/* Owner-question pages: a case file, read top to bottom.
   Layout: one reading column with a sticky stage rail on wide screens; the rail folds into a contents strip on phones. */
:root{
  --bg:#F5F8FE;--sheet:#FFFFFF;--ink:#051E5B;--text:#1A1A1A;--muted:#4B5563;--line:#DCE6FB;--line-2:#C0D2F9;
  --accent:#1D4ED8;--accent-2:#2563EB;--accent-soft:rgba(37,99,235,.10);--warn:#8A5A00;--warn-soft:rgba(233,169,37,.16);
  --neg:#C2462B;--pos:#15803D;--panel:#051E5B;--panel-text:#E8EEF2;--panel-muted:#A9BCE8;
  --serif:"Montserrat",Georgia,"Times New Roman",serif;--sans:"Inter",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;--mono:"JetBrains Mono",ui-monospace,Consolas,monospace;
  --r:12px;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --bg:#0A1230;--sheet:#101B42;--ink:#F1F5F7;--text:#D6DEE5;--muted:#93A3B2;--line:#1F2D5C;--line-2:#2B3D75;
  --accent:#8DB4FF;--accent-2:#7FB0FF;--accent-soft:rgba(127,176,255,.10);--warn:#F2C46B;--warn-soft:rgba(233,169,37,.12);
  --neg:#FF8A70;--pos:#6EE7A0;--panel:#060D26;--panel-text:#E8EEF2;--panel-muted:#93A3B2;color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#0A1230;--sheet:#101B42;--ink:#F1F5F7;--text:#D6DEE5;--muted:#93A3B2;--line:#1F2D5C;--line-2:#2B3D75;
  --accent:#8DB4FF;--accent-2:#7FB0FF;--accent-soft:rgba(127,176,255,.10);--warn:#F2C46B;--warn-soft:rgba(233,169,37,.12);
  --neg:#FF8A70;--pos:#6EE7A0;--panel:#060D26;--panel-text:#E8EEF2;--panel-muted:#93A3B2;color-scheme:dark}

*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important;animation:none!important}}
body{margin:0;background:var(--bg);color:var(--text);font:17px/1.7 var(--sans);-webkit-font-smoothing:antialiased}
a{color:var(--accent);text-underline-offset:3px}
a:focus-visible,button:focus-visible,summary:focus-visible,input:focus-visible{outline:2px solid var(--accent-2);outline-offset:2px;border-radius:6px}
h1,h2,h3{font-family:var(--serif);color:var(--ink);font-weight:600;text-wrap:balance;line-height:1.2}
h2{font-size:clamp(1.55rem,1.2rem + 1.4vw,2.05rem);margin:0 0 .5em}
h3{font-size:1.15rem;margin:1.4em 0 .4em}
p{margin:0 0 1em}
strong,b{color:var(--ink)}
.num,.mono{font-family:var(--mono);font-variant-numeric:tabular-nums}

.q-wrap{max-width:1140px;margin:0 auto;padding-block:28px 64px;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
.q-mast{display:flex;flex-wrap:wrap;gap:6px 14px;align-items:center;font:500 .8rem var(--mono);letter-spacing:.04em;color:var(--muted);text-transform:uppercase}
.q-mast a{color:var(--muted);text-decoration:none}.q-mast a:hover{color:var(--accent)}
.q-mast .sep{opacity:.5}

/* opening */
.q-open{max-width:780px;margin:30px 0 8px}
.q-open h1{font-size:clamp(2rem,1.4rem + 3vw,3.2rem);margin:0 0 .35em;letter-spacing:-.01em}
.q-open h1 em{font-style:normal;color:var(--accent-2)}
.q-sub{font-size:1.15rem;color:var(--muted);max-width:640px}
.q-brief{background:var(--sheet);border:1px solid var(--line);border-radius:var(--r);padding:20px 22px;margin:24px 0}
.q-brief .lbl{display:block;font:600 .72rem var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--accent);margin-bottom:6px}
.q-brief p{margin:0;font-size:1.05rem;color:var(--ink)}
.q-leave{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:10px;margin:0;padding:0;list-style:none}
.q-leave li{border-top:2px solid var(--ink);padding-top:8px;font-size:.92rem;color:var(--muted)}
.q-leave li b{display:block;font:600 .74rem var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--ink)}

/* layout */
.q-body{display:grid;grid-template-columns:220px minmax(0,1fr);gap:56px;margin-top:40px}
.q-rail{position:sticky;top:calc(20px + env(safe-area-inset-top,0px));align-self:start;font-size:.88rem}
.q-rail b{display:block;font:600 .72rem var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--muted);margin-bottom:10px}
.q-rail ol{list-style:none;margin:0;padding:0;border-left:1px solid var(--line-2)}
.q-rail a{display:block;padding:6px 0 6px 14px;margin-left:-1px;border-left:2px solid transparent;color:var(--muted);text-decoration:none;line-height:1.35}
.q-rail a small{display:block;font:500 .68rem var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--accent);opacity:.85}
.q-rail a:hover,.q-rail a.on{color:var(--ink);border-left-color:var(--accent-2)}
.q-main{min-width:0;max-width:760px}
.q-sec{padding-top:12px;margin-bottom:56px;scroll-margin-top:16px}
.q-stage{display:inline-block;font:600 .72rem var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--accent);margin-bottom:8px}

