/* ==========================================================================
   THE BENCH — visual system
   Concept: a working electronics bench. Colours are pulled from real board
   materials: solder-mask green, silkscreen white, gold-plated pads, copper
   traces, flux residue. Structure borrows from technical manuals: call
   numbers, hairline rules, legend labels.
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Bricolage+Grotesque:opsz,wght@12..96,400;12..96,600;12..96,700;12..96,800&family=IBM+Plex+Mono:wght@400;500;600;700&family=IBM+Plex+Sans:wght@400;500;600;700&display=swap');

:root {
  /* solder mask */
  --board:    #061512;
  --board-2:  #0b1f1a;
  --board-3:  #102a23;
  --board-4:  #16362d;
  --line:     #1e3d34;
  --line-2:   #2a5347;

  /* silkscreen */
  --silk:     #e9f2ee;
  --silk-2:   #a9c0b7;
  --silk-3:   #7b968c;

  /* plating + traces */
  --gold:     #e3ac3f;
  --gold-dim: #8a6a25;
  --copper:   #d9754a;
  --flux:     #59cfba;
  --red:      #e8635a;

  --edge:     0 1px 0 rgba(255,255,255,.03) inset;
  --lift:     0 2px 0 rgba(0,0,0,.35), 0 18px 44px -22px rgba(0,0,0,.9);
  --r:        4px;
  --r-lg:     8px;

  --display: 'Bricolage Grotesque', 'Arial Black', sans-serif;
  --sans: 'IBM Plex Sans', ui-sans-serif, system-ui, -apple-system, sans-serif;
  --mono: 'IBM Plex Mono', ui-monospace, 'SF Mono', Menlo, Consolas, monospace;

  --rail: 268px;
  --head: 54px;
  --fs: 16px;
}

html[data-theme="light"] {
  --board:    #eceee9;
  --board-2:  #f6f7f4;
  --board-3:  #e3e7e1;
  --board-4:  #d7ddd6;
  --line:     #c9d1c9;
  --line-2:   #adb9ad;
  --silk:     #131b18;
  --silk-2:   #4c5b55;
  --silk-3:   #6d7c75;
  --gold:     #8a5f0b;
  --gold-dim: #b99852;
  --copper:   #b04d21;
  --flux:     #0a7566;
  --red:      #b3271e;
  --edge:     0 1px 0 rgba(255,255,255,.7) inset;
  --lift:     0 1px 0 rgba(0,0,0,.06), 0 14px 34px -22px rgba(0,0,0,.4);
}

* { box-sizing: border-box; }
html { font-size: var(--fs); -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--board);
  color: var(--silk);
  font-family: var(--sans);
  font-size: 0.95rem;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* faint board texture: trace grid */
body::before {
  content: '';
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 46px 46px;
  opacity: .16;
}
html[data-theme="light"] body::before { opacity: .34; }

button, input, textarea, select { font: inherit; color: inherit; }
button { cursor: pointer; background: none; border: 0; }
a { color: var(--flux); }

::selection { background: var(--gold); color: #0a1a15; }

:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 2px;
}

/* ---------- utility type ---------- */
.legend {
  font-family: var(--mono);
  font-size: .66rem;
  font-weight: 600;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--silk-3);
}
.ref {
  font-family: var(--mono);
  font-size: .72rem;
  font-weight: 600;
  letter-spacing: .06em;
  color: var(--gold);
}

/* ==========================================================================
   BOOT
   ========================================================================== */
#boot {
  position: fixed; inset: 0; z-index: 999;
  background: var(--board);
  display: grid; place-content: center;
  font-family: var(--mono); font-size: .8rem;
  color: var(--silk-3);
  transition: opacity .4s ease;
}
#boot.gone { opacity: 0; pointer-events: none; }
#boot pre { margin: 0; line-height: 1.9; }
#boot b { color: var(--gold); font-weight: 600; }

