:root {
    --bg-gradient-start: #0f172a;
    --bg-gradient-end: #1e293b;
    --accent: #22c55e;
    --accent-dark: #16a34a;
    --accent-glow: rgba(34, 197, 94, 0.4);
    --danger: #ef4444;
    --food: #f59e0b;
    --text: #e2e8f0;
    --text-muted: #94a3b8;
    --panel: rgba(15, 23, 42, 0.85);
    --panel-border: rgba(34, 197, 94, 0.25);
}

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

html, body {
    height: 100%;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    color: var(--text);
    background: radial-gradient(circle at top, var(--bg-gradient-end), var(--bg-gradient-start));
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    overflow-x: hidden;
}

.game-wrapper {
    width: 100%;
    max-width: 520px;
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.game-header {
    text-align: center;
}

.game-header h1 {
    font-size: 2.4rem;
    letter-spacing: 2px;
    background: linear-gradient(135deg, var(--accent), #84cc16);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 30px var(--accent-glow);
}

.subtitle {
    color: var(--text-muted);
    margin-top: 6px;
    font-size: 0.95rem;
}

.hud {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.hud-item {
    background: var(--panel);
    border: 1px solid var(--panel-border);
    border-radius: 10px;
    padding: 10px 14px;
    text-align: center;
    backdrop-filter: blur(8px);
}

.hud-label {
    display: block;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    color: var(--text-muted);
}

.hud-value {
    display: block;
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--accent);
    margin-top: 2px;
}

.canvas-container {
    position: relative;
    border-radius: 14px;
    overflow: hidden;
    border: 2px solid var(--panel-border);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5), 0 0 30px var(--accent-glow);
    aspect-ratio: 1 / 1;
    background: #020617;
}

#game {
    display: block;
    width: 100%;
    height: 100%;
    image-rendering: pixelated;
}

.overlay {
    position: absolute;
    inset: 0;
    background: rgba(2, 6, 23, 0.85);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: opacity 0.3s ease;
}

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

.overlay-content {
    text-align: center;
    padding: 20px;
}

.overlay-content h2 {
    font-size: 2rem;
    color: var(--accent);
    margin-bottom: 10px;
}

.overlay-content p {
    color: var(--text-muted);
    margin-bottom: 18px;
}

.btn {
    background: linear-gradient(135deg, var(--accent), var(--accent-dark));
    color: #022c0b;
    border: none;
    padding: 12px 32px;
    font-size: 1rem;
    font-weight: 700;
    border-radius: 8px;
    cursor: pointer;
    letter-spacing: 1px;
    text-transform: uppercase;
    box-shadow: 0 4px 20px var(--accent-glow);
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 24px var(--accent-glow);
}

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

.controls-help {
    background: var(--panel);
    border: 1px solid var(--panel-border);
    border-radius: 10px;
    padding: 14px 18px;
    font-size: 0.9rem;
}

.controls-help h3 {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.controls-help ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

kbd {
    display: inline-block;
    background: #1e293b;
    border: 1px solid #334155;
    border-radius: 4px;
    padding: 2px 8px;
    font-size: 0.8rem;
    font-family: 'Consolas', monospace;
    color: var(--accent);
    margin: 0 2px;
}

.game-footer {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.8rem;
}

@media (max-width: 480px) {
    .game-header h1 { font-size: 1.8rem; }
    .hud-value { font-size: 1.2rem; }
    .overlay-content h2 { font-size: 1.5rem; }
}