/*
 * posse-bliki styles, built on JC's a11y Design System (spec/design.md).
 *
 * Token values are copied from the system's tokens/*.css. Use the semantic
 * tokens (--text-*, --surface-*, --border-*) in rules below, not the
 * primitives (--blue-700 and friends), so a palette change touches one place.
 * Fonts are self-hosted from /fonts/ (no third-party requests).
 */

/* --- fonts (SIL OFL 1.1; licences sit beside the files) --- */
@font-face {
  font-family: "Atkinson Hyperlegible Next";
  font-style: normal;
  font-weight: 200 800;
  font-display: swap;
  src: url("fonts/atkinson-hyperlegible-next-latin.woff2") format("woff2");
}
@font-face {
  font-family: "Atkinson Hyperlegible Next";
  font-style: italic;
  font-weight: 200 800;
  font-display: swap;
  src: url("fonts/atkinson-hyperlegible-next-italic-latin.woff2") format("woff2");
}
@font-face {
  font-family: "JetBrains Mono";
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url("fonts/jetbrains-mono-latin.woff2") format("woff2");
}

/* --- colour: primitives (OKLCH, one lightness ladder for every hue) --- */
:root {
  --paper: oklch(0.985 0.004 91.4);
  --white: oklch(1 0 0);
  --sand-50: oklch(0.965 0.007 89);
  --sand-100: oklch(0.93 0.011 89);
  --sand-200: oklch(0.87 0.014 89);
  --ink-900: oklch(0.255 0.018 260.7);
  --ink-700: oklch(0.425 0.018 260.7);
  --ink-500: oklch(0.525 0.018 260.7);
  --blue-900: oklch(0.255 0.083 254.5);
  --blue-700: oklch(0.425 0.13 254.5);
  --blue-50: oklch(0.965 0.011 254.5);
  --yellow-focus: oklch(0.879 0.162 90.9);
}
/* Browsers without OKLCH get the same palette in hex. */
@supports not (color: oklch(0 0 0)) {
  :root {
    --paper: #fbfaf7;
    --white: #ffffff;
    --sand-50: #f5f3ee;
    --sand-100: #ebe8e0;
    --sand-200: #d8d4ca;
    --ink-900: #1e232c;
    --ink-700: #494f59;
    --ink-500: #646b75;
    --blue-900: #002249;
    --blue-700: #0b4e93;
    --blue-50: #eff4fb;
    --yellow-focus: #ffd23f;
  }
}

/* --- colour: semantic (light). Text pairs meet WCAG AAA 7:1. --- */
:root {
  --text-1: var(--ink-900);
  --text-2: var(--ink-700);
  --text-link: var(--blue-700);
  --text-link-hover: var(--blue-900);
  --surface-page: var(--paper);
  --surface-card: var(--white);
  --surface-sunken: var(--sand-50);
  --surface-selected: var(--blue-50);
  --border-strong: var(--ink-500);
  --border-subtle: var(--sand-200);
  --focus-halo: var(--yellow-focus);
  --focus-ring: var(--ink-900);
  --badge-neutral-bg: var(--sand-100);
  --badge-neutral-border: var(--sand-200);
  color-scheme: light dark;
}
/* Dark follows the operating system. Accents at L 0.795, tints at L 0.28. */
@media (prefers-color-scheme: dark) {
  :root {
    --text-1: oklch(0.943 0.007 88.6);
    --text-2: oklch(0.808 0.009 91.5);
    --text-link: oklch(0.795 0.104 253.8);
    --text-link-hover: oklch(0.889 0.055 255.2);
    --surface-page: oklch(0.204 0.009 264.4);
    --surface-card: oklch(0.251 0.012 264.3);
    --surface-sunken: oklch(0.181 0.007 258.4);
    --surface-selected: oklch(0.286 0.044 255.6);
    --border-strong: oklch(0.704 0.016 260.7);
    --border-subtle: oklch(0.336 0.015 264.3);
    --focus-halo: oklch(0.879 0.162 90.9);
    --focus-ring: oklch(1 0 0);
    --badge-neutral-bg: oklch(0.3 0.014 261.7);
    --badge-neutral-border: oklch(0.367 0.017 262.3);
  }
}

