body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            margin: 0;
            padding: 0;
            background-color: #f5f5f5;
        }
        .header {
            background-color: #2c3e50;
            color: white;
            padding: 1rem;
            text-align: center;
        }
        .nav {
            background-color: #34495e;
            padding: 0.5rem;
            text-align: center;
        }
        .nav a {
            color: white;
            text-decoration: none;
            margin: 0 1rem;
        }
.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}
.content-with-sidebar {
    display: flex;
    align-items: flex-start;
    gap: 16px;
}
.main-content { flex: 1; }
.ad-sidebar {
    width: 280px;
}
.ad-card {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    padding: 10px;
    margin-bottom: 12px;
}
.ad-card img, .ad-card video {
    width: 100%;
    border-radius: 6px;
}
.ad-card h4 { margin: 8px 0; font-size: 14px; color: #2c3e50; }
.ad-card h4 { text-align: center; }
.ad-clickable { cursor: pointer; }
.ad-card a { display:block; color:#3498db; text-decoration:none; margin-top:6px; }
.ad-card a:hover { text-decoration:underline; }

.ad-popup-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}
.ad-popup {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.2);
    max-width: 640px;
    width: 90%;
    padding: 12px;
    position: relative;
}
.ad-popup-close {
    position: absolute;
    right: 8px;
    top: 8px;
    border: none;
    background: #eee;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    font-size: 18px;
    cursor: pointer;
}
.ad-popup-close:hover { background:#ddd; }
        .content-with-sidebar {
            display: flex;
            gap: 1.5rem;
        }
        .main-content {
            flex: 1 1 auto;
            min-width: 0;
        }
        .ad-sidebar {
            width: 280px;
            flex: 0 0 280px;
            display: flex;
            flex-direction: column;
            gap: 1rem;
        }
        .ad-card {
            background: white;
            border-radius: 8px;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
            overflow: hidden;
        }
        .ad-card .ad-title {
            padding: 0.5rem 0.75rem;
            font-size: 0.95rem;
            color: #2c3e50;
            border-bottom: 1px solid #ecf0f1;
        }
        .ad-media {
            width: 100%;
            display: block;
        }
        .ad-media img {
            width: 100%;
            height: auto;
            display: block;
        }
        .ad-media video {
            width: 100%;
            display: block;
        }
        .ad-card .ad-link {
            display: block;
            padding: 0.75rem;
            color: #3498db;
            text-decoration: none;
            border-top: 1px solid #ecf0f1;
            font-size: 0.9rem;
            text-align: center;
        }
        .ad-card .ad-link:hover { text-decoration: underline; }

        /* 弹窗广告 */
        .ad-popup-overlay {
            position: fixed;
            inset: 0;
            background: rgba(0,0,0,0.5);
            display: flex;
            align-items: center;
            justify-content: center;
            z-index: 1000;
        }
        .ad-popup {
            background: #fff;
            border-radius: 10px;
            box-shadow: 0 10px 25px rgba(0,0,0,0.2);
            width: min(90vw, 640px);
            max-height: 90vh;
            overflow: auto;
            position: relative;
        }
        .ad-popup-close {
            position: absolute;
            right: 8px;
            top: 8px;
            border: none;
            background: transparent;
            font-size: 24px;
            cursor: pointer;
            color: #7f8c8d;
        }
        .category-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 1.5rem;
            margin-top: 2rem;
        }
        .category-card {
            background: white;
            border-radius: 8px;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
            padding: 1.5rem;
            text-align: center;
            transition: transform 0.2s;
            cursor: pointer;
        }
        .category-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 4px 8px rgba(0,0,0,0.15);
        }
        .category-card img {
            width: 100%;
            height: 150px;
            object-fit: cover;
            border-radius: 4px;
            margin-bottom: 1rem;
        }
        .category-card h3 {
            margin: 0 0 0.5rem 0;
            color: #2c3e50;
        }
        .category-card p {
            color: #7f8c8d;
            font-size: 0.9rem;
        }
        .welcome-section {
            background: white;
            border-radius: 8px;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
            padding: 2rem;
            margin-bottom: 2rem;
            text-align: center;
        }
        .welcome-section h2 {
            color: #2c3e50;
            margin-top: 0;
        }
        .btn {
            display: inline-block;
            background-color: #3498db;
            color: white;
            padding: 0.75rem 1.5rem;
            text-decoration: none;
            border-radius: 4px;
            margin: 0.5rem;
            transition: background-color 0.2s;
        }
        .btn:hover {
            background-color: #2980b9;
        }
        .footer {
            background-color: #ecf0f1;
            padding: 2rem;
            text-align: center;
            margin-top: 2rem;
        }