/* ========================================
   CSS Variables & Reset
   ======================================== */

:root {
    /* Colors */
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary-color: #8b5cf6;
    --accent-color: #ec4899;

    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #3b82f6;

    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --bg-card: #1e293b;

    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;

    --border-radius: 12px;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.4);

    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

/* ========================================
   Navigation
   ======================================== */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
    transition: var(--transition);
}

.navbar.scrolled {
    background: rgba(15, 23, 42, 0.98);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-brand i {
    color: var(--primary-color);
    -webkit-text-fill-color: var(--primary-color);
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 1.5rem;
    cursor: pointer;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
}

.nav-link.active {
    color: var(--primary-color);
    background: rgba(99, 102, 241, 0.15);
}

/* Progress Bar */
.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    z-index: 1001;
    transition: width 0.1s ease;
}

/* ========================================
   Hero Section
   ======================================== */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding-top: 80px;
    position: relative;
    overflow: hidden;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 900px;
    padding: 2rem;
}

.hero-title {
    font-size: 4rem;
    font-weight: 800;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: fadeInUp 0.8s ease;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    animation: fadeInUp 1s ease;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
    animation: fadeInUp 1.2s ease;
}

.stat-card {
    background: var(--bg-card);
    padding: 2rem 1rem;
    border-radius: var(--border-radius);
    border: 1px solid rgba(99, 102, 241, 0.2);
    transition: var(--transition);
}

.stat-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary-color);
    box-shadow: 0 10px 30px rgba(99, 102, 241, 0.3);
}

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

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

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

.hero-animation {
    position: absolute;
    inset: 0;
    overflow: hidden;
    opacity: 0.1;
    pointer-events: none;
}

.formula-float {
    position: absolute;
    font-size: 1.5rem;
    animation: float 20s infinite ease-in-out;
}

.formula-float:nth-child(1) {
    top: 20%;
    left: 10%;
    animation-delay: 0s;
}

.formula-float:nth-child(2) {
    top: 60%;
    right: 15%;
    animation-delay: 5s;
}

.formula-float:nth-child(3) {
    bottom: 20%;
    left: 50%;
    animation-delay: 10s;
}

/* ========================================
   Sections
   ======================================== */

.section {
    padding: 6rem 0;
    min-height: 100vh;
}

.section-dark {
    background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
}

.section-title {
    font-size: 3rem;
    text-align: center;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
}

.section-title i {
    color: var(--primary-color);
}

.section-description {
    text-align: center;
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 4rem;
}

.course-intro {
    max-width: 800px;
    margin: 0 auto 4rem;
    text-align: center;
}

.lead {
    font-size: 1.2rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ========================================
   Identity Cards
   ======================================== */

.identities-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.identity-card {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 2rem;
    border: 2px solid rgba(99, 102, 241, 0.2);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.identity-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    transform: scaleX(0);
    transition: var(--transition);
}

.identity-card:hover::before {
    transform: scaleX(1);
}

.identity-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-color);
    box-shadow: var(--shadow-lg);
}

.identity-card.special {
    border-color: var(--accent-color);
    background: linear-gradient(135deg, rgba(236, 72, 153, 0.05), rgba(99, 102, 241, 0.05));
}

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

.identity-number {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.2rem;
}

.identity-header h3 {
    flex: 1;
    font-size: 1.3rem;
}

.identity-formula {
    background: rgba(99, 102, 241, 0.05);
    padding: 2rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    text-align: center;
    font-size: 1.3rem;
    border: 1px solid rgba(99, 102, 241, 0.2);
}

.identity-example {
    background: rgba(16, 185, 129, 0.05);
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid var(--success-color);
    margin-bottom: 1.5rem;
}

.identity-example h4 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    color: var(--success-color);
}

.identity-example p {
    margin: 0;
}

/* ========================================
   Tips Section
   ======================================== */

.tips-section {
    background: var(--bg-card);
    padding: 3rem;
    border-radius: var(--border-radius);
    margin-top: 3rem;
}

.tips-section h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 2rem;
    font-size: 1.8rem;
}

.tips-section h3 i {
    color: var(--warning-color);
}

.tips-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.tip-card {
    background: rgba(99, 102, 241, 0.05);
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
}

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

.tip-card h4 {
    margin-bottom: 0.5rem;
}

.tip-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* ========================================
   FlashCards
   ======================================== */

.flashcards-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.flashcard-counter {
    font-size: 1.5rem;
    font-weight: 700;
}

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

.flashcard {
    perspective: 1000px;
    height: 400px;
    margin-bottom: 2rem;
    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);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 3rem;
    box-shadow: var(--shadow-lg);
}

