/* ===========================================================================
   KUAS Open Source Circle
   A plain, document-style stylesheet in the old-school free-software idiom:
   one narrow column, serif text, honest links. No frameworks, no JS needed.
   =========================================================================== */

:root {
  --bg:           #fbfaf6;   /* warm paper */
  --bg-code:      #f1efe7;   /* slightly darker paper for code */
  --text:         #1c1b18;
  --muted:        #5c5a52;
  --faint:        #87857b;
  --link:         #1a3ea8;   /* classic blue */
  --link-visited: #6a3a9a;   /* and the classic visited purple */
  --rule:         #d9d5c7;   /* hairlines, warm grey */
  --mark:         #b54b00;   /* rare accent: brick orange */
  --serif: "Charter", "Iowan Old Style", "Palatino Linotype", Palatino,
           Georgia, "Liberation Serif", "Times New Roman",
           "Hiragino Mincho ProN", "Yu Mincho", "MS PMincho", serif;
  --mono: "DejaVu Sans Mono", "Liberation Mono", "SFMono-Regular",
          Menlo, Consolas, monospace;
  --measure: 42rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg:           #17181b;
    --bg-code:      #20221f;
    --text:         #dcdacf;
    --muted:        #a3a194;
    --faint:        #807e72;
    --link:         #8fb1f2;
    --link-visited: #c4a6ea;
    --rule:         #34362f;
    --mark:         #e08a4a;
  }
}

/* ---- base --------------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--serif);
  font-size: 19px;
  line-height: 1.6;
  text-rendering: optimizeLegibility;
}

/* The whole page is a single readable column. */
.wrap {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 0 1.4rem;
}

/* The homepage is wider, to make room for the sidebar + article column. */
.wrap-wide { max-width: 64rem; }

/* ---- links -------------------------------------------------------------- */
a { color: var(--link); }
a:visited { color: var(--link-visited); }
a:hover { color: var(--mark); }
a:focus-visible { outline: 2px solid var(--mark); outline-offset: 2px; }

.skip-link {
  position: absolute; left: -9999px; top: 0;
  background: var(--text); color: var(--bg); padding: .4rem .8rem;
}
.skip-link:focus { left: .5rem; top: .5rem; z-index: 10; }

/* ---- headings ----------------------------------------------------------- */
h1, h2, h3, h4 {
  font-family: var(--serif);
  font-weight: 700;
  line-height: 1.25;
  margin: 1.8rem 0 .6rem;
}
h1 { font-size: 1.8rem; margin-top: 1rem; }
h2 { font-size: 1.35rem; }
h3 { font-size: 1.12rem; }
h4 { font-size: 1rem; }

p, ul, ol, blockquote, pre, table, dl { margin: 0 0 1rem; }

hr {
  border: none;
  border-top: 1px solid var(--rule);
  margin: 1.5rem 0;
}

/* ---- site header -------------------------------------------------------- */
.masthead { padding-top: 1.6rem; }
.site-title {
  font-size: 1.7rem;
  font-weight: 700;
  margin: 0;
  letter-spacing: -0.01em;
}
.site-title a { color: var(--text); text-decoration: none; }
.site-title a:hover { color: var(--mark); }
.site-tagline {
  margin: .15rem 0 .7rem;
  color: var(--muted);
  font-style: italic;
  font-size: 1.02rem;
}
.nav {
  font-family: var(--mono);
  font-size: .82rem;
  padding-bottom: .9rem;
  border-bottom: 2px solid var(--rule);
}
.nav a { text-decoration: none; }
.nav a:hover { text-decoration: underline; }
.nav a[aria-current="page"] { color: var(--text); font-weight: 700; text-decoration: underline; }
.nav .sep { color: var(--faint); margin: 0 .15rem; }
.nav .lang-link { font-weight: 700; }

main { padding: 1.6rem 0 2.5rem; }

/* ---- homepage: small sidebar + river of latest articles ------------------ */
.home-grid {
  display: grid;
  grid-template-columns: 13rem minmax(0, 1fr);
  gap: 2.4rem;
  align-items: start;
}

.home-side {
  border-right: 1px solid var(--rule);
  padding-right: 1.8rem;
  font-size: .92rem;
}
.home-side h2 {
  font-size: .78rem;
  font-family: var(--mono);
  text-transform: uppercase;
  letter-spacing: .05em;
  color: var(--muted);
  margin: 1.4rem 0 .3rem;
}
.home-side .lead { font-size: .98rem; margin-bottom: .7rem; }
.home-side p { margin-bottom: .7rem; }
.home-side .side-fact { line-height: 1.45; }
.home-side .muted { color: var(--muted); font-size: .88rem; }
.home-side .more { margin: .2rem 0; }

