:root {
    --primary-color: #4f46e5;
    --secondary-color: #7c3aed;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --dark-color: #1f2937;
    --light-color: #f8fafc;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    margin: 0;
}

.navbar {
    background: rgba(255, 255, 255, 0.95) !important;
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.navbar-brand {
    font-weight: bold;
    color: var(--primary-color) !important;
    font-size: 1.5rem;
}

.nav-link {
    color: var(--dark-color) !important;
    font-weight: 500;
    transition: color 0.3s ease;
}

    .nav-link:hover {
        color: var(--primary-color) !important;
    }

.container-fluid {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    margin: 20px;
    padding: 30px;
    min-height: calc(100vh - 140px);
}

.game-card {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    padding: 30px;
    margin: 15px 0;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

    .game-card:hover {
        transform: translateY(-5px);
        box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
    }

.btn-game {
    background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    border-radius: 15px;
    padding: 12px 30px;
    font-weight: 600;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
}

    .btn-game:hover {
        transform: translateY(-2px);
        box-shadow: 0 8px 25px rgba(79, 70, 229, 0.3);
        color: white;
    }

.score-card {
    background: linear-gradient(45deg, var(--success-color), #059669);
    color: white;
    border-radius: 15px;
    padding: 20px;
    text-align: center;
}

.badge-item {
    display: inline-block;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    padding: 8px 12px;
    margin: 5px;
    font-size: 0.9rem;
}

.progress-modern {
    height: 10px;
    border-radius: 50px;
    background: rgba(255, 255, 255, 0.2);
    overflow: hidden;
}

.progress-bar-modern {
    background: linear-gradient(45deg, var(--success-color), #10b981);
    height: 100%;
    border-radius: 50px;
    transition: width 0.6s ease;
}

.category-icon {
    font-size: 2rem;
    margin-bottom: 15px;
    color: var(--primary-color);
}

.category-card {
    transition: all 0.3s ease;
    border: none;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

    .category-card:hover {
        box-shadow: 0 4px 20px rgba(0,0,0,0.15);
        transform: translateY(-2px);
    }

.loading-fallback {
    min-height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
}

/* Flash Cards CSS */
.flash-card-container {
    perspective: 1000px;
    height: 400px;
    margin: 20px 0;
}

.flash-card {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.8s;
    transform-style: preserve-3d;
    cursor: pointer;
}

    .flash-card.flipped {
        transform: rotateY(180deg);
    }

.flash-card-front, .flash-card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.flash-card-front {
    background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
    color: white;
}

.flash-card-back {
    background: linear-gradient(45deg, var(--success-color), #059669);
    color: white;
    transform: rotateY(180deg);
}

.card-content {
    padding: 30px;
    width: 100%;
}

    .card-content h2, .card-content h3 {
        text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
        word-wrap: break-word;
    }

.animate-fade-in {
    animation: fadeIn 0.5s ease-in;
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.floating-element {
    animation: float 3s ease-in-out infinite;
}

@@keyframes float {
    0%, 100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-10px);
    }
}

.question-card {
    background: white;
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    margin: 20px 0;
}

.answer-option {
    background: rgba(79, 70, 229, 0.1);
    border: 2px solid transparent;
    border-radius: 15px;
    padding: 15px 20px;
    margin: 10px 0;
    cursor: pointer;
    transition: all 0.3s ease;
}

    .answer-option:hover {
        background: rgba(79, 70, 229, 0.2);
        border-color: var(--primary-color);
        transform: translateX(5px);
    }

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

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

.timer-circle {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: conic-gradient(var(--warning-color) 0deg, rgba(245, 158, 11, 0.2) 0deg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.2rem;
}

.hint-box {
    background: rgba(245, 158, 11, 0.1);
    border-left: 4px solid var(--warning-color);
    border-radius: 10px;
    padding: 15px;
    margin: 15px 0;
}

.leaderboard-item {
    background: white;
    border-radius: 15px;
    padding: 20px;
    margin: 10px 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease;
}

    .leaderboard-item:hover {
        transform: translateX(5px);
    }

.rank-badge {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    color: white;
}

.rank-1 {
    background: linear-gradient(45deg, #ffd700, #ffed4e);
}

.rank-2 {
    background: linear-gradient(45deg, #c0c0c0, #e5e7eb);
}

.rank-3 {
    background: linear-gradient(45deg, #cd7f32, #92400e);
}

.rank-other {
    background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
}