:root {
  --lw: 104px; /* source: the field names column */
  --bg: #0f1115;
  --panel: #161a21;
  --line: #262c36;
  --edge: #3b4452; /* panel borders: stronger than --line so the boxes stand apart */
  --text: #d7dce4;
  --muted: #7d8696;
  --accent: #f7931a;
  --ok: #3fb950;
  --fail: #f85149;
  --k-sig: #f7931a;
  --k-pubkey: #58a6ff;
  --k-hash: #bc8cff;
  --k-num: #8b949e;
  --mono: ui-monospace, 'JetBrains Mono', 'SFMono-Regular', Menlo, monospace;
  color-scheme: dark;
}

/* theme follows the system unless data-theme on <html> overrides it */
@media (prefers-color-scheme: light) {
  :root:not([data-theme='dark']) {
    --bg: #f6f7f9;
    --panel: #ffffff;
    --line: #dde1e7;
    --edge: #b8c0cb;
    --text: #1f2328;
    --muted: #656d76;
    --k-num: #6e7781;
    color-scheme: light;
  }
}
:root[data-theme='light'] {
  --bg: #f6f7f9;
  --panel: #ffffff;
  --line: #dde1e7;
  --edge: #b8c0cb;
  --text: #1f2328;
  --muted: #656d76;
  --k-num: #6e7781;
  color-scheme: light;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font: 14px/1.45 system-ui, sans-serif;
}

code, kbd, .script, .item, .op-title, .chip, select { font-family: var(--mono); }

button {
  font: inherit;
  color: inherit;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 4px 10px;
  cursor: pointer;
}
button:hover:not(:disabled) { border-color: var(--muted); }
button:disabled { opacity: 0.35; cursor: default; }

kbd {
  font-size: 11px;
  padding: 0 4px;
  border: 1px solid var(--line);
  border-radius: 4px;
  color: var(--muted);
}

.muted, .k { color: var(--muted); }
.k { font-size: 12px; }

h2 {
  margin: 0 0 8px;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}
h2 .muted { text-transform: none; letter-spacing: 0; font-weight: 400; }

/* header */

header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 16px;
  padding: 8px 16px;
  border-bottom: 1px solid var(--line);
}

/* Orbitron (OFL 1.1, LICENSE-OFL): the original variable font, unmodified */
@font-face { font-family: 'Orbitron'; src: url('orbitron.ttf') format('truetype'); font-weight: 400 900; font-display: swap; }
.brand { font-family: 'Orbitron', sans-serif; font-weight: 500; font-size: 16px; letter-spacing: 1.5px; text-transform: uppercase; }
.brand span { color: color-mix(in srgb, var(--text) 30%, var(--muted)); }
.theme { margin-left: auto; min-width: 5.5em; }
.help { min-width: 2.2em; font-weight: 600; }
/* looks like the header buttons next to it */
.code-link { display: inline-flex; align-items: center; justify-content: center; align-self: stretch; padding: 0 9px; border: 1px solid var(--line); border-radius: 6px; background: var(--panel); color: var(--muted); }
.code-link:hover { color: var(--text); border-color: var(--muted); }

.site-foot { flex: none; padding: 2px 16px 6px; text-align: center; font-size: 12px; color: var(--muted); }
.site-foot a { color: inherit; }
.site-foot a:hover { color: var(--text); }
.noscript { margin: 0; padding: 8px 16px; text-align: center; font-size: 14px; color: var(--text); border-bottom: 1px solid var(--line); }
.noscript a { color: var(--accent); }

/* keyboard shortcuts; padding sits on the children so a click on the dialog itself is the backdrop */
.help-dlg {
  padding: 0;
  max-width: min(760px, calc(100vw - 32px));
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--edge);
  border-radius: 12px;
}
.help-dlg:focus { outline: none; }
.help-dlg::backdrop { background: rgb(0 0 0 / 0.45); }
.help-head { display: flex; justify-content: space-between; align-items: center; padding: 14px 18px 0; }
.help-head h2 { margin: 0; }
.help-head button { border: none; background: none; font-size: 20px; line-height: 1; padding: 0 4px; color: var(--muted); }
.help-cols { display: flex; flex-wrap: wrap; gap: 8px 36px; padding: 6px 18px 16px; }
.help-cols section { flex: 1 1 300px; }
.help-cols dl { display: grid; grid-template-columns: auto 1fr; gap: 6px 14px; margin: 0; font-size: 13px; }
.help-cols dt { white-space: nowrap; }
.help-cols dd { margin: 0; }
.help-by { margin: 0; padding: 10px 18px 14px; border-top: 1px solid var(--line); font-size: 12px; color: var(--muted); }
.help-by a { color: inherit; }
.help-by a:hover { color: var(--text); }
.tag {
  font-size: 11px;
  font-weight: 400;
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 10px;
  padding: 0 6px;
  margin-left: 4px;
}

