:root {
  --bg: #eef3f0;
  --surface: #ffffff;
  --ink: #17201d;
  --muted: #3b4944;
  --line: #a9bab3;
  --field: #788c84;
  --accent: #1d6353;
  --accent-ink: #ffffff;
  --accent-soft: #d7e8e1;
  --err: #a1251a;
  --tick: #17201d;
  --shrink: #f6e9cf;
  --real: #e3ebe7;
  --r: 6px;
  --head: "Avenir Next", Avenir, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --body: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121816;
    --surface: #1a2320;
    --ink: #e4ece8;
    --muted: #b6c4be;
    --line: #47584f;
    --field: #6b7f76;
    --accent: #84cdb9;
    --accent-ink: #0b1411;
    --accent-soft: #23362f;
    --err: #ff9b8c;
    --tick: #e4ece8;
    --shrink: #3b3222;
    --real: #26312d;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.55 var(--body); }
a { color: var(--accent); text-underline-offset: 2px; }
.wrap { max-width: 1120px; margin: 0 auto; padding: 0 16px; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.skip { position: absolute; left: -9999px; top: 0; background: var(--surface); color: var(--ink); padding: 8px 12px; z-index: 10; }
.skip:focus { left: 8px; top: 8px; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }

/* A strip of ruler ticks along the top: the one decoration, and it is the subject. */
.top { border-bottom: 1px solid var(--line); background:
  repeating-linear-gradient(90deg, var(--ink) 0 1px, transparent 1px 100%) bottom left / 40px 12px repeat-x,
  repeating-linear-gradient(90deg, var(--ink) 0 1px, transparent 1px 100%) bottom left / 10px 6px repeat-x; }
.top-in { padding: 14px 16px 20px; }
.brand { font: 700 18px/1.2 var(--head); color: var(--ink); text-decoration: none; letter-spacing: 0.01em; }

.intro { padding: 22px 0 6px; max-width: 46rem; }
h1 { font: 700 clamp(28px, 5vw, 40px)/1.12 var(--head); margin: 0 0 8px; letter-spacing: -0.01em; }
.lede { margin: 0; color: var(--muted); font-size: 18px; }
h2 { font: 700 22px/1.25 var(--head); margin: 0 0 12px; }
h3 { font: 700 18px/1.3 var(--head); margin: 22px 0 6px; }

.tool { display: grid; gap: 16px; margin: 18px 0 8px; grid-template-columns: minmax(0, 1fr); }
@media (min-width: 900px) {
  .tool { grid-template-columns: minmax(0, 5fr) minmax(0, 6fr); grid-template-areas: "in res" "opts res"; align-items: start; }
  .inputs { grid-area: in; }
  .result { grid-area: res; position: sticky; top: 16px; }
  .opts { grid-area: opts; }
}
.panel { min-width: 0; }
.inputs, .opts { padding: 0; }
.result { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); padding: 18px; min-height: 210px; }

fieldset { border: 0; margin: 0 0 14px; padding: 0; min-width: 0; }
legend { font: 700 17px/1.3 var(--head); padding: 0; margin-bottom: 8px; }
.seg { display: flex; flex-wrap: wrap; gap: 0; }
.seg legend { width: 100%; }
.seg-opt { position: relative; }
.seg-opt input { position: absolute; opacity: 0; inset: 0; margin: 0; cursor: pointer; }
.seg-opt span { display: inline-flex; align-items: center; min-height: 44px; padding: 6px 14px; border: 1.5px solid var(--field); margin-left: -1.5px; background: var(--surface); color: var(--ink); font-size: 16px; white-space: nowrap; cursor: pointer; }
.seg-opt:first-of-type span { border-radius: var(--r) 0 0 var(--r); margin-left: 0; }
.seg-opt:last-of-type span { border-radius: 0 var(--r) var(--r) 0; }
.seg-opt input:checked + span { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); position: relative; z-index: 1; }
.seg-opt input:focus-visible + span { outline: 3px solid var(--accent); outline-offset: 2px; z-index: 2; }

.field { display: block; margin: 0 0 12px; min-width: 0; }
.field > span:first-child { display: block; font-weight: 600; margin-bottom: 4px; }
input[type=text], select {
  width: 100%; min-height: 46px; font: 17px/1.3 var(--body); color: var(--ink); background: var(--surface);
  border: 1.5px solid var(--field); border-radius: var(--r); padding: 8px 10px;
}
input[aria-invalid=true] { border-color: var(--err); }
.suffix { display: flex; align-items: center; gap: 8px; max-width: 12rem; }
.suffix b { font-size: 18px; }
#f-p { font-size: 22px; font-weight: 700; }
.pair { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; align-items: end; }
.pair .seg { margin-bottom: 12px; }
.hint { margin: -2px 0 8px; color: var(--muted); font-size: 16px; }
.err { color: var(--err); margin: 0 0 10px; font-weight: 600; }
.err-inline { color: var(--err); font-weight: 600; }

.answer { font: 400 20px/1.3 var(--head); margin: 0 0 6px; }
.answer b { font-size: 44px; line-height: 1; margin-right: 4px; }
.exact { color: var(--muted); font-size: 16px; }
.answer-sub { margin: 0 0 10px; }
.note { margin: 0 0 10px; padding: 8px 10px; background: var(--accent-soft); border-radius: var(--r); }
.res-wait { margin: 0; font-weight: 600; color: var(--err); }
.preview svg { display: block; width: 100%; max-width: 400px; height: auto; }
.preview .shrink { fill: var(--shrink); stroke: var(--tick); stroke-width: 0.25; }
.preview .real { fill: var(--real); stroke: var(--tick); stroke-width: 0.25; }
.preview .tick { stroke: var(--tick); }
.preview .num { fill: var(--tick); font-family: var(--body); font-weight: 700; }
.preview .lbl { fill: var(--tick); font-family: var(--body); font-weight: 600; }

