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

:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --secondary: #ec4899;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --card-bg: #ffffff;
    --text-dark: #1f2937;
    --text-light: #6b7280;
    --border-radius: 16px;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
    --shadow-hover: 0 20px 40px rgba(0, 0, 0, 0.2);

    /* Category Colors */
    --basic-directions: #3b82f6;
    --basic-directions-light: #60a5fa;
    --position: #8b5cf6;
    --position-light: #a78bfa;
    --distance: #ec4899;
    --distance-light: #f472b6;
    --landmarks: #10b981;
    --landmarks-light: #34d399;
    --movement: #f59e0b;
    --movement-light: #fbbf24;
    --orientation: #ef4444;
    --orientation-light: #f87171;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--background);
    min-height: 100vh;
    padding: 20px;
    color: var(--text-dark);
    animation: gradientShift 15s ease infinite;
    background-size: 200% 200%;
}

@keyframes gradientShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    animation: fadeIn 0.6s ease;
}

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

/* Header */
header {
    text-align: center;
    margin-bottom: 40px;
    color: white;
}

header h1 {
    font-size: 3.5rem;
    margin-bottom: 10px;
    text-shadow: 3px 3px 6px rgba(0, 0, 0, 0.3);
    animation: slideDown 0.8s ease;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.95;
    margin-bottom: 30px;
}

/* Mode Switcher */
.mode-switcher {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.mode-btn {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 15px 30px;
    background: rgba(255, 255, 255, 0.2);
    border: 2px solid rgba(255, 255, 255, 0.3);
    color: white;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.mode-btn .icon {
    font-size: 1.5rem;
}

.mode-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-3px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

.mode-btn.active {
    background: white;
    color: var(--primary);
    border-color: white;
    box-shadow: 0 10px 30px rgba(255, 255, 255, 0.3);
}

/* Progress Stats */
.progress-stats {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

.stat-item {
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    padding: 20px 35px;
    border-radius: var(--border-radius);
    border: 2px solid rgba(255, 255, 255, 0.3);
    text-align: center;
    transition: all 0.3s ease;
}

.stat-item:hover {
    transform: scale(1.05);
    background: rgba(255, 255, 255, 0.3);
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: white;
}

.stat-label {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.9);
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* Mode Content */
.mode-content {
    display: none;
}

.mode-content.active {
    display: block;
    animation: fadeIn 0.5s ease;
}

/* Browse Mode */
.controls {
    background: var(--card-bg);
    padding: 30px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    margin-bottom: 30px;
    animation: slideUp 0.6s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.search-box {
    margin-bottom: 25px;
}

#searchInput {
    width: 100%;
    padding: 18px 25px;
    font-size: 1.1rem;
    border: 3px solid #e5e7eb;
    border-radius: var(--border-radius);
    transition: all 0.3s ease;
}

#searchInput:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
    transform: translateY(-2px);
}

.filter-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.filter-btn {
    padding: 12px 24px;
    border: 2px solid var(--primary);
    background: white;
    color: var(--primary);
    border-radius: 30px;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 600;
    transition: all 0.3s ease;
}

.filter-btn:hover {
    background: #f3f4f6;
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(99, 102, 241, 0.2);
}

.filter-btn.active {
    background: var(--primary);
    color: white;
    box-shadow: 0 5px 15px rgba(99, 102, 241, 0.4);
}

/* Category-specific filter button colors */
.filter-btn[data-category="basic-directions"] {
    border-color: var(--basic-directions);
    color: var(--basic-directions);
}

.filter-btn[data-category="basic-directions"]:hover {
    box-shadow: 0 5px 15px rgba(59, 130, 246, 0.2);
}

.filter-btn[data-category="basic-directions"].active {
    background: var(--basic-directions);
    color: white;
    box-shadow: 0 5px 15px rgba(59, 130, 246, 0.4);
}

.filter-btn[data-category="position"] {
    border-color: var(--position);
    color: var(--position);
}

.filter-btn[data-category="position"]:hover {
    box-shadow: 0 5px 15px rgba(139, 92, 246, 0.2);
}

.filter-btn[data-category="position"].active {
    background: var(--position);
    color: white;
    box-shadow: 0 5px 15px rgba(139, 92, 246, 0.4);
}

.filter-btn[data-category="distance"] {
    border-color: var(--distance);
    color: var(--distance);
}

.filter-btn[data-category="distance"]:hover {
    box-shadow: 0 5px 15px rgba(236, 72, 153, 0.2);
}

.filter-btn[data-category="distance"].active {
    background: var(--distance);
    color: white;
    box-shadow: 0 5px 15px rgba(236, 72, 153, 0.4);
}

.filter-btn[data-category="landmarks"] {
    border-color: var(--landmarks);
    color: var(--landmarks);
}

.filter-btn[data-category="landmarks"]:hover {
    box-shadow: 0 5px 15px rgba(16, 185, 129, 0.2);
}

.filter-btn[data-category="landmarks"].active {
    background: var(--landmarks);
    color: white;
    box-shadow: 0 5px 15px rgba(16, 185, 129, 0.4);
}

.filter-btn[data-category="movement"] {
    border-color: var(--movement);
    color: var(--movement);
}

.filter-btn[data-category="movement"]:hover {
    box-shadow: 0 5px 15px rgba(245, 158, 11, 0.2);
}

.filter-btn[data-category="movement"].active {
    background: var(--movement);
    color: white;
    box-shadow: 0 5px 15px rgba(245, 158, 11, 0.4);
}

.filter-btn[data-category="orientation"] {
    border-color: var(--orientation);
    color: var(--orientation);
}

.filter-btn[data-category="orientation"]:hover {
    box-shadow: 0 5px 15px rgba(239, 68, 68, 0.2);
}

.filter-btn[data-category="orientation"].active {
    background: var(--orientation);
    color: white;
    box-shadow: 0 5px 15px rgba(239, 68, 68, 0.4);
}

.stats {
    text-align: center;
    color: white;
    font-size: 1.2rem;
    margin-bottom: 25px;
    font-weight: 500;
}

.expressions-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 25px;
    margin-bottom: 40px;
}

.expression-card {
    background: var(--card-bg);
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    border-left: 5px solid var(--primary);
    cursor: pointer;
}

.expression-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-hover);
}

/* Category-specific card colors */
.expression-card[data-category="basic-directions"] {
    border-left-color: var(--basic-directions);
}

.expression-card[data-category="basic-directions"]:hover {
    border-left-color: var(--basic-directions-light);
}

.expression-card[data-category="position"] {
    border-left-color: var(--position);
}

.expression-card[data-category="position"]:hover {
    border-left-color: var(--position-light);
}

.expression-card[data-category="distance"] {
    border-left-color: var(--distance);
}

.expression-card[data-category="distance"]:hover {
    border-left-color: var(--distance-light);
}

.expression-card[data-category="landmarks"] {
    border-left-color: var(--landmarks);
}

.expression-card[data-category="landmarks"]:hover {
    border-left-color: var(--landmarks-light);
}

.expression-card[data-category="movement"] {
    border-left-color: var(--movement);
}

.expression-card[data-category="movement"]:hover {
    border-left-color: var(--movement-light);
}

.expression-card[data-category="orientation"] {
    border-left-color: var(--orientation);
}

.expression-card[data-category="orientation"]:hover {
    border-left-color: var(--orientation-light);
}

.expression-text {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 12px;
}

.expression-example {
    font-size: 1rem;
    color: var(--text-light);
    font-style: italic;
    margin-bottom: 15px;
    line-height: 1.6;
}

.expression-category {
    display: inline-block;
    padding: 6px 16px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 20px;
    font-size: 0.75rem;
    color: white;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Category-specific badge colors */
.expression-category[data-category="basic-directions"] {
    background: linear-gradient(135deg, var(--basic-directions), var(--basic-directions-light));
}

.expression-category[data-category="position"] {
    background: linear-gradient(135deg, var(--position), var(--position-light));
}

.expression-category[data-category="distance"] {
    background: linear-gradient(135deg, var(--distance), var(--distance-light));
}

.expression-category[data-category="landmarks"] {
    background: linear-gradient(135deg, var(--landmarks), var(--landmarks-light));
}

.expression-category[data-category="movement"] {
    background: linear-gradient(135deg, var(--movement), var(--movement-light));
}

.expression-category[data-category="orientation"] {
    background: linear-gradient(135deg, var(--orientation), var(--orientation-light));
}

/* Flashcards Mode */
.flashcard-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--card-bg);
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    margin-bottom: 30px;
    flex-wrap: wrap;
    gap: 20px;
}

