:root {
  --view-gap: 12px;  /* the view's boxes from its edges (player, display, hint), a fit's margin too (see viewFor) */
  --player-width: calc(6 * 48px + 5 * 6px);  /* the player's six buttons and their gaps (a .row's): the folded bar's inner width */
  --bg: #0e1116;
  --panel: #161b22;
  --border: #2a313c;
  --text: #e6edf3;
  --muted: #8b949e;
  --accent: #f0b429;
  --accent-text: #1a1300;
  --grid: rgba(255, 255, 255, 0.06);
  --box: rgba(14, 17, 22, 0.75);  /* the boxes over the view */
  --pick: color-mix(in srgb, rgb(240 180 41) 14%, var(--panel));  /* a choice picked, a switch's hover: the gold on the panel, opaque */
  --pick-strong: color-mix(in srgb, rgb(240 180 41) 32%, var(--panel));  /* (the same whatever lies under it: a box over the sky too) */
  --motif: #bc8cff;  /* a grid's motif, outlined while its size is hovered (see drawMotif), its words in the size's tooltip */
  --face: #e5484d;  /* a solid's face round it */
  --sector: #58a6ff;  /* a face's sector round it (a dodecahedron's pentagon, 5 triangles) */
  --cell: #3fb950;  /* a cell of the motif, when it has several (a triangle's 3 kites) */
  color-scheme: dark;
}
/* Light theme (Display box: Light, or System on a light system; see applyTheme) */
:root[data-theme="light"] {
  --bg: #f6f8fa;
  --panel: #ffffff;
  --border: #d0d7de;
  --text: #1f2328;
  --muted: #656d76;
  --accent: #bf8700;
  --accent-text: #ffffff;
  --grid: rgba(0, 0, 0, 0.08);
  --box: rgba(255, 255, 255, 0.82);
  --pick: color-mix(in srgb, rgb(240 180 41) 8%, var(--panel));
  --pick-strong: color-mix(in srgb, rgb(240 180 41) 22%, var(--panel));
  --motif: #8250df;
  --face: #c4161c;
  --sector: #0969da;
  --cell: #2da44e;
  color-scheme: light;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font: 14px/1.4 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

body { display: flex; flex-direction: column; font-variant-numeric: tabular-nums; }  /* every digit as wide as the others, everywhere: numbers that change (a step, a count) never jump */

header { padding: 0; border-bottom: 1px solid var(--border); }  /* one hairline, edge to edge, under the tabs: the first and the last at its edges */
/* the tabs at the very top on the left, on a hairline; the app's tab on the right */
.header-row { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.header-end { display: flex; align-self: stretch; align-items: center; gap: 12px; }
.header-end .max-steps { margin: 0; width: 176px; flex: none; }  /* the length asked: one width whatever it says (see compactCount) */
.header-end .max-steps .field input { padding-right: 32px; }  /* (room for its unit, inside its box) */
.header-end .max-steps .field input:not(:focus) { text-align: right; }  /* (its number against its unit; typed, as any field) */
.max-steps .steps-glyph { position: absolute; right: 10px; top: 50%; transform: translateY(-50%); display: flex; font-size: 20px; line-height: 1; color: var(--accent); pointer-events: none; }  /* its unit, steps, in its words' gold */
.max-steps .field:focus-within .steps-glyph { display: none; }  /* (typing: the number alone, Enter's ↵ there) */
.bar-sub .pi { color: var(--accent); }
.bar-sub .walking { color: var(--text); font-weight: 600; }  /* an automaton: what seeds it */

main { flex: 1; display: flex; min-height: 0; }

.panel {
  width: 280px;
  flex-shrink: 0;
  overflow-y: auto;
  scrollbar-gutter: stable;          /* keep room for the scrollbar: the column never shifts */
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
  background: var(--panel);
  border-right: 1px solid var(--border);
  padding: 0 12px 4px 16px;
}
.panel::-webkit-scrollbar { width: 8px; }
.panel::-webkit-scrollbar-track { background: transparent; }
.panel::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
.panel::-webkit-scrollbar-thumb:hover { background: var(--muted); }
.panel section { padding: 12px 0; border-top: 1px solid var(--border); }  /* a grey hairline between sections */
#paramsPane > section:first-child, #galleryPane > section:first-child, #yourList > section:first-child { padding-top: 6px; border-top: 0; }  /* the first, always there: no line, no gap under the header */
:is(#paramsPane, #galleryPane, #yourList) > section:first-child h2 { margin-top: 0; }  /* its title as high in every pane */
.row-act { margin-left: auto; padding: 0 6px; font-size: 16px; color: var(--muted); border-radius: 4px; }  /* a row's action at its end: × on a saved setup */
:not(:hover) > .row-act { visibility: hidden; }  /* (shown while its row is hovered, its place kept) */
.row-act:hover { color: var(--text); background: var(--border); }
.panel .muted:empty { display: none; }  /* an empty status line takes no room */
/* a section's title: its gold picture, then its name; a sub-section's (field-label): semibold */
h2 { display: flex; align-items: center; gap: 7px; margin: 2px 0 10px; font-size: 14px; font-weight: 600; color: var(--text); }
h2 .icon { width: 24px; height: 24px; flex: none; color: var(--accent); vertical-align: 0; }
/* a section's own action, on its title's right (How it works, Copy RLE, Full number) */
.head-btn { margin-left: auto; display: inline-flex; align-items: center; gap: 4px; padding: 3px 8px; font-size: 12px; font-weight: 500; border-radius: 6px; }
.head-btn .icon { width: 14px; height: 14px; color: inherit; }

