:root {
  --bg: #efe6d1;
  --bg-card: #f8f1e1;
  --bg-card-subtle: #f2ead6;
  --border: #d3c19c;
  --border-light: #c1ab7e;
  --ink: #2c2013;
  --ink-soft: #5c4c34;
  --ink-muted: #8c795a;
  --rust: #a8451f;
  --rust-soft: #c25a2e;
  --rust-dim: rgba(168, 69, 31, 0.1);
  --indigo: #35506b;
  --indigo-dim: rgba(53, 80, 107, 0.1);
  --gold: #93701f;
  --gold-dim: rgba(147, 112, 31, 0.12);
  --green: #4b6b3f;
  --serif: "Spectral", Georgia, "Times New Roman", serif;
  --display: "Fraunces", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: "Space Mono", "JetBrains Mono", ui-monospace, SFMono-Regular, monospace;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  font-size: 17px;
  background-color: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  line-height: 1.68;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  min-height: 100vh;
  background-image:
    radial-gradient(circle at 15% 20%, rgba(147, 112, 31, 0.05), transparent 45%),
    radial-gradient(circle at 85% 75%, rgba(168, 69, 31, 0.05), transparent 45%);
}

.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}
.visually-hidden:focus {
  position: fixed; top: 1rem; left: 1rem; width: auto; height: auto;
  padding: 0.6rem 1rem; margin: 0; background: var(--ink); color: var(--bg);
  z-index: 999; border-radius: 4px;
}

img, svg, canvas { max-width: 100%; }

.shell { max-width: 44rem; margin: 0 auto; padding: 0 1.5rem; }
.shell-wide { max-width: 54rem; margin: 0 auto; padding: 0 1.5rem; }

/* Topbar */
.topbar {
  display: flex; justify-content: space-between; align-items: center;
  padding: 1.5rem 1.5rem; max-width: 54rem; margin: 0 auto;
  font-family: var(--sans); font-size: 0.9rem;
}
.brand { color: var(--ink); text-decoration: none; font-weight: 600; letter-spacing: 0.01em; }
.brand:hover { color: var(--rust); }
.langsw a { color: var(--ink-muted); text-decoration: none; }
.langsw a[aria-current="page"] { color: var(--rust); font-weight: 700; }
.langsw a:hover { color: var(--ink); }

/* Hero */
.hero { padding: 2rem 0 3rem; border-bottom: 1px solid var(--border); }
.kicker {
  font-family: var(--sans); font-size: 0.78rem; font-weight: 700;
  letter-spacing: 0.12em; text-transform: uppercase; color: var(--rust);
  margin-bottom: 1rem;
}
.hero h1 {
  font-family: var(--display); font-optical-sizing: auto;
  font-weight: 600; font-size: clamp(2.1rem, 5.5vw, 3.2rem);
  line-height: 1.12; letter-spacing: -0.01em; margin-bottom: 1.3rem;
  color: var(--ink);
}
.standfirst {
  font-size: 1.14rem; color: var(--ink-soft); max-width: 40rem;
  margin-bottom: 2.2rem;
}

.ledgerline {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 1px;
  background: var(--border); border: 1px solid var(--border);
  border-radius: 3px; overflow: hidden;
}
.ledgerline > div {
  background: var(--bg-card); padding: 1.1rem 1.3rem;
  display: flex; flex-direction: column; gap: 0.3rem;
}
.ledgerline .n {
  font-family: var(--mono); font-weight: 700; font-size: 1.4rem; color: var(--rust);
}
.ledgerline .l {
  font-family: var(--sans); font-size: 0.82rem; color: var(--ink-muted); line-height: 1.4;
}

/* Blocks / prose */
.block { padding: 3rem 0; }
.prose h2 {
  font-family: var(--display); font-weight: 600; font-size: 1.7rem;
  color: var(--ink); margin-bottom: 1.1rem; letter-spacing: -0.005em;
}
.prose h3 {
  font-family: var(--display); font-weight: 600; font-size: 1.25rem;
  color: var(--ink); margin: 1.6rem 0 0.7rem;
}
.prose p { margin-bottom: 1.1rem; color: var(--ink); }
.prose p:last-child { margin-bottom: 0; }
.prose em { color: var(--rust-soft); font-style: italic; }
.prose strong { color: var(--ink); font-weight: 700; }
.prose a { color: var(--indigo); }

.divider {
  border: none; border-top: 1px solid var(--border); max-width: 44rem;
  margin: 0 auto;
}

/* Ruler instrument */
.ruler-wrap { margin-top: 1.6rem; }
.ruler-row {
  display: grid; grid-template-columns: 13rem 1fr 5rem; align-items: center;
  gap: 0.9rem; padding: 0.55rem 0;
}
.ruler-label {
  font-family: var(--sans); font-size: 0.82rem; color: var(--ink-soft); line-height: 1.3;
}
.ruler-track { position: relative; height: 1.4rem; }
.ruler-bar {
  height: 100%; border-radius: 2px; background: var(--rust-dim);
  border: 1px solid var(--rust-soft); position: relative;
}
.ruler-bar.alt { background: var(--indigo-dim); border-color: var(--indigo); }
.ruler-val {
  font-family: var(--mono); font-size: 0.85rem; font-weight: 700; color: var(--ink);
  text-align: right;
}
.ruler-scale {
  font-family: var(--mono); font-size: 0.7rem; color: var(--ink-muted);
  display: flex; justify-content: space-between; margin-top: 0.3rem;
  padding-left: 13.9rem;
}

