/* ---------------------------------------------------------------------------
   Statbench — the page is ruled graph paper, the content sits on it as plates.
   Observed nodes are shaded, the way they are in any PGM diagram; the strip
   under the masthead is your own practice rendered as a distribution.
--------------------------------------------------------------------------- */

:root {
  --paper:       #e8edef;
  --rule:        #d3dee3;
  --rule-strong: #b0c1c9;
  --plate:       #fbfcfd;
  --ink:         #131c22;
  --ink-2:       #435660;
  --ink-3:       #74888f;
  --accent:      #8c2f39;
  --accent-soft: #f0e0e1;
  --ok:          #1b6b5f;
  --ok-soft:     #dceae6;
  --no:          #b4531e;
  --no-soft:     #f5e4d8;
  --cell:        22px;
  --shadow:      3px 3px 0 rgba(19, 28, 34, 0.09);

  --sans: "IBM Plex Sans", ui-sans-serif, system-ui, sans-serif;
  --display: "Space Grotesk", "IBM Plex Sans", ui-sans-serif, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", monospace;
}

* { box-sizing: border-box; }

/* The `hidden` attribute is enforced only by the browser's own stylesheet, and
   author rules beat user-agent rules in the cascade whatever their specificity.
   Several classes below set `display`, and each of them would otherwise
   silently un-hide its element while `node.hidden = true` appeared to work.
   This has to outrank all of them, so it is deliberately !important. */
[hidden] { display: none !important; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.6;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    linear-gradient(to right, var(--rule) 1px, transparent 1px),
    linear-gradient(to bottom, var(--rule) 1px, transparent 1px);
  background-size: var(--cell) var(--cell);
}

h1, h2, h3 { font-family: var(--display); font-weight: 700; letter-spacing: -0.012em; margin: 0; }
p { margin: 0; }

/* --- masthead ----------------------------------------------------------- */

.masthead {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  padding: 22px 28px 14px;
  border-bottom: 1px solid var(--rule-strong);
  background: rgba(232, 237, 239, 0.86);
}

.brand { display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; }

.brand-mark {
  width: 13px; height: 13px;
  align-self: center;
  background: var(--accent);
  box-shadow: 17px 0 0 var(--ok);
  margin-right: 17px;
}

.brand-name { font-family: var(--display); font-weight: 700; font-size: 19px; }

.brand-sub {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--ink-3);
  letter-spacing: 0.02em;
}

.account { display: flex; align-items: baseline; gap: 14px; }
.account-email { font-family: var(--mono); font-size: 12px; color: var(--ink-2); }

/* --- the mass strip ----------------------------------------------------- */

.massbar { padding: 16px 28px 0; }

.massbar-rail {
  display: flex;
  height: 30px;
  border: 1px solid var(--ink);
  background: var(--plate);
  overflow: hidden;
}

.mass-seg {
  position: relative;
  min-width: 0;
  border-right: 1px solid var(--plate);
  background: var(--accent);
  transition: width 420ms cubic-bezier(0.2, 0.7, 0.3, 1);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.mass-seg:last-child { border-right: 0; }
.mass-seg[data-mastered="1"] { background: var(--ok); }

.mass-seg span {
  font-family: var(--mono);
  font-size: 10px;
  color: rgba(255, 255, 255, 0.92);
  white-space: nowrap;
  padding: 0 4px;
}

.massbar-rail.is-empty {
  background-image: repeating-linear-gradient(
    135deg, transparent 0 6px, var(--rule) 6px 7px
  );
}

.massbar-caption {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--ink-3);
  margin-top: 6px;
}

/* --- layout ------------------------------------------------------------- */

main { padding: 22px 28px 64px; }

.workspace {
  display: grid;
  grid-template-columns: minmax(280px, 340px) minmax(0, 1fr);
  gap: 22px;
  align-items: start;
  max-width: 1180px;
}

.plate {
  background: var(--plate);
  border: 1px solid var(--ink);
  box-shadow: var(--shadow);
  padding: 22px;
}

/* --- gate --------------------------------------------------------------- */

.gate { display: flex; justify-content: center; padding-top: 24px; }
.gate-plate { max-width: 500px; width: 100%; }
.gate-title { font-size: 30px; margin-bottom: 10px; }
.gate-lede { color: var(--ink-2); margin-bottom: 22px; }

