* { box-sizing: border-box; }
:root {
  color-scheme: light;
  --background: #f7f8f4;
  --paper: #fff;
  --ink: #182720;
  --muted: #4e6055;
  --green: #1b5a43;
  --line: #d6ded6;
  --soft: #eaf1ea;
  --radius: 1.1rem;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  line-height: 1.55;
  color: var(--ink);
  background: var(--background);
}
body { margin: 0; }
a { color: var(--green); text-underline-offset: .18em; }
a:hover { text-decoration-thickness: .13em; }
:focus-visible { outline: 3px solid #267654; outline-offset: 3px; }
p, h1, h2, ol, dl, dd { margin: 0; }
.shell { width: min(100% - 2rem, 62rem); margin-inline: auto; }
.header { background: var(--paper); border-bottom: 1px solid var(--line); }
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: .25rem 1.5rem; flex-wrap: wrap; min-height: 4.25rem; padding-block: .6rem; }
.brand { display: inline-flex; align-items: center; gap: .55rem; color: var(--ink); text-decoration: none; font-weight: 750; min-height: 2.75rem; }
.brand-mark {
  width: 1.6rem;
  height: 1.6rem;
  border-radius: .45rem;
  background:
    linear-gradient(white, white) .43rem .34rem / 2px .58rem no-repeat,
    linear-gradient(white, white) .76rem .34rem / 2px .35rem no-repeat,
    linear-gradient(white, white) 1.09rem .34rem / 2px .58rem no-repeat,
    var(--green);
}
.header nav { display: flex; gap: .25rem; flex-wrap: wrap; }
.header nav a { display: inline-flex; align-items: center; min-height: 2.75rem; padding-inline: .6rem; border-radius: .45rem; font-size: .88rem; font-weight: 650; text-decoration: none; }
.header nav a:hover, .header nav a[aria-current] { background: var(--soft); }
main { padding-block: clamp(1.6rem, 4vw, 3.8rem) 3.5rem; }
.breadcrumb { margin-bottom: .9rem; font-size: .9rem; }
.breadcrumb ol { list-style: none; padding: 0; display: flex; gap: .5rem; flex-wrap: wrap; color: var(--muted); }
.breadcrumb li + li::before { content: "/"; margin-right: .5rem; }
.intro { margin-bottom: clamp(1.25rem, 3vw, 2rem); }
h1 { font-size: clamp(2rem, 5.4vw, 3.65rem); font-weight: 760; letter-spacing: -.055em; line-height: 1.05; text-wrap: balance; }
.intro p { color: var(--muted); margin-top: .75rem; max-width: 65ch; }
.calculator {
  display: grid;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: clip;
  box-shadow: 0 .5rem 1.5rem #14251a0b;
}
.controls, .result { min-width: 0; padding: clamp(1.15rem, 3vw, 2rem); }
.controls h2 { font-size: 1.12rem; margin-bottom: 1.15rem; }
.field { display: grid; min-width: 0; gap: .35rem; font-size: .9rem; font-weight: 680; }
.input-wrap { display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: center; gap: .25rem; padding-inline: .8rem; border: 1px solid #a6b4a8; border-radius: .55rem; background: #f9faf8; }
.input-wrap:focus-within { outline: 2px solid var(--green); outline-offset: 1px; }
.input-wrap:has(input[aria-invalid]) { border-color: #a12222; }
input { width: 100%; min-height: 2.9rem; border: 0; outline: none; background: transparent; color: var(--ink); font: inherit; font-size: 1.12rem; font-variant-numeric: tabular-nums; padding: .25rem 0; }
input:disabled { opacity: 1; }
.unit { color: var(--muted); font-size: .85rem; }
.pair { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: .75rem; }
.field + .pair { margin-top: .85rem; }
.hint, .error, noscript { font-size: .88rem; }
.hint, noscript { color: var(--muted); margin-top: .75rem; }
.error { color: #a12222; margin-top: .4rem; }
.result { background: #163a2d; color: #f3faf4; }
.result-label { font-size: .9rem; font-weight: 650; color: #c5e6d4; }
.result-number { font-size: clamp(2rem, 6.4vw, 3.55rem); font-weight: 750; line-height: 1.12; letter-spacing: -.045em; margin-block: .25rem .85rem; overflow-wrap: anywhere; }
.result-number, dd, td { font-variant-numeric: tabular-nums; }
.details div { display: flex; gap: .4rem 1rem; align-items: baseline; justify-content: space-between; border-top: 1px solid #ffffff30; padding-block: .45rem; }
.details dt { color: #c5e6d4; font-size: .89rem; }
.details dd { text-align: right; overflow-wrap: anywhere; font-weight: 650; }
.copy-row { display: flex; align-items: center; flex-wrap: wrap; gap: .35rem .65rem; margin-top: .75rem; font-size: .85rem; }
button { font: inherit; font-weight: 700; border: 1px solid #fff5; border-radius: .5rem; background: #e3f3e9; color: #163a2d; padding: .42rem .8rem; min-height: 2.75rem; cursor: pointer; }
button:hover:enabled { background: #fff; }
button:disabled { opacity: .65; cursor: default; }
.result :focus-visible { outline-color: #e3f3e9; }
.sections { display: grid; gap: 1rem; margin-top: 1.3rem; }
.panel { border: 1px solid var(--line); border-radius: var(--radius); background: var(--paper); padding: clamp(1rem, 3vw, 1.55rem); }
.panel h2 { font-size: clamp(1.12rem, 3vw, 1.35rem); line-height: 1.25; margin-bottom: .6rem; }
.panel p + p { margin-top: .55rem; }
.panel ol { padding-left: 1.3rem; }
.height-links { list-style: none; display: flex; flex-wrap: wrap; gap: .4rem; margin: 0; padding: 0; }
.height-links a { display: inline-flex; align-items: center; min-height: 2.75rem; background: var(--soft); border-radius: .45rem; padding: .4rem .7rem; font-size: .88rem; font-weight: 650; }
.equation { font-weight: 680; }
.chart { background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); overflow: clip; }
table { border-collapse: collapse; width: 100%; table-layout: fixed; font-size: clamp(.8rem, 2.5vw, 1rem); }
th, td { padding: .7rem clamp(.4rem, 2vw, 1.25rem); text-align: left; overflow-wrap: anywhere; }
thead { background: var(--soft); }
tbody tr { border-top: 1px solid var(--line); }
.footer { border-top: 1px solid var(--line); padding-block: 1.2rem; color: var(--muted); font-size: .85rem; }
.visually-hidden, .skip-link:not(:focus) { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
.skip-link:focus { position: absolute; z-index: 1; top: .5rem; left: .5rem; background: var(--paper); padding: .5rem; }
@media (min-width: 43rem) {
  .calculator { grid-template-columns: 1fr 1fr; }
  .header nav a { padding-inline: .85rem; }
}