/* devices */
.qs{display:grid;gap:10px;margin:18px 0}
.qs details{background:var(--sheet);border:1px solid var(--line);border-radius:var(--r)}
.qs summary{cursor:pointer;list-style:none;display:grid;grid-template-columns:30px minmax(0,1fr);gap:12px;padding:15px 16px;font-weight:600;color:var(--ink);line-height:1.5}
.qs summary::-webkit-details-marker{display:none}
.qs summary span{font:600 .8rem var(--mono);color:var(--accent);background:var(--accent-soft);border-radius:8px;height:30px;display:grid;place-items:center}
.qs summary:after{content:"Reveal";grid-column:2;font:500 .72rem var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--muted)}
.qs details[open] summary:after{content:none}
.qs details>div{padding:0 16px 14px 58px;color:var(--text)}
.note{border-left:3px solid var(--accent-2);padding:4px 0 4px 16px;margin:22px 0;color:var(--ink)}
.note.warn{border-left-color:#F2B33D}
.pull{font:500 1.35rem/1.45 var(--serif);color:var(--ink);margin:26px 0;max-width:680px}
.cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:12px;margin:16px 0}
.cell{background:var(--sheet);border:1px solid var(--line);border-radius:var(--r);padding:14px 16px;min-width:0}
.cell h3{margin:0 0 .3em;font-size:1.02rem}
.cell p{margin:0;font-size:.93rem;color:var(--muted)}
.tag{display:inline-block;font:600 .7rem var(--mono);letter-spacing:.06em;text-transform:uppercase;padding:2px 8px;border-radius:999px;background:var(--accent-soft);color:var(--accent);margin-bottom:6px}
.tag.w{background:var(--warn-soft);color:var(--warn)}
.tag.n{background:rgba(194,70,43,.12);color:var(--neg)}
ol.steps{list-style:none;counter-reset:s;margin:16px 0;padding:0;display:grid;gap:10px}
ol.steps>li{counter-increment:s;display:grid;grid-template-columns:38px minmax(0,1fr);gap:12px;align-items:start}
ol.steps>li:before{content:counter(s);font:600 .9rem var(--mono);color:var(--accent);border:1px solid var(--line-2);border-radius:50%;width:32px;height:32px;display:grid;place-items:center;background:var(--sheet)}
ol.steps>li p{margin:.15em 0 0;color:var(--muted)}
ul.tick{padding-left:1.1em}ul.tick li{margin-bottom:.45em}

/* equation */
.eq{display:flex;flex-wrap:wrap;gap:8px;align-items:stretch;margin:20px 0}
.eq>div{flex:1 1 130px;background:var(--sheet);border:1px solid var(--line);border-radius:10px;padding:10px 12px;font-weight:600;color:var(--ink);font-size:.95rem;min-width:0}
.eq>div small{display:block;font-weight:400;color:var(--muted);font-size:.78rem;line-height:1.4;margin-top:3px}
.eq>.lhs{flex:0 0 auto;background:var(--ink);color:var(--bg);display:grid;place-items:center}
.eq>.op{flex:0 0 auto;background:none;border:0;padding:10px 0;font:600 1.2rem var(--mono);color:var(--accent);display:grid;place-items:center}

/* tables */
.tw{overflow-x:auto;margin:14px 0;border:1px solid var(--line);border-radius:var(--r);background:var(--sheet)}
table{border-collapse:collapse;width:100%;font-size:.92rem}
th,td{padding:9px 12px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}
th{font:600 .72rem var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--muted);background:var(--bg)}
tr:last-child td{border-bottom:0}
td.num{text-align:right;white-space:nowrap}
tr.tot td{font-weight:700;color:var(--ink);border-top:2px solid var(--ink)}

/* tools */
.tool{border:1px solid var(--line);border-radius:14px;overflow:hidden;margin:20px 0;background:var(--sheet)}
.tool-h{display:flex;flex-wrap:wrap;justify-content:space-between;gap:4px 12px;padding:12px 16px;border-bottom:1px solid var(--line)}
.tool-h b{font-family:var(--serif);font-size:1.05rem;color:var(--ink)}
.tool-h span{font:500 .72rem var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--muted);align-self:center}
.tool-b{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr)}
.tool-in{padding:14px 16px;display:grid;gap:10px;align-content:start}
.fld label{display:flex;justify-content:space-between;gap:8px;font-size:.84rem;font-weight:600;color:var(--ink);margin-bottom:4px}
.fld output{font-family:var(--mono);color:var(--accent)}
.fld input[type=number]{width:100%;padding:9px 11px;border:1px solid var(--line-2);border-radius:9px;font:inherit;font-family:var(--mono);background:var(--bg);color:var(--ink)}
.fld input[type=range]{width:100%;accent-color:var(--accent-2)}
.tool-out{background:var(--panel);color:var(--panel-text);padding:18px;font-size:.92rem}
.tool-out .big span{display:block;font:500 .7rem var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--panel-muted)}
.tool-out .big b{display:block;font:600 1.9rem var(--serif);color:#fff;margin:2px 0}
.tool-out .big small{color:var(--panel-muted)}
.tool-out .big{margin-bottom:14px}
.tool-out ul{list-style:none;margin:0 0 12px;padding:0}
.tool-out li{display:flex;justify-content:space-between;gap:10px;padding:7px 0;border-bottom:1px dashed rgba(255,255,255,.14)}
.tool-out li b{font-family:var(--mono);color:#fff;white-space:nowrap}
.tool-out p{color:var(--panel-text)}
.tool-out .m{color:var(--panel-muted);font-size:.84rem}
.tool-out b.neg{color:#FF8A70}.tool-out b.pos{color:#3FE0C5}

