/* =========================================================
   DEMO SHELL — shared chrome for every interactive under
   resources/demos/<slug>/. Requires tokens.css to be loaded
   first (it owns the palette).

   Layout contract:
     .demo-head        page header: back link, title, theme toggle
     .demo-grid        stage (canvas/plot) + controls sidebar
       > .stage          the visual; pinned to the viewport on desktop,
                         and collapses above the controls on mobile
       > .controls       sliders, toggles, readouts; this column scrolls
     .why              the "misconception this fixes" footer

   Everything is theme-aware and phone-first.
   ========================================================= */

*,
*::before,
*::after { box-sizing: border-box; margin: 0; padding: 0; }

/* Any author `display:` rule below out-specifies the UA rule for [hidden],
   which silently leaves hidden elements on screen. Restore it once, here,
   so toggling `el.hidden` is reliable in every demo. */
[hidden] { display: none !important; }

body {
  font-family: 'Poppins', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-size: 15px;
  line-height: 1.6;
  color: var(--text-2);
  background: var(--bg);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -webkit-text-size-adjust: 100%;
  padding: 18px 16px 72px;
  transition: background 0.3s ease, color 0.3s ease;
}

h1, h2, h3, h4 { color: var(--text); line-height: 1.25; font-weight: 600; }
a { color: var(--accent-strong); text-decoration: none; transition: color 0.2s ease; }
a:hover { color: var(--accent); }
img, svg, canvas { max-width: 100%; display: block; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 6px;
}

.wrap { max-width: 1100px; margin: 0 auto; }

/* =========================================================
   Header
   ========================================================= */
.demo-head {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 18px;
}
.demo-head .dh-body { flex: 1; min-width: 0; }

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12.5px;
  font-weight: 500;
  color: var(--muted);
  margin-bottom: 6px;
}
.back-link:hover { color: var(--accent-strong); }
.back-link::before { content: '\2190'; font-size: 14px; }

.demo-title { font-size: 24px; margin-bottom: 4px; }
.demo-sub { font-size: 14px; color: var(--muted); }

/* course / unit chips */
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 9px; }
.tag {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.02em;
  padding: 3px 9px;
  border-radius: 20px;
  background: var(--surface-2);
  border: 1px solid var(--line);
  color: var(--muted);
  white-space: nowrap;
}
.tag.is-accent { background: var(--accent-soft); border-color: var(--accent-line); color: var(--accent-strong); }
.tag.is-bio    { background: var(--ok-soft);   border-color: transparent; color: var(--ok); }
.tag.is-chem   { background: var(--warn-soft); border-color: transparent; color: var(--warn); }

/* =========================================================
   Layout
   ========================================================= */
.demo-grid {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 18px;
  align-items: start;
}
.demo-grid > * { min-width: 0; }
.demo-grid.controls-left { grid-template-columns: 300px 1fr; }
.demo-grid.wide-controls { grid-template-columns: 1fr 360px; }

@media (max-width: 880px) {
  .demo-grid,
  .demo-grid.controls-left,
  .demo-grid.wide-controls { grid-template-columns: 1fr; }
  /* stage always reads first on a phone, whatever the desktop order */
  .demo-grid > .stage { order: -1; }
}

.panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 15px 16px;
  box-shadow: var(--shadow-sm);
  transition: background 0.3s ease, border-color 0.3s ease;
}
.panel + .panel { margin-top: 14px; }

.panel-title {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 12px;
}

.controls { display: flex; flex-direction: column; gap: 14px; }

@media (min-width: 881px) {
  /* The demonstration holds still and the controls column is what scrolls.
     A student changing a slider far down the panel must still be able to see
     what it does. max-height keeps a tall stage reachable: it pins to the
     viewport and scrolls internally instead of having its bottom cut off. */
  .demo-grid > .stage {
    position: sticky;
    top: 18px;
    max-height: calc(100vh - 36px);
    overflow-y: auto;
  }

