body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f9;
    color: #333;
}

header {
    background-color: #2c3e50;
    color: #fff;
    padding: 20px 0;
    text-align: center;
}

header h1 {
    margin: 0;
    font-size: 2.5em;
}

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

.category-section {
    background: #fff;
    margin-bottom: 20px;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.category-title {
    border-bottom: 2px solid #3498db;
    padding-bottom: 10px;
    margin-bottom: 20px;
    color: #2c3e50;
    font-size: 1.5em;
}

.file-list {
    list-style: none;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 15px;
}

.file-list li {
    background: #ecf0f1;
    border-radius: 4px;
    transition: background 0.3s;
}

.file-list li:hover {
    background: #e0e6ed;
}

.file-list a {
    display: block;
    padding: 15px;
    text-decoration: none;
    color: #2980b9;
    font-weight: 500;
}

.file-list a:hover {
    color: #1abc9c;
}

footer {
    text-align: center;
    padding: 20px;
    margin-top: 40px;
    color: #7f8c8d;
    font-size: 0.9em;
}