/* casebook */
.cases{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:10px;margin:18px 0 0}
.case-btn{position:relative;text-align:left;font:inherit;cursor:pointer;background:var(--sheet);color:var(--text);border:1px solid var(--line);border-radius:var(--r);padding:14px 16px 16px;transition:border-color .15s,transform .15s,box-shadow .15s}
.case-btn .ind{display:block;font:600 .7rem var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--accent)}
.case-btn .who{display:block;font:600 1rem/1.35 var(--serif);color:var(--ink);margin:4px 0 6px}
.case-btn .peek{display:block;font-size:.86rem;line-height:1.5;color:var(--muted)}
.case-btn .go{display:block;margin-top:8px;font:600 .74rem var(--mono);letter-spacing:.04em;color:var(--accent)}
.case-btn[aria-expanded="true"]{border-color:var(--accent-2);box-shadow:0 0 0 1px var(--accent-2) inset}
.case-btn[aria-expanded="true"] .go:after{content:" (open)"}
@media (hover:hover){
  .case-btn .peek{max-height:0;opacity:0;overflow:hidden;transition:max-height .25s,opacity .2s}
  .case-btn:hover,.case-btn:focus-visible{border-color:var(--accent-2);transform:translateY(-2px);box-shadow:0 10px 24px rgba(5,30,91,.08)}
  .case-btn:hover .peek,.case-btn:focus-visible .peek,.case-btn[aria-expanded="true"] .peek{max-height:12em;opacity:1}
}
.case{border:1px solid var(--line-2);border-radius:14px;background:var(--sheet);margin:14px 0 0;padding:20px 20px 8px}
.case-top{display:flex;flex-wrap:wrap;justify-content:space-between;gap:8px;align-items:baseline}
.case-top h3{margin:0;font-size:1.3rem}
.case-close{font:600 .74rem var(--mono);background:none;border:1px solid var(--line-2);border-radius:999px;padding:4px 10px;color:var(--muted);cursor:pointer}
.case h4{font:600 .74rem var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--accent);margin:22px 0 6px}
.case .tw{margin-top:8px}
.case-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px}
.case-grid ul{padding-left:1.1em;margin:0}.case-grid li{margin-bottom:.4em;font-size:.93rem}
.case-hint{font-size:.85rem;color:var(--muted);margin-top:10px}

/* glossary + faq */
dl.gloss{display:grid;grid-template-columns:minmax(140px,190px) minmax(0,1fr);gap:0;margin:16px 0;border-top:1px solid var(--line)}
dl.gloss dt,dl.gloss dd{padding:10px 0;border-bottom:1px solid var(--line);margin:0}
dl.gloss dt{font-weight:700;color:var(--ink);padding-right:14px}
dl.gloss dd{color:var(--text);font-size:.95rem}
.faq details{border-bottom:1px solid var(--line)}
.faq summary{cursor:pointer;list-style:none;padding:14px 28px 14px 0;font-weight:600;color:var(--ink);position:relative}
.faq summary::-webkit-details-marker{display:none}
.faq summary:after{content:"+";position:absolute;right:4px;top:12px;font:500 1.2rem var(--mono);color:var(--accent)}
.faq details[open] summary:after{content:"−"}
.faq details>div{padding:0 0 14px;color:var(--text)}

/* close */
.q-close{border-top:2px solid var(--ink);padding-top:22px;margin-top:20px}
.q-close p{max-width:640px}
.q-close a.cta{display:inline-block;font-weight:600;text-decoration:none;color:var(--bg);background:var(--ink);padding:11px 18px;border-radius:999px}
.q-close a.cta:hover{background:var(--accent)}
.q-colo{margin-top:40px;font-size:.8rem;color:var(--muted)}

/* index */
.q-list{display:grid;gap:10px;margin:24px 0;max-width:780px}
.q-list a{display:block;background:var(--sheet);border:1px solid var(--line);border-radius:var(--r);padding:14px 16px;text-decoration:none;color:var(--text)}
.q-list a b{display:block;font-family:var(--serif);color:var(--ink);font-size:1.1rem}

/* contents strip on narrow screens */
.q-toc-m{display:none}
@media (max-width:900px){
  .q-body{grid-template-columns:minmax(0,1fr);gap:0;margin-top:24px}
  .q-rail{display:none}
  .q-toc-m{display:block;margin:20px 0 8px;background:var(--sheet);border:1px solid var(--line);border-radius:var(--r)}
  .q-toc-m summary{cursor:pointer;padding:12px 16px;font:600 .78rem var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--ink)}
  .q-toc-m ol{margin:0;padding:0 16px 12px 36px;font-size:.92rem}
  .q-toc-m li{padding:3px 0}
}
@media (max-width:640px){
  body{font-size:16px}
  .tool-b{grid-template-columns:minmax(0,1fr)}
  .eq>.op{display:none}.eq>div{flex-basis:100%}.eq>.lhs{flex-basis:100%;place-items:start}
  .qs details>div{padding-left:16px}
  dl.gloss{grid-template-columns:minmax(0,1fr)}dl.gloss dt{border-bottom:0;padding-bottom:0}
  .pull{font-size:1.15rem}
  .case{padding:16px 14px 6px}
}
@media (max-width:640px){
  table.stack thead{display:none}
  table.stack,table.stack tbody,table.stack tr,table.stack td{display:block;width:100%}
  table.stack tr{padding:12px 14px;border-bottom:1px solid var(--line)}
  table.stack tr:last-child{border-bottom:0}
  table.stack td{border:0;padding:3px 0}
  table.stack td:before{content:attr(data-label);display:block;font:600 .66rem var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
  table.stack td:first-child{font-weight:600;color:var(--ink)}
  table.stack td:first-child:before{display:none}
}

