/* ============ Tokens ============ */
:root{
  --bg:#f5f6f3; --panel:#ffffff; --ink:#1c2830; --muted:#5d6a70; --line:#d9ddd6; --grid:#eceee9;
  --accent:#1f6f5c; --accent-ink:#ffffff; --accent-soft:#e3efe9; --chip:#e7ece6;
  /* chart series */
  --c-d:#2166ac; --c-s:#c1561d; --c-lr:#3b4a52; --c-alt:#7b3fa6; --c-pt:#d9a21b;
  --c-up:#1a8a4a; --c-down:#b8323c;
  --f-cs:rgba(33,102,172,.16); --f-ps:rgba(193,86,29,.16); --f-dwl:rgba(184,50,60,.22);
  --f-gov:rgba(123,63,166,.18); --f-tr:rgba(217,162,27,.28); --f-gain:rgba(26,138,74,.26); --f-loss:rgba(184,50,60,.24);
  --serif:"Source Serif 4", Georgia, "Times New Roman", serif;
  --sans:"IBM Plex Sans", "Helvetica Neue", Arial, sans-serif;
  --mono:"IBM Plex Mono", ui-monospace, Menlo, monospace;
  --radius:12px;
  color-scheme:light;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    color-scheme:dark;
    --bg:#141a1d; --panel:#1b2327; --ink:#e3e8e6; --muted:#9aa7ab; --line:#2f3a3f; --grid:#232d31;
    --accent:#4fb393; --accent-ink:#0d1b16; --accent-soft:#1f3a31; --chip:#253033;
    --c-d:#6fa8dc; --c-s:#ec8c55; --c-lr:#b3c0c5; --c-alt:#b98ae0; --c-pt:#f0c04a;
    --c-up:#58c486; --c-down:#ef7680;
    --f-cs:rgba(111,168,220,.20); --f-ps:rgba(236,140,85,.20); --f-dwl:rgba(239,118,128,.28);
    --f-gov:rgba(185,138,224,.24); --f-tr:rgba(240,192,74,.26); --f-gain:rgba(88,196,134,.28); --f-loss:rgba(239,118,128,.28);
  }
}
:root[data-theme="dark"]{
  color-scheme:dark;
  --bg:#141a1d; --panel:#1b2327; --ink:#e3e8e6; --muted:#9aa7ab; --line:#2f3a3f; --grid:#232d31;
  --accent:#4fb393; --accent-ink:#0d1b16; --accent-soft:#1f3a31; --chip:#253033;
  --c-d:#6fa8dc; --c-s:#ec8c55; --c-lr:#b3c0c5; --c-alt:#b98ae0; --c-pt:#f0c04a;
  --c-up:#58c486; --c-down:#ef7680;
  --f-cs:rgba(111,168,220,.20); --f-ps:rgba(236,140,85,.20); --f-dwl:rgba(239,118,128,.28);
  --f-gov:rgba(185,138,224,.24); --f-tr:rgba(240,192,74,.26); --f-gain:rgba(88,196,134,.28); --f-loss:rgba(239,118,128,.28);
}

/* ============ Base ============ */
*{box-sizing:border-box}
[hidden]{display:none!important}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--sans);font-size:16px;line-height:1.55;-webkit-font-smoothing:antialiased}
img{max-width:100%;display:block}
a{color:var(--accent)}
h1,h2,h3{font-family:var(--serif);font-weight:650;letter-spacing:-.01em;line-height:1.15;text-wrap:balance;margin:0}
p{margin:0}
.wrap{max-width:1120px;margin:0 auto;padding-inline:16px}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}

/* ============ Nav ============ */
.site-head{position:sticky;top:0;z-index:20;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:12px;min-height:60px;flex-wrap:wrap}
.brand{font-family:var(--serif);font-weight:650;font-size:19px;color:var(--ink);text-decoration:none;display:flex;align-items:baseline;gap:8px}
.brand small{font-family:var(--sans);font-weight:500;font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.nav{display:flex;gap:4px;flex-wrap:wrap}
.nav a{color:var(--ink);text-decoration:none;font-size:15px;padding:7px 12px;border-radius:999px}
.nav a:hover{background:var(--chip)}
.nav a[aria-current="page"]{background:var(--ink);color:var(--bg)}
@media (max-width:560px){.brand small{display:none}.nav a{padding:6px 9px;font-size:14px}}

/* ============ Common blocks ============ */
main{padding-block:32px 56px}
.eyebrow{font-size:12px;letter-spacing:.1em;text-transform:uppercase;font-weight:600;color:var(--accent)}
.lead{font-size:18px;color:var(--muted);max-width:62ch}
.section{margin-top:56px}
.section > h2{font-size:clamp(24px,3vw,30px);margin-bottom:8px}
.section > .sub{color:var(--muted);max-width:none;margin-bottom:22px}
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:20px}
.btn{display:inline-flex;align-items:center;gap:6px;font:inherit;font-size:15px;font-weight:500;padding:9px 16px;border-radius:9px;border:1px solid var(--line);background:var(--panel);color:var(--ink);cursor:pointer;text-decoration:none}
.btn:hover{border-color:var(--muted)}
.btn.primary{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}
.btn:disabled{opacity:.4;cursor:default}
.chip{display:inline-block;font-size:12px;padding:3px 9px;border-radius:999px;background:var(--chip);color:var(--ink);font-weight:500}
.site-foot{border-top:1px solid var(--line);padding-block:24px;color:var(--muted);font-size:14px}
.site-foot .wrap{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}
.site-foot small{font-size:12.5px}

