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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

nav {
    background: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

nav h1 {
    font-size: 1.5rem;
    color: #667eea;
}

.container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.card {
    background: white;
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.card h1, .card h2, .card h3 {
    margin-bottom: 1rem;
    color: #667eea;
}

.card p {
    color: #666;
    margin-bottom: 1.5rem;
}

.btn-primary, .btn-secondary, .btn-danger {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-primary {
    background: #667eea;
    color: white;
}

.btn-primary:hover {
    background: #5568d3;
}

.btn-secondary {
    background: #e2e8f0;
    color: #333;
}

.btn-secondary:hover {
    background: #cbd5e0;
}

.btn-danger {
    background: #f56565;
    color: white;
}

.btn-danger:hover {
    background: #e53e3e;
}

.key-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    margin: 1rem 0;
    background: #f7fafc;
    border-radius: 4px;
    border-left: 4px solid #667eea;
}

.key-display {
    display: flex;
    gap: 1rem;
    align-items: center;
    margin-top: 1rem;
    padding: 1rem;
    background: #f7fafc;
    border-radius: 4px;
}

.key-display code {
    flex: 1;
    font-family: 'Courier New', monospace;
    word-break: break-all;
}

textarea {
    width: 100%;
    min-height: 150px;
    padding: 1rem;
    border: 1px solid #e2e8f0;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    margin-bottom: 1rem;
    resize: vertical;
}

.success {
    padding: 1rem;
    background: #c6f6d5;
    border-left: 4px solid #48bb78;
    border-radius: 4px;
    margin-top: 1rem;
}

.error {
    padding: 1rem;
    background: #fed7d7;
    border-left: 4px solid #f56565;
    border-radius: 4px;
    margin-top: 1rem;
}

@media (max-width: 768px) {
    .container {
        padding: 0 0.5rem;
    }
    
    .card {
        padding: 1rem;
    }
    
    .key-item {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
}