:root {
    --primary-blue-1: #00D9FF;
    --primary-blue-2: #0096FF;
    --primary-blue-3: #0059FF;
    --primary-blue-4: #0019FF;
    --primary-purple: #5800FF;
    --background: #f8fafc;
    --surface: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, var(--primary-blue-1) 0%, var(--primary-blue-3) 100%);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    padding-bottom: 80px;
}

.app-header {
    background: var(--surface);
    padding: 1rem;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
}

.app-header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-blue-3);
}

.user-stats {
    display: flex;
    gap: 1rem;
    font-size: 0.875rem;
    font-weight: 600;
}

.user-stats span {
    background: linear-gradient(45deg, var(--primary-blue-2), var(--primary-blue-3));
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
}

.app-main {
    padding: 1rem;
    max-width: 1200px;
    margin: 0 auto;
}

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

.section.active {
    display: block;
}

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

/* Home Section */
.welcome-card {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
    text-align: center;
}

.welcome-card h2 {
    color: var(--primary-blue-3);
    margin-bottom: 0.5rem;
    font-size: 1.5rem;
}

.welcome-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.daily-challenge {
    background: linear-gradient(135deg, var(--primary-blue-1), var(--primary-blue-2));
    border-radius: var(--border-radius);
    padding: 1.5rem;
    color: white;
}

.daily-challenge h3 {
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.progress-bar {
    background: rgba(255, 255, 255, 0.3);
    border-radius: 10px;
    height: 8px;
    margin: 1rem 0;
    overflow: hidden;
}

.progress-fill {
    background: white;
    height: 100%;
    border-radius: 10px;
    transition: width 0.3s ease;
    width: 0%;
}

#daily-progress-text {
    font-size: 0.875rem;
    opacity: 0.9;
}

.exercise-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1rem;
}

.exercise-card {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
    cursor: pointer;
}

.exercise-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.exercise-card i {
    font-size: 2.5rem;
    color: var(--primary-blue-3);
    margin-bottom: 1rem;
}

.exercise-card h3 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: 1.2rem;
}

.exercise-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
}

.start-btn, .btn-primary, .btn-secondary {
    background: linear-gradient(45deg, var(--primary-blue-2), var(--primary-blue-3));
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-block;
    font-size: 0.9rem;
}

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

.btn-secondary {
    background: linear-gradient(45deg, var(--text-secondary), var(--text-primary));
}

/* Exercise Section */
.exercise-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    background: var(--surface);
    padding: 1rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.back-btn {
    background: none;
    border: none;
    color: var(--primary-blue-3);
    font-size: 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem;
    border-radius: 8px;
    transition: var(--transition);
}

.back-btn:hover {
    background: rgba(0, 89, 255, 0.1);
}

.exercise-stats {
    display: flex;
    gap: 0.5rem;
    font-size: 0.875rem;
    font-weight: 600;
}

.exercise-stats span {
    background: var(--primary-blue-1);
    color: var(--primary-blue-4);
    padding: 0.25rem 0.75rem;
    border-radius: 15px;
}

.exercise-content {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
}

.instructions {
    background: linear-gradient(135deg, var(--primary-blue-1), var(--primary-blue-2));
    color: white;
    padding: 1rem;
    border-radius: var(--border-radius);
    margin-bottom: 2rem;
    text-align: center;
}

.exercise-area {
    min-height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 2rem;
    border: 2px dashed var(--primary-blue-1);
    border-radius: var(--border-radius);
    padding: 2rem;
}

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

.feedback {
    text-align: center;
    padding: 1rem;
    border-radius: var(--border-radius);
    margin-top: 1rem;
    display: none;
}

.feedback.success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success);
    border: 1px solid var(--success);
    display: block;
}

.feedback.error {
    background: rgba(239, 68, 68, 0.1);
    color: var(--error);
    border: 1px solid var(--error);
    display: block;
}

/* Exercise Specific Styles */
.sequence-display {
    font-size: 2rem;
    font-weight: bold;
    color: var(--primary-blue-3);
    text-align: center;
    padding: 2rem;
    background: var(--background);
    border-radius: var(--border-radius);
    margin: 1rem 0;
}

