:root {
  --paper: #EEF2F5; --grid: #DAE2E9; --card: #FFFFFF; --ink: #13233A; --muted: #56677B; --rule: #C9D4DD;
  --line: #C8175D; --line-soft: #F7D3E1; --teal: #0E7C6B; --teal-soft: #D5EFEA; --amber: #A35F00; --amber-soft: #FBEBCF;
  --wrong: #B42318; --wrong-soft: #FBE1DE; --console: #15202C; --console-ink: #E3EAF1; --console-dim: #8FA3B8;
  --c1: #2F5D9E; --c2: #0E7C6B; --c3: #7A4BC2; --c4: #C8175D; --c5: #B35C00; --c6: #39708A;
  --display: "Bricolage Grotesque", "Avenir Next", system-ui, sans-serif;
  --body: "Atkinson Hyperlegible", system-ui, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, Menlo, monospace;
  --r-sm: 6px; --r-md: 12px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) {
  --paper: #0E161F; --grid: #1A2632; --card: #15202B; --ink: #E2EAF2; --muted: #95A6B8; --rule: #2A3947;
  --line: #FF5C93; --line-soft: #4A1A2E; --teal: #3CC8AE; --teal-soft: #11352F; --amber: #F2B04B; --amber-soft: #3A2A10;
  --wrong: #FF7B6E; --wrong-soft: #3D1A17; --console: #0A1118; --c1: #7FA8E8; --c2: #3CC8AE; --c3: #B392F0; --c4: #FF5C93; --c5: #F2A04B; --c6: #7DBAD6; color-scheme: dark; } }
:root[data-theme="dark"] {
  --paper: #0E161F; --grid: #1A2632; --card: #15202B; --ink: #E2EAF2; --muted: #95A6B8; --rule: #2A3947;
  --line: #FF5C93; --line-soft: #4A1A2E; --teal: #3CC8AE; --teal-soft: #11352F; --amber: #F2B04B; --amber-soft: #3A2A10;
  --wrong: #FF7B6E; --wrong-soft: #3D1A17; --console: #0A1118; --c1: #7FA8E8; --c2: #3CC8AE; --c3: #B392F0; --c4: #FF5C93; --c5: #F2A04B; --c6: #7DBAD6; color-scheme: dark; }

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 17px/1.6 var(--body);
  background-image: linear-gradient(var(--grid) 1px, transparent 1px), linear-gradient(90deg, var(--grid) 1px, transparent 1px); background-size: 28px 28px;
  display: grid; grid-template-columns: 230px minmax(0, 1fr); min-height: 100vh; }
a { color: var(--c1); text-underline-offset: 3px; }
:focus-visible { outline: 3px solid var(--line); outline-offset: 2px; border-radius: 4px; }
.skip { position: absolute; left: -999px; } .skip:focus { left: 8px; top: 8px; z-index: 10; background: var(--card); padding: 8px 12px; }
h1, h2, h3, h4, h5 { font-family: var(--display); line-height: 1.15; margin: 1.4em 0 .5em; letter-spacing: -0.01em; }
h1 { font-size: clamp(2rem, 4.5vw, 3rem); font-weight: 800; margin-top: .2em; outline: none; }
h1:focus, h1:focus-visible { outline: none; }
h2 { font-size: 1.6rem; font-weight: 700; } h3 { font-size: 1.25rem; font-weight: 700; } h4 { font-size: 1.05rem; margin: 0 0 .4em; } h5 { font-size: .95rem; margin: 0 0 .4em; color: var(--muted); }
p, li { max-width: 72ch; }
code { font-family: var(--mono); font-size: .86em; background: var(--grid); padding: 1px 5px; border-radius: 4px; }
.small { font-size: .86rem; color: var(--muted); }
.lede { font-size: 1.15rem; color: var(--muted); max-width: 62ch; }
.note { display: block; font-size: .85rem; color: var(--amber); margin-top: 4px; }

/* sidebar */
.side { position: sticky; top: 0; height: 100vh; padding: 22px 16px; background: var(--card); border-right: 1px solid var(--rule); display: flex; flex-direction: column; gap: 18px; }
.brand { display: flex; align-items: center; gap: 10px; font-family: var(--display); font-weight: 800; font-size: 1.15rem; color: var(--ink); text-decoration: none; }
.b-bg { fill: var(--ink); } .b-line { stroke: var(--line); stroke-width: 3; stroke-linecap: round; } .b-dot { fill: var(--paper); }
.nav { display: flex; flex-direction: column; gap: 2px; }
.nav a { color: var(--ink); text-decoration: none; padding: 8px 12px; border-radius: var(--r-sm); font-weight: 700; font-size: .98rem; border-left: 3px solid transparent; }
.nav a:hover { background: var(--paper); } .nav a.on { border-left-color: var(--line); background: var(--paper); }
.theme { margin-top: auto; display: flex; border: 1px solid var(--rule); border-radius: var(--r-sm); overflow: hidden; }
.theme button { flex: 1; background: none; border: 0; color: var(--muted); font: 700 .8rem var(--body); padding: 7px 4px; cursor: pointer; }
.theme button.on { background: var(--ink); color: var(--paper); }
.search input { width: 100%; font: inherit; font-size: .92rem; padding: 8px 10px; border: 1px solid var(--rule); border-radius: var(--r-sm); background: var(--paper); color: var(--ink); }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
main { min-width: 0; padding: 36px clamp(16px, 4vw, 56px) 80px; max-width: 980px; width: 100%; outline: none; }

