/* ==========================================================================
   houkun theme — all styles live here.
   Rules: one accent (#c4b5fd). No new colors, fonts, shadows, radii or transitions.
   ========================================================================== */

:root {
  --bg: #f6f5f3;
  --ink: #111111;
  --text: #1d1c1a;
  --muted: #6d6a66;
  --accent: #c4b5fd;
  --code-bg: #e9e6f5;
  --hairline: #d8d5d0;
  --rule: 1px solid var(--ink);

  --sans: Helvetica, Arial, "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, Menlo, monospace;
}

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

html { scroll-behavior: auto; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
}

a { color: var(--ink); text-decoration: none; }
a:hover { color: var(--ink); background: var(--accent); }

.mono { font-family: var(--mono); }
.muted { color: var(--muted); }

.wrap {
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px clamp(20px, 4vw, 48px) 48px;
  display: flex;
  flex-direction: column;
}

/* ---------- Header ---------- */
.site-header {
  display: flex;
  flex-wrap: wrap;
  gap: 16px 32px;
  justify-content: space-between;
  align-items: baseline;
  border-bottom: var(--rule);
  padding-bottom: 14px;
  font-weight: 500;
  font-size: 13px;
}
.site-header .brand:hover { background: transparent; }
.site-header nav { display: flex; gap: 24px; flex-wrap: wrap; }
.site-header nav a.current { background: var(--accent); padding: 0 4px; }

/* ---------- Hero ---------- */
.hero {
  padding: clamp(48px, 8vw, 96px) 0 clamp(40px, 6vw, 72px);
  display: flex;
  flex-direction: column;
  gap: 32px;
}
.hero h1 {
  margin: 0;
  font: 700 clamp(88px, 17vw, 220px)/0.85 var(--sans);
  letter-spacing: -0.06em;
}
.hero .accent { color: var(--accent); }
.hero-links { display: flex; gap: 24px; flex-wrap: wrap; font-size: 14px; }

/* ---------- 12-column section pattern ---------- */
.grid-section {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  column-gap: 20px;
  border-top: var(--rule);
  padding-top: 20px;
}
.section-label {
  grid-column: span 3;
  min-width: 160px;
  padding-bottom: 16px;
  font-weight: 500;
  font-size: 12px;
}
.section-content {
  grid-column: span 9;
  display: flex;
  flex-direction: column;
  min-width: min(100%, 280px);
}
.section-built { margin-bottom: 56px; }
.section-writing { margin-bottom: 72px; }

@media (max-width: 720px) {
  .grid-section > * { grid-column: 1 / -1 !important; }
}

/* ---------- Projects (accordion) ---------- */
.project { border-bottom: var(--rule); }
.project > summary { list-style: none; }
.project > summary::-webkit-details-marker { display: none; }
.project-head {
  cursor: pointer;
  display: grid;
  grid-template-columns: 40px 1fr auto;
  gap: 6px 16px;
  align-items: baseline;
  padding: 20px 8px;
}
.project-head:hover { background: var(--accent); }
.project-head:focus-visible { outline: 2px solid var(--ink); outline-offset: -2px; }
.project-num { font-size: 12px; }
.project-name {
  font: 500 clamp(20px, 2.2vw, 26px)/1.2 var(--sans);
  letter-spacing: -0.02em;
}
.project-sign { font-size: 18px; }
.project-sign::before { content: "+"; }
.project[open] .project-sign::before { content: "\2212"; }
.project-meta { font-size: 12px; color: var(--muted); }

.label {
  font: 500 11px var(--mono);
  letter-spacing: 0.08em;
}
.project-body {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 220px), 1fr));
  gap: 24px 32px;
  padding: 4px 8px 32px 64px;
}
.project-col { display: flex; flex-direction: column; gap: 8px; }
.project-col p { margin: 0; font: 400 15px/1.6 var(--sans); text-wrap: pretty; }
.project-col p.result { font-weight: 500; }
.project-col p.result span { background: var(--accent); padding: 0 3px; }

.project-papers {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 0 8px 32px 64px;
}
.paper {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 4px 24px;
  padding: 12px 0;
  border-top: 1px solid var(--hairline);
}
.paper-title { font: 400 16px/1.4 var(--sans); }
.paper-year { font-size: 12px; }
.paper-venue { font-size: 12px; color: var(--muted); }

@media (max-width: 720px) {
  .project-body, .project-papers { padding-left: 8px; }
}

/* ---------- Writing list ---------- */
.post-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 24px;
  align-items: baseline;
  padding: 14px 8px;
  border-bottom: 1px solid var(--hairline);
}
.post-row-title { font: 400 17px/1.35 var(--sans); }
.post-row-date { font-size: 12px; }

/* ---------- Footer ---------- */
.site-footer {
  border-top: var(--rule);
  padding-top: 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 16px 24px;
  justify-content: space-between;
  font-size: 12px;
  color: var(--muted);
}
.site-footer a { color: var(--muted); }
.site-footer a:hover { color: var(--ink); }
.footer-links { display: flex; gap: 20px; flex-wrap: wrap; }