/* Walk: Grid or Cells, beside the heading */
.walk-head { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.walk-head h2 { flex: 1; margin: 0; }

label { display: block; margin-bottom: 10px; }
label.check { display: flex; align-items: center; gap: 8px; }
label.check { }
label.check:has(input:disabled) { opacity: 0.4; cursor: default; }  /* shown, but of no use here */

input[type=number], input[type=text], select, textarea {
  display: block;
  width: 100%;
  margin-top: 4px;
  padding: 6px 8px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  font: inherit;
}
/* the formula, like the number of digits under it: a field that looks like a label until it
   is hovered or used; in yellow bold when it is the number chosen (no card matches it) */
/* a value of one's own, in yellow bold: a formula no card matches, a rule no preset matches */
.field :is(input, textarea).custom { color: var(--accent); font-weight: 600; }
.field input.battle-formula { color: var(--walker); font-weight: 700; }  /* a battle's formula, its battle built with it: bold in its walker's colour (over .custom's yellow) */
textarea { resize: none; line-height: 1.35; }  /* (Text's lines, a new line by Enter) */
.field textarea { height: 200px; }  /* (fixed, as a line's 34 px: edited or not, whatever its font; more lines scroll) */
.field textarea:not(:focus) { font-family: var(--face, inherit); }  /* at rest, in the font it is drawn in (see TEXT_FONTS) */
.font-pic { font-size: 18px; font-weight: 700; line-height: 22px; }  /* a font's tile: Aa in it */
input[type=range] { width: 100%; accent-color: var(--accent); }
.shape-slider { display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--muted); }  /* Flat ── Inflated: a surface's form */
.shape-slider input { flex: 1; min-width: 0; }
.notch-row { display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--muted); margin-bottom: 10px; }  /* a notched slider: Cut, Area (see notchRow) */
.notch-row .field-label { margin: 0; color: var(--text); }  /* (its title a sub-section's, as Cells', on its row) */
.notch-row .size-gauge { flex: 1; min-width: 0; margin: 0; }
.notch-row .notch-name { min-width: 3.5em; }
/* checkboxes as switches (iOS style): a pill whose knob slides to the right, yellow when on */
input[type=checkbox] {
  appearance: none;
  position: relative;
  flex: none;
  width: 30px;
  height: 18px;
  margin: 0;
  border-radius: 9px;
  background: var(--border);
  cursor: pointer;
  transition: background 0.15s;
}
input[type=checkbox]::before {
  content: '';
  position: absolute;
  top: 2px;
  left: 2px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: #fff;
  transition: transform 0.15s;
}
input[type=checkbox]:disabled { cursor: default; }
input[type=checkbox]:checked { background: var(--accent); }
input[type=checkbox]:checked::before { transform: translateX(12px); }

/* the icons drawn in main.js (3.3): lines in the text's colour, "f" parts filled */
.icon { width: 1.15em; height: 1.15em; vertical-align: -0.2em; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.icon .f { fill: currentColor; stroke: none; }
.icon .thin { stroke-width: 1.1; }
button:has(.icon) { display: inline-flex; align-items: center; justify-content: center; gap: 6px; }

button {
  padding: 6px 12px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  font: inherit;
  cursor: pointer;
}
button:hover:not(:disabled) { border-color: var(--muted); }
button:disabled { opacity: 0.45; cursor: default; }
button.primary {
  width: 100%;
  background: var(--accent);
  color: var(--accent-text);
  border-color: var(--accent);
  font-weight: 600;
}
.row { display: flex; gap: 6px; margin-bottom: 10px; }
.field-label { margin-bottom: 4px; font-size: 12px; font-weight: 600; }  /* a sub-section's title; under it, grey labels (Birth, Survive…) */
.field-label.with-btn { display: flex; align-items: center; }  /* its button on its right (Full number: a head-btn) */
.stepper { display: flex; align-items: center; gap: 6px; margin-bottom: 10px; }
/* a size among the usual ones, across: the browser's slider in the page's gold (as the old seek bar, Flat ↔ Rolled), its
   knob the size in use, a notch each under it (see sizeGauge), inset by the knob's half, where its middle goes */
.size-gauge { margin: -6px 0 12px; }
.size-gauge input { display: block; margin: 0; cursor: pointer; }
.size-gauge .notches { display: flex; justify-content: space-between; padding: 0 7px; margin-top: -2px; }
.size-gauge .notches span { width: 2px; height: 5px; background: var(--muted); border-radius: 1px; }
.stepper span small { display: block; font-size: 11px; font-weight: 400; color: var(--muted); line-height: 1.2; }  /* a size: what to picture, then its tiles */
.stepper span, .stepper input { flex: 1; text-align: center; color: var(--accent); font-weight: 600; white-space: nowrap; }  /* the setup at a glance */
/* the number of digits can be typed: a field that looks like the label until it is hovered or used */
#loopLabel { color: var(--text); }
#loopLabel.on { color: var(--accent); }
.stepper input { min-width: 0; margin: 0; padding: 6px 8px; cursor: text; }
/* the two fields and the − / + buttons: one height, whatever the font (monospace while editing) */
#formula, .field input, .stepper button { height: 34px; }
/* ↵ at the end of a field being edited: clicking it leaves the field, which computes */
.field { position: relative; display: block; }
.formula-field { margin-bottom: 10px; }
.field :is(input, textarea) { margin: 0; }
.stepper .field { flex: 1; min-width: 0; }
.field .enter { display: none; position: absolute; right: 4px; top: 4px; width: auto; height: 26px; padding: 0 8px; border: 0; background: none; color: var(--muted); font-weight: 400; }  /* not the 36 px of the − / + buttons, nor the bold of the digits row */
.field .enter:hover { color: var(--accent); }
.field:focus-within .enter { display: block; }
.field :is(input, textarea):focus { padding-right: 32px; }
/* Every edited field (the formula, the number of digits, the start, Text's lines, the rules): outlined like
   the choice buttons, from the left, and edited alike, in plain monospace on a yellow-framed field, ↵
   at its end; the steppers' (digits, start) centred at rest, written out ("20,000 digits") */
.field :is(input, textarea) { background: transparent; border-color: var(--border); text-align: left; }
.stepper .field input:not(:focus) { text-align: center; }
.field :is(input, textarea):hover { border-color: var(--muted); }
.field :is(input, textarea):focus {
  outline: none;
  text-align: left;
  border-color: var(--accent);
  background: var(--bg);
  color: var(--text);
  font: 400 13px ui-monospace, "SF Mono", Menlo, monospace;
}
.field textarea, .field textarea:focus { text-align: center; }  /* (Text's lines centred, as drawn: after the fields' left) */
.stepper button { width: 36px; padding: 5px 0; }
button.wide { width: 100%; margin-bottom: 10px; }
button.wide.how-it-works { margin-bottom: 4px; }  /* on its rules' first card, the list's gap */
#huntRow .nav-shapes, #galleryTools, #ruleTabs { margin-bottom: 4px; }  /* a wide button right under its tiles (Hunt, Confirm erase, How it works), as close as a row of them */

