/* learn.css - Brainlag Learn (maths and science). Built on brainlag.css tokens; light and dark follow the OS
   (or the site's theme switch). Mobile first: the player is one question per screen with a sticky bottom bar.
   No gradients, no pills, no cards inside cards: hierarchy comes from type, spacing and rules. */
:root{
  --ln-right:#13804f; --ln-right-bg:#e2f6ec; --ln-wrong:#b8432f; --ln-wrong-bg:#fdeae5; --ln-self:#1f6fb5; --ln-self-bg:#e3f0fc;
  --ln-lip:#08707a; --ln-ease:cubic-bezier(.22,1,.36,1); --ln-spring:cubic-bezier(.34,1.56,.64,1);
}
:root[data-theme="dark"]{
  --ln-right:#3fd59a; --ln-right-bg:#10301f; --ln-wrong:#ff8a80; --ln-wrong-bg:#3a1a19; --ln-self:#7cc0f5; --ln-self-bg:#13304f; --ln-lip:#075a62;
}
body.ln{background:var(--paper)}

/* ---------------------------------------------------------------- hub and unit pages */
main.wrap.ln-main{max-width:var(--wrap);padding-top:28px;padding-bottom:8px}
.ln-main h1{margin:6px 0 10px}
.ln-lead{font-size:18px;color:var(--ink-2);max-width:62ch;line-height:1.55;margin:0 0 20px}
.ln-sub{color:var(--ink-3);margin:-6px 0 12px;font-size:15px}
.ln-crumb{font-size:14.5px;color:var(--ink-3);margin:0}
.ln-crumb a{color:var(--study-ink);font-weight:700}
.ln-subj{margin:34px 0 0}
.ln-units,.ln-qlist{list-style:none;margin:0;padding:0;border-top:2px solid var(--rule)}
.ln-units > li,.ln-qlist > li{border-bottom:2px solid var(--rule)}
.ln-units a,.ln-qlist a{display:grid;gap:3px;padding:16px 4px;color:var(--ink)}
.ln-qlist > li > span{display:block;padding:12px 4px 0}.ln-qlist > li > span.m{padding:2px 4px 12px}
.ln-units a:hover .t,.ln-qlist a:hover .t{color:var(--study-ink)}
.ln-units .t,.ln-qlist .t{font:600 19px/1.25 var(--f-display)}
.ln-units .d{color:var(--ink-2);font-size:16px;max-width:70ch}
.ln-units .m,.ln-qlist .m{color:var(--ink-3);font-size:14.5px}
.ln-more{margin:22px 0 0}.ln-more a{color:var(--study-ink);font-weight:700}
.ln-legal{margin:44px 0 0;color:var(--ink-3);font-size:13.5px;max-width:80ch;line-height:1.5}
.ln-cols{display:grid;grid-template-columns:minmax(0,1fr);gap:8px 56px}
@media (min-width:980px){.ln-cols{grid-template-columns:minmax(0,1fr) 340px}}
.ln-cols h2{font-size:21px;margin:26px 0 10px}
.ln-lessons{list-style:none;margin:0;padding:0}
.ln-lessons li a{display:grid;grid-template-columns:44px minmax(0,1fr) 28px;gap:14px;align-items:start;padding:14px 4px;border-bottom:2px solid var(--rule);color:var(--ink)}
.ln-lessons li:first-child a{border-top:2px solid var(--rule)}
.ln-lessons .n{width:44px;height:44px;border-radius:14px;display:grid;place-items:center;font:700 18px var(--f-display);background:var(--study-tint);color:var(--study-ink);box-shadow:inset 0 -3px 0 rgba(var(--ink-rgb),.12)}
.ln-lessons .body{display:grid;gap:3px}
.ln-lessons .t{font:600 19px/1.25 var(--f-display)}
.ln-lessons .d{color:var(--ink-2);font-size:15.5px}
.ln-lessons .m{color:var(--ink-3);font-size:14px}
.ln-lessons a:hover .t{color:var(--study-ink)}
.ln-lessons li.done .n{background:var(--study);color:#fff}
:root[data-theme="dark"] .ln-lessons li.done .n{color:#04161c}
.ln-lessons li.done .st::after{content:'';display:block;width:12px;height:22px;margin:8px 0 0 8px;border:solid var(--study-ink);border-width:0 4px 4px 0;transform:rotate(45deg)}
.ln-aside{padding-top:2px}
.ln-can{margin:0;padding-left:20px;color:var(--ink-2)}.ln-can li{margin:0 0 6px}
.ln-spec{list-style:none;margin:0;padding:0;color:var(--ink-2);font-size:15px}
.ln-spec li{padding:8px 0;border-bottom:1px solid var(--rule)}.ln-spec span{color:var(--ink-3)}
.ln-due{margin:26px 0 0}.ln-due a{color:var(--study-ink);font-weight:700}