.category-select-wrapper {
    display: flex;
    align-items: center;
    gap: 15px;
    font-weight: 600;
}

.category-select-wrapper label {
    color: var(--text-dark);
}

.category-select-wrapper select,
#quizCategory,
#quizLength {
    padding: 12px 20px;
    border: 2px solid #e5e7eb;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.category-select-wrapper select:hover,
#quizCategory:hover,
#quizLength:hover {
    border-color: var(--primary);
}

.category-select-wrapper select:focus,
#quizCategory:focus,
#quizLength:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}

.flashcard-container {
    max-width: 700px;
    margin: 0 auto;
}

.flashcard-progress {
    text-align: center;
    font-size: 1.3rem;
    font-weight: 600;
    color: white;
    margin-bottom: 25px;
}

.flashcard {
    perspective: 1000px;
    height: 450px;
    margin-bottom: 30px;
    cursor: pointer;
}

.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

.flashcard.flipped .flashcard-inner {
    transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-hover);
    display: flex;
    align-items: center;
    justify-content: center;
}

.flashcard-front {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
}

.flashcard-back {
    background: linear-gradient(135deg, var(--success), #059669);
    color: white;
    transform: rotateY(180deg);
}

/* Category-specific flashcard colors */
.flashcard[data-category="basic-directions"] .flashcard-front {
    background: linear-gradient(135deg, var(--basic-directions), var(--basic-directions-light));
}

.flashcard[data-category="basic-directions"] .flashcard-back {
    background: linear-gradient(135deg, var(--basic-directions-light), var(--basic-directions));
}

.flashcard[data-category="position"] .flashcard-front {
    background: linear-gradient(135deg, var(--position), var(--position-light));
}

.flashcard[data-category="position"] .flashcard-back {
    background: linear-gradient(135deg, var(--position-light), var(--position));
}

.flashcard[data-category="distance"] .flashcard-front {
    background: linear-gradient(135deg, var(--distance), var(--distance-light));
}

.flashcard[data-category="distance"] .flashcard-back {
    background: linear-gradient(135deg, var(--distance-light), var(--distance));
}

.flashcard[data-category="landmarks"] .flashcard-front {
    background: linear-gradient(135deg, var(--landmarks), var(--landmarks-light));
}

.flashcard[data-category="landmarks"] .flashcard-back {
    background: linear-gradient(135deg, var(--landmarks-light), var(--landmarks));
}

.flashcard[data-category="movement"] .flashcard-front {
    background: linear-gradient(135deg, var(--movement), var(--movement-light));
}

.flashcard[data-category="movement"] .flashcard-back {
    background: linear-gradient(135deg, var(--movement-light), var(--movement));
}

.flashcard[data-category="orientation"] .flashcard-front {
    background: linear-gradient(135deg, var(--orientation), var(--orientation-light));
}

.flashcard[data-category="orientation"] .flashcard-back {
    background: linear-gradient(135deg, var(--orientation-light), var(--orientation));
}

.flashcard-content {
    text-align: center;
    padding: 40px;
}

.hint {
    font-size: 0.9rem;
    opacity: 0.8;
    margin-bottom: 25px;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.flashcard-text {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 25px;
    line-height: 1.3;
}

.flashcard-example {
    font-size: 1.8rem;
    font-style: italic;
    margin-bottom: 25px;
    line-height: 1.4;
}

.flashcard-text-small {
    font-size: 1.3rem;
    font-weight: 600;
    opacity: 0.9;
}

.flashcard-category {
    display: inline-block;
    padding: 8px 20px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 25px;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.flashcard-navigation {
    display: flex;
    gap: 15px;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
}

.nav-btn,
.action-btn {
    padding: 15px 30px;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.nav-btn {
    background: var(--card-bg);
    color: var(--primary);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.nav-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}

.action-btn {
    background: var(--primary);
    color: white;
    box-shadow: 0 5px 20px rgba(99, 102, 241, 0.4);
}

.action-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(99, 102, 241, 0.5);
}

.action-btn.success {
    background: var(--success);
    box-shadow: 0 5px 20px rgba(16, 185, 129, 0.4);
}

.action-btn.success:hover {
    background: #059669;
}

.action-btn.large {
    padding: 20px 50px;
    font-size: 1.3rem;
}

/* Quiz Mode */
.quiz-setup,
.quiz-active,
.quiz-results,
.quiz-review {
    background: var(--card-bg);
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    max-width: 800px;
    margin: 0 auto;
}

