/* Two-Color Patterns — page styles, after the "Catalog of colorings" page of
   yaroslavvb.github.io/animated-groups (light, big serif family headings,
   teal accent, plate + details panes). */

:root {
  --pattern-ink: #171b19;
  --pattern-muted: #5d6864;
  --pattern-rule: #d4ded9;
  --pattern-soft: #f5f8f6;
  --pattern-accent: #00766b;
  --pattern-blue: #0072b2;
  --pattern-orange: #e69f00;
  --pattern-wine: #7d2140;
  --pattern-seat: #c8452c;
}

body.tcp {
  background: #fff;
  color: var(--pattern-ink);
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.55;
}
body.tcp header.site { background: #fff; }
body.tcp a { color: inherit; text-decoration-color: #b8c8c2; text-underline-offset: 0.2em; }
body.tcp a:hover { text-decoration-color: var(--pattern-accent); color: var(--pattern-accent); }

main.tcp-page {
  width: min(100% - 2rem, 1560px);
  max-width: none;
  margin: 0 auto;
  padding: clamp(1.8rem, 3.5vw, 3.6rem) 0 8rem;
}

/* ---------------------------------------------------------- directory */
.catalog-directory { margin-bottom: 2.5rem; }
.catalog-directory h1 {
  max-width: 1050px;
  margin: 0;
  font-size: clamp(2.75rem, 6vw, 5.4rem);
  font-weight: 670;
  letter-spacing: -0.075em;
  line-height: 0.92;
  border: 0;
}
.catalog-subtitle {
  display: flex; flex-wrap: wrap; gap: 0.35rem 1rem;
  margin: 0.9rem 0 1.4rem;
  color: #44504c; font-size: clamp(0.92rem, 1.3vw, 1.08rem); line-height: 1.4;
}
.catalog-subtitle strong { color: var(--pattern-accent); font-weight: 720; }
.directory-grid {
  display: grid; grid-template-columns: repeat(8, minmax(0, 1fr));
  gap: 0.5rem 0.6rem; width: min(100%, 68rem); margin: 1.25rem auto 0;
}
.directory-family {
  display: flex; flex-direction: column; align-items: center; min-width: 0; gap: 0.15rem;
  padding: 0.25rem; border-radius: 0.3rem; color: inherit; background: #fff; text-decoration: none;
  position: relative;
}
.directory-family:hover, .directory-family:focus-visible { background: #eef7f3; color: inherit; }
.directory-family strong {
  display: block; padding: 0 0.1rem 0.15rem; text-align: center;
  font: 700 clamp(0.95rem, 1.35vw, 1.2rem)/1 Georgia, "Times New Roman", serif;
}
.directory-family svg { display: block; width: 100%; height: auto; aspect-ratio: 4 / 3; border: 1px solid #cdd8d3; background: #f8f7f1; }
.directory-family .directory-count {
  position: absolute; right: 0.45rem; top: 1.55rem; font: 650 0.68rem/1 Arial, Helvetica, sans-serif;
  color: #fff; background: var(--pattern-accent); border-radius: 999px; padding: 0.15rem 0.4rem;
}
.directory-credit { max-width: 68rem; margin: 0.5rem auto 0; color: var(--pattern-muted); font-size: 0.74rem; line-height: 1.4; }

