* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Arial', sans-serif;
}

:root {
    --bg-color: #f5f7fa;
    --container-bg: #ffffff;
    --text-color: #474747;
    --heading-color: #7986cb;
    --score-color: #5c6bc0;
    --game-board-bg: #f0f4f8;
    --game-board-border: #e8eaf6;
    --snake-color: #7986cb;
    --snake-head-color: #5c6bc0;
    --snake-pattern-color: #9fa8da;
    --button-color: #7986cb;
    --button-hover: #5c6bc0;
    --footer-text: #757575;
    --footer-border: #e8eaf6;
    --link-color: #5c6bc0;
    --link-hover: #3f51b5;
    --shadow-color: rgba(0, 0, 0, 0.05);
    --shadow-hover: rgba(0, 0, 0, 0.1);
    --toggle-bg: #f0f4f8;
    --toggle-icon: #5c6bc0;
}

.dark-mode {
    --bg-color: #1a1a2e;
    --container-bg: #16213e;
    --text-color: #e6e6e6;
    --heading-color: #a5b4fc;
    --score-color: #818cf8;
    --game-board-bg: #0f172a;
    --game-board-border: #1e293b;
    --snake-color: #818cf8;
    --snake-head-color: #a5b4fc;
    --snake-pattern-color: #c7d2fe;
    --button-color: #818cf8;
    --button-hover: #a5b4fc;
    --footer-text: #94a3b8;
    --footer-border: #1e293b;
    --link-color: #818cf8;
    --link-hover: #a5b4fc;
    --shadow-color: rgba(0, 0, 0, 0.2);
    --shadow-hover: rgba(0, 0, 0, 0.3);
    --toggle-bg: #0f172a;
    --toggle-icon: #f1f5f9;
}

body {
    background-color: var(--bg-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    color: var(--text-color);
    transition: background-color 0.3s ease;
}

.game-container {
    text-align: center;
    background-color: var(--container-bg);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 10px 30px var(--shadow-color);
    max-width: 600px;
    width: 95%;
    position: relative;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.header-controls {
    position: absolute;
    top: 1rem;
    right: 1rem;
    z-index: 20;
}

.theme-toggle {
    background-color: var(--toggle-bg);
    color: var(--toggle-icon);
    border: none;
    border-radius: 50%;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 5px var(--shadow-color);
}

.theme-toggle:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--shadow-hover);
}

.theme-toggle i {
    font-size: 1.2rem;
}

h1 {
    margin-bottom: 1.5rem;
    color: var(--heading-color);
    font-weight: 600;
    transition: color 0.3s ease;
}

.score-container {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: var(--score-color);
    transition: color 0.3s ease;
}

.game-board {
    background-color: var(--game-board-bg);
    border-radius: 8px;
    width: 400px;
    height: 400px;
    margin: 0 auto 1.5rem;
    position: relative;
    border: 2px solid var(--game-board-border);
    overflow: hidden;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.snake-segment {
    position: absolute;
    background-color: var(--snake-color);
    border-radius: 3px;
    width: 18px;
    height: 18px;
    z-index: 10;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s ease;
}

.snake-body-connector {
    position: absolute;
    background-color: var(--snake-color);
    width: 18px;
    height: 18px;
    z-index: 9;
    transition: background-color 0.3s ease;
}

.snake-head {
    background-color: var(--snake-head-color);
    border-radius: 6px;
    width: 20px;
    height: 20px;
    z-index: 11;
    transition: background-color 0.3s ease;
}

.snake-eye {
    position: absolute;
    background-color: white;
    width: 3px;
    height: 3px;
    border-radius: 50%;
    z-index: 12;
}

.snake-eye-right {
    right: 4px;
    top: 4px;
}

.snake-eye-left {
    right: 4px;
    top: 13px;
}

.snake-pattern {
    position: absolute;
    background-color: var(--snake-pattern-color);
    width: 4px;
    height: 4px;
    border-radius: 50%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 11;
    transition: background-color 0.3s ease;
}

.food {
    position: absolute;
    background-color: transparent;
    width: 18px;
    height: 18px;
    z-index: 5;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 16px;
    text-align: center;
    line-height: 1;
}

.controls {
    margin-top: 1rem;
}

button {
    background-color: var(--button-color);
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
}

button:hover {
    background-color: var(--button-hover);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px var(--shadow-hover);
}

.instructions {
    margin-top: 1rem;
    font-size: 0.9rem;
    color: var(--footer-text);
    transition: color 0.3s ease;
}

.footer {
    margin-top: 1.5rem;
    padding-top: 1rem;
    border-top: 1px solid var(--footer-border);
    font-size: 0.85rem;
    color: var(--footer-text);
    transition: color 0.3s ease, border-color 0.3s ease;
}

.footer a {
    color: var(--link-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 5px;
}

.footer a:hover {
    color: var(--link-hover);
    text-decoration: underline;
}

.footer a i {
    font-size: 1.1em;
}

@media (max-width: 500px) {
    .game-board {
        width: 300px;
        height: 300px;
    }
}