/* Home page: board animation + long-form explainer */
.home{background:var(--bg)}
.home header{position:sticky;top:0;z-index:10;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.home header .in{display:flex;justify-content:space-between;align-items:center;max-width:1120px;margin:0 auto;padding:14px 24px}
.home nav.toc{display:flex;gap:22px;font:500 11.5px/1 var(--mono);letter-spacing:.08em;text-transform:uppercase}
.home nav.toc a{color:var(--muted);text-decoration:none}.home nav.toc a:hover{color:var(--fg)}
@media(max-width:820px){.home nav.toc{display:none}}

.wrap{max-width:1120px;margin:0 auto;padding:0 24px}
.narrow{max-width:720px;margin:0 auto}

.hero2{padding-top:64px;padding-bottom:28px;text-align:center}
.hero2 .eyebrow{font:500 11.5px/1 var(--mono);letter-spacing:.18em;text-transform:uppercase;color:var(--muted)}
.hero2 h1{font-size:clamp(44px,8vw,92px);font-weight:500;letter-spacing:-.02em;margin:18px auto 14px;max-width:900px;line-height:.98}
.hero2 h1 em{font-style:italic;font-weight:400}
.hero2 p.lede{font:400 clamp(19px,2.3vw,23px)/1.5 var(--serif);color:var(--muted);max-width:640px;margin:0 auto}

/* board */
.board{margin:36px auto 0;max-width:980px}
.board .frame{border:1px solid var(--fg);padding:10px;background:var(--bg)}
.board canvas{display:block;width:100%;height:auto;aspect-ratio:12/7}
.board .under{display:grid;grid-template-columns:1fr auto;gap:18px;align-items:center;margin-top:16px}
@media(max-width:700px){.board .under{grid-template-columns:1fr}}
.board .cap .k{font:500 11px/1 var(--mono);letter-spacing:.14em;text-transform:uppercase;color:var(--muted)}
.board .cap .t{font:500 26px/1.15 var(--serif);margin-top:6px}
.board .cap .d{font-size:14.5px;color:var(--muted);margin-top:4px;max-width:560px}
.mini{display:grid;justify-content:start;width:max-content;grid-template-columns:auto 58px 58px;grid-template-rows:22px 42px 42px;font:500 10.5px/1 var(--mono);text-transform:uppercase;letter-spacing:.06em}
.mini span{display:flex;align-items:center;justify-content:center;color:var(--muted);white-space:nowrap}
.mini span:nth-child(4),.mini span:nth-child(7){justify-content:flex-end}
.mini .c{display:flex;align-items:center;justify-content:center;margin:-1px 0 0 -1px;border:1px solid var(--line);font:500 14px var(--mono);color:var(--fg);text-transform:none;transition:background .3s,color .3s}
.mini .c.on{background:var(--fg);color:var(--bg);border-color:var(--fg)}
.controls{display:flex;gap:6px;flex-wrap:wrap;margin-top:14px;justify-content:center}
.controls button{background:none;border:1px solid var(--line);padding:7px 12px;font:500 11px/1 var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--muted);cursor:pointer;border-radius:var(--r)}
.controls button.on{border-color:var(--fg);color:var(--fg)}
.controls button:hover{color:var(--fg)}

/* article */
.article{padding:40px 0 20px}
.sec{padding:56px 0;border-top:1px solid var(--line)}
.sec:first-child{border-top:0}
.sec .num{font:500 11px/1 var(--mono);letter-spacing:.16em;text-transform:uppercase;color:var(--muted)}
.sec h2{font-size:clamp(32px,4.4vw,48px);margin:12px 0 18px;font-weight:500}
.sec h3{font-size:24px;margin:28px 0 8px;font-weight:500}
.sec p,.sec li{font:400 19.5px/1.62 var(--serif);color:var(--fg)}
.sec p+p{margin-top:14px}
.sec p.muted{color:var(--muted)}
.sec ul,.sec ol{padding-left:22px;margin:12px 0}
.sec li+li{margin-top:6px}
var,.v{font-style:italic;font-family:var(--serif)}
.mathline{font:400 22px/1.5 var(--serif);text-align:center;margin:20px 0;padding:14px;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.mathline .note{display:block;font:400 13px/1.4 var(--sans);color:var(--muted);margin-top:4px}
blockquote{margin:22px 0;padding:4px 0 4px 22px;border-left:2px solid var(--fg);font:italic 400 21px/1.55 var(--serif);color:var(--muted)}
blockquote cite{display:block;font:500 11px/1 var(--mono);letter-spacing:.1em;text-transform:uppercase;font-style:normal;margin-top:10px}
.box{border:1px solid var(--fg);padding:22px 24px;margin:26px 0;background:var(--panel)}
.box .k{font:500 11px/1 var(--mono);letter-spacing:.16em;text-transform:uppercase}
.box p,.box li{font-size:18.5px}
.box.proof{border-color:var(--line)}
.qed{float:right;font:500 13px var(--mono)}
.qed::after{content:"";display:inline-block;width:10px;height:10px;background:var(--fg);margin-left:8px;vertical-align:-1px}
.side-note{font:400 15px/1.55 var(--sans)!important;color:var(--muted)!important}

