:root {
  color-scheme: light;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  color: #182e32;
  background: #f3f5f2;
  font-synthesis: none;
  --muted: #526568;
  --line: #d6dfdb;
  --accent: #115e59;
  --error: #9b2624;
}
* { box-sizing: border-box; }
body { margin: 0; }
main { max-width: 1160px; margin: 0 auto; padding: 48px 28px 24px; }
.page-header { margin-bottom: 34px; }
.eyebrow { display: flex; align-items: center; gap: 16px; text-transform: uppercase; font-size: .75rem; font-weight: 700; letter-spacing: .13em; color: var(--accent); }
.eyebrow span { border-left: 1px solid var(--line); padding-left: 16px; color: var(--muted); }
h1 { font-size: clamp(2rem, 4.5vw, 3.2rem); line-height: 1.12; letter-spacing: -.04em; margin: 18px 0; font-weight: 650; }
.intro { color: var(--muted); line-height: 1.6; margin-bottom: 0; }
.workspace { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 24px; align-items: stretch; }
.panel { background: #fff; border: 1px solid var(--line); border-radius: 14px; padding: 28px; }
.section-heading { display: flex; gap: 12px; align-items: center; margin-bottom: 24px; }
h2 { font-size: 1.13rem; font-weight: 650; margin: 0; }
.step-number { display: grid; place-items: center; width: 30px; height: 30px; border: 1px solid var(--line); border-radius: 50%; font-size: .73rem; color: var(--muted); }
.mode-row { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding-bottom: 18px; border-bottom: 1px solid var(--line); margin-bottom: 20px; }
label { display: block; font-size: .88rem; font-weight: 650; }
select, input, button { font: inherit; }
select { max-width: 65%; padding: 9px 28px 9px 12px; color: inherit; background: #f5f8f6; border: 1px solid #b6c6bf; border-radius: 6px; }
select:disabled { color: #526568; cursor: not-allowed; }
.field { margin-top: 19px; }
.unit { color: var(--muted); font-size: .78rem; font-weight: 400; margin-left: 7px; }
input { width: 100%; min-height: 45px; margin-top: 8px; padding: 10px 12px; color: inherit; background: #fff; border: 1px solid #aabcb3; border-radius: 6px; font-variant-numeric: tabular-nums; }
input[aria-invalid="true"] { border: 2px solid var(--error); }
.help { color: var(--muted); font-size: .76rem; line-height: 1.55; margin: 7px 0 0; }
.error { color: var(--error); font-size: .82rem; line-height: 1.5; margin: 8px 0 0; }
.result-error { padding: 15px; background: #fff3ef; border-left: 3px solid var(--error); }
.actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 25px; }
button { cursor: pointer; border: 1px solid #adbfba; color: var(--accent); background: #fff; border-radius: 6px; padding: 11px 15px; font-size: .83rem; font-weight: 650; min-height: 44px; }
button:hover { background: #eef5f0; }
button:disabled { cursor: not-allowed; color: var(--muted); background: #f3f5f2; }
.copy-actions { margin-bottom: 20px; }
button.primary { background: var(--accent); color: #fff; border-color: var(--accent); margin-right: auto; }
button.primary:hover { background: #094d48; }
:focus-visible { outline: 3px solid #b56800; outline-offset: 3px; }
.precision { margin-top: 17px; }
.results-panel { background: #fafffc; display: flex; flex-direction: column; }
.empty { color: var(--muted); line-height: 1.7; max-width: 27ch; margin: 36px 0; }
.power-group { padding: 0 0 24px; margin: 0 0 24px; border-bottom: 1px solid var(--line); }
h3 { font-size: .9rem; font-weight: 650; margin: 0 0 13px; }
.result-line { margin: 8px 0; display: flex; align-items: baseline; flex-wrap: wrap; gap: 9px; font-size: 1rem; color: var(--muted); overflow-wrap: anywhere; }
.result-line output { font-variant-numeric: tabular-nums; }
.result-line.primary { color: var(--accent); }
.result-line.primary output { font-size: clamp(1.9rem, 3.3vw, 2.7rem); font-weight: 600; letter-spacing: -.04em; line-height: 1.3; }
.result-line span { font-size: .85rem; }
abbr { text-decoration: none; }
.summary { margin-bottom: 20px; }
dl { margin: 0; }
.summary-row { display: grid; grid-template-columns: 1fr 1.2fr; gap: 12px; padding: 8px 0; font-size: .8rem; border-bottom: 1px solid #e7eeea; }
dt { color: var(--muted); }
dd { margin: 0; text-align: right; overflow-wrap: anywhere; }
.result-note { border-top: 1px solid var(--line); padding-top: 17px; margin-top: auto; margin-bottom: 0; color: var(--muted); font-size: .8rem; line-height: 1.6; }
.warning, .demo { border-left: 3px solid #ad7316; background: #fff7e6; color: #67460d; padding: 11px 13px; font-size: .82rem; line-height: 1.5; }
.assumptions { margin-top: 24px; border: 1px solid var(--line); background: #fff; border-radius: 10px; }
summary { cursor: pointer; padding: 20px 24px; font-size: .9rem; font-weight: 650; }
.details-content { padding: 0 24px 20px; line-height: 1.75; font-size: .88rem; max-width: 92ch; }
.details-content h3 { margin-top: 25px; }
.equation { font-size: 1rem; padding: 14px; background: #f3f7f4; border-radius: 6px; }
a { color: var(--accent); text-underline-offset: 3px; }
footer { margin-top: 24px; font-size: .73rem; color: var(--muted); text-align: center; line-height: 1.6; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0; }
[hidden] { display: none !important; }
@media (max-width: 720px) {
  main { padding: 26px 16px 20px; }
  .workspace { grid-template-columns: minmax(0, 1fr); gap: 18px; }
  .panel { padding: 21px; }
  .page-header { margin-bottom: 25px; }
  .empty { margin: 12px 0 28px; max-width: none; }
  .result-note { margin-top: 16px; }
  .result-line.primary output { font-size: 2.2rem; }
  .details-content { padding: 0 20px 20px; }
}