/* buttons */
.btn { display: inline-flex; align-items: center; gap: 6px; background: var(--ink); color: var(--paper); border: 2px solid var(--ink); border-radius: var(--r-sm); padding: 9px 16px; font: 700 .95rem var(--body); cursor: pointer; text-decoration: none; }
.btn:hover { background: var(--line); border-color: var(--line); color: #fff; }
.btn.ghost { background: transparent; color: var(--ink); } .btn.ghost:hover { border-color: var(--line); color: var(--line); background: transparent; }
.btn.big { padding: 13px 22px; font-size: 1.02rem; }
.row { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; margin: 14px 0; }
.seg { display: inline-flex; border: 2px solid var(--ink); border-radius: var(--r-sm); overflow: hidden; }
.seg > * { padding: 7px 14px; background: transparent; border: 0; color: var(--ink); font: 700 .9rem var(--body); text-decoration: none; cursor: pointer; }
.seg > .on { background: var(--ink); color: var(--paper); }

/* hero */
.hero { display: grid; grid-template-columns: 1.1fr 1fr; gap: 28px; align-items: center; margin-bottom: 30px; }
.hero h1 { font-size: clamp(2.2rem, 5vw, 3.6rem); line-height: 1.02; margin-bottom: .3em; }
.hero-viz { position: relative; background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 10px; }
.hero-viz svg { width: 100%; display: block; }
.hero-eq { position: absolute; right: 18px; top: 14px; font: 600 1.05rem var(--mono); color: var(--line); background: var(--card); padding: 2px 8px; border-radius: 4px; }
#hero-svg .h-dot, #hero-svg .h-res { opacity: 0; } #hero-svg.shown .h-dot, #hero-svg.shown .h-res { animation: pop .35s ease-out forwards; animation-delay: calc(var(--d) * 35ms); }
@keyframes pop { from { opacity: 0; transform: translateY(-6px); } to { opacity: 1; transform: none; } }
@media (prefers-reduced-motion: reduce) { #hero-svg .h-dot, #hero-svg .h-res { opacity: 1; animation: none !important; } }

/* dashboard */
.dash { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin: 10px 0 24px; }
.tile { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 14px 16px; display: flex; flex-direction: column; gap: 4px; }
.t-k { font-size: .85rem; color: var(--muted); font-weight: 700; } .t-v { font: 800 2rem/1 var(--display); } .t-v small { font-size: 1rem; color: var(--muted); }
.meter { height: 6px; background: var(--grid); border-radius: 3px; overflow: hidden; margin-top: 6px; } .meter div { height: 100%; background: var(--line); }
.panel { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 6px 22px 18px; margin-bottom: 18px; }
.panel h2 { margin-top: .8em; }
.plan li { margin: 6px 0; } .next { margin-top: 14px; }
.mchart { display: grid; gap: 7px; } .mrow { display: grid; grid-template-columns: 190px 1fr 92px; gap: 10px; align-items: center; font-size: .92rem; }
.mtrack { height: 14px; background: var(--grid); border-radius: 3px; overflow: hidden; } .mfill { height: 100%; } .mfill.hi { background: var(--teal); } .mfill.md { background: var(--amber); } .mfill.lo { background: var(--wrong); }
.mv { font-weight: 700; } .mv small { color: var(--muted); font-weight: 400; }

/* lessons */
.lesson-list { display: grid; gap: 12px; }
.lesson-card { display: grid; grid-template-columns: 54px 1fr; gap: 14px; background: var(--card); border: 1px solid var(--rule); border-left: 6px solid var(--lc); border-radius: var(--r-md); padding: 16px; color: var(--ink); text-decoration: none; }
.lesson-card:hover { border-color: var(--lc); }
.lesson-card h3 { margin: 0 0 4px; } .lesson-card p { margin: 0 0 6px; color: var(--muted); }
.ln { font: 800 2.2rem/1 var(--display); color: var(--lc); }
.crumb { font-size: .9rem; color: var(--muted); margin-bottom: 8px; }
.lesson h1 { border-bottom: 6px solid var(--lc); padding-bottom: 8px; display: inline-block; }
.hook { font-size: 1.25rem; font-family: var(--display); font-weight: 500; color: var(--muted); }
.lesson h3 { color: var(--lc); }
.big-steps li { font-size: 1.1rem; margin: 6px 0; }
.chips { list-style: none; padding: 0; display: flex; flex-wrap: wrap; gap: 8px; } .chips li { background: var(--card); border: 1px solid var(--rule); border-radius: 30px; padding: 6px 14px; }
.two { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin: 14px 0; } .three { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin: 14px 0; }
.callout { background: var(--card); border: 1px solid var(--rule); border-top: 4px solid var(--c1); border-radius: var(--r-sm); padding: 14px 16px; }
.callout p, .callout ul { margin: .3em 0; font-size: .96rem; } .callout ul { padding-left: 18px; }
.callout.ok { border-top-color: var(--teal); } .callout.bad { border-top-color: var(--wrong); }
.eq { font: 600 1.05rem var(--mono); background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-sm); padding: 12px 16px; margin: 12px 0; overflow-x: auto; }
.eq.big { font-size: 1.4rem; text-align: center; }
.anatomy { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; align-items: center; }
.tag { padding: 1px 6px; border-radius: 4px; } .t0 { background: var(--teal-soft); color: var(--teal); } .t1 { background: var(--line-soft); color: var(--line); }
.anat-key p { margin: 6px 0; }
.check { margin-top: 40px; padding-top: 10px; border-top: 2px dashed var(--rule); }
.explain-back { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 4px 18px 18px; margin-top: 18px; }
.pager { display: flex; justify-content: space-between; gap: 12px; margin-top: 30px; font-weight: 700; }
.steps { padding-left: 1.3em; } .steps li { margin: 6px 0; }
.takeaway { background: var(--amber-soft); border-left: 4px solid var(--amber); padding: 8px 12px; border-radius: 4px; font-weight: 700; }