/* ==========================================================================
   HEADER
   ========================================================================== */
.masthead {
  position: fixed; top: 0; left: 0; right: 0; z-index: 60;
  height: var(--head);
  display: flex; align-items: center; gap: 18px;
  padding: 0 16px;
  background: color-mix(in srgb, var(--board) 92%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}
.mark {
  display: flex; align-items: baseline; gap: 9px;
  text-decoration: none; color: var(--silk);
  white-space: nowrap;
}
.mark-pad {
  width: 22px; height: 22px; border-radius: 50%;
  border: 2px solid var(--gold);
  background: radial-gradient(circle at 35% 30%, var(--gold), var(--gold-dim));
  position: relative; align-self: center;
  flex: none;
}
.mark-pad::after {
  content: ''; position: absolute; inset: 6px;
  border-radius: 50%; background: var(--board);
}
.mark b {
  font-family: var(--display);
  font-size: 1.02rem; font-weight: 800;
  letter-spacing: -.02em;
}
.mark span {
  font-family: var(--mono); font-size: .6rem; font-weight: 600;
  letter-spacing: .22em; color: var(--silk-3); text-transform: uppercase;
}

.tabs { display: flex; gap: 2px; margin-left: auto; overflow-x: auto; scrollbar-width: none; }
.tabs::-webkit-scrollbar { display: none; }
.tabs button {
  font-family: var(--mono); font-size: .72rem; font-weight: 600;
  letter-spacing: .1em; text-transform: uppercase;
  padding: 8px 12px; color: var(--silk-3);
  border-radius: var(--r);
  position: relative;
}
.tabs button:hover { color: var(--silk); background: var(--board-3); }
.tabs button.on { color: var(--gold); }
.tabs button.on::after {
  content: ''; position: absolute; left: 12px; right: 12px; bottom: 2px;
  height: 2px; background: var(--gold); border-radius: 2px;
}

.head-tools { display: flex; gap: 2px; align-items: center; }
.icon-btn {
  width: 32px; height: 32px; border-radius: var(--r);
  display: grid; place-items: center;
  color: var(--silk-3); border: 1px solid transparent;
  font-family: var(--mono); font-size: .78rem;
}
.icon-btn:hover { color: var(--silk); background: var(--board-3); border-color: var(--line); }
#railToggle { display: none; }

/* ==========================================================================
   LAYOUT
   ========================================================================== */
.shell { position: relative; z-index: 1; padding-top: var(--head); }

.rail {
  position: fixed; top: var(--head); bottom: 0; left: 0; width: var(--rail);
  overflow-y: auto; overscroll-behavior: contain;
  border-right: 1px solid var(--line);
  background: var(--board-2);
  padding: 14px 0 40px;
  z-index: 50;
}
.rail::-webkit-scrollbar, .stage-scroll::-webkit-scrollbar { width: 9px; }
.rail::-webkit-scrollbar-thumb, .stage-scroll::-webkit-scrollbar-thumb {
  background: var(--line-2); border-radius: 9px;
}

.rail-head { padding: 4px 16px 14px; border-bottom: 1px solid var(--line); margin-bottom: 10px; }
.rail-head .legend { display: block; margin-bottom: 8px; }
.meter { height: 5px; background: var(--board-4); border-radius: 3px; overflow: hidden; }
.meter i {
  display: block; height: 100%; width: 0;
  background: linear-gradient(90deg, var(--copper), var(--gold));
  transition: width .45s cubic-bezier(.2,.8,.2,1);
}
.rail-head small {
  display: block; margin-top: 7px;
  font-family: var(--mono); font-size: .68rem; color: var(--silk-3);
}

.drawer { border-bottom: 1px solid var(--line); }
.drawer-btn {
  width: 100%; display: grid;
  grid-template-columns: 46px 1fr auto; align-items: center; gap: 8px;
  padding: 11px 12px 11px 0; text-align: left;
}
.drawer-btn .ref { text-align: right; padding-right: 2px; font-size: .68rem; }
.drawer-btn strong {
  font-family: var(--display); font-size: .9rem; font-weight: 700;
  letter-spacing: -.01em; display: block; line-height: 1.25;
}
.drawer-btn em {
  font-style: normal; font-family: var(--mono); font-size: .62rem;
  color: var(--silk-3); letter-spacing: .04em;
}
.drawer-btn .tally {
  font-family: var(--mono); font-size: .64rem; color: var(--silk-3);
  padding-right: 12px;
}
.drawer-btn:hover { background: var(--board-3); }
.drawer.open .drawer-btn { background: var(--board-3); }
.drawer.open .drawer-btn .ref { color: var(--gold); }

