/* Layout: a fitting-room page. The calculator sits on a tape-measure card at the top; long-form guide below in one reading column with a sticky contents rail on wide screens. */
:root{
  --ground:#F4F3F7;      /* cool lilac-grey, like a fitting-room wall */
  --paper:#FFFFFF;
  --ink:#1D1A2B;         /* deep aubergine ink */
  --muted:#5D5871;
  --line:#DCD9E4;
  --tape:#F2C230;        /* tape-measure yellow: the one bold note */
  --tape-ink:#2A2208;
  --accent:#5B3FC4;      /* violet for links and the result */
  --accent-soft:#ECE8FB;
  --good:#1F7A4D; --warn:#A86200; --bad:#B42318;
  --f-display:"Young Serif", Georgia, "Times New Roman", serif;
  --f-body:"Figtree", system-ui, -apple-system, "Segoe UI", sans-serif;
  --f-mono:"IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;
}
@media (prefers-color-scheme: dark){ :root:not([data-theme="light"]){
  --ground:#14121C; --paper:#1D1A28; --ink:#ECE9F5; --muted:#A6A0BA; --line:#34304A;
  --tape:#E9B923; --tape-ink:#221B04; --accent:#A996FF; --accent-soft:#2A2442;
  --good:#5BC28B; --warn:#E3A33D; --bad:#F07D70; color-scheme:dark }}
:root[data-theme="dark"]{
  --ground:#14121C; --paper:#1D1A28; --ink:#ECE9F5; --muted:#A6A0BA; --line:#34304A;
  --tape:#E9B923; --tape-ink:#221B04; --accent:#A996FF; --accent-soft:#2A2442;
  --good:#5BC28B; --warn:#E3A33D; --bad:#F07D70; color-scheme:dark }

*{box-sizing:border-box}
body{background:var(--ground);color:var(--ink);font-family:var(--f-body);font-size:17px;line-height:1.65;margin:0}
a{color:var(--accent);text-underline-offset:3px}
a:focus-visible,button:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid var(--accent);outline-offset:2px;border-radius:6px}
h1,h2,h3{font-family:var(--f-display);font-weight:400;text-wrap:balance;line-height:1.15;margin:0}
h2{font-size:clamp(1.6rem,3.2vw,2.15rem);margin-bottom:.6rem}
h3{font-size:1.25rem;margin:1.6rem 0 .4rem}
p{margin:0 0 1rem}
.wrap{max-width:1180px;margin:0 auto;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
.mono{font-family:var(--f-mono);font-variant-numeric:tabular-nums}
.eyebrow{font-family:var(--f-mono);font-size:.78rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}

/* header */
.site-head{border-bottom:1px solid var(--line);background:var(--paper)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;padding-block:14px;flex-wrap:wrap}
.logo{display:flex;align-items:center;gap:10px;font-weight:700;color:var(--ink);text-decoration:none;font-size:1.02rem}
.logo-mark{width:30px;height:30px;border-radius:50%;background:var(--tape);display:grid;place-items:center;color:var(--tape-ink);font-family:var(--f-mono);font-size:.75rem;font-weight:500}
.nav{display:flex;gap:20px;flex-wrap:wrap;font-size:.95rem}
.nav a{color:var(--muted);text-decoration:none;font-weight:500}
.nav a:hover{color:var(--ink)}
.menu-btn{display:none;border:1px solid var(--line);background:var(--paper);color:var(--ink);border-radius:10px;width:42px;height:42px;cursor:pointer;align-items:center;justify-content:center;padding:0}
.menu-btn span,.menu-btn span::before,.menu-btn span::after{display:block;width:18px;height:2px;background:var(--ink);border-radius:2px;position:relative;transition:transform .2s ease,background .2s ease}
.menu-btn span::before,.menu-btn span::after{content:"";position:absolute;left:0}
.menu-btn span::before{top:-6px}
.menu-btn span::after{top:6px}
.menu-btn[aria-expanded="true"] span{background:transparent}
.menu-btn[aria-expanded="true"] span::before{transform:translateY(6px) rotate(45deg)}
.menu-btn[aria-expanded="true"] span::after{transform:translateY(-6px) rotate(-45deg)}
@media (max-width:720px){
  .site-head .wrap{flex-wrap:nowrap}
  .menu-btn{display:inline-flex}
  .site-head{position:relative}
  .nav{display:none;position:absolute;left:0;right:0;top:100%;z-index:20;flex-direction:column;gap:0;background:var(--paper);border-bottom:1px solid var(--line);padding:6px max(16px,env(safe-area-inset-right,0px)) 10px max(16px,env(safe-area-inset-left,0px));box-shadow:0 14px 24px -18px rgba(30,20,60,.4)}
  .nav.open{display:flex}
  .nav a{padding:12px 4px;border-bottom:1px solid var(--line);font-size:1rem;color:var(--ink)}
  .nav a:last-child{border-bottom:0}
}

