/* tactilecubing.com: a calm reference page. Text first; the look is a layer.
   Layout: one reading column, ~65ch; tables scroll inside their own box. */
@font-face { font-family: "Atkinson Hyperlegible"; font-weight: 400; font-display: swap; src: url("/fonts/atkinson-400.woff2") format("woff2"); }
@font-face { font-family: "Atkinson Hyperlegible"; font-weight: 700; font-display: swap; src: url("/fonts/atkinson-700.woff2") format("woff2"); }
@font-face { font-family: "Literata"; font-weight: 200 900; font-display: swap; src: url("/fonts/literata.woff2") format("woff2"); }
@font-face { font-family: "Literata"; font-style: italic; font-weight: 400; font-display: swap; src: url("/fonts/literata-italic.woff2") format("woff2"); }

:root {
  --stone: #eef0ed;      /* page: cool, unbleached stone */
  --ink: #1a1d1c;
  --muted: #565d5a;
  --rule: #cfd5d1;
  --well: #e2e6e2;       /* recessed surfaces: the contents box */
  --accent: #2f5f63;     /* deep slate teal */
  --measure: 40rem;
  --text: "Literata", "Iowan Old Style", Georgia, serif;
  --ui: "Atkinson Hyperlegible", system-ui, -apple-system, "Segoe UI", sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --stone: #151817; --ink: #e6e9e6; --muted: #a1aaa6; --rule: #343a38;
    --well: #1f2422; --accent: #8cc3c4; color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --stone: #151817; --ink: #e6e9e6; --muted: #a1aaa6; --rule: #343a38;
  --well: #1f2422; --accent: #8cc3c4; color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--stone);
  color: var(--ink);
  font: 1.125rem/1.7 var(--text);
}
a { color: var(--accent); text-underline-offset: 0.18em; }
a:focus-visible, summary:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }

.skip { position: absolute; left: -999px; }
.skip:focus { left: 1rem; top: 1rem; background: var(--stone); padding: 0.5rem 1rem; }


.column {
  max-width: calc(var(--measure) + 2rem);
  margin: 0 auto;
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(16px, env(safe-area-inset-right, 0px));
}
header.site { padding-block: 3rem 0; }
.wordmark { display: inline-flex; flex-direction: column; gap: 0.2rem; text-decoration: none; color: var(--muted); }
.wordmark span { font: 700 0.85rem/1 var(--ui); letter-spacing: 0.14em; text-transform: uppercase; }
.wordmark .braille { font-size: 1.1rem; letter-spacing: 0.1em; color: var(--accent); }

h1, h2, h3 { font-family: var(--ui); text-wrap: balance; }
h1 { font-size: 2.75rem; line-height: 1.08; margin: 2.25rem 0 1rem; font-weight: 700; }
h2 { font-size: 1.6rem; line-height: 1.2; margin: 3.5rem 0 1rem; font-weight: 700; }
h3 { font-size: 1.2rem; line-height: 1.3; margin: 2rem 0 0.5rem; font-weight: 700; }
.definition { font-size: 1.35rem; line-height: 1.5; }
.meta { font: 0.85rem/1.45 var(--ui); color: var(--muted); }

nav.toc { margin: 2.5rem 0; padding: 1rem 1.25rem; background: var(--well); border-radius: 4px; }
nav.toc h2 { margin: 0 0 0.5rem; font: 700 0.8rem/1 var(--ui); letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted); }
nav.toc ol { margin: 0; padding-left: 1.4rem; font: 0.95rem/1.85 var(--ui); }

.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font: 0.92rem/1.45 var(--ui); margin: 1rem 0; }
caption { text-align: left; }
th, td { text-align: left; vertical-align: top; padding: 0.55rem 0.5rem; border-bottom: 1px solid var(--rule); }
th { font-weight: 700; }




details { border-top: 1px solid var(--rule); padding-block: 0.75rem; }
details:last-of-type { border-bottom: 1px solid var(--rule); }
summary { cursor: pointer; font: 700 1rem/1.4 var(--ui); }

dl.glossary dt { font: 700 1rem/1.4 var(--ui); margin-top: 1rem; }
dl.glossary dd { margin: 0.25rem 0 0; }

.disclosure {
  font: 0.92rem/1.55 var(--ui);
  border-left: 3px solid var(--accent);
  padding: 0.25rem 0 0.25rem 1rem;
  margin: 1.5rem 0;
}
.disclosure h2 { margin: 0 0 0.25rem; }



footer.site { margin-top: 5rem; padding-block: 1.5rem 4rem; border-top: 1px solid var(--rule); font: 0.85rem/1.6 var(--ui); color: var(--muted); }

@media (max-width: 30rem) {
  body { font-size: 1.0625rem; }
  h1 { font-size: 2.1rem; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

/* v2: the treatise */
.hero { padding-block: 0 0.5rem; }
.hero h1 { font-size: 3.4rem; margin-bottom: 0.25rem; letter-spacing: -0.01em; }
.thesis { font: 400 1.6rem/1.3 var(--text); font-style: italic; color: var(--accent); margin: 0 0 1.75rem; text-wrap: balance; }
.num {
  display: block;
  font: 700 0.8rem/1 var(--ui);
  letter-spacing: 0.18em;
  color: var(--accent);
  margin-bottom: 0.6rem;
}
.pull {
  font: 400 1.4rem/1.45 var(--text);
  font-style: italic;
  margin: 2rem 0;
  padding-left: 1.25rem;
  border-left: 2px solid var(--accent);
  text-wrap: balance;
}
.toc-part { margin: 0.9rem 0 0.25rem; font: 700 0.8rem/1 var(--ui); letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted); }

h2.part { font-size: 0.9rem; letter-spacing: 0.14em; text-transform: uppercase; color: var(--muted); margin: 1.5rem 0 0; }
@media (max-width: 30rem) {
  .hero h1 { font-size: 2.5rem; }
  .thesis { font-size: 1.3rem; }
  .pull { font-size: 1.2rem; }
}

/* launch */
.formats { font: 0.9rem/1.5 var(--ui); color: var(--muted); }
.disclosure-inline { font: 0.92rem/1.5 var(--ui); color: var(--muted); }
hr.part-break { border: 0; height: 1px; background: var(--rule); margin: 5rem 0 0; }
#faq h3 { font-size: 1.05rem; margin-top: 1.5rem; }
@media (forced-colors: active) {
  .pull, .disclosure { border-left-color: CanvasText; }
  hr.part-break { background: CanvasText; }
  nav.toc { border: 1px solid CanvasText; }
}
@media (prefers-contrast: more) {
  :root { --muted: var(--ink); --rule: var(--ink); }
}
.table-wrap:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }