/* Kyllo website — plain CSS, no framework. Single reading column, sticky nav.
   Dark hero, light content. Restrained black/white/grey. No gradients. */
:root {
  --ink: #1a1a1a;
  --ink-soft: #3d3d3d;
  --muted: #5c5c5c;
  --paper: #ffffff;
  --paper-soft: #f4f4f2;
  --line: #d9d9d6;
  --dark: #111111;
  --dark-soft: #1e1e1e;
  --focus: #005fcc;
  --max: 44rem;
  --pad: 1.25rem;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 1.0625rem;
  line-height: 1.65;
}
h1, h2, h3 { line-height: 1.25; letter-spacing: -0.01em; }
h1 { font-size: 2rem; margin: 0 0 0.5rem; }
h2 { font-size: 1.5rem; margin: 2.5rem 0 0.75rem; padding-top: 1.5rem; border-top: 1px solid var(--line); }
h2:first-of-type { border-top: 0; padding-top: 0; margin-top: 0; }
h3 { font-size: 1.15rem; margin: 1.75rem 0 0.5rem; }
p { margin: 0 0 1rem; }
a { color: var(--ink); text-decoration: underline; text-underline-offset: 0.15em; }
a:hover { color: #000; }
ul, ol { margin: 0 0 1rem; padding-left: 1.4rem; }
li { margin-bottom: 0.35rem; }
code, pre { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace; }
code { font-size: 0.92em; background: var(--paper-soft); padding: 0.1em 0.3em; border-radius: 3px; }
pre {
  background: var(--dark);
  color: #f2f2f2;
  padding: 1rem 1.1rem;
  overflow-x: auto;
  border-radius: 4px;
  font-size: 0.9rem;
  line-height: 1.55;
  margin: 0 0 1rem;
}
pre code { background: transparent; padding: 0; color: inherit; }
img { max-width: 100%; height: auto; }

/* Skip link */
.skip-link {
  position: absolute; left: -999px; top: 0;
  background: var(--ink); color: #fff; padding: 0.6rem 1rem; z-index: 100;
}
.skip-link:focus { left: 0.5rem; top: 0.5rem; color: #fff; }

/* Header / nav — sticky, dark, mascot mark */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: var(--dark); color: #fff;
  border-bottom: 1px solid #333;
}
.site-header .wrap {
  max-width: 72rem; margin: 0 auto; padding: 0.6rem var(--pad);
  display: flex; align-items: center; gap: 1rem; flex-wrap: wrap;
}
.brand { display: flex; align-items: center; gap: 0.6rem; color: #fff; text-decoration: none; font-weight: 700; font-size: 1.15rem; }
.brand img { width: 2rem; height: 2rem; display: block; }
.brand:hover { color: #fff; }
.nav-toggle {
  margin-left: auto; background: transparent; color: #fff;
  border: 1px solid #666; border-radius: 4px; padding: 0.4rem 0.7rem;
  font: inherit; font-size: 0.95rem; cursor: pointer; display: none;
}
.site-nav { margin-left: auto; }
.site-nav ul { display: flex; gap: 0.25rem; list-style: none; margin: 0; padding: 0; flex-wrap: wrap; }
.site-nav a { color: #e8e8e8; text-decoration: none; padding: 0.4rem 0.65rem; border-radius: 4px; font-size: 0.98rem; }
.site-nav a:hover { color: #fff; background: var(--dark-soft); }
.site-nav a[aria-current="page"] { color: #fff; background: var(--dark-soft); text-decoration: underline; text-underline-offset: 0.2em; }

/* Layout */
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 var(--pad); }
main .wrap { padding-top: 2.25rem; padding-bottom: 3rem; }
.lede { font-size: 1.2rem; line-height: 1.6; color: var(--ink-soft); }