.home-main { min-width: 0; }
.home-main-heading {
  margin-top: .3rem;
  font-size: .82rem;
  font-family: var(--mono);
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--muted);
  border-bottom: 1px solid var(--rule);
  padding-bottom: .5rem;
}
.home-post { margin: 0; }
.home-post-title { margin: 1.4rem 0 .2rem; font-size: 1.3rem; }
.home-post .byline { margin: 0 0 .9rem; }
.home-main hr { border-top: 1px solid var(--rule); margin: 1.6rem 0; }

@media (max-width: 40rem) {
  .home-grid { grid-template-columns: 1fr; gap: 0; }
  .home-side {
    border-right: none;
    border-bottom: 2px solid var(--rule);
    padding-right: 0;
    padding-bottom: 1.2rem;
    margin-bottom: 1.6rem;
  }
}

/* ---- page / article headers -------------------------------------------- */
.page-title { margin-top: .4rem; }
.lead {
  font-size: 1.12rem;
  color: var(--muted);
}
.byline {
  font-family: var(--mono);
  font-size: .8rem;
  color: var(--muted);
  margin: -.2rem 0 1.4rem;
}
.byline a { color: var(--muted); }
.byline a:visited { color: var(--muted); }
.byline a:hover { color: var(--mark); }
.crumb {
  font-family: var(--mono);
  font-size: .8rem;
  color: var(--faint);
  margin: 0 0 .3rem;
}
.draft-tag {
  font-family: var(--mono);
  font-size: .7rem;
  color: var(--mark);
  border: 1px solid var(--mark);
  padding: 0 .3rem;
  border-radius: 2px;
  text-transform: uppercase;
}

/* ---- the post list (the heart of an old-school blog) -------------------- */
.postlist { list-style: none; margin: 0 0 1.2rem; padding: 0; }
.postlist > li {
  margin: 0 0 1.1rem;
  padding: 0;
}
.postlist .date {
  font-family: var(--mono);
  font-size: .78rem;
  color: var(--faint);
  display: inline-block;
}
.postlist .ptitle {
  font-size: 1.08rem;
  font-weight: 700;
}
.postlist .psummary {
  color: var(--muted);
  font-size: .96rem;
  margin: .1rem 0 0;
}
.postlist .pmeta {
  font-family: var(--mono);
  font-size: .76rem;
  color: var(--faint);
}
.postlist .pmeta a { color: var(--faint); }
.postlist .pmeta a:visited { color: var(--faint); }

/* compact variant for the homepage "latest" list */
.postlist.compact > li {
  margin-bottom: .35rem;
  display: flex;
  gap: .8rem;
  align-items: baseline;
}
.postlist.compact .date { width: 6.2rem; flex: none; }

/* ---- simple feature/definition lists ------------------------------------ */
ul.plain { list-style: none; padding: 0; }
ul.plain > li { margin: 0 0 .7rem; padding-left: 1.1rem; position: relative; }
ul.plain > li::before { content: "\2022"; color: var(--mark); position: absolute; left: 0; }

dl.facts { margin: 0 0 1rem; }
dl.facts dt { font-weight: 700; }
dl.facts dd { margin: 0 0 .5rem; color: var(--muted); }

.tagline-list { font-family: var(--mono); font-size: .82rem; color: var(--muted); }
.tagline-list a { text-decoration: none; }
.tagline-list a:hover { text-decoration: underline; }

/* ---- prose (rendered Markdown) ----------------------------------------- */
.prose { }
.prose h2 { border-bottom: 1px solid var(--rule); padding-bottom: .15rem; }
.prose ul, .prose ol { padding-left: 1.5rem; }
.prose li { margin: .25rem 0; }
.prose img { max-width: 100%; height: auto; border: 1px solid var(--rule); }
.prose a { text-underline-offset: 2px; }

.prose blockquote {
  margin: 1rem 0;
  padding: .2rem 0 .2rem 1rem;
  border-left: 3px solid var(--rule);
  color: var(--muted);
  font-style: italic;
}
.prose blockquote p { margin: .4rem 0; }

.prose table {
  border-collapse: collapse;
  width: 100%;
  font-size: .92rem;
  display: block;
  overflow-x: auto;
}
.prose th, .prose td { border: 1px solid var(--rule); padding: .35rem .6rem; text-align: left; }
.prose thead th { background: var(--bg-code); }

.headerlink { text-decoration: none; color: var(--faint); margin-left: .35rem; opacity: 0; }
h2:hover .headerlink, h3:hover .headerlink, h4:hover .headerlink { opacity: 1; }

