/* CSS Reset and Base Styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --primary-color: #4ade80;
    --primary-dark: #22c55e;
    --secondary-color: #3b82f6;
    --background-dark: #0f172a;
    --background-card: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --canvas-bg: #0f172a;
    --snake-head: #4ade80;
    --snake-body: #22c55e;
    --food-color: #ef4444;
}

html {
    font-size: 16px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, var(--background-dark) 0%, #1a1a2e 100%);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    width: 100%;
}

/* Header Styles */
header {
    text-align: center;
    padding: 1rem 0;
}

header h1 {
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: 0 0 30px rgba(74, 222, 128, 0.3);
}

/* Main Content */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* Game Info Section */
.game-info {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.score-container {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.score-box {
    background: var(--background-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 0.75rem 1.5rem;
    text-align: center;
    min-width: 120px;
}

.score-box .label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.25rem;
}

.score-box .value {
    display: block;
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary-color);
}

.score-box.high-score .value {
    color: var(--warning-color);
}

.speed-indicator {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
}

.speed-indicator .label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.speed-bar {
    width: 150px;
    height: 8px;
    background: var(--background-card);
    border-radius: 4px;
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.speed-fill {
    height: 100%;
    width: 10%;
    background: linear-gradient(90deg, var(--primary-color), var(--danger-color));
    border-radius: 4px;
    transition: width 0.3s ease;
}

/* Game Canvas Wrapper */
.game-wrapper {
    position: relative;
    width: 100%;
    aspect-ratio: 1;
    max-width: 500px;
    margin: 0 auto;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 0 40px rgba(74, 222, 128, 0.1),
                0 4px 20px rgba(0, 0, 0, 0.3);
}

#game-canvas {
    display: block;
    width: 100%;
    height: 100%;
    background: var(--canvas-bg);
    border: 2px solid var(--border-color);
    border-radius: 16px;
}

/* Game Overlay */
.game-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(15, 23, 42, 0.95);
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 16px;
    opacity: 1;
    transition: opacity 0.3s ease;
}

.game-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.overlay-content {
    text-align: center;
    padding: 2rem;
}

.overlay-content h2 {
    font-size: 1.75rem;
    margin-bottom: 0.75rem;
    color: var(--primary-color);
}

.overlay-content p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

/* Button Styles */
.btn {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: var(--background-dark);
    border: none;
    padding: 0.875rem 2rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(74, 222, 128, 0.4);
}

.btn:active {
    transform: translateY(0);
}

/* Controls Info */
.controls-info {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.controls-info p {
    margin: 0.25rem 0;
}

.controls-info kbd {
    display: inline-block;
    background: var(--background-card);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 0.15rem 0.5rem;
    font-family: inherit;
    font-size: 0.8rem;
    margin: 0 0.1rem;
}

.mobile-controls {
    display: none;
}

/* Mobile Control Buttons */
.mobile-controls-buttons {
    display: none;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    margin-top: 1rem;
}

.horizontal-controls {
    display: flex;
    gap: 0.5rem;
}

.control-btn {
    width: 60px;
    height: 60px;
    background: var(--background-card);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    color: var(--text-primary);
    font-size: 1.5rem;
    cursor: pointer;
    transition: all 0.15s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.control-btn:active {
    background: var(--primary-dark);
    border-color: var(--primary-color);
    transform: scale(0.95);
}

/* Footer */
footer {
    text-align: center;
    padding: 1.5rem 0;
    margin-top: auto;
}

footer p {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

/* Responsive Styles */
@media (max-width: 600px) {
    html {
        font-size: 14px;
    }

    .container {
        padding: 0.75rem;
    }

    header h1 {
        font-size: 1.75rem;
    }

    .score-box {
        min-width: 100px;
        padding: 0.5rem 1rem;
    }

    .score-box .value {
        font-size: 1.5rem;
    }

    .desktop-controls {
        display: none;
    }

    .mobile-controls {
        display: block;
    }

    .mobile-controls-buttons {
        display: flex;
    }

    .game-wrapper {
        max-width: 100%;
    }
}

@media (max-width: 400px) {
    .score-container {
        gap: 0.5rem;
    }

    .score-box {
        min-width: 80px;
        padding: 0.5rem 0.75rem;
    }

    .control-btn {
        width: 50px;
        height: 50px;
        font-size: 1.25rem;
    }
}

/* Animations */
@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.score-box.pulse {
    animation: pulse 0.3s ease;
}

/* Game Over specific styles */
.game-over .overlay-content h2 {
    color: var(--danger-color);
}

.new-high-score .overlay-content h2 {
    color: var(--warning-color);
}