/* Plinthly — drafting-sheet UI. Neutrals from Arch21 charcoal (#2D2D2D); Plinthly's own highlight is blueprint blue;
   Arch21 orange (#F8B133) is reserved for links to the parent company. Plex Sans + Plex Mono for figures. */
:root {
  --paper: #F5F5F3;
  --surface: #FFFFFF;
  --sunken: #EFEFED;
  --ink: #2D2D2D;
  --ink-2: #4A4A4A;
  --muted: #646462;
  --line: #DDDDDA;
  --line-2: #C6C6C2;
  --grid: #E7E7E4;
  --arch21: #F8B133;
  --arch21-ink: #2D2D2D;
  --arch21-link: #2D2D2D;
  --accent: #1D4ED8;
  --accent-hover: #1E3A8A;
  --accent-ink: #FFFFFF;
  --accent-soft: #E8EEFC;
  --ok: #1E6B3A;
  --ok-bg: #E6F3EA;
  --bad: #A3241B;
  --bad-bg: #FBEAE8;
  --warn: #6E3C00;
  --warn-bg: #FFF4E2;
  --warn-line: #EBCB98;
  --font-sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --radius: 10px;
  --wrap: 1240px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #232323; --surface: #2D2D2D; --sunken: #1C1C1C; --ink: #F2F2F0; --ink-2: #CFCFCB; --muted: #A3A3A0;
    --line: #3D3D3D; --line-2: #4F4F4F; --grid: #2A2A2A; --arch21-link: #F8B133; --accent: #86A8FF; --accent-hover: #B3C8FF; --accent-ink: #0D1220;
    --accent-soft: #1C2740; --ok: #7BD39A; --ok-bg: #15281C; --bad: #FF9C92; --bad-bg: #2E1716; --warn: #F2C27A; --warn-bg: #2A2114; --warn-line: #5A4420;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #232323; --surface: #2D2D2D; --sunken: #1C1C1C; --ink: #F2F2F0; --ink-2: #CFCFCB; --muted: #A3A3A0;
  --line: #3D3D3D; --line-2: #4F4F4F; --grid: #2A2A2A; --arch21-link: #F8B133; --accent: #86A8FF; --accent-hover: #B3C8FF; --accent-ink: #0D1220;
  --accent-soft: #1C2740; --ok: #7BD39A; --ok-bg: #15281C; --bad: #FF9C92; --bad-bg: #2E1716; --warn: #F2C27A; --warn-bg: #2A2114; --warn-line: #5A4420;
  color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
body {
  margin: 0; background: var(--paper); color: var(--ink);
  font-family: var(--font-sans); font-size: 16px; line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); }
a:hover { color: var(--accent-hover); }
h1, h2, h3 { text-wrap: balance; margin: 0; }
.num, .mono { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
:focus-visible { outline: 2.5px solid var(--accent); outline-offset: 2px; }

.wrap {
  max-width: var(--wrap); margin: 0 auto;
  padding-left: max(24px, env(safe-area-inset-left, 0px));
  padding-right: max(24px, env(safe-area-inset-right, 0px));
}
@media (max-width: 600px) {
  .wrap { padding-left: max(16px, env(safe-area-inset-left, 0px)); padding-right: max(16px, env(safe-area-inset-right, 0px)); }
}

/* Header */
.site-head { background: var(--surface); border-bottom: 1px solid var(--line); }
.site-head .wrap { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 12px 20px; padding-block: 12px; }
.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); min-height: 44px; }
.brand:hover { color: var(--ink); }
.brand svg { flex: none; }
.brand .plinth-top { stroke: var(--ink); }
.brand .plinth-base { fill: var(--accent); }
.brand b { font-size: 20px; font-weight: 700; letter-spacing: -0.02em; }
.site-nav { display: flex; flex-wrap: wrap; align-items: center; gap: 4px 18px; font-size: 15px; }
.site-nav a { color: var(--ink); text-decoration: none; font-weight: 500; padding: 10px 0; }
.site-nav a:hover { color: var(--accent); }
.site-nav a[aria-current="page"] { color: var(--accent); }
.by { color: var(--muted); font-size: 13px; }

