:root {
    --primary-color: #4CAF50;
    --secondary-color: #2196F3;
    --background-color: #f5f5f5;
    --text-color: #333;
    --header-height: 60px;
    --footer-height: 50px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    background-color: white;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    height: var(--header-height);
}

nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--primary-color);
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 600;
}

.score-container {
    font-size: 1.2rem;
    font-weight: 500;
}

main {
    flex: 1;
    padding: 20px;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.game-container {
    background: white;
    border-radius: 12px;
    padding: 20px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 20px;
}

.game-controls {
    grid-column: 1 / -1;
    display: flex;
    gap: 10px;
    justify-content: center;
}

#gameCanvas {
    background: #1a1a1a;
    border-radius: 8px;
    width: 780px;
    height: 520px;
    margin: 0 auto;
    display: block;
}

.btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.2s;
}

.btn:hover {
    background-color: #3d8b40;
}

.game-info {
    padding: 20px;
    background: #f8f8f8;
    border-radius: 8px;
}

.high-scores {
    margin-bottom: 20px;
}

.high-scores h2, .controls-info h2 {
    color: var(--primary-color);
    margin-bottom: 10px;
    font-size: 1.2rem;
}

#leaderboard {
    background: white;
    border-radius: 6px;
    padding: 10px;
    max-height: 200px;
    overflow-y: auto;
}

.controls-info p {
    margin-bottom: 5px;
    font-size: 0.9rem;
}

footer {
    background-color: white;
    height: var(--footer-height);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 -2px 4px rgba(0,0,0,0.1);
}

@media (max-width: 768px) {
    .game-container {
        grid-template-columns: 1fr;
    }

    #gameCanvas {
        height: 400px;
    }
}