/* ---------------------------------------------------------- introduction */
.tcp-intro { max-width: 60rem; margin: 0 auto 4rem; }
.tcp-intro h2 { font: 700 1.55rem/1.2 Georgia, "Times New Roman", serif; margin: 2.4rem 0 0.7rem; padding: 0; border: 0; letter-spacing: -0.01em; }
.tcp-intro h3 { font: 700 1.12rem/1.3 Georgia, "Times New Roman", serif; margin: 1.6rem 0 0.4rem; }
.tcp-intro p, .tcp-intro li { font-size: 1.02rem; line-height: 1.6; color: #232926; }
.tcp-intro .lead { font-size: 1.15rem; color: #37413d; max-width: 52rem; }
.tcp-intro .thm {
  margin: 1.2rem 0; padding: 0.9rem 1.1rem; border-left: 4px solid var(--pattern-accent);
  background: var(--pattern-soft); border-radius: 0 0.5rem 0.5rem 0;
}
.tcp-intro .thm .label { display: block; font: 700 0.74rem/1.3 Arial, Helvetica, sans-serif; letter-spacing: 0.08em; text-transform: uppercase; color: var(--pattern-accent); margin-bottom: 0.3rem; }
.tcp-intro .aside { border-left-color: var(--pattern-orange); }
.tcp-intro .aside .label { color: #a26f00; }
.tcp-intro table.recipe { width: 100%; border-collapse: collapse; font-size: 0.92rem; margin: 1rem 0 1.4rem; }
.tcp-intro table.recipe th, .tcp-intro table.recipe td { padding: 0.5rem 0.6rem; border-bottom: 1px solid var(--pattern-rule); text-align: left; vertical-align: top; }
.tcp-intro table.recipe th { color: var(--pattern-muted); font-weight: 650; background: var(--pattern-soft); }
.tcp-intro table.recipe tr.this td { background: #eef7f3; }
.tcp-intro .sym, .sym { font-family: "STIX Two Math", "Cambria Math", Georgia, "Times New Roman", serif; }
.intro-figure { display: grid; grid-template-columns: 1fr 1fr; gap: 1.2rem; margin: 1.4rem 0; }
.intro-plate { margin: 0; }
.intro-plate svg { display: block; width: 100%; height: auto; aspect-ratio: 12 / 7; border: 1px solid #cdd8d3; background: #f8f7f1; }
.intro-plate figcaption { font-size: 0.86rem; color: var(--pattern-muted); margin-top: 0.4rem; }
.tcp-intro figure.gsfig { margin: 1.4rem 0; text-align: center; }
.tcp-intro figure.gsfig img { max-width: 100%; border: 1px solid var(--pattern-rule); border-radius: 8px; }
.tcp-intro figure.gsfig figcaption { font-size: 0.86rem; color: var(--pattern-muted); margin-top: 0.4rem; text-align: left; }
.tcp-intro code, .tcp-intro .mono { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 0.9em; }
.tcp-intro ul { padding-left: 1.3rem; }
.tcp-intro .refs { font-size: 0.9rem; color: #37413d; }

/* signature typography */
.sig { font: 650 1.02rem/1.15 Georgia, "Times New Roman", serif; white-space: nowrap; }
.sig-big { font-size: 1.22rem; }
.sig sup { font-size: 0.6em; line-height: 0; vertical-align: 0.66em; }
.sig .sig-sym { font-family: "STIX Two Math", "Cambria Math", "Times New Roman", serif; }
.sig .seat-mark, .sig-annot .seat-mark {
  color: var(--pattern-seat);
  background: #fde8e2;
  border-radius: 0.2em;
  padding: 0 0.08em;
  box-shadow: 0 0 0 1px #f2c3b7;
}
.sig-annot .gen-letter { font-style: italic; color: var(--pattern-accent); font-weight: 700; font-size: 0.62em; line-height: 0; vertical-align: 0.66em; }
.seat-text { color: var(--pattern-seat); font-weight: 650; font-size: 0.92rem; }

/* ---------------------------------------------------------- atlas */
.pattern-atlas { display: grid; gap: 5rem; }
.wallpaper-family { min-width: 0; scroll-margin-top: 4.5rem; }
.family-header {
  display: grid; grid-template-columns: minmax(11rem, 0.32fr) minmax(0, 1fr);
  align-items: baseline; gap: 2rem; padding: 0 0 1.2rem; border-bottom: 1px solid var(--pattern-rule);
}
.family-header h2 { display: flex; align-items: baseline; gap: 0.75rem; margin: 0; border: 0; padding: 0; }
.family-orbifold { font: 700 clamp(2.6rem, 5vw, 5rem)/0.9 Georgia, "Times New Roman", serif; letter-spacing: -0.055em; }
.family-hm { color: var(--pattern-muted); font-size: 0.92rem; font-weight: 650; }
.family-header p { margin: 0; color: #3f4a46; font-size: 1.02rem; }