/* Page head */
.page-head { padding-block: 28px 8px; display: flex; flex-direction: column; gap: 8px; }
.crumbs { font-size: 14px; color: var(--muted); }
.crumbs a { color: var(--muted); }
.page-head h1 { font-size: clamp(28px, 4vw, 36px); letter-spacing: -0.02em; font-weight: 700; line-height: 1.15; }
.page-head p { margin: 0; color: var(--ink-2); max-width: 68ch; }
.eyebrow { font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.08em; color: var(--muted); text-transform: uppercase; }

/* Tool layout: inputs left, results right */
.tool { display: flex; flex-wrap: wrap; gap: 24px; align-items: flex-start; padding-block: 20px 48px; }
.tool > .inputs { flex: 1 1 340px; max-width: 440px; min-width: 0; }
.tool > .results { flex: 999 1 520px; min-width: 0; display: flex; flex-direction: column; gap: 20px; }
@media (max-width: 860px) { .tool > .inputs { max-width: none; } }

.panel { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; display: flex; flex-direction: column; gap: 14px; min-width: 0; }
.panel h2 { font-size: 17px; font-weight: 600; }
.panel.strong { border: 1.5px solid var(--ink); }
.panel .sub { font-size: 14px; color: var(--muted); margin: 0; }

/* Forms */
.field { display: flex; flex-direction: column; gap: 6px; min-width: 0; }
.field > label, .label { font-size: 14px; font-weight: 500; color: var(--ink); }
.hint { font-size: 13px; color: var(--muted); }
.hint.mono { font-size: 12.5px; }
.row { display: flex; gap: 10px; flex-wrap: wrap; align-items: flex-end; }
.row > .field { flex: 1 1 120px; }
input[type="text"], input[type="number"], input[type="search"], select {
  height: 44px; padding: 0 12px; font: inherit; font-size: 16px; color: var(--ink);
  background: var(--surface); border: 1px solid var(--line-2); border-radius: 8px; min-width: 0; width: 100%;
}
input.num { font-family: var(--font-mono); }
input.big { height: 60px; font-size: 28px; border: 1.5px solid var(--ink); border-radius: 10px; padding: 0 16px; }
input:focus, select:focus { border-color: var(--accent); outline: 2px solid var(--accent); outline-offset: 0; }
input[aria-invalid="true"] { border-color: var(--bad); }
input[type="number"] { -moz-appearance: textfield; }
input[type="number"]::-webkit-inner-spin-button, input[type="number"]::-webkit-outer-spin-button { -webkit-appearance: none; margin: 0; }
.inline-unit { display: flex; gap: 8px; }
.inline-unit > input { flex: 1 1 auto; }
.inline-unit > select { flex: 0 0 auto; width: auto; }
fieldset { border: 0; margin: 0; padding: 0; min-width: 0; display: flex; flex-direction: column; gap: 12px; }
legend { padding: 0; margin-bottom: 12px; font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.08em; color: var(--muted); text-transform: uppercase; }

/* Pills (unit pickers, segmented controls) */
.pills { display: flex; flex-wrap: wrap; gap: 8px; }
.pill {
  min-height: 44px; padding: 0 16px; font: inherit; font-size: 15px; border-radius: 999px; cursor: pointer;
  background: var(--surface); color: var(--ink); border: 1px solid var(--line-2);
}
.pill:hover { border-color: var(--ink); }
.pill[aria-pressed="true"] { background: var(--ink); color: var(--paper); border-color: var(--ink); font-weight: 600; }
.pills.to .pill[aria-pressed="true"] { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); }
.seg { display: inline-flex; flex-wrap: wrap; gap: 4px; border-bottom: 1px solid var(--line); width: 100%; }
.seg button {
  min-height: 44px; padding: 0 16px; font: inherit; font-size: 15px; font-weight: 500; background: none; border: 0; cursor: pointer;
  color: var(--muted); border-bottom: 2.5px solid transparent; margin-bottom: -1px;
}
.seg button[aria-selected="true"] { color: var(--ink); font-weight: 600; border-bottom-color: var(--accent); }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 44px; padding: 0 16px;
  font: inherit; font-size: 15px; font-weight: 500; border-radius: 8px; cursor: pointer; text-decoration: none;
  background: var(--surface); color: var(--ink); border: 1px solid var(--line-2);
}
.btn:hover { border-color: var(--ink); color: var(--ink); }
.btn.primary { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); font-weight: 600; }
.btn.primary:hover { background: var(--accent-hover); border-color: var(--accent-hover); color: var(--accent-ink); }
.btn.dark { background: var(--ink); color: var(--paper); border-color: var(--ink); font-weight: 600; }
.btn.small { min-height: 36px; font-size: 13px; padding: 0 12px; }
.actions { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }

/* Result hero */
.answer { display: flex; flex-direction: column; gap: 8px; }
.answer .from { font-family: var(--font-mono); font-size: 18px; color: var(--muted); }
.answer .big { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 14px; }
.answer .val { font-family: var(--font-mono); font-variant-numeric: tabular-nums; font-size: clamp(40px, 6vw, 58px); font-weight: 500; letter-spacing: -0.02em; color: var(--accent); line-height: 1.1; overflow-wrap: anywhere; }
.answer .unit { font-size: 26px; font-weight: 600; }
.answer .rate { font-family: var(--font-mono); font-size: 13px; color: var(--muted); }

.mini-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 8px; }
.mini { padding: 10px 12px; background: var(--sunken); border-radius: 8px; display: flex; flex-direction: column; gap: 2px; min-width: 0; }
.mini b { font-family: var(--font-mono); font-variant-numeric: tabular-nums; font-size: 15px; font-weight: 500; overflow-wrap: anywhere; }
.mini span { font-size: 12.5px; color: var(--muted); }

.stats { display: grid; grid-template-columns: repeat(auto-fill, minmax(170px, 1fr)); gap: 12px; }
.stat { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; display: flex; flex-direction: column; gap: 4px; min-width: 0; }
.stat .k { font-size: 13px; color: var(--muted); }
.stat .v { font-family: var(--font-mono); font-variant-numeric: tabular-nums; font-size: 28px; font-weight: 500; line-height: 1.15; overflow-wrap: anywhere; }
.stat .s { font-size: 14px; color: var(--ink-2); }
.stat.hero { border: 1.5px solid var(--ink); }
.stat.hero .v { color: var(--accent); }

.basis { padding: 14px 16px; background: var(--sunken); border-radius: 8px; display: flex; flex-direction: column; gap: 4px; }
.basis p { margin: 0; font-family: var(--font-mono); font-size: 13px; color: var(--ink-2); line-height: 1.7; }

/* Status chips */
.check { display: flex; gap: 10px; align-items: flex-start; font-size: 15px; }
.chip { flex: none; font-size: 11.5px; font-weight: 600; letter-spacing: 0.03em; padding: 3px 7px; border-radius: 4px; line-height: 1.3; }
.chip.ok { background: var(--ok-bg); color: var(--ok); }
.chip.bad { background: var(--bad-bg); color: var(--bad); }
.chip.info { background: var(--sunken); color: var(--ink-2); }
.note { background: var(--warn-bg); border: 1px solid var(--warn-line); color: var(--warn); border-radius: var(--radius); padding: 14px 16px; font-size: 14px; line-height: 1.55; }
.error { color: var(--bad); font-size: 14px; }

/* Tables */
.table-box { overflow-x: auto; }
table.data { width: 100%; border-collapse: collapse; font-size: 15px; }
table.data th { text-align: left; font-size: 13px; font-weight: 600; color: var(--ink-2); background: var(--sunken); padding: 10px 14px; }
table.data td { padding: 10px 14px; border-top: 1px solid var(--line); }
table.data td.num { white-space: nowrap; }
table.data tr.hl td { background: var(--accent-soft); font-weight: 600; }

