/* Regs Atlas v3: playful, clean, minimal. Pastel hues h0-h5 per branch, ink lines, one dark ink. */
:root{
  --paper:#FBFAF7;--panel:#FFFFFF;--ink:#16181D;--muted:#5F6470;--faint:#666B76;--line:#E7E4DD;--wash:#F3F1EC;--dot:#E4E1D9;--wire:#C9C4B8;
  --h0:#DCE6FF;--h0i:#2541A3;--h1:#D3F1E3;--h1i:#126B4D;--h2:#FFE1D1;--h2i:#AB4A17;
  --h3:#E8E0FF;--h3i:#5636B0;--h4:#FFF0C2;--h4i:#7D5A00;--h5:#FFDCE3;--h5i:#A8243F;
  --accent:#3D5BD9;--warn:#B8341D;--warn-bg:#FFE0D9;--num:#975700;
  --tip-bg:#16181D;--tip-fg:#F7F6F2;
  --head:'Bricolage Grotesque','DM Sans',system-ui,sans-serif;
  --font:'DM Sans',system-ui,-apple-system,'Segoe UI',Roboto,Arial,sans-serif;
  --mono:'IBM Plex Mono',ui-monospace,Consolas,monospace;
  --shadow:0 1px 2px rgba(22,24,29,.06),0 6px 18px rgba(22,24,29,.06);
  --pop:3px 3px 0 var(--ink);
  --exam-tint:#FFF6E5;--exam-ink:#523B06;--exam-bg:#FFF6E5;--exam-panel:#FFFDF9;--exam-fg:#523B06;--exam-dim:#8A6D24;--exam-gold:#C4890A;--exam-line:#F0DCB0;
  /* Real-world materials in lesson pictures: the same in both themes on purpose (paint, signs, lights at night) */
  --m-asphalt:#5D626C;--m-apron:#80858F;--m-grass:#6E8F5E;--m-paint:#F7F6F0;--m-yellow:#F2C230;--m-red:#D9362B;--m-black:#17181C;--m-white:#FFFFFF;
  --m-night:#0D1017;--m-nrwy:#252A35;--m-ntext:#AEB5C2;--m-light:#FFF4D6;--m-green:#2FD27C;--m-blue:#4A86FF;--m-lred:#FF4B3E;--m-lyellow:#FFC83A;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --paper:#111318;--panel:#1A1D24;--ink:#ECEDF0;--muted:#A4A9B4;--faint:#8E94A0;--line:#2B2F38;--wash:#20242C;--dot:#252932;--wire:#454B57;
  --h0:#243258;--h0i:#B8C9FF;--h1:#173D31;--h1i:#9BE3C3;--h2:#4A2A1B;--h2i:#FFC3A2;
  --h3:#33285A;--h3i:#D2C4FF;--h4:#40361A;--h4i:#FFE08A;--h5:#4A2029;--h5i:#FFB3C2;
  --accent:#8EA6FF;--warn:#FF8A73;--warn-bg:#4A221B;--num:#FFC266;--tip-bg:#ECEDF0;--tip-fg:#16181D;
  --shadow:0 1px 2px rgba(0,0,0,.3),0 8px 22px rgba(0,0,0,.25);color-scheme:dark;
  --exam-tint:#382F18;--exam-ink:#FFD166;--exam-bg:#2A2312;--exam-panel:#382F18;--exam-fg:#FFF3D6;--exam-dim:#DEC892;--exam-gold:#FFD166;--exam-line:#544622}}
:root[data-theme="dark"]{
  --paper:#111318;--panel:#1A1D24;--ink:#ECEDF0;--muted:#A4A9B4;--faint:#8E94A0;--line:#2B2F38;--wash:#20242C;--dot:#252932;--wire:#454B57;
  --h0:#243258;--h0i:#B8C9FF;--h1:#173D31;--h1i:#9BE3C3;--h2:#4A2A1B;--h2i:#FFC3A2;
  --h3:#33285A;--h3i:#D2C4FF;--h4:#40361A;--h4i:#FFE08A;--h5:#4A2029;--h5i:#FFB3C2;
  --accent:#8EA6FF;--warn:#FF8A73;--warn-bg:#4A221B;--num:#FFC266;--tip-bg:#ECEDF0;--tip-fg:#16181D;
  --shadow:0 1px 2px rgba(0,0,0,.3),0 8px 22px rgba(0,0,0,.25);color-scheme:dark;
  --exam-tint:#382F18;--exam-ink:#FFD166;--exam-bg:#2A2312;--exam-panel:#382F18;--exam-fg:#FFF3D6;--exam-dim:#DEC892;--exam-gold:#FFD166;--exam-line:#544622}
.h0{--hb:var(--h0);--hi:var(--h0i)}.h1{--hb:var(--h1);--hi:var(--h1i)}.h2{--hb:var(--h2);--hi:var(--h2i)}
.h3{--hb:var(--h3);--hi:var(--h3i)}.h4{--hb:var(--h4);--hi:var(--h4i)}.h5{--hb:var(--h5);--hi:var(--h5i)}
.hw{--hb:var(--warn-bg);--hi:var(--warn)}

*{box-sizing:border-box}
html{scroll-behavior:smooth;overflow-x:clip}
body{
  margin:0;
  background:var(--paper);
  background-image:radial-gradient(var(--dot) 1px,transparent 1.2px);
  background-size:22px 22px;
  color:var(--ink);
  font-family:var(--font);
  font-size:16px;
  line-height:1.55;
  padding-top:max(0px, env(safe-area-inset-top));
  padding-bottom:max(24px, env(safe-area-inset-bottom));
  padding-left:max(16px, env(safe-area-inset-left));
  padding-right:max(16px, env(safe-area-inset-right));
  -webkit-font-smoothing:antialiased;
  -webkit-tap-highlight-color:transparent;
  overflow-x:clip;
  width:100%;
}
a{color:inherit}button{font:inherit;color:inherit}p{margin:0}
:focus-visible{outline:2.5px solid var(--accent);outline-offset:3px;border-radius:8px}
.ico{width:1.15em;height:1.15em;flex:none;display:inline-block;vertical-align:-.2em}

/* ---------- shell ---------- */
.site{
  max-width:1200px;
  margin-inline:auto;
  padding-block:18px 90px;
  width:100%;
  min-width:0;
  box-sizing:border-box;
}
@media (max-width:640px){.site{padding-block:12px 60px}}
.bar{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:10px;
  margin-bottom:clamp(20px, 3.5vw, 34px);
  flex-wrap:wrap;
  width:100%;
}
.bar a{text-decoration:none;font-weight:600;font-size:14px;display:inline-flex;gap:6px;align-items:center;white-space:nowrap}
.pill{
  border:1.5px solid var(--ink);
  background:var(--panel);
  border-radius:999px;
  padding:7px 15px;
  font-size:13px;
  font-weight:600;
  cursor:pointer;
  box-shadow:2px 2px 0 var(--ink);
  transition:transform .12s,box-shadow .12s;
  display:inline-flex;
  gap:6px;
  align-items:center;
  text-decoration:none;
  touch-action:manipulation;
  white-space:nowrap;
  min-height:38px;
}
.pill:hover{transform:translate(-1px,-1px);box-shadow:3px 3px 0 var(--ink)}
.pill:active{transform:translate(1px,1px);box-shadow:1px 1px 0 var(--ink)}

.pill.pill-upgrade{
  background: var(--h1);
  color: var(--h1i);
  border-color: var(--h1i);
  font-weight: 700;
  box-shadow: 2px 2px 0 var(--ink);
}
.pill.pill-upgrade:hover{
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
  transform: translate(-1px, -1px);
  box-shadow: 3px 3px 0 var(--ink);
}
.pill.pill-upgrade.pending{
  background: var(--wash);
  color: var(--muted);
  border-color: var(--line);
  box-shadow: none;
}
.pill.on{background:var(--ink);color:var(--paper)}
.pill.soft{border-color:var(--line);box-shadow:none;background:var(--panel)}
@media (max-width:440px){
  .pill{padding:6px 12px;font-size:12.5px;min-height:36px}
  .bar a{font-size:13px}
}

.layout{
  display:grid;
  grid-template-columns:clamp(170px, 18vw, 210px) minmax(0,1fr);
  gap:clamp(24px, 3.5vw, 48px);
  align-items:start;
  width:100%;
}
.toc{
  position:sticky;
  top:20px;
  display:flex;
  flex-direction:column;
  gap:4px;
  font-size:14px;
  max-height:calc(100vh - 40px);
  overflow-y:auto;
}
.toc a{
  text-decoration:none;
  color:var(--muted);
  padding:8px 12px;
  border-radius:999px;
  display:flex;
  gap:9px;
  align-items:center;
  line-height:1.25;
  transition:background .2s,color .2s;
  min-height:36px;
  touch-action:manipulation;
}
.toc a i{font-style:normal;font-family:var(--mono);font-size:11px;color:var(--faint)}
.toc a:hover{background:var(--wash);color:var(--ink)}
.toc a.on{background:var(--ink);color:var(--paper)}.toc a.on i{color:var(--paper)}

/* Tablet Portrait & Mobile Section Scroller */
@media (max-width:920px){
  .layout{grid-template-columns:1fr;gap:0}
  .toc{
    display:flex;
    flex-direction:row;
    overflow-x:auto;
    overflow-y:hidden;
    -webkit-overflow-scrolling:touch;
    gap:8px;
    position:sticky;
    top:max(8px, env(safe-area-inset-top));
    z-index:100;
    background:rgba(251,250,247,.94);
    backdrop-filter:blur(12px);
    -webkit-backdrop-filter:blur(12px);
    padding:8px 6px;
    margin-bottom:24px;
    border-radius:999px;
    border:1.5px solid var(--line);
    box-shadow:0 4px 16px rgba(22,24,29,.06);
    scrollbar-width:none;
    max-width:100%;
  }
  :root[data-theme="dark"] .toc,
  @media (prefers-color-scheme:dark){:root:not([data-theme="light"]) .toc{
    background:rgba(26,29,36,.94);
  }}
  .toc::-webkit-scrollbar{display:none}
  .toc a{
    flex-shrink:0;
    white-space:nowrap;
    font-size:13px;
    padding:6px 14px;
    border:1px solid var(--line);
    background:var(--panel);
  }
  .toc a.on{
    border-color:var(--ink);
    background:var(--ink);
    color:var(--paper);
  }
}

main.col{display:flex;flex-direction:column;gap:clamp(48px, 6vw, 84px);min-width:0;width:100%}