/* hero */
.hero{padding-block:40px 28px}
.hero h1{font-size:clamp(1.75rem,6.4vw,2.5rem);white-space:nowrap}
.byline{display:flex;flex-wrap:wrap;align-items:center;gap:6px 14px;margin-top:12px;font-size:.9rem;color:var(--muted)}
.byline .avatar{width:28px;height:28px;border-radius:50%;background:var(--accent-soft);color:var(--accent);display:grid;place-items:center;font-weight:700;font-size:.8rem}
.byline strong{color:var(--ink);font-weight:600}
.byline .sep{width:4px;height:4px;border-radius:50%;background:var(--line)}
.hero .lede{font-size:1.12rem;color:var(--muted);max-width:62ch;margin-top:14px}
.hero .lede strong{color:var(--ink);font-weight:600}
.facts{display:flex;flex-wrap:wrap;gap:8px 18px;margin-top:16px;font-size:.92rem;color:var(--muted)}
.facts span::before{content:"";display:inline-block;width:7px;height:7px;border-radius:50%;background:var(--tape);margin-right:8px;vertical-align:middle}

/* calculator card */
.calc{background:var(--paper);border:1px solid var(--line);border-radius:18px;overflow:hidden;margin-bottom:56px;box-shadow:0 1px 0 var(--line),0 18px 40px -28px rgba(30,20,60,.35)}
.tape{height:34px;background:var(--tape);color:var(--tape-ink);position:relative;
  background-image:
   repeating-linear-gradient(90deg,var(--tape-ink) 0 1px,transparent 1px 100%),
   repeating-linear-gradient(90deg,var(--tape-ink) 0 1px,transparent 1px 100%);
  background-size:48px 14px,12px 7px;background-repeat:repeat-x;background-position:0 0,0 0}
.tape-nums{position:absolute;inset:auto 0 3px 0;display:flex;font-family:var(--f-mono);font-size:.68rem;padding-left:3px;overflow:hidden;white-space:nowrap}
.tape-nums span{width:48px;flex:none}
.calc-body{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(0,1fr);gap:0}
.calc-in{padding:26px;border-right:1px solid var(--line);min-width:0}
.calc-out{padding:26px;min-width:0;display:flex;flex-direction:column;gap:16px}
.seg{display:inline-flex;border:1px solid var(--line);border-radius:999px;padding:3px;background:var(--ground)}
.seg button{border:0;background:transparent;color:var(--muted);font:600 .92rem var(--f-body);padding:7px 16px;border-radius:999px;cursor:pointer}
.seg button[aria-pressed="true"]{background:var(--paper);color:var(--ink);box-shadow:0 1px 3px rgba(0,0,0,.12)}
.toggles{display:flex;flex-wrap:wrap;gap:12px;margin-bottom:20px}
.fields{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.field{min-width:0}
.field label{display:block;font-weight:600;font-size:.92rem;margin-bottom:4px}
.field .hint{display:block;font-size:.8rem;color:var(--muted);line-height:1.35;margin-top:4px}
.inbox{display:flex;align-items:center;border:1px solid var(--line);border-radius:10px;background:var(--ground);overflow:hidden}
.inbox input{flex:1;min-width:0;width:100%;border:0;background:transparent;color:var(--ink);font:500 1.1rem var(--f-mono);padding:10px 12px}
.inbox input:focus{outline:none}
.inbox:focus-within{border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
.inbox .u{font-family:var(--f-mono);font-size:.85rem;color:var(--muted);padding-right:12px}
.field.optional label::after{content:" optional";font-weight:400;color:var(--muted);font-size:.8rem}
.calc-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:20px;align-items:center}
.btn{border:0;border-radius:10px;font:600 1rem var(--f-body);padding:12px 20px;cursor:pointer}
.btn-primary{background:var(--ink);color:var(--paper)}
.btn-ghost{background:transparent;color:var(--ink);border:1px solid var(--line)}
.err{color:var(--bad);font-size:.9rem;margin-top:10px;min-height:1.2em}
.example-tag{font-size:.8rem;color:var(--muted)}

.result-top{display:flex;gap:18px;align-items:flex-start}
.fig{flex:none;width:132px;height:250px;background:var(--ground);border-radius:12px;display:grid;place-items:center}
.fig svg{width:100%;height:100%}
.res-name{font-family:var(--f-display);font-size:clamp(1.7rem,3vw,2.2rem);line-height:1.1}
.res-sub{color:var(--muted);font-size:.95rem;margin-top:6px}
.match{display:grid;gap:7px}
.match-row{display:grid;grid-template-columns:8.5em 1fr 3em;gap:10px;align-items:center;font-size:.9rem}
.bar{height:8px;border-radius:99px;background:var(--ground);overflow:hidden}
.bar i{display:block;height:100%;background:var(--accent);border-radius:99px;transition:width .4s ease}
.match-row:not(:first-child) .bar i{background:var(--muted);opacity:.55}
.ratios{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}
.ratio{border:1px solid var(--line);border-radius:10px;padding:9px 10px}
.ratio b{display:block;font:500 1.15rem var(--f-mono)}
.ratio span{font-size:.78rem;color:var(--muted);line-height:1.3;display:block}
.pill{display:inline-block;font-size:.72rem;font-weight:600;padding:2px 8px;border-radius:99px;margin-top:4px}
.pill.good{color:var(--good);background:color-mix(in srgb,var(--good) 14%,transparent)}
.pill.warn{color:var(--warn);background:color-mix(in srgb,var(--warn) 14%,transparent)}
.empty{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;gap:10px;border:2px dashed var(--line);border-radius:14px;padding:32px 20px;color:var(--muted);min-height:260px}
.empty b{font-family:var(--f-display);font-weight:400;font-size:1.4rem;color:var(--ink)}
#resWrap{display:flex;flex-direction:column;gap:16px}
.tips{background:var(--accent-soft);border-radius:12px;padding:14px 16px;font-size:.95rem}
.tips h3{margin:0 0 6px;font-size:1.05rem}
.tips ul{margin:0;padding-left:1.1rem}
.res-link{font-weight:600}
.copy-row{display:flex;gap:10px;align-items:center;flex-wrap:wrap;font-size:.88rem;color:var(--muted)}

/* article */
.page{display:grid;grid-template-columns:220px minmax(0,1fr);gap:56px;padding-bottom:64px}
.toc{position:sticky;top:20px;align-self:start;font-size:.9rem}
.toc ol{list-style:none;margin:10px 0 0;padding:0;display:grid;gap:7px;border-left:2px solid var(--line)}
.toc a{color:var(--muted);text-decoration:none;display:block;padding-left:12px;margin-left:-2px;border-left:2px solid transparent;line-height:1.35}
.toc a:hover{color:var(--ink);border-left-color:var(--tape)}
article{max-width:720px;min-width:0}
article section{padding-top:8px;margin-bottom:52px;scroll-margin-top:16px}
article ul,article ol{padding-left:1.25rem;margin:0 0 1rem}
article li{margin-bottom:.35rem}
.callout{border-left:4px solid var(--tape);background:var(--paper);padding:14px 18px;border-radius:0 10px 10px 0;margin:1.2rem 0}
.tbl{overflow-x:auto;margin:1rem 0 1.4rem;border:1px solid var(--line);border-radius:12px;background:var(--paper)}
table{border-collapse:collapse;width:100%;font-size:.93rem}
th,td{text-align:left;padding:10px 14px;border-bottom:1px solid var(--line);vertical-align:top}
th{font-weight:600;background:var(--ground)}
tr:last-child td{border-bottom:0}
td.mono,th.mono{white-space:nowrap}
.formula{font-family:var(--f-mono);background:var(--paper);border:1px dashed var(--line);border-radius:10px;padding:14px 16px;margin:0 0 1rem;font-size:1rem}

