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

:root {
    --bg-color: #f0f0f0;
    --container-bg: white;
    --text-color: #333;
    --border-color: #333;
    --grid-bg: #ddd;
    --cell-bg: white;
    --snake-color: #4CAF50;
    --food-color: #f44336;
    --button-bg: #4CAF50;
    --button-hover: #45a049;
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #fff;
    --border-color: #666;
    --grid-bg: #404040;
    --cell-bg: #333;
    --snake-color: #66bb6a;
    --food-color: #ef5350;
    --button-bg: #66bb6a;
    --button-hover: #81c784;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: var(--bg-color);
    font-family: Arial, sans-serif;
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

.game-container {
    position: relative;
    background-color: var(--container-bg);
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.theme-toggle {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    padding: 5px;
    color: var(--text-color);
}

.score {
    font-size: 24px;
}

#game-board {
    display: grid;
    grid-template-columns: repeat(20, 20px);
    grid-template-rows: repeat(20, 20px);
    gap: 1px;
    background-color: var(--grid-bg);
    border: 2px solid var(--border-color);
    transition: background-color 0.3s, border-color 0.3s;
}

.cell {
    width: 20px;
    height: 20px;
    background-color: var(--cell-bg);
}

.snake {
    background-color: var(--snake-color);
    border-radius: 2px;
}

.food {
    background-color: var(--food-color);
    border-radius: 50%;
}

#game-over {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: var(--container-bg);
    padding: 20px;
    border-radius: 10px;
    text-align: center;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
    z-index: 100;
}

.hidden {
    display: none;
}

#restart-button {
    margin-top: 15px;
    padding: 10px 20px;
    font-size: 16px;
    background-color: var(--button-bg);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

#restart-button:hover {
    background-color: var(--button-hover);
}

.mobile-controls {
    display: none;
    flex-direction: column;
    align-items: center;
    margin-top: 20px;
    gap: 10px;
}

.horizontal-controls {
    display: flex;
    gap: 20px;
}

.control-btn {
    width: 60px;
    height: 60px;
    font-size: 24px;
    background-color: var(--button-bg);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 0.3s;
}

.control-btn:hover {
    background-color: var(--button-hover);
}

@media (max-width: 768px) {
    .game-container {
        padding: 10px;
    }

    #game-board {
        grid-template-columns: repeat(20, 15px);
        grid-template-rows: repeat(20, 15px);
    }

    .cell {
        width: 15px;
        height: 15px;
    }

    .mobile-controls {
        display: flex;
    }
}