:root {
  --bg: #0a0e1a;
  --panel: rgba(20, 26, 44, 0.74);
  --panel-solid: #141a2c;
  --ink: #eef1ff;
  --ink-dim: #9ba6c9;
  --bone: #ece3cf;     /* skeleton */
  --muscle: #d24a40;   /* muscle */
  --skin: #e7b48a;     /* skin */
  --accent: #5fd0c4;   /* teal medical accent */
  --accent-2: #8be0d8;
  --line: rgba(255, 255, 255, 0.12);
  --radius: 14px;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.45);
  --chip-bg: rgba(0, 0, 0, 0.25);       /* in-panel chip well (toggle/opt/etc.) */
  --chip-bg-2: rgba(0, 0, 0, 0.22);     /* secondary chip well (search/layer-row) */
  --chip-hover: rgba(0, 0, 0, 0.08);
  --on-accent: #06201d;                 /* readable text on the accent fill */
  --thumb: #fff;                        /* toggle/thumb knob fill (dark base) */
  --floor: #1b2440;                     /* subtle floor ring (canvas-painted) */
}
/* ===== 3-way theme (Light/Dark/System) — base :root above = native DARK. Opposite (light) WCAG-aware auto-generated (contrast-solving ink/accent vs worst-case surface). ===== */
:root[data-theme="light"]{
  --bg: #f4f4f6;
  --panel: #f6f6f7;
  --panel-solid: #f6f6f7;
  --ink: #002bf4;
  --ink-dim: #596ba5;
  --bone: #816933;
  --muscle: #c5392e;
  --skin: #a05a21;
  --accent: #23786f;
  --accent-2: #207870;
  --line: rgba(0,0,0,0.10);
  --chip-bg: #6c6c6c;
  --chip-bg-2: #6c6c6c;
  --chip-hover: #6c6c6c;
  --on-accent: #ffffff;
  --thumb: #NaNNaNNaN;
  --floor: #4f68b5;
}












* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; background: var(--bg); color: var(--ink);
  font-family: "Noto Sans KR", system-ui, -apple-system, "Apple SD Gothic Neo", sans-serif;
  -webkit-font-smoothing: antialiased; overflow: hidden; }

.app { position: fixed; inset: 0; }
#scene { position: absolute; inset: 0; width: 100%; height: 100%; display: block; touch-action: none; }

.hidden { display: none !important; }

/* overlays */
.overlay { position: absolute; inset: 0; display: flex; align-items: center; justify-content: center; z-index: 5; }
.loading { flex-direction: column; gap: 14px; color: var(--ink-dim); font-size: 14px; }
.spinner { width: 34px; height: 34px; border-radius: 50%; border: 3px solid var(--line); border-top-color: var(--accent); animation: spin 0.9s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

/* topbar + language switcher */
.topbar { position: absolute; top: max(10px, env(safe-area-inset-top)); right: max(12px, env(safe-area-inset-right)); z-index: 8; }
.topbar [data-i18n-switcher] select,
.topbar select { background: var(--panel); color: var(--ink); border: 1px solid var(--line); border-radius: 999px;
  padding: 6px 10px; font-size: 12px; backdrop-filter: blur(8px); }

/* title card */
.title-card { text-align: center; padding: 36px 30px; max-width: 440px; }
.logo { font-family: "Cabinet Grotesk", "Noto Sans KR", sans-serif; font-weight: 800; font-size: clamp(40px, 12vw, 76px);
  margin: 0 0 6px; letter-spacing: 1px;
  background: linear-gradient(120deg, var(--bone), var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.tagline { color: var(--ink-dim); margin: 0 0 26px; font-size: 15px; }

.btn { font: inherit; font-weight: 700; border: none; border-radius: 999px; padding: 13px 26px; cursor: pointer; transition: transform .15s, box-shadow .15s; }
.btn-primary { background: linear-gradient(120deg, var(--accent), var(--accent-2)); color: var(--on-accent); box-shadow: 0 8px 24px color-mix(in oklab, var(--accent) 38%, transparent); }
.btn-primary:hover { transform: translateY(-2px); }
.btn-primary:active { transform: translateY(0); }

