:root {
    /* Light theme variables */
    --bg-color: #f0f0f0;
    --text-color: #333;
    --game-bg: #ffffff;
    --grid-color: #e0e0e0;
    --snake-color: #4CAF50;
    --snake-head-color: #388E3C;
    --food-color: #f44336;
    --border-color: #ccc;
    --btn-bg: #2196F3;
    --btn-hover: #1976D2;
    --panel-bg: #ffffff;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-color: #ffffff;
    --game-bg: #2d2d2d;
    --grid-color: #404040;
    --snake-color: #66bb6a;
    --snake-head-color: #4caf50;
    --food-color: #ef5350;
    --border-color: #404040;
    --btn-bg: #42a5f5;
    --btn-hover: #1e88e5;
    --panel-bg: #2d2d2d;
    --shadow-color: rgba(0, 0, 0, 0.3);
}

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

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

.game-container {
    max-width: 800px;
    width: 100%;
    padding: 20px;
}

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

.score-container {
    font-size: 1.2rem;
    font-weight: bold;
}

.score-container span {
    margin-right: 20px;
}

.controls {
    display: flex;
    gap: 10px;
}

.btn {
    padding: 8px 16px;
    font-size: 1rem;
    background-color: var(--btn-bg);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

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

.game-board {
    width: 100%;
    aspect-ratio: 1;
    background-color: var(--game-bg);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    display: grid;
    grid-template-columns: repeat(20, 1fr);
    grid-template-rows: repeat(20, 1fr);
    position: relative;
    box-shadow: 0 4px 6px var(--shadow-color);
    background-image: linear-gradient(var(--grid-color) 1px, transparent 1px),
                      linear-gradient(90deg, var(--grid-color) 1px, transparent 1px);
    background-size: calc(100% / 20) calc(100% / 20);
    background-position: center center;
}

.snake-segment {
    background-color: var(--snake-color);
    border-radius: 4px;
    margin: 1px;
    position: relative;
}

.snake-segment::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 70%;
    height: 70%;
    background-color: rgba(255, 255, 255, 0.2);
    border-radius: 2px;
}

.snake-head {
    background-color: var(--snake-head-color);
    border-radius: 4px;
    margin: 1px;
    position: relative;
}

.snake-head::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 40%;
    height: 40%;
    background-color: rgba(255, 255, 255, 0.4);
    border-radius: 50%;
}

.snake-head::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 20%;
    height: 20%;
    background-color: rgba(0, 0, 0, 0.3);
    border-radius: 50%;
}

.food {
    background-color: var(--food-color);
    border-radius: 50%;
    margin: 1px;
    position: relative;
    box-shadow: 0 0 8px var(--food-color);
}

.food::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60%;
    height: 60%;
    background-color: rgba(255, 255, 255, 0.4);
    border-radius: 50%;
}

.mobile-controls {
    display: none;
    margin-top: 20px;
}

.direction-buttons {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

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

.direction-btn {
    width: 60px;
    height: 60px;
    font-size: 24px;
    background-color: var(--btn-bg);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    transition: background-color 0.3s;
}

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

.settings-panel {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: var(--panel-bg);
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 4px 6px var(--shadow-color);
    z-index: 1000;
}

.settings-content {
    margin: 20px 0;
}

.setting-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.setting-item select {
    padding: 5px;
    border-radius: 4px;
    border: 1px solid var(--border-color);
    background-color: var(--game-bg);
    color: var(--text-color);
}

.game-over {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: var(--panel-bg);
    padding: 30px;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 4px 6px var(--shadow-color);
    z-index: 1000;
}

.welcome-screen {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: var(--panel-bg);
    padding: 30px;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 4px 6px var(--shadow-color);
    z-index: 1000;
}

.hidden {
    display: none;
}

@media (max-width: 600px) {
    .mobile-controls {
        display: block;
    }

    .game-header {
        flex-direction: column;
        gap: 10px;
    }

    .controls {
        width: 100%;
        justify-content: center;
    }

    .score-container {
        text-align: center;
    }
}