:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --light-color: #ecf0f1;
    --danger-color: #e74c3c;
    --success-color: #2ecc71;
    --warning-color: #f39c12;
    --dark-text: #2c3e50;
    --light-text: #7f8c8d;
    --border-color: #bdc3c7;
    --shadow: 0 2px 10px rgba(0,0,0,0.1);
    --border-radius: 12px;
    --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(--light-color) 0%, #d5dbdb 100%);
    background-attachment: fixed;
    color: var(--dark-text);
    line-height: 1.6;
    padding-bottom: 80px;
    min-height: 100vh;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(circle at 25% 25%, rgba(46, 204, 113, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 75% 75%, rgba(52, 152, 219, 0.1) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}

.app-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, #34495e 100%);
    color: white;
    padding: 1rem;
    text-align: center;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow);
}

.app-header h1 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.user-score {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-weight: bold;
    font-size: 1.1rem;
}

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

.content-section {
    display: none;
    animation: fadeIn 0.3s ease-in-out;
}

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

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

.scanner-container {
    background: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    margin-bottom: 1rem;
}

.scanner-container h2 {
    text-align: center;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
}

.camera-container {
    position: relative;
    width: 100%;
    max-width: 400px;
    margin: 0 auto 1rem;
    border-radius: var(--border-radius);
    overflow: hidden;
    background: #000;
}

#camera-preview {
    width: 100%;
    height: 300px;
    object-fit: cover;
}

.scanner-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.scanner-frame {
    width: 200px;
    height: 100px;
    border: 2px solid var(--success-color);
    border-radius: 8px;
    position: relative;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 0.7; }
    50% { opacity: 1; }
}

.scanner-controls {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.manual-input {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
}

.manual-input input {
    flex: 1;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    text-align: center;
    justify-content: center;
    min-width: 120px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--secondary-color) 0%, #2980b9 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
}

.btn-secondary {
    background: linear-gradient(135deg, #95a5a6 0%, #7f8c8d 100%);
    color: white;
}

.btn-success {
    background: linear-gradient(135deg, var(--success-color) 0%, #27ae60 100%);
    color: white;
}

.btn-danger {
    background: linear-gradient(135deg, var(--danger-color) 0%, #c0392b 100%);
    color: white;
}

.btn-outline {
    background: white;
    border: 2px solid var(--secondary-color);
    color: var(--secondary-color);
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.scan-result {
    background: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    margin-top: 1rem;
}

.product-info h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

.product-details {
    display: grid;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.environmental-impact {
    margin-bottom: 1.5rem;
}

.environmental-impact h4 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.impact-score {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.score-circle {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--success-color) 0%, #27ae60 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 1.5rem;
}

.score-circle.low {
    background: linear-gradient(135deg, var(--danger-color) 0%, #c0392b 100%);
}

.score-circle.medium {
    background: linear-gradient(135deg, var(--warning-color) 0%, #e67e22 100%);
}

.score-description {
    flex: 1;
}

.score-description span {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
}

.impact-details {
    display: grid;
    gap: 0.5rem;
}

.impact-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem;
    background: var(--light-color);
    border-radius: 8px;
}

.impact-item i {
    color: var(--secondary-color);
    width: 20px;
}

.certifications, .alternatives {
    margin-bottom: 1.5rem;
}

.certifications h4, .alternatives h4 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.certifications-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.certification-badge {
    background: var(--success-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.alternatives-list {
    display: grid;
    gap: 1rem;
}

.alternative-item {
    padding: 1rem;
    background: var(--light-color);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--success-color);
}

.alternative-item h5 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.alternative-score {
    display: inline-block;
    background: var(--success-color);
    color: white;
    padding: 0.25rem 0.5rem;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: bold;
    margin-top: 0.5rem;
}

.history-filters {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 0.5rem 1rem;
    border: 2px solid var(--border-color);
    background: white;
    color: var(--dark-text);
    border-radius: 20px;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

.filter-btn.active {
    background: var(--secondary-color);
    color: white;
    border-color: var(--secondary-color);
}

.history-list {
    display: grid;
    gap: 1rem;
}

.history-item {
    background: white;
    border-radius: var(--border-radius);
    padding: 1rem;
    box-shadow: var(--shadow);
    cursor: pointer;
    transition: var(--transition);
}

.history-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0,0,0,0.15);
}

.history-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.history-item h4 {
    color: var(--primary-color);
    font-size: 1.1rem;
}