/* layer panel — the main M1 control */
.layers { position: absolute; left: max(12px, env(safe-area-inset-left));
  top: 50%; transform: translateY(-50%); z-index: 8; display: flex; flex-direction: column; gap: 9px;
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px;
  backdrop-filter: blur(12px); box-shadow: var(--shadow); width: 196px; }
.layers-title { font-size: 11px; text-transform: uppercase; letter-spacing: 1.2px; color: var(--ink-dim); margin: 0 0 4px; }
.layer-row { display: flex; flex-direction: column; gap: 6px; padding: 8px 10px; border-radius: 10px; background: var(--chip-bg-2); }
.layer-head { display: flex; align-items: center; gap: 9px; }
.layer-dot { width: 12px; height: 12px; border-radius: 50%; flex: none; box-shadow: 0 0 0 2px rgba(255,255,255,0.08); }
.dot-skeleton { background: var(--bone); }
.dot-muscle { background: var(--muscle); }
.dot-skin { background: var(--skin); }
.layer-name { flex: 1; font-size: 13px; font-weight: 600; color: var(--ink); }
.layer-toggle { appearance: none; -webkit-appearance: none; width: 38px; height: 22px; border-radius: 999px;
  background: var(--chip-bg); position: relative; cursor: pointer; transition: background .15s; flex: none; border: 1px solid var(--line); }
.layer-toggle::after { content: ""; position: absolute; top: 3px; left: 3px; width: 16px; height: 16px; border-radius: 50%;
  background: var(--thumb); transition: transform .15s; box-shadow: 0 1px 2px rgba(0,0,0,0.3); }
.layer-toggle:checked { background: var(--accent); border-color: var(--accent); }
.layer-toggle:checked::after { transform: translateX(16px); }
.layer-slider { width: 100%; -webkit-appearance: none; appearance: none; height: 4px; border-radius: 999px;
  background: var(--chip-bg); outline: none; cursor: pointer; }
.layer-slider::-webkit-slider-thumb { -webkit-appearance: none; width: 14px; height: 14px; border-radius: 50%; background: var(--accent); border: 2px solid var(--thumb); }
.layer-slider::-moz-range-thumb { width: 14px; height: 14px; border-radius: 50%; background: var(--accent); border: 2px solid var(--thumb); }
.layer-row.is-off { opacity: 0.45; }

/* controls bar (reset view) */
.controls { position: absolute; right: max(14px, env(safe-area-inset-right));
  bottom: max(16px, env(safe-area-inset-bottom)); z-index: 10; display: flex; gap: 10px; align-items: center;
  background: var(--panel); border: 1px solid var(--line); border-radius: 999px; padding: 7px 10px; backdrop-filter: blur(10px); box-shadow: var(--shadow); }
.icon-btn { font-size: 15px; line-height: 1; color: var(--ink); background: var(--chip-bg); border: 1px solid var(--line);
  border-radius: 999px; width: 34px; height: 34px; cursor: pointer; display: inline-flex; align-items: center; justify-content: center; }
.icon-btn:hover { background: color-mix(in oklab, var(--accent) 18%, transparent); }

/* info panel */
.info { position: absolute; right: max(14px, env(safe-area-inset-right)); top: 54px; z-index: 9; width: min(290px, calc(100vw - 28px));
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px; backdrop-filter: blur(12px); box-shadow: var(--shadow); }
.info-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 10px; }
.info-head strong { font-family: "Cabinet Grotesk", "Noto Sans KR", sans-serif; font-size: 19px; color: var(--ink); }
.info-close { background: none; border: none; color: var(--ink-dim); font-size: 16px; cursor: pointer; line-height: 1; padding: 2px 6px; border-radius: 8px; }
.info-close:hover { background: var(--chip-hover); color: var(--ink); }
.info-meta { display: flex; gap: 6px; align-items: center; margin: 0 0 10px; font-size: 11px; }
.info-meta .tag { display: inline-flex; align-items: center; gap: 5px; padding: 3px 9px; border-radius: 999px;
  background: var(--chip-bg); color: var(--ink-dim); }
.info-fact { margin: 0; font-size: 13px; line-height: 1.55; color: var(--ink); border-top: 1px solid var(--line); padding-top: 10px; }

.hint { position: absolute; left: 50%; transform: translateX(-50%); top: max(10px, env(safe-area-inset-top));
  z-index: 4; margin: 0; font-size: 11.5px; color: var(--ink-dim); opacity: 0.8; text-align: center; pointer-events: none;
  background: var(--panel); border: 1px solid var(--line); border-radius: 999px; padding: 5px 14px; backdrop-filter: blur(8px); white-space: nowrap; }

.foot { position: absolute; left: 50%; transform: translateX(-50%); bottom: max(16px, env(safe-area-inset-bottom));
  z-index: 4; margin: 0; font-size: 11px; color: var(--ink-dim); opacity: 0.7; text-align: center; pointer-events: none;
  white-space: nowrap; padding-right: 220px; }

/* V2: label-mode toggle active state */
.icon-btn.toggle.is-on { background: var(--accent); color: var(--on-accent); border-color: var(--accent); }

/* V2: search panel */
.search { position: absolute; left: max(12px, env(safe-area-inset-left)); top: max(12px, env(safe-area-inset-top));
  z-index: 8; display: flex; flex-direction: column; gap: 6px; width: min(196px, calc(100vw - 24px));
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 10px 12px;
  backdrop-filter: blur(12px); box-shadow: var(--shadow); }
.search-label { font-size: 11px; text-transform: uppercase; letter-spacing: 1.2px; color: var(--ink-dim); }
.search-input { font: inherit; font-size: 13px; color: var(--ink); background: var(--chip-bg-2); border: 1px solid var(--line);
  border-radius: 10px; padding: 7px 10px; outline: none; }
.search-input:focus { border-color: var(--accent); }
.search-input::placeholder { color: var(--ink-dim); opacity: 0.8; }
.search-status { margin: 0; font-size: 11px; color: var(--muscle); }
.search-status.hidden { display: none; }

