/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2196F3;
    --secondary-color: #4CAF50;
    --accent-color: #FFC107;
    --danger-color: #F44336;
    --background-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --glass-bg: rgba(255, 255, 255, 0.1);
    --glass-border: rgba(255, 255, 255, 0.2);
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.8);
    --shadow-light: 0 4px 15px rgba(0, 0, 0, 0.2);
    --shadow-heavy: 0 8px 32px rgba(31, 38, 135, 0.37);
    --border-radius: 20px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--background-gradient);
    min-height: 100vh;
    color: var(--text-primary);
    padding-bottom: 80px;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Accessibility - Skip Link */
.skip-link {
    position: absolute;
    top: -40px;
    left: 6px;
    background: var(--primary-color);
    color: white;
    padding: 8px;
    text-decoration: none;
    border-radius: 4px;
    z-index: 10000;
    transition: var(--transition);
}

.skip-link:focus {
    top: 6px;
}

/* Screen Reader Only */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Focus Styles for Accessibility */
*:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

button:focus,
a:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
    box-shadow: 0 0 0 4px rgba(33, 150, 243, 0.3);
}

/* Header */
.app-header {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-light);
}

.app-header h1 {
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0;
}

.language-toggle .lang-btn {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: var(--transition);
    font-weight: 500;
}

.language-toggle .lang-btn:hover,
.language-toggle .lang-btn:focus {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: var(--shadow-light);
}

.language-toggle .lang-btn[aria-pressed="true"] {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

/* Main Content */
.main-content {
    padding: 1rem;
    max-width: 500px;
    margin: 0 auto;
}

.section {
    display: none;
    animation: fadeIn 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.section.active {
    display: block;
}

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

/* Game Container */
.game-container {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: var(--border-radius);
    padding: 2rem;
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-heavy);
    transition: var(--transition);
}

.game-container:hover {
    box-shadow: 0 12px 40px rgba(31, 38, 135, 0.45);
}

.game-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 2rem;
    gap: 1rem;
}

.score-display {
    background: var(--glass-bg);
    padding: 0.75rem 1rem;
    border-radius: 15px;
    color: var(--text-primary);
    font-weight: 600;
    text-align: center;
    flex: 1;
    font-size: 0.9rem;
    border: 1px solid var(--glass-border);
    transition: var(--transition);
}

.score-display:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

/* Sound Grid */
.sound-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin: 2rem 0;
}

.sound-btn {
    aspect-ratio: 1;
    border: none;
    border-radius: var(--border-radius);
    font-size: 2rem;
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    background: var(--btn-color, var(--primary-color));
    box-shadow: var(--shadow-light);
    min-height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.sound-btn:hover {
    transform: translateY(-5px) scale(1.02);
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.4);
}

.sound-btn:active {
    transform: translateY(-2px) scale(0.98);
}

.sound-btn:focus {
    outline: 3px solid rgba(255, 255, 255, 0.5);
    outline-offset: 2px;
}

.sound-btn.playing {
    animation: glow 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    transform: scale(1.1);
}

.sound-btn.disabled {
    opacity: 0.5;
    cursor: pointer;
    position: relative;
}

.sound-btn.disabled::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.1);
    border-radius: inherit;
    pointer-events: none;
    z-index: -1;
}

.sound-btn[data-game-active="true"] {
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% {
        box-shadow: var(--shadow-light);
    }
    50% {
        box-shadow: 0 0 20px rgba(76, 175, 80, 0.6), var(--shadow-light);
    }
    100% {
        box-shadow: var(--shadow-light);
    }
}

@keyframes glow {
    0% { 
        box-shadow: var(--shadow-light);
        transform: scale(1);
    }
    50% { 
        box-shadow: 0 0 30px rgba(255, 255, 255, 0.8), 0 0 60px rgba(255, 255, 255, 0.4);
        transform: scale(1.1);
    }
    100% { 
        box-shadow: var(--shadow-light);
        transform: scale(1);
    }
}

/* Game Controls */
.game-controls {
    display: flex;
    gap: 1rem;
    margin: 2rem 0;
}

.control-btn {
    flex: 1;
    padding: 1rem;
    border: none;
    border-radius: 15px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    background: var(--glass-bg);
    color: var(--text-primary);
    border: 1px solid var(--glass-border);
    min-height: 48px;
}

.control-btn:hover,
.control-btn:focus {
    transform: translateY(-2px);
    background: rgba(255, 255, 255, 0.3);
    box-shadow: var(--shadow-light);
}

