*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%;background:var(--bg);color:var(--fg);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  -webkit-font-smoothing:antialiased;-webkit-tap-highlight-color:transparent}
button{font:inherit;cursor:pointer;border:0;background:none;color:inherit}
.app{display:flex;height:100vh;height:100dvh;width:100%;overflow:hidden}

/* ---------- Vídeo ---------- */
.stage{position:relative;flex:0 0 50%;background:#000;overflow:hidden;user-select:none;-webkit-user-select:none}
.stage video{position:absolute;inset:0;width:100%;height:100%;object-fit:contain;background:#000}
.stage video::-webkit-media-controls{display:none!important}
.topbar{position:absolute;left:0;right:0;top:0;z-index:3;padding-top:env(safe-area-inset-top);
  background:linear-gradient(rgba(0,0,0,.45),rgba(0,0,0,0));pointer-events:none}
.track{position:relative;height:4px;background:rgba(255,255,255,.25);pointer-events:auto;cursor:pointer}
.track::after{content:"";position:absolute;left:0;right:0;top:-8px;bottom:-8px} /* zona táctil */
.track-fill{position:absolute;left:0;top:0;bottom:0;width:0;background:#fff;transition:width .25s linear}
.track-req{position:absolute;left:0;top:0;bottom:0;width:0;background:rgba(255,255,255,.35)}
.ctrls{display:flex;justify-content:flex-end;align-items:center;gap:8px;padding:12px 14px;pointer-events:auto}
.time{color:#fff;font-size:12px;font-variant-numeric:tabular-nums;margin-right:4px;text-shadow:0 1px 2px rgba(0,0,0,.4)}
.ctrl{width:30px;height:24px;border:1.5px solid rgba(255,255,255,.85);border-radius:6px;color:#fff;
  display:inline-flex;align-items:center;justify-content:center}
.ctrl svg{width:16px;height:16px}
.ctrl-text{width:auto;min-width:34px;padding:0 6px;font-size:11px;font-weight:600}
.ctrl .i-off{display:none}
.muted .ctrl .i-on{display:none}.muted .ctrl .i-off{display:block}
.no-fullscreen #btnFull{display:none}
.bigplay{position:absolute;left:50%;top:50%;width:72px;height:72px;margin:-36px 0 0 -36px;z-index:2;border-radius:50%;
  background:rgba(255,255,255,.88);color:#111;display:flex;align-items:center;justify-content:center;
  box-shadow:0 4px 24px rgba(0,0,0,.25);transition:transform .15s,opacity .2s}
.bigplay svg{width:30px;height:30px;margin-left:4px}
.bigplay:active{transform:scale(.94)}
.playing .bigplay{opacity:0;pointer-events:none}
.loader{position:absolute;left:50%;top:50%;width:36px;height:36px;margin:-18px 0 0 -18px;border-radius:50%;
  border:3px solid rgba(255,255,255,.25);border-top-color:#fff;animation:spin .8s linear infinite;display:none;z-index:2}
.waiting .loader{display:block}
@keyframes spin{to{transform:rotate(360deg)}}

/* ---------- Panel de respuesta ---------- */
.panel{flex:1 1 50%;background:var(--bg);display:flex;overflow-y:auto}
.panel-inner{width:100%;max-width:420px;margin:auto;padding:32px 24px;display:flex;flex-direction:column;align-items:stretch;gap:14px}
.steps{display:flex;gap:4px;margin-bottom:10px}
.steps span{flex:1;height:3px;border-radius:2px;background:rgba(0,0,0,.1)}
.steps span.on{background:var(--primary)}
.title{font-size:22px;line-height:1.25;font-weight:600}
.subtitle{font-size:15px;line-height:1.5;opacity:.75;white-space:pre-line}
.btn{display:block;width:100%;min-height:52px;padding:14px 20px;border-radius:var(--radius);
  background:var(--primary);color:var(--button-text);font-weight:600;font-size:15px;text-align:center;
  transition:opacity .2s,transform .1s;text-decoration:none}
.btn:active{transform:scale(.98)}
.btn[disabled]{background:#e8e8e8;color:#9a9a9a;cursor:not-allowed;transform:none}
.btn-ghost{background:transparent;color:var(--fg);border:1.5px solid rgba(0,0,0,.18)}
.hint{font-size:13px;text-align:center;opacity:.55;font-variant-numeric:tabular-nums;min-height:18px}
.form{display:flex;flex-direction:column;gap:12px}
.form .prompt{font-size:18px;font-weight:600;line-height:1.3;margin-bottom:4px}
.field input{width:100%;height:50px;padding:0 14px;border:1.5px solid rgba(0,0,0,.16);border-radius:12px;
  font-size:16px;color:var(--fg);background:#fff;outline:none;transition:border-color .15s}
.field input:focus{border-color:var(--primary)}
.consent{display:flex;gap:10px;align-items:flex-start;font-size:12px;line-height:1.45;opacity:.85;white-space:pre-line}
.consent input{flex:0 0 auto;width:18px;height:18px;margin-top:1px;accent-color:var(--primary)}
.consent a{color:inherit}
.footnote{font-size:12px;line-height:1.5;opacity:.7;white-space:pre-line;border-top:1px solid rgba(0,0,0,.08);padding-top:12px}
.end{text-align:center;display:flex;flex-direction:column;gap:16px}
.end .title{white-space:pre-line}
.toast{position:fixed;left:50%;bottom:24px;transform:translate(-50%,40px);opacity:0;z-index:20;
  background:#111;color:#fff;padding:12px 18px;border-radius:12px;font-size:14px;max-width:90vw;
  transition:all .25s;pointer-events:none}
.toast.show{opacity:1;transform:translate(-50%,0)}

/* ---------- Móvil: vídeo a pantalla completa y respuesta superpuesta ---------- */
@media (max-width: 820px){
  .stage video{object-fit:cover}
  .app{display:block;position:relative}
  .stage{position:absolute;inset:0}
  .panel{position:absolute;left:0;right:0;bottom:0;z-index:5;background:transparent;display:block;overflow:visible;
    padding-bottom:env(safe-area-inset-bottom)}
  .panel-inner{max-width:none;padding:18px 16px 22px;background:linear-gradient(rgba(0,0,0,0),rgba(0,0,0,.55) 40%)}
  .panel .steps,.panel .title,.panel .subtitle{display:none}
  .panel .hint{color:#fff;opacity:.8}
  .btn[disabled]{background:rgba(255,255,255,.28);color:rgba(255,255,255,.75)}
  /* Formulario y pantalla final: hoja blanca a pantalla completa */
  .sheet .panel{top:0;background:var(--bg);overflow-y:auto}
  .sheet .panel-inner{background:none;min-height:100%;justify-content:center;padding:28px 20px calc(28px + env(safe-area-inset-bottom))}
  .sheet .panel .title,.sheet .panel .subtitle{display:block}
  .sheet .panel .hint{color:inherit}
}