.field { display: flex; flex-direction: column; gap: 8px; margin-bottom: 8px; }
.field label { font-family: var(--mono); font-size: 11px; text-transform: uppercase; letter-spacing: 0.08em; color: var(--ink-3); }

input[type="email"], input[type="text"] {
  font-family: var(--mono);
  font-size: 16px;
  padding: 11px 12px;
  border: 1px solid var(--rule-strong);
  background: #fff;
  color: var(--ink);
  width: 100%;
}

input:focus-visible, button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

#code { letter-spacing: 0.4em; font-size: 20px; }

.btn {
  font-family: var(--sans);
  font-weight: 600;
  font-size: 14.5px;
  padding: 11px 20px;
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--plate);
  cursor: pointer;
  align-self: flex-start;
  transition: transform 90ms ease, box-shadow 90ms ease;
}

.btn:hover { box-shadow: var(--shadow); transform: translate(-1px, -1px); }
.btn:active { transform: translate(1px, 1px); box-shadow: none; }
.btn[disabled] { opacity: 0.45; cursor: default; transform: none; box-shadow: none; }

.btn-quiet { background: transparent; color: var(--ink-2); border-color: var(--rule-strong); }

.link-btn {
  font-family: var(--sans);
  font-size: 13px;
  background: none;
  border: 0;
  padding: 0;
  color: var(--ink-2);
  text-decoration: underline;
  text-underline-offset: 3px;
  cursor: pointer;
  align-self: flex-start;
}

.notice {
  margin-top: 14px;
  padding: 10px 12px;
  font-size: 13.5px;
  border-left: 3px solid var(--no);
  background: var(--no-soft);
  color: var(--ink);
}

.notice[data-tone="ok"] { border-left-color: var(--ok); background: var(--ok-soft); }

/* --- ledger ------------------------------------------------------------- */

.ledger {
  background: var(--plate);
  border: 1px solid var(--ink);
  box-shadow: var(--shadow);
  padding: 16px 0 14px;
}

.ledger-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 13px;
  font-family: var(--mono);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: var(--ink-3);
  padding: 0 18px 12px;
  border-bottom: 1px solid var(--rule);
}

.ledger-total { color: var(--ink-2); letter-spacing: 0.02em; text-transform: none; }

.ledger-list { list-style: none; margin: 0; padding: 0; }

.topic-row {
  display: block;
  width: 100%;
  text-align: left;
  background: none;
  border: 0;
  border-bottom: 1px solid var(--rule);
  border-left: 3px solid transparent;
  padding: 12px 18px;
  cursor: pointer;
  font-family: inherit;
  color: inherit;
}

.topic-row:hover { background: #f2f6f7; }
.topic-row[aria-current="true"] { border-left-color: var(--accent); background: #f2f6f7; }

.topic-row-top { display: flex; justify-content: space-between; align-items: baseline; gap: 10px; }

.topic-name { font-family: var(--display); font-weight: 500; font-size: 15px; }

.topic-level {
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--ink-3);
  white-space: nowrap;
}

.topic-blurb { font-size: 12.5px; color: var(--ink-3); line-height: 1.45; margin-top: 2px; }

.cells { display: flex; gap: 3px; margin-top: 8px; }

.cells i {
  width: 11px; height: 11px;
  border: 1px solid var(--rule-strong);
  background: transparent;
}

.cells i[data-on="1"] { background: var(--accent); border-color: var(--accent); }
.cells[data-mastered="1"] i[data-on="1"] { background: var(--ok); border-color: var(--ok); }

.ledger-key {
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--ink-3);
  padding: 12px 18px 0;
  line-height: 1.5;
}

/* --- bench -------------------------------------------------------------- */

.empty h2 { font-size: 20px; margin-bottom: 8px; }
.empty p { color: var(--ink-2); max-width: 52ch; }

.drill-head { display: flex; justify-content: space-between; align-items: baseline; gap: 14px; }
.drill-title { font-size: 21px; }

.level-badge {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  padding: 3px 8px;
  border: 1px solid var(--rule-strong);
  color: var(--ink-2);
  white-space: nowrap;
}

.drill-note {
  font-size: 13.5px;
  color: var(--ink-2);
  border-left: 3px solid var(--rule-strong);
  padding-left: 12px;
  margin: 12px 0 20px;
  max-width: 68ch;
}

.drill-body { border-top: 1px solid var(--rule); padding-top: 18px; }

.prompt { max-width: 66ch; }

.given {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 10px;
}

.given li {
  font-family: var(--mono);
  font-size: 12.5px;
  background: var(--paper);
  border: 1px solid var(--rule-strong);
  padding: 3px 8px;
}