/* byline, doors, folds */
.q-by{font:500 .78rem var(--mono);letter-spacing:.04em;color:var(--muted);margin:-.2em 0 0}
.q-by a{color:var(--ink)}
.doors{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:10px;margin:8px 0 0}
.doors-k{grid-column:1/-1;font:600 .72rem var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.door{display:flex;flex-direction:column;gap:6px;background:var(--sheet);border:1px solid var(--line);border-left:3px solid var(--accent-2);border-radius:var(--r);padding:14px 16px;text-decoration:none;color:var(--text);transition:border-color .15s,transform .15s}
.door:hover{border-color:var(--accent-2);transform:translateY(-1px)}
.door-q{font:600 1.02rem/1.35 var(--serif);color:var(--ink)}
.door-a{font-size:.88rem;color:var(--muted);line-height:1.5}
.door:first-of-type{border-left-color:#F2B33D}
.q-fold>summary{list-style:none;cursor:pointer;display:block;border:1px solid var(--line);border-radius:var(--r);background:var(--sheet);padding:14px 16px;position:relative}
.q-fold>summary::-webkit-details-marker{display:none}
.q-fold>summary h2{margin:0;font-size:clamp(1.2rem,1rem + .8vw,1.5rem);padding-right:70px}
.q-fold-hint{position:absolute;right:16px;top:16px;font:600 .72rem var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--accent)}
.q-fold[open]>summary{border-color:transparent;background:none;padding-inline:0}
.q-fold[open] .q-fold-hint{display:none}
.q-fold>div{padding-top:4px}
details.sub{border:1px solid var(--line);border-radius:var(--r);background:var(--sheet);margin:12px 0}
details.sub>summary{cursor:pointer;padding:12px 16px;font-weight:600;color:var(--ink);list-style:none}
details.sub>summary::-webkit-details-marker{display:none}
details.sub>summary:before{content:"+ ";font-family:var(--mono);color:var(--accent)}
details.sub[open]>summary:before{content:"− "}
details.sub>div{padding:0 16px 12px}
.dl{display:flex;flex-wrap:wrap;gap:8px;margin:14px 0}
.dl a{font-weight:600;font-size:.9rem;text-decoration:none;border:1px solid var(--line-2);border-radius:999px;padding:8px 14px;color:var(--ink);background:var(--sheet)}
.dl a:hover{border-color:var(--accent-2)}

/* worksheet */
.ws-actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:14px}
.ws-btn{font:600 .9rem var(--sans);cursor:pointer;border:1px solid var(--ink);background:var(--ink);color:var(--bg);border-radius:999px;padding:9px 16px;text-decoration:none}
.ws-btn.ghost{background:none;color:var(--ink);border-color:var(--line-2)}
.ws-how{max-width:760px;margin:20px 0}
.ws-t td{height:34px;min-width:84px}
.ws-t td:first-child{min-width:260px;font-weight:600;color:var(--ink)}
.ws-t tr.calc td{background:var(--accent-soft)}
.ws-key{max-width:760px;font-size:.92rem;color:var(--muted)}
@media print{
  @page{size:A4 landscape;margin:12mm}
  body{background:#fff;color:#000;font-size:11px}
  .ws-actions,.q-mast{display:none}
  .q-wrap{padding:0;max-width:none}
  .tw{border:0;overflow:visible}
  table,th,td{border:1px solid #999!important}
  .ws-t td{height:26px}
}
.q-sec:has(> .q-fold){margin-bottom:14px;padding-top:0}
.wkbars{display:flex;align-items:flex-end;gap:3px;height:64px;margin:6px 0 2px}
.wkbars i{flex:1;background:#3FE0C5;border-radius:3px 3px 0 0;opacity:.75}
.wkbars i.n{background:#FF8A70}
.wkbars i.lo{opacity:1;outline:1px solid #fff}
.wkaxis{display:flex;justify-content:space-between;font:500 .68rem var(--mono);color:var(--panel-muted);margin-bottom:12px}
.fld.chk label{justify-content:flex-start;align-items:flex-start;gap:10px;font-weight:500;cursor:pointer}
.fld.chk input{width:18px;height:18px;margin-top:2px;accent-color:var(--accent-2);flex:0 0 auto}
.tool-out ul.roles li{display:block}
.q-rel .q-list{margin-top:10px}