/* Walk mode: one tab per category, then every choice of that category */
/* Tabs: text only, the active one in yellow and underlined on the header's hairline; always bold,
   so the active tab keeps its width */
.tabs { display: flex; flex-wrap: wrap; gap: 0; align-self: stretch; }  /* (no gap: the underlines meet, tab to tab; the 4px between the words in their padding) */
.tabs button {
  padding: 14px 14px 11px;
  margin-bottom: -1px;               /* the underline covers the hairline */
  background: none;
  border: 0;
  border-bottom: 3px solid transparent;
  border-radius: 0;
  color: var(--muted);
  font-size: 15px;
  font-weight: 600;
  white-space: nowrap;
}
.tabs button:hover:not(.active) { color: var(--text); border-bottom-color: var(--border); }
.tabs button.active { color: var(--accent); border-bottom-color: var(--accent); }
.tabs button .icon { width: 24px; height: 24px; vertical-align: -0.35em; }  /* the tabs' pictures, as the sections' */
.block-label { margin: 2px 0 4px; font-size: 11px; color: var(--muted); }  /* a block of shapes' title: Surface, Tiles of the torus */
.nav-shapes > .block-label { grid-column: 1 / -1; margin: 0; }  /* a group's title among the shapes, across its row: where Surface's is (its margin over it one with the tabs'), the grid's gap under it */
.nav-shapes > .block-label:not(:first-child) { margin-top: 8px; }  /* (the next groups: a little apart) */
.nav-shapes { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 4px; margin-bottom: 10px; }  /* the shapes, 4 a row */
.nav-shapes button { display: flex; flex-direction: column; align-items: center; gap: 2px; padding: 6px 1px; font-size: 10px; background: var(--panel); color: var(--muted); min-width: 0; }
.nav-shapes button span { max-width: 100%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.nav-shapes button svg { width: 24px; height: 24px; }
/* icons: 24 px in a tile, a tab or by a section's title, 20 px on a card, 16 px in a line of text */
/* a group of tiles, one choice among them: joined in one frame, 2 or 3 columns of tiles */
.tile-group { display: flex; grid-column: span 2; }
.tile-group:has(> :nth-child(3 of :not([hidden]))) { grid-column: span 3; }  /* (its buttons shown only: a group's hidden ones never count) */
.tile-group:has(> :nth-child(4 of :not([hidden]))) { grid-column: span 4; }
.tile-group.wide { grid-column: 1 / -1; }  /* a section's big choice: across its row, its buttons as wide as it shares (2, 3 or 4) */
:not(.nav-shapes) > .tile-group { margin-bottom: 10px; }  /* (in a section's flow, not a grid of tiles: spaced as a wide button) */
.tile-group > button { flex: 1 1 0; border-radius: 0; }
.tile-group.text-tabs > button { min-width: 0; padding: 6px 2px; }  /* tabs of words only (the Number's): each its share, as tiles, whatever its word */
.tile-group > button:nth-child(n + 2 of :not([hidden])) { margin-left: -1px; }  /* one line between them */
.tile-group > button:nth-child(1 of :not([hidden])) { border-radius: 6px 0 0 6px; }
.tile-group > button:nth-last-child(1 of :not([hidden])) { border-radius: 0 6px 6px 0; }
.tile-group > button:nth-child(1 of :not([hidden])):nth-last-child(1 of :not([hidden])) { border-radius: 6px; }  /* (one shown alone: round all round) */
.tile-group > button.active, .tile-group > button:hover { position: relative; z-index: 1; }  /* its border over its neighbour's (every button its own layer: above the next one) */
button.switch:hover:not(:disabled) { background: var(--pick); }  /* a switch (a button that a click changes again) answers the hover: off, in the pale gold of a choice picked; on, deeper (Dawn sky) */
button.switch.active:hover:not(:disabled) { background: var(--pick-strong); }
#yourList { display: contents; }  /* (its sections the pane's, as Life's: see .panel section) */
.cell-modes button svg { width: 24px; height: 24px; border-radius: 3px; }  /* the looks of a walk on cells: swatches */
.nav-shapes button.active, .tile-group > button.active { border-color: var(--accent); color: var(--accent); background: var(--pick); }
.mode-list { display: flex; flex-direction: column; gap: 4px; margin-bottom: 10px; }
.mode-list button {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr) auto;  /* one icon column for every list, wide enough for ζ(3) or 16/9; the words shrink; the base's bubble or the × */
  align-items: center;
  gap: 8px;
  padding: 5px 8px;
  text-align: left;
  line-height: 1.25;
  background: var(--panel);
}
.mode-list button:hover { background: var(--bg); }
.mode-icon { font-size: 15px; color: var(--muted); text-align: center; }
.mode-icon svg { width: 20px; height: 20px; }  /* every card's picture alike: a rule's, a Gallery setup's shape, a hunt's find, a battle's way (see card) */
.mode-head { display: flex; align-items: center; justify-content: space-between; gap: 6px; min-width: 0; }  /* a card's name, its base at its right (see cardWords) */
.mode-name { display: block; min-width: 0; font-size: 13px; font-weight: 600; }
.mode-detail { display: block; font-size: 11px; font-weight: 400; color: var(--muted); }
.mode-name, .mode-detail { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }  /* one line each, … when too long (in full on hover) */
/* a bubble, every one: a base's (the rules' cards, Grid | Cells, the bar), a rule's, a loop's, Full number's */
.bubble { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 11px; font-weight: 400; padding: 1px 8px; border: 1px solid var(--border); border-radius: 999px; color: var(--muted); }
.bubble.loop { border-color: rgba(240, 180, 41, 0.5); color: var(--accent); }
button.bubble { background: none; }  /* a bubble to click: a rule's (how it works), a base's (the number) */
button.bubble, .bubble.act { cursor: pointer; }
button.bubble:hover, .bubble.act:hover { color: var(--text); border-color: var(--muted); }
button.active .bubble { color: var(--accent); border-color: var(--accent); }  /* (in a card picked) */
.bubble.active, button.active .bubble.active { background: var(--accent); border-color: var(--accent); color: var(--panel); }  /* (lit, filled gold: the number shown, its base's; how a rule works, shown) */
.mode-head .bubble, .mode-list .bubble { flex-shrink: 0; }  /* (a card's: whole) */
.mode-list .bubble { align-self: start; }  /* (at the card's top right) */
.with-btn > .bubble { margin-left: auto; }  /* (Full number's, at the Formula's right) */
.mode-icon.act { align-self: stretch; display: grid; place-items: center; border-radius: 4px; cursor: help; }  /* a card's picture, a click on how it works: */
.mode-icon.act:hover { background: var(--border); color: var(--text); }  /* a grey square, as a row's × (see .row-act) */
/* Number tiles: the symbol only, several per row (name and formula in the tooltip) */
.number-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(48px, 1fr)); gap: 4px; margin-bottom: 10px; }
.number-grid button { padding: 6px 2px; font-size: 14px; white-space: nowrap; background: var(--panel); }
.number-grid button:hover { background: var(--bg); }
.number-grid sup { line-height: 0; }  /* an exponent (e^π√163) not raising its button */
.number-grid button.active { border-color: var(--accent); color: var(--accent); background: var(--pick); }
.mode-list button.active { border-color: var(--accent); background: var(--pick); }
.mode-list button.active .mode-name,
.mode-list button.active .mode-icon { color: var(--accent); }
.row button { white-space: nowrap; }
.row button:first-child { flex: 1; }