/* ---------- hero ---------- */
.hero{
  display:grid;
  grid-template-columns:minmax(0,1fr) minmax(180px, 260px);
  gap:clamp(16px, 3vw, 28px);
  align-items:center;
  width:100%;
}
@media (max-width:760px){.hero{grid-template-columns:1fr}.hero-art{display:none}}
.hero-txt{display:flex;flex-direction:column;gap:12px;min-width:0}
.chip{display:inline-flex;align-items:center;gap:6px;align-self:flex-start;font-size:12.5px;font-weight:700;padding:5px 12px;border-radius:999px;background:var(--hb,var(--h0));color:var(--hi,var(--h0i));white-space:nowrap}
h1{
  font-family:var(--head);
  font-size:clamp(28px,5vw,56px);
  line-height:1.05;
  letter-spacing:-.02em;
  margin:0;
  font-weight:700;
  text-wrap:balance;
  overflow-wrap:break-word;
}
.big{font-size:clamp(15px,1.9vw,20px);color:var(--muted);line-height:1.45;max-width:640px;text-wrap:pretty}
.hero-art svg{width:100%;height:auto;max-width:260px;display:block}
.minute{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%, 200px),1fr));gap:12px}
.note{
  background:var(--hb);
  color:var(--ink);
  border-radius:18px;
  padding:14px 16px 16px;
  display:flex;
  flex-direction:column;
  gap:8px;
  font-size:14.5px;
  line-height:1.45;
  transform:rotate(var(--rot,0deg));
  transition:transform .2s;
  min-width:0;
}
.note:hover{transform:rotate(0) translateY(-3px)}
@media (max-width:540px){.note{transform:none}}
.note b{font-family:var(--head);font-size:24px;line-height:1;color:var(--hi)}
.sect-label{font-size:11.5px;letter-spacing:.14em;text-transform:uppercase;color:var(--faint);font-weight:700;margin-bottom:12px}

/* ---------- lesson ---------- */
.lesson{display:flex;flex-direction:column;gap:18px;scroll-margin-top:clamp(16px, 4vw, 28px);width:100%;min-width:0}
.lh{display:grid;grid-template-columns:auto 1fr;gap:14px;align-items:start;max-width:820px;min-width:0}
.badge{width:46px;height:46px;border-radius:15px;display:grid;place-items:center;background:var(--hb);color:var(--hi);font-family:var(--head);font-weight:700;font-size:19px;flex:none}
.badge .ico{width:22px;height:22px}
.lh h2{
  font-family:var(--head);
  font-size:clamp(20px,2.8vw,30px);
  line-height:1.15;
  margin:4px 0 0;
  letter-spacing:-.01em;
  font-weight:700;
  text-wrap:balance;
  overflow-wrap:break-word;
}
.lh p{color:var(--muted);margin-top:6px;font-size:15px;line-height:1.45}
.stage{
  background:var(--panel);
  border-radius:24px;
  padding:clamp(16px, 3vw, 26px);
  box-shadow:var(--shadow);
  min-width:0;
  width:100%;
  position:relative;
  overflow:hidden;
  box-sizing:border-box;
}
@media (max-width:480px){
  .lh{gap:10px}
  .badge{width:38px;height:38px;border-radius:12px;font-size:16px}
  .stage{padding:14px 12px;border-radius:18px}
}
.under{display:flex;flex-wrap:wrap;gap:12px;align-items:flex-start;width:100%}
.takeaway{
  flex:1 1 340px;
  display:flex;
  gap:12px;
  align-items:flex-start;
  background:var(--ink);
  color:var(--paper);
  border-radius:18px;
  padding:14px 18px;
  font-size:15px;
  line-height:1.45;
  min-width:0;
}
.takeaway .ico{width:20px;height:20px;margin-top:2px;color:var(--h4);flex:none}
.hook{
  flex:0 1 300px;
  background:var(--h4);
  color:var(--ink);
  border-radius:18px;
  padding:12px 16px;
  font-size:14px;
  transform:rotate(-1deg);
  display:flex;
  flex-direction:column;
  gap:2px;
  min-width:0;
}
.hook b{font-size:11px;letter-spacing:.12em;text-transform:uppercase;color:var(--h4i)}
@media (max-width:600px){
  .takeaway,.hook{flex:1 1 100%;transform:none}
}
.scroll{
  overflow-x:auto;
  overflow-y:hidden;
  -webkit-overflow-scrolling:touch;
  overscroll-behavior-x:contain;
  scrollbar-width:thin;
  scrollbar-color:var(--line) transparent;
  max-width:100%;
}
.scroll::-webkit-scrollbar{height:6px}
.scroll::-webkit-scrollbar-track{background:transparent}
.scroll::-webkit-scrollbar-thumb{background:var(--line);border-radius:999px}
.hint{font-size:13px;color:var(--faint)}
.tools{display:flex;gap:8px;flex-wrap:wrap;align-items:center;margin-bottom:16px}

/* ---------- detail card (shared) ---------- */
.detail{
  margin-top:18px;
  border-radius:16px;
  background:var(--wash);
  padding:12px 16px;
  display:flex;
  gap:12px;
  align-items:flex-start;
  min-height:58px;
  transition:background .25s;
  min-width:0;
  box-sizing:border-box;
}
.detail .dot{width:34px;height:34px;border-radius:11px;display:grid;place-items:center;background:var(--hb,var(--panel));color:var(--hi,var(--ink));flex:none}
.detail b{display:block;font-size:15.5px;overflow-wrap:break-word}
.detail p{color:var(--muted);font-size:14.5px;overflow-wrap:break-word}
.detail.fresh{animation:pop .35s both}
@keyframes pop{from{transform:scale(.98);opacity:.4}to{transform:none;opacity:1}}

/* ---------- flowchart (tree) ---------- */
.fc{position:relative;min-width:max-content;padding:4px 4px 8px;max-width:100%}
.fc svg.wires{position:absolute;inset:0;width:100%;height:100%;pointer-events:none;overflow:visible}
.wires path{fill:none;stroke:var(--wire);stroke-width:2;transition:stroke .25s,stroke-width .25s}
.wires path.lit{stroke:var(--ink);stroke-width:2.5}
.wires path.draw{stroke-dasharray:var(--len);stroke-dashoffset:var(--len);animation:draw .8s ease forwards}
@keyframes draw{to{stroke-dashoffset:0}}
.fc-top{display:flex;justify-content:center;margin-bottom:44px}
.fc-cols{display:flex;gap:20px;align-items:flex-start;justify-content:center}
.fc-col{display:flex;flex-direction:column;align-items:flex-start;width:200px}
.fc-leaves{display:flex;flex-direction:column;gap:8px;margin:14px 0 0 24px;width:calc(100% - 24px)}
.fc-leaves .fc-leaves{margin-top:8px;margin-left:18px;width:calc(100% - 18px)}
.fc-leaves[hidden]{display:none}
.nd{
  position:relative;
  border:1.5px solid var(--ink);
  border-radius:14px;
  background:var(--panel);
  padding:9px 12px;
  font-size:13.5px;
  font-weight:600;
  line-height:1.3;
  text-align:left;
  cursor:pointer;
  width:100%;
  display:flex;
  gap:9px;
  align-items:flex-start;
  transition:transform .15s,box-shadow .15s,opacity .25s,background .2s;
  touch-action:manipulation;
  overflow-wrap:break-word;
  word-break:break-word;
}
.nd small{display:block;font-weight:500;font-size:12px;color:var(--muted);margin-top:2px}
.nd .ico{margin-top:1px;color:var(--hi);flex:none}
.nd:hover{transform:translate(-1px,-1px);box-shadow:var(--pop)}
.nd.root{background:var(--ink);color:var(--paper);font-family:var(--head);font-size:18px;padding:11px 20px;border-radius:999px;width:auto;align-items:center}
.nd.root small{color:var(--paper);opacity:.8;font-family:var(--font)}
.nd.br{background:var(--hb);border-color:transparent;font-size:14.5px;padding:11px 13px}
.nd.br small{color:var(--hi)}
.nd.lf{border-color:var(--line);font-weight:500}
.nd.lf.has::after{content:'+';position:absolute;right:8px;top:6px;font-weight:700;color:var(--faint)}
.nd.lf.has.open::after{content:'\2212'}
.nd.lf.has{padding-right:24px}
.nd.on{box-shadow:var(--pop);transform:translate(-1px,-1px);border-color:var(--ink)}
.nd.lf.on{background:var(--hb)}
.fc.focus .nd:not(.on):not(.root){opacity:.45}
.fc.stacked .fc-cols{flex-direction:column;align-items:stretch;gap:14px;padding-left:24px}
.fc.stacked .fc-top{justify-content:flex-start;margin-bottom:18px}
.fc.stacked .fc-col{width:auto}
.fc.stacked{min-width:0}
@media (max-width:480px){
  .fc.stacked .fc-cols{padding-left:16px;gap:12px}
  .fc-leaves{margin:10px 0 0 16px;width:calc(100% - 16px)}
  .fc-leaves .fc-leaves{margin-left:12px;width:calc(100% - 12px)}
  .nd{padding:8px 10px;font-size:13px}
  .nd.root{font-size:16px;padding:10px 16px}
}