.drawer-list { display: none; padding: 2px 12px 12px 46px; }
.drawer.open .drawer-list { display: block; }
.drawer-list button {
  display: flex; align-items: baseline; gap: 8px;
  width: 100%; text-align: left; padding: 6px 8px;
  border-radius: var(--r); color: var(--silk-2); font-size: .82rem;
  line-height: 1.4;
}
.drawer-list button:hover { background: var(--board-3); color: var(--silk); }
.drawer-list button.on { background: var(--board-4); color: var(--silk); box-shadow: inset 2px 0 0 var(--gold); }
.drawer-list .dot {
  flex: none; width: 6px; height: 6px; border-radius: 50%;
  border: 1px solid var(--line-2); margin-top: 7px;
}
.drawer-list button.done .dot { background: var(--gold); border-color: var(--gold); }

.stage { margin-left: var(--rail); min-height: calc(100vh - var(--head)); }
.wrap { max-width: 1420px; margin: 0 auto; padding: 26px 30px 90px; }

/* ==========================================================================
   PANELS
   ========================================================================== */
.panel {
  background: var(--board-2);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  box-shadow: var(--edge);
}
.panel-head {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 14px; border-bottom: 1px solid var(--line);
  background: var(--board-3);
  border-radius: var(--r-lg) var(--r-lg) 0 0;
}
.panel-head .legend { flex: 1; }
.panel-body { padding: 16px; }

/* ==========================================================================
   LESSON
   ========================================================================== */
.lesson-top { border-bottom: 1px solid var(--line); padding-bottom: 20px; margin-bottom: 22px; }
.crumb { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; flex-wrap: wrap; }
.crumb .ref { background: var(--board-3); border: 1px solid var(--line); padding: 3px 8px; border-radius: var(--r); }
.chip {
  font-family: var(--mono); font-size: .64rem; font-weight: 600;
  letter-spacing: .12em; text-transform: uppercase;
  padding: 3px 8px; border-radius: var(--r);
  border: 1px solid var(--line); color: var(--silk-3);
}
h1.title {
  font-family: var(--display);
  font-size: clamp(1.9rem, 3.6vw, 2.9rem);
  font-weight: 800; letter-spacing: -.035em; line-height: 1.03;
  margin: 0 0 12px; max-width: 22ch;
}
.goal {
  display: flex; gap: 10px; align-items: baseline;
  font-size: 1.02rem; color: var(--silk-2); max-width: 62ch;
}
.goal::before {
  content: 'GOAL'; flex: none;
  font-family: var(--mono); font-size: .62rem; font-weight: 700;
  letter-spacing: .14em; color: var(--gold);
  border: 1px solid var(--gold-dim); padding: 1px 5px; border-radius: 3px;
}

.lesson-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr); gap: 22px; align-items: start; }

.prose > * + * { margin-top: 18px; }
.prose p { margin: 0; font-size: 1rem; }
.prose .lead { font-size: 1.06rem; line-height: 1.66; }

.aside-block {
  border-left: 2px solid var(--gold);
  padding: 2px 0 2px 14px;
}
.aside-block .legend { display: block; margin-bottom: 4px; color: var(--gold); }
.aside-block p { color: var(--silk-2); font-size: .94rem; }

.picture {
  border: 1px solid var(--line); border-left: 2px solid var(--copper);
  background: var(--board-2);
  border-radius: 0 var(--r) var(--r) 0; padding: 13px 15px;
}
.picture .legend { display: block; margin-bottom: 4px; color: var(--copper); }
.picture p { font-size: .94rem; color: var(--silk-2); font-style: italic; }

.keylist { list-style: none; margin: 0; padding: 0; }
.keylist li {
  display: grid; grid-template-columns: 26px 1fr; gap: 6px;
  padding: 8px 0; border-top: 1px dashed var(--line);
  font-size: .92rem; color: var(--silk-2);
}
.keylist li:first-child { border-top: 0; }
.keylist li::before {
  content: counter(k, decimal-leading-zero);
  counter-increment: k;
  font-family: var(--mono); font-size: .68rem; font-weight: 600;
  color: var(--gold-dim); padding-top: 3px;
}
.keylist { counter-reset: k; }

.callout {
  display: grid; grid-template-columns: auto 1fr; gap: 10px;
  padding: 12px 14px; border-radius: var(--r);
  border: 1px solid var(--line); background: var(--board-3);
  font-size: .92rem;
}
.callout b {
  font-family: var(--mono); font-size: .62rem; font-weight: 700;
  letter-spacing: .12em; padding-top: 3px;
}
.callout.tip  { border-color: color-mix(in srgb, var(--flux) 40%, var(--line)); }
.callout.tip b { color: var(--flux); }
.callout.warn { border-color: color-mix(in srgb, var(--copper) 45%, var(--line)); }
.callout.warn b { color: var(--copper); }
.callout.note b { color: var(--gold); }