  /* Demos still carry class="controls sticky" from the original template.
     The stage pins now, so that class is deliberately neutralised here
     rather than edited out of every demo. */
  .controls.sticky { position: static; top: auto; }
}

/* =========================================================
   Stage — canvas / SVG surface
   ========================================================= */
.stage {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 14px;
  box-shadow: var(--shadow-sm);
  transition: background 0.3s ease, border-color 0.3s ease;
}
/* Demo.canvas() sizes the bitmap; CSS owns the box. */
.stage canvas { width: 100%; height: auto; display: block; border-radius: 10px; }
.stage-caption { font-size: 12.5px; color: var(--muted); margin-top: 10px; }

/* =========================================================
   Controls — sliders
   ========================================================= */
.ctrl { display: block; }
.ctrl-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 5px;
}
.ctrl-label { font-size: 13px; font-weight: 500; color: var(--text); }
.ctrl-value {
  font-size: 13px;
  font-variant-numeric: tabular-nums;
  color: var(--accent-strong);
  font-weight: 600;
  white-space: nowrap;
}
.ctrl-hint { font-size: 11.5px; color: var(--muted); margin-top: 4px; line-height: 1.45; }

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 22px;
  background: transparent;
  cursor: pointer;
  display: block;
}
input[type="range"]::-webkit-slider-runnable-track {
  height: 6px; border-radius: 4px; background: var(--track);
}
input[type="range"]::-moz-range-track {
  height: 6px; border-radius: 4px; background: var(--track);
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px; height: 18px; margin-top: -6px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--surface);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.28);
  transition: background 0.15s ease;
}
input[type="range"]::-moz-range-thumb {
  width: 15px; height: 15px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--surface);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.28);
}
input[type="range"]:hover::-webkit-slider-thumb { background: var(--accent-strong); }
input[type="range"]:disabled { opacity: 0.45; cursor: not-allowed; }

/* =========================================================
   Controls — buttons, segmented control, inputs
   ========================================================= */
.btn {
  font: inherit;
  font-size: 13px;
  font-weight: 500;
  background: var(--surface-2);
  color: var(--text-2);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 8px 14px;
  cursor: pointer;
  transition: border-color 0.2s ease, color 0.2s ease, background 0.2s ease;
}
.btn:hover { border-color: var(--accent-line); color: var(--accent-strong); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { background: var(--accent-strong); border-color: var(--accent-strong); color: #fff; }
.btn-row { display: flex; flex-wrap: wrap; gap: 8px; }
.btn-row .btn { flex: 1 1 auto; }

/* segmented control — for tabbed demos (Allele Machine, Electronic Structure Bench) */
.seg {
  display: flex;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 11px;
  padding: 3px;
  gap: 3px;
}
.seg button {
  font: inherit;
  font-size: 12.5px;
  font-weight: 500;
  flex: 1;
  padding: 7px 10px;
  border: 0;
  border-radius: 8px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
  white-space: nowrap;
}
.seg button:hover { color: var(--text); }
.seg button[aria-selected="true"] {
  background: var(--surface);
  color: var(--accent-strong);
  box-shadow: var(--shadow-sm);
}

/* checkbox / switch rows */
.check {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 13px;
  color: var(--text);
  cursor: pointer;
  user-select: none;
}
.check input { width: 16px; height: 16px; accent-color: var(--accent); cursor: pointer; flex: none; }

input[type="number"],
input[type="text"],
select {
  font: inherit;
  font-size: 13px;
  width: 100%;
  padding: 7px 10px;
  color: var(--text);
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 9px;
  transition: border-color 0.2s ease;
}
input[type="number"]:focus,
input[type="text"]:focus,
select:focus { outline: none; border-color: var(--accent); }
input.is-bad { border-color: var(--bad); }