.shapes{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin:1.2rem 0}
.shape{background:var(--paper);border:1px solid var(--line);border-radius:14px;padding:14px;display:flex;flex-direction:column;gap:6px;text-decoration:none;color:var(--ink)}
.shape:hover{border-color:var(--accent)}
.shape svg{width:56px;height:96px;align-self:center}
.shape b{font-family:var(--f-display);font-weight:400;font-size:1.1rem}
.shape span{font-size:.86rem;color:var(--muted);line-height:1.45}
.shape .rule{font-family:var(--f-mono);font-size:.74rem;color:var(--muted)}

.steps{counter-reset:s;list-style:none;padding:0;display:grid;gap:12px}
.steps li{counter-increment:s;background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:14px 16px 14px 56px;position:relative}
.steps li::before{content:counter(s);position:absolute;left:16px;top:14px;width:26px;height:26px;border-radius:50%;background:var(--tape);color:var(--tape-ink);display:grid;place-items:center;font:500 .85rem var(--f-mono)}

.study{display:grid;gap:10px;margin:1rem 0 1.2rem;background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:16px}
.study-row{display:grid;grid-template-columns:7em 1fr 3.2em;gap:12px;align-items:center;font-size:.92rem}
.study-row .bar{height:12px}
.study-row:first-child .bar i{background:var(--tape)}
.study-row:not(:first-child) .bar i{background:var(--muted);opacity:.5}
.src{font-size:.8rem;color:var(--muted)}
.measure-fig{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:12px;margin:0 0 1.2rem}
.measure-fig svg{display:block;width:100%;height:auto;max-width:560px;margin:0 auto}
.example{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:18px 20px;margin:1.2rem 0}
.example h3{margin:0 0 10px}
.example ol{margin:0 0 12px;padding-left:1.25rem}
.example .ok{color:var(--good);font-weight:600}
.example .verdict{background:var(--accent-soft);border-radius:10px;padding:12px 14px;margin:0}

details{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:0 16px;margin-bottom:8px}
summary{cursor:pointer;font-weight:600;padding:14px 0;list-style:none;display:flex;justify-content:space-between;gap:12px}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";font-family:var(--f-mono);color:var(--muted)}
details[open] summary::after{content:"−"}
details p{padding-bottom:14px;margin:0}

.tools{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}
.tool{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:14px 16px;text-decoration:none;color:var(--ink)}
.tool:hover{border-color:var(--accent)}
.tool b{display:block}
.tool span{font-size:.86rem;color:var(--muted)}
.disclaimer{font-size:.85rem;color:var(--muted);border-top:1px solid var(--line);padding-top:16px}

footer{background:var(--paper);border-top:1px solid var(--line);font-size:.9rem;color:var(--muted)}
footer .wrap{padding-block:28px;display:flex;flex-wrap:wrap;gap:12px 28px;justify-content:space-between}
footer a{color:var(--muted)}

@media (max-width:980px){
  .page{grid-template-columns:1fr;gap:0}
  .toc{display:none}
}
@media (max-width:860px){
  .calc-body{grid-template-columns:1fr}
  .calc-in{border-right:0;border-bottom:1px solid var(--line)}
}
@media (max-width:560px){
  body{font-size:16px}
  .calc-in,.calc-out{padding:18px}
  .fields{grid-template-columns:1fr 1fr;gap:10px}
  .shapes{grid-template-columns:repeat(2,minmax(0,1fr))}
  .tools{grid-template-columns:1fr}
  .ratios{grid-template-columns:repeat(3,minmax(0,1fr))}
  .fig{width:104px;height:200px}
  .match-row{grid-template-columns:7.5em 1fr 2.8em}
}
@media (prefers-reduced-motion:reduce){ .bar i{transition:none} }