/* --- type: 18px base, ~1.25 ratio, nothing below 16px --- */
:root {
  --font-sans: "Atkinson Hyperlegible Next", "Atkinson Hyperlegible", Verdana, "Segoe UI", system-ui, -apple-system, Roboto, "Noto Sans", Ubuntu, Cantarell, "DejaVu Sans", sans-serif;
  --font-code: "JetBrains Mono", "Atkinson Hyperlegible Mono", ui-monospace, "SF Mono", Menlo, Consolas, "DejaVu Sans Mono", monospace;
  --size-sm: 1rem;
  --size-base: 1.125rem;
  --size-lg: 1.375rem;
  --size-xl: 1.75rem;
  --size-2xl: 2.125rem;
  --size-3xl: 2.625rem;
  --weight-regular: 400;
  --weight-bold: 700;
  --weight-heavy: 800;
  --leading-tight: 1.2;
  --leading-snug: 1.35;
  --leading-body: 1.6;
  --tracking-body: 0.01em;
  --tracking-display: -0.01em;
  --para-space: 1em;
  --measure: 66ch;
}

/* --- space, shape, motion --- */
:root {
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
  --target-min: 44px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-pill: 999px;
  --focus-outline: 0 0 0 3px var(--focus-halo), 0 0 0 6px var(--focus-ring);
  --duration-fast: 120ms;
  --ease-out: cubic-bezier(.2, .7, .3, 1);
}
@media (prefers-reduced-motion: reduce) {
  :root { --duration-fast: 0ms; }
}
/* More contrast asked for: secondary text and hairlines go to full strength. */
@media (prefers-contrast: more) {
  :root {
    --text-2: var(--text-1);
    --border-subtle: var(--border-strong);
  }
}

/* --- element defaults --- */
*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-padding-block: var(--space-8);
}
body {
  margin: 0;
  background: var(--surface-page);
  color: var(--text-1);
  font: var(--weight-regular) var(--size-base)/var(--leading-body) var(--font-sans);
  letter-spacing: var(--tracking-body);
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3, h4 {
  margin: var(--space-6) 0 var(--space-3);
  font-family: var(--font-sans);
  font-weight: var(--weight-bold);
  text-wrap: balance;
  color: var(--text-1);
}
h1 { font-size: var(--size-3xl); line-height: var(--leading-tight); letter-spacing: var(--tracking-display); margin-top: 0; }
h2 { font-size: var(--size-2xl); line-height: var(--leading-tight); }
h3 { font-size: var(--size-xl); line-height: var(--leading-snug); }
h4 { font-size: var(--size-lg); line-height: var(--leading-snug); }
p, li { max-width: var(--measure); text-wrap: pretty; }
p { margin: 0 0 var(--para-space); }
ul, ol { padding-inline-start: var(--space-5); }
li + li { margin-top: var(--space-1); }
strong, b { font-weight: var(--weight-bold); }
a {
  color: var(--text-link);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: .2em;
}
a:hover { color: var(--text-link-hover); text-decoration-thickness: 3px; }
:focus-visible {
  outline: none;
  box-shadow: var(--focus-outline);
  border-radius: var(--radius-sm);
}
::selection { background: var(--yellow-focus); color: var(--ink-900); }
img { max-width: 100%; height: auto; border-radius: var(--radius-md); }
hr { border: 0; border-top: 1px solid var(--border-subtle); margin: var(--space-7) 0; }

/* Code: slashed zero, fixed-width digits, no ligatures (!= stays !=). */
code, kbd, pre, samp {
  font-family: var(--font-code);
  font-size: var(--size-sm);
  font-variant-numeric: slashed-zero tabular-nums;
  font-variant-ligatures: none;
  letter-spacing: 0;
}
:not(pre) > code {
  padding: .1em .35em;
  background: var(--surface-sunken);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
}
pre {
  max-width: 100%;
  overflow-x: auto;
  margin: 0 0 var(--para-space);
  padding: var(--space-4);
  background: var(--surface-sunken);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  line-height: var(--leading-body);
}

blockquote {
  margin: 0 0 var(--para-space);
  padding-inline-start: var(--space-4);
  border-inline-start: 4px solid var(--border-subtle);
  color: var(--text-2);
}

table {
  display: block;
  max-width: 100%;
  overflow-x: auto;
  border-collapse: collapse;
  margin: 0 0 var(--para-space);
}
th, td {
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--border-subtle);
  text-align: start;
  vertical-align: top;
}
th { background: var(--surface-sunken); font-weight: var(--weight-bold); }

/* Windows contrast themes strip box-shadow, so focus needs a real outline. */
@media (forced-colors: active) {
  :focus-visible { outline: 3px solid Highlight; outline-offset: 3px; }
}

