:root {
    --primary: #FF006E;
    --secondary: #FB5607;
    --accent: #FFBE0B;
    --purple: #8338EC;
    --blue: #3A86FF;
    --white: #FFFFFF;
    --gray-100: #F8F9FA;
    --gray-200: #E9ECEF;
    --gray-300: #DEE2E6;
    --gray-400: #CED4DA;
    --gray-500: #ADB5BD;
    --gray-600: #6C757D;
    --gray-700: #495057;
    --gray-800: #343A40;
    --gray-900: #212529;
    --black: #000000;
    --success: #28A745;
    --danger: #DC3545;
    --warning: #FFC107;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.15);
    --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: 'Arial', sans-serif;
    background: linear-gradient(135deg, var(--gray-100) 0%, var(--white) 100%);
    color: var(--gray-800);
    line-height: 1.6;
    overflow-x: hidden;
    padding-bottom: 80px;
}

header {
    background: linear-gradient(135deg, var(--primary) 0%, var(--purple) 100%);
    color: var(--white);
    padding: 1rem;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
}

.header-content h1 {
    font-size: 1.5rem;
    font-weight: bold;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.language-toggle {
    display: flex;
    gap: 0.5rem;
}

.lang-btn {
    background: rgba(255, 255, 255, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: var(--white);
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

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

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

.section {
    display: none;
    animation: fadeIn 0.5s ease-in-out;
}

.section.active {
    display: block;
}

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

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

.welcome-card h2 {
    color: var(--primary);
    font-size: 2rem;
    margin-bottom: 1rem;
}

.welcome-card p {
    color: var(--gray-600);
    font-size: 1.1rem;
    margin-bottom: 2rem;
    line-height: 1.8;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: linear-gradient(135deg, var(--blue) 0%, var(--purple) 100%);
    color: var(--white);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    gap: 1rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

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

.stat-card i {
    font-size: 1.5rem;
    opacity: 0.9;
}

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

.stat-number {
    font-size: 1.5rem;
    font-weight: bold;
}

.stat-label {
    font-size: 0.8rem;
    opacity: 0.9;
}

.game-modes {
    display: grid;
    gap: 1rem;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.mode-btn {
    background: var(--white);
    border: 2px solid var(--gray-200);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    position: relative;
    overflow: hidden;
}

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

.mode-btn i {
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.mode-btn span {
    font-size: 1.2rem;
    font-weight: bold;
    color: var(--gray-800);
}

.mode-btn small {
    color: var(--gray-600);
    font-size: 0.9rem;
}

.game-container {
    max-width: 800px;
    margin: 0 auto;
}

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

.progress-bar {
    height: 8px;
    background: var(--gray-200);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 1rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--secondary) 0%, var(--primary) 100%);
    transition: width 0.3s ease;
    width: 0%;
}

.game-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: bold;
    color: var(--gray-700);
}

.score-display {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--accent);
}

.challenge-card {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    margin-bottom: 1rem;
}

.challenge-type {
    background: linear-gradient(135deg, var(--secondary) 0%, var(--accent) 100%);
    color: var(--white);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: bold;
    display: inline-block;
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.challenge-card h3 {
    color: var(--gray-800);
    font-size: 1.3rem;
    margin-bottom: 1rem;
    line-height: 1.4;
}

.challenge-content {
    color: var(--gray-600);
    font-size: 1rem;
    margin-bottom: 2rem;
    line-height: 1.8;
}

.options-container {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.option-btn {
    background: var(--gray-100);
    border: 2px solid var(--gray-200);
    padding: 1rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
    font-size: 1rem;
    color: var(--gray-700);
}

.option-btn:hover {
    background: var(--gray-200);
    border-color: var(--gray-300);
}

.option-btn.selected {
    background: var(--primary);
    border-color: var(--primary);
    color: var(--white);
}

.challenge-actions {
    display: flex;
    gap: 1rem;
    justify-content: space-between;
    align-items: center;
}

.hint-btn {
    background: var(--accent);
    color: var(--gray-800);
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: bold;
}