/* ---------------------------------------------------------------- the player */
body.ln-play{min-height:100dvh}
.lp{min-height:100dvh;display:flex;flex-direction:column}
.lp-top{position:sticky;top:0;z-index:20;display:flex;align-items:center;gap:14px;padding:12px max(16px,env(safe-area-inset-left)) 10px;background:var(--paper)}
.lp-x,.lp-snd{flex:none;width:44px;height:44px;display:grid;place-items:center;border-radius:12px;color:var(--ink-3);background:none;border:0;cursor:pointer}
.lp-x:hover,.lp-snd:hover{color:var(--ink);background:var(--sunk)}
.lp-snd .off{display:none}.lp-snd.off .off{display:inline}.lp-snd.off .on{display:none}
.lp-bar{flex:1;height:16px;border-radius:8px;background:var(--sunk);overflow:hidden;position:relative}
.lp-bar > span{position:absolute;inset:0;background:var(--study);transform-origin:left center;transform:scaleX(0);border-radius:8px;
  transition:transform .7s var(--ln-spring);box-shadow:inset 0 4px 0 rgba(255,255,255,.28)}
.lp-bar.sheen::after{content:'';position:absolute;top:0;bottom:0;width:40%;left:-40%;background:rgba(255,255,255,.35);transform:skewX(-20deg);animation:lnSheen .45s .55s ease-out both}
@keyframes lnSheen{to{left:110%}}
.lp-meta{flex:none;display:flex;gap:12px;align-items:center;font-weight:700;color:var(--ink-2);font-size:15px}
.lp-meta:empty{display:none}
.lp-combo{color:var(--gold-ink)}.lp-combo.pop{animation:lnPop .26s var(--ln-spring)}
.lp-clock{font-variant-numeric:tabular-nums}.lp-clock.low{color:var(--ln-wrong)}

.lp-stage{flex:1;width:100%;max-width:900px;margin:0 auto;padding:10px 16px 200px}
.lp-screen > h1,.lq-title{font-size:clamp(23px,4.6vw,30px);margin:10px 0 14px;outline:none}
.lq-title .of{color:var(--ink-3);font-weight:500}
.lp-screen.enter{animation:lnIn .32s var(--ln-ease) both}
@keyframes lnIn{from{opacity:0;transform:translateX(18px)}to{opacity:1;transform:none}}
.lp-prose{font-size:17.5px;line-height:1.65;color:var(--ink)}
.lp-prose p,.lp-prose ul,.lp-prose ol{max-width:66ch}
.lp-prose h3{margin:22px 0 6px}
.lp-prose code{font-family:var(--f-mono);background:var(--sunk);padding:1px 6px;border-radius:6px}
.lp-prose .fml{font:600 21px/1.6 var(--f-display);text-align:center;margin:18px 0;padding:14px 8px;border-top:2px solid var(--rule);border-bottom:2px solid var(--rule);max-width:none}
.lp-prose .ln-note{border-left:4px solid var(--gold);padding:4px 0 4px 14px;color:var(--ink-2)}
.wk{counter-reset:wk;list-style:none;padding:0;margin:14px 0 18px;max-width:62ch}
.wk li{counter-increment:wk;display:grid;grid-template-columns:30px 1fr;gap:10px;padding:7px 0;border-bottom:1px solid var(--rule)}
.wk li::before{content:counter(wk);font-weight:700;color:var(--study-ink)}
figure.lgraph{margin:14px 0 18px;max-width:600px}
.lgr{width:100%;height:auto;display:block;font:500 12.5px var(--f-body);touch-action:manipulation}
.lgr .mn{stroke:rgba(var(--ink-rgb),.08);stroke-width:1}.lgr .mj{stroke:rgba(var(--ink-rgb),.2);stroke-width:1}
.lgr .axes line{stroke:var(--ink);stroke-width:2}
.lgr text{fill:var(--ink-2)}.lgr .lab{fill:var(--ink);font-weight:700;font-size:13.5px}
.lgr .ln{fill:none;stroke:var(--study-ink);stroke-width:3;stroke-linejoin:round;stroke-linecap:round}
.lgr .tan{stroke:var(--pink-ink);stroke-width:2.5;stroke-dasharray:7 5}
.lgr .pt{fill:var(--ink)}.lgr .pl{fill:var(--ink);font-weight:700;font-size:14px}
.lgr .hit{fill:transparent;cursor:crosshair}
.lgr .cross{stroke:var(--blue-ink);stroke-width:2.6;stroke-linecap:round;pointer-events:none}
.lq-stem .qt,.lp-prose table{border-collapse:collapse;margin:10px 0 14px;font-variant-numeric:tabular-nums}
.lq-stem .qt th,.lq-stem .qt td{border:2px solid var(--rule-2);padding:6px 10px;text-align:center}
.lq-stem .qt th{text-align:left;font-weight:600;color:var(--ink-2)}
.lq-stem{font-size:17.5px;line-height:1.6}

