:root {
    --bg-color: #1a1d21;
    --board-bg-color: #000000;
    --text-color: #e0e0e0;
    --header-color: #ffffff;
    --accent-color: #4a90e2;
    --info-box-bg: #2c313a;
    --grid-bg-color: #bbada0;
    --tile-bg-color: #cdc1b4;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-family);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
}

.game-container {
    display: flex;
    flex-direction: column;
    gap: 20px;
    width: 100%;
    max-width: 1050px;
    align-items: center;
}

.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    max-width: 800px;
}

.game-header h1 {
    color: var(--header-color);
    font-size: 2.5rem;
    margin: 0;
}

.back-link {
    background-color: var(--info-box-bg);
    color: var(--text-color);
    padding: 10px 15px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: bold;
    transition: background-color 0.2s;
}

.back-link:hover {
    background-color: #454c5a;
}

.game-body {
    display: flex;
    gap: 20px;
}

.game-board-container {
    position: relative;
    border: 4px solid var(--info-box-bg);
    border-radius: 8px;
    overflow: hidden;
}

.game-info {
    display: flex;
    flex-direction: column;
    gap: 15px;
    width: 200px;
}

.info-box {
    background-color: var(--info-box-bg);
    padding: 20px;
    border-radius: 8px;
    text-align: center;
}

.info-box h3 {
    margin: 0 0 10px;
    font-size: 1.2rem;
    opacity: 0.8;
}

.info-box p {
    margin: 0;
    font-size: 1.8rem;
    font-weight: bold;
}

#new-game-btn, #try-again-btn {
    background-color: var(--accent-color);
    color: var(--header-color);
    border: none;
    border-radius: 8px;
    padding: 15px 30px;
    font-size: 1.2rem;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.2s;
}

#new-game-btn:hover, #try-again-btn:hover {
    background-color: #3a80d2;
}

.grid-container {
    position: relative;
    background-color: var(--grid-bg-color);
    border-radius: 6px;
    padding: 15px;
    display: inline-block;
}

.grid {
    display: grid;
    grid-template-columns: repeat(4, 100px);
    grid-template-rows: repeat(4, 100px);
    gap: 15px;
}

.grid-cell {
    width: 100px;
    height: 100px;
    background-color: var(--tile-bg-color);
    border-radius: 3px;
}

.tile {
    --x: 0;
    --y: 0;
    position: absolute;
    top: calc(var(--y) * (100px + 15px) + 15px);
    left: calc(var(--x) * (100px + 15px) + 15px);
    width: 100px;
    height: 100px;
    border-radius: 3px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 55px;
    font-weight: bold;
    transition: 100ms ease-in-out;
    animation-duration: 200ms;
    animation-timing-function: ease-in-out;
}

.tile.tile-new {
    animation-name: appear;
}

.tile.tile-merged {
    animation-name: pop;
}

@keyframes appear {
    from {
        transform: scale(0);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

@keyframes pop {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.2);
    }
    100% {
        transform: scale(1);
    }
}

#game-over-message {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.75);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    gap: 20px;
}

#game-over-message.hidden {
    display: none;
}

#overlay-title {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--header-color);
    margin: 0;
}

.tile-2 { background-color: #eee4da; color: #776e65; }
.tile-4 { background-color: #ede0c8; color: #776e65; }
.tile-8 { background-color: #f2b179; color: #f9f6f2; }
.tile-16 { background-color: #f59563; color: #f9f6f2; }
.tile-32 { background-color: #f67c5f; color: #f9f6f2; }
.tile-64 { background-color: #f65e3b; color: #f9f6f2; }
.tile-128 { background-color: #edcf72; color: #f9f6f2; }
.tile-256 { background-color: #edcc61; color: #f9f6f2; }
.tile-512 { background-color: #edc850; color: #f9f6f2; }
.tile-1024 { background-color: #edc53f; color: #f9f6f2; }
.tile-2048 { background-color: #edc22e; color: #f9f6f2; }