.word-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin: 1rem 0;
}

.word-item {
    background: var(--primary-blue-1);
    color: var(--primary-blue-4);
    padding: 1rem;
    border-radius: var(--border-radius);
    text-align: center;
    font-weight: 600;
    font-size: 1.1rem;
}

.color-sequence {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    flex-wrap: wrap;
    margin: 1rem 0;
}

.color-item {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    border: 3px solid white;
    box-shadow: var(--shadow);
    cursor: pointer;
    transition: var(--transition);
}

.color-item:hover {
    transform: scale(1.1);
}

.spatial-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
    max-width: 300px;
    margin: 1rem auto;
}

.grid-cell {
    aspect-ratio: 1;
    background: var(--background);
    border: 2px solid var(--primary-blue-1);
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
}

.grid-cell.active {
    background: var(--primary-blue-2);
}

.grid-cell.selected {
    background: var(--primary-blue-3);
}

.answer-input {
    width: 100%;
    max-width: 400px;
    padding: 1rem;
    border: 2px solid var(--primary-blue-1);
    border-radius: var(--border-radius);
    font-size: 1.1rem;
    text-align: center;
    margin: 1rem auto;
    display: block;
}

.answer-input:focus {
    outline: none;
    border-color: var(--primary-blue-3);
    box-shadow: 0 0 0 3px rgba(0, 89, 255, 0.1);
}

/* Progress Section */
.stats-overview {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-card i {
    font-size: 2rem;
    color: var(--primary-blue-3);
}

.stat-info {
    display: flex;
    flex-direction: column;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-blue-3);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.progress-charts {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.chart-container {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
}

.chart-container h3 {
    margin-bottom: 1rem;
    color: var(--primary-blue-3);
}

.chart {
    height: 200px;
    display: flex;
    align-items: end;
    gap: 0.5rem;
    padding: 1rem 0;
}

.chart-bar {
    flex: 1;
    background: linear-gradient(to top, var(--primary-blue-2), var(--primary-blue-1));
    border-radius: 4px 4px 0 0;
    min-height: 20px;
    position: relative;
    transition: var(--transition);
}

.chart-bar:hover {
    transform: scaleY(1.05);
}

.chart-label {
    position: absolute;
    bottom: -25px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-align: center;
}

.achievements {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
}

.achievements h3 {
    margin-bottom: 1rem;
    color: var(--primary-blue-3);
}

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

.achievement-card {
    background: var(--background);
    border-radius: var(--border-radius);
    padding: 1rem;
    text-align: center;
    transition: var(--transition);
}

.achievement-card.unlocked {
    background: linear-gradient(135deg, var(--primary-blue-1), var(--primary-blue-2));
    color: white;
    transform: scale(1.02);
}

.achievement-card i {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    color: var(--primary-blue-3);
}

.achievement-card.unlocked i {
    color: white;
}

/* Learn Section */
.learning-modules {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.module-card {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
}

.module-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.module-card i {
    font-size: 3rem;
    color: var(--primary-blue-3);
    margin-bottom: 1rem;
}

.module-card h3 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    font-size: 1.3rem;
}

.module-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.module-btn {
    background: linear-gradient(45deg, var(--primary-blue-2), var(--primary-blue-3));
    color: white;
    border: none;
    padding: 0.75rem 2rem;
    border-radius: 25px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

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

.module-content {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
}

.module-content h3 {
    color: var(--primary-blue-3);
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.module-content h4 {
    color: var(--primary-blue-2);
    margin: 1.5rem 0 0.5rem 0;
    font-size: 1.2rem;
}

.module-content p {
    margin-bottom: 1rem;
    line-height: 1.7;
}

.module-content ul {
    margin: 1rem 0;
    padding-left: 2rem;
}

.module-content li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.tip-box {
    background: linear-gradient(135deg, var(--primary-blue-1), var(--primary-blue-2));
    color: white;
    padding: 1rem;
    border-radius: var(--border-radius);
    margin: 1rem 0;
}