.progress {
  height: 4px;
  margin-top: 10px;
  background: var(--bg);
  border-radius: 2px;
  overflow: hidden;
}
#progressBar { height: 100%; width: 0; background: var(--accent); transition: width 0.1s; }
.muted { color: var(--muted); margin: 6px 0 0; font-size: 12px; }
.fill-note { color: var(--muted); font-size: 12px; margin-left: auto; }  /* under Area, when it cannot fill */


.activity { display: block; width: 100%; height: 36px; margin: 8px 0 4px; touch-action: none; }
.activity.seek { cursor: pointer; }  /* the activity curve (see drawActivity): a click or a drag goes to that step */
.activity.seek.out { cursor: not-allowed; }  /* (a Game of Life's, more than a second's play away: see lifeWithin) */
.strip {
  margin-top: 12px;
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 13px;
  word-break: break-all;
  color: var(--muted);
  min-height: 2.8em;
}
.strip.line { white-space: nowrap; overflow: hidden; }  /* digits: always one full line */
.strip:not(.line) { font-family: inherit; word-break: normal; }  /* texts (Life rule, marked cells): normal font, whole words */
.strip .cur { color: var(--accent-text); background: var(--accent); border-radius: 2px; }
.strip .dim { opacity: 0.5; }  /* the "0." of a number below 1: shown, not walked */
.strip.turns { position: relative; padding-left: 30px; }  /* the walker before the arrows and the digits */
.strip.turns > .icon { position: absolute; left: 0; top: 50%; width: 24px; height: 24px; transform: translateY(-50%); }
.strip .arrows { line-height: 1.1; }  /* each digit's step above it, one column each */
.strip .arrows span { display: inline-flex; justify-content: center; width: 1ch; }  /* a digit's width, centred on it */

