* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Arial', sans-serif;
}

body {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    line-height: 1.6;
}

h1 {
    color: #2c3e50;
    margin-bottom: 2rem;
    text-align: center;
}

ul {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1.5rem;
}

li a {
    display: block;
    padding: 1.5rem;
    background: #f8f9fa;
    border-radius: 8px;
    text-decoration: none;
    color: #34495e;
    font-weight: 500;
    transition: all 0.3s ease;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

li a:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    background: #3498db;
    color: white;
}

.error-container {
    text-align: center;
    padding: 5rem 2rem;
}

.error-container h1 {
    font-size: 5rem;
    color: #e74c3c;
    margin-bottom: 1rem;
}

.btn {
    display: inline-block;
    padding: 0.8rem 2rem;
    background: #3498db;
    color: white;
    text-decoration: none;
    border-radius: 4px;
    margin-top: 1rem;
    transition: background 0.3s ease;
}

.btn:hover {
    background: #2980b9;
}