.control-btn.primary {
    background: var(--secondary-color);
    border-color: var(--secondary-color);
}

.control-btn.primary:hover,
.control-btn.primary:focus {
    background: #45a049;
    box-shadow: 0 8px 25px rgba(76, 175, 80, 0.4);
}

.control-btn.danger {
    background: var(--danger-color);
    border-color: var(--danger-color);
}

.control-btn.danger:hover,
.control-btn.danger:focus {
    background: #da190b;
    box-shadow: 0 8px 25px rgba(244, 67, 54, 0.4);
}

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

.game-status {
    text-align: center;
    margin-top: 1rem;
}

#gameMessage {
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: 500;
    padding: 1rem;
    background: var(--glass-bg);
    border-radius: 10px;
    border: 1px solid var(--glass-border);
    transition: var(--transition);
}

/* Statistics Section */
.stats-container {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: var(--border-radius);
    padding: 2rem;
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-heavy);
}

.stats-container h2 {
    color: var(--text-primary);
    margin-bottom: 2rem;
    text-align: center;
    font-size: 1.8rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--glass-bg);
    padding: 1.5rem;
    border-radius: 15px;
    text-align: center;
    color: var(--text-primary);
    border: 1px solid var(--glass-border);
    transition: var(--transition);
}

.stat-card:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-3px);
    box-shadow: var(--shadow-light);
}

.stat-icon {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.stat-value {
    font-size: 1.8rem;
    font-weight: bold;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.stat-label {
    font-size: 0.9rem;
    opacity: 0.8;
    color: var(--text-secondary);
}

.progress-section {
    background: var(--glass-bg);
    padding: 1.5rem;
    border-radius: 15px;
    margin-bottom: 2rem;
    border: 1px solid var(--glass-border);
}

.progress-section h3 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    text-align: center;
}

.progress-bar {
    background: rgba(255, 255, 255, 0.2);
    height: 12px;
    border-radius: 6px;
    overflow: hidden;
    margin-bottom: 0.5rem;
    border: 1px solid var(--glass-border);
}

.progress-fill {
    background: linear-gradient(90deg, var(--secondary-color), #66bb6a);
    height: 100%;
    border-radius: 6px;
    transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    width: 0%;
    box-shadow: 0 2px 8px rgba(76, 175, 80, 0.3);
}

#dailyProgressText {
    color: var(--text-primary);
    text-align: center;
    font-size: 0.9rem;
    font-weight: 500;
}

.export-section {
    text-align: center;
}

/* Settings Section */
.settings-container {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: var(--border-radius);
    padding: 2rem;
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-heavy);
}

.settings-container h2 {
    color: var(--text-primary);
    margin-bottom: 2rem;
    text-align: center;
    font-size: 1.8rem;
}

.setting-group {
    background: var(--glass-bg);
    padding: 1.5rem;
    border-radius: 15px;
    margin-bottom: 1.5rem;
    border: 1px solid var(--glass-border);
    transition: var(--transition);
}

.setting-group:hover {
    background: rgba(255, 255, 255, 0.15);
}

.setting-group h3 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.setting-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1rem;
    color: var(--text-primary);
    gap: 1rem;
}

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

.setting-item label {
    font-weight: 500;
    min-width: 100px;
    color: var(--text-primary);
}

.setting-item input[type="range"] {
    flex: 1;
    margin: 0 1rem;
    accent-color: var(--primary-color);
    background: transparent;
    cursor: pointer;
}

.setting-item input[type="range"]::-webkit-slider-thumb {
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    transition: var(--transition);
}

.setting-item input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.setting-item select {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    padding: 0.5rem;
    border-radius: 8px;
    min-width: 120px;
    cursor: pointer;
    transition: var(--transition);
}

.setting-item select:hover,
.setting-item select:focus {
    background: rgba(255, 255, 255, 0.2);
    border-color: var(--primary-color);
}

.setting-item select option {
    background: #333;
    color: var(--text-primary);
}

/* FAQ Section */
.faq-container {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: var(--border-radius);
    padding: 2rem;
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-heavy);
}

.faq-container h2 {
    color: var(--text-primary);
    margin-bottom: 2rem;
    text-align: center;
    font-size: 1.8rem;
}

.faq-item {
    background: var(--glass-bg);
    border-radius: 15px;
    margin-bottom: 1rem;
    border: 1px solid var(--glass-border);
    overflow: hidden;
    transition: var(--transition);
}