.tip-box strong {
    display: block;
    margin-bottom: 0.5rem;
}

/* FAQ Section */
.faq-container {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--surface);
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
    box-shadow: var(--shadow);
    overflow: hidden;
}

.faq-question {
    width: 100%;
    background: none;
    border: none;
    padding: 1.5rem;
    text-align: left;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

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

.faq-question[aria-expanded="true"] {
    background: linear-gradient(135deg, var(--primary-blue-1), var(--primary-blue-2));
    color: white;
}

.faq-icon {
    font-size: 1.5rem;
    font-weight: bold;
    transition: transform 0.3s ease;
}

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

.faq-answer {
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
}

.faq-answer:not([hidden]) {
    padding: 1.5rem;
    max-height: 200px;
}

.faq-answer p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Bottom Navigation */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--surface);
    display: flex;
    justify-content: space-around;
    padding: 0.75rem 0;
    box-shadow: 0 -4px 6px -1px rgba(0, 0, 0, 0.1);
    z-index: 1000;
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.75rem;
    font-weight: 500;
    padding: 0.5rem;
    border-radius: 8px;
    transition: var(--transition);
    min-width: 60px;
}

.nav-item i {
    font-size: 1.25rem;
    margin-bottom: 0.25rem;
}

.nav-item.active {
    color: var(--primary-blue-3);
    background: rgba(0, 89, 255, 0.1);
}

.nav-item:hover {
    color: var(--primary-blue-3);
    background: rgba(0, 89, 255, 0.05);
}

/* Footer */
footer {
    background: var(--text-primary);
    color: white;
    text-align: center;
    padding: 1rem;
    font-size: 0.875rem;
    margin-top: 2rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .app-header {
        padding: 0.75rem;
    }
    
    .app-header h1 {
        font-size: 1.25rem;
    }
    
    .user-stats {
        gap: 0.5rem;
        font-size: 0.75rem;
    }
    
    .app-main {
        padding: 0.75rem;
    }
    
    .welcome-card {
        padding: 1.5rem;
    }
    
    .exercise-grid {
        grid-template-columns: 1fr;
    }
    
    .exercise-card {
        padding: 1.25rem;
    }
    
    .stats-overview {
        grid-template-columns: 1fr;
    }
    
    .progress-charts {
        grid-template-columns: 1fr;
    }
    
    .learning-modules {
        grid-template-columns: 1fr;
    }
    
    .exercise-header {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .exercise-controls {
        flex-direction: column;
        align-items: center;
    }
    
    .color-sequence {
        justify-content: center;
    }
    
    .color-item {
        width: 50px;
        height: 50px;
    }
    
    .spatial-grid {
        max-width: 250px;
    }
}

@media (max-width: 480px) {
    .app-header h1 {
        font-size: 1.1rem;
    }
    
    .user-stats span {
        padding: 0.2rem 0.5rem;
        font-size: 0.7rem;
    }
    
    .welcome-card h2 {
        font-size: 1.25rem;
    }
    
    .exercise-card h3 {
        font-size: 1.1rem;
    }
    
    .bottom-nav {
        padding: 0.5rem 0;
    }
    
    .nav-item {
        font-size: 0.7rem;
        min-width: 50px;
    }
    
    .nav-item i {
        font-size: 1.1rem;
    }
}

/* Animations */
@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.pulse {
    animation: pulse 2s infinite;
}

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

.slide-in {
    animation: slideIn 0.3s ease-out;
}

@keyframes bounce {
    0%, 20%, 53%, 80%, 100% { transform: translate3d(0,0,0); }
    40%, 43% { transform: translate3d(0, -8px, 0); }
    70% { transform: translate3d(0, -4px, 0); }
    90% { transform: translate3d(0, -2px, 0); }
}

.bounce {
    animation: bounce 1s ease-in-out;
}

/* Loading States */
.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); }
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.hidden { display: none !important; }
.visible { display: block !important; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.p-1 { padding: 0.5rem; }
.p-2 { padding: 1rem; }