/* tools inside a lesson: the real tool page in a frame, its chrome hidden */
.lp-try .lp-tool,.lp-tool{margin:16px -4px 0;position:relative}
.lp-tool iframe{display:block;width:100%;border:0;background:transparent;opacity:0;transition:opacity .25s}
.lp-tool.ready iframe{opacity:1}
.lp-toolnote{font-size:14px;margin:8px 4px 0}.lp-toolnote a{color:var(--study-ink);font-weight:700}
@media (min-width:1000px){.lp-stage:has(.lp-try.is-on){max-width:1100px}}

/* a question */
.lq-part{padding:16px 0 18px;border-top:2px solid var(--rule)}
.lq-part:first-of-type{border-top:0}
.lq-prompt{display:flex;gap:4px 10px;align-items:baseline;font-size:17.5px;line-height:1.55}.lq-prompt .pt{flex:1;min-width:0}
.lq-prompt .pl{font-weight:700;color:var(--ink-2)}
.lq-prompt .pt p{margin:0}
.lq-prompt .lq-mk{color:var(--ink-3);font-size:14px;white-space:nowrap}
.lq-in{margin:12px 0 0}
.lq-in.shake{animation:lnShake .32s ease-out}
@keyframes lnShake{0%,100%{transform:none}20%{transform:translateX(-7px)}40%{transform:translateX(6px)}60%{transform:translateX(-4px)}80%{transform:translateX(2px)}}
.lq-line{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.lq-line .lab{font-weight:700;color:var(--ink-2);min-width:4ch}
.lq-line .u{font-weight:700;color:var(--ink-2);font-size:18px}
.lq-field,.lq-cell,.lq-write{font:500 20px var(--f-body);color:var(--ink);background:var(--surface);border:2px solid var(--rule-2);border-radius:14px;padding:10px 14px;min-height:52px;
  transition:border-color .15s,box-shadow .15s}
.lq-field{width:min(240px,100%)}.lq-field.wide{width:min(440px,100%)}.lq-field.unit{width:120px}
.lq-cell{width:84px;min-height:46px;text-align:center;padding:8px 6px;font-size:18px}
.lq-write{width:100%;font-size:17px;line-height:1.5;min-height:140px;resize:vertical}
.lq-field:focus,.lq-cell:focus,.lq-write:focus{outline:none;border-color:var(--study);box-shadow:0 0 0 4px color-mix(in srgb,var(--study) 22%,transparent)}
.lq-field[readonly],.lq-cell[readonly]{background:var(--sunk)}
.lq-syms{display:flex;flex-wrap:wrap;gap:8px;margin:10px 0 0}
.lq-sym{min-width:48px;height:44px;border-radius:12px;border:2px solid var(--rule-2);background:var(--surface);color:var(--ink);font:600 18px var(--f-body);cursor:pointer;box-shadow:inset 0 -3px 0 rgba(var(--ink-rgb),.1)}
.lq-sym:active{transform:translateY(2px);box-shadow:none}
.lq-read{margin:8px 0 0;font-size:14.5px;color:var(--ink-3);min-height:1.4em}.lq-read.bad{color:var(--ln-wrong)}
.lq-hint{color:var(--ink-3);font-size:14.5px;margin:8px 0}
.lq-hinted{margin:8px 0 0;padding:8px 12px;border-left:4px solid var(--gold);color:var(--ink-2);font-size:15.5px}
.lq-scroll{overflow-x:auto;padding-bottom:4px}
.lq-table{border-collapse:collapse;font-variant-numeric:tabular-nums}
.lq-table th,.lq-table td{border:2px solid var(--rule-2);padding:6px;text-align:center;min-width:64px;font-size:16px}
.lq-table th{font-weight:600;color:var(--ink-2)}
.lq-plotin{display:flex;flex-wrap:wrap;gap:8px 14px}
.lq-plotin .pi{display:flex;align-items:center;gap:6px;font-size:15px;color:var(--ink-2)}
.lq-plotin .lq-cell{width:70px}

