@property --hue-a { syntax: "<color>"; inherits: true; initial-value: #5b8cff; }
@property --hue-b { syntax: "<color>"; inherits: true; initial-value: #6d4aff; }
@property --hue-c { syntax: "<color>"; inherits: true; initial-value: #4ade80; }

:root {
  color-scheme: dark;
  --bg: #050507;
  --fg: #f5f5f7;
  --dim: #8e939e;
  --soft: #b6b7ba;
  --hair: rgb(255 255 255 / 0.14);
  --faint: rgb(255 255 255 / 0.06);
  --glass: rgb(255 255 255 / 0.04);
  --glass-strong: rgb(18 20 30 / 0.72);
  --accent: #5b8cff;
  --violet: #8b5cf6;
  --mint: #4ade80;
  --gold: #fac86e;
  --rose: #ff7ab6;
  --sky: #78b4ff;
  --danger: #ff6b6b;
  --sans: "Geist", system-ui, sans-serif;
  --mono: "Geist Mono", ui-monospace, monospace;
  --out: cubic-bezier(0.16, 1, 0.3, 1);
  --radius: 18px;
  --pill: 999px;
  --orb-size: 220px;
  --orb-size-working: 112px;
  --panel-width: 360px;
  --board-height: min(50vh, 520px);
  --dock-space: 112px;
  --gutter: 16px;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  margin: 0;
  min-height: 100vh;
  font: 400 15px/1.5 var(--sans);
  color: var(--fg);
  background:
    radial-gradient(1100px 700px at 50% -12%, rgb(91 140 255 / 0.16), transparent 60%),
    radial-gradient(900px 640px at 88% 112%, rgb(139 92 246 / 0.13), transparent 60%),
    radial-gradient(700px 520px at -6% 82%, rgb(74 222 128 / 0.05), transparent 60%),
    var(--bg);
  background-attachment: fixed;
  overflow-x: hidden;
}

#cosmos { position: fixed; inset: 0; width: 100%; height: 100%; pointer-events: none; }

button, input, textarea { font: inherit; color: inherit; }
button {
  background: var(--glass);
  border: 1px solid var(--hair);
  border-radius: var(--pill);
  padding: 8px 14px;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s, transform 0.25s var(--out), opacity 0.2s;
}
button:hover:not(:disabled) { background: rgb(255 255 255 / 0.09); }
button:active:not(:disabled) { transform: scale(0.97); }
button:disabled { opacity: 0.4; cursor: default; }
button.on { background: rgb(91 140 255 / 0.18); border-color: rgb(91 140 255 / 0.6); }
button.ghost { background: transparent; border-color: transparent; color: var(--soft); }
button.ghost:hover { color: var(--fg); background: var(--glass); }
button.icon { display: inline-grid; place-items: center; padding: 7px; }
button.icon svg, .mic svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
#voice[aria-pressed="true"] .mute, #voice[aria-pressed="false"] .waves { display: none; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

textarea, input[type="text"] {
  width: 100%;
  background: var(--glass);
  border: 1px solid var(--hair);
  border-radius: 14px;
  padding: 12px 14px;
  resize: vertical;
}
textarea::placeholder, input::placeholder { color: var(--dim); }

.bar {
  position: fixed; inset: 0 0 auto; z-index: 3;
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 20px;
  background: linear-gradient(var(--bg), transparent);
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 500; letter-spacing: 0.02em; }
.brand-mark { width: 14px; height: 14px; border-radius: 50%; background: radial-gradient(circle at 35% 30%, #fff, var(--accent) 45%, var(--violet)); box-shadow: 0 0 14px var(--accent); }
.bar-actions { display: flex; align-items: center; gap: 6px; }
.timer { font: 500 13px var(--mono); color: var(--dim); font-variant-numeric: tabular-nums; margin-right: 6px; }

main {
  position: relative; z-index: 1;
  max-width: 1040px; margin: 0 auto;
  padding: 72px var(--gutter) var(--dock-space);
  display: flex; flex-direction: column; align-items: center; gap: 18px;
  transition: margin 0.5s var(--out);
}
body.panel-open main { margin-right: calc(var(--panel-width) + 2 * var(--gutter)); }

