:root{
  --ink:#101C34; --ink-soft:#3D4C68; --paper:#E8ECF3; --card:#FBFCFE;
  --violet:#4B34E8; --gain:#0C7B55; --loss:#C42B3F; --rule:#C9D2E1; --tape:#FFFDF5;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);
  font-family:"IBM Plex Sans",system-ui,sans-serif;font-size:17px;line-height:1.65;
  -webkit-font-smoothing:antialiased}
.wrap{max-width:1080px;margin:0 auto;padding:0 22px}
h1,h2,h3{font-family:"Bricolage Grotesque","IBM Plex Sans",sans-serif;line-height:1.05;
  letter-spacing:-.02em;margin:0}
a{color:var(--violet)}

.masthead{border-bottom:1px solid var(--rule);background:var(--card)}
.masthead .wrap{display:flex;align-items:center;justify-content:space-between;min-height:66px;gap:16px}
.brand{font-family:"Bricolage Grotesque",sans-serif;font-weight:800;font-size:22px;
  letter-spacing:-.03em;text-decoration:none;color:var(--ink);flex-shrink:0}
.brand span{color:var(--violet)}
.masthead nav{display:flex;flex-wrap:wrap;gap:4px 18px;justify-content:flex-end}
.masthead nav a{font-size:13.5px;text-decoration:none;color:var(--ink-soft)}
.masthead nav a:hover,.masthead nav a[aria-current]{color:var(--violet)}

.crumbs{font-family:"IBM Plex Mono",monospace;font-size:12px;color:var(--ink-soft);
  padding:16px 0 0}
.crumbs a{color:var(--ink-soft);text-decoration:none}
.crumbs a:hover{color:var(--violet)}

.hero{padding:38px 0 18px}
.eyebrow{font-family:"IBM Plex Mono",monospace;font-size:12px;letter-spacing:.16em;
  text-transform:uppercase;color:var(--violet);margin:0 0 14px}
h1{font-size:clamp(32px,5.6vw,54px);font-weight:800;max-width:17ch}
.sub{color:var(--ink-soft);max-width:58ch;margin:16px 0 0;font-size:18px}

.calc{display:grid;grid-template-columns:1fr 380px;gap:26px;margin:30px 0 56px;align-items:start}
.panel{background:var(--card);border:1px solid var(--rule);border-radius:4px;padding:26px}
.legend{font-family:"IBM Plex Mono",monospace;font-size:11px;letter-spacing:.14em;
  text-transform:uppercase;color:var(--ink-soft);padding:0;margin:0 0 18px}
fieldset{border:0;padding:0;margin:0 0 22px}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:14px}
label{display:block;font-size:13px;font-weight:500;margin-bottom:6px}
.field{position:relative}
.field .unit{position:absolute;right:12px;top:50%;transform:translateY(-50%);
  font-family:"IBM Plex Mono",monospace;font-size:12px;color:var(--ink-soft);pointer-events:none}
input[type=number],select{width:100%;padding:12px 46px 12px 13px;border:1px solid var(--rule);
  border-radius:3px;background:#fff;font-family:"IBM Plex Mono",monospace;font-size:16px;color:var(--ink)}
select{padding-right:13px;appearance:none;background-image:linear-gradient(45deg,transparent 50%,var(--ink-soft) 50%),linear-gradient(135deg,var(--ink-soft) 50%,transparent 50%);
  background-position:calc(100% - 18px) 20px,calc(100% - 13px) 20px;background-size:5px 5px;background-repeat:no-repeat}
input:focus,select:focus{outline:2px solid var(--violet);outline-offset:1px;border-color:var(--violet)}
input::-webkit-outer-spin-button,input::-webkit-inner-spin-button{-webkit-appearance:none;margin:0}
input[type=number]{-moz-appearance:textfield}
.actions{display:flex;gap:10px;flex-wrap:wrap}
button{font-family:"IBM Plex Sans",sans-serif;font-size:15px;font-weight:600;
  padding:12px 22px;border-radius:3px;cursor:pointer;border:1px solid var(--ink)}
.btn-go{background:var(--ink);color:#fff}
.btn-go:hover{background:var(--violet);border-color:var(--violet)}
.btn-reset{background:transparent;color:var(--ink-soft);border-color:var(--rule)}
.btn-reset:hover{color:var(--ink);border-color:var(--ink)}
button:focus-visible{outline:2px solid var(--violet);outline-offset:2px}