select {
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 4px 8px;
}

/* in the source panel, lined up with the fields below */
.paths { display: grid; grid-template-columns: var(--lw) minmax(0, 1fr); gap: 8px; align-items: center; margin-bottom: 8px; }
.paths > .k { white-space: nowrap; }
.paths select { min-width: 0; text-overflow: ellipsis; }
.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip.on, .seg button.on { border-color: var(--accent); color: var(--accent); }
/* spend paths that are meant to fail (wrong signer, timelock not reached) */
.chip.fails { border-style: dashed; }
.seg { display: flex; }
/* neighbours overlap by 1px (one shared border); the active / hovered one is
   drawn on top so its accent border shows on all four sides */
.seg button { border-radius: 0; position: relative; }
.seg button + button { margin-left: -1px; }
.seg button:hover, .seg button.on { z-index: 1; }
.seg button:first-child { border-radius: 6px 0 0 6px; }
.seg button:last-child { border-radius: 0 6px 6px 0; }

.toggle { display: flex; align-items: center; gap: 6px; cursor: pointer; white-space: nowrap; }
.toggles { display: flex; gap: 16px; margin-left: auto; }

.hdr { display: flex; flex: 1; flex-wrap: wrap; align-items: center; gap: 12px 20px; }
/* alt stack column: the alt stack toggle */
body:not(.alt-on) .stackbox.alt-only { display: none !important; }
body.alt-on .stacks { grid-template-columns: minmax(0, 560px) minmax(0, 560px); }

/* script refused: uses the alt stack or test keys while they are off */
body.blocked .stacks,
body.blocked .timeline { display: none; }
.op-title.err { color: var(--fail); }
.op-title.start { color: var(--text); font-style: italic; }



/* layout */

main {
  display: grid;
  grid-template-columns: minmax(300px, 400px) 1fr;
  gap: 12px;
  padding: 12px 16px;
  flex: 1;
  min-height: 0;
  overflow: auto;
}

.left, .center { display: flex; flex-direction: column; gap: 12px; min-width: 0; min-height: 0; }
/* placed over the step card + script + stack cells by the layouts below;
   the panels inside keep --pad (set there) from its edge */
.run-frame { display: none; border: 1px solid var(--edge); border-radius: 14px; background: color-mix(in srgb, var(--panel) 45%, var(--bg)); }
.left .grow { flex: 0 1 auto; min-height: 0; overflow: auto; }

.panel {
  background: var(--panel);
  border: 1px solid var(--edge);
  border-radius: 10px;
  padding: 10px 14px;
}


/* source panel */

.src-head { display: flex; justify-content: space-between; align-items: center; gap: 8px; margin-bottom: 8px; }
.src-head h2 { margin: 0; white-space: nowrap; }
.src-head h2 kbd, .cost-panel h2 kbd { font-weight: 400; letter-spacing: 0; margin-left: 4px; }
/* minmax(0, 1fr): a long unbreakable value (a hex key) must wrap, not widen the panel */
.field { display: grid; grid-template-columns: var(--lw) minmax(0, 1fr); gap: 8px; align-items: center; }
/* source field names: near the size of the values, readable on the dark panel */
.src .paths > .k, .src .field > .k, .src .row > .k { font-size: 14px; color: color-mix(in srgb, var(--text) 75%, var(--muted)); }
/* both fields are editable; only this arrow tells which one is the source */
/* keeps its line when empty: the fields don't jump as the source changes */
.flow { font-size: 12px; line-height: 16px; min-height: 20px; color: var(--text); padding: 2px 0 2px calc(var(--lw) + 8px); }

