/* hornbook.study (M2-T25, redesigned in M2-T30). System fonts only, no external resource, no script, no image reference in CSS.
   Colors follow the brand palette in brand/README.md: ink, mist, suit red, text and muted are the app tokens of
   app/src/theme/tokens.ts (C-37); paper, ink-deep and slate are brand-only. Dark mode follows prefers-color-scheme.
   Contrast of every text pair is checked against WCAG AA by scripts/tests/test_m2_t30_brand.py. */
:root {
  color-scheme: light dark;
  --ink: #1f3a5f;
  --ink-deep: #14263d;
  --paper: #f7f4ee;
  --mist: #9db4cc;
  --slate: #4a6a90;
  --margin: #b3261e;
  --surface: #ffffff;
  --surface-subtle: #f5f6f8;
  --surface-selected: #e3e8ef;
  --border: #c9ccd4;
  --text: #111111;
  --text-muted: #555555;
  --heading: #1f3a5f;
  --link: #1f3a5f;
  --card: #ffffff;
  --rule: rgba(31, 58, 95, 0.07);
  --header-bg: rgba(247, 244, 238, 0.92);
  --footer-bg: #14263d;
  --footer-text: #d5dee9;
  --footer-muted: #a9b6c6;
  --tile: #1f3a5f;
  --cell-p: #f7f4ee;
  --cell-s: #9db4cc;
  --cell-o: #4a6a90;
  --word: #1f3a5f;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, "Noto Serif", serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --sp-xs: 4px;
  --sp-sm: 8px;
  --sp-md: 12px;
  --sp-lg: 16px;
  --sp-xl: 24px;
  --sp-xxl: 32px;
  --r-sm: 4px;
  --r-md: 8px;
  --r-lg: 12px;
  --r-xl: 20px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #13202f;
    --margin: #e58a80;
    --surface: #0f1a28;
    --surface-subtle: #13202f;
    --surface-selected: #1b2c42;
    --border: #2c4060;
    --text: #e9edf3;
    --text-muted: #a9b6c6;
    --heading: #e9edf3;
    --link: #a9c4e4;
    --card: #15243a;
    --rule: rgba(169, 196, 228, 0.06);
    --header-bg: rgba(15, 26, 40, 0.92);
    --footer-bg: #0b1420;
    --tile: #f7f4ee;
    --word: #e9edf3;
  }
}

* { box-sizing: border-box; }
html { font-size: 100%; -webkit-text-size-adjust: 100%; scroll-padding-top: 6rem; }
body {
  margin: 0;
  background: var(--surface);
  color: var(--text);
  font-family: var(--sans);
  font-size: 1.0625rem;
  line-height: 1.6;
  text-rendering: optimizeLegibility;
}
a { color: var(--link); text-underline-offset: 0.15em; }
a:hover { text-decoration-thickness: 2px; }
a:focus-visible { outline: 3px solid var(--link); outline-offset: 3px; border-radius: var(--r-sm); }
p { margin: 0 0 var(--sp-md); }
strong { font-weight: 650; }
.wrap { max-width: 72rem; margin: 0 auto; padding: 0 1.25rem; }

h1, h2, h3 { font-family: var(--serif); color: var(--heading); font-weight: 600; }
h1 { font-size: 2.25rem; line-height: 1.12; letter-spacing: -0.01em; margin: 0 0 var(--sp-lg); }
h2 { font-size: 1.75rem; line-height: 1.2; margin: 0 0 var(--sp-lg); }
h3 { font-size: 1.1875rem; line-height: 1.3; margin: 0 0 var(--sp-sm); }

/* Brand lockup (inline SVG from brand/svg/site-lockup.svg). On dark surfaces the tile turns to paper. */
.brand { display: inline-flex; line-height: 0; border-radius: var(--r-md); }
.hb-lockup { height: 30px; width: auto; }
.hb-tile { fill: var(--tile); }
.hb-c0 { fill: var(--cell-p); }
.hb-c1 { fill: var(--cell-s); }
.hb-c2 { fill: var(--cell-o); }
.hb-word { fill: var(--word); }
@media (prefers-color-scheme: dark) {
  .hb-c0 { fill: var(--ink); }
  .hb-c1 { fill: var(--slate); }
  .hb-c2 { fill: var(--mist); }
}

/* Header */
header.site {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--header-bg);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--border);
}
header.site .wrap { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: var(--sp-sm) var(--sp-xl); padding-top: var(--sp-md); padding-bottom: var(--sp-sm); }
nav { width: 100%; }
nav ul { list-style: none; margin: 0; padding: 0; display: flex; gap: var(--sp-xs) 14px; overflow-x: auto; white-space: nowrap; scrollbar-width: none; }
nav ul::-webkit-scrollbar { display: none; }
nav li { margin: 0; }
nav a { display: inline-block; padding: var(--sp-sm) 0; font-size: 0.875rem; color: var(--text); text-decoration: none; }
nav a:hover { color: var(--link); text-decoration: underline; }
nav a.lang { font-weight: 600; color: var(--link); }