/* answer tiles */
.t-mcq{display:grid;gap:12px}
@media (min-width:640px){.t-mcq:has(.mini){grid-template-columns:repeat(2,minmax(0,1fr))}}
.lq-tile{display:flex;align-items:center;gap:14px;width:100%;min-height:60px;padding:12px 16px;text-align:left;font:500 18px/1.35 var(--f-body);color:var(--ink);
  background:var(--surface);border:2px solid var(--rule-2);border-radius:16px;box-shadow:0 4px 0 var(--rule-2);cursor:pointer;
  transition:border-color .12s,background-color .12s,box-shadow .09s,transform .09s var(--ln-spring)}
.lq-tile .k{flex:none;width:30px;height:30px;border-radius:9px;border:2px solid var(--rule-2);display:grid;place-items:center;font-size:14px;font-weight:700;color:var(--ink-3)}
.lq-tile:hover{border-color:color-mix(in srgb,var(--study) 55%,var(--rule-2))}
.lq-tile:active{transform:translateY(4px);box-shadow:0 0 0 var(--rule-2)}
.lq-tile[aria-pressed="true"]{border-color:var(--study);background:var(--study-tint);box-shadow:0 4px 0 var(--study)}
.lq-tile[aria-pressed="true"] .k{border-color:var(--study);color:var(--study-ink)}
.lq-tile.pop{animation:lnTile .22s var(--ln-spring)}
@keyframes lnTile{0%{transform:scale(.96)}40%{transform:scale(1.04)}100%{transform:none}}
.lq-tile.right{border-color:var(--ln-right);background:var(--ln-right-bg);box-shadow:0 4px 0 var(--ln-right)}
.lq-tile.wrong{border-color:var(--ln-wrong);background:var(--ln-wrong-bg);box-shadow:0 4px 0 var(--ln-wrong)}
.lq-tile:disabled{cursor:default}
.lq-tile .mini{display:block;width:132px;height:auto}
.mini .ax{stroke:var(--ink-3);stroke-width:1.5}.mini .cv{fill:none;stroke:var(--study-ink);stroke-width:3}.mini text{font:600 11px var(--f-body);fill:var(--ink-2)}

/* results inside a part */
.lq-res:empty{display:none}
.lq-res{margin:12px 0 0}
.lq-res .sc{margin:0;font-size:15.5px}
.lq-part.is-right .sc b{color:var(--ln-right)}.lq-part.is-wrong .sc b{color:var(--ln-wrong)}.lq-part.is-part .sc b{color:var(--gold-ink)}
.lq-res .say{margin:4px 0 0;color:var(--ink-2)}
.lq-res .ans{margin:8px 0 0;font-weight:700}
.ms{margin:12px 0 0;padding:12px 0 0;border-top:1px dashed var(--rule-2)}
.msh{margin:0 0 6px;font-weight:700;color:var(--ink-2);font-size:15px}
.ms ul{list-style:none;margin:0;padding:0;display:grid;gap:6px}
.ms li{font-size:15.5px;line-height:1.45}
.ms label{display:flex;gap:10px;align-items:flex-start;cursor:pointer}
.ms input{width:22px;height:22px;margin:1px 0 0;accent-color:var(--study);flex:none}
.ms .sch b{display:inline-block;min-width:2.4em;color:var(--study-ink)}
.lv{display:grid;gap:8px}
.lvl{display:flex;gap:10px;align-items:flex-start;padding:10px 12px;border:2px solid var(--rule);border-radius:14px;cursor:pointer}
.lvl:has(input:checked){border-color:var(--study);background:var(--study-tint)}
.lq-ws{margin:22px 0 0;padding:16px 0 0;border-top:2px solid var(--rule)}
.lq-ws h2{font-size:19px;margin:0 0 8px}
.lq-ws ol{margin:0;padding-left:22px;display:grid;gap:6px;font-size:16.5px}
.lq-ws .own{margin:10px 0 0;color:var(--ink-3);font-size:13.5px}
.lp-loading,.lp-err{color:var(--ink-3);padding:30px 0}