.opts h2 { margin-top: 4px; }
.print-sum { margin: 2px 0 10px; }
.tip { margin: 10px 0 0; color: var(--muted); }
.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin: 6px 0; }
.btn {
  display: inline-flex; align-items: center; justify-content: center; min-height: 46px; padding: 8px 18px;
  font: 600 17px/1.2 var(--body); color: var(--ink); background: var(--surface); border: 1.5px solid var(--field);
  border-radius: var(--r); cursor: pointer; text-decoration: none;
}
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn:disabled { opacity: 0.55; cursor: not-allowed; }
.btn.quiet { background: transparent; }
.btn.small { min-height: 44px; padding: 6px 12px; font-size: 16px; }
#share-note, #reset-note { font-size: 16px; }

.card-sec { margin: 30px 0 10px; padding-top: 22px; border-top: 2px solid var(--ink); }
.sec-lede { margin: -4px 0 14px; }
.card-opts { display: flex; flex-wrap: wrap; gap: 0 18px; align-items: flex-end; }
.card-opts .seg { margin-bottom: 12px; }
.field.narrow { width: 9rem; }
#rows { display: grid; gap: 12px; margin: 4px 0 10px; }
.row { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0 10px; padding: 12px 0; border-bottom: 1px solid var(--line); align-items: end; }
.row .rn { grid-column: 1 / -1; max-width: 22rem; }
.row .field { margin-bottom: 8px; }
.row .field > span:first-child { font-size: 16px; }
.row-out { grid-column: 1 / -1; margin: 0 0 6px; min-height: 1.55em; }
.row .del { grid-column: 1 / -1; justify-self: start; }
.empty { color: var(--muted); }
@media (min-width: 760px) {
  .row { grid-template-columns: minmax(0, 1.4fr) repeat(3, minmax(0, 1fr)) auto; align-items: end; }
  .row .rn { grid-column: auto; }
  .row .del { grid-column: auto; margin-bottom: 8px; }
  .row-out { grid-row: 2; grid-column: 1 / -1; }
}
.quick { margin: 12px 0; }
.quick summary, #earlier summary { cursor: pointer; font-weight: 600; padding: 10px 0; display: list-item; }
.qt { display: flex; flex-wrap: wrap; gap: 14px 28px; }
.qt table { border-collapse: collapse; font-variant-numeric: tabular-nums; }
.qt th, .qt td { text-align: left; padding: 5px 12px 5px 0; border-bottom: 1px solid var(--line); font-size: 16px; }
.qt td { white-space: nowrap; }
.qt th { font-weight: 700; vertical-align: bottom; max-width: 8.5rem; }

.saved-sec { margin: 8px 0 20px; }
.save-note { padding: 8px 10px; background: var(--accent-soft); border-radius: var(--r); }
#earlier-list { list-style: none; padding: 0; margin: 4px 0 8px; }
#earlier-list li { display: flex; flex-wrap: wrap; gap: 6px 12px; align-items: center; padding: 6px 0; border-bottom: 1px solid var(--line); }

.content { max-width: 46rem; padding: 10px 0 30px; }
.content h2 { margin-top: 28px; }
.formulas { padding-left: 20px; }
.formulas li { margin-bottom: 6px; }
.faq h3 { margin-top: 18px; }
.faq p { margin: 0 0 6px; }
.sources { color: var(--muted); margin-top: 22px; }

.toast { position: fixed; left: 50%; bottom: 16px; transform: translateX(-50%); z-index: 20; display: flex; gap: 12px; align-items: center;
  background: var(--ink); color: var(--bg); padding: 8px 10px 8px 16px; border-radius: var(--r); max-width: calc(100vw - 32px); }
.toast[hidden] { display: none; }
.toast .btn { background: var(--bg); color: var(--ink); border-color: var(--bg); }

.foot { border-top: 1px solid var(--line); padding: 18px 0 30px; }
.sb-footer { font-size: 16px; color: var(--muted); }
.sb-more { margin: 0 0 10px; line-height: 1.7; }
.sb-privacy, .sb-credit { margin: 0 0 6px; }
.sb-footer a { color: var(--ink); }

#print-root { display: none; }
@media (prefers-reduced-motion: reduce) { * { transition: none !important; animation: none !important; } }

@page { margin: 10mm; }
@media print {
  body { background: #fff; color: #000; font: 11pt/1.4 Arial, Helvetica, sans-serif; }
  body > *:not(#print-root) { display: none !important; }
  #print-root { display: block; }
  #print-root svg.sheet { display: block; break-after: page; page-break-after: always; overflow: hidden; }
  .pcard h2 { font: 700 17pt/1.2 Arial, sans-serif; margin: 0 0 1.5mm; }
  .pmeta { margin: 0 0 5mm; font-size: 11pt; }
  .pcard table { border-collapse: collapse; font-variant-numeric: tabular-nums; break-inside: avoid; }
  .pc { width: calc(100% - 1mm); margin-bottom: 7mm; font-size: 11pt; }
  .pc th, .pc td { border: 0.25mm solid #555; padding: 1.6mm 2mm; text-align: left; vertical-align: top; }
  .pc thead th { font-size: 10pt; background: none; }
  .pc tbody th { width: 28%; }
  .pc .blank td, .pc .blank th { height: 9mm; }
  .qt { display: flex; gap: 10mm; align-items: flex-start; }
  .qt table { font-size: 10.5pt; }
  .qt th, .qt td { border-bottom: 0.25mm solid #777; padding: 1mm 4mm 1mm 0; font-size: 10.5pt; }
  .qt th { max-width: 30mm; }
  .print-msg { font: 13pt Arial, sans-serif; }
}