/* ============ About page ============ */
.hero{display:grid;grid-template-columns:minmax(0,1.35fr) minmax(0,1fr);gap:40px;align-items:center}
.hero h1{font-size:clamp(32px,4.6vw,50px);margin:10px 0 16px}
.hero .actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:24px}
.portrait{border-radius:18px;overflow:hidden;border:1px solid var(--line);aspect-ratio:800/655;background:var(--chip);align-self:center}
.portrait img{width:100%;height:100%;object-fit:cover}
@media (max-width:820px){.hero{grid-template-columns:1fr}.portrait{max-width:420px}}
.stats{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px;margin-top:40px}
.stat{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:18px 20px}
.stat b{display:block;font-family:var(--serif);font-size:34px;line-height:1.1;font-weight:650}
.stat span{color:var(--muted);font-size:14px}
@media (max-width:640px){.stats{grid-template-columns:1fr}}
.two{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
@media (max-width:760px){.two{grid-template-columns:1fr}}
.card h3{font-size:21px;margin-bottom:8px}
.card p + p{margin-top:10px}
.card ul{margin:10px 0 0;padding-left:20px}
.card li + li{margin-top:4px}
.timeline{list-style:none;margin:0;padding:0;display:grid;gap:0}
.timeline li{display:grid;grid-template-columns:96px 1fr;gap:16px;padding:12px 0;border-bottom:1px solid var(--grid)}
.timeline li:last-child{border-bottom:0}
.timeline .yr{font-family:var(--mono);font-size:14px;color:var(--accent);font-variant-numeric:tabular-nums;white-space:nowrap}
.timeline .yr i{font-style:normal;color:var(--muted);padding-inline:2px}
.card h3 + .timeline{margin-top:4px}
@media (max-width:520px){.timeline li{grid-template-columns:1fr;gap:2px}}
.prices{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
@media (max-width:760px){.prices{grid-template-columns:1fr}}
.price{display:flex;flex-direction:column;gap:10px}
.price .chip,.ia-card .chip{align-self:flex-start}
.price{transition:transform .18s ease, box-shadow .18s ease, border-color .18s ease}
.price:hover,.price:focus-within{border-color:var(--accent);box-shadow:0 0 0 1px var(--accent) inset, 0 10px 28px rgba(20,40,35,.12);transform:translateY(-3px) scale(1.015)}
@media (prefers-reduced-motion: reduce){.price{transition:none}.price:hover,.price:focus-within{transform:none}}
.offer{background:var(--accent-soft);border-radius:10px;padding:12px 14px;display:grid;gap:8px}
.offer-head{display:flex;justify-content:space-between;align-items:baseline;gap:10px;flex-wrap:wrap;font-size:14px}
.offer-head b:first-child{font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:var(--accent)}
.offer-head span{font-variant-numeric:tabular-nums}
.offer-head #spots-left{font-family:var(--serif);font-size:20px;color:var(--ink)}
.offer-bar{height:8px;border-radius:999px;background:var(--panel);overflow:hidden}
.offer-bar i{display:block;height:100%;background:var(--accent);border-radius:999px}
.offer p{font-size:14.5px}
.price .amount{font-family:var(--serif);font-size:40px;font-weight:650;line-height:1}
.price .amount small{font-family:var(--sans);font-size:15px;font-weight:400;color:var(--muted)}
.price ol{margin:0;padding-left:20px}
.note{font-size:14px;color:var(--muted)}

/* ============ Sample IA ============ */
.ia-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
@media (max-width:900px){.ia-grid{grid-template-columns:1fr}}
.ia-card{display:flex;flex-direction:column;gap:12px;min-height:260px}
.ia-card .ph{flex:1;border:1.5px dashed var(--line);border-radius:10px;display:grid;place-items:center;color:var(--muted);font-size:14px;padding:16px;text-align:center}
.crit{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:10px}
.crit div{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:12px 14px;font-size:14px}
.crit b{display:block;font-family:var(--mono);font-size:13px;color:var(--accent)}

/* ============ Simulation gallery ============ */
.gallery-group{margin-top:36px}
.gallery-group h2{font-size:24px;margin-bottom:14px;display:flex;align-items:baseline;gap:10px}
.gallery-group h2 span{font-family:var(--sans);font-size:13px;font-weight:500;color:var(--muted);letter-spacing:.06em;text-transform:uppercase}
.gallery{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}
@media (max-width:900px){.gallery{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:560px){.gallery{grid-template-columns:1fr}}
.tile{display:flex;flex-direction:column;background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;text-decoration:none;color:var(--ink);transition:border-color .15s, transform .15s}
.tile:hover{border-color:var(--accent);transform:translateY(-2px)}
.tile svg{width:100%;height:auto;background:var(--bg);border-bottom:1px solid var(--line)}
.tile .t{padding:14px 16px 16px;display:grid;gap:4px}
.tile h3{font-size:19px}
.tile p{font-size:14px;color:var(--muted)}
.tile .code{font-family:var(--mono);font-size:12px;color:var(--accent)}