.quiz-setup h2,
.quiz-review h2 {
    color: var(--text-dark);
    margin-bottom: 30px;
    font-size: 2rem;
}

.quiz-options {
    display: flex;
    gap: 30px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.option-group {
    flex: 1;
    min-width: 250px;
}

.option-group label {
    display: block;
    margin-bottom: 10px;
    font-weight: 600;
    color: var(--text-dark);
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 2px solid #e5e7eb;
    flex-wrap: wrap;
    gap: 15px;
}

.quiz-progress,
.quiz-score-live {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-dark);
}

.quiz-question-container {
    margin-bottom: 30px;
}

.quiz-question {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 30px;
    line-height: 1.5;
}

.quiz-answers {
    display: grid;
    gap: 15px;
}

.answer-option {
    padding: 20px 25px;
    background: #f9fafb;
    border: 3px solid #e5e7eb;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1.1rem;
    font-weight: 500;
}

.answer-option:hover {
    background: #f3f4f6;
    border-color: var(--primary);
    transform: translateX(5px);
}

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

.answer-option.correct {
    background: var(--success);
    color: white;
    border-color: var(--success);
    animation: correctPulse 0.5s ease;
}

.answer-option.incorrect {
    background: var(--danger);
    color: white;
    border-color: var(--danger);
    animation: shake 0.5s ease;
}

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

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-10px); }
    75% { transform: translateX(10px); }
}

.answer-option.disabled {
    cursor: not-allowed;
    opacity: 0.6;
}

/* Quiz Results */
.results-container {
    text-align: center;
}

.results-container h2 {
    font-size: 2.5rem;
    margin-bottom: 30px;
    color: var(--text-dark);
}

.final-score {
    margin: 40px 0;
}

.score-circle {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin: 0 auto;
    box-shadow: 0 15px 40px rgba(99, 102, 241, 0.4);
    animation: scaleIn 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes scaleIn {
    from {
        transform: scale(0);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

.score-number {
    font-size: 4rem;
    font-weight: 700;
    color: white;
}

.score-total {
    font-size: 1.5rem;
    color: rgba(255, 255, 255, 0.9);
}

.score-percentage {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 20px;
}

.score-message {
    font-size: 1.3rem;
    color: var(--text-light);
    margin-bottom: 40px;
}

.results-actions {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

/* Quiz Review */
.review-container {
    margin-bottom: 30px;
}

.review-item {
    background: #f9fafb;
    padding: 25px;
    border-radius: 12px;
    margin-bottom: 20px;
    border-left: 5px solid var(--text-light);
}

.review-item.correct {
    border-left-color: var(--success);
}

.review-item.incorrect {
    border-left-color: var(--danger);
}

.review-question {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 15px;
}

.review-answers {
    display: grid;
    gap: 10px;
}

.review-answer {
    padding: 12px 18px;
    background: white;
    border-radius: 8px;
    border: 2px solid #e5e7eb;
}

.review-answer.user-answer {
    border-color: var(--danger);
    background: #fee2e2;
}

.review-answer.correct-answer {
    border-color: var(--success);
    background: #d1fae5;
    font-weight: 600;
}

.no-results {
    text-align: center;
    padding: 80px 20px;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.no-results h2 {
    color: var(--text-light);
    font-size: 1.8rem;
    margin-bottom: 15px;
}

.no-results p {
    color: var(--text-light);
    font-size: 1.1rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 2.5rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .mode-switcher {
        flex-direction: column;
    }

    .mode-btn {
        width: 100%;
        justify-content: center;
    }

    .expressions-grid {
        grid-template-columns: 1fr;
    }

    .filter-buttons {
        justify-content: center;
    }

    .flashcard {
        height: 400px;
    }

    .flashcard-text {
        font-size: 2rem;
    }

    .flashcard-example {
        font-size: 1.4rem;
    }

    .quiz-options {
        flex-direction: column;
    }

    .score-circle {
        width: 150px;
        height: 150px;
    }

    .score-number {
        font-size: 3rem;
    }

    .quiz-setup,
    .quiz-active,
    .quiz-results,
    .quiz-review {
        padding: 25px;
    }
}

/* Loading Animation */
@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}