/* 全局样式定义 */
body {
    margin: 0;
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #f5f7fa, #c3cfe2);
}

h1, h2, h3, h4 {
    font-weight: bold;
    color: #2c3e50;
}

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

.header {
    text-align: center;
    background: linear-gradient(135deg, #003366, #660099);
    color: white;
    padding: 100px 20px;
    position: relative;
}

.header h1 {
    font-size: 3rem;
    margin: 0;
}

.header p {
    font-size: 1.2rem;
    margin-top: 10px;
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('https://images.gptkong.com/demo/sample1.png') no-repeat center/cover;
    opacity: 0.2;
    z-index: -1;
}

.section {
    background: white;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    margin-bottom: 40px;
    overflow: hidden;
}

.section-header {
    background: linear-gradient(90deg, #ff7e5f, #feb47b);
    color: white;
    padding: 20px;
    text-align: center;
}

.section-content {
    padding: 20px;
}

.article {
    line-height: 1.8;
    font-size: 1rem;
}

.article pre {
    background: #f4f4f4;
    padding: 15px;
    border-radius: 5px;
    overflow-x: auto;
}

.article code {
    color: #e91e63;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.card {
    background: linear-gradient(135deg, #ffffff, #f0f0f0);
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease;
    overflow: hidden;
}

.card:hover {
    transform: scale(1.05);
}

.card img {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.card-content {
    padding: 15px;
}

.button {
    display: inline-block;
    background: linear-gradient(90deg, #3498db, #8e44ad);
    color: white;
    padding: 10px 20px;
    border-radius: 25px;
    text-decoration: none;
    transition: background 0.3s ease;
}

.button:hover {
    background: linear-gradient(90deg, #8e44ad, #3498db);
}

.footer {
    text-align: center;
    padding: 20px;
    background: linear-gradient(135deg, #003366, #660099);
    color: white;
    margin-top: 40px;
}

@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }

    .section {
        margin-bottom: 20px;
    }

    .card img {
        height: 150px;
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.fade-in {
    animation: fadeIn 2s ease-in-out;
}