/* Discover mode reuses LeerLab's paper, ink, colour and hard-shadow tokens. */
.discover-page { max-width: 920px; margin: 0 auto; }
.discover-page > h1 { margin: 10px 0 8px; font-size: clamp(26px, 5vw, 38px); line-height: 1.15; }
.discover-page > .lede { margin-bottom: 22px; }
.discover-status { padding: 24px; }
.discover-status h2 { font-size: 22px; }
.discover-status p { max-width: 52ch; }
.discover-progress { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; align-items: center; margin: 0 0 18px; }
.discover-progress p { margin: 0; font-size: 14px; font-weight: 600; }
.discover-progress > div { display: flex; gap: 10px; }
.discover-progress button { min-width: 44px; min-height: 44px; border: var(--line) solid var(--ink); border-radius: 10px; background: var(--card); font-weight: 700; }
.discover-progress button[aria-current="step"] { background: var(--yellow); box-shadow: var(--sh-sm); }
.discover-work { padding: clamp(16px, 4vw, 30px); }
.discover-work h2 { margin: 0 0 12px; font-size: clamp(23px, 4vw, 30px); line-height: 1.2; scroll-margin-top: 20px; }
.discover-intro { max-width: 58ch; margin: 0 0 20px; }
.discover-task { padding: 14px 16px; background: var(--sand); border: var(--line) solid var(--ink); border-radius: 10px; margin: 0; }
.discover-visual { margin: 18px 0; }
.discover-visual svg { width: 100%; max-height: 300px; display: block; overflow: visible; }
.discover-visual svg text { font: 600 22px var(--font); fill: var(--ink); stroke: none; }
.discover-visual svg .discover-svg-result { font-size: 34px; font-weight: 800; }
.discover-words { display: flex; flex-wrap: wrap; gap: 12px; padding: 22px 0; }
.discover-words button { min-height: 54px; padding: 10px 15px; font-size: clamp(18px, 3vw, 24px); font-weight: 700; background: var(--card); border: var(--line) solid var(--ink); border-radius: 10px; box-shadow: var(--sh-sm); }
.discover-words button[aria-pressed="true"], .discover-check button[aria-pressed="true"] { background: var(--yellow); outline: 2px solid var(--ink); outline-offset: 2px; }
.discover-slider { display: block; font-weight: 600; margin: 0 0 20px; }
.discover-slider > span { display: flex; align-items: center; gap: 16px; }
.discover-slider input { flex: 1; min-width: 0; min-height: 48px; accent-color: var(--purple); cursor: pointer; }
.discover-slider output { min-width: 56px; text-align: center; padding: 8px; border: var(--line) solid var(--ink); border-radius: 8px; background: var(--yellow); font-variant-numeric: tabular-nums; }
.discover-hint { font-size: 14px; color: var(--ink-2); margin: 8px 0 16px; }
.discover-items { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.discover-items button { display: flex; align-items: center; gap: 10px; min-height: 52px; padding: 10px; border: var(--line) solid var(--ink); border-radius: 10px; background: var(--card); text-align: left; overflow-wrap: anywhere; }
.discover-items button span { flex: none; font-weight: 800; }
.discover-items button small { margin-left: auto; }
.discover-items button[aria-pressed="true"] { background: var(--yellow); }
.discover-detail { min-height: 64px; margin: 16px 0 24px; font-weight: 600; }
.discover-check { border: 0; padding: 0; margin: 20px 0 12px; display: grid; gap: 10px; }
.discover-check legend { float: left; width: 100%; margin-bottom: 12px; font-weight: 700; }
.discover-check button { min-height: 48px; text-align: left; padding: 12px 16px; border: var(--line) solid var(--ink); border-radius: 10px; background: var(--card); }
.discover-feedback { min-height: 32px; margin: 12px 0; font-weight: 600; }
.discover-feedback.is-correct { padding: 12px 16px; border: var(--line) solid var(--ink); background: var(--lime); border-radius: 10px; }
.discover-actions, .discover-bottom { display: flex; flex-wrap: wrap; gap: 14px; align-items: center; }
.discover-actions .btn { font-size: 15px; padding: 10px 16px; }
.discover-bottom { justify-content: space-between; margin-top: 24px; padding-top: 20px; border-top: 2px solid var(--ink); }
.discover-reset { border: 0; background: transparent; text-decoration: underline; text-underline-offset: 4px; min-height: 44px; text-align: left; padding: 0; }
.discover-more { margin-top: 24px; }
.discover-more a { font-weight: 700; text-underline-offset: 4px; }
.discover-work .btn:disabled { opacity: .5; cursor: default; box-shadow: none; }
.lesson-modes { display: grid; gap: 12px; margin-bottom: 18px; }
.lesson-modes .discover-launch { background: var(--lime); }
@media (min-width: 640px) { .lesson-modes { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 480px) {
  .discover-items { grid-template-columns: 1fr; }
  .discover-actions, .discover-bottom { align-items: stretch; flex-direction: column; }
  .discover-actions .btn, .discover-bottom .btn { width: 100%; }
}

/* §2.3: the same LeerLab paper and ink, with movement doing the teaching. */
.negative-page { max-width: 900px; }
.negative-page > .lede { max-width: 52ch; }
.negative-progress { display: flex; flex-wrap: wrap; gap: 10px; justify-content: space-between; font-size: 14px; font-weight: 600; margin-bottom: 18px; }
.negative-track { flex-basis: 100%; height: 12px; overflow: hidden; border-radius: 4px; background: var(--sand); }
.negative-track i { display: block; height: 100%; background: var(--ink); transform-origin: left; transition: transform .25s ease-out; }
