/* ==========================================================================
   Neon Highway - Space Edition
   Header matches site; game area full viewport.
   ========================================================================== */

:root {
  --bg-page: #0c0e10;
  --bg-card: #15181b;
  --border: #2a2e33;
  --text: #e8eaed;
  --text-muted: #9aa0a6;
  --accent: #00d4ff;
  --accent-glow: rgba(0, 212, 255, 0.4);
  --radius: 8px;
  --radius-sm: 6px;
  --space: 1rem;
  --font-sans: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }

body {
  font-family: var(--font-sans);
  margin: 0;
  min-height: 100vh;
  background: #0a0a0f;
  color: var(--text);
  overflow-x: hidden;
}

/* ==========================================================================
   Game viewport and HUD
   ========================================================================== */

#gameContainer {
  position: relative;
  width: 100%;
  height: calc(100vh - 60px);
  min-height: 400px;
}

#gameCanvas {
  display: block;
  width: 100%;
  height: 100%;
  background: radial-gradient(ellipse at center, rgba(16, 32, 62, 0.35) 0%, rgba(0, 0, 20, 0.9) 100%);
}

#score {
  position: absolute;
  top: 1rem;
  left: 1rem;
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--accent);
  background: rgba(0, 0, 0, 0.5);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(0, 212, 255, 0.3);
  text-shadow: 0 0 12px var(--accent-glow);
  backdrop-filter: blur(6px);
}

#musicBtn {
  position: absolute;
  top: 1rem;
  right: 1rem;
  padding: 0.5rem 1rem;
  font: inherit;
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--accent);
  background: rgba(0, 212, 255, 0.15);
  border: 1px solid rgba(0, 212, 255, 0.4);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 0.2s, transform 0.2s;
}

#musicBtn:hover {
  background: rgba(0, 212, 255, 0.25);
  transform: scale(1.03);
}

#musicBtn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ==========================================================================
   Game over overlay
   ========================================================================== */

#gameOver {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
  background: rgba(0, 0, 0, 0.88);
  padding: 2rem;
  border-radius: var(--radius);
  border: 2px solid var(--accent);
  box-shadow: 0 0 32px var(--accent-glow);
  display: none;
  backdrop-filter: blur(10px);
  min-width: 280px;
}

#gameOver h2 {
  margin: 0 0 1rem;
  font-size: 1.75rem;
  font-weight: 600;
  color: #ff6b6b;
  text-shadow: 0 0 16px rgba(255, 107, 107, 0.5);
}

#gameOver p {
  margin: 0.5rem 0;
  font-size: 1rem;
  color: var(--text);
}