.termrow { display: flex; flex-wrap: wrap; gap: 6px; }
.termrow button {
  font-family: var(--mono); font-size: .7rem;
  padding: 4px 9px; border-radius: 20px;
  border: 1px solid var(--line); color: var(--silk-3);
}
.termrow button:hover { border-color: var(--gold); color: var(--gold); }

/* ==========================================================================
   THE BENCH  (editor + scrubber + panels)
   ========================================================================== */
.bench { position: sticky; top: calc(var(--head) + 14px); }

.bench-bar {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 10px; border-bottom: 1px solid var(--line);
  background: var(--board-3);
  border-radius: var(--r-lg) var(--r-lg) 0 0;
  flex-wrap: wrap;
}
.lang-tag {
  font-family: var(--mono); font-size: .64rem; font-weight: 700;
  letter-spacing: .12em; text-transform: uppercase;
  padding: 3px 7px; border-radius: 3px;
  background: var(--gold); color: #0a1a15;
}
.bench-bar .legend { flex: 1; }

.btn {
  font-family: var(--mono); font-size: .72rem; font-weight: 600;
  letter-spacing: .06em;
  padding: 6px 12px; border-radius: var(--r);
  border: 1px solid var(--line-2); color: var(--silk-2);
  background: var(--board-2);
  transition: .14s;
}
.btn:hover { border-color: var(--gold); color: var(--gold); }
.btn.primary {
  background: var(--gold); color: #0a1a15; border-color: var(--gold);
  font-weight: 700;
}
.btn.primary:hover { filter: brightness(1.1); color: #0a1a15; }
.btn:disabled { opacity: .35; cursor: not-allowed; }
.btn.sm { padding: 4px 9px; font-size: .68rem; }

/* --- code surface --- */
.code-wrap { position: relative; background: var(--board); }
.code-scroll { overflow: auto; max-height: 46vh; }
.code-scroll.tall { max-height: 62vh; }

.code-table { display: table; width: max-content; min-width: 100%; font-family: var(--mono); font-size: .8rem; line-height: 1.62; }
.code-row { display: table-row; }
.code-row > span { display: table-cell; vertical-align: top; }
.ln {
  width: 1%; padding: 0 10px 0 12px; text-align: right;
  color: var(--silk-3); opacity: .5; user-select: none;
  border-right: 1px solid var(--line);
  white-space: nowrap;
}
.lc { padding: 0 14px 0 12px; white-space: pre; }
.code-row.note-line .ln { color: var(--gold); opacity: 1; cursor: pointer; }
.code-row.note-line .ln::after { content: '•'; margin-left: 3px; }
.code-row.hot { background: color-mix(in srgb, var(--gold) 12%, transparent); }
.code-row.hot .ln { color: var(--gold); opacity: 1; }
.code-row.hot .lc { box-shadow: inset 2px 0 0 var(--gold); }
.code-row.errline { background: color-mix(in srgb, var(--red) 16%, transparent); }
.code-row.errline .ln { color: var(--red); opacity: 1; }
.code-row.pick { background: var(--board-3); cursor: pointer; }

/* syntax */
.t-kw  { color: var(--copper); font-weight: 600; }
.t-typ { color: var(--flux); }
.t-str { color: var(--gold); }
.t-num { color: #b9e08a; }
.t-com { color: var(--silk-3); font-style: italic; opacity: .8; }
.t-fn  { color: #9ec9ff; }
.t-pun { color: var(--silk-2); }
html[data-theme="light"] .t-num { color: #4a7a1e; }
html[data-theme="light"] .t-fn  { color: #1f5fa8; }

.editor-host { position: relative; min-width: 100%; width: max-content; }
.editor-host textarea {
  position: absolute; inset: 0; width: 100%; height: 100%;
  padding: 0 14px 0 calc(12px + var(--gutter, 44px));
  margin: 0; border: 0; resize: none; outline: none;
  background: transparent; color: transparent; caret-color: var(--gold);
  font-family: var(--mono); font-size: .8rem; line-height: 1.62;
  white-space: pre; overflow: hidden;
  tab-size: 2;
}
.editor-host textarea::selection { background: color-mix(in srgb, var(--gold) 35%, transparent); color: transparent; }

