:root {
  --bg: #070b16;
  --panel: rgba(13, 20, 38, 0.92);
  --line: rgba(120, 160, 255, 0.25);
  --ink: #dfe8ff;
  --dim: #8fa0c8;
  --accent: #35e0ff;
  --accent2: #ff6b35;
  --good: #6dffb0;
  --bad: #ff4d6d;
}

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

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--ink);
  font-family: "Avenir Next", "Segoe UI", system-ui, -apple-system, sans-serif;
  overflow: hidden;
  -webkit-user-select: none;
  user-select: none;
  touch-action: none;
}

#stage {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

canvas#game {
  display: block;
  background: var(--bg);
  border-radius: 6px;
  touch-action: none;
}

/* ---------- overlay screens ---------- */

#overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
}

#overlay .screen {
  pointer-events: auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 26px 30px;
  max-width: min(560px, 92vw);
  max-height: 94vh;
  overflow-y: auto;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.6), 0 0 60px rgba(53, 224, 255, 0.08);
  backdrop-filter: blur(6px);
}

#overlay .screen.hidden { display: none; }
#overlay.hidden { display: none; }

.title {
  font-size: clamp(38px, 7vw, 58px);
  letter-spacing: 0.14em;
  font-weight: 800;
  color: #fff;
  text-shadow: 0 0 24px rgba(53, 224, 255, 0.65), 0 0 4px rgba(53, 224, 255, 0.8);
}
.title span { color: var(--accent); }

.tagline { color: var(--dim); letter-spacing: 0.08em; font-size: 14px; }

.heading {
  font-size: clamp(30px, 6vw, 44px);
  letter-spacing: 0.14em;
  font-weight: 800;
  color: #fff;
}
.heading.good { text-shadow: 0 0 22px rgba(109, 255, 176, 0.7); }
.stats .good { color: #6dffb0; font-weight: 700; text-shadow: 0 0 12px rgba(109, 255, 176, 0.6); }
.heading.bad  { text-shadow: 0 0 22px rgba(255, 77, 109, 0.7); }

.howto {
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px 16px;
  max-width: 460px;
}
.howto h2 {
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 8px;
}
.howto ul { list-style: none; }
.howto li { margin: 5px 0; padding-left: 14px; position: relative; color: var(--dim); }
.howto li::before { content: "▸"; position: absolute; left: 0; color: var(--accent); }
.howto b { color: var(--ink); }

.settings { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; }

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(53, 224, 255, 0.08);
  border: 1px solid var(--line);
  color: var(--ink);
  border-radius: 999px;
  padding: 8px 14px;
  font-size: 13px;
  cursor: pointer;
}
.chip select {
  background: #101a30;
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 3px 6px;
  font: inherit;
}

#level-grid {
  display: grid;
  grid-template-columns: repeat(10, 1fr);
  gap: 6px;
  width: 100%;
  max-width: 460px;
}
#level-grid button {
  aspect-ratio: 1;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: rgba(53, 224, 255, 0.07);
  color: var(--ink);
  font: 700 14px/1 inherit;
  cursor: pointer;
}
#level-grid button:hover:not(.locked) { background: rgba(53, 224, 255, 0.25); }
#level-grid button.locked { opacity: 0.28; cursor: default; }
#level-grid button.current { border-color: var(--accent); box-shadow: 0 0 10px rgba(53, 224, 255, 0.5); }

button.big, button.mid {
  font: 800 16px/1 inherit;
  letter-spacing: 0.14em;
  border-radius: 999px;
  cursor: pointer;
  border: 1px solid transparent;
  transition: transform 0.08s ease, filter 0.08s ease;
}
button.big {
  padding: 15px 54px;
  font-size: 19px;
  color: #04121a;
  background: linear-gradient(180deg, #7df0ff, var(--accent));
  box-shadow: 0 0 30px rgba(53, 224, 255, 0.45);
}
button.mid {
  padding: 11px 30px;
  color: var(--ink);
  background: rgba(53, 224, 255, 0.08);
  border-color: var(--line);
}
button.big:hover, button.mid:hover { filter: brightness(1.15); transform: translateY(-1px); }
button.big:active, button.mid:active { transform: translateY(1px); }

.stats { color: var(--dim); font-size: 15px; text-align: center; line-height: 1.7; }
.stats b { color: var(--ink); font-size: 1.2em; }