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

:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --success: #22c55e;
    --success-light: #dcfce7;
    --error: #ef4444;
    --error-light: #fee2e2;
    --warning: #f59e0b;
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --card-bg: rgba(255, 255, 255, 0.95);
    --text: #1e293b;
    --text-light: #64748b;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg-gradient);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 1rem;
}

.container {
    width: 100%;
    max-width: 500px;
}

.screen {
    display: none;
    animation: fadeIn 0.3s ease;
}

.screen.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Écran d'accueil */
.title {
    text-align: center;
    font-size: 2.5rem;
    color: white;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
    margin-bottom: 0.5rem;
}

.emoji {
    display: inline-block;
    animation: bounce 2s infinite;
}

.emoji:last-child {
    animation-delay: 0.5s;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.subtitle {
    text-align: center;
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

.mode-selection {
    background: var(--card-bg);
    border-radius: 1.5rem;
    padding: 1.5rem;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

.mode-selection h2 {
    text-align: center;
    color: var(--text);
    font-size: 1.3rem;
    margin-bottom: 1rem;
}

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

.mode-btn {
    display: grid;
    grid-template-columns: auto 1fr auto;
    grid-template-rows: auto auto;
    align-items: center;
    gap: 0.25rem 1rem;
    padding: 1rem 1.25rem;
    border: 2px solid #e2e8f0;
    border-radius: 1rem;
    background: white;
    cursor: pointer;
    transition: all 0.2s ease;
}

.mode-btn:hover {
    border-color: var(--primary);
    transform: translateX(5px);
    box-shadow: 0 5px 15px rgba(99, 102, 241, 0.2);
}

.mode-btn:active {
    transform: scale(0.98);
}

.mode-icon {
    font-size: 2rem;
    grid-row: span 2;
}

.mode-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text);
}

.mode-details {
    font-size: 0.9rem;
    color: var(--text-light);
    justify-self: end;
}

.mode-questions {
    font-size: 0.85rem;
    color: var(--primary);
    font-weight: 500;
}

/* Écran de jeu */
#screen-game {
    background: var(--card-bg);
    border-radius: 1.5rem;
    padding: 1.5rem;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

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

.timer {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text);
}

.timer.warning {
    color: var(--warning);
    animation: pulse 1s infinite;
}

.timer.danger {
    color: var(--error);
    animation: pulse 0.5s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.6; }
}

.progress {
    font-size: 1.1rem;
    color: var(--text-light);
    font-weight: 500;
}

.progress-bar {
    height: 8px;
    background: #e2e8f0;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 2rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), #a855f7);
    border-radius: 4px;
    transition: width 0.3s ease;
    width: 0%;
}

.question-card {
    background: linear-gradient(135deg, #f8fafc, #f1f5f9);
    border-radius: 1rem;
    padding: 2rem;
    margin-bottom: 1.5rem;
}

.question {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary);
}

.operator {
    font-size: 2.5rem;
    color: var(--text-light);
}

.equals {
    font-size: 2.5rem;
    color: var(--text-light);
}

.answer-box {
    font-size: 3rem;
    font-weight: 700;
    color: var(--text-light);
    min-width: 80px;
    text-align: center;
}

#answer-form {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.answer-input {
    flex: 1;
    padding: 1rem 1.25rem;
    font-size: 1.5rem;
    border: 2px solid #e2e8f0;
    border-radius: 1rem;
    text-align: center;
    outline: none;
    transition: border-color 0.2s;
}

.answer-input:focus {
    border-color: var(--primary);
}

.submit-btn {
    padding: 1rem 1.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    color: white;
    background: var(--primary);
    border: none;
    border-radius: 1rem;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}

.submit-btn:hover {
    background: var(--primary-dark);
}

.submit-btn:active {
    transform: scale(0.95);
}

.feedback {
    text-align: center;
    font-size: 1.2rem;
    font-weight: 600;
    min-height: 2rem;
    padding: 0.5rem;
    border-radius: 0.5rem;
    transition: all 0.2s;
}

.feedback.correct {
    color: var(--success);
    background: var(--success-light);
    animation: correctPop 0.3s ease;
}

.feedback.wrong {
    color: var(--error);
    background: var(--error-light);
    animation: shake 0.3s ease;
}

@keyframes correctPop {
    0% { transform: scale(0.8); }
    50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

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

/* Écran de résultats */
#screen-results {
    background: var(--card-bg);
    border-radius: 1.5rem;
    padding: 1.5rem;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

.results-header {
    text-align: center;
    margin-bottom: 1.5rem;
}

.results-icon {
    font-size: 4rem;
    display: block;
    animation: bounce 1s ease infinite;
}

.results-header h2 {
    font-size: 2rem;
    color: var(--text);
}

.results-header.timeout .results-icon::after {
    content: "⏱️";
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.stat-card {
    background: #f8fafc;
    border-radius: 1rem;
    padding: 1rem;
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.stat-icon {
    font-size: 1.5rem;
}

.stat-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text);
}

.stat-card.correct .stat-value {
    color: var(--success);
}

.stat-card.wrong .stat-value {
    color: var(--error);
}

.stat-card.score .stat-value {
    color: var(--primary);
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-light);
}

.errors-section {
    background: var(--error-light);
    border-radius: 1rem;
    padding: 1rem;
    margin-bottom: 1.5rem;
    display: none;
}

.errors-section.visible {
    display: block;
}

.errors-section h3 {
    color: var(--error);
    font-size: 1rem;
    margin-bottom: 0.75rem;
}

.errors-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.error-item {
    background: white;
    padding: 0.5rem 0.75rem;
    border-radius: 0.5rem;
    font-size: 0.9rem;
    color: var(--text);
}

.play-again-btn {
    width: 100%;
    padding: 1rem;
    font-size: 1.2rem;
    font-weight: 600;
    color: white;
    background: linear-gradient(135deg, var(--primary), #a855f7);
    border: none;
    border-radius: 1rem;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.play-again-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(99, 102, 241, 0.3);
}

.play-again-btn:active {
    transform: scale(0.98);
}

/* Responsive */
@media (max-width: 400px) {
    .title {
        font-size: 2rem;
    }

    .number {
        font-size: 2.5rem;
    }

    .operator, .equals {
        font-size: 2rem;
    }

    .answer-box {
        font-size: 2.5rem;
        min-width: 60px;
    }

    .answer-input {
        font-size: 1.25rem;
        padding: 0.75rem 1rem;
    }

    .submit-btn {
        padding: 0.75rem 1rem;
    }

    .stats-grid {
        grid-template-columns: 1fr 1fr;
        gap: 0.75rem;
    }

    .stat-value {
        font-size: 1.5rem;
    }
}

@media (min-width: 600px) {
    .modes {
        flex-direction: row;
    }

    .mode-btn {
        flex: 1;
        display: flex;
        flex-direction: column;
        text-align: center;
        padding: 1.5rem 1rem;
    }

    .mode-icon {
        font-size: 2.5rem;
        margin-bottom: 0.5rem;
    }

    .mode-details, .mode-questions {
        justify-self: center;
    }
}