/* ---------- decision flowchart ---------- */
.df{position:relative}
.df svg.wires{position:absolute;inset:0;pointer-events:none;overflow:visible}
.df .wires text{font-size:12px;font-weight:700;fill:var(--muted);font-family:var(--font)}
.df .wires text.lit{fill:var(--ink)}
.dn{
  position:absolute;
  border-radius:16px;
  padding:11px 13px;
  font-size:14px;
  line-height:1.3;
  font-weight:600;
  background:var(--panel);
  border:1.5px solid var(--ink);
  transition:opacity .3s,box-shadow .2s,transform .2s;
  cursor:pointer;
  display:flex;
  flex-direction:column;
  gap:8px;
  text-align:left;
  touch-action:manipulation;
}
.dn.q::before{content:'?';position:absolute;top:-11px;left:-11px;width:24px;height:24px;border-radius:50%;background:var(--h4);color:var(--h4i);border:1.5px solid var(--ink);display:grid;place-items:center;font-size:13px;font-weight:800}
.dn.end{background:var(--hb);border-color:transparent;border-radius:999px;text-align:center;align-items:center;justify-content:center;padding:12px 14px;font-family:var(--head);font-size:15px}
.dn.cur{box-shadow:var(--pop);transform:translate(-1px,-1px)}
.dn.end.cur{border-color:var(--ink)}
.df.tracing .dn:not(.lit){opacity:.28}
.dn .yn{display:none;gap:6px}
.dn.cur .yn{display:flex}
.yn button{
  flex:1;
  border:1.5px solid var(--ink);
  border-radius:999px;
  background:var(--panel);
  font-size:13px;
  font-weight:700;
  padding:6px 12px;
  min-height:36px;
  cursor:pointer;
  touch-action:manipulation;
}
.yn button:hover{background:var(--ink);color:var(--paper)}

/* ---------- route (sequence) ---------- */
.route{position:relative;padding:8px 0 0;width:100%}
.stops{display:flex;position:relative;z-index:1}
.stop{
  flex:1 1 0;
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:8px;
  text-align:center;
  background:none;
  border:0;
  cursor:pointer;
  padding:4px 4px;
  min-width:0;
  touch-action:manipulation;
  min-height:44px;
}
.stop .wp{width:22px;height:22px;border-radius:50%;background:var(--panel);border:2.5px solid var(--line);transition:all .3s;flex:none}
.stop.done .wp{border-color:var(--ink);background:var(--ink)}
.stop.on .wp{border-color:var(--ink);background:var(--h4);transform:scale(1.25)}
.stop.warn.on .wp{background:var(--warn-bg);border-color:var(--warn)}
.stop b{
  font-size:clamp(12px, 2vw, 14px);
  line-height:1.25;
  font-weight:700;
  overflow-wrap:break-word;
  word-break:break-word;
}
.stop>div{display:flex;flex-direction:column;align-items:center;gap:2px;min-width:0}
.stop span{
  font-size:11.5px;
  color:var(--muted);
  line-height:1.3;
  overflow-wrap:break-word;
}
.stop:not(.on) b{color:var(--muted)}
.track{position:absolute;left:0;right:0;top:51px;height:0;border-top:2.5px dashed var(--line)}
.track i{position:absolute;left:0;top:-2.5px;height:2.5px;background:var(--ink);width:0;transition:width .6s ease}
.plane{position:absolute;top:24px;left:0;width:30px;height:30px;transition:left .6s cubic-bezier(.5,0,.3,1),top .6s cubic-bezier(.5,0,.3,1);color:var(--ink);z-index:2;pointer-events:none}
.route.v .stops{flex-direction:column;gap:16px;padding-left:clamp(38px, 9vw, 48px)}
.route.v .stop{flex-direction:row;text-align:left;align-items:center;padding:4px 0;min-height:44px}
.route.v .stop>div{align-items:flex-start}
.route.v .track{left:56px;right:auto;top:0;bottom:0;border-top:0;border-left:2.5px dashed var(--line);width:0;height:auto}
.route.v .track i{width:2.5px;height:0;left:-2.5px;top:0;transition:height .6s ease}
.route.v .plane{left:0}
.route.v .plane svg{transform:rotate(90deg)}
.route-ctl{display:flex;gap:8px;margin-top:20px;flex-wrap:wrap;align-items:center}
@media (max-width:480px){
  .route-ctl .pill{flex:1;justify-content:center;padding:8px 10px;font-size:13px}
}

/* ---------- altitude (layers) ---------- */
.alt{display:grid;grid-template-columns:84px 44px minmax(0,1fr);gap:0 8px;width:100%}
.alt .lab{font-family:var(--mono);font-size:12px;color:var(--muted);text-align:right;padding-top:6px}
.alt .lane{position:relative}
.alt .lane .plane{left:6px;top:0;transition:top .55s cubic-bezier(.5,0,.3,1)}
.alt .band{
  border:0;
  border-radius:14px;
  margin-bottom:6px;
  padding:12px 16px;
  text-align:left;
  cursor:pointer;
  background:var(--hb);
  color:var(--ink);
  transition:transform .2s,box-shadow .2s;
  display:flex;
  flex-direction:column;
  min-width:0;
  touch-action:manipulation;
}
.alt .band b{font-size:15px;overflow-wrap:break-word}
.alt .band span{font-size:13px;color:var(--muted);overflow-wrap:break-word}
.alt .band.on{box-shadow:var(--pop);transform:translate(-1px,-1px);outline:1.5px solid var(--ink)}
.alt .gnd{grid-column:3;height:10px;border-radius:999px;background:repeating-linear-gradient(90deg,var(--ink) 0 10px,transparent 10px 16px);opacity:.6;margin-top:2px}
@media (max-width:480px){
  .alt{grid-template-columns:64px 34px minmax(0,1fr);gap:0 6px}
  .alt .lab{font-size:11px}
  .alt .band{padding:10px 12px;margin-bottom:5px}
  .alt .band b{font-size:14px}
  .alt .band span{font-size:12.5px}
  .alt .plane{width:24px;height:24px}
}

/* ---------- rings ---------- */
.rings{display:grid;grid-template-columns:minmax(0,320px) minmax(0,1fr);gap:clamp(16px, 3vw, 28px);align-items:center;width:100%}
@media (max-width:760px){.rings{grid-template-columns:1fr}}
.rings svg{width:100%;height:auto;max-width:320px;margin-inline:auto;display:block}
.rings circle{cursor:pointer;transition:stroke-width .2s}
.rings circle.on{stroke:var(--ink)!important;stroke-width:3}
.rings ul{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:8px}
.rings li{
  display:grid;
  grid-template-columns:16px 1fr;
  gap:12px;
  padding:10px 12px;
  border-radius:14px;
  cursor:pointer;
  transition:background .2s;
  min-height:44px;
  touch-action:manipulation;
}
.rings li.on{background:var(--wash)}
.rings li i{width:16px;height:16px;border-radius:50%;margin-top:3px;background:var(--hb);border:1.5px solid var(--hi);flex:none}
.rings li span{display:block;color:var(--muted);font-size:13.5px}

/* ---------- table ---------- */
table.mx{border-collapse:separate;border-spacing:0 6px;width:100%;min-width:540px;font-size:14px}
.mx th,.mx td{padding:10px 13px;text-align:left;vertical-align:top}
.mx thead th{font-size:11.5px;letter-spacing:.1em;text-transform:uppercase;color:var(--faint);font-weight:700;padding-block:2px 4px}
.mx tbody tr{background:var(--wash);transition:background .2s}
.mx tbody tr:hover{background:var(--hb)}
.mx tbody td:first-child,.mx tbody th:first-child{border-radius:12px 0 0 12px}
.mx tbody td:last-child{border-radius:0 12px 12px 0}
.mx tbody th{font-weight:700;white-space:nowrap}
.mx tbody th span{display:inline-block;padding:2px 10px;border-radius:999px;background:var(--hb);color:var(--hi);font-size:13px}
.mx td[data-tipped]{cursor:help;text-decoration:underline dotted var(--faint);text-underline-offset:3px}
.mx .k{display:inline-block;background:var(--panel);border:1.5px solid var(--ink);border-radius:8px;padding:1px 8px;font-weight:700}
.mx .w{display:inline-block;background:var(--warn-bg);color:var(--warn);border-radius:8px;padding:1px 8px;font-weight:700}
@media (max-width:540px){
  table.mx{min-width:440px;font-size:13px}
  .mx th,.mx td{padding:8px 10px}
}

/* ---------- decoder ---------- */
.code{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin-bottom:20px}
.code button{
  font-family:var(--mono);
  font-size:clamp(22px,5.5vw,44px);
  font-weight:700;
  border:1.5px solid transparent;
  background:var(--hb);
  color:var(--hi);
  border-radius:14px;
  padding:7px 16px;
  cursor:pointer;
  transition:transform .2s,box-shadow .2s;
  touch-action:manipulation;
}
.code button.on{border-color:var(--ink);box-shadow:var(--pop);transform:translate(-2px,-3px)}
.keys{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%, 200px),1fr));gap:10px}
.keys div{padding:12px 14px;border-radius:14px;background:var(--wash);border:1.5px solid transparent;transition:all .2s;cursor:pointer;min-height:44px;touch-action:manipulation}
.keys div.on{background:var(--hb);border-color:var(--ink)}
.keys b{font-family:var(--mono);background:var(--hb);color:var(--hi);border-radius:6px;padding:0 7px;margin-right:8px}
.keys p{font-size:13.5px;color:var(--muted);margin-top:4px}

