/* ============================================================
   sitemath — concrete grey + safety yellow. The tape blade.
   Light (cast concrete) default; dark (shuttering) scheme.
   System sans only; tabular numerals on every figure.
   ============================================================ */

:root {
  --ground:  #E9EAE6;   /* cast concrete */
  --card:    #F5F6F2;   /* form panel */
  --card2:   #EEEFEA;
  --ink:     #1B1D1E;   /* carbon */
  --muted:   #5C6266;   /* rebar grey, darkened for AA small text */
  --line:    #C9CCC5;   /* decorative hairline (card edges, row separators) */
  --control-line: #767C80; /* rebar grey — interactive control boundary, AA 1.4.11 (≥3:1) */
  --tape:    #F7C600;   /* safety yellow — tape blade, buy figures, CTAs only */
  --tape-ink:#1B1D1E;
  --beta:    #8A4B00;   /* beta flag text (AA on card) */
  --beta-bg: #F6E3C8;
  --ok:      #2E6B45;
  --focus:   #1B5FAA;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Noto Sans", Helvetica, Arial, sans-serif;
  --radius: 10px;
  --radius-sm: 6px;
  --wrap: 1080px;
}

[data-theme="dark"] {
  --ground:  #17191B;   /* shuttering */
  --card:    #24272A;   /* cement */
  --card2:   #1D2023;
  --ink:     #E5E7E2;   /* pale concrete */
  --muted:   #A6ADB0;
  --line:    #3A3E42;
  --control-line: #767C80; /* rebar grey — interactive control boundary, AA 1.4.11 (≥3:1) */
  --tape:    #FFD23F;   /* high-vis */
  --tape-ink:#1B1D1E;
  --beta:    #F2C27E;
  --beta-bg: #3A2E1C;
  --ok:      #7FC79A;
  --focus:   #7FB4EE;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--ground);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { margin: 0 0 .35em; font-weight: 800; letter-spacing: -0.02em; line-height: 1.12; }
h1 { font-size: 1.7rem; }
h2 { font-size: 1.25rem; }
h3 { font-size: 1.02rem; }
p  { margin: .3em 0; }
a  { color: inherit; }
code { font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace; font-size: .92em; }

.num, output, td.qty, .figure {
  font-variant-numeric: tabular-nums;
}

/* skip link */
.skip-link {
  position: absolute; left: -9999px; top: 0;
  background: var(--tape); color: var(--tape-ink);
  padding: .6em 1em; font-weight: 700; z-index: 99; border-radius: 0 0 var(--radius-sm) 0;
}
.skip-link:focus { left: 0; }

/* ---- the tape blade motif ---- */
.tape-blade {
  height: 16px;
  background:
    repeating-linear-gradient(90deg,
      transparent 0 2px, var(--tape-ink) 2px 3.5px, transparent 3.5px 24px),
    repeating-linear-gradient(90deg,
      transparent 0 2px, var(--tape-ink) 2px 3px, transparent 3px 96px),
    var(--tape);
  background-size: 24px 7px, 96px 12px, auto;
  background-repeat: repeat-x;
  background-position: left top, left top, 0 0;
  border-radius: 2px;
  position: relative;
}
.tape-blade::after {           /* end hook */
  content: "";
  position: absolute; right: -4px; top: -3px;
  width: 6px; height: 22px;
  background: var(--tape-ink);
  border-radius: 1px;
}
.tick-run {                     /* short graduation run = section divider */
  height: 10px; width: 88px;
  background: repeating-linear-gradient(90deg,
    var(--muted) 0 2px, transparent 2px 11px);
  opacity: .75;
  margin: .1rem 0 .8rem;
}

/* layout */
header.site, main, footer.site {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 20px;
}
header.site {
  display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
  padding-top: 22px; padding-bottom: 6px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand svg { display: block; }
.wordmark { font-size: 1.35rem; font-weight: 800; letter-spacing: -0.02em; }
.head-actions { margin-left: auto; display: flex; gap: 8px; flex-wrap: wrap; }