/* tables */
.tbl { border-collapse: collapse; width: 100%; background: var(--card); font-size: .93rem; margin: 12px 0; }
.tbl th, .tbl td { border: 1px solid var(--rule); padding: 7px 10px; text-align: left; vertical-align: top; }
.tbl th { background: var(--grid); font-family: var(--display); }
.grid-tbl td { font-weight: 700; }
.tblwrap { overflow-x: auto; }

/* R output */
.rout, .code { background: var(--console); color: var(--console-ink); font: .82rem/1.55 var(--mono); padding: 14px 16px; border-radius: var(--r-sm); overflow-x: auto; white-space: pre; }
.code { color: #BFE6D8; }

/* widgets */
.widget { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 16px 18px; margin: 18px 0; }
.w-title { font: 700 1.05rem var(--display); margin-bottom: 10px; display: flex; align-items: center; gap: 8px; }
.w-title::before { content: ""; width: 18px; height: 3px; background: var(--line); border-radius: 2px; }
.w-read { margin: 8px 0 0; }
.svgwrap { width: 100%; } .chart { width: 100%; height: auto; display: block; touch-action: manipulation; }
.chart .gl, .mini .gl, #hero-svg .gl { stroke: var(--grid); stroke-width: 1; }
.axis { stroke: var(--muted); stroke-width: 1.5; }
.dot { fill: var(--c1); } .dot.soft { fill: var(--c1); opacity: .55; } .dot.hot { fill: var(--line); stroke: var(--card); stroke-width: 2; }
.dot.flag { stroke: var(--amber); stroke-width: 3; }
.dot.c0 { fill: var(--c1); } .dot.c1 { fill: var(--teal); } .dot.c2 { fill: var(--c3); }
.fit { stroke: var(--line); stroke-width: 3.5; stroke-linecap: round; fill: none; }
.ghostline { stroke: var(--muted); stroke-width: 2; stroke-dasharray: 6 5; fill: none; }
.resid { stroke: var(--line); stroke-width: 1.2; opacity: .45; }
.half { stroke: var(--muted); stroke-dasharray: 4 4; stroke-width: 1.4; }
.guide { stroke: var(--line); stroke-dasharray: 3 3; stroke-width: 1.4; }
.tick { fill: var(--muted); font: 12px var(--body); } .lbl { fill: var(--ink); font: 700 13px var(--body); }
.m-line { stroke: var(--line); fill: var(--line); stroke-width: 2.5; } .md-line { stroke: var(--teal); fill: var(--teal); stroke-width: 2.5; }
text.m-line, text.md-line { stroke: none; }
.ci { stroke: var(--muted); stroke-width: 3; } .ci.sig { stroke: var(--teal); } .pt { fill: var(--muted); } .pt.sig { fill: var(--teal); }
.ctrls { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 10px 18px; }
.sl { display: flex; flex-direction: column; font-size: .9rem; font-weight: 700; }
.sl span { display: flex; justify-content: space-between; } .sl output { font-family: var(--mono); color: var(--line); }
input[type=range] { accent-color: var(--line); width: 100%; }
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 8px; margin-top: 10px; }
.stat { background: var(--paper); border-radius: var(--r-sm); padding: 8px 10px; font-size: .93rem; } .stat span { display: block; font-size: .78rem; color: var(--muted); font-weight: 700; }
.stat.wide { grid-column: 1 / -1; }
.tog { font-size: .9rem; display: flex; gap: 6px; align-items: center; }
.num { display: flex; flex-direction: column; font-weight: 700; font-size: .9rem; } .num input { font: inherit; padding: 6px 8px; border: 1px solid var(--rule); border-radius: var(--r-sm); background: var(--paper); color: var(--ink); width: 160px; }
.q { font-size: 1.08rem; font-weight: 700; }
.opts { display: flex; flex-direction: column; gap: 8px; } .opts.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr)); }
.opt { text-align: left; background: var(--paper); border: 2px solid var(--rule); border-radius: var(--r-sm); padding: 10px 14px; font: inherit; color: var(--ink); cursor: pointer; }
.opt:hover:not(:disabled) { border-color: var(--ink); } .opt.right { border-color: var(--teal); background: var(--teal-soft); } .opt.wrong { border-color: var(--wrong); background: var(--wrong-soft); }
.crumbs { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 8px; } .crumbs span { font-size: .8rem; background: var(--paper); border-radius: 20px; padding: 2px 10px; color: var(--muted); }
.result { text-align: center; padding: 14px; } .result .answer { font: 800 2rem var(--display); color: var(--line); margin: 4px 0 12px; }
.good { color: var(--teal); font-weight: 700; } .badtxt { color: var(--wrong); font-weight: 700; }
.pipeline { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; margin: 16px 0; counter-reset: s; }
.pstep { background: var(--card); border: 1px solid var(--rule); padding: 14px; position: relative; }
.pstep:not(:last-child)::after { content: ""; position: absolute; right: -11px; top: 26px; width: 20px; height: 20px; background: var(--card); border-top: 1px solid var(--rule); border-right: 1px solid var(--rule); transform: rotate(45deg); z-index: 1; }
.pstep:first-child { border-radius: var(--r-md) 0 0 var(--r-md); } .pstep:last-child { border-radius: 0 var(--r-md) var(--r-md) 0; }
.pnum { font: 800 1.8rem/1 var(--display); color: var(--line); } .pstep h4 { margin: 6px 0; } .pstep p { font-size: .88rem; margin: 0; color: var(--muted); }
.assume-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 12px; margin: 14px 0; }
.acard { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 14px; display: flex; flex-direction: column; }
.aletter { font: 800 2rem/1 var(--display); color: var(--c4); } .acard h4 { margin: 4px 0 8px; }
.aviz p { font-size: .86rem; margin: 6px 0 10px; min-height: 3em; }
.acard[data-state=pass] .fail, .acard[data-state=fail] .pass { display: none; }
.acard[data-state=fail] .aviz p { color: var(--wrong); } .acard[data-state=pass] .aviz p { color: var(--teal); }
.acard .seg { margin-top: auto; align-self: flex-start; } .acard .seg > * { padding: 4px 10px; font-size: .82rem; }
.mini { width: 100%; height: auto; background: var(--paper); border-radius: var(--r-sm); }
.mini .bar { fill: var(--c1); } .mini .bar.bad { fill: var(--line); } .mini .dot { fill: var(--c1); } .mini .clus { fill: var(--line-soft); stroke: var(--line); }
.decoder .hot { background: rgba(255, 92, 147, .18); border-bottom: 2px solid var(--line); cursor: pointer; border-radius: 2px; }
.decoder .hot.on { background: var(--line); color: #fff; }
.dec-out { background: var(--paper); border-left: 4px solid var(--line); padding: 10px 14px; border-radius: 4px; min-height: 3.2em; }
.form { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 10px 14px; }
.form label { display: flex; flex-direction: column; font-size: .85rem; font-weight: 700; color: var(--muted); }
.form input, .form select { font: inherit; font-size: .95rem; color: var(--ink); padding: 7px 9px; border: 1px solid var(--rule); border-radius: var(--r-sm); background: var(--paper); margin-top: 3px; }
.form input:disabled { opacity: .45; }
.sentence { margin-top: 14px; background: var(--paper); border-left: 4px solid var(--teal); padding: 6px 14px; border-radius: 4px; font-size: 1.05rem; }
.ladder { display: grid; gap: 12px; margin-top: 12px; } .lrow { display: grid; grid-template-columns: 170px 1fr 170px; gap: 12px; align-items: center; }
.lk { font-weight: 700; font-size: .92rem; } .lk small { color: var(--muted); font-weight: 400; }
.lbar { height: 22px; background: var(--paper); border-radius: 4px; position: relative; overflow: hidden; } .lbar > div { height: 100%; position: absolute; left: 0; top: 0; }
.lbar.center::before { content: ""; position: absolute; left: 50%; top: 0; bottom: 0; width: 2px; background: var(--muted); }
.lb1 { background: var(--c1); } .lb2 { background: var(--c5); } .lb3 { background: var(--line); }
.lv { font: .88rem var(--mono); }
.fwbar { height: 18px; background: var(--paper); border-radius: 4px; overflow: hidden; margin-top: 10px; } .fwbar div { height: 100%; background: var(--wrong); transition: width .3s; }
.tbl.edit input { width: 64px; font: .9rem var(--mono); padding: 3px 5px; border: 1px solid var(--rule); border-radius: 4px; background: var(--paper); color: var(--ink); }
.tbl.edit td, .tbl.edit th { padding: 4px 6px; } .x { background: none; border: 0; color: var(--wrong); font-size: 1.2rem; cursor: pointer; }