/* ---------- numbers ---------- */
.nums{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%, 160px),1fr));gap:12px}
.num{
  border:0;
  text-align:left;
  background:var(--hb);
  border-radius:18px;
  padding:14px 16px;
  display:flex;
  flex-direction:column;
  gap:6px;
  cursor:default;
  min-height:110px;
  transition:transform .2s;
  position:relative;
  touch-action:manipulation;
}
.num:hover{transform:translateY(-3px)}
.num .ico{color:var(--hi);width:20px;height:20px}
.num .v{font-family:var(--head);font-size:22px;font-weight:700;line-height:1.1;color:var(--ink);transition:filter .3s,opacity .3s}
.num .k{font-size:13.5px;font-weight:600;line-height:1.3;overflow-wrap:break-word}
.num .n{font-size:12px;color:var(--muted);line-height:1.3;overflow-wrap:break-word}
.nums.quiz .num{cursor:pointer}
.nums.quiz .num:not(.shown) .v{filter:blur(9px);opacity:.5}
.nums.quiz .num:not(.shown)::after{content:'tap to reveal';position:absolute;right:12px;top:14px;font-size:11px;color:var(--hi);font-weight:700}

/* ---------- pairs ---------- */
.pairs{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,440px),1fr));gap:16px;width:100%}
.pair{display:flex;flex-direction:column;gap:0;min-width:0}
.vs{display:grid;grid-template-columns:1fr 1fr;gap:8px;position:relative;width:100%}
.side{border-radius:18px;padding:16px;background:var(--hb);min-height:96px;min-width:0}
.side b{display:block;font-family:var(--head);font-size:17px;color:var(--hi);margin-bottom:3px;line-height:1.2;overflow-wrap:break-word}
.side p{font-size:13.5px;color:var(--ink);opacity:.85;overflow-wrap:break-word}
.vs::after{
  content:'vs';
  position:absolute;
  left:50%;
  top:50%;
  transform:translate(-50%,-50%);
  width:32px;
  height:32px;
  border-radius:50%;
  background:var(--ink);
  color:var(--paper);
  display:grid;
  place-items:center;
  font-size:11.5px;
  font-weight:800;
  font-family:var(--head);
  z-index:2;
}
.tell{margin:-6px 14px 0;background:var(--panel);border:1.5px solid var(--ink);border-radius:14px;padding:9px 14px;font-size:13.5px;position:relative;box-shadow:var(--pop)}
.tell b{margin-right:6px}

@media (max-width:520px){
  .vs{grid-template-columns:1fr;gap:14px}
  .side{padding:14px;min-height:auto}
  .vs::after{position:static;transform:none;margin:-6px auto;width:28px;height:28px;font-size:11px}
  .tell{margin:8px 6px 0;padding:8px 12px;font-size:13px}
}

/* ---------- quiz ---------- */
.quizbox{max-width:720px;display:flex;flex-direction:column;gap:16px;width:100%}
.qbar{display:flex;gap:6px}
.qbar i{flex:1;height:6px;border-radius:999px;background:var(--line)}
.qbar i.ok{background:var(--h1i)}.qbar i.no{background:var(--warn)}.qbar i.cur{background:var(--ink)}
.qq{
  font-family:var(--head);
  font-size:clamp(18px, 4.5vw, 22px);
  line-height:1.3;
  font-weight:600;
  overflow-wrap:break-word;
}
.opts{display:flex;flex-direction:column;gap:8px}
.opt{
  border:1.5px solid var(--line);
  background:var(--panel);
  border-radius:14px;
  padding:12px 14px;
  text-align:left;
  cursor:pointer;
  font-size:15px;
  display:flex;
  gap:12px;
  align-items:center;
  transition:all .15s;
  min-height:48px;
  touch-action:manipulation;
  overflow-wrap:break-word;
}
.opt i{font-style:normal;width:28px;height:28px;border-radius:50%;background:var(--wash);display:grid;place-items:center;font-weight:700;font-size:13px;flex:none}
.opt:hover:not([disabled]){border-color:var(--ink);transform:translate(-1px,-1px);box-shadow:var(--pop)}
.opt.ok{background:var(--h1);border-color:var(--h1i)}.opt.ok i{background:var(--h1i);color:var(--h1)}
.opt.no{background:var(--warn-bg);border-color:var(--warn)}.opt.no i{background:var(--warn);color:var(--warn-bg)}
.opt[disabled]{cursor:default}
.why{background:var(--wash);border-radius:14px;padding:12px 16px;font-size:14.5px;animation:pop .3s both;line-height:1.45}
.score{font-family:var(--head);font-size:clamp(32px, 6vw, 42px);font-weight:700}

/* ---------- tooltip ---------- */
#tip{
  position:fixed;
  z-index:9999;
  max-width:min(300px, calc(100vw - 32px));
  background:var(--tip-bg);
  color:var(--tip-fg);
  padding:10px 13px;
  border-radius:12px;
  font-size:13.5px;
  line-height:1.45;
  box-shadow:0 12px 32px rgba(0,0,0,.22);
  pointer-events:none;
  display:none;
  overflow-wrap:break-word;
  word-break:break-word;
}
#tip b{display:block;margin-bottom:2px}

/* ---------- foot ---------- */
details.teacher{color:var(--muted);font-size:14px;background:var(--panel);border-radius:18px;padding:14px 18px}
details.teacher summary{cursor:pointer;font-weight:600}
details.teacher ul{margin:10px 0 0;padding-left:18px;display:flex;flex-direction:column;gap:6px}
details.teacher h4{margin:14px 0 0;font-size:13px;color:var(--ink)}
.pager{display:grid;grid-template-columns:1fr 1fr;gap:12px;width:100%}
.pager a{
  text-decoration:none;
  background:var(--panel);
  border-radius:18px;
  padding:16px 18px;
  box-shadow:var(--shadow);
  transition:transform .2s;
  min-height:56px;
  touch-action:manipulation;
}
.pager a:hover{transform:translateY(-3px)}
.pager a span{font-size:12.5px;color:var(--faint)}
.pager a b{display:block;font-family:var(--head);font-size:16px;line-height:1.25;overflow-wrap:break-word}
@media (max-width:480px){
  .pager{grid-template-columns:1fr;gap:10px}
  .pager a{padding:14px 16px}
}

/* ---------- index ---------- */
.ix-hero{
  display:grid;
  grid-template-columns:minmax(0,1fr) minmax(200px, 300px);
  gap:clamp(18px, 3vw, 28px);
  align-items:center;
  margin-bottom:28px;
  width:100%;
}
@media (max-width:760px){.ix-hero{grid-template-columns:1fr}.ix-hero .hero-art{display:none}}
.ix-search{
  width:100%;
  max-width:440px;
  padding:12px 18px;
  border-radius:999px;
  border:1.5px solid var(--ink);
  background:var(--panel);
  color:var(--ink);
  font:inherit;
  font-size:16px !important; /* Prevents auto-zoom on iOS */
  min-height:46px;
  box-shadow:var(--pop);
  box-sizing:border-box;
}
.part{margin-top:36px;width:100%}
.part h2{font-family:var(--head);font-size:clamp(22px, 3.5vw, 26px);margin:0 0 14px}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%, 250px),1fr));gap:14px;width:100%}
.card{
  background:var(--panel);
  border-radius:22px;
  padding:18px;
  text-decoration:none;
  display:flex;
  flex-direction:column;
  gap:10px;
  box-shadow:var(--shadow);
  transition:transform .2s,box-shadow .2s;
  position:relative;
  overflow:hidden;
  min-height:180px;
  min-width:0;
  touch-action:manipulation;
}
.card:hover{transform:translate(-2px,-3px);box-shadow:var(--pop);outline:1.5px solid var(--ink)}
.card .top{display:flex;justify-content:space-between;align-items:center}
.card .no{font-family:var(--head);font-size:32px;font-weight:700;color:var(--hi);line-height:1}
.card .ic{width:42px;height:42px;border-radius:14px;background:var(--hb);color:var(--hi);display:grid;place-items:center}
.card .ic .ico{width:22px;height:22px}
.card h3{margin:0;font-family:var(--head);font-size:18.5px;line-height:1.2;overflow-wrap:break-word}
.card p{color:var(--muted);font-size:13.5px;line-height:1.4;overflow-wrap:break-word}
.card-foot{margin-top:auto;padding-top:12px;border-top:1px solid var(--line);display:flex;align-items:center;gap:10px}
.cf-meta{display:flex;flex-wrap:wrap;align-items:center;gap:4px 14px;min-width:0;font-size:12.5px;font-weight:600;line-height:1.3}
.cf-free{display:inline-flex;align-items:center;gap:6px;color:var(--muted);white-space:nowrap}
.cf-free::before{content:"";width:7px;height:7px;border-radius:50%;background:var(--h1i);opacity:.55}
.cf-free.full{color:var(--h1i)}.cf-free.full::before{opacity:1}
.cf-exam{display:inline-flex;align-items:center;gap:5px;color:var(--muted);white-space:nowrap}
.cf-exam i{font-style:normal;font-size:10px;color:var(--exam-gold)}
.cf-lock{display:inline-grid;place-items:center;color:var(--exam-ink);margin-left:1px}
.cf-lock .ico{width:13px;height:13px;stroke-width:2.4}
.cf-go{margin-left:auto;flex:none;width:30px;height:30px;border-radius:50%;display:grid;place-items:center;background:var(--wash);color:var(--ink);font-size:15px;font-weight:700;transition:background .15s,color .15s,transform .15s}
.card:hover .cf-go{background:var(--ink);color:var(--paper);transform:translateX(2px)}
.cf-go.done{background:var(--h1);color:var(--h1i)}
.card:hover .cf-go.done{background:var(--h1);color:var(--h1i);transform:none}
.card.off{opacity:.5;pointer-events:none;box-shadow:none;background:transparent;border:1.5px dashed var(--line)}
@media (max-width:360px){
  .cards{grid-template-columns:1fr;gap:10px}
  .card{padding:14px;min-height:auto}
}