/* Hero */
.hero {
  background-color: var(--paper);
  background-image: repeating-linear-gradient(to bottom, transparent 0, transparent 31px, var(--rule) 31px, var(--rule) 32px);
  border-bottom: 1px solid var(--border);
  padding: 2.5rem 0 3rem;
}
.hero-grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: 2.5rem; align-items: center; }
.tagline {
  display: flex;
  align-items: center;
  gap: var(--sp-md);
  font-size: 0.8125rem;
  font-weight: 650;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin: 0 0 var(--sp-lg);
}
.tagline::before { content: ""; width: 28px; height: 2px; background: var(--margin); flex: none; }
.lede { font-size: 1.1875rem; line-height: 1.55; margin: 0 0 var(--sp-lg); }
.notice {
  background: var(--card);
  border: 1px solid var(--border);
  border-left: 4px solid var(--margin);
  border-radius: var(--r-md);
  padding: var(--sp-md) var(--sp-lg);
  margin: var(--sp-xl) 0;
}
.notice p { margin: var(--sp-xs) 0; }
.coming-soon {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-sm);
  margin: 0;
  padding: var(--sp-sm) var(--sp-lg);
  border: 1px solid var(--heading);
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.9375rem;
  color: var(--heading);
}
.coming-soon::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: var(--margin); }

/* Hand grid figure: structure only (pairs, suited, offsuit), never a frequency or an action color. */
.hand-grid { margin: 0; }
.hg {
  container-type: inline-size;
  display: grid;
  grid-template-columns: repeat(13, 1fr);
  gap: 2px;
  padding: 10px;
  background: var(--ink);
  border-radius: var(--r-xl);
  box-shadow: 0 1px 2px rgba(17, 17, 17, 0.08), 0 12px 32px rgba(31, 58, 95, 0.18);
}
.hg span {
  min-width: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 1;
  border-radius: 3px;
  font-size: 8px;
  font-size: 2.15cqi;
  font-weight: 600;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  line-height: 1;
}
.hg .p { background: var(--cell-p); color: var(--ink); }
.hg .s { background: var(--cell-s); color: var(--ink); }
.hg .o { background: var(--cell-o); color: var(--paper); }
@media (prefers-color-scheme: dark) {
  .hg .p { color: #1f3a5f; background: #f7f4ee; }
  .hg .o { color: #f7f4ee; }
  .hg { box-shadow: 0 0 0 1px var(--border); }
}
.hand-grid figcaption { display: flex; flex-wrap: wrap; align-items: center; gap: var(--sp-sm) var(--sp-lg); margin-top: var(--sp-md); font-size: 0.875rem; color: var(--text-muted); }
.key { display: inline-flex; align-items: center; gap: var(--sp-sm); }
.key::before { content: ""; width: 12px; height: 12px; border-radius: 3px; box-shadow: inset 0 0 0 1px rgba(17, 17, 17, 0.2); }
.key-p::before { background: #f7f4ee; }
.key-s::before { background: #9db4cc; }
.key-o::before { background: #4a6a90; }
.hg-note { flex-basis: 100%; }

/* Sections */
main section { padding: 3rem 0; }
main section + section { border-top: 1px solid var(--border); }
#private, #faq { background: var(--surface-subtle); }
ul, ol { padding-left: 1.25rem; margin: 0 0 var(--sp-md); }
li { margin: var(--sp-xs) 0; }

.features { list-style: none; padding: 0; margin: var(--sp-xl) 0 0; display: grid; gap: var(--sp-lg); counter-reset: feature; }
.features li {
  counter-increment: feature;
  margin: 0;
  padding: var(--sp-xl);
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
}
.features li::before {
  content: counter(feature, decimal-leading-zero);
  display: block;
  font-family: var(--serif);
  font-size: 0.9375rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  margin-bottom: var(--sp-md);
  padding-bottom: var(--sp-sm);
  border-bottom: 2px solid var(--margin);
  width: 2.25rem;
}
.features strong { display: block; font-family: var(--serif); font-size: 1.1875rem; line-height: 1.3; font-weight: 600; color: var(--heading); margin-bottom: var(--sp-xs); }

.provenance {
  margin-top: 2.5rem;
  padding: var(--sp-xl) var(--sp-xl) var(--sp-md) 1.75rem;
  background-color: var(--paper);
  background-image: repeating-linear-gradient(to bottom, transparent 0, transparent 27px, var(--rule) 27px, var(--rule) 28px);
  border-left: 3px solid var(--margin);
  border-radius: 0 var(--r-lg) var(--r-lg) 0;
}
.provenance h2 { font-size: 1.5rem; }