.faq-item:hover {
    background: rgba(255, 255, 255, 0.15);
}

.faq-question {
    width: 100%;
    background: none;
    border: none;
    padding: 1.5rem;
    text-align: left;
    color: var(--text-primary);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

.faq-question:hover,
.faq-question:focus {
    background: rgba(255, 255, 255, 0.1);
}

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

.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 cubic-bezier(0.4, 0, 0.2, 1);
    opacity: 0;
}

.faq-answer:not([hidden]) {
    padding: 0 1.5rem 1.5rem;
    max-height: 200px;
    opacity: 1;
}

.faq-answer p {
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
}

/* Bottom Navigation */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-top: 1px solid var(--glass-border);
    display: flex;
    padding: 0.5rem 0;
    z-index: 1000;
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.1);
}

.nav-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 0.5rem;
    text-decoration: none;
    color: var(--text-secondary);
    transition: var(--transition);
    font-size: 0.8rem;
    border-radius: 8px;
    margin: 0 0.25rem;
}

.nav-item:hover,
.nav-item:focus,
.nav-item.active {
    color: var(--text-primary);
    transform: translateY(-2px);
    background: rgba(255, 255, 255, 0.1);
}

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

/* Footer */
footer {
    text-align: center;
    padding: 1rem;
    color: var(--text-secondary);
    font-size: 0.8rem;
    margin-top: 2rem;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

footer a:hover,
footer a:focus {
    color: var(--text-primary);
    text-decoration: underline;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 10000;
    color: var(--text-primary);
    transition: opacity 0.3s ease-out;
}

.loading-overlay[hidden],
.loading-overlay[style*="display: none"] {
    opacity: 0;
    pointer-events: none;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 1rem;
}

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

/* Responsive Design */
@media (max-width: 480px) {
    .main-content {
        padding: 0.5rem;
    }
    
    .game-container,
    .stats-container,
    .settings-container,
    .faq-container {
        padding: 1.5rem;
    }
    
    .game-info {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .score-display {
        font-size: 0.8rem;
        padding: 0.4rem 0.8rem;
    }
    
    .sound-btn {
        font-size: 1.5rem;
        min-height: 70px;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
    
    .setting-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
    
    .setting-item input[type="range"] {
        width: 100%;
        margin: 0;
    }
    
    .control-btn {
        padding: 0.75rem;
        font-size: 0.9rem;
    }
    
    .app-header h1 {
        font-size: 1.2rem;
    }
    
    .language-toggle .lang-btn {
        padding: 0.4rem 0.8rem;
        font-size: 0.8rem;
    }
}

@media (min-width: 768px) {
    .main-content {
        max-width: 600px;
    }
    
    .sound-grid {
        gap: 1.5rem;
    }
    
    .sound-btn {
        font-size: 2.5rem;
        min-height: 100px;
    }
    
    .stats-grid {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .game-controls {
        gap: 1.5rem;
    }
    
    .control-btn {
        padding: 1.25rem;
        font-size: 1.1rem;
    }
}

@media (min-width: 1024px) {
    .main-content {
        max-width: 700px;
    }
    
    .sound-btn {
        min-height: 120px;
    }
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
    :root {
        --glass-bg: rgba(255, 255, 255, 0.2);
        --glass-border: rgba(255, 255, 255, 0.4);
    }
    
    .sound-btn {
        border: 2px solid var(--text-primary);
    }
    
    .control-btn {
        border: 2px solid var(--text-primary);
    }
}

/* Reduced Motion Support */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .sound-btn.playing {
        animation: none;
    }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --background-gradient: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    }
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.disabled {
    opacity: 0.5;
    pointer-events: none;
}

/* Color Variables */
.sound-btn[data-sound="0"] {
    background: var(--primary-color);
}

.sound-btn[data-sound="1"] {
    background: var(--secondary-color);
}

.sound-btn[data-sound="2"] {
    background: var(--accent-color);
}

.sound-btn[data-sound="3"] {
    background: var(--danger-color);
}

/* Focus Visible for better accessibility */
.sound-btn:focus-visible,
.control-btn:focus-visible,
.nav-item:focus-visible {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
    box-shadow: 0 0 0 4px rgba(33, 150, 243, 0.3);
}

/* Print Styles */
@media print {
    .bottom-nav,
    .game-controls,
    .loading-overlay {
        display: none !important;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .game-container,
    .stats-container,
    .settings-container,
    .faq-container {
        background: white;
        border: 1px solid #ccc;
        box-shadow: none;
    }
}