/* ============ Simulation player (v2, compact) ============ */
.sim-head{display:grid;gap:6px;margin-bottom:18px}
.sim-head h1{font-size:clamp(28px,3.6vw,38px)}
.crumb{font-size:14px;color:var(--muted)}
.crumb a{color:var(--muted)}
/* compact page head on simulation pages */
body.has-sim main{padding-block:14px 40px}
body.has-sim .sim-head{gap:2px;margin-bottom:10px}
body.has-sim .sim-head .crumb{font-size:13px}
body.has-sim .sim-head h1{font-size:clamp(22px,2.6vw,28px)}
body.has-sim .sim-head .lead{font-size:14.5px;max-width:none;line-height:1.45}
/* bar above the diagram: scenarios left, settings right */
.sim-bar{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:8px 16px;margin-bottom:10px}
.sim-bar.solo .scen{display:none}
.sim-bar.solo{justify-content:flex-end}
.scen{display:flex;flex-wrap:wrap;gap:6px}
.scen button{font:inherit;font-size:13.5px;border:1px solid var(--line);background:var(--panel);color:var(--ink);padding:6px 12px;border-radius:999px;cursor:pointer}
.scen button[aria-selected="true"]{background:var(--ink);color:var(--bg);border-color:var(--ink)}
.sim-tools{display:flex;align-items:center;gap:14px;margin-left:auto}
.speed{display:flex;align-items:center;gap:8px;font-size:12.5px;color:var(--muted)}
.speed input{width:110px;accent-color:var(--accent)}
.kbd{font-family:var(--mono);font-size:11.5px;color:var(--muted)}
/* stage */
.stage{display:grid;grid-template-columns:minmax(0,1.6fr) minmax(290px,1fr);gap:14px;align-items:start}
@media (max-width:860px){.stage{grid-template-columns:1fr}}
.stage.wide{grid-template-columns:1fr}
.stage.wide .side{grid-template-columns:minmax(0,1.4fr) minmax(0,1fr);align-items:start}
@media (max-width:760px){.stage.wide .side{grid-template-columns:1fr}}
.fig{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:8px;position:relative}
.fig svg{display:block;width:100%;height:auto;max-height:calc(100svh - 235px);min-height:260px}
.stage.wide .fig svg{max-height:calc(100svh - 290px)}
.sim-bar.has-ctl{display:grid;grid-template-columns:1fr auto;align-items:center}
.sim-bar.has-ctl .scen{grid-column:1 / -1}
.bar-ctl{display:flex;align-items:center;gap:12px}
.bar-ctl .step-meta{gap:8px}
.fig svg text{font-family:var(--sans);fill:var(--muted);font-size:12.5px}
.fig svg .clabel{font-weight:600;font-size:13.5px}
.fig svg .clabel,.fig svg .area-lab,.fig svg .tick,.fig svg .ptlab{paint-order:stroke;stroke:var(--panel);stroke-width:4px;stroke-linejoin:round}
.fig svg .tick{font-family:var(--mono);font-size:12px;fill:var(--ink)}
.fig svg .ptlab{font-family:var(--mono);font-weight:600;fill:var(--ink)}
.fig svg .area-lab{font-weight:600;font-size:12.5px;fill:var(--ink)}
.fig svg .box-t{font-size:13px;fill:var(--ink);font-weight:500}
.fig svg .badge{cursor:pointer;outline:none}
.fig svg .badge-hit{fill:transparent}
.fig svg .badge-c{fill:var(--ink);transition:fill .2s}
.fig svg .badge-t{fill:var(--bg);font-family:var(--mono);font-weight:600;font-size:12px;pointer-events:none}
.fig svg .badge.on .badge-c,.fig svg .badge:focus-visible .badge-c{fill:var(--accent)}
.fig svg .panel-title{font-size:11.5px;letter-spacing:.08em;text-transform:uppercase;font-weight:600;fill:var(--muted)}
.legend{display:flex;flex-wrap:wrap;gap:4px 14px;font-size:12.5px;color:var(--muted);padding:6px 6px 0}
.legend span::before{content:"";display:inline-block;width:14px;height:3px;border-radius:2px;margin-right:6px;vertical-align:middle;background:var(--c)}
.legend span.box::before{height:10px;width:12px;border-radius:2px}
/* running silver outline around the elements a note talks about */
.hl-el{pointer-events:none}
.hl-el .hl-base{fill:none;stroke:#aeb6bb;stroke-width:2.2;opacity:.9}
.hl-el .hl-run{fill:none;stroke:#f7f9fa;stroke-width:2.2;stroke-dasharray:16 44;stroke-linecap:round;animation:hl-run 1.3s linear infinite;filter:drop-shadow(0 0 2px rgba(142,151,157,.95))}
.hl-path .hl-base{stroke-width:7;stroke:#aeb6bb;opacity:.55;stroke-linecap:round;stroke-linejoin:round}
.hl-path .hl-run{stroke-width:4;stroke-dasharray:22 38}
@keyframes hl-run{to{stroke-dashoffset:-60}}
@media (prefers-reduced-motion: reduce){.hl-el .hl-run{animation:none;stroke-dasharray:none;stroke:#8e979d}}
/* speech bubbles on the diagram */
.bubbles{position:absolute;inset:0;pointer-events:none;z-index:3}
.bubble{position:absolute;pointer-events:auto;background:var(--panel);color:var(--ink);border:1px solid var(--line);border-top:3px solid var(--accent);border-radius:10px;padding:9px 12px 10px;box-shadow:0 8px 24px rgba(20,30,35,.16),0 1px 3px rgba(20,30,35,.12);display:grid;grid-template-columns:auto 1fr;gap:2px 8px;font-size:13.5px;line-height:1.45;animation:bub .28s ease both}
.bubble .n{grid-row:span 2;width:20px;height:20px;border-radius:50%;background:var(--accent);color:var(--accent-ink,#fff);font-family:var(--mono);font-weight:600;font-size:11px;display:grid;place-items:center;margin-top:1px}
.bubble .tag{font-size:10.5px;letter-spacing:.08em;text-transform:uppercase;font-weight:600;color:var(--muted)}
.bubble::before{content:"";position:absolute;width:12px;height:12px;background:var(--panel);border:1px solid var(--line);transform:rotate(45deg)}
.bubble[data-side="r"]::before{left:-7px;top:calc(var(--tail) - 6px);border-right:0;border-top:0}
.bubble[data-side="l"]::before{right:-7px;top:calc(var(--tail) - 6px);border-left:0;border-bottom:0}
.bubble[data-side="b"]::before{top:-8px;left:calc(var(--tail) - 6px);border-right:0;border-bottom:0}
.bubble[data-side="t"]::before{bottom:-7px;left:calc(var(--tail) - 6px);border-left:0;border-top:0}
.bubble.t-price{border-top-color:var(--c-d)}.bubble.t-qty{border-top-color:var(--c-s)}.bubble.t-welfare{border-top-color:var(--c-alt)}.bubble.t-eval{border-top-color:var(--c-pt)}
@keyframes bub{from{opacity:0;transform:scale(.94)}to{opacity:1;transform:none}}
@media (prefers-reduced-motion: reduce){.bubble{animation:none}}
/* step card */
.side{display:grid;gap:10px}
.step-card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:12px 16px 14px;display:grid;gap:8px}
.step-meta{display:flex;align-items:center;justify-content:space-between;gap:10px;font-family:var(--mono);font-size:12px;color:var(--muted)}
.dots{display:flex;gap:5px}
.dots i{width:9px;height:9px;border-radius:50%;background:var(--line);cursor:pointer}
.dots i.on{background:var(--accent)}
.controls{display:flex;flex-wrap:wrap;gap:6px}
.controls .btn{padding:7px 12px;font-size:14px}
.controls .ctl-step{display:none}
.step-card h2{font-size:19px;margin-top:2px}
.step-card p{color:var(--ink);max-width:62ch;font-size:15px;line-height:1.5}
.cl-chips{display:flex;flex-wrap:wrap;gap:6px}
.chip-n{font:inherit;font-size:12.5px;display:inline-flex;align-items:center;gap:6px;border:1px solid var(--line);background:var(--bg);color:var(--ink);border-radius:999px;padding:3px 10px 3px 4px;cursor:pointer}
.chip-n .n{width:18px;height:18px;border-radius:50%;background:var(--ink);color:var(--bg);font-family:var(--mono);font-size:10.5px;font-weight:600;display:grid;place-items:center}
.chip-n.on{border-color:var(--accent)}.chip-n.on .n{background:var(--accent)}
.cl-notes{display:grid;gap:6px}
.cl-note{font-size:14px!important;border-left:3px solid var(--c-pt);padding:2px 0 2px 10px;color:var(--ink)}
.cl-note b{font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin-right:4px}
.exam-tip{background:var(--accent-soft);border-radius:10px;padding:8px 12px;font-size:13.5px;line-height:1.45}
.exam-tip b{font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--accent);margin-right:4px}
.readout{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:6px 14px}
.readout table{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums;font-size:13.5px}
.readout td{padding:4px 0;border-bottom:1px solid var(--grid)}
.readout tr:last-child td{border-bottom:0}
.readout td:last-child{text-align:right;font-family:var(--mono)}
/* legacy classes (Phillips page, old configs) */
.callouts{display:grid;gap:10px}
@keyframes pop{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
@media (prefers-reduced-motion: reduce){.tile{transition:none}}
/* phones and narrow tablets: step buttons in a fixed bar at the bottom */
@media (max-width:860px){
  body.has-sim{padding-bottom:64px}
  body.has-sim .kbd{display:none}
  .sim .controls{position:fixed;left:0;right:0;bottom:0;z-index:30;justify-content:center;align-items:center;padding:8px 12px calc(8px + env(safe-area-inset-bottom,0px));background:color-mix(in srgb,var(--panel) 94%,transparent);backdrop-filter:blur(8px);border-top:1px solid var(--line)}
  .sim .controls .ctl-step{display:inline;font-family:var(--mono);font-size:12px;color:var(--muted);margin-right:4px}
  .fig svg{max-height:none}
}
@media (max-width:560px){
  .fig{padding:4px}
  .fig svg text{font-size:16px}
  .fig svg .clabel{font-size:17px}
  .fig svg .tick,.fig svg .area-lab{font-size:15px}
  .fig svg .badge-t{font-size:14px}
  .speed input{width:80px}
  .bubble{font-size:13px}
}

.section{scroll-margin-top:84px}
.contact{display:grid;gap:12px;max-width:620px}
.contact-row{display:flex;flex-wrap:wrap;align-items:center;gap:10px 14px}
.addr{font-family:var(--mono);font-size:17px;user-select:all;overflow-wrap:anywhere}
.card .timeline{padding-left:0;margin-top:6px}