/* V2: floating part labels (projected HTML over the canvas) */
.labels-layer { position: absolute; inset: 0; z-index: 6; pointer-events: none; display: none; }
.labels-layer.is-on { display: block; }
.part-label { position: absolute; top: 0; left: 0; transform: translate(-50%, -50%);
  display: inline-flex; align-items: center; gap: 5px; padding: 3px 9px 3px 7px;
  background: var(--panel-solid); color: var(--ink); border: 1px solid var(--line); border-radius: 999px;
  font-size: 11px; font-weight: 600; white-space: nowrap; box-shadow: 0 2px 8px rgba(0,0,0,0.35);
  opacity: 0.92; will-change: left, top; }
.part-label.is-behind { display: none; }
.part-label-dot { width: 7px; height: 7px; border-radius: 50%; flex: none; background: var(--accent); }
.part-label[data-layer="skeleton"] .part-label-dot { background: var(--bone); }
.part-label[data-layer="muscle"]   .part-label-dot { background: var(--muscle); }
.part-label[data-layer="skin"]     .part-label-dot { background: var(--skin); }
@media (prefers-reduced-motion: reduce) { .part-label { will-change: auto; } }

@media (max-width: 720px) {
  .layers { top: auto; bottom: 64px; transform: none; left: 50%; translate: -50% 0; width: min(340px, calc(100vw - 24px));
    flex-direction: row; flex-wrap: wrap; padding: 10px; gap: 6px; }
  .layers-title { width: 100%; text-align: center; margin-bottom: 2px; }
  .layer-row { flex: 1 1 100px; }
  .foot { display: none; }
}
/* FAB/mobile collision: the GitHub Sponsors .pmp-fab is fixed bottom-right
   (~34px tall). Reserve a right gutter on small screens so the .controls HUD
   (reset / label / quiz) clears it and stays tappable. */
@media (max-width: 540px) {
  .controls {
    right: max(56px, calc(env(safe-area-inset-right) + 50px));
    bottom: max(16px, env(safe-area-inset-bottom));
  }
  .quiz {
    /* keep the centered quiz panel clear of the FAB band on the right */
    max-width: calc(100vw - 70px);
  }
}
@media (max-width: 480px) {
  .hint { font-size: 12px; padding: 4px 10px; }
}
@media (prefers-reduced-motion: reduce) { .spinner, .btn-primary { animation: none; transition: none; } }

/* V3: quiz mode */
.quiz { position: absolute; left: 50%; transform: translateX(-50%);
  bottom: max(16px, env(safe-area-inset-bottom)); z-index: 9;
  width: min(380px, calc(100vw - 28px));
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 14px 16px; backdrop-filter: blur(12px); box-shadow: var(--shadow); }
.quiz-head { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.quiz-title { font-family: "Cabinet Grotesk", "Noto Sans KR", sans-serif; font-size: 17px; color: var(--ink); flex: 1; }
.quiz-score { font-size: 12px; font-weight: 600; color: var(--ink-dim);
  background: var(--chip-bg); padding: 3px 9px; border-radius: 999px; }
.quiz-prompt { margin: 0 0 10px; font-size: 13px; color: var(--ink); }
.quiz-options { display: flex; flex-direction: column; gap: 8px; }
.quiz-opt { font: inherit; font-size: 13px; font-weight: 600; text-align: left;
  color: var(--ink); background: var(--chip-bg-2); border: 1px solid var(--line);
  border-radius: 10px; padding: 9px 12px; cursor: pointer; transition: background .15s, transform .1s; }
.quiz-opt:hover:not(:disabled) { background: color-mix(in oklab, var(--accent) 18%, transparent); }
.quiz-opt:active:not(:disabled) { transform: translateY(1px); }
.quiz-opt.is-correct { background: color-mix(in oklab, var(--accent) 30%, transparent); border-color: var(--accent); color: var(--accent-2); }
.quiz-opt.is-wrong { background: color-mix(in oklab, var(--muscle) 28%, transparent); border-color: var(--muscle); color: var(--muscle); }
.quiz-feedback { margin: 10px 0 0; font-size: 12.5px; font-weight: 600; min-height: 1em; }
.quiz-feedback.is-correct { color: var(--accent-2); }
.quiz-feedback.is-wrong { color: var(--muscle); }
.quiz-next { margin-top: 12px; padding: 9px 18px; font-size: 13px; }
.icon-btn.toggle.is-on[aria-label]:hover { } /* placeholder kept minimal */
@media (max-width: 480px) {
  .quiz { width: calc(100vw - 20px); padding: 12px 13px; }
  .quiz-opt { padding: 10px 11px; }
}
@media (prefers-reduced-motion: reduce) { .quiz-opt { transition: none; } }