@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}

/* book definitions */
blockquote.book{margin:8px 0 0;padding:8px 12px;border-left:3px solid var(--hi,var(--ink));background:var(--panel);border-radius:0 10px 10px 0;font-size:13.5px;line-height:1.5;color:var(--ink);font-style:italic;overflow-wrap:break-word}
blockquote.book span{display:block;font-style:normal;font-size:10.5px;letter-spacing:.12em;text-transform:uppercase;font-weight:700;color:var(--faint);margin-bottom:2px}
#tip em{display:block;margin-top:6px;opacity:.8;font-size:12.5px}
.keys .kq{font-style:italic;font-size:13px;margin-top:6px;color:var(--ink);opacity:.8;overflow-wrap:break-word}

/* ---------- auth & payment modals ---------- */
.atlas-modal-backdrop{
  position:fixed;
  inset:0;
  background:rgba(15,18,24,.68);
  backdrop-filter:blur(8px);
  -webkit-backdrop-filter:blur(8px);
  z-index:9000;
  display:grid;
  place-items:center;
  padding:max(12px, env(safe-area-inset-top)) max(12px, env(safe-area-inset-right)) max(12px, env(safe-area-inset-bottom)) max(12px, env(safe-area-inset-left));
  animation:atlasFadeIn .2s ease-out;
  overflow-y:auto;
}
@keyframes atlasFadeIn{from{opacity:0}to{opacity:1}}
.atlas-modal{
  background:var(--panel);
  color:var(--ink);
  border:1.5px solid var(--ink);
  border-radius:24px;
  box-shadow:0 24px 60px rgba(0,0,0,.35),var(--pop);
  width:100%;
  max-width:480px;
  padding:clamp(20px, 4vw, 28px) clamp(16px, 4vw, 24px) 20px;
  position:relative;
  animation:atlasModalPop .24s cubic-bezier(.16,1,.3,1);
  box-sizing:border-box;
  max-height:calc(100dvh - 24px);
  overflow-y:auto;
}
@keyframes atlasModalPop{from{opacity:0;transform:scale(.95) translateY(10px)}to{opacity:1;transform:scale(1) translateY(0)}}
.atlas-modal-close{
  position:absolute;
  top:14px;
  right:14px;
  width:36px;
  height:36px;
  border-radius:50%;
  border:1px solid var(--line);
  background:var(--wash);
  color:var(--muted);
  display:grid;
  place-items:center;
  cursor:pointer;
  font-size:18px;
  line-height:1;
  transition:all .12s;
  touch-action:manipulation;
}
.atlas-modal-close:hover{color:var(--ink);background:var(--panel);border-color:var(--ink);transform:scale(1.05)}
.atlas-modal-head{display:flex;flex-direction:column;gap:6px;margin-bottom:18px}
.atlas-modal-head h3{margin:0;font-family:var(--head);font-size:clamp(20px, 4vw, 24px);line-height:1.2;font-weight:700;letter-spacing:-.01em;overflow-wrap:break-word}
.atlas-modal-head p{font-size:13.5px;color:var(--muted);line-height:1.45;overflow-wrap:break-word}
.atlas-tabs{display:flex;gap:6px;padding:4px;border-radius:14px;background:var(--wash);margin-bottom:18px}
.atlas-tab{
  flex:1;
  padding:8px 10px;
  border:none;
  background:transparent;
  border-radius:10px;
  font-size:13px;
  font-weight:700;
  font-family:var(--head);
  cursor:pointer;
  color:var(--muted);
  transition:all .15s;
  min-height:38px;
  touch-action:manipulation;
}
.atlas-tab.active{background:var(--panel);color:var(--ink);box-shadow:0 1px 3px rgba(0,0,0,.1)}
.atlas-form{display:flex;flex-direction:column;gap:14px;width:100%}

.atlas-pw-wrap {
  position: relative;
  display: flex;
  align-items: center;
  width: 100%;
}
.atlas-pw-wrap .atlas-input {
  padding-right: 44px;
}
.atlas-pw-toggle {
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  padding: 6px;
  cursor: pointer;
  color: var(--muted);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  transition: color 0.15s, background-color 0.15s;
  touch-action: manipulation;
}
.atlas-pw-toggle:hover {
  color: var(--ink);
  background: var(--wash);
}
.atlas-pw-toggle .ico {
  width: 19px;
  height: 19px;
}
.atlas-field{display:flex;flex-direction:column;gap:5px}
.atlas-field label{font-size:11.5px;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:var(--muted)}
.atlas-input{
  width:100%;
  padding:11px 14px;
  border:1.5px solid var(--line);
  border-radius:12px;
  background:var(--wash);
  color:var(--ink);
  font-family:var(--font);
  font-size:16px !important; /* Prevents auto-zoom on iOS Safari */
  min-height:44px;
  transition:border-color .15s;
  box-sizing:border-box;
}
.atlas-input:focus{outline:none;border-color:var(--ink);background:var(--panel)}
.atlas-input.mono{font-family:var(--mono);letter-spacing:.05em}
.atlas-btn{
  width:100%;
  padding:12px 18px;
  border:1.5px solid var(--ink);
  border-radius:14px;
  font-family:var(--head);
  font-weight:700;
  font-size:14.5px;
  cursor:pointer;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  box-shadow:var(--pop);
  transition:transform .12s,box-shadow .12s;
  text-decoration:none;
  min-height:44px;
  touch-action:manipulation;
  box-sizing:border-box;
}
.atlas-btn:hover:not([disabled]){transform:translate(-1px,-1px);box-shadow:4px 4px 0 var(--ink)}
.atlas-btn:active:not([disabled]){transform:translate(1px,1px);box-shadow:1px 1px 0 var(--ink)}
.atlas-btn[disabled]{opacity:.55;cursor:not-allowed;box-shadow:none}
.atlas-btn-primary{background:var(--ink);color:var(--paper)}
.atlas-btn-accent{background:var(--accent);color:#ffffff;border-color:var(--ink)}
.atlas-btn-soft{background:var(--wash);border-color:var(--line);box-shadow:none;font-size:13px;padding:9px 14px;min-height:38px}
.atlas-btn-soft:hover:not([disabled]){box-shadow:2px 2px 0 var(--line);border-color:var(--ink)}
.atlas-error{padding:9px 12px;border-radius:10px;background:var(--warn-bg);color:var(--warn);font-size:13px;line-height:1.4;border:1px solid var(--warn);overflow-wrap:break-word}
.atlas-preset-box{margin-top:14px;padding-top:14px;border-top:1px dashed var(--line);display:flex;flex-direction:column;gap:8px}
.atlas-preset-box span{font-size:11px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--faint)}
.atlas-preset-row{display:grid;grid-template-columns:1fr 1fr;gap:8px}
@media (max-width:360px){.atlas-preset-row{grid-template-columns:1fr}}

/* ---------- upi components ---------- */
.upi-plan-selector{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:14px;width:100%}
.upi-plan-card{
  border:1.5px solid var(--line);
  background:var(--wash);
  border-radius:16px;
  padding:12px;
  text-align:left;
  cursor:pointer;
  position:relative;
  transition:all .15s;
  display:flex;
  flex-direction:column;
  gap:3px;
  touch-action:manipulation;
  min-width:0;
}
.upi-plan-card:hover{border-color:var(--ink)}
.upi-plan-card.active{border-color:var(--ink);background:var(--panel);box-shadow:var(--pop)}
.upi-plan-badge{position:absolute;top:-8px;right:10px;font-size:10px;font-weight:700;text-transform:uppercase;letter-spacing:.06em;padding:2px 7px;border-radius:999px;background:var(--h1);color:var(--h1i);white-space:nowrap}
.upi-plan-title{font-family:var(--head);font-size:13.5px;font-weight:700;color:var(--ink);overflow-wrap:break-word}
.upi-plan-cost{font-family:var(--head);font-size:20px;font-weight:800;color:var(--ink);line-height:1.1}
.upi-plan-sub{font-size:11.5px;color:var(--muted);line-height:1.2;overflow-wrap:break-word}
@media (max-width:380px){
  .upi-plan-selector{grid-template-columns:1fr;gap:8px}
  .upi-plan-card{flex-direction:row;justify-content:space-between;align-items:center;padding:10px 12px}
  .upi-plan-badge{position:static;margin-left:6px}
}

.upi-qr-card{
  background:#FFFFFF;
  color:#111318;
  padding:14px;
  border-radius:18px;
  border:1.5px solid var(--line);
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:10px;
  margin-block:10px;
  box-shadow:inset 0 0 0 1px rgba(0,0,0,.04);
  max-width:100%;
  box-sizing:border-box;
}
.upi-qr-img{width:min(220px, 58vw);height:auto;aspect-ratio:1;display:block;border-radius:8px}
.upi-qr-label{font-size:11.5px;font-family:var(--mono);color:#5F6470;display:flex;align-items:center;gap:6px;flex-wrap:wrap;justify-content:center}
.upi-vpa-pill{
  display:inline-flex;
  align-items:center;
  gap:8px;
  background:var(--wash);
  padding:6px 12px;
  border-radius:999px;
  font-family:var(--mono);
  font-size:12px;
  color:var(--ink);
  border:1px solid var(--line);
  cursor:pointer;
  transition:border-color .15s;
  touch-action:manipulation;
  word-break:break-all;
  max-width:100%;
}
.upi-vpa-pill:hover{border-color:var(--ink)}
.upi-gpay-btn{
  width:100%;
  padding:12px 16px;
  border-radius:14px;
  border:1.5px solid var(--ink);
  background:var(--panel);
  color:var(--ink);
  font-size:14px;
  font-weight:700;
  font-family:var(--head);
  text-align:center;
  text-decoration:none;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  margin-top:6px;
  margin-bottom:6px;
  box-shadow:var(--pop);
  transition:all .15s;
  cursor:pointer;
  box-sizing:border-box;
  min-height:46px;
  touch-action:manipulation;
}
.upi-gpay-btn:hover{background:var(--wash);transform:translate(-1px,-1px);box-shadow:4px 4px 0 var(--ink)}
.upi-gpay-btn:active{transform:translate(1px,1px);box-shadow:1px 1px 0 var(--ink)}
.upi-gpay-hint{font-size:12px;color:var(--muted);text-align:center;line-height:1.4;margin-bottom:10px}
.upi-price-tag{display:flex;align-items:baseline;gap:6px;margin-bottom:4px}
.upi-price-tag b{font-family:var(--head);font-size:30px;line-height:1;font-weight:800;color:var(--ink)}
.upi-price-tag span{font-size:12.5px;color:var(--muted);text-transform:uppercase;font-weight:700;letter-spacing:.05em}