.offer-banner{margin:40px auto 0;max-width:760px;text-align:center;background:var(--accent-soft);border:1px solid var(--accent);border-radius:16px;padding:28px 24px;display:grid;gap:12px;justify-items:center;scroll-margin-top:84px}
.offer-banner h2{font-size:clamp(24px,3.2vw,32px)}
.offer-banner p{max-width:56ch;color:var(--ink)}
.offer-count{display:flex;align-items:baseline;gap:8px;font-variant-numeric:tabular-nums}
.offer-count b{font-family:var(--serif);font-size:44px;line-height:1;color:var(--accent)}
.offer-count span{color:var(--muted)}
.offer-banner .offer-bar{width:min(100%,420px);height:10px}
.offer-banner .btn{margin-top:4px}
.site-foot b{color:var(--ink);font-weight:600}
.foot-mail{font-family:var(--mono);font-size:13.5px;user-select:all}

/* ---------- diagram watermark (see Watermark in sim-engine.js) ---------- */
svg .wm{pointer-events:none;user-select:none;-webkit-user-select:none}
svg .wm text.wm-sig{font-family:var(--sans);font-size:12px;font-weight:600;letter-spacing:.04em;fill:var(--ink);fill-opacity:.08;stroke:none}
.fig svg,figure svg{-webkit-user-select:none;user-select:none;-webkit-touch-callout:none}
@media print{svg .wm text.wm-sig{fill-opacity:.16}}

/* ---------- launch-offer pop-up (index.html) ---------- */
.offer-pop{border:1px solid var(--accent);border-radius:16px;background:var(--accent-soft);color:var(--ink);padding:52px 26px 26px;outline:none;width:min(520px,calc(100vw - 32px));max-width:none;text-align:center;box-shadow:0 24px 60px rgba(0,0,0,.28)}
.offer-pop[open]{display:grid;gap:12px;justify-items:center;animation:pop-in .35s ease-out}
.offer-pop::backdrop{background:rgba(12,20,24,.55);backdrop-filter:blur(2px)}
.offer-pop h2{font-size:clamp(22px,4.5vw,28px);text-wrap:balance}
.offer-pop p{max-width:44ch}
.offer-pop-actions{display:flex;flex-wrap:wrap;gap:10px;justify-content:center;margin-top:4px}
.offer-pop-x{position:absolute;top:10px;right:12px;width:36px;height:36px;border-radius:50%;border:1px solid var(--line);background:var(--panel);color:var(--ink);font-size:22px;line-height:1;cursor:pointer}
.offer-pop-x:hover{border-color:var(--muted)}
.offer-pop-x:focus-visible,.offer-pop .btn:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
@keyframes pop-in{from{opacity:0;transform:translateY(12px) scale(.97)}to{opacity:1;transform:none}}
@media (prefers-reduced-motion: reduce){.offer-pop[open]{animation:none}}

/* ---------- sample IAs: marks table + annotated viewer ---------- */
:root{--cA:#7a3e9d;--cB:#0e6b8a;--cC:#1f5f5b;--cD:#a3521b;--cE:#5b5b1f;--cF:#555555;--pip-off:#e3e7e4}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]){--cA:#c79ae0;--cB:#7fc6de;--cC:#6fc2bb;--cD:#e8a06a;--cE:#c9c96a;--cF:#aaaaaa;--pip-off:#2f3a3f}}
:root[data-theme="dark"]{--cA:#c79ae0;--cB:#7fc6de;--cC:#6fc2bb;--cD:#e8a06a;--cE:#c9c96a;--cF:#aaaaaa;--pip-off:#2f3a3f}
.ia-card h3{font-size:20px;text-wrap:balance}
.ia-marks{width:100%;border-collapse:collapse;font-size:14.5px;font-variant-numeric:tabular-nums}
.ia-marks th{font-size:11.5px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-weight:600;text-align:left;padding:0 6px 6px 0;border-bottom:1px solid var(--line)}
.ia-marks td{padding:8px 6px 8px 0;border-bottom:1px solid var(--grid);vertical-align:middle}
.ia-marks td:first-child{width:34px}
.ia-marks .n{text-align:right;font-family:var(--mono);font-weight:600;white-space:nowrap;padding-right:0}
.ia-marks tfoot td{border-bottom:0;font-weight:600;padding-top:10px}
.ia-marks .cl{display:inline-grid;place-items:center;width:24px;height:24px;border-radius:6px;background:var(--c);color:var(--panel);font-family:var(--mono);font-weight:600;font-size:13px}
.ia-marks .pips{display:inline-flex;gap:4px;justify-content:flex-end;width:100%}
.ia-marks .pips i{width:12px;height:12px;border-radius:3px;background:var(--pip-off)}
.ia-marks .pips i.on{background:var(--c)}
.ia-marks tr.cA{--c:var(--cA)}.ia-marks tr.cB{--c:var(--cB)}.ia-marks tr.cC{--c:var(--cC)}.ia-marks tr.cD{--c:var(--cD)}.ia-marks tr.cE{--c:var(--cE)}.ia-marks tr.cF{--c:var(--cF)}
.ia-eval{font-size:15px;line-height:1.6;color:var(--ink)}
.ia-card .ia-open{align-self:flex-start;margin-top:auto}
.ia-viewer{border:1px solid var(--line);border-radius:14px;background:var(--panel);color:var(--ink);padding:0;width:min(1100px,calc(100vw - 32px));max-width:none;height:min(92vh,1400px);max-height:none;box-shadow:0 24px 60px rgba(0,0,0,.3)}
.ia-viewer[open]{display:flex;flex-direction:column}
.ia-viewer::backdrop{background:rgba(12,20,24,.6)}
.ia-viewer-head{display:flex;align-items:center;gap:12px;padding:12px 16px;border-bottom:1px solid var(--line);position:relative}
.ia-viewer-head h2{font-size:17px;flex:1;margin:0;padding-right:40px;text-wrap:balance}
.ia-viewer-head .offer-pop-x{position:static;flex:none}
.ia-viewer-body{flex:1;overflow:auto;background:var(--bg);padding:16px;display:grid;gap:16px;justify-items:center}
.ia-viewer-body img{width:100%;max-width:1040px;height:auto;border-radius:4px;box-shadow:0 2px 12px rgba(0,0,0,.15);user-select:none;-webkit-user-drag:none}
.crit div:nth-child(1) b{color:var(--cA)}.crit div:nth-child(2) b{color:var(--cB)}.crit div:nth-child(3) b{color:var(--cC)}.crit div:nth-child(4) b{color:var(--cD)}.crit div:nth-child(5) b{color:var(--cE)}.crit div:nth-child(6) b{color:var(--cF)}