.tape{background:var(--tape);border:1px solid var(--rule);border-radius:2px;
  padding:26px 24px 30px;font-family:"IBM Plex Mono",monospace;
  box-shadow:0 1px 0 var(--rule);position:sticky;top:20px}
.tape::after{content:"";display:block;height:12px;margin:22px -24px -30px;
  background:radial-gradient(circle at 6px -3px, transparent 7px, var(--tape) 7.5px) repeat-x;
  background-size:14px 14px}
.tape-head{display:flex;justify-content:space-between;font-size:11px;letter-spacing:.12em;
  text-transform:uppercase;color:var(--ink-soft);border-bottom:1px dashed var(--rule);padding-bottom:10px}
.result{padding:22px 0 16px;border-bottom:1px dashed var(--rule)}
.result-label{font-size:11px;letter-spacing:.12em;text-transform:uppercase;color:var(--ink-soft);margin:0}
.result-value{font-family:"Bricolage Grotesque",sans-serif;font-size:clamp(28px,4.6vw,40px);
  font-weight:800;letter-spacing:-.03em;line-height:1.1;margin:4px 0 0;transition:color .2s}
.result-roi{font-size:14px;margin:2px 0 0;color:var(--ink-soft)}
.gain{color:var(--gain)} .loss{color:var(--loss)} .neutral{color:var(--ink)}
.rows{margin:14px 0 0}
.row{display:flex;justify-content:space-between;gap:12px;font-size:13.5px;padding:7px 0;
  border-bottom:1px dotted var(--rule)}
.row:last-child{border-bottom:0}
.row dt{color:var(--ink-soft);margin:0}
.row dd{margin:0;font-variant-numeric:tabular-nums;font-weight:500;text-align:right}
.note{font-family:"IBM Plex Sans",sans-serif;font-size:12.5px;color:var(--ink-soft);
  margin:16px 0 0;line-height:1.5}

article{max-width:70ch;padding-bottom:20px}
article h2{font-size:clamp(24px,3.4vw,32px);font-weight:700;margin:48px 0 14px}
article h3{font-size:20px;font-weight:700;margin:30px 0 8px}
article p{margin:0 0 16px}
article ul,article ol{margin:0 0 16px;padding-left:20px}
article li{margin-bottom:7px}
.formula{background:var(--card);border-left:3px solid var(--violet);padding:18px 20px;
  font-family:"IBM Plex Mono",monospace;font-size:14.5px;line-height:1.9;margin:0 0 20px;overflow-x:auto}
.worked{background:var(--card);border:1px solid var(--rule);border-radius:4px;padding:22px 24px;margin:0 0 20px}
.worked p:last-child{margin-bottom:0}
table{width:100%;border-collapse:collapse;font-size:14.5px;margin:0 0 20px}
th,td{text-align:left;padding:10px 12px;border-bottom:1px solid var(--rule)}
thead th{font-family:"IBM Plex Mono",monospace;font-size:11px;letter-spacing:.1em;
  text-transform:uppercase;color:var(--ink-soft)}
tbody th{font-weight:500}
td:last-child{text-align:right;font-family:"IBM Plex Mono",monospace}
details{border-bottom:1px solid var(--rule);padding:16px 0}
summary{cursor:pointer;font-weight:600;font-size:17px;list-style:none}
summary::-webkit-details-marker{display:none}
summary::before{content:"+";color:var(--violet);font-family:"IBM Plex Mono",monospace;
  margin-right:10px;font-weight:600}
details[open] summary::before{content:"\2013"}
details p{margin:12px 0 0;color:var(--ink-soft)}
summary:focus-visible{outline:2px solid var(--violet);outline-offset:3px}

.grouphead{font-family:"Bricolage Grotesque",sans-serif;font-size:15px;font-weight:700;
  letter-spacing:.02em;text-transform:none;color:var(--ink-soft);margin:30px 0 12px;
  padding-bottom:8px;border-bottom:1px solid var(--rule)}
.grouphead:first-child{margin-top:0}
.related{border-top:1px solid var(--rule);margin-top:46px;padding-top:34px}
.related h2{font-family:"Bricolage Grotesque",sans-serif;font-size:22px;font-weight:700;margin:0 0 18px}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(238px,1fr));gap:14px;margin-bottom:20px}
.card{display:block;background:var(--card);border:1px solid var(--rule);border-radius:4px;
  padding:20px;text-decoration:none;color:var(--ink);transition:border-color .15s,transform .15s}
.card:hover{border-color:var(--violet);transform:translateY(-2px)}
.card .k{font-family:"IBM Plex Mono",monospace;font-size:10.5px;letter-spacing:.14em;
  text-transform:uppercase;color:var(--violet);display:block;margin-bottom:8px}
.card h3{font-size:17.5px;font-weight:700;margin:0 0 6px}
.card p{font-size:13.5px;color:var(--ink-soft);margin:0;line-height:1.5}

footer{border-top:1px solid var(--rule);background:var(--card);margin-top:30px;padding:34px 0}
footer .wrap{display:flex;flex-wrap:wrap;gap:14px;justify-content:space-between;
  font-size:13.5px;color:var(--ink-soft)}
footer a{color:var(--ink-soft)}

@media (max-width:860px){
  .calc{grid-template-columns:1fr}
  .tape{position:static}
  .masthead .wrap{flex-direction:column;align-items:flex-start;padding-top:12px;padding-bottom:12px}
  .masthead nav{justify-content:flex-start}
  .hero{padding:26px 0 12px}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}