/* bottom bar and feedback sheet */
.lp-foot{position:fixed;left:0;right:0;bottom:0;z-index:30;background:var(--paper);border-top:2px solid var(--rule)}
.lp-sheet{max-width:900px;margin:0 auto;padding:0 16px}
.lp-sheet:empty{display:none}
.lp-sheet.is-right,.lp-sheet.is-wrong,.lp-sheet.is-neutral{padding-top:16px}
.lp-foot:has(.lp-sheet.is-right){background:var(--ln-right-bg);border-top-color:transparent}
.lp-foot:has(.lp-sheet.is-wrong){background:var(--ln-wrong-bg);border-top-color:transparent}
.lp-foot:has(.lp-sheet.is-neutral){background:var(--ln-self-bg);border-top-color:transparent}
.lp-sheet.rise{animation:lnRise .3s var(--ln-ease)}
@keyframes lnRise{0%{transform:translateY(100%)}62%{transform:translateY(-6px)}100%{transform:none}}
.lp-sh .t{margin:0;font:700 22px var(--f-display)}
.is-right .lp-sh .t{color:var(--ln-right)}.is-wrong .lp-sh .t{color:var(--ln-wrong)}.is-neutral .lp-sh .t{color:var(--ln-self)}
.lp-sh .l{margin:4px 0 0;color:var(--ink);max-width:62ch}
.lp-link{background:none;border:0;padding:6px 0;margin:4px 0 0;color:var(--study-ink);font:700 15.5px var(--f-body);text-decoration:underline;text-underline-offset:3px;cursor:pointer}
.lp-actions{max-width:900px;margin:0 auto;display:flex;gap:12px;padding:14px 16px calc(14px + env(safe-area-inset-bottom))}
.lp-btn{flex:1;display:inline-flex;align-items:center;justify-content:center;min-height:54px;padding:0 18px;border-radius:16px;border:0;cursor:pointer;
  font:700 17px var(--f-body);letter-spacing:.01em;text-align:center;background:var(--study);color:#fff;box-shadow:0 4px 0 var(--ln-lip);
  transition:transform .09s var(--ln-spring),box-shadow .09s,background-color .15s}
:root[data-theme="dark"] .lp-btn{color:#04161c}
.lp-btn:active{transform:translateY(4px);box-shadow:0 0 0 var(--ln-lip);transition-duration:0s}
.lp-btn:disabled{background:var(--sunk);color:var(--ink-3);box-shadow:0 4px 0 var(--rule-2);cursor:default;transform:none}
.lp-btn.quiet,:root[data-theme="dark"] .lp-btn.quiet{background:var(--surface);color:var(--ink);border:2px solid var(--rule-2);box-shadow:0 4px 0 var(--rule-2)}
.lp-foot:has(.is-right) .lp-btn:not(.quiet){background:var(--ln-right);box-shadow:0 4px 0 color-mix(in srgb,var(--ln-right) 70%,#000)}
.lp-foot:has(.is-wrong) .lp-btn:not(.quiet){background:var(--ln-wrong);box-shadow:0 4px 0 color-mix(in srgb,var(--ln-wrong) 70%,#000)}
:root[data-theme="dark"] .lp-foot:has(.is-wrong) .lp-btn:not(.quiet),:root[data-theme="dark"] .lp-foot:has(.is-right) .lp-btn:not(.quiet){color:#0b1626}
@media (min-width:700px){.lp-actions{justify-content:flex-end}.lp-btn{flex:0 0 auto;min-width:180px}}

/* number keypad (touch screens) */
.lp-pad{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;max-width:520px;margin:0 auto;padding:12px 16px 0}
.lp-key{min-height:50px;border-radius:12px;border:2px solid var(--rule-2);background:var(--surface);color:var(--ink);font:600 21px var(--f-body);box-shadow:0 3px 0 var(--rule-2)}
.lp-key:active{transform:translateY(3px);box-shadow:none}
.lp-key.wide{background:var(--sunk)}
body.pad-on .lp-stage{padding-bottom:440px}

