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

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

.top-nav {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-logo {
    font-size: 1.2rem;
    font-weight: 700;
    color: #667eea;
    text-decoration: none;
    transition: transform 0.2s;
}

.nav-logo:hover {
    transform: scale(1.05);
}

.nav-links {
    display: flex;
    gap: 1rem;
}

.nav-link {
    padding: 0.5rem 1rem;
    border-radius: 8px;
    text-decoration: none;
    color: #495057;
    font-weight: 600;
    transition: all 0.2s;
}

.nav-link:hover {
    background: #f8f9fa;
    color: #667eea;
}

.nav-link.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    background: white;
    border-radius: 16px;
    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: 2rem;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

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

.controls {
    padding: 2rem;
    background: #f8f9fa;
    border-bottom: 1px solid #e9ecef;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
}

.control-group {
    margin-bottom: 1.5rem;
}

.control-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #495057;
}

.control-group select,
.control-group input[type="number"] {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #dee2e6;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.control-group select:focus,
.control-group input[type="number"]:focus {
    outline: none;
    border-color: #667eea;
}

.control-group select:disabled {
    background: #e9ecef;
    cursor: not-allowed;
}

.checkbox-group label {
    display: flex;
    align-items: center;
    cursor: pointer;
}

.checkbox-group input[type="checkbox"] {
    margin-right: 0.5rem;
    width: 1.2rem;
    height: 1.2rem;
    cursor: pointer;
}

.btn-primary,
.btn-secondary {
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    width: 100%;
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.btn-primary:disabled {
    background: #dee2e6;
    cursor: not-allowed;
    transform: none;
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover:not(:disabled) {
    background: #5a6268;
}

.btn-secondary:disabled {
    background: #dee2e6;
    cursor: not-allowed;
}

.output-section {
    padding: 2rem;
}

.output-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.output-header h2 {
    color: #495057;
}

#output {
    background: #f8f9fa;
    border: 2px solid #dee2e6;
    border-radius: 8px;
    padding: 1.5rem;
    overflow-x: auto;
    max-height: 600px;
    overflow-y: auto;
}

#output code {
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
    font-size: 0.9rem;
    line-height: 1.6;
    color: #212529;
}

.stats-section {
    padding: 2rem;
    background: #f8f9fa;
    border-top: 1px solid #e9ecef;
}

.stats-section h3 {
    margin-bottom: 1rem;
    color: #495057;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.stat-item {
    background: white;
    padding: 1rem;
    border-radius: 8px;
    border: 2px solid #dee2e6;
}

.stat-label {
    display: block;
    font-size: 0.9rem;
    color: #6c757d;
    margin-bottom: 0.5rem;
}

.stat-value {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    color: #667eea;
}

@media (max-width: 768px) {
    body {
        padding: 1rem;
    }

    header h1 {
        font-size: 2rem;
    }

    .controls,
    .output-section,
    .stats-section {
        padding: 1.5rem;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }
}