 1.7;
}

.video-wrapper {
    position: relative;
    padding-top: 56.25%; /* 16:9 Aspect Ratio */
}

video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: block;
    background: #000;
    border-radius: 0 0 12px 12px;
}

.video-caption {
    padding: 20px;
    background: #f8f9fa;
    border-top: 1px solid #eee;
    font-size: 0.90rem;
    color: #555;
}

    .video-caption strong {
        color: #2c3e50;
    }

footer {
    text-align: center;
    margin-top: 60px;
    padding: 20px;
    color: #7f8c8d;
    font-size: 0.9rem;
    border-top: 1px solid #eee;
}

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

    h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }
}

/* ͼ±êÑùʽ */
.icon {
    display: inline-block;
    width: 24px;
    height: 24px;
    margin-right: 8px;
    vertical-align: middle;
}