.stage { position: relative; flex: 1; min-width: 0; overflow: hidden; cursor: grab; }
.stage.drawing { cursor: crosshair; }  /* Draw cells: a click colours a cell */
.draw-row { display: flex; align-items: center; gap: 6px; margin: 2px 0 10px; }  /* under Grid | Cells: the switch, and Clear while drawing */
.draw-row .check { flex: 1; margin: 0; }
.draw-row button { width: auto; padding: 4px 12px; }
.start-panel { margin: 0 0 10px; }
.start-panel > .field { margin-bottom: 10px; }  /* (Text's lines, then its fonts: the gap of every block) */
.light { display: inline-block; width: 12px; height: 12px; border-radius: 50%; vertical-align: middle; }  /* a hunt result's light: green, orange, red */
.colour-blocks button svg { border-radius: 3px; }  /* 1 to 12 colours: a block each, as the shapes' tiles */
.colour-blocks button:disabled { opacity: 0.3; }
.colour-swatches { display: flex; gap: 6px; justify-content: flex-start; align-items: center; padding-left: 4px; }  /* Life's colours: a square each, from the left */
/* the Rule section: cards with a pixel picture, then chips of neighbour counts */
.rule-icon rect, .rule-icon polygon { fill: currentColor; stroke: none; }
.rule-icon rect.dim, .rule-icon polygon.dim { opacity: 0.4; }
.rule-build { display: flex; flex-direction: column; gap: 4px; margin: 0 0 4px; }  /* your own's: one block under its card, as close as the cards */
.rule-build > .build-cols, .rule-build > .stepper { margin-bottom: 0; }
.rule-cards:has(+ .rule-build:not([hidden])) { margin-bottom: 4px; }  /* your own's block under them: all one (else a list's 10 px) */
.stack .field { margin-bottom: 4px; }  /* fields one under another, as close as cards (a battle's formulas, then Random) */
.build-cols { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; margin-bottom: 10px; }  /* Birth, Survive: a frame each */
.build-box { min-width: 0; padding: 6px 4px; border: 1px solid var(--border); border-radius: 8px; }
.build-box h4 { margin: 0 0 6px; font-size: 11px; font-weight: 600; color: var(--muted); text-align: center; }
#brushCards button:disabled { opacity: 0.55; }  /* a surface's patterns: to see, not to draw */
.nchips .r { display: flex; align-items: flex-start; gap: 2px; min-height: 24px; }  /* a count a row, its letters (if any) beside it */
.nchips .r > button { flex: none; }
.nchips .lt { display: flex; flex-wrap: wrap; gap: 2px; padding-top: 2.5px; }  /* the letters, wrapping: Hensel's are up to 13 */
.nchips button { width: 22px; height: 22px; padding: 0; border-radius: 50%; font-size: 11px; }
.nchips button.birth { background: #1d9e75; border-color: #1d9e75; color: #fff; }
.nchips button.survive { background: #378add; border-color: #378add; color: #fff; }
.nchips button.birth.partly { background: color-mix(in srgb, #1d9e75 35%, transparent); color: inherit; }  /* a count on for some of Callahan's letters only */
.nchips button.survive.partly { background: color-mix(in srgb, #378add 35%, transparent); color: inherit; }
.nchips .lt button { width: 17px; height: 17px; font-size: 10px; }  /* Callahan's or Hensel's letters, by their count */
.colour-swatches i { flex: 1 1 0; max-width: 34px; height: 34px; border-radius: 6px; }  /* as tall as the buttons beside */
.colour-swatches.off { opacity: 0.45; pointer-events: none; }  /* greyed, as a button disabled (Draw away from gen 0) */
#brushColours { flex: 1; }  /* Draw: the brush's colour, a square to click */
#brushColours i { cursor: pointer; }
#brushColours i.active { outline: 2px solid var(--accent); outline-offset: 2px; }  /* black or a colour, ringed alike */
.draw-row button.active { border-color: var(--accent); color: var(--accent); }
#brushColours i.eraser { display: flex; align-items: center; justify-content: center; background: var(--panel); border: 1px solid var(--border); color: var(--muted); }  /* a colour too: the dead one */
#brushColours i.eraser .icon { width: 18px; height: 18px; }
.turn-row button { flex: 1; }  /* the turns, always there (greyed for a cell); Open and Export PNG */
.colour-swatches span { font-size: 12px; color: var(--muted); font-weight: 400; }
#lifeStartTabs button { padding-left: 2px; padding-right: 2px; font-size: 11.5px; }  /* the starts on one row */
.stage.dragging { cursor: grabbing; }
.stage > canvas { position: absolute; inset: 0; width: 100%; height: 100%; }
.stage.faded > canvas:not(#hoverLayer) { opacity: 0.3; }  /* a size or the start hovered: all but its motif or its starts faded, fills and outlines alike */
/* The two boxes over the view (Play bottom left, Display top right): the same frame and
   translucency; hovering one opens the rest of it in the same frame (on touch screens, a tap) */
.stage-box {
  position: absolute;
  padding: 8px;
  background: var(--box);
  backdrop-filter: blur(4px);
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: default;
}
.stage-more { display: none; }
.stage-box:hover .stage-more { display: block; }
@media (hover: none) { .stage-box:focus-within .stage-more { display: block; } }
.display-menu { top: var(--view-gap); right: var(--view-gap); }
/* the number (Full number), in place of the whole view as how a rule works (.rule-tuto): its digits */
.number-view .number-digits { max-width: none; color: var(--text); font: 13px/1.5 ui-monospace, "SF Mono", Menlo, monospace; word-break: break-all; }
.number-view .number-digits + h3 { margin-top: 16px; }  /* (a battle's numbers: one, then the next's title) */
.number-view .number-digits.one-line { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; word-break: normal; }  /* (a battle's numbers: one line each) */
.tut-tools .icon { width: 16px; height: 16px; vertical-align: middle; }
button.wide.active, .head-btn.active { border-color: var(--accent); color: var(--accent); background: var(--pick); }
.display-menu:hover { width: 230px; }
@media (hover: none) { .display-menu:focus-within { width: 230px; } }
/* System stays at the top right; hovering opens the settings: the sky, Light and Dark on its left, tiles a quarter of the box, the rest below */
.display-menu .stage-head { display: flex; justify-content: flex-end; }
.head-tiles { display: flex; justify-content: flex-end; gap: 4px; margin-bottom: 0; }  /* closed: System alone, on the right */
.head-tiles button { width: calc((230px - 18px - 12px) / 4); }  /* (closed: as wide as a tile open, see .nav-shapes) */
.stage-box:hover .head-tiles { display: grid; flex: 1; }  /* open: the tiles' own grid (.nav-shapes), the box across, a tab group as wide as its tiles and their gaps */
.stage-box:hover .head-tiles button { width: auto; }
@media (hover: none) { .stage-box:focus-within .head-tiles { display: grid; flex: 1; } .stage-box:focus-within .head-tiles button { width: auto; } }
#themeButtons { margin-bottom: 0; }  /* (the sections below: their own line and margins, see .form-section) */
/* shown only while the box is open, like its other settings */
.stage-box .open-only { display: none; }
.stage-box:hover .open-only { display: flex; }
@media (hover: none) { .stage-box:focus-within .open-only { display: flex; } }
.display-menu .stage-more { margin: 10px 0 -10px; }  /* below the themes; each row's 10px under the last one taken back, so the bottom matches the top */
.form-section { margin-top: 10px; padding-top: 10px; border-top: 1px solid var(--border); }  /* shape and perspective */
.form-section:not(:has(> :not([hidden]))) { display: none; }
.choice-list { display: flex; flex-direction: column; gap: 4px; margin-bottom: 10px; }
.choice-list button { text-align: left; padding: 5px 8px; font-size: 13px; background: var(--panel); }
#torusTiles .icon { stroke-width: 1.3; transition: transform 0.2s; }  /* the torus's tilings, as the 2D grids (nav-shapes) */
/* Grid | Cells under the list: each side of the walk in use, its base and its digits */
/* the ant's rules to start from, written as they are typed */
.choice-list button.active { border-color: var(--accent); color: var(--accent); background: var(--pick); }
.stage-bar { left: var(--view-gap); bottom: var(--view-gap); width: calc(var(--player-width) + 2 * 12px + 2px); max-width: calc(100% - 2 * var(--view-gap)); padding: 12px; border-radius: 12px; outline: none; }  /* grows upwards: the Play row stays at the bottom (no focus ring: a tap opens it, see index.html) */
.stage-bar:hover { width: 680px; }
@media (hover: none) { .stage-bar:focus-within { width: 680px; } }
/* what is walked: the number, its loop and base; on hover the walk, its rule and the stats */
.ranking { position: relative; margin: 0 0 8px; font-size: 12px; }  /* a battle: a row a colour, re-sorted as it goes */
.ranking .rank-row { position: absolute; left: 0; right: 0; top: 0; height: 18px; display: grid; grid-template-columns: 16px 12px minmax(0, 1fr) 76px; align-items: center; gap: 6px; transition: transform 0.4s; }
.gauges:not([hidden]) { display: grid; grid-template-columns: minmax(64px, max-content) minmax(0, 112px) minmax(110px, max-content); grid-auto-rows: 18px; align-items: center; column-gap: 6px; }  /* one colour: fixed rows, one set of columns (a figure as wide as it needs, on one line) */
.gauges .gauge-row { display: contents; }
.gauges .rank-num { white-space: nowrap; }
.gauges .gauge-row > span:first-child { color: var(--muted); }
.ranking .rank-cell { display: none; white-space: nowrap; text-align: right; }
#ranking .rank-cell:nth-child(4) { display: block; }  /* folded: the table's alive column only */
.stage-bar:hover #ranking .rank-row { grid-template-columns: 16px 12px minmax(0, 1fr) var(--rank-columns); }
.stage-bar:hover #ranking .rank-cell { display: block; }  /* the player open: all of the table */
@media (hover: none) { .stage-bar:focus-within #ranking .rank-row { grid-template-columns: 16px 12px minmax(0, 1fr) var(--rank-columns); } .stage-bar:focus-within #ranking .rank-cell { display: block; } }  /* (touch: a tap opens it) */
.ranking .rank-row > span:first-child { color: var(--muted); text-align: right; }
.ranking .rank-row > i { width: 12px; height: 12px; border-radius: 3px; }
.ranking .rank-bar { height: 6px; border-radius: 3px; background: var(--border); overflow: hidden; }
.ranking .rank-bar i { display: block; height: 100%; border-radius: 3px; transition: width 0.4s; }
.ranking .rank-num { text-align: right; color: var(--muted); }
.ranking .rank-row.dead > i { opacity: 0.35; }
.ranking .all-dead { position: absolute; left: 0; top: 0; line-height: 18px; font-weight: 600; }
.bar-title { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 8px; margin-bottom: 8px; white-space: nowrap; overflow: hidden; }  /* the title, its chips on its right, on the next line when there is no room */
.bar-num { flex: 0 1 auto; min-width: 0; max-width: 100%; font-size: 20px; font-weight: 700; color: var(--accent); overflow: hidden; text-overflow: ellipsis; }  /* the number first */
.bar-sub { margin: -4px 0 8px; font-size: 12px; color: var(--muted); }
.bar-sub b { color: var(--text); }
.rule-chips { display: grid; grid-template-columns: repeat(auto-fit, minmax(80px, 1fr)); gap: 5px; margin-bottom: 9px; }
.rule-chips:empty { display: none; }
.bar-title.life .bar-num { font-size: 18px; white-space: pre; }  /* Life's title, a creature's, a battle's */
.bar-title .rank-titles { margin-left: auto; align-self: flex-end; display: grid; grid-template-columns: 76px; gap: 6px; font-size: 11px; color: var(--muted); text-align: right; }  /* over the ranking's columns, as wide */
.bar-title .rank-titles span:not(:first-child) { display: none; }  /* folded: its first */
.stage-bar:hover .bar-title .rank-titles { grid-template-columns: var(--rank-columns); }
.stage-bar:hover .bar-title .rank-titles span { display: block; }
@media (hover: none) { .stage-bar:focus-within .bar-title .rank-titles { grid-template-columns: var(--rank-columns); } .stage-bar:focus-within .bar-title .rank-titles span { display: block; } }
.rule-chip { display: flex; align-items: center; gap: 6px; padding: 4px 7px 4px 4px; border: 1px solid var(--border); border-radius: 9px; background: var(--bg); font-size: 12px; min-width: 0; }
.rule-chip b { flex: none; display: grid; place-items: center; width: 22px; height: 22px; border-radius: 50%; font-size: 11px; color: #0d1117; }
.rule-chip span { display: flex; flex-direction: column; line-height: 1.15; min-width: 0; white-space: nowrap; }
.rule-chip.next, .rule-chip.read { border: 2px solid color-mix(in srgb, var(--c) 75%, var(--text)); padding: 3px 6px 3px 3px; }  /* the next step's chip, step by step: its colour, a little toward the text so that a pale one shows */
.rule-chip.next { background: color-mix(in srgb, var(--c) 12%, var(--bg)); }
.rule-chip.read { border-style: dashed; }  /* an ant's digit read, turned the other way by a dark cell */
.rule-chip small { color: var(--muted); font-size: 11px; }
.stage-bar .stage-more { margin-bottom: 9px; }
.stage-bar .strip { margin: 8px 0 0; min-height: 0; font-size: 14px; }
.stage-bar .strip:empty { display: none; }
.stage-bar .row { margin: 0; align-items: center; }
.stage-bar .row button {  /* ⏮ ◀▮ ▮▶ ⏭: of one width and height, their icon centred; Play the rest (six buttons in every mode: as wide in all) */
  flex: none; width: 48px; height: 32px; padding: 0; font-weight: 600;
  display: inline-flex; align-items: center; justify-content: center;
}
/* Play keeps one width, so Play and Pause are alike: outlined in yellow, filled while playing */
.stage-bar #play { flex: 1; color: var(--accent); border-color: var(--accent); }
.stage-bar #reverse { color: var(--accent); border-color: var(--accent); }  /* as Play */
/* six buttons in every mode, the folded bar's width; open, on their right the speed, typed as the length (above the
   title, as wide as the buttons), the turtle and the rabbit */
.player-controls { display: flex; gap: 8px; align-items: flex-end; }  /* the buttons where they were, open or not */
.player-main { flex: none; width: var(--player-width); max-width: 100%; }  /* its six buttons, the folded bar's inner width: Play the rest (beside ◀ a button's, its icon only; Life's, two and their gap) */
.play-row:has(#reverse:not([hidden])) .play-words { display: none; }
.player-side { flex: none; width: 250px; margin-left: auto; display: flex; flex-direction: column; justify-content: space-between; align-self: stretch; }
.length-row { display: flex; align-items: flex-start; gap: 8px; }  /* open, under the curve: the digits being computed (their gauge) */
.length-row #digitsRow { flex: none; width: var(--player-width); max-width: 100%; }  /* (as wide as the folded bar's buttons) */
.stage-bar:not(:hover) .player-side { display: none; }
@media (hover: none) { .stage-bar:focus-within .player-side { display: flex; } }
.stage-bar .stepper { margin: 0 0 8px; }
.stage-bar .progress { margin: 0 0 8px; }
#digitsRow:not(.busy) .progress, #digitsRow.busy .stepper { display: none; }
#digitsRow.busy .progress { position: relative; height: 34px; border: 1px solid var(--border); border-radius: 6px; }
#progress.indeterminate #progressBar { width: 30% !important; animation: gauge-slide 1.2s ease-in-out infinite alternate; }  /* drawn apart: it slides on while the walk is built */
@keyframes gauge-slide { from { transform: translateX(0); } to { transform: translateX(233%); } }
#progressText { position: absolute; inset: 0; display: grid; place-items: center; font-size: 12px; color: var(--text); }
#status:not(:empty)::before { content: ' · '; }  /* after the description */
.stage-bar .speed-stepper { margin: 0; }
.speed-stepper button { width: 48px; }
.speed-stepper input, .speed-stepper button { height: 32px; }  /* as high as the buttons beside */
.speed-stepper input { color: var(--text); font-weight: 400; }
/* the steps, on their own line above the buttons; the speed after ⏭, between a turtle and a rabbit */
.speed-icon { flex: none; width: 23px; height: 23px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }

.step-line { font-size: 20px; font-weight: 700; color: var(--text); white-space: nowrap; margin-bottom: 4px; }  /* the step or generation shown, as large as the title, folded or open, every mode */
.digits-pad { visibility: hidden; }  /* a count's hidden zeros in front: as wide as its widest (see fmtAsWide) */
.step-line #stepLast { color: var(--muted); }  /* its last, after it, always: the line keeps its width */
.step-line .end-words { display: none; }  /* its end's words, open only (folded: its mark) */
.stage-bar:hover .step-line .end-words { display: inline; }
@media (hover: none) { .stage-bar:focus-within .step-line .end-words { display: inline; } }
.step-line #stepEnd:not(:empty), .step-line .bubble { margin-left: 10px; }  /* its end (a loop, a death), shown folded too; a reversible one's bound */
.step-line .bubble { vertical-align: 3px; }
.stage-bar #play.on, .stage-bar #reverse.on { background: var(--accent); color: var(--accent-text); }
.hint {
  position: absolute;
  right: var(--view-gap);
  bottom: var(--view-gap);
  font-size: 12px;
  line-height: 1.5;
  white-space: pre-line;  /* its lines stacked in the bottom right corner, each a box (below) */
  pointer-events: none;
  z-index: 3;  /* (over the view's boxes: the player's, the display's) */
}
/* a tooltip, the view's hint: each in a box as the view's others (see .stage-box), its lines left aligned, the name on its own */
#tip:not(:empty), #hint:not([hidden]) { max-width: 420px; margin-left: auto; padding: 6px 10px; background: var(--box); backdrop-filter: blur(4px); border: 1px solid var(--border); border-radius: 8px; color: var(--text); text-align: left; }
#tip:empty { display: none; }
#hint:not([hidden]) { width: max-content; }
.tip-name { display: block; }  /* (a control's name, a line of its own) */
.tip-default { color: var(--muted); }  /* a control's default, under its tooltip: fainter */
.tip-y { color: var(--motif); } .tip-r { color: var(--face); } .tip-s { color: var(--sector); } .tip-k { color: var(--cell); } .tip-o { color: #c4934e; }  /* a size's words in the colours drawn (see sizeTips; the walls': LIFE_WALL) */