/* payoff matrix as a board */
.matrix{display:grid;grid-template-columns:120px 1fr 1fr;grid-template-rows:auto auto 1fr 1fr;max-width:560px;margin:26px auto}
.matrix .corner{grid-row:1/3}
.matrix .colhead{grid-column:2/4;text-align:center;font:500 11px/1 var(--mono);letter-spacing:.12em;text-transform:uppercase;color:var(--muted);padding-bottom:8px}
.matrix .ch{text-align:center;font:500 13px/1 var(--mono);padding:8px 0;letter-spacing:.06em;text-transform:uppercase}
.matrix .rh{display:flex;align-items:center;justify-content:flex-end;padding-right:14px;font:500 13px/1.2 var(--mono);text-transform:uppercase;letter-spacing:.06em;text-align:right}
.matrix .rh small{display:block;color:var(--muted);font-size:10px;letter-spacing:.12em}
.matrix .cell{aspect-ratio:1.35;border:1px solid var(--fg);margin:-1px 0 0 -1px;position:relative;display:grid;place-items:center;transition:background .25s}
.matrix .cell.dark{background:var(--sq)}
.matrix .cell .pay{font:500 30px/1 var(--serif)}
.matrix .cell .pay b{font-weight:600}
.matrix .cell .pay .a{color:var(--fg)} .matrix .cell .pay .b{color:var(--muted)}
.matrix .cell .lab{position:absolute;left:8px;top:7px;font:500 10px/1 var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.matrix .cell .ne{position:absolute;right:8px;top:7px;font:500 10px/1 var(--mono);letter-spacing:.08em;text-transform:uppercase;background:var(--fg);color:var(--bg);padding:3px 5px}
.matrix .cell .arrows{position:absolute;inset:0;pointer-events:none}
.legend{display:flex;gap:18px;justify-content:center;font:13px var(--sans);color:var(--muted);flex-wrap:wrap}
.legend i{display:inline-block;width:10px;height:10px;margin-right:6px;vertical-align:-1px}

/* tables */
.tbl{width:100%;border-collapse:collapse;margin:20px 0;font:15.5px/1.45 var(--sans)}
.tbl th{font:500 11px/1.3 var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--muted);text-align:left;padding:10px 12px;border-bottom:1px solid var(--fg);background:none}
.tbl td{padding:12px;border-top:1px solid var(--line);vertical-align:top}
.tbl td.y{font-weight:600}
.tbl tr:first-child td{border-top:0}

/* charts */
.figure{margin:28px 0}
.figure svg{width:100%;height:auto;display:block;overflow:visible}
.figure .figcap{font:400 14px/1.5 var(--sans);color:var(--muted);margin-top:10px}
.figure .figcap b{color:var(--fg);font-weight:600}
.slider{display:grid;grid-template-columns:140px 1fr 64px;gap:14px;align-items:center;margin:10px 0;font:500 12px/1 var(--mono);letter-spacing:.04em}
.slider input{padding:0;border:0;background:none;accent-color:var(--fg)}
.slider output{text-align:right;font:500 15px var(--mono)}
.readout{display:flex;gap:10px;flex-wrap:wrap;margin-top:12px}
.readout .r{border:1px solid var(--line);padding:10px 12px;font:13px var(--sans);color:var(--muted);flex:1;min-width:150px}
.readout .r b{display:block;font:500 22px/1.2 var(--serif);color:var(--fg);margin-top:2px}
.warn{font:14px var(--sans);color:var(--err);margin-top:8px;min-height:1.2em}
.tool{border:1px solid var(--line);padding:18px 20px;margin:24px 0;background:var(--panel)}
.tool .k{font:500 11px/1 var(--mono);letter-spacing:.16em;text-transform:uppercase;margin-bottom:10px}