.src-input {
  width: 100%;
  font: 14px/1.4 var(--mono);
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 6px 9px;
}
/* source fields grow to fit the whole text (height set from app.js);
   policy / miniscript have no spaces, so they may wrap anywhere */
textarea.src-input { display: block; resize: none; overflow: hidden; overflow-wrap: anywhere; }
.field { align-items: start; }
.field > .k { padding-top: 7px; }
.wrap-field { margin-top: 6px; }
.wrap-field > .k { padding-top: 4px; }
.desc-field { margin-top: 6px; }
.wrap-warn { font-size: 12px; color: var(--accent); padding: 4px 0 0 calc(var(--lw) + 8px); }
.desc-sum { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 10px; padding: 4px 0 0 calc(var(--lw) + 8px); font-size: 12px; }
.desc-sum[hidden] { display: none; }
/* copy sits on the descriptor itself: it copies the field (+ checksum), not the line below */
.desc-box { position: relative; min-width: 0; }
.desc-box textarea { width: 100%; box-sizing: border-box; padding-right: 72px; }
.copy-desc { position: absolute; top: 5px; right: 5px; padding: 1px 6px; font-size: 11px; color: var(--muted); }
.copy-desc[hidden] { display: none; }
.desc-sum code { color: var(--text); font-size: 13px; }
/* test keys: the note says it; the checksum itself stays readable */
.sum-note { color: var(--muted); font-style: italic; }
.copied { display: none; color: var(--ok); font-family: var(--mono); overflow-wrap: anywhere; }
.desc-sum.show-copied > * { display: none; }
.desc-sum.show-copied > .copied { display: inline; }
.copied.fail { color: var(--fail); }
.src-input:focus { outline: none; border-color: var(--accent); }
.src-input.invalid { border-color: var(--fail); }
/* a layer this source has none of (a raw script has no policy): faint, still typeable */
.field.absent:not(:focus-within) > .k { color: var(--muted); }
.field.absent:not(:focus-within) .src-input { border-style: dashed; background: transparent; }
.field.absent:not(:focus-within) select { opacity: 0.5; }
.script-field { margin-top: 6px; }
.own-script { padding: 4px 0 0 calc(var(--lw) + 8px); }
.derived-line { display: block; width: 100%; text-align: left; border: 1px dashed var(--line); background: transparent; color: var(--muted); font-size: 12px; padding: 6px 9px; border-radius: 8px; }
.derived-line[hidden], #derived[hidden] { display: none; }
.derived-line span { color: var(--text); margin-left: 6px; }
.src-msg { font-size: 12px; margin: 4px 0; padding-left: calc(var(--lw) + 8px); }
.src-msg:empty { display: none; }
.src-sep { height: 1px; background: var(--line); margin: 10px 0; }
.src-msg.warn { color: var(--fail); }
.src-msg.ok { color: var(--ok); }
.src-msg.busy { color: var(--muted); }

/* select is as wide as its longest option: let it shrink to the panel */

.src .row { display: grid; grid-template-columns: var(--lw) minmax(0, 1fr); gap: 8px; padding: 2px 0; }
.src .row[hidden] { display: none; }
.src code { overflow-wrap: anywhere; }
/* the opcode map wraps at its <wbr> after commas; inside a name only as a last resort */
.src code#miniscript { overflow-wrap: break-word; }
.frag-ops { margin: 2px 0 6px calc(var(--lw) + 8px); font: 12px/1.4 var(--mono); color: var(--k-pubkey); overflow-wrap: anywhere; }
.keys-note { font-size: 12px; color: var(--muted); margin-top: 2px; line-height: 1.4; }
.about { font-size: 12px; color: var(--muted); margin-top: 6px; line-height: 1.4; }
.about[hidden] { display: none; }

.frag { border-radius: 3px; transition: background 0.15s; }
.frag.hover { background: color-mix(in srgb, var(--k-pubkey) 18%, transparent); }
.frag.active > .fh { background: color-mix(in srgb, var(--accent) 30%, transparent); border-radius: 3px; }