.presence { display: flex; flex-direction: column; align-items: center; gap: 10px; text-align: center; width: 100%; }
.state { margin: 4px 0 0; font: 500 11px/1 var(--mono); letter-spacing: 0.18em; text-transform: uppercase; color: var(--dim); }
.caption {
  margin: 0; max-width: 760px; min-height: 1.45em;
  font-size: clamp(18px, 2.1vw, 23px); font-weight: 300; line-height: 1.45;
  text-wrap: balance; animation: rise 0.6s var(--out);
}
.caption.student { color: var(--dim); font-style: italic; }
@keyframes rise { from { opacity: 0; transform: translateY(6px); } }

.orb {
  --level: 0;
  --spin: 16s;
  --orbit: 26s;
  position: relative;
  width: var(--orb-size); aspect-ratio: 1;
  margin-top: 8px;
  perspective: 600px;
  transform: scale(calc(1 + var(--level) * 0.12));
  transition: width 0.8s var(--out), --hue-a 1.2s, --hue-b 1.2s, --hue-c 1.2s;
  animation: breathe 6s ease-in-out infinite;
}
body.working .orb { --orb-size: var(--orb-size-working); }
.orb .core {
  position: absolute; inset: 0; border-radius: 50%; overflow: hidden;
  background: radial-gradient(circle at 34% 28%, #fff 0 5%, color-mix(in oklab, var(--hue-a) 55%, white) 15%, var(--hue-a) 38%, var(--hue-b) 66%, #0b0820 100%);
  box-shadow:
    0 0 calc(30px + var(--level) * 90px) color-mix(in oklab, var(--hue-a) 70%, transparent),
    0 0 140px color-mix(in oklab, var(--hue-b) 45%, transparent),
    inset 0 0 30px rgb(255 255 255 / 0.25);
}
.orb .core::before {
  content: ""; position: absolute; inset: -35%;
  background: conic-gradient(from 0deg, transparent, color-mix(in oklab, var(--hue-c) 75%, transparent), transparent 30%, color-mix(in oklab, var(--hue-b) 80%, transparent) 55%, transparent 72%);
  filter: blur(12px); mix-blend-mode: screen;
  animation: spin var(--spin) linear infinite;
}
.orb .core::after {
  content: ""; position: absolute; inset: 0; border-radius: 50%;
  background: radial-gradient(circle at 30% 24%, rgb(255 255 255 / 0.55), transparent 28%);
}
.orb .halo {
  position: absolute; inset: -70%; border-radius: 50%;
  background: radial-gradient(circle, color-mix(in oklab, var(--hue-a) 28%, transparent) 0%, transparent 62%);
  filter: blur(18px); opacity: calc(0.55 + var(--level) * 0.45);
}
.orb .ring {
  position: absolute; inset: -16%; border-radius: 50%;
  border: 1px solid rgb(255 255 255 / 0.16);
  transform: rotateX(72deg) rotateZ(0deg);
  animation: orbit var(--orbit) linear infinite;
}
.orb .ring::after {
  content: ""; position: absolute; top: -3px; left: 50%; width: 6px; height: 6px; border-radius: 50%;
  background: #fff; box-shadow: 0 0 12px var(--hue-a), 0 0 4px #fff;
}
.orb .ring.outer { inset: -34%; opacity: 0.55; animation-duration: calc(var(--orbit) * 1.7); animation-direction: reverse; }
@keyframes spin { to { rotate: 360deg; } }
@keyframes orbit { to { transform: rotateX(72deg) rotateZ(360deg); } }
@keyframes breathe { 50% { translate: 0 -4px; } }

