:root {
  --paper: #f4f2eb;
  --card: #ffffff;
  --ink: #13261d;
  --muted: #5b6a61;
  --line: #e1dccf;
  --green: #1d6a45;
  --green-deep: #14382a;
  --green-soft: #e2eee6;
  --flag: #d99a1e;
  --bar-from: #3b9a66;
  --bar-to: #1d6a45;
  --radius: 16px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #0e1813;
    --card: #14211a;
    --ink: #e6eee8;
    --muted: #97a99e;
    --line: #25382d;
    --green: #5cc28b;
    --green-deep: #e6eee8;
    --green-soft: #1b3326;
    --flag: #f0bf4c;
    --bar-from: #4fb27b;
    --bar-to: #2c8255;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 16px/1.55 ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  -webkit-text-size-adjust: 100%;
}

a { color: var(--green); }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 3px solid var(--flag); outline-offset: 2px; }

.site-header, main, .site-footer { max-width: 1080px; margin: 0 auto; padding-left: 16px; padding-right: 16px; }

.site-header { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding-top: 16px; padding-bottom: 8px; }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 750; text-decoration: none; letter-spacing: -0.01em; }
.brand em { color: var(--muted); font-weight: 500; }
.site-header nav { display: flex; gap: 18px; font-size: 14px; }
.site-header nav a { color: var(--muted); text-decoration: none; }
.site-header nav a:hover { color: var(--ink); }

.hero { padding: 28px 0 22px; }
.hero h1 { margin: 0 0 10px; font-size: clamp(32px, 5.4vw, 52px); line-height: 1.04; letter-spacing: -0.025em; font-weight: 820; max-width: 15ch; }
.lead { margin: 0; max-width: 60ch; color: var(--muted); font-size: 18px; }

.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }

.calculator { display: grid; grid-template-columns: minmax(290px, 360px) minmax(0, 1fr); gap: 18px; align-items: start; }

fieldset { border: 0; margin: 0; padding: 0; min-width: 0; }
.field + .field { margin-top: 24px; }
.field-label { display: block; margin: 0 0 10px; padding: 0; font-size: 12px; font-weight: 750; letter-spacing: 0.09em; text-transform: uppercase; color: var(--muted); }
.help { margin: 8px 0 0; font-size: 13px; color: var(--muted); }
input[aria-invalid="true"] { color: #b3261e; }

.speed-input { display: flex; align-items: center; gap: 8px; }
.speed-input input {
  flex: 1; min-width: 0; width: 100%;
  border: 0; background: transparent; color: var(--ink);
  font: inherit; font-size: 52px; font-weight: 820; letter-spacing: -0.03em; line-height: 1.1;
  text-align: right; font-variant-numeric: tabular-nums;
  -moz-appearance: textfield; appearance: textfield;
}
.speed-input input::-webkit-outer-spin-button, .speed-input input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.speed-unit { flex: 1; font-size: 18px; font-weight: 650; color: var(--muted); }
.step {
  flex: none; width: 44px; height: 44px; border-radius: 50%;
  border: 1px solid var(--line); background: var(--paper); color: var(--ink);
  font: inherit; font-size: 22px; line-height: 1; cursor: pointer;
}
.step:hover { border-color: var(--green); color: var(--green); }

input[type="range"] { width: 100%; margin: 14px 0 2px; accent-color: var(--green); }
.quick { display: none; margin: 10px 0 0; padding: 10px 12px; border-radius: 12px; background: var(--green-soft); font-size: 15px; font-variant-numeric: tabular-nums; }
.quick b { color: var(--green-deep); }
.quick a { float: right; font-size: 14px; }

.presets { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 12px; }
.presets button {
  border: 1px solid var(--line); background: var(--paper); color: var(--ink);
  border-radius: 999px; padding: 5px 11px; font: inherit; font-size: 13px; cursor: pointer;
}
.presets button b { font-variant-numeric: tabular-nums; }
.presets button[aria-pressed="true"] { background: var(--green-soft); border-color: var(--green); color: var(--green); }

.segmented { display: grid; grid-auto-flow: column; grid-auto-columns: 1fr; gap: 2px; padding: 4px; background: var(--paper); border: 1px solid var(--line); border-radius: 12px; }
.segmented label { position: relative; }
.segmented input { position: absolute; opacity: 0; inset: 0; margin: 0; cursor: pointer; }
.segmented span { display: block; padding: 8px 6px; border-radius: 9px; text-align: center; font-size: 14px; cursor: pointer; white-space: nowrap; }
.segmented input:checked + span { background: var(--card); color: var(--green); font-weight: 700; box-shadow: 0 1px 3px rgb(0 0 0 / 0.12); }
.segmented input:focus-visible + span { outline: 3px solid var(--flag); outline-offset: 1px; }
.segmented.compact span { padding: 6px; font-size: 13px; }
.unit-row { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }

.eyebrow { margin: 0; font-size: 12px; font-weight: 750; letter-spacing: 0.09em; text-transform: uppercase; color: var(--muted); }
.big { margin: 2px 0 4px; font-size: clamp(56px, 9vw, 84px); font-weight: 850; line-height: 1; letter-spacing: -0.04em; color: var(--green-deep); font-variant-numeric: tabular-nums; }
.big .unit { margin-left: 8px; font-size: 22px; font-weight: 650; letter-spacing: 0; color: var(--muted); }
.sub { margin: 0; font-size: 14px; color: var(--muted); }

.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(118px, 1fr)); gap: 8px; margin: 18px 0 22px; }
.stats div { background: var(--paper); border: 1px solid var(--line); border-radius: 12px; padding: 10px 12px; }
.stats dt { font-size: 12px; color: var(--muted); }
.stats dd { margin: 2px 0 0; font-size: 18px; font-weight: 750; font-variant-numeric: tabular-nums; }

.table-title { margin: 0 0 6px; font-size: 16px; }
table { width: 100%; border-collapse: collapse; font-variant-numeric: tabular-nums; }
th, td { text-align: left; padding: 8px 6px; border-bottom: 1px solid var(--line); vertical-align: middle; }
thead th { font-size: 12px; font-weight: 700; color: var(--muted); }
tbody th { font-weight: 650; white-space: nowrap; }
.num { text-align: right; }
.muted { color: var(--muted); }
.bag td, .bag th { padding-top: 7px; padding-bottom: 7px; }
.carry-cell { width: 58%; }
.carry-wrap { display: flex; align-items: center; gap: 10px; }
.track { flex: 1; height: 10px; border-radius: 6px; background: var(--green-soft); overflow: hidden; }
.bar { display: block; height: 100%; border-radius: 6px; background: linear-gradient(90deg, var(--bar-from), var(--bar-to)); transition: width 160ms ease-out; }
.carry-wrap b { min-width: 3ch; text-align: right; font-size: 16px; }
.note { margin: 12px 0 0; font-size: 13px; color: var(--muted); }

.prose, .fit { margin-top: 18px; }
.prose h2, .fit h2 { margin: 0 0 8px; font-size: 24px; letter-spacing: -0.01em; }
.prose h3 { margin: 18px 0 4px; font-size: 17px; }
.prose p, .prose li { max-width: 72ch; }
.prose ol, .prose ul { padding-left: 22px; margin: 10px 0 0; }
.prose li + li { margin-top: 8px; }

.table-scroll { overflow-x: auto; margin-top: 12px; -webkit-overflow-scrolling: touch; }
.chart { min-width: 560px; font-size: 15px; }
.chart thead th { vertical-align: bottom; }
.chart tbody td { white-space: nowrap; }
.chart tbody tr:nth-child(odd) { background: var(--paper); }
.chart tbody th a { font-weight: 700; text-decoration: none; }
.chart tbody th a:hover { text-decoration: underline; }

.fit { padding: 0; }
.fit h2 { margin: 30px 0 12px; }
.fit-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.fit-card p { margin: 8px 0 0; }
.fit-value { margin: 4px 0 0 !important; font-size: 36px; font-weight: 820; letter-spacing: -0.02em; color: var(--green-deep); }
.fit-near { font-size: 14px; color: var(--flag); font-weight: 650; }
.bands { margin-top: 14px; font-size: 14px; }
.bands tr.current td { background: var(--green-soft); color: var(--green); font-weight: 700; }

.site-footer { padding-top: 24px; padding-bottom: 40px; font-size: 13px; color: var(--muted); }

@media (max-width: 820px) {
  .calculator { grid-template-columns: minmax(0, 1fr); }
  .quick { display: block; }
  .fit-grid { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 560px) {
  .site-header nav { display: none; }
  .hero { padding: 18px 0 16px; }
  .lead { font-size: 16px; }
  .card { padding: 16px; }
  .speed-input input { font-size: 44px; }
  .bag { font-size: 14px; }
  .bag th, .bag td { padding-left: 3px; padding-right: 3px; }
  .carry-wrap { gap: 6px; }
  .prose h2, .fit h2 { font-size: 21px; }
}