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

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

.flashcard-content {
    text-align: center;
}

.flashcard-content i {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    opacity: 0.9;
}

.flashcard-question,
.flashcard-answer {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.flashcard-hint {
    margin-top: auto;
    opacity: 0.7;
    font-size: 0.9rem;
}

.flashcard-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.flashcard-progress {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: var(--border-radius);
    border: 1px solid rgba(99, 102, 241, 0.2);
}

.progress-stats {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    gap: 2rem;
}

.progress-stats .stat {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.1rem;
}

/* ========================================
   Games
   ======================================== */

.games-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.game-card {
    background: var(--bg-card);
    padding: 3rem 2rem;
    border-radius: var(--border-radius);
    text-align: center;
    border: 2px solid rgba(99, 102, 241, 0.2);
    transition: var(--transition);
}

.game-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-color);
    box-shadow: var(--shadow-lg);
}

.game-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
}

.game-icon i {
    font-size: 2.5rem;
}

.game-card h3 {
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.game-card p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.game-container {
    background: var(--bg-card);
    padding: 3rem;
    border-radius: var(--border-radius);
    margin-top: 3rem;
    border: 2px solid rgba(99, 102, 241, 0.2);
}

.game-container.hidden {
    display: none;
}

/* Memory Game */
.memory-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
    margin-bottom: 2rem;
}

.memory-card {
    aspect-ratio: 1;
    background: var(--bg-tertiary);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
    padding: 1rem;
    text-align: center;
}

.memory-card:hover {
    border-color: var(--primary-color);
}

.memory-card.flipped {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
}

.memory-card.matched {
    background: linear-gradient(135deg, var(--success-color), #059669);
    cursor: default;
}

/* Drag & Drop Game */
.dragdrop-container {
    display: grid;
    gap: 2rem;
}

.formula-target {
    background: var(--bg-tertiary);
    padding: 2rem;
    border-radius: 8px;
    border: 2px dashed rgba(99, 102, 241, 0.5);
    min-height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.formula-target.dragover {
    border-color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
}

.draggable-term {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    padding: 1rem 2rem;
    border-radius: 8px;
    cursor: move;
    transition: var(--transition);
}

.draggable-term:hover {
    transform: scale(1.05);
}

.terms-bank {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
    padding: 2rem;
    background: var(--bg-secondary);
    border-radius: 8px;
}

/* Speed Math Game */
.speed-question {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 2rem;
    padding: 2rem;
    background: rgba(99, 102, 241, 0.1);
    border-radius: 8px;
}

.speed-timer {
    font-size: 1.5rem;
    text-align: center;
    color: var(--warning-color);
    margin-bottom: 2rem;
}

.speed-input {
    width: 100%;
    max-width: 500px;
    margin: 0 auto 2rem;
    display: block;
}

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

.game-stat {
    background: var(--bg-tertiary);
    padding: 1.5rem;
    border-radius: 8px;
    text-align: center;
}

.game-stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
}

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

/* ========================================
   Quiz
   ======================================== */

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

.quiz-start {
    background: var(--bg-card);
    padding: 4rem;
    border-radius: var(--border-radius);
    text-align: center;
    border: 2px solid rgba(99, 102, 241, 0.2);
}

.quiz-info h3 {
    font-size: 2rem;
    margin-bottom: 2rem;
}

.quiz-features {
    list-style: none;
    margin-bottom: 3rem;
    text-align: left;
    max-width: 400px;
    margin-left: auto;
    margin-right: auto;
}

.quiz-features li {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    margin-bottom: 0.5rem;
    background: rgba(99, 102, 241, 0.05);
    border-radius: 8px;
}

.quiz-features i {
    color: var(--success-color);
}

.quiz-question-card {
    background: var(--bg-card);
    padding: 3rem;
    border-radius: var(--border-radius);
    border: 2px solid rgba(99, 102, 241, 0.2);
    margin-bottom: 2rem;
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.quiz-progress {
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.quiz-timer {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.2rem;
    color: var(--warning-color);
}

.quiz-question {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    line-height: 1.6;
}

.quiz-options {
    display: grid;
    gap: 1rem;
}

.quiz-option {
    background: var(--bg-tertiary);
    padding: 1.5rem;
    border-radius: 8px;
    border: 2px solid transparent;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.quiz-option:hover {
    border-color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
}

.quiz-option.selected {
    border-color: var(--primary-color);
    background: rgba(99, 102, 241, 0.2);
}

.quiz-option.correct {
    border-color: var(--success-color);
    background: rgba(16, 185, 129, 0.2);
}

.quiz-option.incorrect {
    border-color: var(--danger-color);
    background: rgba(239, 68, 68, 0.2);
}