.orb[data-state="idle"] { --hue-a: #4f63a8; --hue-b: #2b2160; --hue-c: #5b8cff; --spin: 30s; }
.orb[data-state="preparing"] { --hue-a: #6f7dff; --hue-b: #8b5cf6; --hue-c: #78b4ff; --spin: 6s; --orbit: 10s; }
.orb[data-state="watching"] { --hue-a: #5b8cff; --hue-b: #6d4aff; --hue-c: #4ade80; }
.orb[data-state="thinking"] { --hue-a: #a78bfa; --hue-b: #ec4899; --hue-c: #5b8cff; --spin: 2.5s; --orbit: 6s; }
.orb[data-state="speaking"] { --hue-a: #fac86e; --hue-b: #ff7ab6; --hue-c: #fff3c4; --spin: 8s; }
.orb[data-state="listening"] { --hue-a: #78b4ff; --hue-b: #22d3ee; --hue-c: #8ce6aa; --spin: 9s; }
.orb[data-state="solved"] { --hue-a: #4ade80; --hue-b: #22c3a6; --hue-c: #fac86e; --spin: 12s; }

.setup { width: min(640px, 100%); display: flex; flex-direction: column; align-items: center; gap: 16px; text-align: center; }
.setup h1 { margin: 6px 0 0; font-size: clamp(28px, 4.4vw, 44px); font-weight: 500; letter-spacing: -0.02em; }
.chips { display: flex; flex-wrap: wrap; justify-content: center; gap: 8px; }
.chips button { font-size: 13px; color: var(--soft); }
.primary {
  padding: 12px 34px; border: none; font-weight: 500; font-size: 16px;
  background: linear-gradient(135deg, var(--accent), var(--violet));
  box-shadow: 0 10px 40px rgb(91 140 255 / 0.35);
}
.primary:hover:not(:disabled) { background: linear-gradient(135deg, #6d9bff, #9a70ff); }
.fine { margin: 0; color: var(--dim); font-size: 13px; }

.work { width: 100%; display: flex; flex-direction: column; gap: 12px; }
.problem { margin: 6px 0 2px; text-align: center; font-size: clamp(18px, 2.2vw, 24px); font-weight: 500; white-space: pre-wrap; }
.board {
  position: relative; height: var(--board-height);
  border: 1px solid var(--hair); border-radius: var(--radius);
  background: rgb(255 255 255 / 0.022) radial-gradient(rgb(255 255 255 / 0.07) 1px, transparent 1px) 0 0 / 28px 28px;
  box-shadow: inset 0 1px 0 rgb(255 255 255 / 0.06), 0 30px 80px rgb(0 0 0 / 0.35);
  backdrop-filter: blur(4px);
  overflow: hidden;
}
#pad { position: absolute; inset: 0; width: 100%; height: 100%; touch-action: none; cursor: crosshair; }
.board-hint { position: absolute; left: 22px; top: 18px; margin: 0; color: var(--dim); pointer-events: none; transition: opacity 0.4s; }
.board-tools {
  position: absolute; right: 10px; top: 10px; display: flex; gap: 4px; padding: 4px;
  border: 1px solid var(--hair); border-radius: var(--pill); background: var(--glass-strong); backdrop-filter: blur(12px);
}
.board-tools button { padding: 5px 12px; font-size: 13px; border-color: transparent; }
#typed { font-family: var(--mono); font-size: 14px; min-height: 52px; }