@media (max-width: 720px) {
  main { flex-direction: column; }
  .panel { width: auto; max-height: 45vh; border-right: 0; border-bottom: 1px solid var(--border); }
  .stage { min-height: 55vh; }
  .hint { display: none; }
  /* folded, the player alone: ⏮, a step back and Play (a tap opens it all), the grid in sight */
  .stage-bar:not(:focus-within) > :not(.player-controls),
  .stage-bar:not(:focus-within) #step, .stage-bar:not(:focus-within) #end, .stage-bar:not(:focus-within) #jump10k { display: none; }
  .stage-bar:not(:focus-within) { width: auto; }
}

/* Save, the first of the Gallery's icons: yellow, its star filled, while the setup in view is one of them */
.pane-tab .fav { border: 1px solid transparent; border-radius: 7px; padding: 3px; margin: -4px; }  /* (its frame round it as an icon button's, its tab's size the same) */
.pane-tab .fav.saved { color: var(--accent); }  /* Gallery's ☆: as its tab's colour, ★ gold while the setup in view is in the Gallery */
.fav.saved .icon path { fill: currentColor; }
.icon-btn .icon { width: 16px; height: 16px; }
/* The Gallery: Export and Import as two small icons at the right of its heading */
.icon-btn { display: grid; place-items: center; width: 28px; height: 28px; padding: 0; border-radius: 7px; background: transparent; border-color: transparent; color: var(--muted); }
.icon-btn:hover:not(:disabled), .pane-tab .fav:hover { color: var(--accent); border-color: var(--border); background: var(--bg); }  /* (Gallery's ☆ too: a button in its tab) */
.icon-btn svg { width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
/* Gallery, the first tab at the top: a click opens the gallery in the left pane, lit as the tab in use (the walk's tab not, till
   it is closed) */
.tabs button.pane-tab.open { color: var(--accent); border-bottom-color: var(--accent); }  /* a pane's tab (Gallery, the app's) lit while it shows */
.tabs:has(.pane-tab.open) button.active:not(.pane-tab) { color: var(--muted); border-bottom-color: transparent; }
.caption { margin: 3px 0 0; font-size: 11px; color: var(--muted); }  /* a line under a heading: where the Gallery is kept */
#barBase { flex: none; }  /* the base whole: only the loop chip shortens */

