:root {
  --bg: #0b1220;
  --fg: #e8eef8;
  --muted: #93a4bd;
  --accent: #3dd6c6;
  --danger: #ff6b6b;
  --ok: #5ee09a;
  --panel: rgba(16, 28, 48, 0.88);
  --line: rgba(255, 255, 255, 0.12);
  font-family: "Segoe UI", "Noto Sans TC", "Microsoft JhengHei", sans-serif;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  background: radial-gradient(1200px 800px at 20% -10%, #1a2b4a 0%, var(--bg) 55%);
  color: var(--fg);
}

a {
  color: var(--accent);
}

.wrap {
  max-width: 720px;
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}

h1 {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  margin: 0 0 0.5rem;
  letter-spacing: 0.02em;
}

.lead {
  color: var(--muted);
  line-height: 1.55;
  margin: 0 0 1.5rem;
}

.actions {
  display: grid;
  gap: 0.85rem;
}

.btn {
  appearance: none;
  border: 1px solid var(--line);
  background: linear-gradient(180deg, #1c2f4d, #14233c);
  color: var(--fg);
  border-radius: 12px;
  padding: 0.95rem 1.1rem;
  font-size: 1.05rem;
  font-weight: 600;
  text-decoration: none;
  text-align: center;
  cursor: pointer;
}

.btn:active {
  transform: translateY(1px);
}

.btn.primary {
  border-color: rgba(61, 214, 198, 0.45);
  box-shadow: 0 0 0 1px rgba(61, 214, 198, 0.15) inset;
}

.btn.ghost {
  background: transparent;
}

.hint {
  margin-top: 1.5rem;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--panel);
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.5;
}

.hint code {
  color: var(--accent);
  font-size: 0.86em;
}

/* Display */
.display-body {
  overflow: hidden;
  height: 100vh;
  background: #070b14;
}

#stage {
  display: block;
  width: 100vw;
  height: 100vh;
  touch-action: none;
}

.hud {
  position: fixed;
  left: 12px;
  top: 12px;
  z-index: 2;
  min-width: 220px;
  max-width: min(92vw, 360px);
  padding: 0.75rem 0.9rem;
  border-radius: 12px;
  border: 1px solid var(--line);
  background: var(--panel);
  backdrop-filter: blur(8px);
  font-size: 0.86rem;
  line-height: 1.45;
}

.hud .row {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
}

.hud .label {
  color: var(--muted);
}

.hud .ok {
  color: var(--ok);
}

.hud .bad {
  color: var(--danger);
}

#hud-clear {
  margin-top: 0.45rem;
  padding: 0.35rem 0.6rem;
  font-size: 0.8rem;
}

.hud .url {
  margin-top: 0.55rem;
  word-break: break-all;
  color: var(--accent);
  font-size: 0.78rem;
}

/* Controller */
.controller-body {
  min-height: 100vh;
}

.panel {
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--panel);
  padding: 1rem;
  margin-bottom: 1rem;
}

.status-line {
  font-size: 0.95rem;
  margin: 0 0 0.75rem;
}

#pad {
  width: 100%;
  aspect-ratio: 1;
  max-height: 55vh;
  border-radius: 16px;
  border: 1px dashed rgba(61, 214, 198, 0.35);
  background:
    radial-gradient(circle at 50% 50%, rgba(61, 214, 198, 0.08), transparent 55%),
    #0a1424;
  position: relative;
  touch-action: none;
  overflow: hidden;
}

#padDot {
  position: absolute;
  width: 28px;
  height: 28px;
  margin: -14px 0 0 -14px;
  border-radius: 50%;
  background: rgba(61, 214, 198, 0.85);
  box-shadow: 0 0 18px rgba(61, 214, 198, 0.45);
  left: 50%;
  top: 50%;
  pointer-events: none;
}

.btn-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-top: 0.85rem;
}

.err {
  color: var(--danger);
  margin: 0.5rem 0 0;
  font-size: 0.9rem;
}

.mode-row {
  margin-bottom: 0.85rem;
  grid-template-columns: 1fr 1fr 1fr;
}

#cam-box video {
  width: 100%;
  max-height: 28vh;
  margin-top: 0.85rem;
  border-radius: 12px;
  background: #000;
  object-fit: cover;
}

.gain {
  display: grid;
  gap: 0.35rem;
  margin-top: 0.75rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.flow {
  margin: 0.45rem 0 0;
  color: var(--muted);
  font-size: 0.86rem;
}