.figures { display: flex; flex-wrap: wrap; gap: 20px; margin: 18px 0 4px; }

.figure { border: 1px solid var(--rule-strong); background: #fff; padding: 12px 14px; }

.figure-cap {
  font-family: var(--mono);
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--ink-3);
  margin-bottom: 8px;
}

table.ct { border-collapse: collapse; font-family: var(--mono); font-size: 13.5px; }
table.ct th, table.ct td { border: 1px solid var(--rule-strong); padding: 5px 11px; text-align: right; }
table.ct thead th { background: var(--paper); font-weight: 500; color: var(--ink-2); }
table.ct tbody th { background: var(--paper); font-weight: 500; text-align: left; color: var(--ink-2); }
table.ct th.corner { background: transparent; border-color: var(--rule-strong); color: var(--ink-3); text-align: left; }

.edgelist {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--ink-2);
  margin-top: 8px;
  letter-spacing: 0.02em;
}

.ask { display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; margin-top: 22px; }

.ask-label {
  font-family: var(--mono);
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-3);
}

.ask-expr {
  font-family: var(--mono);
  font-size: 17px;
  font-weight: 500;
  background: var(--accent-soft);
  border-bottom: 2px solid var(--accent);
  padding: 2px 8px;
}

.answer { margin-top: 16px; }

.numeric-input { max-width: 260px; }

.input-hint { font-family: var(--mono); font-size: 11px; color: var(--ink-3); margin-top: 6px; }

.options { display: flex; flex-direction: column; gap: 8px; max-width: 60ch; }

.option {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  text-align: left;
  font-family: var(--sans);
  font-size: 14.5px;
  padding: 10px 13px;
  border: 1px solid var(--rule-strong);
  background: #fff;
  cursor: pointer;
  color: inherit;
}

.option:hover { border-color: var(--ink-2); }
.option[aria-pressed="true"] { border-color: var(--accent); background: var(--accent-soft); }

.option-key {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--ink-3);
  border: 1px solid var(--rule-strong);
  padding: 0 5px;
  flex: none;
  margin-top: 2px;
}

.option[aria-pressed="true"] .option-key { color: var(--accent); border-color: var(--accent); }

.chips { display: flex; flex-wrap: wrap; gap: 8px; }

.chip {
  font-family: var(--mono);
  font-size: 15px;
  min-width: 44px;
  padding: 8px 12px;
  border: 1px solid var(--rule-strong);
  background: #fff;
  cursor: pointer;
  color: inherit;
}

.chip[aria-pressed="true"] { border-color: var(--accent); background: var(--accent-soft); color: var(--accent); }

.controls { display: flex; gap: 10px; margin-top: 22px; flex-wrap: wrap; }

/* --- verdict ------------------------------------------------------------ */

.verdict { margin-top: 22px; border-top: 1px solid var(--rule); padding-top: 18px; }

.verdict-line { display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; font-family: var(--mono); font-size: 14px; }

.verdict-tag {
  font-family: var(--sans);
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  padding: 3px 9px;
  color: #fff;
  background: var(--no);
}

.verdict[data-correct="1"] .verdict-tag { background: var(--ok); }

.verdict-explain { margin: 14px 0 20px; max-width: 70ch; color: var(--ink-2); }

.loading { text-align: center; padding: 60px 20px; font-family: var(--mono); color: var(--ink-3); }

/* --- graph -------------------------------------------------------------- */

.dag { display: block; }
.dag .edge { stroke: var(--ink-2); stroke-width: 1.4; }
.dag .node { fill: #fff; stroke: var(--ink); stroke-width: 1.4; }
.dag .node[data-role="primary"] { stroke: var(--accent); stroke-width: 2.4; }
.dag .node[data-role="evidence"] { fill: var(--ink); stroke: var(--ink); }
.dag .label { font-family: var(--mono); font-size: 13px; fill: var(--ink); }
.dag .label[data-role="evidence"] { fill: #fff; }

/* --- responsive --------------------------------------------------------- */

@media (max-width: 900px) {
  .masthead, .massbar, main { padding-left: 16px; padding-right: 16px; }
  .workspace { grid-template-columns: 1fr; }
  .bench { order: 1; }
  .ledger { order: 2; }
  .plate { padding: 18px 16px; }
  .brand-sub { display: none; }
}

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