/* code: always on light parchment so it reads in either colour scheme */
code, pre, kbd, samp { font-family: var(--mono); }
.prose code {
  font-size: .85em;
  background: var(--bg-code);
  padding: .08em .35em;
  border-radius: 2px;
}
.prose pre {
  background: var(--bg-code);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--faint);
  padding: .8rem 1rem;
  overflow-x: auto;
  font-size: .82rem;
  line-height: 1.5;
}
.prose pre code { background: none; padding: 0; font-size: 1em; }
.highlight { background: var(--bg-code) !important; }

/* admonitions from python-markdown */
.admonition {
  border: 1px solid var(--rule);
  border-left: 3px solid var(--mark);
  background: var(--bg-code);
  padding: .6rem .9rem;
  margin: 1rem 0;
  font-size: .95rem;
}
.admonition-title { font-weight: 700; margin: 0 0 .25rem; }
.admonition.note { border-left-color: var(--link); }
.admonition p:last-child { margin-bottom: 0; }

/* table of contents on a post — a plain inset box */
.toc {
  border: 1px solid var(--rule);
  background: var(--bg-code);
  padding: .5rem .9rem;
  margin: 0 0 1.5rem;
  font-size: .9rem;
}
.toc-title { font-weight: 700; font-size: .8rem; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); }
.toc ul { margin: .2rem 0 0; padding-left: 1.2rem; }
.toc li { margin: .1rem 0; }
.toc a { text-decoration: none; }
.toc a:hover { text-decoration: underline; }

/* ---- prev / next -------------------------------------------------------- */
.post-nav {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 2rem;
  padding-top: .8rem;
  border-top: 1px solid var(--rule);
  font-size: .92rem;
}
.post-nav a { text-decoration: none; }
.post-nav a:hover { text-decoration: underline; }
.post-nav .label { font-family: var(--mono); font-size: .72rem; color: var(--faint); display: block; }
.post-nav .next { text-align: right; margin-left: auto; }

/* ---- footer ------------------------------------------------------------- */
.site-footer {
  border-top: 2px solid var(--rule);
  margin-top: 2rem;
  padding: 1rem 0 2.5rem;
  font-size: .82rem;
  color: var(--muted);
}
.site-footer a { color: var(--muted); }
.site-footer a:visited { color: var(--muted); }
.site-footer a:hover { color: var(--mark); }
.site-footer p { margin: .25rem 0; }
.site-footer .foot-links { font-family: var(--mono); }
.site-footer .sep { color: var(--faint); margin: 0 .2rem; }

/* ---- misc --------------------------------------------------------------- */
.more { font-family: var(--mono); font-size: .82rem; }
.more a { text-decoration: none; }
.more a:hover { text-decoration: underline; }
.empty { color: var(--muted); font-style: italic; }
mark, .hl { background: #fcf3a0; color: #1c1b18; }

@media (max-width: 34rem) {
  body { font-size: 18px; }
  .postlist.compact > li { display: block; }
  .postlist.compact .date { width: auto; }
}

/* ---- Japanese typography ------------------------------------------------- */
/* Longer line-height reads better for CJK body text than the Western 1.6
   default. :lang(ja) matches both a whole /ja/-tree page (via <html lang="ja">)
   and an embedded Japanese pane inside a bilingual post (via [lang="ja"]),
   since language is inherited down the DOM either way. */
.prose:lang(ja), .lead:lang(ja) { line-height: 1.9; }

/* ---- bilingual post toggle (no JS: the buttons are same-page anchors,
   and :target + :has() swap which language pane is visible) --------------- */
.lang-toggle {
  display: inline-flex;
  gap: .5rem;
  font-family: var(--mono);
  font-size: .78rem;
  margin: 0 0 1.3rem;
}
.lt-btn {
  display: inline-block;
  border: 1px solid var(--rule);
  padding: .15rem .65rem;
  border-radius: 2px;
  text-decoration: none;
}
.lt-btn:hover { border-color: var(--mark); color: var(--mark); }

.lang-pane[data-lang="ja"] { display: none; }
.lang-pair.default-ja .lang-pane[data-lang="ja"] { display: block; }
.lang-pair.default-ja .lang-pane[data-lang="en"] { display: none; }

body:has(#lang-ja:target) .lang-pane[data-lang="ja"] { display: block; }
body:has(#lang-ja:target) .lang-pane[data-lang="en"] { display: none; }
body:has(#lang-en:target) .lang-pane[data-lang="en"] { display: block; }
body:has(#lang-en:target) .lang-pane[data-lang="ja"] { display: none; }

body:has(#lang-ja:target) .lt-ja,
body:has(#lang-en:target) .lt-en {
  border-color: var(--text);
  font-weight: 700;
  text-decoration: underline;
}