/* the end of a lesson or test */
.lp-done{text-align:center;position:relative;padding-top:10px}
.lp-done > h1{font-size:clamp(28px,6vw,38px);animation:lnRiseT .3s .3s var(--ln-spring) both}
@keyframes lnRiseT{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}
.ln-noodle{display:block;width:88px;height:91px;margin:8px auto 0}
.ln-noodle.hop{animation:lnHop .6s var(--ln-ease)}
@keyframes lnHop{0%{transform:translateY(3px)}20%{transform:translateY(-16px)}50%{transform:translateY(0)}65%{transform:translateY(-4px)}100%{transform:none}}
.lp-sub{color:var(--ink-2);margin:4px auto 0;max-width:56ch}
.lp-stats{display:flex;justify-content:center;flex-wrap:wrap;gap:12px 40px;margin:24px 0 8px}
.lp-stats > div{display:grid;justify-items:center;gap:2px;animation:lnRiseT .3s var(--ln-ease) both}
.lp-stats > div:nth-child(1){animation-delay:.65s}.lp-stats > div:nth-child(2){animation-delay:.8s}.lp-stats > div:nth-child(3){animation-delay:.95s}
.lp-stats dt{color:var(--ink-3);font-size:14px;font-weight:600}
.lp-stats dd{margin:0;font:700 34px var(--f-display);color:var(--study-ink);font-variant-numeric:tabular-nums}
.lp-stats span{color:var(--ink-3);font-size:14px}
.lp-intro .lp-stats{justify-content:flex-start}.lp-intro{text-align:left}
.lp-confetti{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}
.lp-result{text-align:left}.lp-result > h1,.lp-result > .ln-noodle{text-align:center}
.lp-result .lp-stats{justify-content:center}
.lp-result h2{font-size:20px;margin:28px 0 10px}
.lp-bars{list-style:none;margin:0;padding:0;display:grid;gap:10px}
.lp-bars li{display:grid;grid-template-columns:minmax(0,1fr) minmax(80px,1fr) 56px;gap:12px;align-items:center;font-size:15.5px}
.lp-bars .bar{display:block;align-self:center;height:12px;border-radius:6px;background:var(--sunk);overflow:hidden}
.lp-bars .bar i{display:block;width:100%;height:100%;background:var(--study);transform-origin:left}
.lp-bars .v{text-align:right;font-variant-numeric:tabular-nums;color:var(--ink-2)}
.lp-rq{border-top:2px solid var(--rule)}
.lp-rq summary{display:flex;justify-content:space-between;gap:12px;padding:14px 2px;cursor:pointer;font-weight:600}
.lp-rq .lq{padding:0 0 16px}
.lp-jump{padding-left:22px}
.lp-list h2{font-size:20px;margin:26px 0 8px}
.lp-lock{text-align:left}.lp-lock .ln-noodle{margin:6px 0 0}
.lp-facts{color:var(--ink-3)}
.lp-plusline{margin:22px 0 0;font-weight:600}.lp-plusline a{color:var(--study-ink)}
.lp-lock-in{display:flex;gap:16px;align-items:flex-start}.lp-lock-in .ln-noodle{margin:0;flex:none}.lp-lock-in a{color:var(--study-ink);font-weight:700}

@media (prefers-reduced-motion:reduce){
  .lp-screen.enter,.lp-sheet.rise,.lq-tile.pop,.lq-in.shake,.ln-noodle.hop,.lp-done > h1,.lp-stats > div,.lp-combo.pop{animation:none}
  .lp-bar > span{transition:none}.lp-bar.sheen::after{display:none}
}
@keyframes lnPop{0%{transform:scale(1)}40%{transform:scale(1.18)}100%{transform:scale(1)}}
.lq-intro{margin:6px 0 4px;padding:0 0 12px;border-bottom:2px solid var(--rule);color:var(--ink-2);font-size:16.5px}
.lq-intro p{margin:0 0 6px}.lq-introt{font-weight:700;color:var(--study-ink)}
.lp-stats dd span{font:inherit;color:inherit}

/* ================================================================ October 2026: motion and the streak (learn-fx.js)
   Timings and reasons: handoff-2026-10-06/LEARN_MOTION_SPEC.md. Transform and opacity only; Noodle never scales. */
/* a wide table in a lesson scrolls inside itself instead of widening the page on a phone */
.lp-prose table{display:block;max-width:100%;overflow-x:auto}
/* the player never scrolls sideways: a screen slides in from 18 px right, inside the stage */
.lp-stage{overflow-x:clip}

/* the feedback sheet: a mark that pops, the title lands a frame after the bar rises */
.lp-sh{display:grid;grid-template-columns:auto minmax(0,1fr);gap:12px;align-items:start}
.lp-shx{min-width:0}
.lp-mk{width:38px;height:38px;border-radius:50%;display:grid;place-items:center;color:#fff;margin-top:-3px}
.lp-mk svg{width:22px;height:22px}
.is-right .lp-mk{background:var(--ln-right)}.is-wrong .lp-mk{background:var(--ln-wrong)}.is-neutral .lp-mk{background:var(--ln-self)}
:root[data-theme="dark"] .lp-mk{color:#0b1626}
.lp-sheet:not(.again) .lp-mk{animation:lnMark .36s .06s var(--ln-spring) both}
.lp-sheet:not(.again) .lp-sh .t{animation:lnLand .26s .04s var(--ln-ease) both}
@keyframes lnMark{from{transform:scale(.4) rotate(-20deg);opacity:0}to{transform:none;opacity:1}}
@keyframes lnLand{from{transform:translateY(8px);opacity:0}to{transform:none;opacity:1}}

