/* Shear Wall Lab — technical drawing meets warm timber. */

:root {
  color-scheme: light;
  --paper: #f5f2ea;
  --paper-2: #efebe1;
  --ink: #1c1b18;
  --ink-2: #4b4943;
  --ink-3: #8b877d;
  --rule: #c9c3b5;
  --rule-strong: #1c1b18;
  --wood: #dcae6c;
  --wood-light: #ebc993;
  --wood-dark: #b88444;
  --wood-grain: #a8763a;
  --steel: #78838d;
  --steel-dark: #47515b;
  --steel-light: #b5bdc4;
  --accent: #1d5fc2;
  --accent-soft: #dbe5f4;
  --warn: #8a5a00;

  --f-label: 'Archivo Narrow', 'Arial Narrow', sans-serif;
  --f-ui: 'IBM Plex Sans', system-ui, sans-serif;
  --f-mono: 'IBM Plex Mono', ui-monospace, monospace;

  --gutter: 16px;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 14px/1.45 var(--f-ui);
}
a { color: var(--accent); }
button, input, select { font: inherit; color: inherit; }

/* ---- labels: condensed uppercase engineering lettering ---- */
.lbl, h2, h3, .tag, th {
  font-family: var(--f-label);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
}
.mono, .val, input[type=number] { font-family: var(--f-mono); }

/* ---- title block ---- */
.titleblock {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: stretch;
  border-bottom: 1px solid var(--rule-strong);
  background: var(--paper);
}
.titleblock .name {
  padding: 12px var(--gutter);
  border-right: 1px solid var(--rule-strong);
  display: flex; flex-direction: column; justify-content: center;
}
.titleblock .name b {
  font-family: var(--f-label);
  font-size: 22px; letter-spacing: 0.12em; text-transform: uppercase; font-weight: 700;
  line-height: 1;
}
.titleblock .name small { font-family: var(--f-mono); font-size: 11px; color: var(--ink-3); margin-top: 4px; }
.titleblock .intro { padding: 12px var(--gutter); align-self: center; color: var(--ink-2); max-width: 70ch; }
.titleblock nav { display: flex; border-left: 1px solid var(--rule-strong); }
.titleblock nav a {
  display: flex; align-items: center; padding: 0 18px;
  font-family: var(--f-label); text-transform: uppercase; letter-spacing: 0.08em; font-weight: 600;
  color: var(--ink); text-decoration: none; border-left: 1px solid var(--rule);
}
.titleblock nav a:first-child { border-left: 0; }
.titleblock nav a[aria-current=page] { background: var(--ink); color: var(--paper); }
.titleblock nav a:hover:not([aria-current]) { background: var(--paper-2); }
.titleblock nav a:focus-visible { outline: 2px solid var(--accent); outline-offset: -2px; }

/* ---- disclaimer: permanent ---- */
.disclaimer {
  position: sticky; bottom: 0; z-index: 5;
  border-top: 1px solid var(--rule-strong);
  background: var(--paper);
  padding: 6px var(--gutter);
  font-family: var(--f-label); text-transform: uppercase; letter-spacing: 0.06em;
  font-size: 12px; font-weight: 600;
  display: flex; gap: 10px; align-items: baseline;
}
.disclaimer .mark {
  border: 1px solid var(--ink); padding: 0 5px; font-size: 11px;
}

/* ---- layout ---- */
.sheet {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr) 360px;
  grid-template-areas:
    "inputs drawing results"
    "inputs curve results"
    "sweep sweep sweep";
  gap: 0;
  border-bottom: 1px solid var(--rule-strong);
}
.area-inputs { grid-area: inputs; border-right: 1px solid var(--rule-strong); }
.area-drawing { grid-area: drawing; border-bottom: 1px solid var(--rule-strong); }
.area-curve { grid-area: curve; }
.area-results { grid-area: results; border-left: 1px solid var(--rule-strong); }
.area-sweep { grid-area: sweep; border-top: 1px solid var(--rule-strong); }