/* script listing */

.script { list-style: none; margin: 0; padding: 0; }
.script li {
  display: flex;
  gap: 12px;
  padding: 3px 8px;
  padding-left: calc(8px + var(--depth) * var(--indent, 20px));
  border-radius: 5px;
  border-left: 3px solid transparent;
  cursor: pointer;
}
.script .pc { color: var(--muted); min-width: 1.5em; text-align: right; font-size: 12px; padding-top: 1px; }
.script .op.push { color: var(--k-pubkey); }
/* a long push (a hex key) is cut, the full text is in the title */
.script .op { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.script li.pending { opacity: 0.55; }
.script li.done { opacity: 1; }
.script li.skipped .op { text-decoration: line-through; color: var(--muted); }
.script li.error { background: color-mix(in srgb, var(--fail) 18%, transparent); }
.script li.current { background: color-mix(in srgb, var(--accent) 16%, transparent); border-left-color: var(--accent); opacity: 1; }
/* grouped row: the ops of one leaf fragment; each op dims / strikes / lights on its own */
.script li.group .gops { flex: 1; display: flex; flex-wrap: wrap; gap: 0 0.6em; min-width: 0; }
.script .gop { min-width: 0; max-width: 100%; display: flex; border-radius: 3px; }
.script .gop.pending { opacity: 0.55; }
.script .gop.skipped .op { text-decoration: line-through; color: var(--muted); }
.script .gop.error { background: color-mix(in srgb, var(--fail) 25%, transparent); }
.script .gop.current { background: color-mix(in srgb, var(--accent) 30%, transparent); }
.script.run .gop.current { background: none; }
.script.run li.group.current { background: color-mix(in srgb, var(--accent) 16%, transparent); }
.script li.group.current { background: color-mix(in srgb, var(--accent) 8%, transparent); }
.script-head { display: flex; justify-content: space-between; align-items: baseline; gap: 8px; }
.link-btn { border: none; background: none; padding: 0; font-size: 12px; color: var(--muted); text-decoration: underline dotted; }
.link-btn:hover:not(:disabled) { color: var(--text); }
.script li.hl, .strip li.hl { outline: 1px dashed var(--k-pubkey); outline-offset: -1px; opacity: 1; }
.script li.phase-line { justify-content: center; font-size: 12px; color: var(--k-hash); padding: 6px 8px; }
/* step 0: before the first opcode, the witness is the stack */
.script li.start-line .op, .strip li.start { color: var(--muted); font-style: italic; }
.script li.start-line.current .op, .strip li.start.current { color: var(--text); }
.script li.start-line.current { background: color-mix(in srgb, var(--text) 8%, transparent); border-left-color: var(--text); border-left-style: dashed; }
.strip li.start.current { border-color: var(--text); background: color-mix(in srgb, var(--text) 8%, transparent); }
/* strip: start is not an opcode - dashed, no fill, set apart from the first op */
.strip li.start { border-style: dashed; background: transparent; margin-right: 8px; }

/* script strip (phone): the script as a column next to the stack */

.strip-panel, .fold { display: none; }
.bench { display: contents; }
.fold { margin-left: auto; flex: none; font-size: 12px; padding: 2px 8px; }
.strip {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  max-height: 30vh;
  overflow: auto;
  font: 13px/1.3 var(--mono);
}
.strip li {
  padding: 2px 6px;
  border-radius: 5px;
  border: 1px solid var(--line);
  cursor: pointer;
}
.strip li.push { color: var(--k-pubkey); }
.strip li.ctl { color: var(--k-hash); }
.strip li.phase { flex-basis: 100%; border: 0; text-align: center; font-size: 11px; color: var(--k-hash); padding: 0; }
.strip li.pending { opacity: 0.55; }
.strip li.skipped { text-decoration: line-through; color: var(--muted); }
.strip li.error { border-color: var(--fail); background: color-mix(in srgb, var(--fail) 18%, transparent); }
.strip li.current { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 16%, transparent); opacity: 1; }

/* explanation */

.op-line { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 12px; }
.op-title { font-size: 18px; font-weight: 700; color: var(--accent); }
.desc { color: var(--muted); }
.more { display: none; }
.note, .err { margin-top: 4px; }
.note { font-family: var(--mono); }
.err { font-family: var(--mono); color: var(--fail); }

.delta { display: flex; flex-wrap: wrap; align-items: center; gap: 5px; margin-top: 6px; }
.delta .k:not(:first-child) { margin-left: 4px; }
.chipx {
  font: 600 12px var(--mono);
  color: var(--kind);
  padding: 1px 7px;
  border-radius: 5px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--kind);
}
.chipx.gone { opacity: 0.6; text-decoration: line-through; }

/* stacks */

.stacks { flex: 1; min-height: 0; display: grid; grid-template-columns: minmax(0, 560px); gap: 12px; }
.stackbox { display: flex; flex-direction: column; min-height: 0; align-self: start; max-height: 100%; }

