:root {
    --bg: #0b1220;
    --panel: #111a2e;
    --text: #e7eefc;
    --muted: #a8b3cc;
    --accent: #7aa2ff;
    --danger: #ff6b6b;
    --border: rgba(231, 238, 252, 0.14);
    --surface: #0f1830;
}

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

body {
    font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, sans-serif;
    background: radial-gradient(1000px 600px at 20% 10%, rgba(122, 162, 255, 0.22), transparent),
        radial-gradient(900px 600px at 90% 10%, rgba(255, 107, 107, 0.12), transparent), var(--bg);
    color: var(--text);
    min-height: 100vh;
    padding: 50px 30px 30px 70px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    width: 100%;
    max-width: 900px;
    display: grid;
    gap: 10px;
}

.header-content {
    display: flex;
    align-items: center;
    gap: 12px;
}

h1 {
    color: var(--text);
    font-size: 2em;
    margin: 0;
    font-weight: 600;
    line-height: 1;
}

.game-info {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.score-container,
.high-score-container {
    display: flex;
    flex-direction: column;
    gap: 2px;
    text-align: center;
    padding: 10px;
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 12px;
}

.label {
    font-size: 0.75rem;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

#score,
#highScore {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--accent);
}

#gameCanvas {
    border: 2px solid var(--border);
    border-radius: 12px;
    background: #000;
    display: block;
    width: 100%;
    max-width: 100%;
    height: 400px;
    margin: 0 auto;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
}

.controls {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    padding: 12px 28px;
    font-size: 1rem;
    font-weight: 500;
    border: 1px solid var(--border);
    border-radius: 8px;
    cursor: pointer;
    background: var(--panel);
    color: var(--text);
    transition: all 0.15s ease;
}

.btn:hover:not(:disabled) {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
    transform: translateY(-1px);
}

.btn:active:not(:disabled) {
    transform: scale(0.98);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.instructions {
    background: var(--panel);
    border: 1px solid var(--border);
    padding: 16px;
    border-radius: 12px;
}

.instructions h3 {
    color: var(--text);
    margin-bottom: 16px;
    font-size: 1.25rem;
    font-weight: 600;
}

.instructions ul {
    list-style: none;
    color: var(--muted);
    margin: 0;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.instructions li {
    margin: 0;
    font-size: 1rem;
    padding-left: 24px;
    position: relative;
}

.instructions li::before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--accent);
}

.game-over {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.85);
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.game-over-content {
    background: var(--panel);
    border: 1px solid var(--border);
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
    text-align: center;
    min-width: 320px;
    max-width: 90%;
}

.game-over-content h2 {
    color: var(--danger);
    font-size: 2em;
    margin: 0 0 16px 0;
    font-weight: 600;
}

.game-over-content p {
    font-size: 1.125rem;
    color: var(--text);
    margin-bottom: 24px;
}

#finalScore {
    color: var(--accent);
    font-weight: 600;
    font-size: 1.5em;
}

.hidden {
    display: none !important;
}

.back-button {
    flex-shrink: 0;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text);
    text-decoration: none;
    transition: all 0.15s ease;
}

.back-button:hover {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

@media (max-width: 768px) {
    body {
        padding: 70px 20px 20px 20px;
    }

    .container {
        max-width: 600px;
        gap: 16px;
    }

    .instructions ul {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 600px) {
    body {
        padding: 70px 16px 16px 16px;
    }

    .container {
        gap: 16px;
    }

    .back-button {
        top: 16px;
        left: 16px;
    }

    h1 {
        font-size: 2rem;
    }

    .game-info {
        grid-template-columns: 1fr 1fr;
        gap: 12px;
    }

    .score-container,
    .high-score-container {
        padding: 16px;
    }

    #score,
    #highScore {
        font-size: 2rem;
    }

    #gameCanvas {
        max-width: 100%;
        height: auto;
        aspect-ratio: 1;
    }

    .btn {
        padding: 10px 20px;
        font-size: 0.9375rem;
    }
}