/* --- page layout: one left-aligned column, text measure 66ch --- */
.site-header, main, .site-footer {
  max-width: calc(var(--measure) + 2 * var(--space-5));
  margin-inline: auto;
  padding-inline: var(--space-5);
}

/* Hidden until focused, then the first thing a keyboard user lands on. */
.skip-link {
  position: absolute;
  inset-block-start: var(--space-2);
  inset-inline-start: var(--space-2);
  z-index: 1;
  padding: var(--space-2) var(--space-4);
  background: var(--surface-card);
  font-weight: var(--weight-bold);
  transform: translateY(-200%);
}
.skip-link:focus { transform: none; }

.site-header {
  padding-block: var(--space-5) var(--space-6);
}
.site-header nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-5);
}
.site-header nav a {
  display: inline-flex;
  align-items: center;
  min-height: var(--target-min);
}
.site-header .site-title {
  margin-inline-end: auto;
  color: var(--text-1);
  font-weight: var(--weight-heavy);
  font-size: var(--size-lg);
  text-decoration: none;
}
.site-header .site-title:hover { text-decoration: underline; }
/* Narrow screens: the title gets its own row, the links share the next. */
@media (max-width: 40rem) {
  .site-header .site-title { flex-basis: 100%; }
}

main { padding-block-end: var(--space-7); }

.site-footer {
  padding-block: var(--space-5) var(--space-7);
  color: var(--text-2);
}
.site-footer p {
  max-width: none;
  padding-block-start: var(--space-5);
  border-block-start: 1px solid var(--border-subtle);
}

/* --- notes (h-entry) --- */
.h-entry > header { margin-bottom: var(--space-6); }
.meta, .p-summary { color: var(--text-2); }
.meta { font-size: var(--size-sm); }
.meta a { color: inherit; }
.h-entry > header .p-summary { font-size: var(--size-lg); }
.e-content > :first-child { margin-top: 0; }
.e-content h1 { font-size: var(--size-2xl); margin-top: var(--space-6); }

/* Tags: static pill tags, at least 44px tall so they are easy to hit. */
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  max-width: none;
}
.tags a {
  display: inline-flex;
  align-items: center;
  min-height: var(--target-min);
  padding-inline: 14px;
  border: 2px solid var(--border-strong);
  border-radius: var(--radius-pill);
  background: var(--surface-card);
  color: var(--text-1);
  font-size: var(--size-sm);
  text-decoration: none;
  transition: background-color var(--duration-fast) var(--ease-out);
}
.tags a:hover { background: var(--surface-selected); border-color: var(--text-1); }

.h-entry > footer {
  margin-top: var(--space-7);
  color: var(--text-2);
}

/* --- lists of notes (h-feed) and backlinks --- */
.h-feed ul, .backlinks ul {
  list-style: none;
  padding: 0;
  margin: 0;
}
.h-feed li, .backlinks li {
  max-width: none;
  margin: 0;
  padding-block: var(--space-3);
  border-bottom: 1px solid var(--border-subtle);
}
.h-feed li > a { font-weight: var(--weight-bold); }
.h-feed time, .h-feed .p-summary { color: var(--text-2); }
.h-feed time {
  margin-inline-start: var(--space-2);
  font-size: var(--size-sm);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.h-card { margin-bottom: var(--space-6); }
.h-card p { display: flex; flex-wrap: wrap; gap: var(--space-2) var(--space-4); }
.h-card .p-name { font-weight: var(--weight-bold); }

.backlinks {
  margin-top: var(--space-7);
  padding: var(--space-5);
  background: var(--surface-sunken);
  border-radius: var(--radius-md);
}
.backlinks h2 {
  margin: 0 0 var(--space-2);
  font-size: var(--size-lg);
}
.backlinks li:last-child { border-bottom: 0; }

/* --- received webmentions (spec/indieweb.md) --- */
.webmentions {
  margin-top: var(--space-7);
  padding-top: var(--space-5);
  border-top: 1px solid var(--border-subtle);
}
.webmentions h2 {
  margin: 0 0 var(--space-3);
  font-size: var(--size-lg);
}
.webmentions ol {
  list-style: none;
  padding: 0;
  margin: 0;
}
.webmentions li {
  max-width: none;
  margin: 0;
  padding-block: var(--space-3);
  border-bottom: 1px solid var(--border-subtle);
}
.webmentions li p { margin-bottom: var(--space-1); }
.webmentions time { color: var(--text-2); font-size: var(--size-sm); }
.webmentions .p-content { color: var(--text-2); }