* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

main {
    padding: 30px;
}

.card {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 25px;
    margin-bottom: 20px;
    border-left: 4px solid #667eea;
}

.card h2 {
    color: #667eea;
    margin-bottom: 15px;
    font-size: 1.5rem;
}

.card ul {
    list-style: none;
    padding-left: 0;
}

.card ul li {
    padding: 8px 0;
    padding-left: 25px;
    position: relative;
}

.card ul li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #667eea;
    font-weight: bold;
}

.btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 12px 30px;
    font-size: 1rem;
    border-radius: 6px;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(102, 126, 234, 0.4);
}

.btn:active {
    transform: translateY(0);
}

#output {
    margin-top: 15px;
    font-size: 1.1rem;
    color: #667eea;
    min-height: 24px;
}

footer {
    background: #f8f9fa;
    padding: 20px;
    text-align: center;
    color: #666;
    font-size: 0.9rem;
}

@media (max-width: 600px) {
    header h1 {
        font-size: 1.8rem;
    }
    
    main {
        padding: 20px;
    }
}