/* questions */
.q-card { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 16px 18px; margin: 14px 0; }
.q-card header { display: grid; grid-template-columns: auto 1fr auto; gap: 12px; align-items: start; }
.qnum { font: 800 1rem var(--display); background: var(--ink); color: var(--paper); border-radius: var(--r-sm); min-width: 34px; height: 34px; display: grid; place-items: center; padding: 0 6px; }
.prompt { font-size: 1.04rem; padding-top: 4px; }
.badge { font-size: .74rem; font-weight: 700; padding: 3px 9px; border-radius: 20px; white-space: nowrap; }
.badge.ok { background: var(--teal-soft); color: var(--teal); } .badge.mid { background: var(--amber-soft); color: var(--amber); } .badge.no { background: var(--wrong-soft); color: var(--wrong); }
.src { font-size: .8rem; color: var(--muted); margin-bottom: 8px; font-weight: 700; }
.choices { display: flex; flex-direction: column; gap: 8px; margin: 14px 0 4px; }
.choice { display: flex; gap: 12px; align-items: flex-start; text-align: left; background: var(--paper); border: 2px solid transparent; border-radius: var(--r-sm); padding: 10px 12px; font: inherit; color: var(--ink); cursor: pointer; }
.choice:hover:not(:disabled) { border-color: var(--rule); } .choice.sel { border-color: var(--ink); }
.choice.right { border-color: var(--teal); background: var(--teal-soft); } .choice.wrong { border-color: var(--wrong); background: var(--wrong-soft); }
.choice:disabled { cursor: default; }
.letter { font: 700 .9rem var(--mono); background: var(--card); border: 1px solid var(--rule); border-radius: 4px; width: 24px; height: 24px; display: grid; place-items: center; flex: none; }
.choices.pills { flex-direction: row; flex-wrap: wrap; } .choice.pill { padding: 6px 12px; border-radius: 30px; font-size: .92rem; }
.chk input { margin-top: 5px; accent-color: var(--line); }
.blank-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 14px 0 4px; }
.blank { font: inherit; padding: 9px 12px; border: 2px solid var(--rule); border-radius: var(--r-sm); background: var(--paper); color: var(--ink); flex: 1; min-width: 160px; }
.essay { width: 100%; font: inherit; padding: 12px; border: 2px solid var(--rule); border-radius: var(--r-sm); background: var(--paper); color: var(--ink); margin-top: 12px; resize: vertical; }
.explain-back textarea { width: 100%; font: inherit; padding: 12px; border: 2px solid var(--rule); border-radius: var(--r-sm); background: var(--paper); color: var(--ink); }
.conf { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; margin-top: 10px; }
.conf button { background: none; border: 1px solid var(--rule); border-radius: 20px; padding: 3px 11px; font: inherit; font-size: .82rem; color: var(--muted); cursor: pointer; }
.conf button.on { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.feedback { margin-top: 14px; border-top: 1px solid var(--rule); padding-top: 12px; }
.verdict { font: 800 1.1rem var(--display); margin: 0 0 6px; } .is-ok .verdict { color: var(--teal); } .is-no .verdict { color: var(--wrong); }
.explain, .model, .rubric { background: var(--paper); border-radius: var(--r-sm); padding: 12px 16px; margin: 10px 0; }
.model { border-left: 4px solid var(--teal); } .rubric label { display: flex; gap: 8px; margin: 4px 0; font-size: .95rem; } .rubric input { accent-color: var(--teal); }
.q-card.answered { border-color: var(--ink); }

/* exams */
.exam-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 14px; }
.exam-card { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 18px; display: flex; flex-direction: column; }
.exam-card h3 { margin: 0 0 6px; } .exam-card p { color: var(--muted); margin: 0 0 12px; flex: 1; }
.modebar { position: sticky; top: 0; z-index: 3; background: var(--paper); padding: 10px 0; display: flex; flex-wrap: wrap; gap: 12px; align-items: center; border-bottom: 1px solid var(--rule); }
.timer { font: 700 1.1rem var(--mono); color: var(--line); }
.toc { display: flex; flex-wrap: wrap; gap: 4px 12px; font-size: .88rem; font-weight: 700; }
.exam-sec h2 { margin-top: 1.4em; padding-top: 8px; }
.submitbar { position: sticky; bottom: 0; background: var(--paper); border-top: 1px solid var(--rule); padding: 14px 0; z-index: 3; }
.scorecard { display: flex; gap: 16px; align-items: center; }

/* flashcards */
.boxes { display: flex; gap: 10px; align-items: flex-end; margin: 10px 0 24px; flex-wrap: wrap; }
.box { display: flex; flex-direction: column; align-items: center; font-size: .8rem; min-width: 56px; } .box span { color: var(--muted); font-weight: 700; } .box small { color: var(--muted); }
.bx { width: 44px; background: var(--c1); border-radius: 4px 4px 0 0; }
.flash { display: block; width: 100%; max-width: 640px; min-height: 240px; perspective: 1000px; background: var(--card); border: 2px solid var(--ink); border-radius: var(--r-md); padding: 34px 28px; font: inherit; color: var(--ink); cursor: pointer; position: relative; text-align: center; box-shadow: 6px 6px 0 var(--line); margin: 8px 0; }
.flash .front { font: 800 1.6rem/1.2 var(--display); } .flash .back { display: none; font-size: 1.15rem; }
.flash.flipped .front { font-size: 1rem; color: var(--muted); margin-bottom: 14px; } .flash.flipped .back { display: block; }
.flash .hint { position: absolute; bottom: 8px; left: 0; right: 0; font-size: .78rem; color: var(--muted); }
.done { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 18px; }

/* labs */
.lab-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 12px; }
.lab-card { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 16px; color: var(--ink); text-decoration: none; border-bottom: 4px solid var(--line); }
.lab-card:hover { border-color: var(--line); } .lab-card h3 { margin: 0 0 6px; } .lab-card p { margin: 0; color: var(--muted); font-size: .94rem; }