/* the stack is drawn as an open-top container: items rest on its floor.
   Height = deepest point of the run (--rows, set in app.js); it shrinks and
   scrolls when the screen is too short */
.well {
  flex: 0 1 auto;
  height: calc(var(--rows, 4) * 39px + 20px);
  min-height: 100px;
  overflow-y: auto;
  overflow-x: hidden; /* popped items slide out sideways: no scrollbar flash */
  display: flex;
  flex-direction: column;
  padding: 10px;
  border: 2px solid var(--line);
  border-top: 0;
  border-radius: 0 0 12px 12px;
  background: var(--bg);
}
.stack { --gap: 5px; display: flex; flex-direction: column; gap: var(--gap); margin-top: auto; }

.empty-stack {
  color: var(--muted);
  padding: 14px;
  text-align: center;
}

.item {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 4px 12px;
  flex-wrap: wrap;
  padding: 6px 10px;
  border-radius: 8px;
  border: 1px solid var(--line);
  border-left: 4px solid var(--kind);
  background: var(--panel);
}
.item .lbl { font-weight: 600; color: var(--kind); min-width: 0; max-width: 100%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.item .hex { font-size: 11px; color: var(--muted); }
.item .size { opacity: 0.7; }

.k-sig { --kind: var(--k-sig); }
.k-pubkey { --kind: var(--k-pubkey); }
.k-hash { --kind: var(--k-hash); }
.k-num { --kind: var(--k-num); }
.k-script { --kind: var(--k-hash); }

/* one step forward: popped items turn red, hold, then slide out and collapse
   (.leaving); pushed ones drop in after them (.enter.after-pop) */
/* timing knobs: popped leave over --t-leave, pushed start at --t-push-delay */
.stack { --t-leave: 0.85s; --t-push-delay: 0.65s; --t-push: 0.5s; }
.item.new { box-shadow: 0 0 0 1px var(--kind); }
.item.enter { animation: push var(--t-push) ease-out; }
.item.enter.after-pop { animation-delay: var(--t-push-delay); animation-fill-mode: backwards; }
.item.leaving {
  overflow: hidden;
  border-color: var(--fail);
  background: color-mix(in srgb, var(--fail) 14%, var(--panel));
  animation: leave var(--t-leave) ease-in forwards;
}
.item.leaving .lbl { color: var(--fail); text-decoration: line-through; }

@keyframes push {
  from { transform: translateY(-14px); opacity: 0; }
  to { transform: none; opacity: 1; }
}
@keyframes leave {
  0%, 45% { opacity: 1; transform: none; max-height: 60px; }
  100% { opacity: 0; transform: translateX(70%); max-height: 0; padding-top: 0; padding-bottom: 0; border-top-width: 0; border-bottom-width: 0; margin-bottom: calc(-1 * var(--gap)); } /* cancels the flex gap */
}

@media (prefers-reduced-motion: reduce) {
  .item.enter { animation: none; }
  .item.leaving { display: none; }
}

/* step bar */

.stepbar {
  border-bottom: 1px solid var(--line);
  padding: 8px 16px;
}

.controls { display: flex; align-items: center; gap: 8px 10px; flex-wrap: wrap; }
.play { min-width: 2.6em; }
.play.on { border-color: var(--accent); color: var(--accent); }
.counter { min-width: 6.5em; font-family: var(--mono); font-size: 12px; }
.result { margin-left: auto; font-family: var(--mono); }
.result.ok { color: var(--ok); }
.result.fail { color: var(--fail); }

.timeline { flex: 1; min-width: 120px; display: flex; align-items: flex-end; gap: 3px; height: 30px; }
.tick {
  flex: 1 1 0;
  min-width: 0; /* long scripts: ticks shrink instead of overflowing a phone */
  max-width: 26px;
  height: 100%;
  display: flex;
  align-items: flex-end;
  padding: 2px;
  border-radius: 4px;
}
.tick span { display: flex; flex-direction: column-reverse; gap: 1px; width: 100%; }
.timeline.dense .tick span { gap: 0; }
.tick i { flex: 1 1 0; min-height: 0; background: var(--kind, var(--muted)); border-radius: 1px; opacity: 0.75; }
.tick.skipped span { opacity: 0.3; }
.tick.error { border-color: var(--fail); }
.tick.current { border-color: var(--accent); }
.tick.current i { opacity: 1; }
/* start is the state before the run, not a step: dashed, neutral, set apart */
.tick.start { border: 1px dashed var(--edge); margin-right: 6px; }
.tick.start.current { border-color: var(--text); }