/* ---------- Post page ---------- */
.post-title-block {
  padding: clamp(40px, 7vw, 80px) 0 clamp(32px, 5vw, 56px);
  display: flex;
  flex-direction: column;
  gap: 24px;
}
.post-title-block .back { align-self: flex-start; font-size: 12px; color: var(--muted); }
.post-title {
  margin: 0;
  font: 700 clamp(36px, 5.6vw, 72px)/1.05 var(--sans);
  letter-spacing: -0.04em;
  max-width: 1000px;
  text-wrap: pretty;
}

.post-aside {
  grid-column: span 3;
  min-width: 180px;
  display: flex;
  flex-direction: column;
  gap: 24px;
  padding-bottom: 32px;
  font-size: 12px;
  line-height: 1.7;
  align-self: start;
}
@media (min-width: 721px) {
  .post-aside { position: sticky; top: 24px; }
}
.post-aside .b { font-weight: 500; }
.post-aside .gap { margin-top: 10px; }
.post-dates { display: flex; flex-direction: column; }
.toc { display: flex; flex-direction: column; align-items: flex-start; gap: 4px; }
.toc .b { margin-bottom: 2px; }
.toc a { color: var(--muted); }
.toc a:hover { color: var(--ink); }

/* Article typography */
.prose {
  grid-column: span 9;
  min-width: min(100%, 280px);
  max-width: 680px;
  font: 400 17px/1.9 var(--sans);
  color: var(--text);
  display: flex;
  flex-direction: column;
  gap: 18px;
  overflow-wrap: anywhere;
}
.prose > * { margin: 0; }
.prose h2 {
  margin: 24px 0 -4px;
  font: 700 26px/1.3 var(--sans);
  letter-spacing: -0.02em;
  color: var(--ink);
}
.prose > h2:first-child { margin-top: 0; }
.prose h2.sec { display: flex; gap: 14px; align-items: baseline; }
.prose .sec-num { font: 400 12px var(--mono); flex: none; }
.prose h3 { font: 700 18px/1.5 var(--sans); color: var(--ink); }
.prose h4, .prose h5, .prose h6 { font: 700 17px/1.5 var(--sans); color: var(--ink); }
.prose .headerlink { display: none; }
.prose a { background: var(--code-bg); padding: 0 2px; }
.prose a:hover { background: var(--accent); }
.prose blockquote {
  margin: 8px 0;
  padding: 4px 0 4px 20px;
  border-left: 6px solid var(--accent);
  font: 500 21px/1.6 var(--sans);
  letter-spacing: -0.01em;
}
.prose blockquote p { margin: 0; }
.prose ul, .prose ol {
  padding-left: 22px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.prose li > p { margin: 0; }
.prose img {
  display: block;
  max-width: 100%;
  max-height: 520px;
  object-fit: contain;
  border: var(--rule);
  background: #fff;
}
.prose figure:not(.highlight) { display: flex; flex-direction: column; gap: 8px; margin: 8px 0; }
.prose figcaption, .prose .img-caption { font: 400 12px var(--mono); color: var(--muted); }
.prose hr { border: 0; border-top: 1px solid var(--hairline); width: 100%; }
.prose table:not(.highlight table) { border-collapse: collapse; font-size: 15px; }
.prose th, .prose td { border-bottom: 1px solid var(--hairline); padding: 6px 12px 6px 0; text-align: left; }

/* Inline code */
.prose code {
  font: 400 14px var(--mono);
  background: var(--code-bg);
  padding: 2px 6px;
}

/* Code blocks (Hexo highlight output and plain pre) */
.prose figure.highlight,
.prose pre {
  margin: 0;
  background: var(--ink);
  color: var(--bg);
  overflow-x: auto;
}
.prose figure.highlight { padding: 20px 22px; }
.prose figure.highlight pre { padding: 0; }
.prose pre { padding: 20px 22px; font: 400 14px/1.7 var(--mono); }
.prose pre code, .prose figure.highlight code {
  background: none;
  padding: 0;
  color: inherit;
  font: 400 14px/1.7 var(--mono);
}
.prose figure.highlight table { border-collapse: collapse; margin: 0; }
.prose figure.highlight td { padding: 0; border: 0; }
.prose figure.highlight .gutter { display: none; }
.prose figure.highlight figcaption { color: var(--muted); margin-bottom: 8px; }
.prose figure.highlight .line { display: inline; }
/* Accent tokens: keywords, built-ins, prompts */
.prose .keyword, .prose .built_in, .prose .selector-tag, .prose .meta,
.prose .hljs-keyword, .prose .hljs-built_in, .prose .hljs-meta { color: var(--accent); }
.prose .comment, .prose .hljs-comment { color: var(--muted); }

/* Prev / next */
.post-nav {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr));
  border-top: var(--rule);
  margin-top: 72px;
}
.post-nav a { display: flex; flex-direction: column; gap: 6px; padding: 20px 8px; }
.post-nav a .muted { font-size: 12px; }
.post-nav a.right { text-align: right; }
.post-nav-title { font: 500 20px/1.3 var(--sans); letter-spacing: -0.01em; }

/* Page (e.g. about) without post nav still needs space before the footer */
.post-body { margin-bottom: 72px; }
.post-body + .post-nav { margin-top: 0; }