:root {
  --paper: #f5f2ea;
  --panel: #fffdf8;
  --ink: #17212b;
  --muted: #5d6670;
  --rule: #d6d0c1;
  --rule-strong: #17212b;
  --accent: #b84a12;
  --ok: #1f6b3a;
  --bad: #a5271c;
  --sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Consolas, monospace;
}

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 16px/1.55 var(--sans);
}

a { color: inherit; text-decoration-color: var(--accent); text-underline-offset: 3px; }
a:hover { color: var(--accent); }

.wrap { max-width: 1040px; margin: 0 auto; padding: 0 24px; }

/* Header */
.bar { border-bottom: 2px solid var(--rule-strong); background: var(--paper); }
.bar .wrap { display: flex; align-items: center; justify-content: space-between; gap: 24px; height: 56px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; font-family: var(--mono); font-weight: 600; letter-spacing: .08em; font-size: 14px; text-transform: uppercase; }
.brand i { display: inline-block; width: 14px; height: 14px; background: var(--ink); box-shadow: 5px 5px 0 var(--accent); margin-right: 5px; }
.bar nav { display: flex; gap: 22px; font-size: 14px; }
.bar nav a { text-decoration: none; padding: 4px 0; border-bottom: 2px solid transparent; }
.bar nav a:hover, .bar nav a[aria-current] { border-bottom-color: var(--accent); color: var(--ink); }

/* Type */
h1, h2, h3 { font-weight: 600; line-height: 1.15; margin: 0 0 .5em; letter-spacing: -.01em; }
h1 { font-size: clamp(28px, 4.2vw, 42px); max-width: 20ch; }
h2 { font-size: 22px; }
h3 { font-size: 16px; }
p { margin: 0 0 1em; }
.lead { font-size: 18px; max-width: 58ch; color: #2c3742; }
.eyebrow { font-family: var(--mono); font-size: 12px; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); margin-bottom: 14px; }
.muted { color: var(--muted); }
.small { font-size: 13px; }

main { padding: 44px 0 72px; }
.section { margin-top: 56px; padding-top: 28px; border-top: 1px solid var(--rule); }

/* Buttons and forms */
.btn { display: inline-block; font: 600 15px var(--sans); padding: 11px 20px; border: 2px solid var(--ink); background: var(--ink); color: #fff; cursor: pointer; text-decoration: none; border-radius: 2px; }
.btn:hover { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.ghost { background: transparent; color: var(--ink); }
.btn.ghost:hover { background: var(--ink); border-color: var(--ink); color: #fff; }

label, .label { display: block; font-family: var(--mono); font-size: 12px; letter-spacing: .06em; text-transform: uppercase; color: var(--muted); margin-bottom: 5px; }
input, select { width: 100%; font: 16px var(--sans); color: var(--ink); background: var(--panel); border: 1px solid #9a9486; border-radius: 2px; padding: 9px 10px; min-height: 42px; }
input:focus, select:focus, .btn:focus-visible, a:focus-visible { outline: 3px solid #e8a672; outline-offset: 1px; }
.hint { font-size: 12.5px; color: var(--muted); margin-top: 4px; }
.err { color: var(--bad); font-size: 13px; margin-top: 4px; display: block; }

.grid { display: grid; gap: 18px 20px; grid-template-columns: repeat(6, 1fr); }
.c2 { grid-column: span 2; } .c3 { grid-column: span 3; } .c6 { grid-column: span 6; }
@media (max-width: 720px) { .c2, .c3 { grid-column: span 6; } }

/* Calculator layout */
.tool { display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); gap: 36px; align-items: start; margin-top: 28px; }
@media (max-width: 860px) { .tool { grid-template-columns: 1fr; } }
.sheet { background: var(--panel); border: 1px solid var(--rule-strong); padding: 24px; }
.sheet legend { font-family: var(--mono); font-size: 12px; letter-spacing: .1em; text-transform: uppercase; padding: 0 8px; margin-left: -8px; background: var(--panel); }
fieldset { border: 0; padding: 0; margin: 0 0 22px; }
.sheet .rule { border: 0; border-top: 1px dashed var(--rule); margin: 4px 0 22px; }