/* closing: the group */
.group{padding:72px 0;border-top:1px solid var(--fg)}
.group h2{font-size:clamp(34px,5vw,56px);font-weight:500}
.levers{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:0;border:1px solid var(--fg);margin:24px 0}
.levers>div{padding:20px;border-right:1px solid var(--line);border-bottom:1px solid var(--line)}
.levers .k{font:500 11px/1 var(--mono);letter-spacing:.14em;text-transform:uppercase;color:var(--muted)}
.levers h4{font:500 22px/1.2 var(--serif);margin:10px 0 6px}
.levers p{font:15px/1.55 var(--sans)!important;color:var(--muted)!important}
.home .stats{margin-top:20px}
.home .stat{border-radius:var(--r);border-color:var(--line)}
.home footer{border-top:1px solid var(--line);padding:28px 0 56px;font-size:13px;color:var(--faint)}
@media(max-width:600px){
  .sec p,.sec li{font-size:18px}
  .matrix{grid-template-columns:78px 1fr 1fr}
  .matrix .cell .pay{font-size:24px}
  .slider{grid-template-columns:1fr 54px}.slider label{grid-column:1/-1;margin:0}
}

/* ---------- landing (single screen) ---------- */
.landing{min-height:100vh;display:flex;flex-direction:column}
.land{flex:1;max-width:1240px;width:100%;margin:0 auto;padding:clamp(18px,3vh,40px) 24px 24px;display:flex;flex-direction:column;justify-content:center;gap:clamp(18px,3.2vh,36px)}
.lgrid{display:grid;grid-template-columns:minmax(0,.85fr) minmax(0,1.15fr);gap:clamp(28px,4vw,56px);align-items:center}
@media(max-width:920px){.lgrid{grid-template-columns:1fr}}
.ltext .eyebrow{font:500 11.5px/1 var(--mono);letter-spacing:.18em;text-transform:uppercase;color:var(--muted)}
.ltext h1{font-size:clamp(48px,5vw,78px);font-weight:500;letter-spacing:-.02em;line-height:.95;margin:14px 0 18px;white-space:nowrap}
.ltext h1 em{font-style:italic;font-weight:400}
.ltext .syn{font:400 clamp(21px,2.1vw,26px)/1.4 var(--serif);color:var(--fg);max-width:520px}
.ltext .syn2{font:400 15.5px/1.6 var(--sans);color:var(--muted);max-width:500px;margin-top:14px}
.landing .board{margin:0;max-width:none}
.landing .board .cap .t{font-size:22px}
.landing .board .cap .d{font-size:13.5px}
@media(min-width:921px){.landing .board .cap .d{display:none}.landing .board .under{margin-top:10px}.landing .controls{margin-top:10px}}
.landing .controls{justify-content:flex-start}
.strip .striphead{display:flex;justify-content:space-between;align-items:baseline;font:500 11px/1 var(--mono);letter-spacing:.14em;text-transform:uppercase;color:var(--muted);margin-bottom:6px}
.strip .striphead a{color:var(--fg);text-decoration:none}

/* ---------- folders ---------- */
.folders{display:grid;grid-template-columns:repeat(auto-fill,minmax(210px,1fr));gap:26px 16px;margin-top:28px}
.folder{position:relative;display:flex;flex-direction:column;gap:6px;border:1px solid var(--fg);background:var(--panel);padding:18px 16px 16px;margin-top:12px;text-decoration:none;color:var(--fg);transition:transform .15s ease,background .15s ease;min-height:150px}
.folder::before{content:"";position:absolute;left:-1px;top:-13px;width:46%;height:13px;border:1px solid var(--fg);border-bottom:0;background:var(--panel);border-radius:3px 6px 0 0;transition:background .15s ease}
.folder:hover{transform:translateY(-3px);background:var(--sunk)}
.folder:hover::before{background:var(--sunk)}
.folder .fn{font:500 11px/1 var(--mono);letter-spacing:.12em;color:var(--muted)}
.folder .ft{font:500 22px/1.15 var(--serif)}
.folder .fk{font:500 10.5px/1 var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--accent)}
.folder .fb{font:13.5px/1.5 var(--sans);color:var(--muted);margin-top:4px}
.mini-folders{grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:16px 10px;margin-top:12px}
.mini-folders .folder{min-height:0;padding:10px 12px;gap:3px;margin-top:10px}
.mini-folders .folder::before{top:-10px;height:10px}
.mini-folders .folder .ft{font-size:17px}
.mini-folders .folder .fb,.mini-folders .folder .fk{display:none}