.history-date {
    color: var(--light-text);
    font-size: 0.9rem;
}

.history-score {
    display: inline-block;
    background: var(--success-color);
    color: white;
    padding: 0.25rem 0.5rem;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: bold;
}

.profile-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    text-align: center;
    box-shadow: var(--shadow);
}

.stat-number {
    font-size: 2rem;
    font-weight: bold;
    color: var(--secondary-color);
    margin-bottom: 0.5rem;
}

.stat-label {
    color: var(--light-text);
    font-size: 0.9rem;
}

.achievements, .sustainability-tips {
    background: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    margin-bottom: 1rem;
}

.achievements h3, .sustainability-tips h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.achievements-list {
    display: grid;
    gap: 0.5rem;
}

.achievement-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.75rem;
    background: var(--light-color);
    border-radius: 8px;
}

.achievement-item.unlocked {
    background: linear-gradient(135deg, #fff3cd 0%, #ffeaa7 100%);
    border-left: 4px solid var(--warning-color);
}

.achievement-icon {
    font-size: 1.5rem;
}

.achievement-info h5 {
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

.achievement-info p {
    color: var(--light-text);
    font-size: 0.9rem;
}

.tips-list {
    display: grid;
    gap: 1rem;
}

.tip-item {
    padding: 1rem;
    background: var(--light-color);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--success-color);
}

.tip-item h5 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.settings-group {
    background: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    margin-bottom: 1rem;
}

.settings-group h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.setting-item {
    margin-bottom: 1rem;
}

.setting-item:last-child {
    margin-bottom: 0;
}

.setting-item label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-weight: 500;
}

.setting-item input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.setting-item input[type="range"] {
    flex: 1;
    margin: 0 0.5rem;
}

.setting-item select {
    padding: 0.5rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    width: 100%;
    margin-top: 0.5rem;
}

.faq-section {
    background: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    margin: 2rem 0;
}

.faq-section h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
}

.faq-container {
    display: grid;
    gap: 1rem;
}

.faq-item {
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    overflow: hidden;
}

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

.faq-question:hover {
    background: var(--light-color);
}

.faq-question[aria-expanded="true"] {
    background: var(--secondary-color);
    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: 1rem;
    background: var(--light-color);
    border-top: 1px solid var(--border-color);
    animation: slideDown 0.3s ease-out;
}

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

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

.no-data {
    text-align: center;
    padding: 2rem;
    color: var(--light-text);
}

.no-data i {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--border-color);
}

.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: white;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-around;
    padding: 0.5rem 0;
    z-index: 100;
    box-shadow: 0 -2px 10px rgba(0,0,0,0.1);
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 0.5rem;
    color: var(--light-text);
    text-decoration: none;
    transition: var(--transition);
    border-radius: 8px;
    min-width: 60px;
}

.nav-item i {
    font-size: 1.2rem;
    margin-bottom: 0.25rem;
}

.nav-item span {
    font-size: 0.7rem;
    font-weight: 500;
}

.nav-item.active {
    color: var(--secondary-color);
    background: rgba(52, 152, 219, 0.1);
}

footer {
    background: var(--primary-color);
    color: white;
    text-align: center;
    padding: 1rem;
    margin-top: 2rem;
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .main-content {
        padding: 0.5rem;
    }
    
    .scanner-controls {
        flex-direction: column;
    }
    
    .manual-input {
        flex-direction: column;
    }
    
    .profile-stats {
        grid-template-columns: 1fr;
    }
    
    .history-filters {
        justify-content: center;
    }
    
    .btn {
        min-width: 100px;
        padding: 0.6rem 1rem;
        font-size: 0.9rem;
    }
}

@media (max-width: 480px) {
    .app-header h1 {
        font-size: 1.3rem;
    }
    
    .user-score {
        font-size: 1rem;
    }
    
    .scanner-container, .settings-group, .faq-section {
        padding: 1rem;
    }
    
    .stat-number {
        font-size: 1.5rem;
    }
    
    .nav-item span {
        font-size: 0.6rem;
    }
}

.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255,255,255,.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
}

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

.toast {
    position: fixed;
    top: 20px;
    right: 20px;
    background: var(--primary-color);
    color: white;
    padding: 1rem 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    z-index: 1000;
    animation: slideInRight 0.3s ease-out;
}

.toast.success {
    background: var(--success-color);
}

.toast.error {
    background: var(--danger-color);
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}