.hint-btn:hover {
    background: #e6a800;
    transform: translateY(-1px);
}

.submit-btn {
    background: linear-gradient(135deg, var(--blue) 0%, var(--purple) 100%);
    color: var(--white);
    border: none;
    padding: 0.75rem 2rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-weight: bold;
    font-size: 1rem;
}

.submit-btn:disabled {
    background: var(--gray-400);
    cursor: not-allowed;
    transform: none;
}

.submit-btn:not(:disabled):hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-hover);
}

.feedback-card {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    margin-bottom: 1rem;
}

.feedback-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.feedback-icon {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--white);
}

.feedback-icon.correct {
    background: var(--success);
}

.feedback-icon.incorrect {
    background: var(--danger);
}

.feedback-content {
    color: var(--gray-600);
    margin-bottom: 1rem;
    line-height: 1.8;
}

.feedback-explanation {
    background: var(--gray-100);
    padding: 1rem;
    border-radius: var(--border-radius);
    margin-bottom: 1.5rem;
    border-left: 4px solid var(--blue);
}

.next-btn {
    background: linear-gradient(135deg, var(--secondary) 0%, var(--primary) 100%);
    color: var(--white);
    border: none;
    padding: 0.75rem 2rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-weight: bold;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin: 0 auto;
}

.next-btn:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-hover);
}

.game-complete {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    text-align: center;
}

.complete-header {
    margin-bottom: 2rem;
}

.complete-header i {
    font-size: 4rem;
    color: var(--accent);
    margin-bottom: 1rem;
}

.complete-header h2 {
    color: var(--gray-800);
    font-size: 2rem;
}

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

.final-stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.final-score,
.final-accuracy {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--primary);
}

.achievements {
    margin-bottom: 2rem;
}

.play-again-btn {
    background: linear-gradient(135deg, var(--blue) 0%, var(--purple) 100%);
    color: var(--white);
    border: none;
    padding: 1rem 2rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-weight: bold;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin: 0 auto;
}

.play-again-btn:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-hover);
}

.progress-container {
    max-width: 800px;
    margin: 0 auto;
}

.level-card {
    background: linear-gradient(135deg, var(--purple) 0%, var(--blue) 100%);
    color: var(--white);
    border-radius: var(--border-radius);
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

.level-info {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.level-number {
    font-size: 4rem;
    font-weight: bold;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.level-details {
    flex: 1;
}

.level-details h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

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

.xp-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent) 0%, var(--secondary) 100%);
    transition: width 0.3s ease;
    width: 0%;
}

.xp-text {
    font-size: 0.9rem;
    opacity: 0.9;
}

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

.stats-section h3 {
    color: var(--gray-800);
    font-size: 1.3rem;
    margin-bottom: 1.5rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--gray-100);
    border-radius: var(--border-radius);
}

.stat-item i {
    font-size: 1.5rem;
    color: var(--primary);
}

.stat-value {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--gray-800);
}

.stat-name {
    font-size: 0.9rem;
    color: var(--gray-600);
}

.achievements-section {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
}

.achievements-section h3 {
    color: var(--gray-800);
    font-size: 1.3rem;
    margin-bottom: 1.5rem;
}

.achievements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 1rem;
}

.achievement-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1rem;
    border-radius: var(--border-radius);
    text-align: center;
    transition: var(--transition);
}

.achievement-item.earned {
    background: linear-gradient(135deg, var(--accent) 0%, var(--secondary) 100%);
    color: var(--white);
}

.achievement-item.locked {
    background: var(--gray-200);
    color: var(--gray-500);
}

.achievement-item i {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.achievement-item span {
    font-size: 0.8rem;
    font-weight: bold;
}

.settings-container {
    max-width: 600px;
    margin: 0 auto;
}

.settings-group {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

.settings-group h3 {
    color: var(--gray-800);
    font-size: 1.3rem;
    margin-bottom: 1.5rem;
    border-bottom: 2px solid var(--gray-200);
    padding-bottom: 0.5rem;
}

.setting-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
    border-bottom: 1px solid var(--gray-200);
}

.setting-item:last-child {
    border-bottom: none;
}

.setting-item label {
    display: flex;
    align-items: center;
    gap: 1rem;
    color: var(--gray-700);
    font-weight: 500;
}

