:root {
  --bg-primary: #000000; /*pure black = transparent on additive display*/
  --bg-secondary: #0a0a0f;
  --bg-tertiary: #14141f;
  --bg-card: #1a1a2e;
  --text-primary: #ffffff;
  --text-secondary: #a0a0b0;
  --accent-primary: #00d4ff;
  --accent-secondary: #00ff88;
  --focus-ring: #00d4ff;
  --focus-glow: rgba(0, 212, 255, 0.4);
  --radius-md: 12px;
  --radius-lg: 16px;
}

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

html, body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  width: 600px;
  height: 600px;
  overflow: hidden;
}

#app { width: 100%; height: 100%; position: relative; }

.screen {
  width: 100%; height: 100%; position: absolute; top: 0; left: 0;
  display: flex; flex-direction: column;
  padding: 24px;
}
.screen.hidden { display: none; }

/* --- Centered layouts (intro / done) --- */
.center-col {
  flex: 1;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 20px; text-align: center;
}
.title { font-size: 40px; font-weight: 800; }
.subtitle { font-size: 18px; color: var(--text-secondary); max-width: 460px; line-height: 1.4; }

.cta {
  min-height: 88px; padding: 0 40px;
  background: var(--accent-primary); color: #04222b;
  border: 3px solid transparent; border-radius: var(--radius-lg);
  font-size: 22px; font-weight: 700; cursor: pointer;
  transition: transform 300ms cubic-bezier(0.6,0,0.4,1), box-shadow 300ms ease;
}
.cta:focus { outline: none; box-shadow: 0 0 30px var(--focus-glow); transform: scale(1.04); }

.check { font-size: 96px; color: var(--accent-secondary); }

/* --- Speaking orb --- */
.orb {
  position: relative;
  width: 150px; height: 150px;
  display: flex; align-items: center; justify-content: center;
}
.orb-core {
  width: 96px; height: 96px; border-radius: 50%;
  background: radial-gradient(circle at 35% 30%, #7ff0ff, var(--accent-primary) 60%, #0077aa 100%);
  box-shadow: 0 0 40px var(--focus-glow);
}
.orb::before, .orb::after {
  content: ''; position: absolute; border-radius: 50%;
  border: 3px solid var(--accent-primary); opacity: 0;
}
.orb.speaking::before { width: 120px; height: 120px; animation: ring 1.4s ease-out infinite; }
.orb.speaking::after { width: 120px; height: 120px; animation: ring 1.4s ease-out infinite 0.7s; }
@keyframes ring {
  0% { width: 96px; height: 96px; opacity: 0.7; }
  100% { width: 210px; height: 210px; opacity: 0; }
}
.orb.speaking .orb-core { animation: pulse 0.9s ease-in-out infinite; }
@keyframes pulse { 0%,100% { transform: scale(1); } 50% { transform: scale(1.08); } }

/* --- Tutorial layout --- */
.tut-top { flex: 0 0 auto; display: flex; justify-content: center; padding-top: 16px; }
.tut-mid {
  flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 22px; text-align: center;
}
.instruction { font-size: 32px; font-weight: 700; line-height: 1.3; max-width: 520px; }
.hint-chip {
  font-size: 20px; font-weight: 600; color: var(--accent-secondary);
  background: var(--bg-tertiary); padding: 12px 24px; border-radius: 24px;
}
.hint-chip.nudge { animation: nudge 0.4s ease; }
@keyframes nudge { 0%,100% { transform: translateX(0); } 25% { transform: translateX(-8px); } 75% { transform: translateX(8px); } }

/* --- Progress dots --- */
.dots { flex: 0 0 auto; display: flex; gap: 10px; justify-content: center; padding-bottom: 8px; }
.dot { width: 10px; height: 10px; border-radius: 50%; background: var(--bg-tertiary); transition: all 200ms ease; }
.dot.active { background: var(--accent-primary); width: 28px; border-radius: 5px; }
.dot.done { background: var(--accent-secondary); }

.hidden { display: none !important; }