.panel { min-width: 0; }
.panel > header {
  display: flex; align-items: baseline; justify-content: space-between; gap: 8px;
  padding: 8px var(--gutter);
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
}
.panel > header h2 { margin: 0; font-size: 13px; }
.panel > header .ref { font-family: var(--f-mono); font-size: 11px; color: var(--ink-3); }
.panel .body { padding: 12px var(--gutter); }

/* ---- inputs ---- */
.inputs { font-size: 13px; }
.inputs details { border-bottom: 1px solid var(--rule); }
.inputs summary {
  list-style: none; cursor: pointer;
  padding: 8px var(--gutter);
  display: flex; justify-content: space-between; align-items: baseline;
}
.inputs summary::-webkit-details-marker { display: none; }
.inputs summary .lbl { font-size: 12px; }
.inputs summary::after { content: '+'; font-family: var(--f-mono); color: var(--ink-3); }
.inputs details[open] summary::after { content: '−'; }
.inputs summary:focus-visible { outline: 2px solid var(--accent); outline-offset: -2px; }
.inputs .fields { padding: 0 var(--gutter) 10px; display: grid; gap: 6px; }
.field {
  display: grid; grid-template-columns: 1fr 92px 46px; align-items: center; gap: 6px;
}
.field > span:first-child { color: var(--ink-2); font-size: 12.5px; }
.field .sym { font-family: var(--f-mono); color: var(--ink-3); font-size: 11.5px; margin-left: 4px; }
.field .unit { font-family: var(--f-mono); font-size: 11px; color: var(--ink-3); }
.field input, .field select {
  width: 100%; min-width: 0;
  border: 1px solid var(--rule); border-radius: 0; background: #fbfaf6;
  padding: 3px 6px; font-size: 13px; text-align: right;
}
.field select { text-align: left; font-family: var(--f-ui); }
.field input:focus, .field select:focus, .row select:focus, .row input:focus {
  outline: none; border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent);
}
.field.check { grid-template-columns: 1fr auto; }
.field.check input { width: auto; }
.derived { font-family: var(--f-mono); font-size: 11.5px; color: var(--ink-3); }
.preset { padding: 10px var(--gutter); border-bottom: 1px solid var(--rule); display: grid; gap: 6px; }
.preset select { width: 100%; border: 1px solid var(--rule); background: #fbfaf6; padding: 4px 6px; border-radius: 0; }

.btn {
  border: 1px solid var(--ink); background: var(--paper); border-radius: 0;
  padding: 4px 10px; cursor: pointer;
  font-family: var(--f-label); text-transform: uppercase; letter-spacing: 0.06em; font-weight: 600; font-size: 12px;
}
.btn:hover { background: var(--ink); color: var(--paper); }
.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
.btn.small { padding: 2px 8px; font-size: 11px; }

/* ---- drawing ---- */
.drawing-wrap { position: relative; }
#wall { display: block; width: 100%; height: auto; max-height: 62vh; background: var(--paper); }
.controls {
  display: grid; grid-template-columns: auto 1fr auto; gap: 10px 14px; align-items: center;
  padding: 10px var(--gutter);
  border-top: 1px solid var(--rule);
}
.controls .readout { font-family: var(--f-mono); font-size: 12.5px; white-space: nowrap; }
.controls .toggles { grid-column: 1 / -1; display: flex; flex-wrap: wrap; gap: 6px 18px; font-size: 12.5px; color: var(--ink-2); }
.controls label { display: inline-flex; gap: 6px; align-items: center; cursor: pointer; }

input[type=range] {
  -webkit-appearance: none; appearance: none; width: 100%; background: transparent; height: 22px; margin: 0;
}
input[type=range]::-webkit-slider-runnable-track { height: 1px; background: var(--ink); }
input[type=range]::-moz-range-track { height: 1px; background: var(--ink); }
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 12px; height: 18px; margin-top: -9px;
  background: var(--accent); border: 0; border-radius: 0;
}
input[type=range]::-moz-range-thumb { width: 12px; height: 18px; background: var(--accent); border: 0; border-radius: 0; }
input[type=range]:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
input[type=checkbox] { accent-color: var(--accent); margin: 0; }