.option-letter {
    width: 40px;
    height: 40px;
    background: var(--bg-secondary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

.quiz-explanation {
    background: rgba(59, 130, 246, 0.1);
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid var(--info-color);
    margin-top: 1rem;
}

.quiz-results {
    background: var(--bg-card);
    padding: 4rem;
    border-radius: var(--border-radius);
    text-align: center;
    border: 2px solid rgba(99, 102, 241, 0.2);
}

.results-score {
    font-size: 5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 1rem;
}

.results-message {
    font-size: 1.5rem;
    margin-bottom: 2rem;
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
}

/* ========================================
   Buttons
   ======================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 2rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    white-space: nowrap;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 2px solid rgba(99, 102, 241, 0.3);
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
}

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

.btn-success:hover {
    background: #059669;
    transform: translateY(-2px);
}

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

.btn-danger:hover {
    background: #dc2626;
    transform: translateY(-2px);
}

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

.btn-outline:hover {
    background: var(--primary-color);
    color: white;
}

.btn-icon {
    width: 50px;
    height: 50px;
    padding: 0;
    border-radius: 50%;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 2px solid rgba(99, 102, 241, 0.3);
}

.btn-icon:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-large {
    padding: 1.25rem 3rem;
    font-size: 1.2rem;
}

/* ========================================
   Modal
   ======================================== */

.modal {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.8);
    z-index: 2000;
    align-items: center;
    justify-content: center;
    padding: 2rem;
}

.modal.show {
    display: flex;
    animation: fadeIn 0.3s ease;
}

.modal-content {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    max-width: 800px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.3s ease;
}

.modal-header {
    padding: 2rem;
    border-bottom: 1px solid rgba(99, 102, 241, 0.2);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-close {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 1.5rem;
    cursor: pointer;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    transition: var(--transition);
}

.modal-close:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.modal-body {
    padding: 2rem;
}

/* ========================================
   Form Elements
   ======================================== */

input[type="text"],
input[type="number"],
textarea,
select {
    width: 100%;
    padding: 1rem;
    background: var(--bg-tertiary);
    border: 2px solid rgba(99, 102, 241, 0.2);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition);
}

input:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

/* ========================================
   Footer
   ======================================== */

.footer {
    background: var(--bg-secondary);
    padding: 3rem 0 1rem;
    border-top: 1px solid rgba(99, 102, 241, 0.2);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

.footer-section a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(99, 102, 241, 0.1);
    color: var(--text-muted);
}

/* ========================================
   Notifications
   ======================================== */

.notifications-container {
    position: fixed;
    top: 100px;
    right: 2rem;
    z-index: 3000;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.notification {
    background: var(--bg-card);
    padding: 1rem 1.5rem;
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
    box-shadow: var(--shadow-lg);
    animation: slideInRight 0.3s ease;
    max-width: 400px;
}

.notification.success {
    border-left-color: var(--success-color);
}

.notification.error {
    border-left-color: var(--danger-color);
}

/* ========================================
   Utilities
   ======================================== */

.hidden {
    display: none !important;
}

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

/* ========================================
   Animations
   ======================================== */

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

@keyframes slideUp {
    from {
        transform: translateY(50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

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

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) rotate(0deg);
    }
    25% {
        transform: translate(50px, -50px) rotate(5deg);
    }
    50% {
        transform: translate(0, -100px) rotate(-5deg);
    }
    75% {
        transform: translate(-50px, -50px) rotate(3deg);
    }
}

/* ========================================
   Responsive Design
   ======================================== */

@media (max-width: 768px) {
    .nav-toggle {
        display: block;
    }

    .nav-menu {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--bg-primary);
        flex-direction: column;
        padding: 1rem 2rem;
        gap: 0;
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: var(--transition);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }

    .nav-link {
        padding: 1rem;
        border-bottom: 1px solid rgba(99, 102, 241, 0.1);
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .identities-grid,
    .games-grid {
        grid-template-columns: 1fr;
    }

    .memory-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .flashcard {
        height: 350px;
    }

    .container {
        padding: 1rem;
    }

    .section {
        padding: 4rem 0;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }

    .flashcard-question,
    .flashcard-answer {
        font-size: 1.3rem;
    }

    .btn {
        padding: 0.75rem 1.5rem;
        font-size: 0.9rem;
    }
}

/* ========================================
   Print Styles
   ======================================== */

@media print {
    .navbar,
    .flashcards-controls,
    .flashcard-actions,
    .btn,
    .footer,
    #jeux,
    #qcm {
        display: none !important;
    }

    body {
        background: white;
        color: black;
    }

    .identity-card {
        break-inside: avoid;
    }
}