.shape-hero{display:grid;grid-template-columns:minmax(0,1fr) 180px;gap:32px;align-items:center}
.shape-hero-fig{width:180px;height:300px;background:var(--paper);border:1px solid var(--line);border-radius:16px;display:grid;place-items:center;padding:14px}
.shape-hero-fig svg{width:100%;height:100%}
.eyebrow a{color:inherit}
.fields.three{grid-template-columns:repeat(3,minmax(0,1fr))}
.res-name.is-yes{color:var(--good)}
.calc.mini #resWrap{display:flex;flex-direction:column;gap:14px}
.calc.mini .ratios{grid-template-columns:repeat(2,minmax(0,1fr))}
.celebs{list-style:none;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(170px,1fr));gap:10px}
.celebs li{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:12px 14px;margin:0}
.celebs strong{display:block}
.celebs span{font-size:.85rem;color:var(--muted)}
@media (max-width:720px){.shape-hero{grid-template-columns:1fr}.shape-hero-fig{display:none}.hero h1{white-space:normal}}
@media (max-width:480px){.fields.three{grid-template-columns:1fr 1fr}}
[hidden]{display:none!important}
/* site header + footer v2 */
.nav{align-items:center}
.nav details.dd{position:relative;background:none;border:0;border-radius:0;padding:0;margin:0}
.nav .dd summary{list-style:none;cursor:pointer;color:var(--muted);font-weight:500;padding:0;display:flex;align-items:center;gap:6px;justify-content:flex-start}
.nav .dd summary::-webkit-details-marker{display:none}
.nav .dd summary::after{content:"";font-family:inherit;width:6px;height:6px;border-right:1.5px solid currentColor;border-bottom:1.5px solid currentColor;transform:translateY(-2px) rotate(45deg);transition:transform .15s}
.nav .dd[open] summary::after{content:"";transform:translateY(1px) rotate(-135deg)}
.nav .dd summary:hover,.nav .dd[open] summary{color:var(--ink)}
.dd-panel{position:absolute;top:calc(100% + 14px);left:50%;transform:translateX(-50%);min-width:250px;background:var(--paper);border:1px solid var(--line);border-radius:14px;box-shadow:0 18px 40px -20px rgba(30,20,60,.35);padding:8px;z-index:40;display:grid;gap:1px}
.dd-2{grid-template-columns:1fr 1fr;min-width:460px;gap:0 12px}
.dd-2>div{display:grid;gap:1px;align-content:start}
.dd-end .dd-panel{left:auto;right:0;transform:none}
.nav .dd-panel a{display:block;padding:7px 10px;border-radius:8px;color:var(--ink);font-weight:500;font-size:.92rem;white-space:nowrap;border:0}
.nav .dd-panel a:hover{background:var(--accent-soft)}
.dd-h{display:block;font:500 .7rem var(--f-mono);letter-spacing:.08em;text-transform:uppercase;color:var(--muted);padding:6px 10px 4px}
.site-foot .foot-grid{display:grid;grid-template-columns:1.3fr repeat(5,minmax(0,1fr));gap:24px;padding-block:36px 20px;justify-content:initial}
.site-foot .fh{font:500 .72rem var(--f-mono);letter-spacing:.08em;text-transform:uppercase;color:var(--ink);margin:0 0 10px}
.site-foot .foot-grid a{display:block;padding:3px 0;text-decoration:none;color:var(--muted);font-size:.88rem}
.site-foot .foot-grid a:hover{color:var(--ink)}
.site-foot .foot-grid a.logo{display:flex;color:var(--ink);font-size:1rem;margin-bottom:10px;padding:0}
.site-foot .foot-brand p{margin:0;font-size:.88rem;max-width:30ch}
.site-foot .foot-bottom{display:flex;flex-wrap:wrap;justify-content:space-between;gap:8px 24px;border-top:1px solid var(--line);padding-block:16px 24px;font-size:.82rem}
@media (max-width:980px){.site-foot .foot-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.site-foot .foot-brand{grid-column:1/-1}}
@media (max-width:720px){
  .nav{align-items:stretch}
  .nav .dd summary{padding:12px 4px;border-bottom:1px solid var(--line);color:var(--ink);font-size:1rem;justify-content:space-between}
  .dd-panel,.dd-end .dd-panel{position:static;transform:none;min-width:0;box-shadow:none;border:0;border-radius:0;padding:4px 0 8px 12px;background:none}
  .dd-2{grid-template-columns:1fr;min-width:0}
  .nav .dd-panel a{white-space:normal;padding:9px 6px;font-size:.95rem}
  .nav{flex-wrap:nowrap;max-height:calc(100vh - 72px);overflow-y:auto}
}
@media (max-width:560px){.site-foot .foot-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}

/* logo v2 */
.logo-icon{flex:none;display:block;border-radius:8px}.logo-word{font-weight:700;letter-spacing:-.01em}.logo-word b{color:var(--accent);font-weight:700}

/* author link */
.byline a{color:inherit;text-decoration:none}.byline a:hover strong{text-decoration:underline;text-underline-offset:3px}