/* ---------- locked lesson banner & state ---------- */
.locked-stage{
  background:var(--wash);
  border:1.5px dashed var(--line);
  border-radius:24px;
  padding:clamp(22px, 5vw, 36px) clamp(14px, 4vw, 20px);
  display:flex;
  flex-direction:column;
  align-items:center;
  text-align:center;
  gap:14px;
  position:relative;
  overflow:hidden;
  width:100%;
  box-sizing:border-box;
}
.locked-icon-badge{width:52px;height:52px;border-radius:16px;background:var(--hb,var(--h0));color:var(--hi,var(--h0i));display:grid;place-items:center;margin-bottom:2px}
.locked-icon-badge .ico{width:26px;height:26px}
.locked-stage h3{font-family:var(--head);font-size:clamp(19px, 3.5vw, 22px);margin:0;font-weight:700;color:var(--ink);overflow-wrap:break-word}
.locked-stage p{color:var(--muted);font-size:14.5px;max-width:440px;line-height:1.45;overflow-wrap:break-word}
.locked-action-group{display:flex;flex-wrap:wrap;gap:10px;justify-content:center;margin-top:6px;width:100%}
.locked-perks{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%, 180px),1fr));gap:8px;width:100%;max-width:540px;margin-top:8px;text-align:left}
.locked-perk{font-size:13px;color:var(--muted);display:flex;align-items:center;gap:7px}
.locked-perk b{color:var(--ink)}
@media (max-width:480px){
  .locked-action-group{flex-direction:column}
  .locked-action-group .atlas-btn{width:100%}
  .locked-perks{grid-template-columns:1fr}
}
.toc a.locked{opacity:.8}
.toc a.locked i{color:var(--warn)}
.toc a .lock-badge{margin-left:auto;font-size:11px;opacity:.7}
.chip-free{background:var(--h1);color:var(--h1i);font-size:11px;font-weight:700;padding:2px 7px;border-radius:999px;margin-left:6px;vertical-align:middle;white-space:nowrap}

/* ---------- auth nav & menu ---------- */
.auth-wrap{position:relative}
.auth-menu{
  position:absolute;
  top:calc(100% + 8px);
  right:0;
  width:min(280px, calc(100vw - 32px));
  background:var(--panel);
  border:1.5px solid var(--ink);
  border-radius:18px;
  box-shadow:var(--pop),0 12px 30px rgba(0,0,0,.15);
  padding:14px;
  z-index:8000;
  display:flex;
  flex-direction:column;
  gap:10px;
  animation:atlasFadeIn .15s ease-out;
  box-sizing:border-box;
}
.auth-menu-user{display:flex;flex-direction:column;gap:2px;padding-bottom:10px;border-bottom:1px solid var(--line)}
.auth-menu-name{font-family:var(--head);font-weight:700;font-size:15px;color:var(--ink);overflow-wrap:break-word}
.auth-menu-email{font-size:12px;color:var(--muted);word-break:break-all}
.auth-menu-status{display:inline-flex;align-items:center;gap:5px;font-size:11.5px;font-weight:700;color:var(--h1i);background:var(--h1);padding:3px 8px;border-radius:999px;margin-top:4px;align-self:flex-start}
.auth-menu-status.free{color:var(--num);background:var(--h4)}
/* ---------- auth: strength meter, 2FA, captcha ---------- */
.atlas-field > span { font-size: 13px; font-weight: 700; color: var(--muted); }
.atlas-ok { background: var(--h1); color: var(--h1i); border-radius: 12px; padding: 10px 12px; font-size: 13.5px; font-weight: 600; }
.atlas-link { background: none; border: 0; padding: 4px 0; color: var(--muted); font: inherit; font-size: 13px; text-decoration: underline; cursor: pointer; align-self: center; }
.atlas-link:hover { color: var(--ink); }
.atlas-captcha { min-height: 66px; }
.pw-meter { display: flex; flex-direction: column; gap: 6px; font-size: 12.5px; }
.pw-bars { display: grid; grid-template-columns: repeat(4, 1fr); gap: 4px; }
.pw-seg { height: 6px; border-radius: 3px; background: var(--line); transition: background .2s; }
.pw-seg.s0, .pw-seg.s1 { background: var(--warn); }
.pw-seg.s2 { background: var(--num); }
.pw-seg.s3, .pw-seg.s4 { background: var(--h1i); }
.pw-label { font-weight: 700; color: var(--ink); }
.pw-rules { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 4px 12px; color: var(--muted); }
.pw-rule::before { content: '○ '; }
.pw-rule.ok { color: var(--h1i); }
.pw-rule.ok::before { content: '✓ '; }
.pw-advice { color: var(--muted); }
.mfa-steps { margin: 0; padding-left: 20px; display: flex; flex-direction: column; gap: 8px; font-size: 14px; }
.mfa-secret { display: block; margin-top: 6px; font-family: var(--mono); font-size: 15px; letter-spacing: .06em; background: var(--wash); border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px; word-break: break-all; user-select: all; }
.backup-codes { columns: 2; font-family: var(--mono); font-size: 15px; margin: 0; padding-left: 26px; }

/* ================= Renderer v4: parts · hotspot · signals · timeline · scale · classify ================= */

/* ---------- parts ---------- */
.part-head{display:flex;align-items:baseline;gap:12px;margin-top:20px;padding-top:16px;border-top:1.5px solid var(--line)}
.part-head span{font-size:12px;letter-spacing:.14em;text-transform:uppercase;color:var(--faint);font-weight:700;font-family:var(--mono)}
.part-head b{font-family:var(--head);font-size:clamp(19px,2.4vw,23px);font-weight:700;line-height:1.2}
.toc-part{display:flex;flex-direction:column;gap:4px}
.toc-part-h{border:0;background:none;font-family:inherit;text-align:left;width:100%;cursor:pointer;font-size:11.5px;letter-spacing:.1em;text-transform:uppercase;font-weight:700;color:var(--faint);padding:12px 12px 4px;display:flex;gap:8px;align-items:center}
.toc-part.closed>a{display:none}
.toc-part-h i{font-style:normal;font-family:var(--mono);font-size:10.5px}
.toc-part-h::after{content:'▾';margin-left:auto;transition:transform .2s}
.toc-part.closed .toc-part-h::after{transform:rotate(-90deg)}
.toc-part-h:hover{color:var(--ink)}
.toc-part-h:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:8px}
@media (max-width:920px){
  .toc-part{display:contents}
  .toc-part-h{flex-shrink:0;width:auto;white-space:nowrap;padding:8px 6px 8px 12px;border-left:1.5px solid var(--line);margin-left:4px;pointer-events:none}
  .toc-part-h::after{content:none}
  .toc-part.closed>a{display:flex}
}

/* ---------- hotspot ---------- */
.hs{display:flex;flex-direction:column;gap:14px}
.hs-scene{background:var(--panel);border:1.5px solid var(--line);border-radius:18px;padding:8px}
.hs-scene svg{display:block;width:100%;height:auto;min-width:520px}
@media (max-width:640px){
  .svg-scene svg,.hs-scene svg{min-width:var(--mw,520px)!important}
}
.swipe-hint{margin:6px 2px 0}
.hs-pin{cursor:pointer;outline:none}
.hs-b{transform-box:fill-box;transform-origin:center;transition:transform .2s}
.hs-dot{fill:var(--ink);stroke:var(--panel);stroke-width:3}
.hs-num{fill:var(--paper);font:700 13px var(--font);pointer-events:none}
.hs-pin:hover .hs-b,.hs-pin:focus-visible .hs-b{transform:scale(1.1)}
.hs-pin.on .hs-b{transform:scale(1.15);filter:drop-shadow(3px 3px 0 var(--ink))}
.hs-pin.on .hs-dot{fill:var(--hi);stroke:var(--ink);stroke-width:2}
.hs-pin.on .hs-num{fill:var(--panel)}
.hs-pin:focus-visible .hs-dot{stroke:var(--accent);stroke-width:4}
.hs-scene [data-spot]{transition:stroke .2s,stroke-width .2s}
.hs-scene [data-spot].lit{stroke:var(--hi)!important;stroke-width:4px!important}
.hs-legend{display:flex;flex-wrap:wrap;gap:8px}
.hs-chip{display:inline-flex;align-items:center;gap:8px;border:1.5px solid transparent;background:var(--hb);color:var(--ink);border-radius:999px;padding:5px 12px 5px 5px;font:600 13.5px var(--font);cursor:pointer;min-height:34px;touch-action:manipulation}
.hs-chip i{font-style:normal;width:24px;height:24px;border-radius:50%;display:grid;place-items:center;background:var(--ink);color:var(--paper);font-size:12px;font-weight:700}
.hs-chip.on{border-color:var(--ink);box-shadow:var(--pop)}
.hs-chip b{font-weight:600;transition:filter .3s,opacity .3s}
.hs.test .hs-chip:not(.seen) b{filter:blur(6px);opacity:.55}