/* diagrams */
.dg{margin:22px 0;padding:16px;background:var(--sheet);border:1px solid var(--line);border-radius:14px}
.dg svg{display:block;width:100%;height:auto;max-width:100%}
.dg figcaption{font-size:.86rem;color:var(--muted);margin-top:10px}
.dg-box{fill:var(--bg);stroke:var(--line-2);stroke-width:1}
.dg-hl{fill:var(--accent-soft);stroke:var(--accent-2)}
.dg-dark{fill:var(--ink)}
.dg-t{fill:var(--ink);font:600 15px var(--sans)}
.dg-sm{font-size:13px}
.dg-s{fill:var(--muted);font:500 12px var(--sans)}
.dg-tw{fill:var(--bg);font:600 17px var(--serif)}
.dg-sw{fill:var(--bg);opacity:.75;font:500 11px var(--sans)}
.dg-arrow{fill:none;stroke:var(--accent);stroke-width:1.6}
.dg-head{fill:var(--accent)}
.dg-axis{stroke:var(--ink);stroke-width:2}
.dg-dot{fill:var(--accent-2);stroke:var(--sheet);stroke-width:2}
.dg-span{stroke:var(--accent);stroke-width:2}
.dg-muted{stroke:var(--muted)}
.dg-key{stroke:var(--neg);stroke-width:3}
.dg-grid{stroke:var(--line);stroke-width:1}
.dg-fixed{stroke:var(--ink);stroke-width:2;stroke-dasharray:6 4}
.dg-gp{stroke:var(--accent);stroke-width:3}
.dg-loss{fill:var(--neg);opacity:.14}
.dg-profit{fill:var(--accent-2);opacity:.2}
.dg-neg{fill:var(--neg)}.dg-pos{fill:var(--pos)}
/* sources, notes */
.small-note{font-size:.9rem;color:var(--muted)}
ul.src{list-style:none;padding:0;margin:12px 0;display:grid;gap:8px}
ul.src li{background:var(--sheet);border:1px solid var(--line);border-radius:10px;padding:10px 14px;display:flex;flex-direction:column;gap:2px}
ul.src a{font-weight:600}
ul.src span{font-size:.86rem;color:var(--muted)}
.case-note{font-size:.86rem;color:var(--muted);border-left:3px solid var(--line-2);padding-left:12px;margin:10px 0 0}

