:root{
  --bg:#0e1116; --panel:#161b22; --ink:#e6edf3; --muted:#8b949e;
  --accent:#3b82f6; --line:#30363d; --ok:#22c55e; --warn:#f59e0b;
  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{background:var(--bg);color:var(--ink);font-family:var(--font);overflow:hidden}
#app{height:100vh;width:100vw}

.screen{display:none;height:100vh;width:100vw;align-items:center;justify-content:center;padding:24px}
.screen.active{display:flex}

.card{background:var(--panel);border:1px solid var(--line);border-radius:14px;
  padding:32px;max-width:560px;width:100%}
.card h1{font-size:24px;margin-bottom:16px}
.card h2{font-size:20px;margin-bottom:16px}
.card h3{font-size:14px;color:var(--muted);margin-bottom:10px;text-transform:uppercase;letter-spacing:.05em}
.consent-text p{color:var(--muted);font-size:14px;line-height:1.6;margin-bottom:10px}

.checkbox{display:flex;align-items:center;gap:10px;margin:18px 0;font-size:15px;cursor:pointer}
.checkbox input{width:18px;height:18px;accent-color:var(--accent)}

.researcher-box{border:1px dashed var(--line);border-radius:10px;padding:16px;margin:18px 0}
.researcher-box label{display:flex;flex-direction:column;gap:6px;font-size:13px;
  color:var(--muted);margin-bottom:12px}
.researcher-box label:last-child{margin-bottom:0}
.form-block{display:flex;flex-direction:column;gap:12px;margin:14px 0}
.form-block label{display:flex;flex-direction:column;gap:6px;font-size:13px;color:var(--muted)}
.err-line{color:#f87171;font-size:13px;min-height:18px;margin-top:8px}
input,select{background:var(--bg);border:1px solid var(--line);color:var(--ink);
  padding:9px 10px;border-radius:8px;font-size:14px;font-family:var(--font)}

button{cursor:pointer;border:1px solid var(--line);background:transparent;color:var(--ink);
  padding:11px 20px;border-radius:9px;font-size:14px;font-family:var(--font)}
button.primary{background:var(--accent);border-color:var(--accent);color:#fff}
button:disabled{opacity:.45;cursor:not-allowed}
.btn-start, #btn-start{width:100%;margin-top:6px}
.hint{color:var(--muted);font-size:12px;margin-top:12px}
code{background:var(--bg);padding:1px 6px;border-radius:5px;font-size:12px}

#cam-preview{width:100%;border-radius:10px;background:#000;aspect-ratio:4/3;
  margin:14px 0;transform:scaleX(-1)}
#cam-status{font-size:14px;color:var(--muted);margin-bottom:14px}

#screen-baseline{padding:0;position:relative;background:#000}
#baseline-canvas,#baseline-video{position:absolute;inset:0;width:100%;height:100%;object-fit:cover}
.baseline-overlay{position:absolute;bottom:24px;left:0;right:0;text-align:center;
  font-size:13px;color:rgba(255,255,255,.55)}

.block-wrap,.q-wrap{max-width:760px;width:100%}
.block-meta{display:flex;justify-content:space-between;color:var(--muted);
  font-size:13px;margin-bottom:24px}
.fact-box{font-size:24px;line-height:1.5;text-align:center;min-height:160px;
  display:flex;align-items:center;justify-content:center;padding:0 20px}
.progress{height:3px;background:var(--line);border-radius:2px;margin-top:32px;overflow:hidden}
#block-progress{height:100%;background:var(--accent);width:0;transition:width .25s linear}

.question-text{font-size:20px;line-height:1.5;margin-bottom:28px;text-align:center}
.answers{display:flex;flex-direction:column;gap:12px}
.answer-btn{text-align:left;padding:16px 18px;font-size:16px}
.answer-btn:hover{border-color:var(--accent)}
.answer-no{margin-top:8px;border-style:dashed;color:var(--muted);font-style:italic}
.answer-no:hover{border-color:var(--warn);color:var(--warn)}

.summary{font-size:13px;color:var(--muted);line-height:1.7;margin:16px 0;
  background:var(--bg);border:1px solid var(--line);border-radius:8px;padding:14px;
  max-height:260px;overflow:auto;white-space:pre-wrap;font-family:ui-monospace,monospace}
.export-row{display:flex;gap:12px}

.guard-overlay{display:none;position:fixed;inset:0;background:rgba(8,10,14,.97);
  z-index:999;flex-direction:column;align-items:center;justify-content:center;gap:20px;
  text-align:center;padding:24px}
.guard-overlay.show{display:flex}
#guard-msg{font-size:18px;color:var(--warn);max-width:420px;line-height:1.5}

/* ---- always-visible corner camera widget ---- */
#cam-corner{position:fixed;bottom:14px;right:14px;width:200px;
  border:1px solid var(--line);border-radius:10px;overflow:hidden;background:#000;
  z-index:9000;box-shadow:0 6px 20px rgba(0,0,0,.4);
  transition:opacity .2s,border-color .2s}
#cam-corner.hidden{display:none}
#cam-corner-video,#cam-corner-mask{position:absolute;inset:0;width:100%;height:150px;
  object-fit:cover;transform:scaleX(-1)}
#cam-corner-mask{background:transparent;pointer-events:none}
#cam-corner{padding-bottom:28px;height:178px}
.cam-corner-info{position:absolute;bottom:0;left:0;right:0;height:28px;
  background:rgba(0,0,0,.7);color:#e6edf3;font-size:11px;
  display:flex;align-items:center;gap:8px;padding:0 8px;font-family:ui-monospace,monospace}
.cam-corner-info .dot{width:8px;height:8px;border-radius:50%;background:#6b7280;
  transition:background .15s}
.cam-corner-info .dot.ok{background:var(--ok)}
.cam-corner-info .dot.blink{background:#fbbf24}
.cam-corner-info .dot.lost{background:#ef4444}
.cam-corner-info .counter{margin-left:auto}
#cam-corner.lost{border-color:#ef4444}