/* Hero — dark, mascot, brand language */
.hero { background: var(--dark); color: #fff; }
.hero .wrap { padding-top: 3rem; padding-bottom: 3rem; text-align: left; }
.hero img { width: 11rem; height: 11rem; display: block; margin-bottom: 1.25rem; }
.hero h1 { font-size: 2.6rem; margin-bottom: 0.25rem; }
.hero .motto { font-size: 1.35rem; font-weight: 700; margin: 0 0 0.5rem; }
.hero .sub { color: #c9c9c9; margin-bottom: 1.5rem; }
.hero p { color: #e8e8e8; }
.hero a { color: #fff; }
.hero .button { display: inline-block; background: #fff; color: var(--dark); text-decoration: none; font-weight: 700; padding: 0.65rem 1.1rem; border-radius: 4px; }
.hero .button:hover { background: #e8e8e8; color: #000; }
.hero .button-secondary { background: transparent; color: #fff; border: 1px solid #888; font-weight: 400; margin-left: 0.6rem; }
.hero .button-secondary:hover { background: var(--dark-soft); color: #fff; }
.hero .note { font-size: 0.92rem; color: #bdbdbd; margin-top: 1.25rem; }

/* Status labels — visible text, never colour alone */
.status {
  display: inline-block; font-size: 0.78rem; font-weight: 700; letter-spacing: 0.04em;
  text-transform: uppercase; border: 1px solid currentColor; border-radius: 3px;
  padding: 0.1rem 0.45rem; margin-right: 0.4rem; vertical-align: middle;
}
.status-accepted { color: #14532d; background: #eef7f0; }
.status-proposed { color: #5b3a00; background: #fdf6e3; }
.status-unresolved { color: #7a1f1f; background: #fdf0f0; }
.status-checked { color: #14532d; background: #eef7f0; }
.status-unverified { color: #5b3a00; background: #fdf6e3; }
.status-failed { color: #7a1f1f; background: #fdf0f0; }
.hero .status { color: #fff; background: transparent; }

/* Panels — plain bordered boxes, not cards-as-decoration */
.panel { border: 1px solid var(--line); border-left: 4px solid var(--ink); background: var(--paper-soft); padding: 1rem 1.2rem; margin: 1.5rem 0; border-radius: 0 4px 4px 0; }
.panel h2, .panel h3 { border: 0; padding: 0; margin-top: 0; }
.panel p:last-child, .panel ul:last-child { margin-bottom: 0; }
.panel-dark { background: var(--dark); color: #f2f2f2; border-color: #333; border-left-color: #fff; }
.panel-dark h2, .panel-dark h3 { color: #fff; }
.panel-dark p, .panel-dark li { color: #e8e8e8; }
.panel-dark code { background: #2a2a2a; color: #f2f2f2; }
.example-label { font-size: 0.85rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); margin: 1.5rem 0 0.4rem; }
.example-label .status { margin-left: 0.3rem; }

/* Definition list for verification levels */
.levels { margin: 0 0 1rem; }
.levels dt { font-weight: 700; margin-top: 1rem; }
.levels dd { margin: 0.25rem 0 0; }

/* Tables */
table { width: 100%; border-collapse: collapse; margin: 0 0 1.25rem; font-size: 0.95rem; }
th, td { text-align: left; padding: 0.55rem 0.6rem; border-bottom: 1px solid var(--line); vertical-align: top; }
th { font-weight: 700; }
tbody tr:last-child th, tbody tr:last-child td { border-bottom: 0; }

/* Footer — light, black mascot */
.site-footer { border-top: 1px solid var(--line); background: var(--paper-soft); }
.site-footer .wrap { padding-top: 2rem; padding-bottom: 2rem; max-width: var(--max); }
.site-footer img { width: 3rem; height: 3rem; display: block; margin-bottom: 0.75rem; }
.site-footer p { font-size: 0.92rem; color: var(--muted); margin-bottom: 0.5rem; }
.site-footer a { color: var(--ink-soft); }

/* Focus — always visible */
a:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 3px solid var(--focus); outline-offset: 2px; border-radius: 2px;
}
.hero a:focus-visible, .site-header a:focus-visible, .site-header button:focus-visible { outline-color: #fff; }

/* Responsive */
@media (max-width: 640px) {
  body { font-size: 1rem; }
  h1 { font-size: 1.7rem; }
  .hero h1 { font-size: 2.1rem; }
  .hero img { width: 8rem; height: 8rem; }
  .nav-toggle { display: block; }
  .site-nav { display: none; width: 100%; margin-left: 0; }
  .site-nav.open { display: block; }
  .site-nav ul { flex-direction: column; gap: 0; }
  .site-nav a { display: block; padding: 0.6rem 0.2rem; }
  .hero .button-secondary { margin-left: 0; margin-top: 0.6rem; }
  table { font-size: 0.88rem; }
}
@media (min-width: 641px) {
  .site-nav { display: block !important; }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}