/* ---- results ---- */
.kv { display: grid; grid-template-columns: 1fr auto; gap: 3px 10px; margin: 0; font-size: 13px; }
.kv dt { color: var(--ink-2); }
.kv dd { margin: 0; text-align: right; font-family: var(--f-mono); }
.headline { display: grid; gap: 2px; padding-bottom: 10px; margin-bottom: 10px; border-bottom: 1px solid var(--rule); }
.headline .lbl { font-size: 11.5px; color: var(--ink-3); }
.headline .big { font-family: var(--f-mono); font-size: 30px; line-height: 1.1; }
.headline .big small { font-size: 14px; color: var(--ink-3); margin-left: 4px; }
.headline .sub { font-size: 13px; }
.behaviour { font-size: 13.5px; margin-bottom: 10px; }
.section-title { font-family: var(--f-label); text-transform: uppercase; letter-spacing: 0.06em; font-weight: 600;
  font-size: 12px; color: var(--ink); margin: 14px 0 6px; padding-top: 10px; border-top: 1px solid var(--rule);
  display: flex; justify-content: space-between; align-items: baseline; }
.section-title .mono { text-transform: none; letter-spacing: 0; font-weight: 400; color: var(--ink-3); font-size: 11.5px; }

table.util { width: 100%; border-collapse: collapse; font-size: 12.5px; }
table.util th { font-size: 11px; color: var(--ink-3); text-align: left; font-weight: 600; padding: 2px 0; border-bottom: 1px solid var(--rule); }
table.util th.r, table.util td.r { text-align: right; }
table.util td { padding: 4px 0; border-bottom: 1px solid var(--paper-2); vertical-align: middle; }
table.util td.val { font-family: var(--f-mono); }
.ubar { position: relative; height: 6px; border: 1px solid var(--ink-3); width: 70px; display: inline-block; vertical-align: middle; margin-left: 6px; }
.ubar i { position: absolute; left: 0; top: 0; bottom: 0; background: var(--ink-2); }
.ubar.hot i { background: var(--accent); }

.notes { margin: 10px 0 0; padding: 0; list-style: none; font-size: 12.5px; color: var(--ink-2); }
.notes li { border-left: 2px solid var(--ink); padding: 2px 0 2px 8px; margin-bottom: 6px; }

/* ---- charts ---- */
svg.chart { display: block; width: 100%; height: auto; }
.chart text { font-family: var(--f-mono); font-size: 10.5px; fill: var(--ink-2); }
.chart .axis-label { font-family: var(--f-label); text-transform: uppercase; letter-spacing: 0.06em; font-weight: 600; fill: var(--ink); font-size: 11px; }
.chart .grid { stroke: var(--rule); stroke-width: 1; shape-rendering: crispEdges; }
.chart .axis { stroke: var(--ink); stroke-width: 1; shape-rendering: crispEdges; }
.chart .series { fill: none; stroke: var(--accent); stroke-width: 1.75; stroke-linejoin: round; }
.chart .series.alt { stroke: var(--ink-2); stroke-dasharray: 4 3; stroke-width: 1.25; }
.chart .key { fill: var(--paper); stroke: var(--ink); stroke-width: 1; }
.chart .now { fill: var(--accent); }
.chart .guide { stroke: var(--accent); stroke-width: 1; stroke-dasharray: 2 3; }
.chart .ref { stroke: var(--ink-3); stroke-dasharray: 5 4; stroke-width: 1; }
.chart .bar { fill: var(--accent); }
.chart .bar-track { fill: none; stroke: var(--rule); }