/* ---------- folder pages ---------- */
.learnpage main{padding-bottom:40px}
.crumb{font:500 11px/1 var(--mono);letter-spacing:.12em;text-transform:uppercase;color:var(--muted);padding-top:40px}
.crumb a{color:var(--fg);text-decoration:none}
.sec.solo{border-top:0;padding-top:18px}
.learn-h1{font-size:clamp(40px,6vw,68px);font-weight:500;margin:14px 0 14px;letter-spacing:-.015em}
.learn-lede{font:400 21px/1.5 var(--serif);color:var(--muted);max-width:680px}
.tool.compact{padding:12px 16px;margin:0 0 22px}
.tool.compact .slider{margin:6px 0}
.pager{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:12px 0 24px;border-top:1px solid var(--line);padding-top:24px}
.pager a{display:block;border:1px solid var(--line);padding:14px 16px;text-decoration:none;color:var(--fg);font:500 19px/1.2 var(--serif)}
.pager a:hover{border-color:var(--fg)}
.pager a span{display:block;font:500 10.5px/1 var(--mono);letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin-bottom:8px}
.pager a.nx{text-align:right}
.group-solo h2{font-size:clamp(34px,5vw,52px)}
.home nav.toc a.on{color:var(--fg)}

/* ===================== oak & forest theme ===================== */
.home{background:var(--bg)}
.home header{background:color-mix(in srgb,var(--bg) 90%,transparent)}
.brand svg{color:var(--forest)}
/* wooden board */
.board .frame{border:10px solid var(--oak-dark);padding:0;background:var(--sq2);box-shadow:inset 0 0 0 1px rgba(0,0,0,.15),0 14px 30px -18px rgba(60,40,20,.55);border-radius:2px}
.mini .c.on{background:var(--forest);color:var(--panel);border-color:var(--forest)}
.controls button.on{border-color:var(--forest);color:var(--forest)}
/* chapters */
.chapters{grid-template-columns:repeat(auto-fit,minmax(240px,1fr))}
.chapters .folder{min-height:0}
.chapters .folder .fn{color:var(--oak);letter-spacing:.14em;text-transform:uppercase}
.folder{border-color:var(--forest)}
.folder::before{border-color:var(--forest)}
.folder.alt{background:var(--sunk)}
.folder.alt::before{background:var(--sunk)}
.land-chapters{grid-template-columns:repeat(3,1fr);gap:18px 16px;margin-top:12px}
.land-chapters .folder{padding:14px 16px;margin-top:10px}
.land-chapters .folder::before{top:-11px;height:11px}
.land-chapters .folder .ft{font-size:21px}
.land-chapters .folder .fb{font-size:13px;line-height:1.45}
@media(max-width:820px){.land-chapters{grid-template-columns:1fr}}
.chapter .sec:first-child{border-top:1px solid var(--line)}
.chapter .sec .num{color:var(--oak)}
.learnpage .tool.compact{display:grid;grid-template-columns:repeat(3,1fr) auto;gap:6px 18px;align-items:end;margin-top:18px}
.learnpage .tool.compact .k{grid-column:1/-1;margin-bottom:2px}
.learnpage .tool.compact .slider{grid-template-columns:1fr 34px;gap:4px 8px;margin:0}
.learnpage .tool.compact .slider label{grid-column:1/-1;margin:0;font-size:11px}
.learnpage .tool.compact .row{grid-column:auto;justify-content:flex-end}
.learnpage .tool.compact .warn{grid-column:1/-1;order:9;min-height:0}
@media(max-width:700px){.learnpage .tool.compact{grid-template-columns:1fr}}
.home nav.toc{gap:18px}
.home nav.toc a.on{color:var(--forest);text-decoration:underline;text-underline-offset:6px}
/* treeline */
.treeline{display:block;width:100%;height:110px}
.landtrees{height:clamp(56px,9vh,96px);margin-top:auto}
.landing .land{padding-bottom:8px}
.forestfoot{border-top:0!important;padding:0!important;margin-top:40px}
.forestfoot .fbar{background:var(--forest);color:#d9dccb;font-size:13px;padding:20px 0 36px}
.box{background:var(--panel);border-color:var(--forest)}
.matrix .cell{border-color:var(--forest)}
blockquote{border-left-color:var(--oak)}
.qed::after{background:var(--forest)}
.levers{border-color:var(--forest)}
.group{border-top-color:var(--forest)}