/* ---------- Solve it in 3 minutes ---------- */
.solver{margin:26px 0 10px}
.sv{background:var(--sheet);border:1px solid var(--line);border-radius:22px;padding:20px 22px 24px;box-shadow:0 18px 50px rgba(5,30,91,.08);max-width:860px;min-height:380px}
.sv-top{display:flex;justify-content:space-between;align-items:center;gap:14px;margin-bottom:18px}
.sv-prog{flex:1;height:6px;border-radius:999px;background:var(--line);overflow:hidden;order:2}
.sv-prog i{display:block;height:100%;background:linear-gradient(90deg,var(--accent),var(--accent-2));border-radius:999px;transition:width .4s ease}
.sv-back{order:1;font:600 .8rem var(--mono);background:none;border:0;color:var(--muted);cursor:pointer;padding:4px 0}
.sv-back:hover{color:var(--ink)}
.sv-top>span{order:1;width:0}
.sv-screen{animation:svIn .35s ease}
@keyframes svIn{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}
.sv-k{display:inline-block;font:600 .72rem var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--accent);background:var(--accent-soft);padding:4px 10px;border-radius:999px}
.sv-q{font:600 clamp(1.3rem,1.05rem + 1.1vw,1.75rem)/1.3 var(--serif);color:var(--ink);margin:14px 0 10px;outline:none}
.sv-res{font-size:clamp(1.45rem,1.15rem + 1.3vw,2rem)}
.sv-lead{color:var(--muted);max-width:640px;margin:0 0 16px}
.sv-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-top:6px}
.sv-list{display:grid;gap:10px;margin-top:8px;max-width:620px}
.sv-opt{font:600 1rem/1.35 var(--sans);text-align:left;cursor:pointer;background:var(--bg);color:var(--ink);border:1.5px solid var(--line-2);border-radius:14px;padding:14px 16px;transition:border-color .15s,transform .15s,background .15s}
.sv-opt:hover:not([disabled]){border-color:var(--accent-2);transform:translateY(-1px)}
.sv-opt:active:not([disabled]){transform:scale(.99)}
.sv-opt.sel{border-color:var(--accent-2);background:var(--accent-soft)}
.sv-opt.ok{border-color:var(--pos);background:var(--accent-soft)}
.sv-opt.ok:after{content:"  ✓";color:var(--pos)}
.sv-opt.no{border-color:var(--neg);background:rgba(194,70,43,.08)}
.sv-opt.no:after{content:"  ✕";color:var(--neg)}
.sv-opt.dim{opacity:.55}
.sv-opt[disabled]{cursor:default}
.sv-ind b{display:block;font:600 1.02rem var(--serif)}
.sv-ind small{display:block;font:400 .82rem/1.4 var(--sans);color:var(--muted);margin-top:4px}
.sv-fb{margin:14px 0;padding:12px 14px;border-radius:12px;max-width:620px;animation:svIn .3s ease}
.sv-fb.ok{background:var(--accent-soft);border-left:4px solid var(--pos)}
.sv-fb.no{background:var(--warn-soft);border-left:4px solid #F2B33D}
.sv-next,.sv-ghost{display:inline-flex;align-items:center;font:600 .95rem var(--sans);cursor:pointer;border-radius:999px;padding:11px 18px;text-decoration:none;margin-top:6px}
.sv-next{background:var(--ink);color:var(--bg);border:1.5px solid var(--ink)}
.sv-next:hover{background:var(--accent);border-color:var(--accent)}
.sv-ghost{background:none;color:var(--ink);border:1.5px solid var(--line-2)}
.sv-ghost:hover{border-color:var(--accent-2)}
.sv-score{display:flex;align-items:baseline;gap:8px;margin:16px 0 0}
.sv-score b{font:600 4rem/1 var(--serif);color:var(--accent)}
.sv-score span{font:600 1.1rem var(--mono);color:var(--muted)}
.sv-urgent{margin:18px 0 0;font-size:.92rem;color:var(--muted)}
.sv-where{margin:18px 0;max-width:620px}
.sv-where>b,.sv-plan>b{display:block;font:600 .74rem var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin-bottom:8px}
.sv-bars{list-style:none;margin:0;padding:0;display:grid;gap:8px}
.sv-bars li{display:grid;grid-template-columns:100px minmax(0,1fr);gap:10px;align-items:center;font-size:.9rem;color:var(--muted)}
.sv-bars i{display:block;height:12px;background:var(--line);border-radius:999px;overflow:hidden}
.sv-bars em{display:block;height:100%;width:0;background:var(--accent);opacity:.35;border-radius:999px;transition:width .8s cubic-bezier(.2,.7,.2,1)}
.sv-bars li.top{color:var(--ink);font-weight:700}
.sv-bars li.top em{background:linear-gradient(90deg,var(--accent),var(--accent-2));opacity:1}
.sv-also{font-size:.92rem;color:var(--text);max-width:640px}
.sv-plan{background:var(--bg);border:1px solid var(--line);border-radius:16px;padding:16px 18px;margin:16px 0;max-width:680px}
.sv-plan ol{margin:0;padding-left:1.3em;display:grid;gap:8px}
.sv-plan li{font-weight:500;color:var(--ink)}
.sv-links{display:flex;flex-wrap:wrap;gap:6px 18px;margin:14px 0 0;font-weight:600;font-size:.92rem}
.sv-peek{font-size:.92rem;color:var(--muted);max-width:660px}
.sv-actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:8px}
.sv-note{font-size:.78rem;color:var(--muted);margin:14px 0 0}
.sv-copytext{width:100%;margin-top:10px;font:400 .85rem var(--mono);padding:10px;border-radius:10px;border:1px solid var(--line-2);background:var(--bg);color:var(--ink)}
.guide-intro{border-top:2px solid var(--ink);margin-top:40px;padding-top:22px;max-width:780px}
.guide-intro h2{margin:6px 0 6px}
@media (max-width:760px){.sv-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:480px){.sv{padding:16px 14px 20px;border-radius:18px}.sv-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.sv-ind small{display:none}.sv-ind{padding:12px}.sv-ind b{font-size:.95rem}.solver{margin-top:16px}.sv-bars li{grid-template-columns:82px minmax(0,1fr)}.sv-actions>*{flex:1 1 100%;justify-content:center}}
@media print{html.print-plan body *{visibility:hidden}html.print-plan .sv,html.print-plan .sv *{visibility:visible}html.print-plan .sv{position:absolute;left:0;top:0;box-shadow:none;border:0}html.print-plan .sv-actions,html.print-plan .sv-top{display:none}}

/* ---------- summary snippet ---------- */
.snip{display:grid;gap:10px;margin:18px 0 0;max-width:780px}
.snip-row{display:grid;grid-template-columns:120px minmax(0,1fr);gap:14px;align-items:start;background:var(--sheet);border:1px solid var(--line);border-radius:14px;padding:12px 16px}
.snip-row p{margin:0;color:var(--ink);font-weight:500}
.snip-k{font:600 .72rem var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--neg);padding-top:3px}
.snip-k.ok{color:var(--pos)}
@media (max-width:520px){.snip-row{grid-template-columns:minmax(0,1fr);gap:4px}}