.section > h2{text-wrap:pretty}

/* ---------- book a lesson ---------- */
.book{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,1fr);border:1px solid var(--line);border-radius:16px;overflow:hidden;background:var(--panel)}
.book-mail{background:var(--accent-soft);padding:28px;display:grid;gap:12px;align-content:center}
.book-label{font-size:13px;font-weight:600;letter-spacing:.06em;text-transform:uppercase;color:var(--accent)}
.book .addr{font-family:var(--sans);font-size:clamp(18px,2.4vw,24px);font-weight:600;color:var(--ink)}
.book-actions{display:flex;flex-wrap:wrap;gap:10px}
.book-actions .btn:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
#copy-msg:empty{display:none}
.book-tips{padding:28px;display:grid;gap:14px;align-content:start}
.book-tips h3{font-size:19px}
.book-list{list-style:none;margin:0;padding:0;display:grid;gap:10px}
.book-list li{display:grid;grid-template-columns:22px 1fr;column-gap:10px;align-items:baseline}
.book-list li::before{content:"";grid-row:span 2;width:16px;height:16px;border-radius:50%;background:var(--accent-soft);border:1.5px solid var(--accent);align-self:start;margin-top:3px;box-shadow:inset 0 0 0 3px var(--panel)}
.book-list b{font-weight:600}
.book-list span{color:var(--muted);font-size:14.5px}
@media (max-width:760px){.book{grid-template-columns:1fr}.book-mail,.book-tips{padding:22px 18px}}

.offer-actions{display:flex;flex-wrap:wrap;gap:10px;justify-content:center}
.offer-banner .offer-actions .btn{margin-top:4px}

/* ---------- sample IA page: compact so the open button is visible on load ---------- */
.ia-page .sim-head{gap:4px;margin-bottom:14px}
.ia-page .sim-head h1{font-size:clamp(24px,3vw,32px)}
.ia-page .sim-head .lead{font-size:15.5px;max-width:none}
.ia-page .ia-card{gap:8px;min-height:0;padding:18px}
.ia-page .ia-card h3{font-size:17.5px}
.ia-page .ia-card .note{font-size:13px}
.ia-page .ia-marks{font-size:13.5px}
.ia-page .ia-marks td{padding:4px 6px 4px 0}
.ia-page .ia-marks tfoot td{padding-top:6px}
.ia-page .ia-marks .cl{width:20px;height:20px;font-size:12px}
.ia-page .ia-eval{font-size:14px;line-height:1.5}
.ia-page .ia-card .ia-open{margin-top:0}
.ia-page .ia-card .ia-open{margin-block:2px 6px}

/* ---------- popup: one slow silver sweep around "Claim your place" ---------- */
@property --sweep{syntax:"<angle>";inherits:false;initial-value:0deg}
#offer-pop-claim{position:relative}
#offer-pop-claim::after{content:"";position:absolute;inset:-4px;border-radius:13px;padding:2.5px;pointer-events:none;opacity:0;
  background:conic-gradient(from var(--sweep),transparent 0deg 250deg,#8e979d 285deg,#f7f9fa 320deg,#c3cacf 340deg,transparent 360deg);
  -webkit-mask:linear-gradient(#000 0 0) content-box,linear-gradient(#000 0 0);-webkit-mask-composite:xor;
  mask:linear-gradient(#000 0 0) content-box exclude,linear-gradient(#000 0 0)}
.offer-pop[open] #offer-pop-claim::after{animation:silver-sweep 2.6s cubic-bezier(.45,0,.55,1) .45s 1 both}
@keyframes silver-sweep{0%{--sweep:0deg;opacity:0}8%{opacity:1}88%{opacity:1}100%{--sweep:360deg;opacity:0}}
@media (prefers-reduced-motion: reduce){.offer-pop[open] #offer-pop-claim::after{animation:none}}