.curve-actions, .sweep-actions { display: flex; gap: 8px; flex-wrap: wrap; }

/* ---- sweep ---- */
.sweep-grid { display: grid; grid-template-columns: 300px 1fr 1fr; }
.sweep-grid > div { min-width: 0; }
.sweep-form { padding: 12px var(--gutter); border-right: 1px solid var(--rule); display: grid; gap: 8px; align-content: start; }
.row { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 6px; }
.row label { display: grid; gap: 2px; font-size: 11.5px; color: var(--ink-3); }
.row input, .row select, .sweep-form select {
  width: 100%; border: 1px solid var(--rule); background: #fbfaf6; padding: 3px 6px; border-radius: 0; font-family: var(--f-mono); font-size: 13px; color: var(--ink);
}
.sweep-form select { font-family: var(--f-ui); }
.sweep-chart { padding: 8px var(--gutter) 12px; }
.sweep-chart + .sweep-chart { border-left: 1px solid var(--rule); }
.sweep-summary { font-size: 12px; color: var(--ink-2); }

/* ---- How it works page ---- */
.doc { max-width: 760px; padding: 24px var(--gutter) 48px; margin: 0 auto; }
.doc h1 { font-family: var(--f-label); text-transform: uppercase; letter-spacing: 0.08em; font-size: 26px; margin: 0 0 6px; }
.doc h2 { font-size: 14px; margin: 28px 0 8px; padding-top: 10px; border-top: 1px solid var(--rule-strong); }
.doc p, .doc li { color: var(--ink-2); }
.doc figure { margin: 14px 0; border: 1px solid var(--rule); padding: 10px; background: var(--paper); }
.doc figcaption { font-family: var(--f-label); text-transform: uppercase; letter-spacing: 0.06em; font-size: 11.5px; color: var(--ink-3); margin-top: 6px; }
.doc code { font-family: var(--f-mono); font-size: 12.5px; }
.doc ol.refs li { margin-bottom: 6px; font-size: 13px; }

/* ---- responsive ---- */
@media (max-width: 1180px) {
  .sheet {
    grid-template-columns: 290px minmax(0, 1fr);
    grid-template-areas:
      "inputs drawing"
      "inputs results"
      "curve curve"
      "sweep sweep";
  }
  .area-results { border-left: 0; border-bottom: 1px solid var(--rule-strong); }
  .area-drawing { border-bottom: 1px solid var(--rule-strong); }
  .sweep-grid { grid-template-columns: 1fr 1fr; }
  .sweep-form { grid-column: 1 / -1; border-right: 0; border-bottom: 1px solid var(--rule); }
  .sweep-chart:nth-child(2) { border-left: 0; }
}
@media (max-width: 760px) {
  body { font-size: 14px; }
  .titleblock { grid-template-columns: 1fr; }
  .titleblock .name { border-right: 0; border-bottom: 1px solid var(--rule); }
  .titleblock .intro { padding-top: 8px; padding-bottom: 8px; font-size: 13px; }
  .titleblock nav { border-left: 0; border-top: 1px solid var(--rule-strong); }
  .titleblock nav a { flex: 1; justify-content: center; padding: 10px 6px; }
  .sheet {
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas: "drawing" "results" "curve" "inputs" "sweep";
  }
  .area-inputs { border-right: 0; border-bottom: 1px solid var(--rule-strong); }
  .area-curve { border-bottom: 1px solid var(--rule-strong); }
  .controls { grid-template-columns: auto 1fr; }
  .controls .readout { grid-column: 1 / -1; white-space: normal; }
  #wall { max-height: none; }
  .sweep-grid { grid-template-columns: 1fr; }
  .sweep-chart + .sweep-chart { border-left: 0; border-top: 1px solid var(--rule); }
  .field { grid-template-columns: 1fr 100px 44px; }
  .disclaimer { font-size: 11px; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; scroll-behavior: auto !important; }
}