/* Drawings */
.sketch { width: 100%; max-width: 100%; height: auto; display: block; }
.sketch .edge { fill: var(--accent-soft); stroke: var(--accent); stroke-width: 2; }
.sketch .diag { stroke: var(--accent); stroke-width: 1.2; stroke-dasharray: 5 4; }
.sketch .lbl { fill: var(--ink); font-family: var(--font-mono); font-size: 12px; }
.sketch .lbl.m { fill: var(--muted); }
.sketch .pt { fill: var(--ink); }
.sketch .ink { stroke: var(--ink); fill: none; stroke-width: 1.5; }
.sketch .soft { fill: var(--sunken); stroke: var(--line-2); }

/* Footer */
.site-foot { border-top: 1px solid var(--line); background: var(--surface); margin-top: 24px; }
.site-foot .wrap { padding-block: 28px; display: flex; flex-wrap: wrap; gap: 20px; justify-content: space-between; font-size: 14px; color: var(--muted); }
.site-foot .wrap > div { flex: 1 1 380px; min-width: 0; }
.site-foot nav { display: flex; flex-wrap: wrap; gap: 18px; }
.site-foot nav a { color: var(--ink-2); }
.site-foot strong { color: var(--ink); }
.site-foot .wrap > div { display: flex; flex-direction: column; gap: 6px; }
.site-foot p { margin: 0; }
.site-foot .owner a { color: var(--ink-2); }
.site-nav a.by { color: var(--muted); font-weight: 400; font-size: 13px; }

/* Links to Arch21 Studios carry the parent brand's orange. Light: charcoal text, orange underline, orange highlight
   on hover (orange text on white is unreadable). Dark: orange text. */
a.a21, .site-nav a.a21, .site-foot .owner a.a21 {
  color: var(--arch21-link); text-decoration: underline; text-decoration-color: var(--arch21);
  text-decoration-thickness: 2px; text-underline-offset: 3px; border-radius: 2px;
}
a.a21:hover, .site-nav a.a21:hover, .site-foot .owner a.a21:hover { background: var(--arch21); color: var(--arch21-ink); text-decoration-color: var(--arch21); }
a.a21:focus-visible { outline-color: var(--arch21); }

/* Text pages (sources, disclaimer, privacy, contact) */
.prose { padding-block: 12px 48px; display: flex; flex-direction: column; gap: 20px; }
.prose > * { max-width: 780px; width: 100%; }
.prose p, .prose li { color: var(--ink-2); line-height: 1.65; }
.prose p { margin: 0; }
.prose ul { margin: 0; padding-left: 20px; display: flex; flex-direction: column; gap: 6px; }
.prose h2 { font-size: 20px; font-weight: 600; padding-top: 8px; }
.prose .panel { gap: 10px; }
.go-list { list-style: none; padding: 0 !important; margin: 0; display: flex; flex-direction: column; gap: 0 !important; }
.go-list li { display: grid; grid-template-columns: minmax(130px, 170px) 1fr; gap: 4px 16px; padding: 12px 0; border-top: 1px solid var(--line); }
.go-list li:first-child { border-top: 0; }
.go-list b { font-family: var(--font-mono); font-weight: 500; color: var(--ink); font-size: 14px; }
@media (max-width: 520px) { .go-list li { grid-template-columns: 1fr; } }
.contact-list { display: grid; grid-template-columns: max-content 1fr; gap: 10px 18px; align-items: baseline; margin: 0; }
.contact-list dt { font-size: 13px; color: var(--muted); }
.contact-list dd { margin: 0; color: var(--ink); overflow-wrap: anywhere; }
textarea { font: inherit; font-size: 16px; color: var(--ink); background: var(--surface); border: 1px solid var(--line-2); border-radius: 8px; padding: 10px 12px; width: 100%; min-height: 140px; resize: vertical; }
textarea:focus { border-color: var(--accent); outline: 2px solid var(--accent); outline-offset: 0; }

.toast { position: fixed; left: 50%; bottom: calc(24px + env(safe-area-inset-bottom, 0px)); transform: translateX(-50%); background: var(--ink); color: var(--paper); padding: 10px 16px; border-radius: 8px; font-size: 14px; z-index: 20; }

@media (prefers-reduced-motion: no-preference) {
  .pill, .btn { transition: border-color .12s, background-color .12s; }
}