/* mode + difficulty toolbar */
  .tester-toolbar{
    display: flex; align-items: center; justify-content: space-between;
    gap: 14px 24px; flex-wrap: wrap;
    margin-bottom: clamp(16px, 2vw, 22px);
  }
  .tester-modes, .tester-diff{ display: inline-flex; align-items: center; gap: 6px; flex-wrap: wrap; }
  .tester-diff-label{
    font-family: var(--font-mono); font-size: 10px; letter-spacing: .18em;
    text-transform: uppercase; color: var(--ink-faint); margin-right: 4px;
  }
  .tester-mode-btn, .tester-diff-btn{
    font-family: var(--font-mono); font-size: 11px; letter-spacing: .1em;
    text-transform: uppercase; color: var(--ink-soft);
    background: rgba(255,255,255,.03);
    border: 1px solid var(--line); border-radius: 5px;
    padding: 8px 12px; cursor: pointer;
    transition: color var(--dur-base) var(--ease-out-soft),
                border-color var(--dur-base) var(--ease-out-soft),
                background var(--dur-base) var(--ease-out-soft);
  }
  .tester-diff-btn{ padding: 7px 10px; }
  .tester-mode-btn:hover, .tester-diff-btn:hover{ color: var(--ink); border-color: var(--line-strong); }
  .tester-mode-btn.active{ color: var(--pitch); background: var(--ink); border-color: var(--ink); }
  .tester-diff-btn.active{ color: var(--signal); border-color: rgba(255,89,69,.5); background: rgba(255,89,69,.07); }

  /* multiple-choice options */
  .tester-choices{ display: grid; gap: 10px; margin-top: 4px; }
  .tester-choices[hidden]{ display: none; }
  #tester-freetext[hidden]{ display: none; }
  .tester-choice{
    text-align: left; width: 100%;
    font-family: var(--font-sans); font-size: clamp(14px, 1.05vw, 16px); line-height: 1.5;
    color: var(--ink); background: rgba(255,255,255,.03);
    border: 1px solid var(--line); border-radius: 6px;
    padding: 14px 16px 14px 44px; position: relative; cursor: pointer;
    transition: border-color var(--dur-base) var(--ease-out-soft),
                background var(--dur-base) var(--ease-out-soft);
  }
  .tester-choice::before{
    content: attr(data-key);
    position: absolute; left: 16px; top: 14px;
    font-family: var(--font-mono); font-size: 11px; color: var(--ink-faint);
  }
  .tester-choice:hover:not([disabled]){ border-color: var(--line-strong); background: rgba(255,255,255,.05); }
  .tester-choice[disabled]{ cursor: default; }
  .tester-choice.correct{ border-color: var(--cool); background: rgba(90,155,255,.10); }
  .tester-choice.correct::before{ color: var(--cool); }
  .tester-choice.wrong{ border-color: var(--signal); background: rgba(255,89,69,.10); }
  .tester-choice.wrong::before{ color: var(--signal); }

  /* hint ladder */
  .tester-hint-btn{
    background: none; border: 1px solid var(--line); border-radius: 5px;
    color: var(--ink-soft); font-family: var(--font-mono); font-size: 11px;
    letter-spacing: .14em; text-transform: uppercase; cursor: pointer; padding: 11px 14px;
  }
  .tester-hint-btn:hover:not([disabled]){ color: var(--ink); border-color: var(--line-strong); }
  .tester-hint-btn[disabled]{ opacity: .4; cursor: default; }
  .tester-hint{
    margin: 14px 0 0; font-family: var(--font-mono); font-size: 11px;
    letter-spacing: .1em; color: var(--ink-soft); line-height: 1.9;
  }
  .tester-hint[hidden]{ display: none; }
  .tester-hint b{ color: var(--ink); text-transform: none; }

  /* progress save strip */
  .tester-save{
    display: flex; align-items: center; justify-content: space-between; gap: 14px; flex-wrap: wrap;
    margin: 0 0 clamp(14px,1.8vw,20px); padding: 11px 14px;
    border: 1px solid var(--line); border-radius: 6px; background: rgba(255,255,255,.02);
    font-family: var(--font-mono); font-size: 11px; letter-spacing: .04em; color: var(--ink-soft);
  }
  .tester-save[hidden]{ display: none; }
  .tester-save .ts-msg{ display: inline-flex; align-items: center; gap: 8px; }
  .tester-save b{ color: var(--ink); font-weight: 600; }
  .tester-save.ask{ border-color: rgba(255,89,69,.35); background: rgba(255,89,69,.05); }
  .tester-save.blocked{ border-color: rgba(255,176,119,.4); background: rgba(255,176,119,.05); color: var(--ember); }
  .ts-dot{ width: 6px; height: 6px; border-radius: 50%; background: var(--cool); box-shadow: 0 0 8px var(--cool); }
  .ts-actions{ display: inline-flex; align-items: center; gap: 8px; }
  .ts-btn{
    font-family: var(--font-mono); font-size: 11px; letter-spacing: .12em; text-transform: uppercase;
    color: var(--pitch); background: var(--ink); border: 1px solid var(--ink); border-radius: 5px;
    padding: 7px 12px; cursor: pointer;
  }
  .ts-btn:hover{ background: #fff; }
  .ts-no{
    font-family: var(--font-mono); font-size: 10px; letter-spacing: .14em; text-transform: uppercase;
    color: var(--ink-faint); background: none; border: none; cursor: pointer; padding: 6px 8px;
  }
  .ts-no:hover{ color: var(--ink-soft); }