/* 4-item nav: one line on phones, scrolls sideways if still too narrow */
@media (max-width:560px){.nav{gap:0;flex-wrap:nowrap;overflow-x:auto;max-width:100%;scrollbar-width:none;margin-inline:-4px}.nav::-webkit-scrollbar{display:none}.nav a{padding:5px 5px;font-size:12px;white-space:nowrap;flex:none}}
/* Pricing: "every lesson is individual" highlight (2026-09-26) */
.unique{display:flex;gap:16px;align-items:center;margin:0 0 18px;padding:16px 20px;background:var(--accent-soft);border:1px solid var(--accent);border-left-width:5px;border-radius:var(--radius)}
.unique p{margin:0;font-size:16px;line-height:1.5;color:var(--ink)}
.unique b{font-weight:650}
.unique-mark{flex:none;display:grid;place-items:center;width:52px;height:52px;border-radius:50%;background:var(--accent);color:var(--accent-ink);font-family:var(--mono);font-weight:600;font-size:15px}
@media (max-width:520px){.unique{padding:14px}.unique-mark{width:42px;height:42px;font-size:13px}.unique p{font-size:15px}}
/* Phone: menu wraps to two rows instead of scrolling, so the full "Business & Management (beta)" label stays visible (2026-09-26) */
@media (max-width:560px){.nav{flex-wrap:wrap;overflow-x:visible;row-gap:2px;margin-inline:-4px}.nav a{padding:5px 8px;font-size:13px}}
.site-foot .foot-links{align-self:flex-end}.site-foot .foot-links a{color:var(--muted)}.site-foot .foot-links a:hover{color:var(--ink)}
/* IA rules handout: call-out on Sample IAs + pop-up (2026-09-26) */
.handout-cta{display:grid;grid-template-columns:auto 1fr auto;gap:18px;align-items:center;margin:4px 0 22px;padding:16px 20px;background:var(--accent-soft);border:1px solid var(--accent);border-left-width:5px;border-radius:14px}
.handout-cta h2{font-size:clamp(19px,2.6vw,23px);margin:2px 0 4px;text-wrap:balance}
.handout-cta p{margin:0;color:var(--ink);font-size:14.5px}
.handout-thumb{width:84px;height:auto;border-radius:4px;box-shadow:0 2px 10px rgba(0,0,0,.18);transform:rotate(-3deg);background:#fff}
.handout-btns{display:flex;flex-direction:column;gap:8px}
@media (max-width:760px){.handout-cta{grid-template-columns:auto 1fr}.handout-btns{grid-column:1/-1;flex-direction:row;flex-wrap:wrap}}
@media (max-width:420px){.handout-thumb{width:60px}}
.handout-pop{width:min(620px,calc(100vw - 32px))}
.handout-pages{display:grid;grid-template-columns:1fr 1fr;gap:10px;width:100%;margin:4px 0}
.handout-pages img{width:100%;border-radius:4px;box-shadow:0 2px 10px rgba(0,0,0,.18);background:#fff;user-select:none}
/* ---------- Calculators (2026-09-26) ---------- */
.calc-filter{display:flex;gap:6px;flex-wrap:wrap;margin:6px 0 18px}
.calc-filter button{font:500 14px var(--sans);border:1px solid var(--line);background:var(--panel);color:var(--ink);border-radius:999px;padding:6px 14px;cursor:pointer}
.calc-filter button.on{background:var(--ink);color:var(--bg);border-color:var(--ink)}
.calc-list{display:flex;flex-direction:column;gap:22px;margin-bottom:40px}
.calc-card{padding:22px 24px}
.calc-head h2{margin:6px 0 4px}
.calc-head .sub{margin:0 0 14px;max-width:none}
.calc-tags{display:flex;gap:6px;flex-wrap:wrap}
.calc-body{display:grid;grid-template-columns:minmax(230px,300px) minmax(0,1fr);gap:22px;align-items:start}
@media (max-width:860px){.calc-body{grid-template-columns:1fr}}
.calc-in{display:flex;flex-direction:column;gap:10px;position:sticky;top:calc(env(safe-area-inset-top,0px) + 76px)}
@media (max-width:860px){.calc-in{position:static}}
.calc-field{display:grid;grid-template-columns:auto 1fr;grid-template-rows:auto auto;column-gap:8px;row-gap:3px;align-items:center}
.calc-sym{grid-row:1;font-size:15px}.calc-sym .katex-display{margin:0}.calc-sym .katex{font-size:1em}
.calc-label{grid-row:1;font-size:13px;color:var(--muted)}
.calc-box{grid-column:1/-1;display:flex;align-items:center;border:1px solid var(--line);border-radius:9px;background:var(--panel);position:relative}
.calc-box input{flex:1;min-width:0;border:0;background:none;font:500 15px var(--mono);color:var(--ink);padding:7px 10px;font-variant-numeric:tabular-nums}
.calc-box input:focus{outline:none}.calc-box:focus-within{border-color:var(--accent);box-shadow:0 0 0 2px var(--accent-soft)}
.calc-unit{font-size:12px;color:var(--muted);padding-right:10px;white-space:nowrap}
.calc-in .btn{align-self:flex-start;font-size:13px;padding:6px 12px}
.calc-out{min-width:0;display:flex;flex-direction:column;gap:6px}
.calc-group{font:600 12px var(--sans);letter-spacing:.09em;text-transform:uppercase;color:var(--accent);margin:12px 0 2px;padding-top:10px;border-top:1px solid var(--line)}
.calc-group:first-child{margin-top:0;padding-top:0;border-top:0}
.calc-step{border-radius:10px;padding:6px 10px;transition:background .15s}
.calc-step:hover{background:var(--accent-soft)}
.calc-slabel{font-size:13px;color:var(--muted)}
.calc-math{overflow-x:auto;overflow-y:hidden;padding:2px 0}
.calc-math .katex-display{margin:.2em 0;text-align:left}
.calc-math .katex-display>.katex{text-align:left;font-size:1.12em}
.calc-note{font-size:13px;color:var(--ink);opacity:.85}
.calc-error{padding:12px 14px;border:1px solid var(--c-down);border-radius:10px;color:var(--c-down)}
.calc-card [data-res],.calc-card [data-ref],.calc-card [data-mid]{cursor:help;border-radius:4px;position:relative;transition:background .15s}
.calc-card [data-ref]:hover,.calc-card [data-mid]:hover,.calc-card [data-res].hot{background:rgba(217,162,27,.22)}
/* the silver sweep around the numbers a result was built from */
.calc-card .glow{background:rgba(142,151,157,.16)}
.calc-card .glow::after{content:"";position:absolute;inset:-4px -5px;border-radius:7px;padding:2px;pointer-events:none;
  background:conic-gradient(from var(--sweep),transparent 0deg 200deg,#8e979d 250deg,#f7f9fa 300deg,#c3cacf 330deg,transparent 360deg);
  -webkit-mask:linear-gradient(#000 0 0) content-box,linear-gradient(#000 0 0);-webkit-mask-composite:xor;mask:linear-gradient(#000 0 0) content-box exclude,linear-gradient(#000 0 0);
  animation:calc-sweep 1.5s linear infinite}
.calc-box.glow::after{inset:-4px;border-radius:12px}
@keyframes calc-sweep{from{--sweep:0deg}to{--sweep:360deg}}
@media (prefers-reduced-motion: reduce){.calc-card .glow::after{animation:none;background:#8e979d}}
.lorenz{margin:4px 0 8px;max-width:380px}.lorenz svg{width:100%;height:auto;display:block}
.lz-grid{stroke:var(--grid);stroke-width:1}.lz-t{font:11px var(--sans);fill:var(--muted)}
.lz-eq{stroke:var(--ink);stroke-width:1.4}.lz-curve{fill:none;stroke:var(--c-d);stroke-width:2.4}
.lz-a{fill:var(--f-cs)}.lz-pt{fill:var(--c-pt);stroke:var(--ink);stroke-width:1}.lz-lab{font:italic 12px var(--serif);fill:var(--ink)}
.calc-interp{margin-top:6px;padding:12px 16px 6px;border:1px solid var(--accent);border-left-width:4px;border-radius:10px;background:var(--accent-soft)}
.calc-interp .calc-group{margin:0 0 6px;padding:0;border:0}
.calc-interp p{margin:0 0 8px;font-size:15px;line-height:1.55}
.calc-interp b[data-ref]{font-family:var(--mono);font-weight:600;padding:0 2px}
.calc-field:has(input[type=text]) .calc-box input{font-family:var(--sans)}
/* calculators: diagrams with measurable areas */
.calc-fig{margin:4px 0 10px;max-width:460px}.calc-fig svg{width:100%;height:auto;display:block;overflow:visible}
.cf-grid{stroke:var(--grid);stroke-width:1}.cf-axis{stroke:var(--ink);stroke-width:1.4;fill:none}
.cf-t{font:11px var(--sans);fill:var(--muted)}.cf-lab{font:600 12px var(--sans);fill:var(--ink)}
.cf-d{stroke:var(--c-d);stroke-width:2.4;fill:none}.cf-s{stroke:var(--c-s);stroke-width:2.4;fill:none}.cf-x{stroke:var(--c-alt);stroke-width:2.2;fill:none;stroke-dasharray:6 4}
.cf-h{stroke:var(--ink);stroke-width:1.6}.cf-guide{stroke:var(--muted);stroke-width:1;stroke-dasharray:3 4}
.calc-card svg [data-area]{cursor:help;stroke:transparent;stroke-width:3;transition:fill-opacity .15s}
.calc-card svg [data-area]:hover,.calc-card svg [data-area].hot{fill-opacity:1}
.a-cs{fill:var(--f-cs)}.a-ps{fill:var(--f-ps)}.a-gov{fill:var(--f-gov)}.a-dwl{fill:var(--f-dwl)}.a-tr{fill:var(--f-tr)}.a-gain{fill:var(--f-gain)}
.calc-card svg [data-area].glow{stroke:#7b858b;stroke-width:4.5;stroke-linejoin:round;stroke-linecap:round;stroke-dasharray:34 66;animation:area-run 1.3s linear infinite;fill-opacity:1;filter:drop-shadow(0 0 1.5px #fff) drop-shadow(0 0 3px rgba(142,151,157,.9))}
.calc-card svg [data-area].glow::after{content:none}
@keyframes area-run{from{stroke-dashoffset:0}to{stroke-dashoffset:-100}}
@media (prefers-reduced-motion: reduce){.calc-card svg [data-area].glow{animation:none;stroke-dasharray:none}}
.calc-step.hot{background:var(--accent-soft)}
/* calculators page: index + one calculator at a time */
.calc-page{display:grid;grid-template-columns:250px minmax(0,1fr);gap:24px;align-items:start;margin-bottom:40px}
@media (max-width:900px){.calc-page{grid-template-columns:1fr}}
.calc-index{position:sticky;top:calc(env(safe-area-inset-top,0px) + 76px);max-height:calc(100vh - 100px);overflow:auto;display:flex;flex-direction:column;gap:2px;padding-right:4px}
@media (max-width:900px){.calc-index{position:static;max-height:none}}
.calc-index h4{font:600 11px var(--sans);letter-spacing:.09em;text-transform:uppercase;color:var(--muted);margin:12px 0 4px}
.calc-index h4:first-child{margin-top:0}
.calc-index a{display:block;padding:5px 10px;border-radius:8px;color:var(--ink);text-decoration:none;font-size:14px;line-height:1.3}
.calc-index a:hover{background:var(--chip)}.calc-index a[aria-current="true"]{background:var(--ink);color:var(--bg)}
.calc-index .hl{font:600 10px var(--mono);color:var(--muted);margin-left:4px}
.calc-index a[aria-current="true"] .hl{color:var(--bg)}
.calc-table{border-collapse:collapse;font-size:13.5px;margin:4px 0 10px;font-variant-numeric:tabular-nums}
.calc-table th,.calc-table td{border-bottom:1px solid var(--line);padding:4px 10px;text-align:right}
.calc-table th:first-child,.calc-table td:first-child{text-align:left}
.calc-table .neg{color:var(--c-down)}
.calc-verdict{font-weight:600}