/* ---------- solution ladder ---------- */
.lad{margin:30px 0 8px;max-width:860px}
.lad-head h2{margin:6px 0 4px}
.lad-hint{color:var(--muted);font-size:.9rem;margin:0 0 14px;display:flex;flex-wrap:wrap;gap:6px 14px;align-items:center}
.lad-hint .tp{display:none}
@media (hover:none){.lad-hint .hv{display:none}.lad-hint .tp{display:inline}}
.lad-prog{font:600 .74rem var(--mono);letter-spacing:.04em;color:var(--accent);background:var(--accent-soft);padding:3px 10px;border-radius:999px}
.lad-body{position:relative;padding-left:78px}
.lad-rail{position:absolute;left:0;top:0;bottom:0;width:64px}
.th-ladder .lad-rail{background:repeating-linear-gradient(to bottom,transparent 0 30px,var(--line-2) 30px 33px) 14px 0/36px 100% no-repeat}
.th-ladder .lad-rail:before,.th-ladder .lad-rail:after{content:"";position:absolute;top:0;bottom:0;width:4px;border-radius:4px;background:var(--line-2)}
.th-ladder .lad-rail:before{left:12px}.th-ladder .lad-rail:after{left:48px}
.lad-fig{position:absolute;left:8px;top:0;width:48px;height:72px;z-index:2;transition:transform .7s cubic-bezier(.3,.8,.3,1)}
.lad-fig svg{width:48px;height:72px;overflow:visible}
.fig-l{fill:none;stroke:var(--ink);stroke-width:3.2;stroke-linecap:round;stroke-linejoin:round}
.fig-head{fill:var(--ink)}
.fig-qm{fill:var(--accent);font:700 17px var(--serif)}
.fig-star path{fill:#F2B33D}
.lad-fig .pose,.lad-fig .fig-q,.lad-fig .fig-star{display:none}
.lad-fig.pose-puzzled .pose-puzzled,.lad-fig.pose-puzzled .fig-q{display:inline}
.lad-fig.pose-climb .pose-climb{display:inline}
.lad-fig.pose-win .pose-win,.lad-fig.pose-win .fig-star{display:inline}
.lad-fig.pose-puzzled .fig-q{animation:qbob 1.6s ease-in-out infinite;transform-origin:36px 10px}
.lad-fig.pose-puzzled svg{animation:sway 3s ease-in-out infinite;transform-origin:24px 70px}
.lad-fig.pose-climb svg{animation:climb .6s ease}
.lad-fig.pose-win svg{animation:jump .9s ease 2}
@keyframes qbob{0%,100%{transform:translateY(0) rotate(0)}50%{transform:translateY(-3px) rotate(10deg)}}
@keyframes sway{0%,100%{transform:rotate(0)}50%{transform:rotate(-3deg)}}
@keyframes climb{0%{transform:translateY(6px)}60%{transform:translateY(-4px)}100%{transform:none}}
@keyframes jump{0%,100%{transform:none}40%{transform:translateY(-10px)}}
.lad-rungs{list-style:none;margin:0;padding:0;display:flex;flex-direction:column-reverse;gap:8px}
.rung{background:var(--sheet);border:1.5px solid var(--line);border-radius:14px;transition:border-color .2s,box-shadow .25s,transform .2s;position:relative}
.rung-btn{width:100%;display:grid;grid-template-columns:34px minmax(0,1fr) 24px;gap:12px;align-items:center;text-align:left;background:none;border:0;padding:12px 14px;cursor:pointer;font:inherit;color:var(--text)}
.rn{width:34px;height:34px;border-radius:50%;display:grid;place-items:center;font:600 .9rem var(--mono);color:var(--accent);background:var(--accent-soft);transition:background .2s,color .2s}
.rt b{display:block;font:600 1.02rem/1.3 var(--serif);color:var(--ink)}
.rt small{display:block;color:var(--muted);font-size:.86rem;line-height:1.4;margin-top:2px}
.rc{font:600 1.2rem var(--mono);color:var(--accent);text-align:center;transition:transform .2s}
@media (hover:hover){
  .rt small{max-height:0;opacity:0;overflow:hidden;transition:max-height .25s,opacity .2s}
  .rung.lit .rt small,.rung.open .rt small{max-height:6em;opacity:1}
}
.rung.lit{border-color:var(--accent-2);box-shadow:0 0 0 4px var(--accent-soft),0 10px 26px rgba(37,99,235,.16);transform:translateX(3px)}
.rung.lit .rn,.rung.open .rn{background:var(--accent-2);color:var(--ink)}
.rung.seen .rn{background:var(--accent);color:#fff}
.rung.open{border-color:var(--accent-2)}
.rung.open .rc{transform:rotate(45deg)}
.rung-body{padding:0 16px 14px 60px;animation:svIn .3s ease}
.rung-body p{margin:.2em 0 .6em}
.rung-today{background:var(--accent-soft);border-radius:10px;padding:8px 12px;color:var(--ink)}
.rung-link{font-weight:600;font-size:.92rem}
.rung.here{border-color:#F2B33D;box-shadow:0 0 0 4px var(--warn-soft)}
.rung.here:after{content:"You are here";position:absolute;top:-10px;right:14px;font:600 .66rem var(--mono);letter-spacing:.08em;text-transform:uppercase;background:#F2B33D;color:#051E5B;padding:3px 8px;border-radius:999px}
.lad-goal,.lad-start{font:600 .8rem var(--mono);letter-spacing:.04em;padding:10px 14px;border-radius:12px;margin:8px 0;border:1.5px dashed var(--line-2);color:var(--muted)}
.lad-goal span{color:#F2B33D;margin-right:8px}
.lad-done .lad-goal{border-style:solid;border-color:#F2B33D;color:var(--ink);background:var(--warn-soft)}
.lad-start{color:var(--neg);border-color:rgba(194,70,43,.35)}
.lad-urgent{font-size:.92rem;color:var(--muted);margin:12px 0 0}
.sv-intro{max-width:780px;margin:30px 0 12px}
.sv-intro h2{margin:0 0 4px}
.sv-intro p{color:var(--muted);margin:0}
@media (max-width:520px){.lad-body{padding-left:62px}.lad-rail{width:52px}.th-ladder .lad-rail{background-position:10px 0;background-size:30px 100%}.th-ladder .lad-rail:before{left:8px}.th-ladder .lad-rail:after{left:40px}.lad-fig{left:2px}.rung-body{padding-left:16px}.rung-btn{gap:10px;padding:11px 12px}}
@media (prefers-reduced-motion:reduce){.lad-fig,.lad-fig svg,.lad-fig .fig-q{transition:none!important;animation:none!important}}