.checks { list-style: none; padding: 0; margin: 0 0 var(--sp-lg); }
.checks li { position: relative; padding: var(--sp-sm) 0 var(--sp-sm) 2rem; border-bottom: 1px solid var(--border); margin: 0; }
.checks li::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 0.85em;
  width: 7px;
  height: 13px;
  border: solid var(--link);
  border-width: 0 2.5px 2.5px 0;
  transform: rotate(45deg);
}

.plans { display: grid; gap: var(--sp-lg); margin: var(--sp-xl) 0; }
.plan { background: var(--card); border: 1px solid var(--border); border-radius: var(--r-lg); padding: var(--sp-xl); }
.plan p { margin: 0; }
.plan strong { display: block; font-family: var(--serif); font-size: 1.375rem; color: var(--heading); margin-bottom: var(--sp-xs); }
.plan-pro { border: 2px solid var(--heading); }

.table-scroll { overflow-x: auto; margin: var(--sp-lg) 0; border: 1px solid var(--border); border-radius: var(--r-lg); background: var(--card); }
table { border-collapse: collapse; width: 100%; min-width: 28rem; font-variant-numeric: tabular-nums; }
th, td { text-align: left; padding: var(--sp-md) var(--sp-lg); border-bottom: 1px solid var(--border); vertical-align: top; }
tbody tr:last-child th, tbody tr:last-child td { border-bottom: 0; }
thead th { background: var(--surface-selected); font-size: 0.875rem; font-weight: 650; }
tbody th { font-weight: 600; }
.small { color: var(--text-muted); font-size: 0.875rem; }
code { font-family: ui-monospace, Menlo, Consolas, monospace; font-size: 0.9em; background: var(--surface-subtle); padding: 0 var(--sp-xs); border-radius: var(--r-sm); }

.faq { display: grid; gap: var(--sp-lg) 3rem; margin-top: var(--sp-xl); }
.qa { border-top: 2px solid var(--border); padding-top: var(--sp-lg); }
.qa p { margin: 0; }

/* Footer */
footer.site { background: var(--footer-bg); color: var(--footer-text); padding: 3rem 0 2.5rem; font-size: 0.9375rem; }
footer.site a { color: #ffffff; display: inline-block; padding: var(--sp-xs) 0; }
footer.site .brand { margin-bottom: var(--sp-xl); }
footer.site .hb-tile { fill: #f7f4ee; }
footer.site .hb-c0 { fill: #1f3a5f; }
footer.site .hb-c1 { fill: #4a6a90; }
footer.site .hb-c2 { fill: #9db4cc; }
footer.site .hb-word { fill: #f7f4ee; }
footer.site ul { list-style: none; padding: 0 0 var(--sp-lg); margin: 0 0 var(--sp-lg); display: flex; gap: var(--sp-xs) var(--sp-xl); flex-wrap: wrap; border-bottom: 1px solid rgba(213, 222, 233, 0.2); }
footer.site p { max-width: 46rem; }
footer.site p:last-child { color: var(--footer-muted); margin: 0; }

/* Legal, support and 404 pages */
.legal .wrap, .hero .wrap:not(.hero-grid) { max-width: 46rem; }
.legal h1 { margin-top: 0; }
.legal h1 + p { color: var(--text-muted); font-size: 0.9375rem; padding-bottom: var(--sp-lg); border-bottom: 1px solid var(--border); }
.legal h2 { font-size: 1.375rem; margin-top: 2.25rem; }
.legal p, .legal li { overflow-wrap: anywhere; line-height: 1.7; }
.legal table { min-width: 34rem; }

@media (min-width: 40rem) {
  .wrap { padding: 0 2rem; }
  h1 { font-size: 3rem; line-height: 1.08; }
  h2 { font-size: 2.125rem; }
  .hero { padding: 4rem 0; }
  .lede { font-size: 1.3125rem; }
  .features { grid-template-columns: repeat(2, 1fr); }
  .plans { grid-template-columns: repeat(2, 1fr); }
  .faq { grid-template-columns: repeat(2, 1fr); }
  main section { padding: 4.5rem 0; }
  .hb-lockup { height: 34px; }
  nav ul { gap: var(--sp-xs) var(--sp-lg); }
  nav a { font-size: 0.9375rem; }
}

@media (min-width: 60rem) {
  header.site .wrap { flex-wrap: nowrap; padding-top: var(--sp-md); padding-bottom: var(--sp-md); }
  nav { width: auto; }
  nav ul { gap: var(--sp-xs) var(--sp-xl); }
  .hero-grid { grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr); gap: 4.5rem; }
  h1 { font-size: 3.5rem; }
  .features { grid-template-columns: repeat(3, 1fr); }
  .provenance { max-width: 50rem; }
  #private .wrap { display: grid; grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr); gap: 0 4rem; }
  #private .wrap > ul, #private .wrap > p { grid-column: 2; }
  #private .wrap > h2 { grid-row: 1 / span 2; }
}