.game-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    text-align: center;
}

.card-pool {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 2rem;
    min-height: 120px;
    padding: 1rem;
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-md);
}

.level-indicator {
    font-size: 1.2rem;
    font-weight: bold;
    color: var(--color-primary);
    margin: 1rem 0;
}

.controls {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.btn-secondary {
    background: var(--color-surface);
    color: var(--color-primary);
    border: 1px solid var(--color-primary);
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-secondary:hover {
    background: rgba(187, 134, 252, 0.1);
}

.btn-secondary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.timeline-container {
    padding: 2rem;
    border: 2px dashed var(--color-text-sub);
    border-radius: var(--radius-lg);
    background: rgba(0, 0, 0, 0.2);
    min-height: 200px;
    display: flex;
    justify-content: flex-start;
    align-items: center;
    flex-wrap: nowrap;
    overflow-x: auto;
    gap: 1rem;
    position: relative;
}

.timeline-container::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 2rem;
    right: 2rem;
    height: 0;
    border-top: 2px dashed var(--color-text-sub);
    z-index: 0;
    opacity: 0.5;
}

.card {
    background: var(--color-surface);
    color: var(--color-text-main);
    border: 1px solid var(--color-primary);
    border-radius: var(--radius-md);
    padding: 1rem;
    width: 150px;
    cursor: grab;
    user-select: none;
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    position: relative;
    z-index: 2;
}

.card:active {
    cursor: grabbing;
    transform: scale(1.05);
}

.card.dragging {
    opacity: 0.5;
}

.card h3 {
    font-size: 1rem;
    margin: 0;
    pointer-events: none;
}

.card .year {
    font-size: 0.8rem;
    color: var(--color-text-sub);
    margin-top: 0.5rem;
    font-family: var(--font-family-mono);
    display: none;
    /* Hide year until revealed */
}

.card.revealed .year {
    display: block;
}

.card.correct {
    border-color: var(--color-secondary);
    background: rgba(3, 218, 198, 0.1);
}

.card.incorrect {
    border-color: var(--color-accent);
    background: rgba(207, 102, 121, 0.1);
}

.result-message {
    margin-top: 1rem;
    font-weight: bold;
    min-height: 1.5rem;
}

/* Animations */
@keyframes shake {
    0% {
        transform: translateX(0);
    }

    25% {
        transform: translateX(-5px);
    }

    50% {
        transform: translateX(5px);
    }

    75% {
        transform: translateX(-5px);
    }

    100% {
        transform: translateX(0);
    }
}

.shake {
    animation: shake 0.4s ease-in-out;
}