.setting-item i {
    color: var(--primary);
    width: 20px;
}

.setting-item select {
    padding: 0.5rem;
    border: 2px solid var(--gray-300);
    border-radius: var(--border-radius);
    background: var(--white);
    color: var(--gray-700);
    cursor: pointer;
}

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

.setting-actions {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.action-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 1rem;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-weight: bold;
    font-size: 1rem;
}

.export-btn {
    background: var(--blue);
    color: var(--white);
}

.import-btn {
    background: var(--purple);
    color: var(--white);
}

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

.action-btn:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-hover);
}

.faq-container {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    max-width: 800px;
    margin: 0 auto;
}

.faq-container h2 {
    color: var(--gray-800);
    font-size: 1.8rem;
    margin-bottom: 2rem;
    text-align: center;
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.faq-item {
    border: 1px solid var(--gray-200);
    border-radius: var(--border-radius);
    overflow: hidden;
    transition: var(--transition);
}

.faq-item:hover {
    box-shadow: var(--shadow);
}

.faq-question {
    width: 100%;
    background: none;
    border: none;
    padding: 1.5rem 0;
    text-align: left;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--gray-800);
    transition: var(--transition);
}

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

.faq-icon {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary);
    transition: var(--transition);
}

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

.faq-answer {
    padding-bottom: 1.5rem;
    color: var(--gray-600);
    line-height: 1.8;
    animation: fadeIn 0.3s ease-in-out;
}

.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--white);
    border-top: 1px solid var(--gray-200);
    display: flex;
    justify-content: space-around;
    padding: 0.5rem 0;
    box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.1);
    z-index: 1000;
}

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

.nav-item.active {
    color: var(--primary);
}

.nav-item:hover {
    color: var(--primary);
    background: var(--gray-100);
}

.nav-item i {
    font-size: 1.2rem;
    margin-bottom: 0.2rem;
}

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

footer {
    background: var(--gray-800);
    color: var(--white);
    text-align: center;
    padding: 1rem;
    font-size: 0.9rem;
    margin-top: 2rem;
}

.app-footer {
    background: var(--gray-800);
    color: var(--white);
    text-align: center;
    padding: 1rem;
    font-size: 0.9rem;
    margin-top: 2rem;
}

.app-footer p {
    margin: 0;
    color: var(--white);
    font-size: 0.9rem;
    line-height: 1.4;
}

.app-footer strong {
    color: var(--white);
    font-weight: 600;
}

.app-footer .footer-link {
    color: var(--white);
    text-decoration: none;
    cursor: pointer;
    transition: opacity 0.3s ease;
}

.app-footer .footer-link:hover {
    opacity: 0.8;
}

.app-footer .footer-link:visited {
    color: var(--white);
}

.app-footer .footer-link:active {
    color: var(--white);
}

.hidden {
    display: none !important;
}

@media (max-width: 768px) {
    .header-content h1 {
        font-size: 1.2rem;
    }
    
    .welcome-card {
        padding: 1.5rem;
    }
    
    .welcome-card h2 {
        font-size: 1.5rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .game-modes {
        grid-template-columns: 1fr;
    }
    
    .level-info {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
    }
    
    .level-number {
        font-size: 3rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .challenge-actions {
        flex-direction: column;
    }
    
    .final-stats {
        grid-template-columns: 1fr;
    }
    
    .setting-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
}

@media (max-width: 480px) {
    main {
        padding: 0.5rem;
    }
    
    .welcome-card,
    .challenge-card,
    .feedback-card,
    .game-complete {
        padding: 1rem;
    }
    
    .nav-item span {
        display: none;
    }
    
    .nav-item {
        min-width: 50px;
    }
    
    .faq-question {
        font-size: 1rem;
        padding: 1rem 0;
    }
}

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

.pulse {
    animation: pulse 0.5s ease-in-out;
}

@keyframes shake {
    0%, 100% {
        transform: translateX(0);
    }
    25% {
        transform: translateX(-5px);
    }
    75% {
        transform: translateX(5px);
    }
}

.shake {
    animation: shake 0.5s ease-in-out;
}