.colour-group-tabs { display: flex; flex-wrap: wrap; gap: 0.55rem; padding: 1rem 0 0; }
.colour-group-tab {
  display: grid; flex: 0 0 auto; min-width: 9.5rem; padding: 0.6rem 0.8rem 0.55rem;
  border: 1px solid var(--pattern-rule); border-bottom-color: #aebbb5; border-radius: 0.65rem;
  color: #4d5955; background: var(--pattern-soft); text-decoration: none;
}
.colour-group-tab:hover, .colour-group-tab:focus-visible { border-color: #83978e; color: var(--pattern-ink); background: #fff; outline: none; }
.tab-name { min-height: 1.5rem; }
.tab-palette { display: flex; width: 100%; height: 0.42rem; margin: 0.45rem 0 0.3rem; overflow: hidden; border: 1px solid #aab5b0; border-radius: 999px; }
.tab-palette span { flex: 1 1 0; background: var(--swatch); }
.tab-sub { font-size: 0.72rem; color: var(--pattern-muted); }

.colour-group-band { margin-top: 1.4rem; border: 1px solid var(--pattern-rule); border-radius: 0.6rem; background: #fff; scroll-margin-top: 4.5rem; }
.band-header { padding: 0.9rem clamp(1rem, 2vw, 1.6rem) 0.7rem; border-bottom: 1px solid var(--pattern-rule); background: var(--pattern-soft); border-radius: 0.6rem 0.6rem 0 0; }
.band-header h3 { margin: 0; font: 700 1.3rem/1.2 Georgia, "Times New Roman", serif; display: flex; gap: 0.9rem; align-items: baseline; flex-wrap: wrap; }
.band-type { font-family: "STIX Two Math", "Cambria Math", Georgia, serif; }
.band-meta { margin: 0.25rem 0 0; font-size: 0.86rem; color: #3f4a46; }

.pattern-pane { border-top: 1px solid var(--pattern-rule); scroll-margin-top: 4.5rem; }
.pattern-pane:first-of-type { border-top: 0; }
.pane-head { display: flex; align-items: baseline; justify-content: space-between; padding: 0.7rem clamp(1rem, 2vw, 1.6rem) 0; }
.pane-title { margin: 0; font: 700 1.05rem/1.2 Georgia, "Times New Roman", serif; }
.pane-gs { color: var(--pattern-ink); }
.pane-sub { color: var(--pattern-muted); font-weight: 500; font-size: 0.9rem; }
.pane-permalink { color: #9aa8a2; text-decoration: none; font-size: 0.9rem; }
.pane-body {
  display: grid; grid-template-columns: minmax(0, 1.22fr) minmax(22rem, 0.78fr);
  gap: clamp(1rem, 2vw, 2rem); padding: 0.5rem clamp(1rem, 2vw, 1.6rem) clamp(1rem, 2vw, 1.6rem);
}
.pattern-plate { margin: 0; min-width: 0; }
.pattern-plate svg { display: block; width: 100%; height: auto; aspect-ratio: 12 / 7; border: 1px solid #cdd8d3; background: #f8f7f1; }
.pattern-plate figcaption { font-size: 0.74rem; color: var(--pattern-muted); margin-top: 0.35rem; }
.cap-keep { color: var(--pattern-wine); font-weight: 650; }
.cap-swap { color: var(--pattern-wine); font-weight: 650; }
.pattern-details { min-width: 0; align-self: start; }