.dock {
  position: fixed; z-index: 3; left: 50%; bottom: 20px; translate: -50% 0;
  width: min(820px, calc(100% - 2 * var(--gutter)));
  display: flex; align-items: center; gap: 8px; padding: 8px;
  border: 1px solid var(--hair); border-radius: var(--pill);
  background: var(--glass-strong); backdrop-filter: blur(18px) saturate(140%);
  box-shadow: 0 20px 60px rgb(0 0 0 / 0.5);
  transition: translate 0.5s var(--out);
}
body.panel-open .dock { translate: calc(-50% - (var(--panel-width) + var(--gutter)) / 2) 0; }
.dock input { flex: 1; min-width: 0; border: none; background: transparent; padding: 10px 6px; }
.dock input:focus-visible { outline: none; }
.dock .divider { width: 1px; height: 26px; background: var(--hair); }
.dock .chip { font-size: 13px; padding: 8px 12px; white-space: nowrap; }
.send { color: var(--soft); }
.mic {
  flex: none; width: 46px; height: 46px; padding: 0; display: grid; place-items: center;
  border: none; color: #fff;
  background: radial-gradient(circle at 35% 30%, #8fb0ff, var(--accent) 55%, var(--violet));
  box-shadow: 0 0 22px rgb(91 140 255 / 0.45);
}
.mic.rec { background: radial-gradient(circle at 35% 30%, #ffb4b4, var(--danger) 60%, #b4235a); box-shadow: 0 0 0 calc(4px + var(--mic-level, 0) * 18px) rgb(255 107 107 / 0.25), 0 0 26px rgb(255 107 107 / 0.6); }
.listening { display: none; align-items: center; gap: 4px; flex: 1; color: var(--sky); font: 500 12px var(--mono); letter-spacing: 0.16em; text-transform: uppercase; }
.listening span { margin-right: 8px; }
.listening i { width: 4px; height: calc(6px + var(--mic-level, 0) * 22px); border-radius: 2px; background: var(--sky); transition: height 0.08s; }
.listening i:nth-child(odd) { height: calc(4px + var(--mic-level, 0) * 14px); }
.dock.is-listening .listening { display: flex; }
.dock.is-listening input, .dock.is-listening .send { display: none; }

.panel {
  position: fixed; z-index: 2; top: 64px; right: var(--gutter); bottom: 20px; width: var(--panel-width);
  display: flex; flex-direction: column; gap: 18px; padding: 16px; overflow-y: auto;
  border: 1px solid var(--hair); border-radius: var(--radius);
  background: var(--glass-strong); backdrop-filter: blur(18px);
}
.panel h3, .panel summary { margin: 0 0 10px; font: 500 11px var(--mono); letter-spacing: 0.16em; text-transform: uppercase; color: var(--dim); cursor: default; }
.panel summary { cursor: pointer; }
.chat { display: flex; flex-direction: column; gap: 8px; }
.msg { max-width: 92%; padding: 8px 12px; border-radius: 14px; font-size: 14px; white-space: pre-wrap; }
.msg.from-tutor { align-self: flex-start; background: rgb(91 140 255 / 0.14); border: 1px solid rgb(91 140 255 / 0.25); border-bottom-left-radius: 4px; }
.msg.from-student { align-self: flex-end; background: var(--faint); border: 1px solid var(--hair); border-bottom-right-radius: 4px; }
.msg.from-system { align-self: center; color: var(--dim); font-size: 12px; text-align: center; }
.msg .meta { display: block; margin-top: 2px; font: 11px var(--mono); color: var(--dim); }
.summary { display: grid; grid-template-columns: auto 1fr; gap: 6px 14px; margin: 0; font-size: 13px; }
.summary dt { color: var(--dim); }
.summary dd { margin: 0; }
.trace { width: 100%; border-collapse: collapse; font: 11px/1.4 var(--mono); color: var(--soft); }
.trace th, .trace td { padding: 4px; border-bottom: 1px solid var(--faint); text-align: left; vertical-align: top; }
.trace tr.fired td { color: var(--gold); }
.trace tr.skipped td { color: var(--dim); }

@media (max-width: 1279px) {
  body.panel-open main { margin-right: auto; }
  body.panel-open .dock { translate: -50% 0; }
  .panel { top: auto; height: 60vh; left: var(--gutter); width: auto; bottom: 96px; }
}
@media (max-width: 720px) {
  :root { --orb-size: 160px; --orb-size-working: 84px; --board-height: 46vh; --dock-space: 150px; }
  .dock { flex-wrap: wrap; border-radius: 26px; }
  .dock .divider { display: none; }
  .dock .chip { flex: 1; }
  .board-tools button { padding: 5px 9px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}