/* Instrument (converter) */
.instrument { padding: 3rem 0; background: var(--bg-card-subtle); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.controls { margin: 1.6rem 0; }
.ctrl-row { display: flex; flex-wrap: wrap; gap: 1.2rem; align-items: flex-end; }
.ctrl { display: flex; flex-direction: column; gap: 0.4rem; }
.ctrl label {
  font-family: var(--sans); font-size: 0.75rem; font-weight: 700;
  letter-spacing: 0.04em; text-transform: uppercase; color: var(--ink-muted);
}
.region-select, .qty-input {
  font-family: var(--serif); font-size: 1.05rem; color: var(--ink);
  background: var(--bg-card); border: 1px solid var(--border-light);
  border-radius: 4px; padding: 0.55rem 0.8rem; min-width: 12rem;
}
.qty-input { min-width: 7rem; font-family: var(--mono); }
.region-select:focus, .qty-input:focus { outline: 2px solid var(--rust); outline-offset: 1px; }

.converter-result {
  display: grid; grid-template-columns: 1fr 1fr; gap: 1.6rem; margin-top: 1.8rem;
}
@media (max-width: 640px) { .converter-result { grid-template-columns: 1fr; } }

.square-panel {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 6px; padding: 1.4rem; display: flex; flex-direction: column;
  align-items: center; justify-content: center; min-height: 16rem;
}
.square-stage {
  position: relative; width: 100%; aspect-ratio: 1; max-width: 14rem;
  display: flex; align-items: center; justify-content: center;
}
.square-shape {
  position: absolute; background: var(--rust-dim); border: 2px solid var(--rust);
  border-radius: 2px; transition: width 0.3s ease, height 0.3s ease;
}
.square-caption {
  font-family: var(--mono); font-size: 0.78rem; color: var(--ink-muted);
  margin-top: 1rem; text-align: center;
}

.readouts-panel { display: flex; flex-direction: column; gap: 0.9rem; }
.readout-primary {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 6px;
  padding: 1.1rem 1.3rem;
}
.readout-primary .r-num {
  font-family: var(--mono); font-weight: 700; font-size: 1.6rem; color: var(--rust);
  display: block;
}
.readout-primary .r-txt {
  font-family: var(--sans); font-size: 0.82rem; color: var(--ink-muted); margin-top: 0.3rem;
}

.equiv-table { border: 1px solid var(--border); border-radius: 6px; overflow: hidden; }
.equiv-row {
  display: flex; justify-content: space-between; align-items: baseline;
  padding: 0.65rem 1rem; background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  font-family: var(--sans); font-size: 0.88rem;
}
.equiv-row:last-child { border-bottom: none; }
.equiv-row.active { background: var(--gold-dim); }
.equiv-row .e-region { color: var(--ink-soft); }
.equiv-row .e-val { font-family: var(--mono); font-weight: 700; color: var(--ink); }

/* Ledger / method block */
.block.ledger { background: var(--bg-card-subtle); border-top: 1px solid var(--border); }
.srcrow { margin-bottom: 1.4rem; }
.srcrow:last-child { margin-bottom: 0; }
.srcrow .tag {
  font-family: var(--sans); font-size: 0.72rem; font-weight: 700;
  letter-spacing: 0.08em; text-transform: uppercase; color: var(--rust);
  margin-bottom: 0.35rem;
}
.srcrow p { color: var(--ink-soft); font-size: 0.95rem; margin-bottom: 0.5rem; }
.srcrow p.meta { color: var(--ink-muted); font-size: 0.88rem; }

/* Footer */
footer.site {
  padding: 2rem 1.5rem 3rem; max-width: 54rem; margin: 0 auto;
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 0.6rem;
  font-family: var(--sans); font-size: 0.82rem; color: var(--ink-muted);
}
footer.site a { color: var(--ink-muted); }
footer.site a:hover { color: var(--rust); }

.totop {
  position: fixed; bottom: 1.5rem; right: 1.5rem; width: 2.6rem; height: 2.6rem;
  border-radius: 50%; background: var(--ink); color: var(--bg);
  display: flex; align-items: center; justify-content: center;
  text-decoration: none; font-size: 1.1rem; opacity: 0; pointer-events: none;
  transition: opacity 0.2s ease; box-shadow: 0 2px 8px rgba(0,0,0,0.2);
}
.totop.visible { opacity: 0.85; pointer-events: auto; }
.totop:hover { opacity: 1; }

@media (max-width: 640px) {
  html { font-size: 16px; }
  .ledgerline { grid-template-columns: 1fr; }
  .ruler-row { grid-template-columns: 1fr; gap: 0.3rem; }
  .ruler-val { text-align: left; }
  .ruler-scale { padding-left: 0; }
  .ctrl-row { flex-direction: column; align-items: stretch; }
  .region-select, .qty-input { min-width: 0; }
}

.no-js .js-only { display: none; }