/* entry.css — presentation of a single color group G/H[n].
 *
 * Layout is fluid: the panels and the coset table reflow to the window instead
 * of living inside a fixed column.  The artwork is unchanged — square PNGs
 * stacked as absolutely-positioned layers.
 *
 * Every .stack is click-to-enlarge; the table cell size is driven by --cell so
 * that a table with many colors can shrink without the page having to change. */

:root {
  --bg:      #f4f4f4;
  --panel:   #ffffff;
  --ink:     #1a1a1a;
  --muted:   #6a6a6a;
  --line:    #cfcfcf;
  --rule:    #e2e2e2;
  --accent:  #0b5fa5;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  /* the three color classes, sampled from the artwork */
  --c0: #00ffff;
  --c1: #ffff00;
  --c2: #ff0000;
  --cell: 235px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  padding: 0 0 3rem;
  background: var(--bg);
  color: var(--ink);
  font: 15px/1.55 system-ui, -apple-system, "Segoe UI", Arial, sans-serif;
}

.wrap { max-width: 1500px; margin: 0 auto; padding: 0 1.25rem; }

/* ---- header ------------------------------------------------------------ */

header.entry {
  background: #e8e8e8;
  border-bottom: 1px solid var(--line);
  padding: 1rem 0 .9rem;
  margin-bottom: 1.5rem;
}
header.entry h1 { margin: 0; font-size: 1.75rem; font-weight: 600; letter-spacing: .01em; }
header.entry h1 .sub { color: var(--muted); font-weight: 400; }
header.entry .lede { margin: .2rem 0 0; color: var(--muted); font-size: .9rem; }

/* ---- section headings -------------------------------------------------- */

h2.sec {
  font-size: .8rem; font-weight: 600; text-transform: uppercase;
  letter-spacing: .09em; color: var(--muted);
  margin: 2.2rem 0 .8rem; padding-bottom: .35rem;
  border-bottom: 1px solid var(--line);
}

/* ---- facts ------------------------------------------------------------- */

.facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1px; background: var(--rule); border: 1px solid var(--line);
  margin: 0;
}
.fact { background: var(--panel); padding: .75rem .9rem; }
.fact dt {
  font-size: .72rem; text-transform: uppercase; letter-spacing: .07em;
  color: var(--muted); margin-bottom: .3rem;
}
.fact dd { margin: 0; font-size: 1.02rem; }
.fact dd .note { display: block; font-size: .82rem; color: var(--muted); margin-top: .2rem; }
code, .mono { font-family: var(--mono); font-size: .92em; }
.name { font-family: var(--mono); font-weight: 600; color: var(--ink); }

/* ---- the colour action table ------------------------------------------- */

table.action { border-collapse: collapse; background: var(--panel); }
table.action th, table.action td {
  border: 1px solid var(--rule); padding: .3rem .55rem; text-align: center;
}
table.action th { font-weight: 600; color: var(--muted); font-size: .8rem; }
table.action th.gen { font-family: var(--mono); color: var(--ink); font-size: .95rem; }
table.action td.cyc { text-align: left; font-family: var(--mono); color: var(--muted); }

.sw {
  display: inline-block; width: 1.15em; height: 1.15em;
  border: 1px solid #999; vertical-align: -.22em; border-radius: 2px;
}
.sw0 { background: var(--c0); }
.sw1 { background: var(--c1); }
.sw2 { background: var(--c2); }

/* ---- image stacks ------------------------------------------------------ */

.stack {
  position: relative;
  aspect-ratio: 1 / 1;
  background: var(--panel);
  border: 1px solid var(--line);
  overflow: hidden;
  cursor: zoom-in;
}
.stack:hover, .stack:focus-visible { border-color: var(--accent); outline: none; }
.stack:focus-visible { box-shadow: 0 0 0 2px var(--accent); }
.stack img { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }
.stack .cap {
  position: absolute; top: 0; left: 0; z-index: 2;
  background: rgba(255,255,255,.86); padding: .1rem .4rem; font-size: .8rem;
  border-right: 1px solid var(--rule); border-bottom: 1px solid var(--rule);
}
.op20 { opacity: .2; }
.op30 { opacity: .3; }
.op50 { opacity: .5; }

/* Exact channel permutations for recoloring the pure-cyan motif layers
 * (filter defs live in the entry page).  Greys pass through untouched. */
.toY { filter: url(#toY); }   /* cyan -> yellow */
.toR { filter: url(#toR); }   /* cyan -> red    */

/* ---- panel rows -------------------------------------------------------- */

/* auto-fill, not auto-fit: a short row keeps its track width instead of
 * stretching, so the rows line up with each other. */
.hero-one, .hero-row, .geometry {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.1rem;
}
.hero-one { margin-bottom: 1.3rem; }
.geometry { grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: .9rem; }
.hero-one figure, .hero-row figure, .geometry figure { margin: 0; }
.hero-one figcaption, .hero-row figcaption, .geometry figcaption {
  font-size: .87rem; color: var(--muted); margin-top: .4rem;
}
.hero-one figcaption b, .hero-row figcaption b, .geometry figcaption b {
  color: var(--ink); font-weight: 600;
}

/* ---- the coset table --------------------------------------------------- */

.cosets { overflow-x: auto; }
table.grid { border-collapse: collapse; }
table.grid th, table.grid td { padding: 0; vertical-align: top; }
table.grid td.cell { padding: 3px; }
table.grid td.cell .stack { width: var(--cell); }
table.grid th.col {
  font-size: .85rem; font-weight: 600; padding: 0 0 .35rem;
  text-align: center; color: var(--ink);
}
table.grid th.row {
  font-size: .85rem; font-weight: 600; padding-right: .55rem;
  text-align: right; white-space: nowrap; color: var(--ink);
}
table.grid th .hint { display: block; font-weight: 400; font-size: .76rem; color: var(--muted); }
table.grid .marg { background: #ececec; }

.legend { font-size: .87rem; color: var(--muted); margin: .8rem 0 0; max-width: 95ch; }
.legend b { color: var(--ink); }

/* ---- lightbox ---------------------------------------------------------- */

#lb {
  position: fixed; inset: 0; z-index: 50;
  background: rgba(20,20,20,.62);
  display: grid; place-items: center; padding: 1.5rem;
  cursor: zoom-out;
}
#lb[hidden] { display: none; }
#lb-stack {
  width: min(86vw, 78vh);
  border-color: var(--muted);
  cursor: zoom-out;
  box-shadow: 0 8px 40px rgba(0,0,0,.45);
}
#lb-stack .cap { font-size: 1rem; padding: .2rem .55rem; }
#lb-hint {
  margin-top: .6rem; text-align: center; color: #f0f0f0;
  font-size: .82rem; text-shadow: 0 1px 3px rgba(0,0,0,.6);
}

/* ---- footer ------------------------------------------------------------ */

footer.entry {
  border-top: 1px solid var(--line);
  margin-top: 2.5rem; padding-top: .9rem;
  font-size: .87rem; color: var(--muted);
}
footer.entry a { color: var(--accent); }

/* longer prose inside a .fact box (the f / g definitions) */
.fact dd.small { font-size: .87rem; line-height: 1.5; color: var(--ink); }
/* keep case-sensitive math symbols as written: lowercase f, g are not G */
.fact dt.plain { text-transform: none; letter-spacing: .01em; font-size: .82rem; }