.plate-bg { fill: #f8f7f1; }
.motif-fill { stroke: #26322e; stroke-width: 1.2px; vector-effect: non-scaling-stroke; }
.motif-letter { fill: #fffaf1; stroke: #26322e; stroke-width: 0.6; paint-order: stroke fill; font-family: Arial, Helvetica, sans-serif; font-weight: 800; }
.generator-overlay { pointer-events: none; }
.gen-halo { fill: none; stroke: rgba(255, 253, 247, 0.9); stroke-width: 6px; stroke-linecap: round; vector-effect: non-scaling-stroke; }
.gen-mirror { fill: none; stroke: var(--pattern-wine); stroke-width: 2.1px; vector-effect: non-scaling-stroke; }
.gen-glide { fill: none; stroke: var(--pattern-wine); stroke-width: 1.8px; vector-effect: non-scaling-stroke; }
.gen.swaps .gen-mirror { stroke-dasharray: 11 8; }
.gen.swaps .gen-glide { stroke-dasharray: 8 6; }
.gen-glide-vec { stroke: var(--pattern-wine); stroke-width: 2.6px; vector-effect: non-scaling-stroke; }
.gen-arc { fill: none; stroke: var(--pattern-wine); stroke-width: 2.1px; stroke-linecap: round; vector-effect: non-scaling-stroke; }
.gen.swaps .gen-arc { stroke-dasharray: 5 4; }
.gen-arrow { fill: var(--pattern-wine); stroke: rgba(255, 253, 247, 0.9); stroke-width: 1.2px; paint-order: stroke fill; }
.gen-centre { fill: var(--pattern-wine); stroke: #fffdf7; stroke-width: 2.3px; }
.gen.swaps .gen-centre { fill: #fff; stroke: var(--pattern-wine); stroke-width: 2.4px; }
.gen-label { fill: #5f1731; stroke: rgba(255, 253, 247, 0.96); stroke-width: 5px; paint-order: stroke fill; font-family: "STIX Two Math", "Cambria Math", Georgia, serif; font-size: 22px; font-weight: 800; }
.seat-ring { fill: none; stroke: var(--pattern-seat); stroke-width: 2.4px; stroke-dasharray: 4 3; }

.pattern-data { width: 100%; border-collapse: collapse; font-size: clamp(0.84rem, 1vw, 0.95rem); }
.pattern-data th, .pattern-data td { padding: 0.6rem 0.6rem; border-bottom: 1px solid var(--pattern-rule); text-align: left; vertical-align: top; }
.pattern-data th { width: 34%; color: var(--pattern-muted); font-weight: 650; }
.pattern-data tr:last-child th, .pattern-data tr:last-child td { border-bottom: 0; }
.source-value-link { display: inline-flex; align-items: baseline; gap: 0.32rem; color: var(--pattern-ink); font: 650 1.05rem/1.15 Georgia, "Times New Roman", serif; text-decoration-color: #7f9c92; }
.source-value-link:hover, .source-value-link:focus-visible { color: var(--pattern-accent); }
.source-math-symbol { font: 650 1.05rem/1.15 Georgia, "Times New Roman", serif; }
.source-link-mark { color: var(--pattern-accent); font: 650 0.72rem/1 Arial, Helvetica, sans-serif; }
.ghk-expression { display: inline-flex; align-items: baseline; gap: 0.28rem; white-space: nowrap; }
.ghk-term { cursor: help; }
.ghk-separator { color: #809089; font-weight: 400; }
.ghk-legend { display: block; margin-top: 0.3rem; font: 400 0.76rem/1.45 Arial, Helvetica, sans-serif; color: var(--pattern-muted); white-space: normal; }
.pane-ghk { font: 650 0.95rem/1.2 Georgia, "Times New Roman", serif; color: var(--pattern-ink); }
.pane-ghk .ghk-separator { color: #9aa8a2; }