.lede { color: var(--muted); max-width: 62ch; }

.banner {
  display: flex; gap: 10px; align-items: baseline;
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 5px solid var(--tape);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  margin: 14px 0 4px;
  font-size: .93rem;
}
.banner strong { white-space: nowrap; }

section.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 20px 20px;
  margin: 18px 0;
}

/* forms */
label { font-size: .86rem; font-weight: 600; display: block; margin-bottom: 2px; }
input[type="number"], input[type="text"], select {
  font: inherit; color: var(--ink);
  background: var(--card2);
  border: 1px solid var(--control-line);
  border-radius: var(--radius-sm);
  padding: 6px 8px;
  width: 100%;
  font-variant-numeric: tabular-nums;
}
input:focus-visible, select:focus-visible, button:focus-visible,
a:focus-visible, [tabindex]:focus-visible, summary:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 1px;
}
fieldset { border: 1px solid var(--line); border-radius: var(--radius-sm); margin: 0; }
legend { font-size: .85rem; font-weight: 700; padding: 0 6px; }

button {
  font: inherit; font-weight: 700;
  color: var(--ink);
  background: var(--card2);
  border: 1px solid var(--control-line);
  border-radius: var(--radius-sm);
  padding: 7px 14px;
  cursor: pointer;
}
button:hover { border-color: var(--muted); }
button.cta {
  background: var(--tape); color: var(--tape-ink); border-color: var(--tape-ink);
}
button.small { padding: 3px 9px; font-size: .84rem; font-weight: 600; }
button.danger { color: #A32014; }
[data-theme="dark"] button.danger { color: #FF9C8F; }

.grid { display: grid; gap: 10px 14px; }
.grid.cols-3 { grid-template-columns: repeat(3, minmax(0,1fr)); }
.grid.cols-4 { grid-template-columns: repeat(4, minmax(0,1fr)); }
.grid.cols-6 { grid-template-columns: repeat(6, minmax(0,1fr)); }
@media (max-width: 760px) {
  .grid.cols-3, .grid.cols-4, .grid.cols-6 { grid-template-columns: repeat(2, minmax(0,1fr)); }
}

/* rooms table */
.room-row {
  display: grid;
  grid-template-columns: minmax(90px,1.4fr) repeat(3, minmax(64px,.8fr)) repeat(2, minmax(58px,.7fr)) auto auto;
  gap: 8px; align-items: end;
  padding: 10px 0;
  border-bottom: 1px dashed var(--line);
}
@media (max-width: 760px) { .room-row { grid-template-columns: repeat(4, minmax(0,1fr)); } }
.room-row .ceil { display: flex; align-items: center; gap: 6px; padding-bottom: 8px; font-size: .86rem; font-weight: 600; }

.readout {
  margin-top: 14px;
  padding: 12px 0 4px;
}
.readout .big {
  font-size: 1.9rem; font-weight: 800; letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}
.readout .sub { color: var(--muted); font-size: .92rem; }

/* result cards */
table { border-collapse: collapse; width: 100%; font-size: .94rem; }
th, td { text-align: left; padding: 7px 10px 7px 0; border-bottom: 1px solid var(--line); vertical-align: top; }
th { font-size: .8rem; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); }
td.qty, th.qty { text-align: right; padding-right: 0; white-space: nowrap; }
.buy {
  font-weight: 800;
  background: var(--tape); color: var(--tape-ink);
  border: 1px solid var(--tape-ink);
  padding: 1px 7px; border-radius: 4px; white-space: nowrap;
}
.range { white-space: nowrap; }

.chip {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: .8rem; font-weight: 600;
  border: 1px solid var(--control-line);
  background: var(--card2);
  border-radius: 999px;
  padding: 2px 10px;
  cursor: pointer;
}
.chip.beta { border-color: var(--beta); color: var(--beta); background: var(--beta-bg); }
.chip.yours { border-color: var(--ok); color: var(--ok); }
.chip .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--muted); }
.chip.beta .dot { background: var(--beta); }
.chip.yours .dot { background: var(--ok); }

.badge-beta {
  font-size: .74rem; font-weight: 800; letter-spacing: .06em;
  color: var(--beta); background: var(--beta-bg);
  border: 1px solid var(--beta);
  padding: 1px 7px; border-radius: 4px;
  text-transform: uppercase;
}
.badge-yours {
  font-size: .74rem; font-weight: 800; letter-spacing: .06em;
  color: var(--ok); border: 1px solid var(--ok);
  padding: 1px 7px; border-radius: 4px;
  text-transform: uppercase;
}