/* sheet */
.sheet { display: grid; grid-template-columns: repeat(auto-fill, minmax(270px, 1fr)); gap: 12px; }
.sheet > div { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-sm); padding: 4px 14px 10px; }
.sheet h3 { margin: .6em 0 .3em; font-size: 1.05rem; color: var(--line); } .sheet p { font-size: .9rem; margin: 0; }

/* responsive */
/* start here */
.wwh { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; } .wwh h3 { margin-top: .4em; }
.why { padding-left: 1.1em; } .why li { margin: 5px 0; }
.family { margin: 10px 0 6px; } .fam-root { background: var(--ink); color: var(--paper); border-radius: var(--r-md); padding: 12px 18px; display: flex; flex-wrap: wrap; gap: 4px 12px; align-items: baseline; justify-content: center; text-align: center; position: relative; }
.fam-root b { font: 800 1.1rem var(--display); } .fam-root span { opacity: .8; }
.fam-kids { display: grid; grid-template-columns: repeat(5, 1fr); gap: 10px; margin-top: 22px; position: relative; }
.fam-kids::before { content: ""; position: absolute; left: 10%; right: 10%; top: -12px; border-top: 2px solid var(--rule); }
.fam { position: relative; display: flex; flex-direction: column; gap: 4px; background: var(--paper); border: 1px solid var(--rule); border-top: 5px solid var(--fc); border-radius: var(--r-sm); padding: 10px 12px; color: var(--ink); text-decoration: none; font-size: .88rem; }
.fam::before { content: ""; position: absolute; top: -18px; left: 50%; height: 13px; border-left: 2px solid var(--rule); }
.fam b { font: 700 1rem var(--display); } .fk { font-size: .78rem; font-weight: 700; color: var(--fc); } .fam:hover { border-color: var(--fc); }
.approach { list-style: none; padding: 0; display: grid; grid-template-columns: repeat(5, 1fr); gap: 0; counter-reset: ap; }
.approach li { counter-increment: ap; background: var(--paper); border: 1px solid var(--rule); padding: 12px; display: flex; flex-direction: column; gap: 4px; font-size: .88rem; position: relative; }
.approach li::before { content: counter(ap); font: 800 1.6rem/1 var(--display); color: var(--line); }
.approach li b { font: 700 1.02rem var(--display); }
.approach li:first-child { border-radius: var(--r-md) 0 0 var(--r-md); } .approach li:last-child { border-radius: 0 var(--r-md) var(--r-md) 0; }
.cmap { list-style: none; padding: 0; margin: 8px 0; display: grid; gap: 0; }
.cmap li { display: grid; grid-template-columns: 70px 1fr auto; gap: 12px; align-items: center; padding: 8px 10px; border-left: 3px solid var(--rule); font-size: .94rem; }
.cmap li.past { color: var(--muted); } .cmap li.now { border-left-color: var(--line); background: var(--line-soft); border-radius: 0 var(--r-sm) var(--r-sm) 0; font-weight: 700; }
.cd { font: 700 .86rem var(--mono); font-variant-numeric: tabular-nums; } .cl { display: flex; flex-wrap: wrap; gap: 4px 10px; font-size: .86rem; justify-content: flex-end; }
.pathbox { margin-top: 12px; } .checklist { list-style: none; padding: 0; display: grid; gap: 6px; }
.checklist li { display: flex; justify-content: space-between; gap: 12px; align-items: center; background: var(--paper); border-radius: var(--r-sm); padding: 8px 12px; }
.checklist label { display: flex; gap: 10px; align-items: flex-start; cursor: pointer; } .checklist input { margin-top: 5px; accent-color: var(--teal); }
.checklist input:checked + span { text-decoration: line-through; color: var(--muted); }
.seg button[aria-selected] { white-space: nowrap; }
.integrity { margin-top: 18px; }
/* guides */
.guide-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 12px; }
.guide-card { background: var(--card); border: 1px solid var(--rule); border-left: 5px solid var(--teal); border-radius: var(--r-md); padding: 14px 16px; color: var(--ink); text-decoration: none; }
.guide-card:hover { border-color: var(--teal); } .guide-card h3 { margin: 0 0 6px; font-size: 1.08rem; } .guide-card p { margin: 0 0 6px; color: var(--muted); font-size: .92rem; }
.gvis { margin: 16px 0; }
.flow { display: flex; flex-wrap: wrap; gap: 0; }
.fl { flex: 1 1 140px; background: var(--card); border: 1px solid var(--rule); padding: 12px 18px 12px 22px; position: relative; display: flex; flex-direction: column; font-size: .88rem; }
.fl b { font: 700 1rem var(--display); color: var(--teal); } .fl span { color: var(--muted); }