/* buttons: the face drops onto its lip at once, springs back in 90 ms */
.lp-btn:not(:disabled):active{filter:brightness(.96)}

/* Noodle stands on the action bar, right-hand end, feet on its top edge; one fixed box, so he never changes size */
.lp-coach{position:absolute;right:max(10px,calc(50% - 440px));bottom:calc(100% - 5px);width:90px;height:93px;pointer-events:none;z-index:1;transition:opacity .18s,visibility .18s}
.ln-coach{display:block}
.ln-layer{position:absolute;inset:0}
.ln-layer svg{display:block;width:100%;height:100%;overflow:visible}
body.pad-on .lp-coach{opacity:0;visibility:hidden}
body.coach-off .lp-coach{display:none}
@media (max-height:600px){.lp-coach{display:none}}

/* top bar: room for the bar on a phone; the vibration switch (Android only) */
@media (max-width:440px){.lp-top{gap:6px;padding-left:10px;padding-right:10px}.lp-x,.lp-snd{width:40px;height:40px}.lp-combo .w{display:none}}
.lp-combo{display:inline-flex;align-items:center;gap:4px}
.lp-combo svg{flex:none}

/* combo: from three first tries in a row the bar warms to gold, glows, and a light runs along the fill */
.lp-bar{transition:box-shadow .3s ease}
.lp-bar > span{overflow:hidden;transition:transform .7s var(--ln-spring),background-color .3s ease}
.lp-bar.is-combo{box-shadow:0 0 0 3px color-mix(in srgb,var(--gold) 32%,transparent),0 0 16px color-mix(in srgb,var(--gold) 50%,transparent)}
.lp-bar.is-combo > span{background:var(--gold)}
.lp-bar.is-combo > span::after{content:'';position:absolute;top:0;bottom:0;left:0;width:30%;background:rgba(255,255,255,.45);transform:translateX(-120%) skewX(-20deg);animation:lnComboRun 1.6s .2s ease-in-out infinite}
@keyframes lnComboRun{0%{transform:translateX(-120%) skewX(-20deg)}60%,100%{transform:translateX(380%) skewX(-20deg)}}

/* lesson complete: Noodle, then three figures that count up */
.lp-coach-big{position:relative;display:block;width:124px;height:128px;margin:0 auto}
.lp-done-fx > h1{animation:none}
.lp-tiles{display:grid;grid-template-columns:repeat(auto-fit,minmax(0,1fr));gap:10px;max-width:480px;margin:22px auto 10px}
.lp-tiles > div{display:grid;justify-items:center;gap:2px;padding:10px 4px 12px;border:2px solid var(--rule-2);border-radius:16px;box-shadow:0 4px 0 var(--rule-2);background:var(--surface)}
.lp-tiles dt{font-size:13.5px;font-weight:700;color:var(--ink-3)}
.lp-tiles dd{margin:0;font:700 30px/1.15 var(--f-display);font-variant-numeric:tabular-nums}
.lp-tiles .st-xp{border-color:color-mix(in srgb,var(--gold) 70%,var(--rule-2));box-shadow:0 4px 0 color-mix(in srgb,var(--gold) 70%,var(--rule-2))}
.lp-tiles .st-xp dd{color:var(--gold-ink)}
.lp-tiles .st-acc{border-color:color-mix(in srgb,var(--ln-right) 55%,var(--rule-2));box-shadow:0 4px 0 color-mix(in srgb,var(--ln-right) 55%,var(--rule-2))}
.lp-tiles .st-acc dd{color:var(--ln-right)}
.lp-tiles .st-time dd{color:var(--study-ink)}
.lp-facts2{font-size:15px;color:var(--ink-3)}