/* coefficient cards */
.coeff-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--card2);
  padding: 12px 14px;
  margin: 10px 0;
}
.coeff-card .band { font-weight: 800; font-variant-numeric: tabular-nums; }
.coeff-card blockquote {
  margin: 6px 0; padding: 4px 10px;
  border-left: 3px solid var(--tape);
  color: var(--muted); font-size: .9rem;
}
.coeff-card .meta { font-size: .84rem; color: var(--muted); }
.coeff-card .meta a { word-break: break-all; }

dialog {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--card);
  color: var(--ink);
  max-width: 34rem;
  padding: 18px 20px;
}
dialog::backdrop { background: rgba(20,22,24,.55); }

details { margin: 8px 0; }
summary { cursor: pointer; font-weight: 700; }

ul.limits { padding-left: 1.2em; }
ul.limits li { margin: .45em 0; }

footer.site {
  border-top: 1px solid var(--line);
  margin-top: 30px;
  padding-top: 16px; padding-bottom: 34px;
  font-size: .88rem; color: var(--muted);
}

/* utility classes (CSP forbids inline style attributes) */
.u-wauto { width: auto; }
.m0 { margin: 0; }
.mb8 { margin-bottom: 8px; }
.mb10 { margin-bottom: 10px; }
.mb12 { margin-bottom: 12px; }
.mt4 { margin-top: 4px; }
.mt8 { margin-top: 8px; }
.gap6 { gap: 6px; }
.self-end { align-self: end; }
.w220 { max-width: 220px; }
.w280 { max-width: 280px; }
.w340 { max-width: 340px; }
.w45 { width: 4.5em; }
.muted { color: var(--muted); }
.note { color: var(--muted); font-size: .9rem; }
.note-sm { color: var(--muted); font-size: .88rem; }
.span2 { grid-column: span 2; align-self: end; }
@media (max-width: 760px) { .span2 { grid-column: span 1; } }
.scroll-x { overflow-x: auto; }
.btnrow { margin-top: 14px; display: flex; gap: 10px; flex-wrap: wrap; }
.row4 { display: flex; gap: 4px; }
.inline-check { display: inline-flex; gap: 5px; align-items: center; margin-right: 10px; font-weight: 600; }
.choice-row { display: flex; gap: 6px; align-items: center; flex-wrap: wrap; }
.choice-row label { font-size: .92rem; font-weight: 600; }
.room-actions { display: flex; gap: 6px; align-items: end; }
.room-net { font-size: .86rem; color: var(--muted); align-self: center; }
.layer-on { display: flex; gap: 6px; align-items: center; margin: 0; font-size: .98rem; }
.coeff-head { display: flex; gap: 8px; flex-wrap: wrap; align-items: baseline; }
.dlg-actions { margin-top: 12px; display: flex; gap: 8px; justify-content: flex-end; }
dialog blockquote {
  border-left: 3px solid var(--tape);
  padding: 4px 10px; margin: 6px 0;
  color: var(--muted); font-size: .9rem;
}
dialog .meta { font-size: .86rem; color: var(--muted); }
dialog .meta a { word-break: break-all; }

.visually-hidden {
  position: absolute; width: 1px; height: 1px;
  margin: -1px; padding: 0; overflow: hidden;
  clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

@media (prefers-reduced-motion: no-preference) {
  button, .chip { transition: border-color .15s ease, background .15s ease; }
}

/* ---- print: the A4 site list ---- */
@media print {
  body { background: #fff; color: #000; font-size: 12px; }
  header .head-actions, .banner, button, .no-print, nav, .tick-run { display: none !important; }
  section.card { border: none; padding: 0; margin: 12px 0; break-inside: avoid; }
  .tape-blade { background: #ddd; height: 6px; }
  .tape-blade::after { display: none; }
  .buy { background: none; border: 2px solid #000; }
  a::after { content: ""; }
  .print-only { display: block !important; }
}
.print-only { display: none; }