/* ---------- journey themes ---------- */
.lad-fig .tick{display:none}
.lad-fig.pose-win .tick{display:inline}
.fig-pack{fill:var(--accent)}
/* summit: a dotted trail up to a peak */
.th-summit .lad-rail:before{content:"";position:absolute;left:31px;top:34px;bottom:0;border-left:3px dotted var(--line-2)}
.th-summit .lad-rail:after{content:"";position:absolute;left:4px;top:0;width:56px;height:40px;background:linear-gradient(to bottom,#fff 0 22%,var(--line-2) 22%);clip-path:polygon(50% 0,100% 100%,0 100%);opacity:.9}
/* road: asphalt with a dashed centre line; headlights come on as you drive */
.th-road .lad-rail:before{content:"";position:absolute;left:8px;top:0;bottom:0;width:48px;border-radius:10px;background:#3A4652}
.th-road .lad-rail:after{content:"";position:absolute;left:31px;top:6px;bottom:6px;width:3px;background:repeating-linear-gradient(to bottom,#F6F4EF 0 12px,transparent 12px 24px);opacity:.7}
.car-body{fill:var(--accent-2)}.car-glass{fill:#0B2A73;opacity:.75}.car-wheel{fill:#051E5B}.car-light{fill:#8A96A3}
.beam path{fill:#F2B33D;opacity:0;transition:opacity .4s}
.lad-fig.pose-climb .car-light,.lad-fig.pose-win .car-light{fill:#F2D16B}
.lad-fig.pose-climb .beam path,.lad-fig.pose-win .beam path{opacity:.28}
.th-road .lad-fig.pose-climb svg,.th-pipe .lad-fig.pose-climb svg{animation:drive .6s ease}
@keyframes drive{0%{transform:translateY(8px)}100%{transform:none}}
/* pipe: a tube with gates the invoice flows through */
.th-pipe .lad-rail:before{content:"";position:absolute;left:20px;top:0;bottom:0;width:24px;border-radius:12px;background:var(--accent-soft);border:2px solid var(--line-2)}
.th-pipe .lad-rail:after{content:"";position:absolute;left:14px;top:20px;bottom:20px;width:36px;background:repeating-linear-gradient(to bottom,var(--line-2) 0 4px,transparent 4px 64px)}
.env-body{fill:var(--sheet);stroke:var(--accent);stroke-width:2.5}.env-flap{fill:none;stroke:var(--accent);stroke-width:2.5;stroke-linejoin:round}
.tick circle{fill:var(--pos)}.tick path{fill:none;stroke:#fff;stroke-width:2.5;stroke-linecap:round;stroke-linejoin:round}
/* tank: water level rises as you explore */
.tank{position:absolute;left:8px;top:0;bottom:0;width:48px;border:3px solid var(--line-2);border-radius:14px;overflow:hidden;background:var(--sheet)}
.tank .lvl{position:absolute;left:0;right:0;bottom:0;height:calc(var(--lvl,0) * 100%);background:linear-gradient(to top,var(--accent),var(--accent-2));transition:height .9s cubic-bezier(.3,.8,.3,1)}
.tank .lvl i{position:absolute;left:-50%;top:-8px;width:200%;height:16px;border-radius:40%;background:var(--accent-2);opacity:.6;animation:wave 3s linear infinite}
@keyframes wave{from{transform:translateX(0)}to{transform:translateX(25%)}}
.tank-lbl{position:absolute;top:8px;left:0;right:0;text-align:center;font:600 .7rem var(--mono);color:var(--ink);z-index:1}
/* thermometer: the reading climbs from red towards green */
.thermo{position:absolute;left:18px;top:0;bottom:0;width:28px}
.thermo .tube{position:absolute;left:6px;top:0;bottom:22px;width:16px;border:3px solid var(--line-2);border-radius:10px;overflow:hidden;background:var(--sheet);
  background-image:repeating-linear-gradient(to bottom,transparent 0 22px,var(--line) 22px 24px)}
.thermo .lvl{position:absolute;left:0;right:0;bottom:0;height:calc(var(--lvl,0) * 100%);background:var(--neg);transition:height .9s cubic-bezier(.3,.8,.3,1),background .6s}
.thermo .bulb{position:absolute;left:0;bottom:0;width:28px;height:28px;border-radius:50%;background:var(--neg);border:3px solid var(--line-2);transition:background .6s}
.th-thermo.lad-done .thermo .lvl,.th-thermo.lad-done .thermo .bulb{background:var(--pos)}
.th-tank.lad-done .tank{border-color:var(--accent-2);box-shadow:0 0 0 4px var(--accent-soft)}
@media (max-width:520px){.tank{left:4px;width:42px}.thermo{left:12px}.th-road .lad-rail:before{left:4px;width:44px}.th-road .lad-rail:after{left:25px}.th-pipe .lad-rail:before{left:14px}.th-pipe .lad-rail:after{left:8px}.th-summit .lad-rail:before{left:25px}}
@media (prefers-reduced-motion:reduce){.tank .lvl i{animation:none}.tank .lvl,.thermo .lvl{transition:none}}

/* phone gutters: comfortable, equal margins on both sides */
@media (max-width:640px){.q-wrap{padding-left:max(22px,env(safe-area-inset-left,0px));padding-right:max(22px,env(safe-area-inset-right,0px))}}