:root {
  color-scheme: dark;
  --cyan: #7ef6ff;
  --mint: #9dffc8;
  --bg: #04060f;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--bg);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

canvas {
  display: block;
}

.overlay {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  place-items: center;
  background:
    radial-gradient(ellipse at 50% 0%, rgba(70, 40, 140, 0.35), transparent 55%),
    linear-gradient(180deg, rgba(4, 8, 24, 0.28), rgba(2, 4, 16, 0.62));
  transition: opacity 0.35s ease, visibility 0.35s ease;
}

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

.panel {
  text-align: center;
  padding: 2.4rem 2.2rem 2rem;
  min-width: min(86vw, 420px);
  border: 1px solid rgba(126, 246, 255, 0.28);
  border-radius: 18px;
  background: rgba(6, 10, 28, 0.55);
  box-shadow:
    0 0 40px rgba(80, 220, 255, 0.12),
    inset 0 0 40px rgba(80, 255, 200, 0.05);
  backdrop-filter: blur(10px);
}

.kicker {
  margin: 0 0 0.6rem;
  letter-spacing: 0.42em;
  font-size: 0.72rem;
  color: var(--mint);
}

h1 {
  margin: 0;
  font-size: clamp(1.55rem, 5.2vw, 2.35rem);
  font-weight: 700;
  letter-spacing: 0.06em;
  color: #f4fbff;
  text-shadow: 0 0 28px rgba(90, 230, 255, 0.55);
}

.overlay.is-win h1 {
  font-size: clamp(2.1rem, 8vw, 3.4rem);
  color: #1a6b32;
  text-shadow: 0 0 28px rgba(26, 107, 50, 0.55);
}

.overlay.is-dead h1 {
  font-size: clamp(2.1rem, 8vw, 3.4rem);
  color: #a8101c;
  text-shadow: 0 0 28px rgba(120, 8, 18, 0.75);
}

.overlay.is-win .tagline {
  color: #247a3e;
  font-size: 1.28rem;
  font-weight: 600;
}

.overlay.is-dead .tagline {
  min-height: 0;
  margin: 0.4rem 0 1.6rem;
}

.tagline {
  margin: 0.7rem 0 1.6rem;
  color: rgba(210, 230, 255, 0.78);
  letter-spacing: 0.12em;
}

#btn-start {
  appearance: none;
  border: 0;
  cursor: pointer;
  min-width: 240px;
  min-height: 64px;
  padding: 0.9rem 2.2rem;
  border-radius: 999px;
  font-size: 1.25rem;
  letter-spacing: 0.28em;
  color: #041018;
  background: linear-gradient(135deg, #b8ffe0, #7ef6ff 55%, #7aa7ff);
  box-shadow: 0 0 28px rgba(126, 246, 255, 0.45);
}

#btn-start:disabled {
  cursor: not-allowed;
  opacity: 0.55;
  box-shadow: none;
}

.status {
  min-height: 1.4em;
  margin: 1rem 0 0;
  color: #ffd1dc;
  font-size: 0.95rem;
}

.hint {
  margin: 0.4rem 0 0;
  color: rgba(180, 210, 230, 0.65);
  font-size: 0.85rem;
}