/* Formula Builder. The look follows the style pack's palette (mustard bar,
   cream canvas, plum ink) in a flat icon style: thick rounded ink outlines,
   flat fills, no gradients or shadows. Concept colours come from the core. */
:root {
  --ink: #3b2340;
  --bar: #efc46a;
  --bar-hi: #f5da92;
  --paper: #f6e7c4;
  --canvas: #fff6e0;
  --panel: #fffaf0;
  --muted: #6d5a68;
  --line: #3b2340;
  --soft: #e3d3b4;
  --teal: #4fa3a0;
  --sage: #6fa77a;
  --error: #b03a2e;
  --focus: #1d6fa3;
  --body: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --radius: 10px;
  --stroke: 2px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --ink: #f3e8dc; --paper: #2b2030; --panel: #231a27; --muted: #c1afba; --soft: #4a3a4f;
    --line: #f3e8dc; --bar: #c99a3e; --bar-hi: #4a3a22; --error: #ef9a88; --focus: #86b8e4;
  }
  body { background: #1b141e; }
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 15px/1.5 var(--body);
}
button, select, input, textarea { font: inherit; color: inherit; }
button, .button, select {
  border: var(--stroke) solid var(--line);
  background: var(--panel);
  border-radius: 7px;
  padding: 4px 11px;
  cursor: pointer;
  font-weight: 600;
}
button:hover, .button:hover { background: var(--bar-hi); }
button.primary { background: var(--teal); color: #fff; }
button.embed { background: var(--sage); color: #fff; }
button:disabled { opacity: .45; cursor: default; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }
.small { font-size: 13px; color: var(--muted); }
.help { font-size: 13px; color: var(--muted); margin: 0; }
.head { font-weight: 800; font-size: 15px; margin: 0; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
[data-term] { text-decoration: underline dotted; cursor: help; }

.bar {
  display: flex; flex-wrap: wrap; align-items: center; gap: 10px 22px;
  background: var(--bar); border-bottom: 3px solid var(--line);
  padding: 10px max(16px, env(safe-area-inset-right, 0px)) 10px max(16px, env(safe-area-inset-left, 0px));
  color: #3b2340;
}
.bar .small { color: #3b2340; }
.brand { display: flex; align-items: center; gap: 10px; }
.brand h1 { font-size: 21px; margin: 0; }
.logo { display: inline-grid; place-items: center; width: 34px; height: 34px; border: 3px solid #3b2340; border-radius: 9px; background: var(--canvas); font-weight: 800; }
.group { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.seg { display: inline-flex; }
.seg button { border-radius: 0; margin-left: calc(-1 * var(--stroke)); background: var(--canvas); color: #3b2340; }
.seg button:first-child { border-radius: 7px 0 0 7px; margin-left: 0; }
.seg button:last-child { border-radius: 0 7px 7px 0; }
.seg button.on { background: #3b2340; color: var(--canvas); }
.file input { position: absolute; opacity: 0; width: 1px; }
.file { position: relative; }

.intro { padding: 10px max(16px, env(safe-area-inset-right, 0px)) 0 max(16px, env(safe-area-inset-left, 0px)); display: flex; flex-wrap: wrap; gap: 4px 16px; align-items: baseline; }
.intro p { margin: 0; max-width: 80ch; }
.intro .privacy { font-size: 13px; color: var(--muted); }

.layout {
  display: grid; gap: 14px;
  grid-template-columns: minmax(250px, 1fr) minmax(0, 2.2fr) minmax(240px, 1fr);
  padding: 12px max(16px, env(safe-area-inset-right, 0px)) 24px max(16px, env(safe-area-inset-left, 0px));
  align-items: start;
}
@media (max-width: 1100px) { .layout { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); } .reader { grid-column: 1 / -1; order: -1; } }
@media (max-width: 700px) { .layout { grid-template-columns: minmax(0, 1fr); } }
.panel {
  border: var(--stroke) solid var(--line); border-radius: var(--radius);
  background: var(--panel); padding: 12px 14px; display: grid; gap: 10px; min-width: 0;
}
.field { display: grid; gap: 3px; }
textarea, input[type=text] {
  width: 100%; border: var(--stroke) solid var(--line); border-radius: 7px; background: #fff; color: #3b2340;
  padding: 6px 8px; resize: vertical;
}
.code { font-family: var(--mono); font-size: 13px; line-height: 1.45; }
.code-ref { font-family: var(--mono); font-size: 12px; overflow-wrap: anywhere; }
details summary { cursor: pointer; font-weight: 700; font-size: 13px; }
.errors { border: var(--stroke) solid var(--error); border-radius: 7px; padding: 6px 10px; color: var(--error); background: var(--panel); }
.errors ul { margin: 4px 0 0; padding-left: 18px; font-size: 13px; }