.group-presentation { margin: 1.1rem 0 0; }
.presentation-heading { display: flex; align-items: center; justify-content: space-between; gap: 0.75rem; margin: 0 0 0.28rem; }
.group-presentation h4 { margin: 0; color: var(--pattern-ink); font-size: 0.82rem; font-weight: 700; }
.action-palette { display: flex; align-items: center; gap: 0.3rem; color: var(--pattern-muted); font: 650 0.72rem/1 Arial, Helvetica, sans-serif; white-space: nowrap; }
.action-colour { display: inline-grid; width: 1.45rem; height: 1.45rem; place-items: center; border: 1px solid #53625c; border-radius: 0.2rem; color: #fff; background: var(--swatch); font: 700 0.72rem/1 Arial, Helvetica, sans-serif; }
.action-colour:nth-child(2) { color: #17201d; }
.group-presentation table { width: 100%; border-collapse: collapse; border-block: 1px solid var(--pattern-rule); font-size: 0.8rem; }
.group-presentation th, .group-presentation td { padding: 0.38rem 0.45rem; border-bottom: 1px solid var(--pattern-rule); text-align: left; vertical-align: top; }
.group-presentation th { color: var(--pattern-ink); font-weight: 500; }
.group-presentation tbody tr:last-child th, .group-presentation tbody tr:last-child td { border-bottom: 0; }
.generator-key { display: inline-block; min-width: 1.45rem; margin-right: 0.36rem; color: var(--pattern-accent); font-family: Georgia, "Times New Roman", serif; font-weight: 700; line-height: 1; }
.generator-geometry { color: var(--pattern-muted); line-height: 1.25; }
.presentation-permutation { color: var(--pattern-ink); font-family: Georgia, "Times New Roman", serif; font-weight: 700; white-space: nowrap; }
.presentation-identity { color: #9aa8a2; }
.seat-cell { width: 8rem; white-space: nowrap; }
.seat-flag { color: var(--pattern-seat); font-weight: 650; }
.presentation-relations { display: flex; gap: 0.6rem; margin: 0.5rem 0 0; color: var(--pattern-ink); font: 0.82rem/1.45 Georgia, "Times New Roman", serif; }
.presentation-relations strong { flex: 0 0 auto; color: var(--pattern-muted); font-family: Arial, Helvetica, sans-serif; font-size: 0.7rem; letter-spacing: 0.025em; }
.presentation-relations span { min-width: 0; overflow-wrap: anywhere; }

.pattern-invariant { margin: 0.9rem 0 0; padding: 0.7rem 0.85rem; border-left: 3px solid var(--pattern-seat); background: #fff7f4; border-radius: 0 0.4rem 0.4rem 0; }
.pattern-invariant h5 { margin: 0 0 0.35rem; font: 700 0.76rem/1.3 Arial, Helvetica, sans-serif; letter-spacing: 0.04em; text-transform: uppercase; color: var(--pattern-seat); }
.invariant-chain { margin: 0 0 0.4rem; font: 650 0.9rem/1.5 Georgia, "Times New Roman", serif; display: flex; flex-wrap: wrap; gap: 0.15rem 0.5rem; align-items: baseline; }
.chain-sep { color: #9a6c60; }
.invariant-text, .invariant-siblings { margin: 0.25rem 0 0; font-size: 0.82rem; line-height: 1.5; color: #3a2f2c; }
.invariant-siblings a { color: var(--pattern-accent); font-weight: 650; }

.book-evidence-link { color: #315d55; }
.lightbox { position: fixed; inset: 0; z-index: 200; background: rgba(20, 24, 22, 0.78); display: grid; place-items: center; padding: 1.5rem; }
.lightbox[hidden] { display: none; }
.lightbox-inner { background: #fff; border-radius: 0.6rem; padding: 0.8rem 0.9rem 0.6rem; max-width: min(96vw, 1100px); max-height: 92vh; overflow: auto; box-shadow: 0 20px 60px rgba(0,0,0,0.4); }
.lightbox-inner img { display: block; max-width: 100%; max-height: 78vh; margin: 0 auto; }
.lightbox-caption { margin: 0.5rem 0 0; font-size: 0.86rem; color: var(--pattern-muted); }
.lightbox-close { float: right; margin-top: 0.3rem; border: 1px solid var(--pattern-rule); background: var(--pattern-soft); border-radius: 0.35rem; padding: 0.25rem 0.6rem; font: 650 0.8rem/1 Arial, Helvetica, sans-serif; cursor: pointer; }
.noscript-note { padding: 1rem; border: 1px solid var(--pattern-rule); }

@media (max-width: 1050px) { .pane-body { grid-template-columns: 1fr; } }
@media (max-width: 760px) {
  main.tcp-page { width: min(100% - 1rem, 1560px); }
  .directory-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .family-header { grid-template-columns: 1fr; gap: 0.75rem; }
  .intro-figure { grid-template-columns: 1fr; }
}
@media (prefers-color-scheme: dark) {
  body.tcp { background: #fff; color: var(--pattern-ink); }
}
body.tcp header.site .title { color: var(--pattern-ink); }
body.tcp header.site nav a { color: var(--pattern-muted); }
body.tcp header.site nav a.here, body.tcp header.site nav a:hover { color: var(--pattern-accent); }
body.tcp footer.site { color: var(--pattern-muted); }