/* the streak screen */
.lp-streak{text-align:center;padding-top:4px}
.sk-stage{display:flex;justify-content:center;align-items:flex-end;height:178px;margin:6px auto 0}
.sk-coach{position:relative;display:block;width:104px;height:108px;margin:0 -6px 0 0}
.sk-flame{display:block;font-size:128px;line-height:0;margin-bottom:6px}
.sk-flame .blk-flame{vertical-align:bottom}
.sk-num{margin:6px 0 0;font:800 64px/1 var(--f-display);color:#e8641e;font-variant-numeric:tabular-nums}
:root[data-theme="dark"] .sk-num{color:#ff9a5c}
.sk-roll{display:inline-grid;overflow:hidden;padding:0 4px}
.sk-roll > span{grid-area:1/1;display:block}
.lp-streak > h1{font-size:22px;margin:4px 0 16px}
.sk-week{display:flex;justify-content:center;gap:6px;list-style:none;padding:0;margin:0 auto 14px;max-width:340px}
.sk-week li{flex:1;display:grid;justify-items:center;gap:6px;max-width:42px}
.sk-week .wd{font-size:13px;font-weight:700;color:var(--ink-3)}
.sk-week .is-now .wd{color:var(--ink)}
.sk-week .dot{width:34px;height:34px;border-radius:50%;display:grid;place-items:center;border:2px solid var(--rule-2);background:var(--surface);color:#fff}
.sk-week .dot svg{width:18px;height:18px}
.sk-week .is-done .dot{background:#ff7a3d;border-color:#d4581c}
.sk-week .is-rest .dot{background:#cfe8fa;border-color:#7fb4dd;color:#245c87}
.sk-week .is-today .dot{border-style:dashed;border-color:#ff7a3d}
.sk-line{max-width:34ch}

/* the course path: keycap nodes joined by a line; done (gold, a tick), current (teal, a soft ring), open, Plus */
.ln-lessons.is-path li a{grid-template-columns:56px minmax(0,1fr);gap:16px;padding:12px 4px 20px;border:0;position:relative}
.ln-lessons.is-path li:first-child a{border-top:0}
.ln-lessons.is-path .st{display:none}
.ln-lessons.is-path .n{position:relative;z-index:1;width:56px;height:56px;border-radius:50%;font-size:19px;background:var(--sunk);color:var(--ink-3);box-shadow:0 5px 0 var(--rule-2);transition:transform .09s var(--ln-spring),box-shadow .09s var(--ln-spring)}
.ln-lessons.is-path a:active .n{transform:translateY(4px);box-shadow:0 1px 0 var(--rule-2);transition-duration:0s}
.ln-lessons.is-path .n svg{width:26px;height:26px}
.ln-lessons.is-path li.is-done .n{background:var(--gold);color:#3b2a00;box-shadow:0 5px 0 #c98f12}
.ln-lessons.is-path li.is-current .n{background:var(--study);color:#fff;box-shadow:0 5px 0 var(--ln-lip)}
:root[data-theme="dark"] .ln-lessons.is-path li.is-current .n{color:#04161c}
.ln-lessons.is-path li.is-current .n::before{content:'';position:absolute;inset:-9px -11.5px -14px;border-radius:50%;border:3px solid var(--study);opacity:.45;animation:lnRing 2s ease-in-out infinite}
@keyframes lnRing{0%,100%{transform:scale(.94);opacity:.5}50%{transform:scale(1.04);opacity:.18}}
.ln-lessons.is-path li.is-current .t{color:var(--study-ink)}
.ln-lessons.is-path li.is-lock .n{color:var(--ink-3)}
.ln-seg{position:absolute;left:32px;top:76px;bottom:-12px;width:5px;margin-left:-2.5px;border-radius:3px;background:var(--rule-2);overflow:hidden}
.ln-seg i{display:block;height:100%;background:var(--gold);transform-origin:50% 0;transform:scaleY(0)}
.ln-lessons.is-path li.is-done .ln-seg i{transform:none}
.ln-ring{position:absolute;inset:-6px;border-radius:50%;border:4px solid var(--study);pointer-events:none;opacity:0}

/* the streak on the hub and unit pages */
.ln-streak{float:right;display:inline-flex;align-items:center;gap:6px;margin:2px 0 0 12px;font:800 20px/1 var(--f-display);color:#e8641e;font-variant-numeric:tabular-nums}
:root[data-theme="dark"] .ln-streak{color:#ff9a5c}
.ln-streak .blk-flame{width:22px;vertical-align:middle}
.ln-streak.is-out,.ln-streak.is-frozen{color:var(--ink-3)}

@media (prefers-reduced-motion:reduce){
  .lp-sheet .lp-mk,.lp-sh .t,.lp-bar.is-combo > span::after,.ln-lessons.is-path li.is-current .n::before{animation:none!important}
  .lp-bar,.lp-bar > span,.lp-coach,.ln-lessons.is-path .n{transition:none}
}