/* ---------- cleaner mini payoff table ---------- */
.mini{display:grid;grid-template-columns:auto 64px 64px;grid-template-rows:auto 46px 46px auto;column-gap:0;width:max-content;justify-content:start;font:500 10.5px/1 var(--mono);letter-spacing:.08em;text-transform:uppercase}
.mini span{display:block;color:var(--muted);white-space:nowrap}
.mini .mh{text-align:center;padding:0 0 8px}
.mini .mr{display:flex!important;align-items:center;justify-content:flex-end!important;padding-right:14px}
.mini .c{display:flex;align-items:center;justify-content:center;gap:1px;margin:-1px 0 0 -1px;border:1px solid var(--line);background:var(--panel);font:500 22px/1 var(--serif);letter-spacing:0;text-transform:none;color:var(--fg);transition:background .35s,color .35s,border-color .35s}
.mini .c i{font-style:normal;color:var(--faint);margin-right:4px}
.mini .c.on{background:var(--forest);border-color:var(--forest);color:var(--panel)}
.mini .c.on i{color:rgba(250,247,239,.6)}
.mini .mnote{grid-column:2/4;text-align:center;padding-top:8px;font-size:9.5px;color:var(--faint)}
/* ---------- treeline: whole trees, scaled not cropped ---------- */
.treeline{display:block;width:100%;height:auto}
.landtrees{height:auto;margin-top:auto}

/* ---------- cleaner mini payoff table ---------- */
.mini{display:grid;grid-template-columns:auto 64px 64px;grid-template-rows:auto 46px 46px auto;column-gap:0;width:max-content;justify-content:start;font:500 10.5px/1 var(--mono);letter-spacing:.08em;text-transform:uppercase}
.mini span{display:block;color:var(--muted);white-space:nowrap}
.mini .mh{text-align:center;padding:0 0 8px}
.mini .mr{display:flex!important;align-items:center;justify-content:flex-end!important;padding-right:14px}
.mini .c{display:flex;align-items:center;justify-content:center;gap:1px;margin:-1px 0 0 -1px;border:1px solid var(--line);background:var(--panel);font:500 22px/1 var(--serif);letter-spacing:0;text-transform:none;color:var(--fg);transition:background .35s,color .35s,border-color .35s}
.mini .c i{font-style:normal;color:var(--faint);margin-right:4px}
.mini .c.on{background:var(--forest);border-color:var(--forest);color:var(--panel)}
.mini .c.on i{color:rgba(250,247,239,.6)}
.mini .mnote{grid-column:2/4;text-align:center;padding-top:8px;font-size:9.5px;color:var(--faint)}
/* ---------- treeline: whole trees, scaled not cropped ---------- */
.treeline{display:block;width:100%;height:auto}
.landtrees{height:auto;margin-top:auto}
/* mini table v2: axis labels instead of crowded prefixes */
.mini{grid-template-columns:auto auto 66px 66px;grid-template-rows:auto auto 46px 46px auto}
.mini .ax-b{grid-column:3/5;grid-row:1;text-align:center;padding-bottom:6px;color:var(--oak);letter-spacing:.14em}
.mini .mh{grid-row:2;padding-bottom:7px}
.mini .h1{grid-column:3}.mini .h2{grid-column:4}
.mini .ax-a{grid-column:1;grid-row:3/5;writing-mode:vertical-rl;transform:rotate(180deg);display:flex!important;align-items:center;justify-content:center;padding-left:8px;color:var(--oak);letter-spacing:.14em}
.mini .mr{grid-column:2;padding-right:10px}
.mini .r1{grid-row:3}.mini .r2{grid-row:4}
.mini .c[data-k="ss"]{grid-column:3;grid-row:3}.mini .c[data-k="sh"]{grid-column:4;grid-row:3}
.mini .c[data-k="hs"]{grid-column:3;grid-row:4}.mini .c[data-k="hh"]{grid-column:4;grid-row:4}
.mini .mnote{grid-column:3/5;grid-row:5}
/* treeline must not be squeezed by the flex layout */
.landtrees{flex:none;width:100%;aspect-ratio:1440/96;height:auto}
.landing .land{gap:clamp(14px,2.6vh,30px);padding-top:clamp(14px,2.4vh,32px)}
@media(min-width:921px){.landing .board{max-width:570px;width:100%;justify-self:end}}
.landing .controls{flex-wrap:nowrap;gap:5px}
.landing .controls button{padding:6px 9px;font-size:10px;letter-spacing:.05em}
.landing .board .under{gap:12px}
.landing .land{padding-bottom:0}
.ltext .syn{font-size:clamp(24px,2.4vw,30px)}
.ltext .syn2{font-size:16px}
.land-chapters .folder .fb{font-size:14px}
.ltext .syn{font-size:clamp(24px,2.4vw,30px)}
.ltext .syn2{font-size:16px}
.land-chapters .folder .fb{font-size:14px}