/* --- line note --- */
.line-note {
  border-top: 1px solid var(--line);
  background: var(--board-3);
  padding: 10px 14px; min-height: 54px;
  font-size: .88rem; color: var(--silk-2);
}
.line-note .legend { color: var(--gold); }
.line-note p { margin: 3px 0 0; }

/* ==========================================================================
   SCRUBBER — signature element
   ========================================================================== */
.scope {
  border-top: 1px solid var(--line);
  background: var(--board-3);
  padding: 10px 14px 12px;
}
.scope-top { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
.scope-top .legend { flex: 1; }
.step-readout {
  font-family: var(--mono); font-size: .7rem; color: var(--gold);
  min-width: 78px; text-align: right;
}
.transport { display: flex; gap: 3px; }
.transport button {
  width: 28px; height: 24px; border-radius: 3px;
  border: 1px solid var(--line-2); color: var(--silk-2);
  font-family: var(--mono); font-size: .72rem; line-height: 1;
  display: grid; place-items: center;
}
.transport button:hover:not(:disabled) { border-color: var(--gold); color: var(--gold); }
.transport button:disabled { opacity: .3; cursor: not-allowed; }
.transport button.play.on { background: var(--gold); color: #0a1a15; border-color: var(--gold); }

.track { position: relative; height: 34px; }
.track input[type=range] {
  position: absolute; inset: 0; width: 100%; height: 100%;
  -webkit-appearance: none; appearance: none;
  background: transparent; margin: 0; cursor: pointer;
}
.track input[type=range]::-webkit-slider-runnable-track { height: 34px; background: transparent; }
.track input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 3px; height: 34px; border-radius: 1px;
  background: var(--gold);
  box-shadow: 0 0 10px color-mix(in srgb, var(--gold) 70%, transparent);
}
.track input[type=range]::-moz-range-thumb {
  width: 3px; height: 34px; border: 0; border-radius: 1px; background: var(--gold);
}
.track-canvas {
  position: absolute; inset: 0;
  background: var(--board);
  border: 1px solid var(--line); border-radius: 3px;
  overflow: hidden;
  display: flex; align-items: flex-end;
  pointer-events: none;
}
.track-canvas i {
  flex: 1 1 0; min-width: 1px;
  background: var(--line-2);
  transition: background .1s;
}
.track-canvas i.frame2 { background: var(--flux); opacity: .55; }
.track-canvas i.frame3 { background: var(--copper); opacity: .7; }
.track-canvas i.past { background: var(--gold-dim); }
.track-canvas i.past.frame2 { background: var(--flux); opacity: .9; }
.track-canvas i.past.frame3 { background: var(--copper); opacity: 1; }

/* ==========================================================================
   INSPECTOR
   ========================================================================== */
.inspect { display: grid; grid-template-columns: 1fr 1fr; border-top: 1px solid var(--line); }
.inspect > div { min-width: 0; }
.inspect > div + div { border-left: 1px solid var(--line); }
.inspect h4 {
  margin: 0; padding: 7px 12px;
  border-bottom: 1px solid var(--line);
  font-family: var(--mono); font-size: .62rem; font-weight: 600;
  letter-spacing: .16em; text-transform: uppercase; color: var(--silk-3);
  background: var(--board-3);
}
.inspect-body { padding: 8px 12px; min-height: 118px; max-height: 220px; overflow: auto; }

.frame { margin-bottom: 10px; }
.frame-name {
  font-family: var(--mono); font-size: .68rem; font-weight: 600;
  color: var(--flux); margin-bottom: 3px;
  display: flex; align-items: center; gap: 6px;
}
.frame-name::before {
  content: ''; width: 5px; height: 5px; background: var(--flux); border-radius: 50%;
}
.frame.f0 .frame-name { color: var(--silk-3); }
.frame.f0 .frame-name::before { background: var(--silk-3); }

.vars { width: 100%; border-collapse: collapse; font-family: var(--mono); font-size: .74rem; }
.vars td { padding: 2px 0; vertical-align: top; }
.vars .vn { color: var(--silk); padding-right: 8px; white-space: nowrap; }
.vars .vt { color: var(--silk-3); padding-right: 8px; font-size: .68rem; white-space: nowrap; }
.vars .vv { color: var(--gold); word-break: break-word; }
.vars tr.changed .vv {
  background: color-mix(in srgb, var(--gold) 22%, transparent);
  border-radius: 2px; padding: 0 3px;
}