.result { border: 2px solid var(--rule-strong); background: var(--panel); position: sticky; top: 16px; }
.result header { display: flex; justify-content: space-between; padding: 8px 16px; background: var(--ink); color: #fff; font-family: var(--mono); font-size: 12px; letter-spacing: .1em; text-transform: uppercase; }
.result .body { padding: 20px 16px 16px; }
.result .empty { color: var(--muted); }
.rate { font: 600 54px/1 var(--mono); letter-spacing: -.03em; }
.rate small { font-size: 24px; }
.status { display: inline-block; margin: 12px 0 6px; padding: 3px 9px; font: 600 12px var(--mono); letter-spacing: .08em; text-transform: uppercase; border: 2px solid currentColor; }
.status.bad { color: var(--bad); } .status.ok { color: var(--ok); } .status.na { color: var(--muted); }
dl.kv { display: grid; grid-template-columns: auto 1fr; gap: 6px 16px; margin: 16px 0 0; font-size: 14px; border-top: 1px solid var(--rule); padding-top: 14px; }
dl.kv dt { color: var(--muted); } dl.kv dd { margin: 0; text-align: right; font-family: var(--mono); }
.result .actions { display: flex; gap: 10px; margin-top: 18px; }

/* Tables */
table { width: 100%; border-collapse: collapse; font-size: 15px; background: var(--panel); border: 1px solid var(--rule-strong); }
th, td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--rule); }
th { font-family: var(--mono); font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); background: #ece7da; }
td.num, th.num { text-align: right; font-family: var(--mono); }
tr:last-child td { border-bottom: 0; }

.formula { font-family: var(--mono); font-size: 14px; background: var(--panel); border-left: 4px solid var(--accent); padding: 10px 14px; margin: 0 0 12px; overflow-x: auto; }

.two { display: grid; grid-template-columns: 1fr 1fr; gap: 36px; }
@media (max-width: 760px) { .two { grid-template-columns: 1fr; } }

.signup { border: 1px solid var(--rule-strong); background: var(--panel); padding: 20px; }
.signup form { display: flex; gap: 10px; flex-wrap: wrap; }
.signup input[type=email] { flex: 1 1 220px; width: auto; }

.notice { border-left: 4px solid var(--accent); background: var(--panel); padding: 12px 16px; font-size: 14px; }

footer { border-top: 2px solid var(--rule-strong); padding: 26px 0 40px; font-size: 13px; color: var(--muted); }
footer .wrap { display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; }

.sr { position: absolute; left: -9999px; }

/* Print: only the record */
.print-only { display: none; }
@media print {
  body { background: #fff; }
  .bar, footer, .sheet, .signup, .section, .actions, .eyebrow, h1, .lead, .no-print { display: none !important; }
  .tool { display: block; margin: 0; }
  .result { position: static; border: 1px solid #000; }
  .result header { background: #fff; color: #000; border-bottom: 1px solid #000; }
  .print-only { display: block; }
  main { padding: 0; }
}

/* Guides */
.crumbs { font-size: 13px; color: var(--muted); margin-bottom: 18px; }
.crumbs a { color: var(--muted); }
.prose { max-width: 70ch; }
.prose h2 { margin-top: 2em; padding-top: 1em; border-top: 1px solid var(--rule); font-size: 24px; }
.prose h3 { margin-top: 1.6em; font-size: 18px; }
.prose ul, .prose ol { padding-left: 1.25em; margin: 0 0 1em; }
.prose li { margin-bottom: .4em; }
.prose table { margin: 0 0 1.4em; }
.prose .formula { margin-bottom: 1em; }
.prose .example { border: 1px solid var(--rule-strong); background: var(--panel); padding: 14px 16px; margin: 0 0 1.4em; font-size: 15px; }
.prose .example p { margin: 0 0 .4em; }
.prose .example .calc { font-family: var(--mono); font-size: 14px; }
.sources { font-size: 14px; color: var(--muted); }
.cta { border: 2px solid var(--rule-strong); background: var(--panel); padding: 18px 20px; margin: 2em 0; max-width: 70ch; }
.cta p { margin: 0 0 .8em; }
.guide-list { list-style: none; padding: 0; margin: 28px 0 0; max-width: 70ch; }
.guide-list li { border-top: 1px solid var(--rule); padding: 16px 0; }
.guide-list li:last-child { border-bottom: 1px solid var(--rule); }
.guide-list a.t { font-weight: 600; font-size: 19px; }
.guide-list p { margin: 4px 0 0; color: #2c3742; }