:root {
    --primary-blue: #2196F3;
    --success-green: #4CAF50;
    --warning-amber: #FFC107;
    --error-red: #F44336;
    --accent-purple: #9C27B0;
    --background: #f5f5f5;
    --surface: #ffffff;
    --text-primary: #212121;
    --text-secondary: #757575;
    --shadow: 0 2px 8px rgba(0,0,0,0.1);
    --border-radius: 8px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--background) 0%, #e8f4fd 100%);
    background-attachment: fixed;
    color: var(--text-primary);
    line-height: 1.6;
    padding-bottom: 80px;
    min-height: 100vh;
    position: relative;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        radial-gradient(circle at 25% 25%, rgba(33, 150, 243, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 75% 75%, rgba(76, 175, 80, 0.05) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}

header {
    background: linear-gradient(135deg, var(--primary-blue), #1976D2);
    color: white;
    padding: var(--spacing-lg) var(--spacing-md);
    text-align: center;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

header h1 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0;
}

header h1 i {
    margin-right: var(--spacing-sm);
    color: var(--warning-amber);
}

main {
    padding: var(--spacing-md);
    max-width: 1200px;
    margin: 0 auto;
}

.page-section {
    display: none;
    background: var(--surface);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    position: relative;
    overflow: hidden;
}

.page-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-blue), var(--success-green), var(--warning-amber));
}

.page-section.active {
    display: block;
    animation: fadeInUp 0.4s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.page-section h2 {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-lg);
    font-size: 1.4rem;
    border-bottom: 2px solid var(--primary-blue);
    padding-bottom: var(--spacing-sm);
}

.search-container, .arrivals-container, .alerts-container, 
.fare-container, .accessibility-container {
    margin-bottom: var(--spacing-lg);
}

.search-form, .fare-form {
    display: grid;
    gap: var(--spacing-md);
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.input-group label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.input-group input, .input-group select {
    padding: 12px var(--spacing-md);
    border: 2px solid #e0e0e0;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    background: var(--surface);
}

.input-group input:focus, .input-group select:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.1);
}

.search-btn, .action-btn, .calculate-btn, .pay-btn {
    background: linear-gradient(135deg, var(--primary-blue), #1976D2);
    color: white;
    border: none;
    padding: 12px var(--spacing-lg);
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.search-btn:hover, .action-btn:hover, .calculate-btn:hover, .pay-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.3);
}

.search-btn:active, .action-btn:active, .calculate-btn:active, .pay-btn:active {
    transform: translateY(0);
}

.routes-container, .nearby-container {
    margin-top: var(--spacing-lg);
}

.routes-container h3, .nearby-container h3 {
    color: var(--success-green);
    margin-bottom: var(--spacing-md);
    font-size: 1.2rem;
}

.route-item, .stop-item, .arrival-item, .alert-item, .accessible-stop-item {
    background: #f8f9fa;
    border: 1px solid #e9ecef;
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    transition: var(--transition);
    position: relative;
}

.route-item:hover, .stop-item:hover, .arrival-item:hover, 
.alert-item:hover, .accessible-stop-item:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow);
}

.route-item h4 {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-sm);
}

.route-duration {
    color: var(--success-green);
    font-weight: 600;
    font-size: 1.1rem;
}

.route-steps {
    margin-top: var(--spacing-sm);
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.stop-selector {
    margin-bottom: var(--spacing-md);
}

.stop-selector label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

.stop-selector select {
    width: 100%;
    padding: 10px;
    border: 2px solid #e0e0e0;
    border-radius: var(--border-radius);
    background: var(--surface);
}

.arrival-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.arrival-line {
    font-weight: 600;
    color: var(--primary-blue);
}

.arrival-time {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--success-green);
}

.arrival-time.delayed {
    color: var(--error-red);
}

.alert-filters {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
}

.filter-btn {
    padding: 8px var(--spacing-md);
    border: 2px solid var(--primary-blue);
    background: transparent;
    color: var(--primary-blue);
    border-radius: 20px;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

.filter-btn.active, .filter-btn:hover {
    background: var(--primary-blue);
    color: white;
}

.alert-item {
    border-left: 4px solid var(--warning-amber);
}

.alert-item.disruption {
    border-left-color: var(--error-red);
}

.alert-item.delay {
    border-left-color: var(--warning-amber);
}

.alert-item.maintenance {
    border-left-color: var(--primary-blue);
}

.alert-title {
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.alert-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.alert-time {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: var(--spacing-sm);
}

.fare-result {
    background: #e8f5e8;
    border: 2px solid var(--success-green);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    margin-top: var(--spacing-md);
}

.fare-result h3 {
    color: var(--success-green);
    margin-bottom: var(--spacing-md);
}