.fl:not(:last-child)::after { content: ""; position: absolute; right: -9px; top: 50%; width: 16px; height: 16px; margin-top: -8px; background: var(--card); border-top: 1px solid var(--rule); border-right: 1px solid var(--rule); transform: rotate(45deg); z-index: 1; }
.gsteps { list-style: none; padding: 0; display: grid; gap: 10px; }
.gsteps li { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 12px 16px; }
.gsteps li.done { border-color: var(--teal); background: var(--teal-soft); }
.gs-head { display: grid; grid-template-columns: auto 1fr auto; gap: 12px; align-items: center; }
.gs-head h3 { margin: 0; font-size: 1.05rem; color: var(--ink) !important; }
.gs-n { font: 800 1rem var(--display); background: var(--teal); color: var(--card); width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center; }
.gs-chk { font-size: .85rem; color: var(--muted); display: flex; gap: 6px; align-items: center; } .gs-chk input { accent-color: var(--teal); }
.gsteps p { margin: 8px 0 4px; }
.codewrap { position: relative; } .codewrap .code { margin: 8px 0 0; padding-right: 70px; }
.copy { position: absolute; top: 6px; right: 6px; font: 700 .75rem var(--body); background: var(--card); color: var(--ink); border: 1px solid var(--rule); border-radius: 4px; padding: 3px 8px; cursor: pointer; }
.mistakes li { margin: 4px 0; } .mistakes li::marker { color: var(--wrong); }
/* templates */
.tpl { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 14px 18px; margin: 12px 0; }
.tpl header { display: flex; justify-content: space-between; gap: 10px; align-items: center; } .tpl h3 { margin: 0; font-size: 1.08rem; }
.cue { margin: 8px 0; font-size: .92rem; color: var(--muted); } .cue span { display: inline-block; font-weight: 700; color: var(--c1); margin-right: 8px; }
.ttext { position: relative; font-size: 1.04rem; line-height: 1.75; background: var(--paper); border-left: 4px solid var(--line); border-radius: 4px; padding: 12px 70px 12px 14px; }
.tok { background: var(--line-soft); color: var(--line); font-weight: 700; padding: 1px 6px; border-radius: 4px; white-space: normal; }
.tex { margin: 10px 0 4px; } .tex p { margin: 2px 0; font-style: italic; }
.ttips { margin: 6px 0 0; padding-left: 1.2em; font-size: .9rem; color: var(--muted); }
.tpl textarea { width: 100%; font: inherit; padding: 10px; border: 2px solid var(--rule); border-radius: var(--r-sm); background: var(--paper); color: var(--ink); margin-bottom: 8px; }
.tpl.compact { margin: 10px 0; }
.tpl-bar { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 10px; align-items: center; margin-top: 18px; }
.chips-row { display: flex; flex-wrap: wrap; gap: 6px; margin: 8px 0; }
.chip { background: var(--card); border: 1px solid var(--rule); color: var(--ink); border-radius: 30px; padding: 5px 12px; font: 700 .86rem var(--body); text-decoration: none; cursor: pointer; }
.chip.on { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.finder h2 { margin-top: .6em; } .fd-out { margin-top: 6px; }
/* definitions */
.def-bar { display: flex; flex-wrap: wrap; gap: 10px; margin: 6px 0; } .def-bar input { flex: 1; min-width: 200px; font: inherit; padding: 9px 12px; border: 2px solid var(--rule); border-radius: var(--r-sm); background: var(--card); color: var(--ink); }
.dlist { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 10px; margin: 0; }
.dterm { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-sm); padding: 10px 14px; }
.dterm dt { font: 700 1.02rem var(--display); margin-bottom: 4px; } .dterm dd { margin: 0; font-size: .94rem; }
.dex { display: block; margin-top: 6px; font-size: .88rem; color: var(--muted); font-style: italic; } .drel { display: block; margin-top: 6px; font-size: .84rem; }
.hl { outline: 3px solid var(--line); outline-offset: 2px; }
/* search */
.results { list-style: none; padding: 0; display: grid; gap: 8px; } .results li { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-sm); padding: 10px 14px; }
.results a { font-weight: 700; } .results p { margin: 4px 0 0; font-size: .9rem; color: var(--muted); }
mark { background: var(--amber-soft); color: var(--ink); padding: 0 2px; border-radius: 2px; }
.deeper { font-size: .9rem; margin: 10px 0 0; }
.deckseg { flex-wrap: wrap; margin-bottom: 14px; } .deckseg small { opacity: .75; font-weight: 400; }
.flash.tplcard .front { font-size: 1.15rem; } .flash.tplcard .back { text-align: left; line-height: 1.75; }