/* desktop explore: source | script | stack, the step card over script and
   stack. The listing and the stack are as tall as their content, up to the
   window bottom, then they scroll inside themselves. .left / .center / .bench dissolve into the grid.
   On very wide screens everything is centered at --page width */
@media (min-width: 861px) {
  /* = the explore columns at their widest (460 + 560 + 480) + gaps + padding:
     the header lines up with the panels */
  :root { --page: 1556px; }
  .brand { font-size: 24px; letter-spacing: 2px; }
  /* the toggles, moved here from the header by app.js; inside an h2 they drop its caps */
  .toggle-slot { font-size: 13px; font-weight: 400; color: var(--text); text-transform: none; letter-spacing: 0; }
  .stackbox h2 { display: flex; align-items: center; gap: 6px; }
  .stackbox h2 .toggle-slot { margin-left: auto; }
  .keys-slot { padding: 0 0 8px calc(var(--lw) + 8px); }
  .path-row { display: none; }
  /* panel titles: a bar across the panel, ruled off from the content */
  .panel > h2, .src-head, .script-head { margin: -2px -14px 10px; padding: 0 14px 8px; border-bottom: 1px solid var(--line); }
  .panel > h2, .src-head h2, .script-head h2 { color: color-mix(in srgb, var(--text) 70%, var(--muted)); }
  .script-head h2 { margin: 0; }
  /* branches (IF / ELSE) stand out in the listing */
  .script { --indent: 32px; }
  /* room to spare: taller ticks so the mini stacks read */
  .timeline { height: 56px; gap: 4px; }
  .tick { max-width: 40px; }
  /* --edge, not --line: on the run frame's tinted background a --line border vanishes */
  .controls > button { height: 48px; min-width: 52px; font-size: 18px; border-color: var(--edge); }
  .counter { font-size: 14px; }
  header { padding-inline: max(16px, calc((100% - var(--page)) / 2 + 16px)); }
  main.explore {
    /* the stack column is only as wide as the stack, so the step card above
       ends where the stack does; the script column takes the rest */
    grid-template-columns: minmax(300px, 460px) minmax(220px, 560px) minmax(260px, 480px);
    /* row 2 is as tall as its content, at most what the window leaves: the
       frame ends under the tallest panel, and long ones scroll inside */
    grid-template-rows: auto auto minmax(0, auto) 1fr;
    align-content: start;
    /* the last row is empty on the right: a left column taller than the run grows it,
       instead of stretching the step card and the panels */
    grid-template-areas: 'src player player' 'src explain explain' 'src script stack' 'src . .';
    /* the script column stops at 560px: spare width goes to both sides, not into the listing */
    justify-content: center;
    width: 100%;
    max-width: var(--page);
    margin: 0 auto;
    box-sizing: border-box;
  }
  main.explore .left, main.explore .center { display: contents; }
  main.explore .src-col { grid-area: src; align-self: start; box-sizing: border-box; display: flex; flex-direction: column; gap: 12px; }
  /* as tall as the script, up to the window bottom, then it scrolls */
  main.explore .left .grow { grid-area: script; align-self: stretch; max-height: calc(100% - var(--pad)); margin: 0 0 var(--pad) var(--pad); box-sizing: border-box; }
  main.explore .explain { grid-area: explain; margin: 0 var(--pad); }
  /* the player is the run frame's top row: it steps what is below it */
  main.explore .stepbar { grid-area: player; margin: var(--pad) var(--pad) 0; padding: 0; border: 0; }
  /* the stack is as tall as the run's deepest point (--rows, app.js), not the
     whole column: a huge well reads badly */
  main.explore .stacks { grid-area: stack; align-self: start; max-height: calc(100% - var(--pad)); margin: 0 var(--pad) var(--pad) 0; grid-template-columns: minmax(0, 1fr); }
  body.alt-on main.explore { grid-template-columns: minmax(300px, 460px) minmax(220px, 560px) minmax(420px, 972px); }
  /* grouped rows (pkh(C) = 5 ops) want a wider listing than one op per line */
  body.script-grouped main.explore { grid-template-columns: minmax(300px, 460px) minmax(380px, 560px) minmax(260px, 480px); }
  body.script-grouped.alt-on main.explore { grid-template-columns: minmax(300px, 420px) minmax(380px, 560px) minmax(400px, 972px); }
  /* the alt stack as wide as the stack: 2 x 480 + gap at most */
  body.alt-on main.explore .stacks { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
  /* one height for every example (the deepest, P2WSH, needs 9 rows with the
     spare one): switching examples must not resize the stack; only a deeper
     custom script makes it taller */
  main.explore .well { height: calc(max(var(--rows, 4), 9) * 39px + 20px); }
  main.explore { --pad: 8px; }
  main.explore .run-frame { display: block; grid-area: 1 / 2 / 4 / 4; }
}