.console {
  margin: 0; padding: 10px 12px;
  font-family: var(--mono); font-size: .76rem; line-height: 1.55;
  white-space: pre-wrap; word-break: break-word;
  min-height: 96px; max-height: 260px; overflow: auto;
  background: var(--board); color: var(--silk-2);
  border-top: 1px solid var(--line);
  border-radius: 0 0 var(--r-lg) var(--r-lg);
}
.console:empty::before { content: 'Nothing yet. Press Run.'; color: var(--silk-3); opacity: .6; }
.console .err { color: var(--red); }
.console .ok { color: var(--flux); }
.console .cursor { color: var(--gold); }

.preview-frame {
  width: 100%; height: 340px; border: 0;
  background: #fff; display: block;
  border-radius: 0 0 var(--r-lg) var(--r-lg);
}

/* ==========================================================================
   CHALLENGE
   ========================================================================== */
.challenge { margin-top: 22px; border-color: var(--gold-dim); }
.challenge .panel-head { background: color-mix(in srgb, var(--gold) 10%, var(--board-3)); }
.challenge .panel-head .legend { color: var(--gold); }
.challenge-body { padding: 14px 16px; }
.challenge-body p { margin: 0 0 12px; font-size: .98rem; }
.challenge-actions { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.verdict { font-family: var(--mono); font-size: .76rem; font-weight: 600; }
.verdict.pass { color: var(--flux); }
.verdict.fail { color: var(--copper); }
.hint {
  margin-top: 10px; padding: 10px 12px;
  border: 1px dashed var(--line-2); border-radius: var(--r);
  font-size: .88rem; color: var(--silk-2);
}

.next-strip {
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  margin-top: 22px; padding: 16px 18px;
  border: 1px solid var(--line); border-radius: var(--r-lg);
  background: var(--board-2);
}
.next-strip .legend { display: block; }
.next-strip strong { font-family: var(--display); font-size: 1.05rem; font-weight: 700; }

/* ==========================================================================
   HOME
   ========================================================================== */
.hero { padding: 18px 0 30px; }
.hero h1 {
  font-family: var(--display);
  font-size: clamp(2.4rem, 6.2vw, 5rem);
  font-weight: 800; letter-spacing: -.045em; line-height: .94;
  margin: 14px 0 18px; max-width: 16ch;
}
.hero h1 em { font-style: normal; color: var(--gold); }
.hero p { font-size: 1.1rem; color: var(--silk-2); max-width: 58ch; margin: 0; }
.hero-actions { display: flex; gap: 10px; margin-top: 24px; flex-wrap: wrap; }
.btn.big { padding: 11px 20px; font-size: .8rem; }

.stat-row {
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 1px; margin-top: 34px;
  background: var(--line); border: 1px solid var(--line); border-radius: var(--r-lg);
  overflow: hidden;
}
.stat { background: var(--board-2); padding: 16px; }
.stat b {
  display: block; font-family: var(--display);
  font-size: 1.9rem; font-weight: 800; letter-spacing: -.03em; color: var(--gold);
  line-height: 1;
}
.stat span { display: block; margin-top: 5px; }

.map-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 12px; }
.map-card {
  text-align: left; padding: 15px;
  border: 1px solid var(--line); border-radius: var(--r-lg);
  background: var(--board-2); position: relative; overflow: hidden;
  transition: .16s;
}
button.map-card:hover { border-color: var(--gold-dim); transform: translateY(-2px); }
.map-card .ref { display: block; margin-bottom: 8px; }
.map-card strong {
  display: block; font-family: var(--display); font-size: 1.08rem;
  font-weight: 700; letter-spacing: -.02em; margin-bottom: 5px;
}
.map-card p { margin: 0; font-size: .85rem; color: var(--silk-3); line-height: 1.5; }
.map-card .bar {
  position: absolute; left: 0; bottom: 0; height: 2px;
  background: var(--gold); transition: width .4s;
}

.section-head {
  display: flex; align-items: baseline; gap: 14px;
  margin: 40px 0 16px; padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}
.section-head h2 {
  font-family: var(--display); font-size: 1.5rem; font-weight: 700;
  letter-spacing: -.025em; margin: 0;
}
.section-head p { margin: 0; color: var(--silk-3); font-size: .88rem; }