@media (max-width: 900px) {
  body { grid-template-columns: minmax(0, 1fr); }
  .side { position: sticky; top: 0; z-index: 5; height: auto; flex-direction: row; align-items: center; padding: 10px 16px; gap: 12px; overflow-x: auto; }
  .brand span { display: none; }
  .nav { flex-direction: row; gap: 2px; } .nav a { white-space: nowrap; padding: 6px 10px; border-left: 0; border-bottom: 3px solid transparent; font-size: .9rem; } .nav a.on { border-bottom-color: var(--line); }
  .theme { margin: 0; flex: none; } .search { flex: none; width: 150px; }
  .modebar { top: 58px; }
  .hero { grid-template-columns: 1fr; } .dash { grid-template-columns: 1fr 1fr; }
  .two, .three, .anatomy, .wwh { grid-template-columns: 1fr; }
  .fam-kids { grid-template-columns: 1fr 1fr; } .fam-kids::before, .fam::before { display: none; }
  .approach { grid-template-columns: 1fr; } .approach li { border-radius: var(--r-sm) !important; margin-bottom: 4px; }
  .cmap li { grid-template-columns: 56px 1fr; } .cl { grid-column: 2; justify-content: flex-start; }
  .flow { flex-direction: column; } .fl:not(:last-child)::after { display: none; }
  .pipeline { grid-template-columns: 1fr 1fr; gap: 8px; } .pstep { border-radius: var(--r-md) !important; } .pstep::after { display: none; }
  .mrow { grid-template-columns: 120px 1fr 70px; font-size: .84rem; }
  .lrow { grid-template-columns: 1fr; gap: 4px; }
  .tbl { display: block; overflow-x: auto; }
}
@media (max-width: 520px) { main { padding: 22px 16px 70px; } .dash { grid-template-columns: 1fr 1fr; } .t-v { font-size: 1.6rem; } .pipeline { grid-template-columns: 1fr; } .tbl { font-size: .85rem; } }
@media print { .side, .modebar, .btn, .theme { display: none !important; } body { display: block; background: #fff; } .sheet > div { break-inside: avoid; } }
.seg { flex-wrap: wrap; max-width: 100%; }
.gsteps li, .gsteps, .tpl, .q-card, .widget, .panel, .callout { min-width: 0; }
.gsteps li .code, .tpl .ttext { max-width: 100%; }