/* touch screens: no keyboard, so header hotkey hints only take room */
@media (pointer: coarse) {
  header kbd, #explain kbd, .src-head kbd, .help { display: none; }
}

@media (max-width: 860px) {
  body { height: auto; min-height: 100vh; }
  /* align-content: start - short content must not stretch the rows */
  main { grid-template-columns: minmax(0, 1fr); overflow: visible; align-content: start; }
  .stackbox { max-height: none; }
  .hdr { gap: 10px; }
  .controls > button { padding: 8px 11px; }
  /* step bar is a footer on phones: last in body's flex column, stuck to the
     bottom edge; step buttons are its bottom row, nearest the thumb */
  .stepbar {
    position: sticky;
    bottom: 0;
    z-index: 2;
    order: 1;
    background: var(--bg);
    border-bottom: 0;
    border-top: 1px solid var(--line);
    padding-bottom: max(8px, env(safe-area-inset-bottom));
  }
  .timeline { flex-basis: 100%; order: -1; }
  /* folded source: the head's margin is gone, the spend path keeps its distance */
  body.src-folded .paths { margin: 8px 0 0; }
  :root { --lw: 92px; }
  .site-foot { display: none; }
  /* a sideways swipe must not turn into the browser's back / forward gesture */
  html, body { overscroll-behavior-x: none; }
  .stepbar { touch-action: pan-x pan-y; }
  /* inside main now: last grid row, out to the screen edges over main's padding */
  main.explore .stepbar { grid-area: 4 / 1; margin: 0 -16px -12px; }
  .toggles { margin-left: 0; }
  /* theme button: icon only, flows into the mode row instead of squeezing it */
  .hdr { display: contents; }
  .theme { min-width: 0; }
  .theme-name { display: none; }
  /* no alt stack on phones (app.js): no toggle either */
  .toggle.alt-only { display: none !important; }
  /* explore order: source, step card, then script | stack side by side;
     .left / .center dissolve into main's grid */
  .left, .center, .src-col { display: contents; }
  .spend-panel, .cost-panel, .limits-panel { display: none; }
  /* explicit rows: the frame's cells must not push the others down in auto placement */
  .src { order: 1; grid-area: 1 / 1; }
  .explain { order: 2; grid-area: 2 / 1; margin: var(--pad) var(--pad) 0; }
  main.explore { --pad: 6px; }
  main.explore .run-frame { display: block; grid-area: 2 / 1 / 4 / 2; }
  /* the bench's height is set by the stack (or its min-height), never by the
     script: the strip is absolutely placed and scrolls inside itself */
  .bench { display: grid; order: 3; grid-area: 3 / 1; grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr); gap: 8px; min-height: 300px; margin: 0 var(--pad) var(--pad); }
  /* the bench takes whatever height is left above the footer (at least 300px) */
  main.explore { grid-template-rows: auto auto minmax(300px, 1fr); align-content: stretch; }
  /* the stack fills its column: as tall as the script next to it, so it
     scrolls only when the run is deeper than the bench (then the bench grows) */
  .bench .stacks { align-self: stretch; grid-template-rows: minmax(0, 1fr); }
  .bench .stackbox { align-self: stretch; }
  .strip-panel { display: block; position: relative; padding: 0; }
  .strip { position: absolute; inset: 0; max-height: none; padding: 6px; flex-direction: column; flex-wrap: nowrap; gap: 2px; }
  .strip { overflow-x: hidden; }
  /* a listing, not tokens: only the start, the current op and an error get a frame */
  .strip li { flex: none; padding: 1px 6px 1px calc(6px + var(--depth, 0) * 10px); border-color: transparent; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
  .strip li.start { border-color: var(--line); }
  .strip li.start { margin: 0 0 4px; }
  .strip li.phase { flex-basis: auto; padding: 2px 0; }
  /* the column next to the stack is the script on phones: no second listing */
  .left .grow { display: none; }
  /* labels are enough on a narrow stack; unnamed data is labelled by its short hex */
  .item .hex { display: none; }
  .fold { display: inline-block; }
  body.src-folded .src-body { display: none; }
  body.src-folded .src-head { margin-bottom: 0; }
  main.explore { touch-action: pan-y; }
  /* step card, script and the whole stack on one screen: compact
     stack rows, no spare row in the well, no timeline in the footer
     (swipes and buttons step; the ticks are too small for a finger) */
  .stepbar .timeline { display: none; }
  .result .msg { display: none; }
  /* fixed heights within one example: stepping must not move the stack.
     The step card and the strip scroll inside themselves when text is long */
  #explain { height: 110px; overflow-y: auto; }
  #explain:not(.expanded) .desc { display: -webkit-box; -webkit-line-clamp: 1; -webkit-box-orient: vertical; overflow: hidden; cursor: pointer; }
  /* ▾ / ▴ next to a cut-off description: it can be tapped open */
  #explain .op-line { display: grid; grid-template-columns: minmax(0, 1fr) auto; column-gap: 8px; }
  #explain .op-title { grid-column: 1 / -1; }
  #explain.clamped .more, #explain.expanded .more { display: block; color: var(--accent); cursor: pointer; }
  #explain.clamped .more::before { content: '▾'; }
  #explain.expanded .more::before { content: '▴'; }
  main.explore { gap: 8px; padding-top: 8px; }
  .stack { --gap: 3px; }
  .item { padding: 3px 8px; }
  /* row = item (~28.3px) + 3px gap, rounded up; + padding 12px + bottom border 2px */
  .well { height: auto; flex: 1 0 auto; min-height: calc((var(--rows, 4) - 1) * 32px + 14px); padding: 6px; }
  .stackbox h2 { margin-bottom: 4px; }
  .empty-stack { padding: 6px; }
  .stackbox { padding: 8px 10px 4px; }
}