/* ==========================================================================
   GLOSSARY
   ========================================================================== */
.search-bar { display: flex; gap: 8px; margin-bottom: 14px; flex-wrap: wrap; }
.search-bar input {
  flex: 1; min-width: 220px;
  padding: 10px 13px; border-radius: var(--r);
  border: 1px solid var(--line); background: var(--board-2); color: var(--silk);
  font-family: var(--mono); font-size: .84rem; outline: none;
}
.search-bar input:focus { border-color: var(--gold); }
.filters { display: flex; gap: 5px; flex-wrap: wrap; margin-bottom: 16px; }
.filters button {
  font-family: var(--mono); font-size: .66rem; letter-spacing: .06em;
  padding: 4px 10px; border-radius: 20px;
  border: 1px solid var(--line); color: var(--silk-3);
}
.filters button:hover { color: var(--silk); }
.filters button.on { border-color: var(--gold); color: var(--gold); background: color-mix(in srgb, var(--gold) 10%, transparent); }

.term-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(270px, 1fr)); gap: 10px; }
.term-card {
  text-align: left; padding: 13px 14px;
  border: 1px solid var(--line); border-radius: var(--r);
  background: var(--board-2); transition: .14s;
}
.term-card:hover { border-color: var(--gold-dim); }
.term-card .legend { display: block; margin-bottom: 5px; color: var(--copper); }
.term-card strong { display: block; font-size: .98rem; font-weight: 600; margin-bottom: 4px; }
.term-card p { margin: 0; font-size: .84rem; color: var(--silk-3); line-height: 1.5; }
.term-card .use {
  margin-top: 7px; padding-top: 7px; border-top: 1px dashed var(--line);
  color: var(--silk-2); font-size: .8rem;
}

/* ==========================================================================
   SQL TABLE OUTPUT
   ========================================================================== */
.rs { width: 100%; border-collapse: collapse; font-family: var(--mono); font-size: .76rem; }
.rs th {
  text-align: left; padding: 6px 10px;
  border-bottom: 1px solid var(--line-2);
  color: var(--gold); font-weight: 600;
  letter-spacing: .04em; white-space: nowrap;
}
.rs td {
  padding: 5px 10px; border-bottom: 1px solid var(--line);
  color: var(--silk-2); white-space: nowrap;
}
.rs tr:last-child td { border-bottom: 0; }
.rs td.null { color: var(--silk-3); opacity: .5; font-style: italic; }
.rs-wrap { overflow: auto; max-height: 300px; }
.rs-msg {
  padding: 8px 12px; font-family: var(--mono); font-size: .76rem;
  color: var(--flux);
}
.rs-block + .rs-block { border-top: 1px solid var(--line); }
.schema-note { padding: 8px 12px; font-family: var(--mono); font-size: .7rem; color: var(--silk-3); }

/* ==========================================================================
   BENCH PAGE (free playground)
   ========================================================================== */
.pad-layout { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; align-items: start; }
.pad-layout > .panel { min-width: 0; }
.preset-row { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 12px; }

.io-row { display: flex; gap: 8px; align-items: center; padding: 8px 12px; border-top: 1px solid var(--line); background: var(--board-3); }
.io-row .legend { flex: none; }
.io-row input {
  flex: 1; padding: 5px 9px; border-radius: 3px;
  border: 1px solid var(--line); background: var(--board); color: var(--silk);
  font-family: var(--mono); font-size: .74rem; outline: none;
}
.io-row input:focus { border-color: var(--gold); }

/* ==========================================================================
   MISC
   ========================================================================== */
.toast {
  position: fixed; bottom: 20px; left: 50%; transform: translate(-50%, 18px);
  z-index: 300; padding: 9px 16px; border-radius: var(--r);
  background: var(--gold); color: #0a1a15;
  font-family: var(--mono); font-size: .74rem; font-weight: 700;
  letter-spacing: .04em;
  opacity: 0; pointer-events: none; transition: .22s;
  box-shadow: var(--lift);
}
.toast.up { opacity: 1; transform: translate(-50%, 0); }

.scrim { display: none; }

.empty { padding: 50px 20px; text-align: center; color: var(--silk-3); font-family: var(--mono); font-size: .8rem; }