/* Econ simulations: three topic columns side by side (2026-09-26) */
.gallery-cols{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px;align-items:start;margin-top:36px}
.gallery-cols .gallery-group{margin-top:0}
.gallery-cols .gallery-group h2{flex-direction:column;align-items:flex-start;gap:2px;padding-bottom:10px;border-bottom:2px solid var(--accent)}
.gallery-cols .gallery{grid-template-columns:1fr}
@media (max-width:900px){.gallery-cols{grid-template-columns:1fr;gap:0}.gallery-cols .gallery-group{margin-top:32px}.gallery-cols .gallery{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:560px){.gallery-cols .gallery{grid-template-columns:1fr}}
/* compact tiles in the three-column gallery (2026-09-27) */
.gallery-cols .gallery{gap:8px}
.gallery-cols .tile{display:grid;grid-template-columns:112px minmax(0,1fr);align-items:stretch}
.gallery-cols .tile svg{width:112px;height:100%;min-height:74px;border-bottom:0;border-right:1px solid var(--line);padding:4px 2px}
.gallery-cols .tile .t{padding:8px 12px 10px;gap:2px;align-content:start}
.gallery-cols .tile h3{font-size:15.5px;line-height:1.2}
.gallery-cols .tile p{font-size:12.5px;line-height:1.4;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.gallery-cols .tile .code{font-size:11px}
.gallery-cols .tile:hover{transform:translateX(2px)}
@media (max-width:900px){.gallery-cols .gallery{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:560px){.gallery-cols .gallery{grid-template-columns:1fr}}
/* v3 engine: extension marker, pending note chips */
.ext-pill{position:absolute;top:10px;right:12px;z-index:2;font-size:11px;letter-spacing:.06em;text-transform:uppercase;font-weight:600;color:var(--c-alt);background:color-mix(in srgb,var(--c-alt) 12%,var(--panel));border:1px solid color-mix(in srgb,var(--c-alt) 45%,transparent);border-radius:999px;padding:4px 10px;pointer-events:none}
.ext-note{margin:0;font-size:13.5px;line-height:1.45;border-left:3px solid var(--c-alt);padding:4px 0 4px 10px;background:color-mix(in srgb,var(--c-alt) 8%,transparent);border-radius:0 8px 8px 0}
.ext-note b{font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--c-alt);margin-right:4px}
.chip-n.pending{opacity:.45;border-style:dashed}
.chip-n.pending .n{background:var(--muted)}
.fig svg .pay{font-family:var(--mono);font-size:15px;font-weight:600;paint-order:stroke;stroke:var(--panel);stroke-width:4px;stroke-linejoin:round}
.hl-ring .hl-run{stroke-dasharray:20 10}

/* keep the step buttons still while the step/note counter text changes */
.bar-ctl .step-meta > span{display:inline-block;min-width:30ch}
.controls .btn.primary{min-width:9.6em;justify-content:center}
.sim .controls .ctl-step{min-width:10ch}

/* calculator finder */
.calc-find{display:grid;gap:10px;margin:0 0 18px;padding:14px 16px;background:var(--panel);border:1px solid var(--line);border-radius:var(--radius)}
.calc-search{display:grid;gap:4px;font:600 12px var(--sans);letter-spacing:.06em;text-transform:uppercase;color:var(--muted)}
.calc-search input{font:400 15px var(--sans);letter-spacing:0;text-transform:none;color:var(--ink);background:var(--bg);border:1px solid var(--line);border-radius:9px;padding:9px 12px;width:100%}
.calc-search input:focus{outline:2px solid var(--accent);outline-offset:1px}
.calc-need{display:flex;flex-wrap:wrap;gap:6px;align-items:center}
.calc-need-lab{font-size:13px;color:var(--muted);margin-right:2px}
.calc-need button{font:500 13px var(--sans);border:1px solid var(--line);background:var(--bg);color:var(--ink);border-radius:999px;padding:5px 11px;cursor:pointer}
.calc-need button.on{background:var(--accent);border-color:var(--accent);color:var(--accent-ink,#fff)}
.calc-count{margin:0;font-size:13px;color:var(--muted);min-height:1em}

/* calculators: groups as blocks; long calculations get the inputs on top */
.calc-sec{display:flex;flex-direction:column;gap:6px;min-width:0}
.calc-sec + .calc-sec{border-top:1px solid var(--line);padding-top:10px;margin-top:6px}
.calc-sec .calc-group{margin:0 0 2px;padding:0;border:0}
.calc.stacked .calc-body{grid-template-columns:1fr}
.calc.stacked .calc-in{position:static;display:grid;grid-template-columns:repeat(auto-fill,minmax(190px,1fr));gap:10px 16px;align-items:end;padding-bottom:14px;border-bottom:1px solid var(--line)}
.calc.stacked .calc-in .btn{align-self:end;justify-self:start}
.calc.stacked .calc-out{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,380px),1fr));gap:14px 26px;align-items:start}
.calc.stacked .calc-sec.wide{grid-column:1 / -1;border-left:0;padding-left:0}
.calc.stacked .calc-math .katex-display>.katex{font-size:1.02em}
.calc.stacked .calc-sec + .calc-sec{border-top:0;padding-top:0;margin-top:0}
.calc.stacked .calc-sec{border-left:1px solid var(--line);padding-left:16px}
.calc.stacked .calc-sec:first-child{border-left:0;padding-left:0}
.calc.stacked .calc-after{grid-column:1 / -1}
@media (max-width:860px){.calc.stacked .calc-sec{border-left:0;padding-left:0}}

/* the calculators page uses more of a wide screen */
body:has(.calc-page) .wrap{max-width:1380px}
.calc.stacked .calc-sec.wide.cols{display:block;columns:330px 3;column-gap:28px}
.calc.stacked .calc-sec.wide.cols > *{break-inside:avoid;margin-bottom:6px}
.calc.stacked .calc-sec.wide.cols > .calc-group{column-span:all}
@media (max-width:560px){.calc.stacked .calc-in{grid-template-columns:repeat(2,minmax(0,1fr));gap:8px 10px}}