/* ---------- signals ---------- */
.sig-filter{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:10px}
.sig-filter .pill.on{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.sig-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,156px),1fr));gap:12px}
.sig{border:1.5px solid transparent;background:var(--hb);border-radius:18px;padding:12px;display:flex;flex-direction:column;align-items:center;gap:8px;text-align:center;cursor:pointer;color:var(--ink);font:inherit;position:relative;transition:transform .2s;touch-action:manipulation}
.sig:hover{transform:translateY(-3px)}
.sig.on{border-color:var(--ink);box-shadow:var(--pop)}
.sig[hidden]{display:none}
.sig-pic{width:100%;max-width:120px;aspect-ratio:1;border-radius:14px;background:var(--panel);display:grid;place-items:center;overflow:hidden}
.sig-pic svg{width:100%;height:100%}
.sig-name{font-size:14px;line-height:1.25;transition:filter .3s,opacity .3s}
.sig-sub{font-size:12px;color:var(--muted);line-height:1.3;transition:filter .3s,opacity .3s}
.sig-grid.test .sig:not(.shown) .sig-name,.sig-grid.test .sig:not(.shown) .sig-sub{filter:blur(7px);opacity:.5}
.sig-grid.test .sig:not(.shown)::after{content:'tap to reveal';position:absolute;top:8px;right:10px;font-size:10.5px;font-weight:700;color:var(--hi)}

/* ---------- timeline ---------- */
.tl-wrap{padding:6px 4px 0}
.tl{position:relative;height:calc(104px + var(--lanes,1) * 66px);margin-inline:6px}
.tl-axis{position:absolute;left:0;right:0;top:36px;height:3px;border-radius:3px;background:var(--ink)}
.tl-tick{position:absolute;top:0;left:calc(var(--p) * 1%);height:44px;border-left:1.5px solid var(--wire)}
.tl-tick span{position:absolute;top:0;left:0;transform:translateX(calc(var(--p) * -1%));white-space:nowrap;font:700 12px var(--mono);color:var(--num);padding-inline:4px}
.tl-band{position:absolute;z-index:1;top:46px;height:30px;left:calc(var(--a) * 1%);width:calc((var(--b) - var(--a)) * 1%);background:var(--hb);border:1.5px dashed var(--hi);border-radius:10px;display:flex;align-items:center;justify-content:center;overflow:hidden;cursor:default}
.tl-band span{font-size:12px;font-weight:700;color:var(--hi);white-space:nowrap;padding-inline:6px;display:flex;gap:6px;align-items:baseline}
.tl-band small{font:600 11px var(--mono);opacity:.85}
.tl-band.tl-tight small{display:none}
.tl-band.tl-tighter span{visibility:hidden}
.tl-dot{position:absolute;top:36px;left:calc(var(--p) * 1%);height:calc(46px + var(--lane) * 66px);border-left:2px dashed var(--hi);opacity:0;transition:opacity .4s calc(var(--lane) * 80ms)}
.tl-dot::before{content:'';position:absolute;top:-6px;left:-8px;width:14px;height:14px;border-radius:50%;background:var(--hi);border:2.5px solid var(--panel)}
.tl-mark{position:absolute;top:calc(82px + var(--lane) * 66px);left:calc(var(--p) * 1%);transform:translate(calc(var(--p) * -1%),10px);opacity:0;
  z-index:1;display:flex;flex-direction:column;align-items:flex-start;gap:2px;width:max-content;max-width:min(220px,46%);text-align:left;padding:7px 12px;border-radius:14px;border:1.5px solid transparent;background:var(--hb);color:var(--ink);font:inherit;cursor:pointer;
  transition:opacity .45s calc(var(--i) * 90ms),transform .45s calc(var(--i) * 90ms),box-shadow .2s;touch-action:manipulation}
.tl-mark b{font-size:13.5px;line-height:1.25}
.tl-at{font:700 12px var(--mono);color:var(--num)}
.tl.in .tl-mark{opacity:1;transform:translate(calc(var(--p) * -1%),0)}
.tl.in .tl-dot{opacity:1}
.tl-mark:hover,.tl-mark:focus-visible{box-shadow:var(--pop)}
.tl-mark.on{border-color:var(--ink);box-shadow:var(--pop)}
@media (max-width:640px){
  /* Vertical on phones: an ordered rail instead of proportional placement, so text stays readable. */
  .tl{height:auto;display:flex;flex-direction:column;gap:10px;padding-left:26px;margin:0}
  .tl-axis{top:4px;bottom:4px;left:8px;right:auto;width:3px;height:auto}
  .tl-tick,.tl-dot{display:none}
  .tl-band,.tl-mark{position:relative;top:auto;left:auto;width:auto;max-width:100%;order:var(--o)}
  .tl-mark{transform:translateY(8px)}
  .tl.in .tl-mark{transform:none}
  .tl-mark::before,.tl-band::before{content:'';position:absolute;left:-24px;top:12px;width:12px;height:12px;border-radius:50%;background:var(--hi);border:2.5px solid var(--panel)}
  .tl-band{height:auto;padding:8px 12px;justify-content:flex-start;overflow:visible}
}

/* ---------- scale ---------- */
.scale{display:flex;flex-direction:column;gap:8px}
.sc-row{display:grid;grid-template-columns:minmax(120px,34%) 1fr auto;align-items:center;gap:12px;padding:8px 12px;border-radius:14px;border:1.5px solid transparent;background:transparent;color:var(--ink);font:inherit;text-align:left;cursor:pointer;touch-action:manipulation}
.sc-row:hover{background:var(--wash)}
.sc-row.on{border-color:var(--ink);background:var(--panel);box-shadow:var(--pop)}
.sc-label{font-size:14px;font-weight:600;line-height:1.3;display:flex;flex-direction:column}
.sc-label small{font-size:12px;font-weight:500;color:var(--muted)}
.sc-track{height:16px;border-radius:999px;background:var(--wash);overflow:hidden}
.sc-bar{display:block;height:100%;width:0;border-radius:999px;background:var(--hi);transition:width .8s cubic-bezier(.2,.8,.2,1) calc(var(--i) * 70ms)}
.scale.grown .sc-bar{width:calc(var(--w) * 1%)}
.sc-v{font:700 14px var(--mono);color:var(--num);min-width:64px;text-align:right;transition:filter .3s,opacity .3s}
.scale.test .sc-row:not(.shown) .sc-v{filter:blur(7px);opacity:.5}
@media (max-width:520px){
  .sc-row{grid-template-columns:1fr auto;grid-template-areas:'l v' 't t'}
  .sc-label{grid-area:l}.sc-v{grid-area:v}.sc-track{grid-area:t}
}

/* ---------- classify ---------- */
.cls{display:flex;flex-direction:column;gap:14px}
.cls-pool{display:flex;flex-wrap:wrap;gap:8px;min-height:44px;padding:12px;border:1.5px dashed var(--wire);border-radius:16px;background:var(--wash)}
.cls-pool:empty::before{content:'All sorted.';color:var(--muted);font-size:14px;align-self:center}
.cls-chip{border:1.5px solid var(--line);background:var(--panel);color:var(--ink);border-radius:999px;padding:8px 14px;font:600 14px var(--font);cursor:pointer;min-height:38px;touch-action:manipulation;transition:transform .15s}
.cls-chip:hover{transform:translateY(-2px)}
.cls-chip.on{background:var(--ink);color:var(--paper);border-color:var(--ink);box-shadow:var(--pop)}
.cls-say{font-size:14.5px;color:var(--muted);min-height:22px}
.cls-say b{color:var(--ink)}
.cls-buckets{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,200px),1fr));gap:12px}
.cls-bucket{display:flex;flex-direction:column;align-items:flex-start;gap:8px;min-height:130px;padding:14px;border-radius:18px;border:1.5px solid transparent;background:var(--hb);color:var(--ink);font:inherit;text-align:left;cursor:pointer;touch-action:manipulation}
.cls-bucket:hover,.cls-bucket:focus-visible{border-color:var(--ink)}
.cls-bucket>b{font-family:var(--head);font-size:17px;color:var(--hi)}
.cls-bucket>span{font-size:12.5px;color:var(--muted)}
.cls-in{display:flex;flex-direction:column;gap:6px;width:100%}
.cls-done{display:flex;align-items:center;gap:6px;font-size:13px;font-weight:600;background:var(--panel);border-radius:10px;padding:5px 9px}
.cls-done .ico{width:15px;height:15px;color:var(--h1i)}
.cls-bucket.shake{animation:shake .4s}
@keyframes shake{20%,60%{transform:translateX(-6px)}40%,80%{transform:translateX(6px)}}
.cls-end{display:flex;align-items:center;gap:12px;flex-wrap:wrap}


/* ================= Study tracks: Core & Revision vs Exam-Ready ================= */
.track-switch{display:grid;grid-template-columns:1fr 1fr;gap:6px;padding:6px;border-radius:16px;background:var(--wash);margin-bottom:10px}
.trk{display:flex;flex-direction:column;align-items:flex-start;gap:2px;padding:9px 11px;border-radius:12px;border:1.5px solid transparent;background:transparent;color:var(--ink);font:inherit;text-align:left;cursor:pointer;touch-action:manipulation;transition:background .2s,border-color .2s,box-shadow .2s}
.trk b{font-size:13px;line-height:1.2}
.trk small{font-size:11px;color:var(--muted)}
.trk:hover{background:var(--panel)}
.trk:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.trk-core.on{background:var(--h1);border-color:var(--h1i)}
.trk-core.on b{color:var(--h1i)}
.trk-exam b{font-family:var(--head);font-weight:700}
.trk-exam.on{background:var(--exam-bg);border-color:var(--exam-gold);box-shadow:var(--pop)}
.trk-exam.on b{color:var(--exam-fg)}
.trk-exam.on small{color:var(--exam-dim)}