/* how a rule works (ruleTutorial): over the grid, its cells as the grid's, a pair each count (before → after) */
.rule-tuto { position: absolute; inset: 0; z-index: 5; overflow: hidden; cursor: auto; background: var(--bg); color: var(--text); }
.tut-body { position: absolute; inset: 0; overflow: auto; padding: 20px 24px 24px; }  /* what scrolls, under its buttons (pinned to the top right) */
.tut-body > h3, .tut-body > h3 + p:not(.number-digits) { margin-right: 96px; }  /* (beside the buttons) */
.tut-body code { color: var(--text); font-weight: 700; text-transform: none; letter-spacing: 0; }  /* the rule itself, wherever: black and bold (the labels grey) */
.tut-body > h3 code { overflow-wrap: anywhere; }  /* (a long rule: on as many lines; a block rule's numbers, after its commas, see blockTutorial) */
.rule-tuto h3 { margin: 0 96px 6px 0; font-size: 18px; }  /* (beside the buttons) */ .rule-tuto h3 code { margin-left: 6px; }  /* (as big as its name) */
.rule-tuto h4 { margin: 18px 0 6px; font-size: 13px; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); } .rule-tuto h4 code { margin-left: 8px; font-size: 13px; }
.rule-tuto p { margin: 0; font-size: 13px; color: var(--muted); max-width: 640px; }
.tut-row { display: flex; flex-wrap: wrap; gap: 10px; }
.tut-row figure { margin: 0; padding: 6px 8px; border: 1px solid var(--border); border-radius: 10px; background: var(--panel); }  /* as wide as its cells: they never wrap, its words never widen it */
.tut-row figure > div { display: flex; flex-wrap: nowrap; align-items: center; gap: 4px; }
.tut-row figure > div > span { color: var(--muted); }
.tut-row figure svg { flex: none; width: 88px; height: 88px; }
.tut-row figure svg.tut-start { width: 176px; height: 176px; }  /* a loop's start: twice as large (see loopTutorial) */
.tut-row figcaption { width: 0; min-width: 100%; margin-top: 4px; font-size: 11px; color: var(--muted); text-align: center; }
.tut-shapes { margin-bottom: 10px; }  /* a tiling's shapes: a bubble each, a click shows it; two of them as wide as a rule's bubble
   (two pictures of 88 px, the arrow between: 214 px) with the row's gap between them, as high */
.tut-shapes figure { cursor: pointer; width: 102px; height: 121px; padding: 6px; display: flex; flex-direction: column; justify-content: center; }  /* as the shapes' buttons: a dark frame on hover, gold picked */
.tut-shapes figure:hover { border-color: var(--muted); }
.tut-shapes figure.active { border-color: var(--accent); color: var(--accent); background: var(--pick); }
.tut-shapes figure.active figcaption { color: var(--accent); }
.tut-shapes figure > div { justify-content: center; }
.tut-shapes figure svg { width: 82px; height: 82px; }
.tut-shapes figcaption { width: auto; margin-top: 4px; }  /* (its name as wide as it is) */
.tut-phases figure svg { width: 132px; height: 132px; }  /* (a piece of the grid: its blocks, bigger) */
.tut-walk figure svg { width: 96px; height: 96px; stroke-linecap: round; }  /* a walk's step: the way in, the step, the other digits' */
.tut-walk .tut-way { stroke: var(--border); stroke-width: 0.05; }
.tut-walk .tut-in { stroke: var(--muted); stroke-width: 0.09; }
.tut-walk .tut-step { stroke: var(--accent); stroke-width: 0.12; }
.tut-walk .tut-end { fill: var(--border); }
.tut-walk .tut-here { fill: var(--muted); }
.tut-walk .tut-to { fill: var(--accent); r: 0.14; }
.tut-walk .tut-step, .tut-walk .tut-to, .tut-walk .tut-next, .tut-walk .tut-cell-to { animation: tut-appear 0.8s ease-out both; }  /* the step lit softly, as a cell's colour fades */
.highlit { animation: highlight 0.8s ease-out; }  /* highlighted a moment (see highlight): the length asked's stepper, the buttons a greyed one waits for */
.max-steps.highlit { border-radius: 8px; }
@keyframes highlight { from { box-shadow: 0 0 0 0 var(--accent); } to { box-shadow: 0 0 0 10px transparent; } }
@keyframes tut-appear { 0%, 30% { opacity: 0; } 100% { opacity: 1; } }
.tut-walk .tut-next { stroke: var(--accent); stroke-width: 0.07; stroke-dasharray: 0.12 0.12; }
.tut-walk .tut-dashed { stroke-dasharray: 0.18 0.16; }
.tut-walk .tut-cell { fill: none; stroke: var(--border); stroke-width: 0.03; }
.tut-battle figure svg { width: 132px; height: 132px; }  /* (a battle's case: a piece of its grid, bigger) */
.tut-walk .tut-cell-here { fill: var(--border); stroke: var(--border); stroke-width: 0.03; }
.tut-walk .tut-cell-to { fill: color-mix(in srgb, var(--accent) 25%, transparent); stroke: var(--accent); stroke-width: 0.04; }
.tut-row .tut-centre { stroke: var(--accent); stroke-linejoin: round; }
.tut-tools { position: absolute; top: 12px; right: 24px; z-index: 1; display: flex; gap: 6px; }  /* (as high as Display's box; on the right, room for the scroll bar) */
.tut-tools button { width: 36px; height: 36px; padding: 0; display: inline-flex; align-items: center; justify-content: center; font-size: 15px; line-height: 1; }  /* one size, whatever they hold */
.tut-tools button.tut-word { width: auto; padding: 0 12px; font-size: 13px; }  /* a word (Letters, a switch; Share, Home) */
.tut-tools button.tut-word.active { border-color: var(--accent); color: var(--accent); }
.tut-note { margin: -4px 0 10px; font-size: 12px; color: var(--muted); }  /* one shape in several bubbles, said */
#colourBlocks button, .nav-shapes button { position: relative; }
button.mark::after { content: ''; position: absolute; right: 0; bottom: 0; width: 9px; height: 9px; border-bottom-right-radius: 5px; background: linear-gradient(135deg, transparent 50%, var(--border) 50%); }  /* a count of colours whose battles can bring a colour back (the rule's ties): a triangle in its corner, its tip the button's round, in its border's colour */
button.mark:hover:not(:disabled)::after { background: linear-gradient(135deg, transparent 50%, var(--muted) 50%); }
button.mark.active::after { background: linear-gradient(135deg, transparent 50%, var(--accent) 50%); }

.gen-link { color: inherit; text-decoration: none; cursor: pointer; }  /* a generation of the run in view: clicked, it goes there (see genLink) */
.gen-link:hover { text-decoration: underline; }
.gen-loop { color: var(--cell); }  /* a loop's first generation, as its mark on the curve */