:root {
  color-scheme: dark;
  --bg-top: #04070d;
  --bg-mid: #070d15;
  --bg-bottom: #020307;
  --ink: #eef3ff;
  --muted: rgba(210, 222, 240, 0.68);
}

* { box-sizing: border-box; }

html, body {
  width: 100%;
  height: 100%;
  margin: 0;
}

body {
  overflow: hidden;
  background:
    radial-gradient(circle at 20% 18%, rgba(100, 165, 255, 0.07), transparent 24%),
    radial-gradient(circle at 74% 78%, rgba(174, 220, 255, 0.05), transparent 22%),
    radial-gradient(circle at 58% 42%, rgba(255, 255, 255, 0.025), transparent 18%),
    linear-gradient(180deg, var(--bg-top) 0%, var(--bg-mid) 48%, var(--bg-bottom) 100%);
  font-family: "Manrope", "Hiragino Sans", "Yu Gothic", sans-serif;
}

#canvas {
  display: block;
  width: 100vw;
  height: 100vh;
  cursor: crosshair;
}

.hud {
  position: fixed;
  left: 24px;
  top: 24px;
  width: min(420px, calc(100vw - 48px));
  padding: 18px 20px;
  border-radius: 24px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(8, 12, 18, 0.26);
  backdrop-filter: blur(18px) saturate(125%);
  box-shadow: 0 22px 68px rgba(0, 0, 0, 0.28), inset 0 1px 0 rgba(255, 255, 255, 0.06);
}

.index, .meta, .hint, h1, p { margin: 0; }

.index {
  color: var(--muted);
  font-size: 12px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
}

h1 {
  margin-top: 10px;
  color: var(--ink);
  font-size: clamp(34px, 5.2vw, 64px);
  line-height: 0.96;
}

.meta {
  margin-top: 12px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.5;
}

.hint {
  margin-top: 14px;
  color: rgba(210, 222, 240, 0.8);
  font-size: 13px;
  line-height: 1.6;
}

.controls {
  margin-top: 14px;
  display: grid;
  gap: 12px;
}

.control {
  display: grid;
  gap: 8px;
}

.control span {
  color: rgba(210, 222, 240, 0.72);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.controls select {
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 14px;
  padding: 10px 14px;
  background: rgba(255, 255, 255, 0.06);
  color: var(--ink);
  font: inherit;
  cursor: pointer;
  outline: none;
}

.controls select:hover,
.controls select:focus {
  background: rgba(255, 255, 255, 0.1);
}

.toggle {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: rgba(224, 233, 247, 0.8);
  font-size: 13px;
}

.toggle input {
  width: 16px;
  height: 16px;
  accent-color: #c5d9ff;
}

.actions {
  display: flex;
}

.actions button {
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 999px;
  padding: 10px 16px;
  background: rgba(255, 255, 255, 0.06);
  color: var(--ink);
  font: inherit;
  cursor: pointer;
}

.actions button:hover,
.actions button:focus {
  background: rgba(255, 255, 255, 0.1);
}

.status {
  color: rgba(210, 222, 240, 0.72);
  font-size: 12px;
  line-height: 1.5;
}

.status.is-limit {
  color: rgba(255, 202, 214, 0.92);
}

@media (max-width: 720px) {
  .hud {
    left: 12px;
    right: 12px;
    top: 12px;
    width: auto;
    padding: 16px;
  }
}