.negative-topics { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 20px; }
.negative-topics button { display: flex; align-items: center; gap: 8px; min-height: 46px; padding: 8px 12px; border: var(--line) solid var(--ink); border-radius: 10px; background: var(--paper); font-size: 14px; text-align: left; }
.negative-topics button[aria-current="step"] { background: var(--lime); box-shadow: var(--sh-sm); font-weight: 700; }
.negative-topics button span { font-weight: 700; }
.negative-work { padding: clamp(16px, 3.5vw, 30px); }
.negative-heading { display: flex; gap: 16px; align-items: center; justify-content: space-between; }
.negative-heading h2 { margin: 0; font-size: clamp(23px, 4vw, 32px); line-height: 1.2; scroll-margin-top: 24px; }
.negative-pencil { display: grid; flex: none; place-items: center; width: 46px; height: 46px; border: var(--line) solid var(--ink); border-radius: 10px; background: var(--lime); transform: rotate(5deg); }
.negative-pencil svg { width: 28px; height: 28px; }
.negative-prompt { margin: 14px 0 0; max-width: 52ch; }
.negative-expression { font-size: clamp(27px, 5vw, 44px); font-weight: 700; letter-spacing: -.025em; margin: 20px 0 0; font-variant-numeric: tabular-nums; }
.negative-expression span { color: var(--ink-2); font-weight: 400; }
.negative-line { width: 100%; margin: 6px 0 0; touch-action: pan-y; }
.negative-line svg { width: 100%; height: 228px; display: block; overflow: visible; }
.negative-line svg text { font: 500 14px var(--font); fill: var(--ink); }
.negative-line .negative-zone { fill: var(--blue); opacity: .16; }
.negative-line .negative-axis, .negative-line .negative-tick { fill: none; stroke: var(--ink); stroke-width: 2; }
.negative-line .negative-zero { font-weight: 800; }
.negative-line .negative-start-dot { fill: var(--ink); }
.negative-line .negative-start-text { font-size: 13px; }
.negative-line .negative-answer path { fill: var(--yellow); stroke: var(--ink); stroke-width: 2.5; }
.negative-line .negative-answer text { font-size: 18px; font-weight: 700; font-variant-numeric: tabular-nums; }
.negative-line .negative-jump { fill: none; stroke: var(--purple); stroke-width: 3; stroke-linejoin: round; }
.negative-line .negative-walker { fill: var(--purple); stroke: var(--ink); stroke-width: 2; }
.negative-line .negative-direction { font-size: 14px; font-weight: 600; }
.negative-range-label { display: flex; gap: 16px; align-items: center; justify-content: space-between; font-weight: 600; }
.negative-range-label output { min-width: 56px; text-align: center; padding: 6px 12px; background: var(--yellow); border: var(--line) solid var(--ink); border-radius: 8px; font-size: 20px; font-weight: 700; font-variant-numeric: tabular-nums; }
.negative-input { display: flex; align-items: center; gap: 14px; margin-top: 8px; }
.negative-input input { flex: 1; min-width: 0; min-height: 48px; accent-color: var(--purple); }
.negative-input .btn { padding: 10px; min-width: 48px; min-height: 48px; }
.negative-input svg { width: 22px; height: 22px; }
.negative-choices { display: flex; justify-content: center; gap: 16px; }
.negative-choices .btn { min-width: 88px; font-size: 24px; }
.negative-choices [aria-pressed="true"] { background: var(--yellow); }
.negative-response { display: flex; align-items: flex-start; gap: 10px; min-height: 72px; padding: 16px 0; font-size: 15px; }
.negative-response.is-correct { font-weight: 600; }
.negative-response svg { width: 24px; height: 24px; flex: none; padding: 3px; border-radius: 50%; background: var(--lime); }
.negative-actions { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.negative-actions .btn { font-size: 15px; }
.negative-show, .negative-prev { display: flex; align-items: center; gap: 6px; background: none; border: 0; padding: 8px 0; min-height: 44px; font-size: 14px; text-decoration: underline; text-underline-offset: 4px; }
.negative-show svg, .negative-prev svg, .negative-save svg { width: 18px; height: 18px; flex: none; }
.negative-footer { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px; margin-top: 24px; padding-top: 18px; border-top: 2px solid var(--ink); }
.negative-footer .btn { background: var(--lime); }
.negative-work button:disabled { opacity: .45; cursor: default; box-shadow: none; }
.negative-save { display: flex; align-items: center; gap: 8px; font-size: 13px; color: var(--ink-2); margin: 20px 0 0; }
.negative-finish { padding: clamp(20px, 4vw, 36px); }
.negative-finish-mark { display: grid; place-items: center; width: 64px; height: 64px; background: var(--lime); border: var(--line) solid var(--ink); border-radius: var(--r); box-shadow: var(--sh-sm); }
.negative-finish-mark svg { width: 36px; height: 36px; }
.negative-finish h2 { font-size: clamp(26px, 4vw, 36px); margin: 24px 0 12px; }
.negative-finish ul { padding-left: 24px; margin: 24px 0; }
.negative-finish li { margin-bottom: 10px; }
.negative-finish .btn { margin: 0 12px 12px 0; }
@media (max-width: 480px) {
  .negative-topics { gap: 8px; }
  .negative-topics button { font-size: 14px; padding: 8px; }
  .negative-topics button:last-child { flex-basis: 100%; }
  .negative-pencil { display: none; }
  .negative-actions { gap: 10px; }
  .negative-actions .btn { font-size: 14px; padding: 10px 12px; }
  .negative-show { flex-basis: 100%; }
  .negative-footer .btn { font-size: 14px; padding: 10px 12px; }
}
@media (prefers-reduced-motion: reduce) {
  .negative-track i { transition: none; }
}