/* the input as sent, cost and limits (desktop, under the source) */
body.no-cost :is(.spend-panel, .cost-panel, .limits-panel), body.blocked :is(.spend-panel, .cost-panel, .limits-panel) { display: none; }
.spend-items { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 4px; }
.spend-items li { display: grid; grid-template-columns: 22px minmax(0, 1fr) auto; align-items: center; gap: 8px; font-size: 13px; }
.spend-i { color: var(--muted); font: 11px var(--mono); text-align: right; }
.spend-b { color: var(--muted); font: 12px var(--mono); }
.spend-items .chipx { justify-self: start; }
.spend-items li.is-script .chipx { border-style: dashed; }
.spend-note { grid-column: 2 / -1; font-size: 12px; color: var(--muted); font-style: italic; }
.spend-size { margin-top: 8px; font-size: 13px; color: var(--muted); }
.spend-size b { color: var(--text); font-family: var(--mono); font-weight: 600; }
.cost { width: 100%; border-collapse: collapse; font-size: 13px; }
.cost th { text-align: right; font-weight: 600; color: var(--muted); font-size: 12px; padding: 2px 6px; cursor: help; }
.cost th:first-child { text-align: left; }
.cost td { text-align: right; padding: 3px 6px; font-family: var(--mono); }
.cost td.cost-name { text-align: left; font-family: inherit; }
.cost tbody tr { cursor: pointer; }
.cost tbody tr:hover { background: color-mix(in srgb, var(--text) 6%, transparent); }
.cost tbody tr.current { background: color-mix(in srgb, var(--accent) 14%, transparent); }
.cost .ok { color: var(--ok); }
.cost .fail { color: var(--fail); }
.limits { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 3px; font-size: 13px; }
.limits li { display: grid; grid-template-columns: minmax(0, 1fr) auto 76px; gap: 8px; }
.lim-v { font-family: var(--mono); text-align: right; }
.lim-rule { font-size: 11px; color: var(--muted); text-align: right; }
.limits li.over .lim-v, .limits li.over span:first-child { color: var(--fail); }