/* Exam-Ready sidebar: clean warm pastel card with gold accents, matching site layout. */
.toc.track-exam{background:var(--exam-bg);color:var(--exam-fg);border:1.5px solid var(--exam-line);border-radius:20px;padding:10px;animation:examIn .35s ease-out both}
.toc.track-exam .track-switch{background:var(--exam-panel);border:1px solid var(--exam-line)}
.toc.track-exam .trk-core{color:var(--exam-dim)}
.toc.track-exam .trk-core:hover{background:var(--exam-line)}
.toc.track-exam a{color:var(--exam-dim)}
.toc.track-exam a i{color:var(--exam-dim)}
.toc.track-exam a.toc-exam{color:var(--exam-fg);font-weight:600}
.toc.track-exam a.toc-exam i{color:var(--exam-gold);font-size:12px}
.toc.track-exam a:hover{background:var(--exam-panel);color:var(--exam-fg)}
.toc.track-exam a.on{background:var(--exam-panel);color:var(--exam-fg);border:1.5px solid var(--exam-gold);box-shadow:var(--pop)}
.toc.track-exam a.on i{color:var(--exam-gold)}
.toc.track-exam .toc-part-h{color:var(--exam-gold);font-weight:700}
.toc.track-exam .chip-free{background:var(--h1);color:var(--h1i)}
@keyframes examIn{from{opacity:.4;transform:translateY(6px)}to{opacity:1;transform:none}}

.toc-teaser{margin-top:10px;display:flex;flex-direction:column;align-items:flex-start;gap:3px;padding:12px 14px;border-radius:14px;border:1.5px dashed var(--exam-gold);background:var(--exam-bg);color:var(--exam-fg);font:inherit;text-align:left;cursor:pointer;touch-action:manipulation;transition:transform .2s}
.toc-teaser b{font-family:var(--head);color:var(--exam-fg);font-size:13px}
.toc-teaser span{font-size:12.5px;color:var(--exam-dim)}
.toc-teaser:hover{transform:translateY(-2px)}

.track-chip{margin-left:6px}
.track-chip-core{background:var(--h1);color:var(--h1i)}
.track-chip-exam{background:var(--exam-bg);color:var(--exam-fg);border:1px solid var(--exam-line);font-family:var(--head);font-weight:700}

/* Exam-Ready lessons in the page: a warm pastel ribbon and badge */
.exam-ribbon{display:inline-flex;align-items:center;gap:6px;font:700 11px var(--head);text-transform:uppercase;letter-spacing:.08em;background:var(--exam-bg);color:var(--exam-fg);border:1px solid var(--exam-line);padding:3px 9px;border-radius:6px;margin-bottom:6px}
.lesson.exam .lh .badge{background:var(--exam-bg);color:var(--exam-fg);border:1.5px solid var(--exam-gold)}
.locked-stage.locked-exam{background:var(--exam-bg);color:var(--exam-fg);border:1.5px solid var(--exam-line)}
.locked-stage.locked-exam h3{color:var(--exam-fg)}
.locked-stage.locked-exam p{color:var(--exam-dim)}
.locked-stage.locked-exam .locked-icon-badge{background:var(--exam-panel);color:var(--exam-gold);border:1.5px solid var(--exam-line)}
.locked-lead{font-style:italic}
.atlas-btn-exam{background:var(--exam-gold);color:#1A1305;border-color:var(--ink);box-shadow:var(--pop)}
.atlas-btn-exam:hover{background:#DCA21D;transform:translate(-1px,-1px)}

/* Subscription picker in the payment modal */
.sub-tier-row{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:12px}
.sub-tier{display:flex;flex-direction:column;align-items:flex-start;gap:4px;padding:12px 14px;border-radius:14px;border:1.5px solid var(--line);background:var(--panel);color:var(--ink);font:inherit;text-align:left;cursor:pointer;touch-action:manipulation;transition:all .15s}
.sub-tier-name{font-weight:700;font-size:14px}
.sub-tier-sub{font-size:12px;color:var(--muted);line-height:1.35}
.sub-core.active{border-color:var(--h1i);background:var(--h1);box-shadow:var(--pop)}
.sub-exam.active{border-color:var(--exam-gold);background:var(--exam-bg);color:var(--exam-fg);box-shadow:var(--pop)}
.sub-exam .sub-tier-name{font-family:var(--head);font-weight:700}
.sub-exam.active .sub-tier-name{color:var(--exam-fg)}
.sub-exam.active .sub-tier-sub{color:var(--exam-dim)}
@media (max-width:480px){.sub-tier-row{grid-template-columns:1fr}}

@media (max-width:920px){
  /* On phones the sidebar is a horizontal pill bar: the switch becomes its first two pills. */
  .track-switch{display:flex;flex-shrink:0;padding:3px;margin:0 6px 0 0;border-radius:999px}
  .trk{flex-direction:row;align-items:center;gap:6px;padding:6px 12px;border-radius:999px;white-space:nowrap}
  .trk small{display:none}
  .trk-exam.on{box-shadow:none}
  .toc.track-exam{border-radius:999px;padding:8px 6px;background:var(--exam-bg)!important;border-color:var(--exam-line)}
  .toc-teaser{flex-direction:row;align-items:center;flex-shrink:0;margin:0 0 0 6px;padding:6px 12px;border-radius:999px;white-space:nowrap}
  .toc-teaser span{display:none}
}
.chip-exam{font:700 11px var(--head);letter-spacing:.02em;background:var(--exam-bg);color:var(--exam-fg);border:1px solid var(--exam-line);padding:3px 9px;border-radius:999px;white-space:nowrap}

/* Story animations inside lesson pictures (spec SVG uses these classes; reduced motion turns them off) */
.fx-flash{animation:fxFlash 1s steps(1,end) infinite}
.fx-seq{animation:fxSeq .5s linear infinite;animation-delay:calc(var(--d,0) * .016s)}
.fx-beacon{animation:fxFlash 2.4s steps(1,end) infinite}
.fx-pulse{animation:fxPulse 1.6s ease-in-out infinite;transform-box:fill-box;transform-origin:center}
.fx-drive{animation:fxDrive 4s ease-in-out infinite alternate}
@keyframes fxFlash{0%{opacity:1}50%{opacity:.15}}
@keyframes fxSeq{0%,18%{opacity:1}22%,100%{opacity:.18}}
@keyframes fxPulse{0%,100%{transform:scale(1);opacity:1}50%{transform:scale(1.35);opacity:.6}}
@keyframes fxDrive{from{transform:translateX(0)}to{transform:translateX(var(--dx,120px))}}
.fx-beacon.alt{animation-delay:-1.2s}

/* Consent tick box (sign-up and payment) and controls that became real buttons for keyboard users. */
.atlas-consent{display:flex;gap:10px;align-items:flex-start;font-size:13.5px;line-height:1.45;color:var(--ink);cursor:pointer}
.atlas-consent a{color:var(--accent);font-weight:600;text-decoration:underline;text-underline-offset:2px}
.atlas-check{flex:none;width:20px;height:20px;margin:1px 0 0;accent-color:var(--ink);cursor:pointer}
.upi-plan-card,.upi-vpa-pill{font:inherit;color:inherit}
.upi-vpa-pill{font-family:var(--mono);font-size:12px;color:var(--ink)}
button.upi-gpay-btn{cursor:pointer}

/* Skip link, site footer and the static legal pages. */
.skip{position:absolute;left:12px;top:-60px;z-index:99;background:var(--ink);color:var(--paper);padding:10px 14px;border-radius:10px;font-weight:700;text-decoration:none}
.skip:focus{top:12px}
.site-foot{margin:48px auto 0;padding:22px 0 30px;border-top:1px solid var(--line);color:var(--muted);font-size:13px;line-height:1.6;display:flex;flex-direction:column;gap:6px;max-width:1240px;width:100%}
.site-foot nav{display:flex;flex-wrap:wrap;gap:6px 18px;font-weight:600}
.site-foot a{color:var(--ink);text-decoration:underline;text-underline-offset:3px;text-decoration-color:var(--line)}
.site-foot a:hover{text-decoration-color:var(--ink)}
.site-foot p{margin:0}
body.legal{padding:0 16px}
.legal-top{max-width:760px;margin:0 auto;padding:22px 0 0}
.legal-home{font-weight:700;color:var(--ink);text-decoration:none}
.legal-home:hover{text-decoration:underline}
.legal-main{max-width:760px;margin:0 auto;padding:18px 0 0;line-height:1.65;font-size:16px}
.legal-main h1{font-family:var(--head);font-size:clamp(30px,6vw,44px);line-height:1.08;margin:6px 0 10px;text-wrap:balance}
.legal-main h2{font-family:var(--head);font-size:21px;margin:36px 0 8px;scroll-margin-top:20px}
.legal-kicker{color:var(--muted);font-size:13px;margin:0;font-weight:600;letter-spacing:.02em}
.legal-lede{color:var(--muted);font-size:18px;margin:0 0 18px}
.legal-main p,.legal-main li{max-width:68ch}
.legal-main ul{padding-left:22px}.legal-main li{margin:4px 0}
.legal-main a{color:var(--accent);text-underline-offset:2px}
.legal-toc{background:var(--wash);border:1px solid var(--line);border-radius:14px;padding:12px 18px}
.legal-toc ol{margin:0;padding-left:20px;columns:2;column-gap:28px;font-size:14px}
@media (max-width:560px){.legal-toc ol{columns:1}}
.legal-main .dt{width:100%;border-collapse:collapse;font-size:14px;margin:10px 0;display:block;overflow-x:auto}
.legal-main .dt th,.legal-main .dt td{border:1px solid var(--line);padding:8px 10px;text-align:left;vertical-align:top}
.legal-main .dt th{background:var(--wash)}
.legal-main code{font-family:var(--mono);font-size:13px;background:var(--wash);padding:1px 5px;border-radius:5px}
.legal-main .biz{display:grid;grid-template-columns:max-content 1fr;gap:6px 18px;margin:8px 0}
.legal-main .biz dt{font-weight:700}.legal-main .biz dd{margin:0}
@media (max-width:480px){.legal-main .biz{grid-template-columns:1fr}.legal-main .biz dd{margin-bottom:8px}}
.legal-main mark.todo{background:var(--warn-bg);color:var(--warn);font-weight:700;padding:0 4px;border-radius:4px}
.legal-foot{max-width:760px}