.fare-details {
    margin-bottom: var(--spacing-md);
}

.fare-amount {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--success-green);
    margin: var(--spacing-sm) 0;
}

.pay-btn {
    background: linear-gradient(135deg, var(--success-green), #388E3C);
}

.accessibility-filters h3 {
    color: var(--accent-purple);
    margin-bottom: var(--spacing-md);
}

.filter-options {
    display: grid;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
    padding: var(--spacing-sm);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.checkbox-label:hover {
    background: #f0f0f0;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--accent-purple);
}

.accessible-stop-item {
    border-left: 4px solid var(--accent-purple);
}

.accessibility-features {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-sm);
    flex-wrap: wrap;
}

.feature-badge {
    background: var(--accent-purple);
    color: white;
    padding: 4px var(--spacing-sm);
    border-radius: 12px;
    font-size: 0.8rem;
}

.faq-section {
    background: var(--surface);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

.faq-section h2 {
    color: var(--accent-purple);
    margin-bottom: var(--spacing-lg);
    font-size: 1.4rem;
    border-bottom: 2px solid var(--accent-purple);
    padding-bottom: var(--spacing-sm);
}

.faq-container {
    display: grid;
    gap: var(--spacing-sm);
}

.faq-item {
    border: 1px solid #e0e0e0;
    border-radius: var(--border-radius);
    overflow: hidden;
}

.faq-question {
    width: 100%;
    background: #f8f9fa;
    border: none;
    padding: var(--spacing-md);
    text-align: left;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

.faq-question:hover {
    background: #e9ecef;
}

.faq-question[aria-expanded="true"] {
    background: var(--accent-purple);
    color: white;
}

.faq-question[aria-expanded="true"] .faq-icon {
    transform: rotate(45deg);
}

.faq-icon {
    font-size: 1.2rem;
    font-weight: bold;
    transition: var(--transition);
}

.faq-answer {
    padding: var(--spacing-md);
    background: var(--surface);
    border-top: 1px solid #e0e0e0;
    animation: fadeIn 0.3s ease-out;
}

.faq-answer[hidden] {
    display: none;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--surface);
    border-top: 1px solid #e0e0e0;
    display: flex;
    justify-content: space-around;
    padding: var(--spacing-sm) 0;
    box-shadow: 0 -2px 8px rgba(0,0,0,0.1);
    z-index: 1000;
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    text-decoration: none;
    color: var(--text-secondary);
    padding: var(--spacing-sm);
    border-radius: var(--border-radius);
    transition: var(--transition);
    min-width: 60px;
}

.nav-item:hover {
    background: #f0f0f0;
}

.nav-item.active {
    color: var(--primary-blue);
    background: rgba(33, 150, 243, 0.1);
}

.nav-item i {
    font-size: 1.2rem;
}

.nav-item span {
    font-size: 0.7rem;
    font-weight: 600;
}

footer {
    background: var(--text-primary);
    color: var(--surface);
    text-align: center;
    padding: var(--spacing-md);
    font-size: 0.9rem;
    margin-top: var(--spacing-lg);
}

.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-lg);
    color: var(--text-secondary);
}

.loading::before {
    content: '';
    width: 20px;
    height: 20px;
    border: 2px solid #e0e0e0;
    border-top: 2px solid var(--primary-blue);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.error-message {
    background: #ffebee;
    color: var(--error-red);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    border: 1px solid var(--error-red);
    margin: var(--spacing-md) 0;
}

.success-message {
    background: #e8f5e8;
    color: var(--success-green);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    border: 1px solid var(--success-green);
    margin: var(--spacing-md) 0;
}

@media (min-width: 768px) {
    .search-form, .fare-form {
        grid-template-columns: 1fr 1fr;
        align-items: end;
    }
    
    .search-btn, .calculate-btn {
        grid-column: 1 / -1;
    }
    
    .alert-filters {
        justify-content: flex-start;
    }
    
    .filter-options {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .bottom-nav {
        justify-content: center;
        gap: var(--spacing-lg);
    }
    
    .nav-item {
        min-width: 80px;
    }
    
    .nav-item span {
        font-size: 0.8rem;
    }
}

@media (min-width: 1024px) {
    main {
        padding: var(--spacing-lg);
    }
    
    .search-form, .fare-form {
        grid-template-columns: 1fr 1fr 1fr;
    }
    
    .filter-options {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .faq-container {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.2rem;
    }
    
    .page-section {
        margin: 0 -var(--spacing-md);
        border-radius: 0;
    }
    
    .nav-item span {
        font-size: 0.6rem;
    }
    
    .nav-item i {
        font-size: 1rem;
    }
}