/* diagram calculators: diagram on the left, numbered accordion of calculations on the right */
.calc.diag.stacked .calc-out{display:grid;grid-template-columns:minmax(0,.95fr) minmax(0,1.05fr);gap:20px 28px;align-items:start}
.calc.diag .calc-fig{position:sticky;top:calc(env(safe-area-inset-top,0px) + 76px);display:flex;flex-direction:column;gap:8px;min-width:0}
.calc.diag .calc-acc{display:flex;flex-direction:column;gap:8px;min-width:0}
.calc.diag.stacked .calc-acc .calc-sec{border:1px solid var(--line);border-radius:10px;padding:0;margin:0;background:var(--panel);gap:0}
.calc.diag.stacked .calc-acc .calc-sec:first-child{border-left:1px solid var(--line);padding-left:0}
.calc-acc-h{all:unset;box-sizing:border-box;width:100%;display:flex;align-items:center;gap:10px;padding:10px 14px;cursor:pointer;font:600 13px var(--sans);letter-spacing:.07em;text-transform:uppercase;color:var(--accent);border-radius:10px}
.calc-acc-h:hover{background:var(--chip)}
.calc-acc-h:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.calc-acc-h .n{width:22px;height:22px;border-radius:50%;display:grid;place-items:center;background:var(--muted);color:var(--bg);font:600 12px var(--mono);letter-spacing:0;flex:none}
.calc-acc .open .calc-acc-h .n{background:var(--accent)}
.calc-acc-h .t{flex:1}
.calc-acc-h .chev{width:8px;height:8px;border-right:2px solid currentColor;border-bottom:2px solid currentColor;transform:rotate(45deg);transition:transform .2s;margin-right:4px}
.calc-acc .open .calc-acc-h .chev{transform:rotate(-135deg)}
.calc-acc-b{display:none;padding:2px 12px 12px;flex-direction:column;gap:6px}
.calc-acc .open .calc-acc-b{display:flex}
.calc.diag .calc-acc .calc-math .katex-display>.katex{font-size:1em}
.calc.diag .calc-after{margin-top:4px}
@media (max-width:860px){.calc.diag.stacked .calc-out{grid-template-columns:1fr}.calc.diag .calc-fig{position:static}}
.calc.accm .calc-acc .calc-sec{border:1px solid var(--line);border-radius:10px;padding:0;margin:0;background:var(--panel);gap:0}
.calc.accm .calc-acc .calc-sec + .calc-sec{border-top:1px solid var(--line);padding-top:0;margin-top:0}
/* KaTeX stacks invisible layers over fractions: let the pointer reach the numbers */
.calc-math .katex *{pointer-events:none}
.calc-math [data-ref],.calc-math [data-ref] *,.calc-math [data-mid],.calc-math [data-mid] *,.calc-math [data-res],.calc-math [data-res] *,.calc-math [data-sym],.calc-math [data-sym] *{pointer-events:auto}
/* a parameter or result on the diagram: running silver line */
.calc-card svg .p-run{fill:none;stroke:#f7f9fa;stroke-width:4;stroke-dasharray:18 22;stroke-linecap:round;pointer-events:none;animation:p-run 1.1s linear infinite;filter:drop-shadow(0 0 2px rgba(120,130,136,1)) drop-shadow(0 0 4px rgba(142,151,157,.9))}
.calc-card svg circle.p-run{stroke-dasharray:10 8;stroke-width:3}
.calc-card svg [data-p].glow{filter:drop-shadow(0 0 3px rgba(142,151,157,.9))}
.calc-acc-h.glow{background:rgba(142,151,157,.16);box-shadow:0 0 0 2px #aeb6bb inset}
@keyframes p-run{to{stroke-dashoffset:-40}}
@media (prefers-reduced-motion: reduce){.calc-card svg .p-run{animation:none;stroke-dasharray:none;stroke:#8e979d}}
.calc-card svg .lz-seg{stroke:transparent;stroke-width:1}

.calc-card svg .cf-span{fill:none;stroke-width:2.2}
.calc-card svg .cf-span.sp-short{stroke:var(--c-down)}.calc-card svg .cf-span.sp-surp{stroke:var(--c-up)}
.calc-card svg .cf-span-t{font:600 11px var(--sans);paint-order:stroke;stroke:var(--panel);stroke-width:3px}
.calc-card svg .cf-span-t.sp-short{fill:var(--c-down)}.calc-card svg .cf-span-t.sp-surp{fill:var(--c-up)}
.calc-why{background:var(--accent-soft);border-radius:8px;padding:8px 10px;font-size:13.5px;line-height:1.5;color:var(--ink)}

/* "!" note with pop-up */
.calc-warn{display:inline-flex;align-items:center;justify-content:center;width:15px;height:15px;margin-left:6px;border-radius:50%;background:#d98a1c;color:#fff;font:700 10px/1 system-ui,sans-serif;cursor:help;vertical-align:1px;position:relative;flex:none}
.calc-warn[hidden]{display:none}
.calc-warn:focus{outline:2px solid var(--accent,#1f6f5c);outline-offset:1px}
.calc-warn-pop{position:fixed;z-index:60;visibility:hidden;opacity:0;transition:opacity .12s;background:var(--ink,#1d2422);color:#fff;font:400 12.5px/1.45 system-ui,sans-serif;padding:8px 10px;border-radius:6px;box-shadow:0 6px 18px rgba(0,0,0,.18);text-align:left;white-space:normal;pointer-events:none;letter-spacing:0;text-transform:none}
.calc-warn:hover .calc-warn-pop,.calc-warn:focus .calc-warn-pop{visibility:visible;opacity:1}
/* Graph animations: Economics + Business & Management on one page (2026-09-28) */
.subject-block{margin-top:28px}
.subject-block + .subject-block{margin-top:52px;padding-top:28px;border-top:1px solid var(--line)}
.subject-title{font-size:30px;margin:0 0 4px}
.subject-sub{margin:4px 0 0}
.subject-block .gallery-cols{margin-top:18px}
.subject-block[hidden] + .subject-block{margin-top:28px;padding-top:0;border-top:0}
/* calculators: points on the D/S diagrams (hovering a number lights up its point) */
.calc-card svg .cf-pt{fill:var(--c-pt);stroke:var(--ink);stroke-width:1.2}
.calc-card svg .cf-old{opacity:.45}
.calc-card svg line.cf-old{stroke-dasharray:6 5}
/* balance of payments table (calculator) */
.bop-table{width:100%;max-width:560px}
.bop-table .bop-head td{font-weight:600;background:var(--chip);text-align:left}
.bop-table .bop-sub td:first-child{padding-left:22px}
.bop-table .bop-total td{border-top:1.5px solid var(--ink);font-weight:600}
.bop-table td.bop-calc{background:var(--accent-soft)}
.bop-table b[data-ref]{font-weight:inherit}
.calc-card svg circle.p-run{r:8}.calc-card svg .cf-pt.glow{r:5.5}