/* Remove default browser spacing */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* Main page */
body {
    background-color: #0f172a;
    color: white;
    font-family: Arial, sans-serif;

    min-height: 100vh;

    display: flex;
    justify-content: center;
    align-items: center;
}

/* Main game container */
.container {
    width: 400px;
    text-align: center;
    padding: 20px;
}

/* Heading */
header h1 {
    font-size: 64px;
    margin-bottom: 5px;
}

header p {
    color: #94a3b8;
    margin-bottom: 25px;
}
.score-container {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-bottom: 20px;
}

.score-box {
    background-color: #1e293b;
    padding: 12px 24px;
    border-radius: 10px;
    font-size: 20px;
    font-weight: bold;
}
/* New Game button */
#new-game {
    background-color: #6366f1;
    color: white;
    border: none;

    padding: 12px 28px;
    border-radius: 8px;

    font-size: 16px;
    font-weight: bold;

    cursor: pointer;
    margin-bottom: 25px;

    transition: background-color 0.2s, transform 0.15s;
}

/* Button hover effect */
#new-game:hover {
    background-color: #4f46e5;
    transform: translateY(-2px);
}

/* Game board */
#game-board {
    background-color: #1e293b;
    width: 360px;
    height: 360px;
    margin: 0 auto;
    padding: 10px;
    border-radius: 12px;
    position: relative;
}

/* Empty cells */
.cell-layer {
    position: absolute;
    inset: 10px;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(4, 1fr);
    gap: 10px;
}

.cell {
    background-color: #334155;
    border-radius: 8px;
}

.tile-layer {
    position: absolute;
    inset: 10px;
}

.tile {
    position: absolute;
    top: 0;
    left: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 8px;
    font-size: 32px;
    font-weight: bold;
    color: white;
    transition:
        left 140ms ease,
        top 140ms ease,
        transform 120ms ease,
        opacity 120ms ease;
}
.tile.merged {
    animation: merge-pop 160ms ease;
}

@keyframes merge-pop {
    0% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.15);
    }

    100% {
        transform: scale(1);
    }
}
.instructions {
    color: #94a3b8;
    margin-top: 20px;
    font-size: 14px;
}
/* Mobile responsiveness */
@media (max-width: 450px) {
    .container {
        width: 100%;
        padding: 15px;
    }

    #game-board {
        width: 100%;
        height: auto;
        aspect-ratio: 1 / 1;
    }

    .score-container {
        gap: 15px;
    }

    .score-box {
        padding: 10px 16px;
        font-size: 16px;
    }
}
/* Number tiles */
.tile {
    display: flex;
    justify-content: center;
    align-items: center;

    font-size: 32px;
    font-weight: bold;

    color: white;
}

/* Individual tile colours */
/* Empty cells */
.tile {
    background-color: #334155;
    border-radius: 8px;

    display: flex;
    justify-content: center;
    align-items: center;

    font-size: 32px;
    font-weight: bold;
    color: white;
}

/* Number tile colours */
.tile-2 {
    background-color: #475569;
}

.tile-4 {
    background-color: #64748b;
}

.tile-8 {
    background-color: #2563eb;
}

.tile-16 {
    background-color: #7c3aed;
}

.tile-32 {
    background-color: #9333ea;
}

.tile-64 {
    background-color: #c026d3;
}

.tile-128 {
    background-color: #db2777;
    font-size: 28px;
}

.tile-256 {
    background-color: #ea580c;
    font-size: 28px;
}

.tile-512 {
    background-color: #d97706;
    font-size: 28px;
}

.tile-1024 {
    background-color: #ca8a04;
    font-size: 24px;
}

.tile-2048 {
    background-color: #eab308;
    color: #172033;
    font-size: 24px;
}
#game-over {
    color: #f87171;
    font-size: 18px;
    font-weight: bold;
    margin-top: 16px;
}
/* Smooth tile appearance */
.tile {
    animation: tile-appear 0.12s ease-out;
}

@keyframes tile-appear {
    from {
        transform: scale(0.85);
        opacity: 0.5;
    }

    to {
        transform: scale(1);
        opacity: 1;
    }
}
.tile-128,
.tile-256,
.tile-512 {
    font-size: 28px;
}

.tile-1024,
.tile-2048,
.tile-4096,
.tile-8192 {
    font-size: 22px;
}