/* ---------- Start from zero ---------- */
.zlist { list-style: none; padding: 0; display: grid; gap: 8px; }
.zlist a { display: grid; grid-template-columns: 44px 1fr; gap: 12px; align-items: center; background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 12px 16px; color: var(--ink); text-decoration: none; }
.zlist a:hover { border-color: var(--teal); }
.zlist a > span:last-child { display: flex; flex-direction: column; gap: 2px; } .zlist a > span:last-child > span { color: var(--muted); font-size: .94rem; }
.zn { font: 800 1.3rem/1 var(--display); width: 40px; height: 40px; border-radius: 50%; display: grid; place-items: center; background: var(--paper); color: var(--teal); border: 2px solid var(--teal); }
.zlist li.done .zn { background: var(--teal); color: var(--card); }
.zbar { display: flex; gap: 4px; margin: 6px 0 18px; } .zbar a { flex: 1; height: 8px; border-radius: 4px; background: var(--grid); }
.zbar a.done { background: var(--teal); } .zbar a.on { background: var(--line); }
.bigidea { font: 500 1.3rem/1.45 var(--display); background: var(--teal-soft); border-radius: var(--r-md); padding: 14px 18px; margin: 0 0 18px; max-width: none; }
.bigidea span { display: block; font: 700 .85rem var(--body); color: var(--teal); margin-bottom: 2px; }
.zgrid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr); gap: 24px; align-items: start; }
.zstory { font-size: 1.08rem; line-height: 1.7; } .zstory p, .zstory li { max-width: 60ch; }
.zfig { margin: 0; background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 12px; position: sticky; top: 12px; }
.rule { background: var(--amber-soft); border-left: 4px solid var(--amber); padding: 8px 12px; border-radius: 4px; }
.cap { font-size: .88rem; color: var(--muted); margin: 4px 0 0; text-align: center; }
.icons-row { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin-top: 10px; }
.ic { background: var(--i); color: var(--card); font-weight: 700; padding: 6px 12px; border-radius: 20px; font-size: .9rem; }
.three-charts { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; } .two-charts { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.chart .ring { fill: none; stroke: var(--line); stroke-width: 2.5; }
.chart .t0txt { fill: var(--teal); } .chart .t1txt { fill: var(--line); }
.chart .step { fill: none; stroke: var(--line); stroke-width: 2.5; stroke-dasharray: 5 4; }
.chart .resid.thick { stroke-width: 2.5; opacity: .75; }
.chart .bar { fill: var(--c1); } .chart .bar.alt { fill: var(--teal); } .chart .bar.hotbar { fill: var(--line); }
.chart .dot.sun { fill: var(--c5); } .chart .meanbar { stroke: var(--ink); stroke-width: 4; stroke-linecap: round; }
.chart .pyes { fill: var(--teal); } .chart .pno { fill: var(--grid); stroke: var(--muted); stroke-width: 1.5; }
.chart .orbox { fill: var(--amber-soft); stroke: var(--amber); } .chart .lbl.big { font-size: 17px; }
.pick-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 12px; }
.pk { background: var(--card); border: 1px solid var(--rule); border-top: 4px solid var(--teal); border-radius: var(--r-sm); padding: 10px 12px; display: flex; flex-direction: column; gap: 4px; font-size: .95rem; }
.zwords, .zcheck { background: var(--card); border: 1px solid var(--rule); border-radius: var(--r-md); padding: 4px 18px 16px; margin-top: 18px; }
.zwords h2, .zcheck h2 { font-size: 1.2rem; margin-top: .8em; }
.xlate td:last-child { color: var(--ink); } .xlate td:first-child { color: var(--muted); }
.zcheck .fb .btn { margin-top: 6px; }
.plainbox { background: var(--teal-soft); border-left: 5px solid var(--teal); border-radius: var(--r-sm); padding: 12px 16px; margin: 6px 0 18px; font-size: 1.05rem; }
.plainbox span { display: block; margin-top: 6px; font-size: .92rem; }
@media (max-width: 900px) { .zgrid { grid-template-columns: minmax(0, 1fr); } .zfig { position: static; } .three-charts { grid-template-columns: 1fr; } .two-charts, .pick-grid { grid-template-columns: 1fr; } }