.modal-back {
  position: fixed; inset: 0; z-index: 200;
  background: rgba(0,0,0,.62); backdrop-filter: blur(3px);
  display: none; align-items: center; justify-content: center; padding: 20px;
}
.modal-back.on { display: flex; }
.modal {
  max-width: 520px; width: 100%;
  background: var(--board-2); border: 1px solid var(--line-2);
  border-radius: var(--r-lg); box-shadow: var(--lift);
}
.modal-body { padding: 18px; }
.modal-body h3 { font-family: var(--display); font-size: 1.4rem; margin: 6px 0 10px; letter-spacing: -.02em; }
.modal-body p { margin: 0 0 10px; color: var(--silk-2); font-size: .94rem; }

kbd {
  font-family: var(--mono); font-size: .72rem;
  padding: 1px 5px; border-radius: 3px;
  border: 1px solid var(--line-2); background: var(--board-3); color: var(--silk-2);
}

/* ==========================================================================
   RESPONSIVE
   ========================================================================== */
@media (max-width: 1180px) {
  .lesson-grid { grid-template-columns: 1fr; }
  .bench { position: static; }
  .pad-layout { grid-template-columns: 1fr; }
}

@media (max-width: 900px) {
  :root { --rail: 280px; }
  #railToggle { display: grid; }
  .rail { transform: translateX(-102%); transition: transform .22s ease; box-shadow: var(--lift); }
  .rail.out { transform: none; }
  .stage { margin-left: 0; }
  .scrim { position: fixed; inset: var(--head) 0 0; z-index: 45; background: rgba(0,0,0,.5); }
  .scrim.on { display: block; }
  .wrap { padding: 20px 16px 70px; }
  .tabs button { padding: 8px 9px; font-size: .66rem; }
  .stat-row { grid-template-columns: repeat(2, 1fr); }
  .inspect { grid-template-columns: 1fr; }
  .inspect > div + div { border-left: 0; border-top: 1px solid var(--line); }
}

@media (max-width: 560px) {
  .mark span { display: none; }
  .hero h1 { font-size: 2.3rem; }
  .code-table { font-size: .74rem; }
  .editor-host textarea { font-size: .74rem; }
  .next-strip { flex-direction: column; align-items: stretch; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: .001ms !important; transition-duration: .001ms !important; }
}

@media print {
  .rail, .masthead, .bench-bar, .scope { display: none; }
  .stage { margin: 0; }
}

/* --- narrow-phone trims --- */
@media (max-width: 430px) {
  .mark b { font-size: .9rem; }
  .wrap { padding: 16px 12px 60px; }
  .hero h1 { font-size: 2rem; }
  .stat-row { grid-template-columns: 1fr 1fr; }
  .transport button { width: 26px; }
  .btn { padding: 6px 9px; }
}

/* Keep the curriculum legible and keyboard selection visible. */
.drawer-btn strong,.drawer-list button{font-size:.875rem;line-height:1.5}
.drawer-list button{min-height:40px}
.drawer-btn:focus-visible,.drawer-list button:focus-visible{outline:2px solid var(--gold);outline-offset:-3px}
@media(max-width:900px){.tabs button{font-size:.875rem;min-height:44px}.masthead{gap:10px}.tabs{min-width:0}.tabs button{flex-shrink:0}.drawer-list button{min-height:44px}}


@media(max-width:600px){:root{--head:104px}.masthead{height:var(--head);flex-wrap:wrap;gap:0 12px;padding:7px 14px}.tabs{order:4;flex:0 0 100%;margin:0;justify-content:space-between}.head-tools{margin-left:auto}}

.prediction-panel{padding:24px;border:1px solid var(--gold-dim,#6b5b30);border-left:3px solid var(--gold);margin-bottom:18px}.prediction-panel h3{font-size:25px;margin:12px 0}.prediction-panel label{font-size:15px;line-height:1.6;display:block;margin:12px 0}.prediction-panel textarea{width:100%;padding:12px;background:transparent;color:inherit;border:1px solid var(--line,#665f53);font:15px/1.6 monospace;resize:vertical;margin-bottom:14px}.prediction-panel p{font-size:14px;line-height:1.65;margin:14px 0 0}.prediction-panel p[data-match=true]{color:var(--gold)}.runtime-note{margin:16px 0 24px;font-size:14px;line-height:1.65}.runtime-note summary{cursor:pointer;min-height:44px;padding:12px 0}.runtime-note p{max-width:65ch;opacity:.8}.prediction-panel :focus-visible{outline:2px solid var(--gold);outline-offset:4px}