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

:root {
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --success-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --dark-bg: #0f0c29;
    --dark-secondary: #1a1640;
    --card-bg: rgba(255, 255, 255, 0.05);
    --text-primary: #ffffff;
    --text-secondary: #b8b8d4;
    --border-color: rgba(255, 255, 255, 0.1);
    --shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.37);
    --glow: 0 0 20px rgba(102, 126, 234, 0.4);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #0f0c29, #302b63, #24243e);
    min-height: 100vh;
    color: var(--text-primary);
    padding: 20px;
    overflow-x: hidden;
}

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

/* Header */
.header {
    text-align: center;
    margin-bottom: 50px;
    animation: fadeInDown 0.8s ease;
}

.header h1 {
    font-size: 3rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
    font-weight: 700;
    text-shadow: 0 0 30px rgba(102, 126, 234, 0.5);
}

.header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Main Card */
.main-card {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-radius: 20px;
    border: 1px solid var(--border-color);
    padding: 40px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
    animation: fadeInUp 0.8s ease;
}

/* Form Styles */
.form-section {
    margin-bottom: 30px;
}

.form-section h2 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 10px;
}

.form-section h2::before {
    content: '';
    width: 4px;
    height: 24px;
    background: var(--primary-gradient);
    border-radius: 2px;
}

.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 10px;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
}

.form-control {
    width: 100%;
    padding: 15px 20px;
    background: rgba(255, 255, 255, 0.05);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    color: var(--text-primary);
    font-size: 1rem;
    transition: all 0.3s ease;
    outline: none;
}

.form-control:focus {
    border-color: #667eea;
    box-shadow: var(--glow);
    background: rgba(255, 255, 255, 0.08);
}

.form-control option {
    background: var(--dark-secondary);
    color: var(--text-primary);
}

.btn {
    padding: 15px 40px;
    background: var(--primary-gradient);
    border: none;
    border-radius: 12px;
    color: white;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
}

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

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* Results Section */
.results-section {
    display: none;
    animation: fadeInUp 0.6s ease;
}

.results-section.active {
    display: block;
}

.vehicle-info {
    background: rgba(102, 126, 234, 0.1);
    border-left: 4px solid #667eea;
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 30px;
}

.vehicle-info h3 {
    font-size: 1.3rem;
    margin-bottom: 10px;
}

.vehicle-info p {
    color: var(--text-secondary);
    margin: 5px 0;
}

.vehicle-info .engine-types {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 10px;
}

.engine-tag {
    background: rgba(102, 126, 234, 0.2);
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    color: #a8b5ff;
}

/* Oil Cards */
.oil-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 25px;
    margin-top: 20px;
}

.oil-card {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 25px;
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.oil-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--success-gradient);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.oil-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px rgba(102, 126, 234, 0.3);
    border-color: #667eea;
}

.oil-card:hover::before {
    transform: scaleX(1);
}

.oil-card h4 {
    font-size: 1.3rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.oil-specs {
    display: flex;
    gap: 15px;
    margin-bottom: 15px;
}

.spec-badge {
    background: rgba(79, 172, 254, 0.2);
    padding: 8px 15px;
    border-radius: 8px;
    font-size: 0.9rem;
    color: #4facfe;
    font-weight: 600;
}

.oil-features {
    margin-top: 15px;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 8px 0;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.feature-item::before {
    content: '✓';
    color: #00f2fe;
    font-weight: bold;
    font-size: 1.2rem;
}

/* Loading Spinner */
.loading {
    display: none;
    text-align: center;
    padding: 20px;
}

.loading.active {
    display: block;
}

.spinner {
    border: 4px solid rgba(255, 255, 255, 0.1);
    border-top: 4px solid #667eea;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 0 auto;
}

/* Animations */
@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Responsive */
@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }
    
    .main-card {
        padding: 25px;
    }
    
    .oil-grid {
        grid-template-columns: 1fr;
    }
    
    .oil-specs {
        flex-direction: column;
        gap: 10px;
    }
}

/* Info Box */
.info-box {
    background: rgba(79, 172, 254, 0.1);
    border-left: 4px solid #4facfe;
    padding: 15px 20px;
    border-radius: 8px;
    margin: 20px 0;
    color: var(--text-secondary);
}

.info-box strong {
    color: var(--text-primary);
}