.reader { background: var(--canvas); color: #3b2340; }
.formula { overflow-x: auto; }
.formula svg { display: block; max-width: 100%; height: auto; margin: 0 auto; }
.fb-scrub { cursor: ew-resize; }
.fb-scrub:focus { outline: none; }
.fb-scrub:focus-visible { stroke: #1d6fa3; stroke-width: 40; stroke-dasharray: 60 40; }
[data-c] { cursor: help; }
[data-scrub] { cursor: ew-resize; }
.fb-edit {
  width: 100%; height: 100%; font: 600 520px/1 var(--body); text-align: center;
  border: 40px solid #3b2340; border-radius: 120px; background: #fff; color: #3b2340; padding: 0;
}
.prose-out { margin: 0; font-size: 17px; max-width: 70ch; }
.prose-out .link { text-decoration-line: underline; text-decoration-thickness: 2px; text-underline-offset: 4px; font-weight: 600; cursor: help; border-radius: 4px; }
.prose-out .link.on { background: #fff; outline: 2px solid currentColor; }
.controls { display: grid; gap: 6px; }
.control { display: grid; grid-template-columns: minmax(120px, auto) minmax(0, 1fr) auto; align-items: center; gap: 10px; }
.control.limit { grid-template-columns: minmax(120px, auto) minmax(0, 1fr) minmax(0, 1fr) auto; }
.control-label { display: inline-flex; align-items: center; gap: 6px; font-weight: 600; }
.control input[type=range] { width: 100%; }
.control output { font-family: var(--mono); font-variant-numeric: tabular-nums; min-width: 5ch; text-align: right; }
.plot svg { display: block; width: 100%; max-width: 680px; height: auto; }
.plot-error { color: var(--error); font-size: 13px; margin: 0; }
.stepbar { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; border: var(--stroke) solid #3b2340; border-radius: 8px; background: #f6e7c4; padding: 6px 8px; }
.stepbar ol { display: flex; flex-wrap: wrap; gap: 6px; list-style: none; margin: 0; padding: 0; counter-reset: step; }
.stepbar li { counter-increment: step; }
.stepbar ol button { background: #fff; color: #3b2340; font-weight: 500; }
.stepbar ol button::before { content: counter(step) ". "; font-weight: 800; }
.stepbar ol button.on { background: #3b2340; color: #fff6e0; }

.badge { display: inline-grid; place-items: center; min-width: 22px; height: 22px; border-radius: 50%; border: 2px solid #3b2340; color: #fff; font-size: 12px; font-weight: 800; }
.row { display: flex; align-items: baseline; justify-content: space-between; gap: 8px; flex-wrap: wrap; }
.meter { display: grid; grid-auto-flow: column; gap: 4px; }
.meter .cell { height: 10px; border: 2px solid var(--line); border-radius: 3px; background: var(--panel); }
.meter .cell.on { background: var(--teal); }
.concept-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.concept { border: var(--stroke) solid var(--line); border-radius: 8px; padding: 6px 8px; background: #fff; color: #3b2340; display: grid; gap: 4px; }
.concept.on { background: #f5da92; }
.concept-top { display: flex; align-items: center; gap: 8px; }
.concept-top strong { flex: 1; }
.sample { width: 54px; display: inline-block; }
.sample svg { display: block; width: 100%; height: auto; }
.say { margin: 0; font-size: 13px; color: #6d5a68; }
.toggles { display: flex; flex-wrap: wrap; gap: 4px; }
.toggle { font-size: 12px; padding: 1px 8px; border-width: 1.5px; background: #fff; font-weight: 500; }
.toggle.on { background: #4fa3a0; color: #fff; }
.remove { padding: 0 8px; line-height: 1.4; }
.eye { font-size: 12px; padding: 0 8px; font-weight: 500; }
.eye.off { background: #3b2340; color: #fff6e0; }
.check { display: inline-flex; align-items: center; gap: 4px; }
.selection p { margin: 0 0 6px; }
.selection code { font-family: var(--mono); background: #fff; border: 1px solid var(--soft); padding: 1px 5px; border-radius: 4px; color: #3b2340; }
.about p { font-size: 13px; }
#message:not(:empty) { margin: 0 16px 16px; color: var(--error); font-weight: 600; }
dialog { border: 3px solid #3b2340; border-radius: 12px; background: #fff6e0; color: #3b2340; width: min(720px, 92vw); }
dialog::backdrop { background: rgba(59, 35, 64, .45); }
dialog textarea { margin: 8px 0; }

/* the embed: the reader view alone */
.embed-page { background: var(--canvas); }
.embed-page .reader { border: 0; border-radius: 0; padding: 8px max(12px, env(safe-area-inset-right, 0px)) 8px max(12px, env(safe-area-inset-left, 0px)); }
.embed-foot { display: flex; justify-content: space-between; align-items: center; gap: 8px; flex-wrap: wrap; font-size: 13px; }
.embed-foot a { color: #1d6fa3; font-weight: 600; }