/* =========================================================
   Readouts — the big live numbers
   ========================================================= */
.readouts { display: grid; grid-template-columns: repeat(auto-fit, minmax(96px, 1fr)); gap: 10px; }
.readout {
  background: var(--surface-2);
  border: 1px solid var(--line-soft);
  border-radius: 11px;
  padding: 9px 11px;
  min-width: 0;
}
.readout .r-label {
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.readout .r-value {
  font-size: 19px;
  font-weight: 600;
  color: var(--text);
  font-variant-numeric: tabular-nums;
  line-height: 1.3;
}
.readout .r-unit { font-size: 12px; font-weight: 500; color: var(--muted); margin-left: 2px; }
.readout.is-accent .r-value { color: var(--accent-strong); }
.readout.is-ok  .r-value { color: var(--ok); }
.readout.is-bad .r-value { color: var(--bad); }

/* horizontal proportion bar (allele frequency, percent yield, ...) */
.bar { height: 15px; background: var(--track); border-radius: 5px; overflow: hidden; display: flex; }
.bar > span { height: 100%; display: block; transition: width 0.25s ease; }

/* =========================================================
   Tables
   ========================================================= */
.tbl { width: 100%; border-collapse: collapse; font-size: 13px; }
.tbl th, .tbl td { padding: 7px 9px; text-align: right; border-bottom: 1px solid var(--line-soft); }
.tbl th {
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
}
.tbl td { font-variant-numeric: tabular-nums; color: var(--text); }
.tbl th:first-child, .tbl td:first-child { text-align: left; color: var(--text-2); }
.tbl tr:last-child td { border-bottom: 0; }
.table-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; }

/* =========================================================
   Callouts + the misconception footer
   ========================================================= */
.note {
  font-size: 13px;
  line-height: 1.55;
  padding: 11px 13px;
  border-radius: 11px;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  color: var(--text-2);
}
.note.warn { border-left-color: var(--warn); background: var(--warn-soft); }
.note.bad  { border-left-color: var(--bad);  background: var(--bad-soft); }
.note strong { color: var(--text); font-weight: 600; }

/* Every demo ends with this: what it is for, and the trap it defuses. */
.why {
  margin-top: 22px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 16px 18px;
  box-shadow: var(--shadow-sm);
}
.why h2 {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 9px;
}
.why p { font-size: 14px; line-height: 1.65; color: var(--text-2); }
.why p + p { margin-top: 9px; }
.why strong { color: var(--text); font-weight: 600; }

/* =========================================================
   Theme toggle (matches the portfolio's .theme-fab)
   ========================================================= */
.theme-toggle {
  flex: none;
  width: 40px;
  height: 40px;
  border-radius: 11px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 17px;
  color: var(--text-2);
  background: var(--surface-2);
  border: 1px solid var(--line);
  cursor: pointer;
  transition: color 0.2s ease, border-color 0.2s ease;
}
.theme-toggle:hover { color: var(--accent-strong); border-color: var(--accent-line); }
.theme-toggle .bi-sun-fill { display: none; }
:root[data-theme="light"] .theme-toggle .bi-sun-fill { display: block; }
:root[data-theme="light"] .theme-toggle .bi-moon-stars-fill { display: none; }

/* =========================================================
   Utilities
   ========================================================= */
.stack   { display: flex; flex-direction: column; gap: 10px; }
.stack-s { display: flex; flex-direction: column; gap: 6px; }
.row     { display: flex; align-items: center; gap: 10px; }
.row-between { display: flex; align-items: center; justify-content: space-between; gap: 10px; }
.sep { height: 1px; background: var(--line-soft); margin: 4px 0; border: 0; }
.muted { color: var(--muted); }
.small { font-size: 12.5px; }
.num { font-variant-numeric: tabular-nums; }
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}

@media (max-width: 560px) {
  body { padding: 14px 12px 64px; }
  .demo-title { font-size: 20px; }
  .panel, .stage { padding: 13px; border-radius: 14px; }
}

/* Users who ask for less motion get no transitions or animation. */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}

/* suppress transition ghosting while the window is being resized */
.no-transition *,
.no-transition *::before,
.no-transition *::after { transition: none !important; }