/* 深夜自习室 — night-ink & candlelight design tokens */
:root {
  --paper: #fdfdfb;
  --paper-soft: #f6f7f9;
  --ink: #1d2433;
  --ink-2: #5c6577;
  --ink-3: #99a1b3;
  --line: #e9ebef;
  --line-soft: #f1f2f5;
  --night: #3a55c4;          /* 夜墨蓝 primary accent */
  --night-soft: #eef1fb;
  --candle: #b4690e;         /* 烛光琥珀 — reserved for 追记 */
  --candle-soft: #fdf6ec;
  --candle-line: #f0ddc0;
  --serif: "Noto Serif SC", "Songti SC", STSong, "SimSun", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
          "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --mono: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.75;
  letter-spacing: 0.01em;
}
a { color: inherit; text-decoration: none; }
::selection { background: var(--night-soft); }

.wrap { max-width: 820px; margin: 0 auto; padding: 0 28px; }

/* ---------- masthead ---------- */
.masthead { padding: 72px 0 0; }
.masthead .moon {
  font-size: 15px; color: var(--night); letter-spacing: 0.4em;
  font-family: var(--mono);
}
.masthead h1 {
  font-family: var(--serif);
  font-size: 40px; font-weight: 700; letter-spacing: 0.06em;
  margin: 10px 0 6px;
}
.masthead h1 a:hover { color: var(--night); }
.masthead .tagline { color: var(--ink-2); font-size: 15px; }
.masthead .meta {
  margin-top: 26px; padding-bottom: 18px; border-bottom: 1px solid var(--line);
  color: var(--ink-3); font-size: 12.5px; font-family: var(--mono);
  display: flex; gap: 18px;
}

/* ---------- tag filter ---------- */
.tagbar { display: flex; flex-wrap: wrap; gap: 8px; padding: 20px 0 6px; }
.tagbar .chip {
  font-size: 12.5px; color: var(--ink-2);
  border: 1px solid var(--line); border-radius: 100px;
  padding: 3px 13px; cursor: pointer; background: transparent;
  font-family: var(--sans); transition: all .15s ease;
}
.tagbar .chip:hover { border-color: var(--night); color: var(--night); }
.tagbar .chip.on { background: var(--night); border-color: var(--night); color: #fff; }

/* ---------- doc list ---------- */
.month-label {
  font-family: var(--mono); font-size: 12px; color: var(--ink-3);
  letter-spacing: 0.12em; margin: 34px 0 4px;
}
.doc-row {
  display: flex; gap: 26px; padding: 22px 0;
  border-bottom: 1px solid var(--line-soft);
  opacity: 0; animation: rise .5s ease forwards;
}
@keyframes rise { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
.doc-row .when {
  flex: 0 0 64px; text-align: right; font-family: var(--mono);
  padding-top: 3px;
}
.doc-row .when .d { font-size: 13px; color: var(--ink-2); }
.doc-row .when .t { font-size: 12px; color: var(--night); margin-top: 2px; }
.doc-row .when .t::before { content: "☾ "; font-size: 10px; }
.doc-row .body { flex: 1; min-width: 0; }
.doc-row h2 {
  font-family: var(--serif); font-size: 18px; font-weight: 700;
  line-height: 1.5; transition: color .15s ease;
}
.doc-row:hover h2 { color: var(--night); }
.doc-row .summary {
  color: var(--ink-2); font-size: 13.5px; margin-top: 6px;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}
.doc-row .foot { display: flex; align-items: center; gap: 8px; margin-top: 10px; flex-wrap: wrap; }
.tag {
  font-size: 11.5px; color: var(--ink-3);
  background: var(--paper-soft); border-radius: 4px; padding: 1.5px 8px;
}
.badge-update {
  font-size: 11.5px; color: var(--candle);
  background: var(--candle-soft); border: 1px solid var(--candle-line);
  border-radius: 4px; padding: 0.5px 8px;
}
.empty { padding: 60px 0; text-align: center; color: var(--ink-3); font-size: 14px; }

footer {
  margin: 70px 0 50px; padding-top: 20px; border-top: 1px solid var(--line);
  color: var(--ink-3); font-size: 12px; font-family: var(--mono);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px;
}

/* ---------- reader page ---------- */
.topbar {
  position: sticky; top: 0; z-index: 10;
  background: rgba(253,253,251,.92); backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.topbar .in {
  max-width: 820px; margin: 0 auto; padding: 13px 28px;
  display: flex; justify-content: space-between; align-items: center;
}
.topbar .home { font-family: var(--serif); font-weight: 700; font-size: 15px; }
.topbar .home:hover { color: var(--night); }
.topbar .home::before { content: "←"; font-family: var(--mono); margin-right: 10px; color: var(--ink-3); }
.topbar .clock { font-family: var(--mono); font-size: 12px; color: var(--ink-3); }

.doc-head { padding: 58px 0 0; }
.doc-head h1 {
  font-family: var(--serif); font-size: 30px; font-weight: 700;
  line-height: 1.5; letter-spacing: 0.02em;
}
.doc-head .meta {
  display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
  margin: 18px 0 0; font-size: 12.5px; color: var(--ink-3); font-family: var(--mono);
}
.doc-head .meta .written { color: var(--night); }
.doc-head .meta .written::before { content: "☾ "; }

/* 追记 timeline box */
.updates-box {
  margin: 26px 0 0; border: 1px solid var(--candle-line);
  background: var(--candle-soft); border-radius: 8px; padding: 14px 18px;
}
.updates-box .label {
  font-size: 12px; color: var(--candle); font-weight: 600;
  letter-spacing: 0.1em; margin-bottom: 6px;
}
.updates-box li {
  list-style: none; font-size: 13px; color: var(--ink-2);
  padding: 3px 0; display: flex; gap: 12px;
}
.updates-box li .ud { font-family: var(--mono); color: var(--candle); flex: 0 0 auto; }

/* article body */
article { padding: 34px 0 80px; }
article > * { margin-bottom: 16px; }
article h1, article h2, article h3, article h4 {
  font-family: var(--serif); line-height: 1.5; margin: 34px 0 14px;
}
article h1 { font-size: 24px; }
article h2 { font-size: 21px; padding-bottom: 8px; border-bottom: 1px solid var(--line); }
article h3 { font-size: 17.5px; }
article h2.zhuiji { border-bottom-color: var(--candle-line); color: var(--candle); }
article h2.zhuiji::before { content: "☾ "; font-size: 15px; }
article p { margin-bottom: 16px; }
article li { margin: 5px 0 5px 1.6em; }
article blockquote {
  border-left: 3px solid var(--night); background: var(--night-soft);
  padding: 10px 18px; border-radius: 0 6px 6px 0; color: var(--ink-2);
}
article blockquote p { margin: 4px 0; }
article code {
  font-family: var(--mono); font-size: 13px;
  background: var(--paper-soft); border-radius: 4px; padding: 1.5px 6px;
}
article pre {
  background: var(--paper-soft); border: 1px solid var(--line);
  border-radius: 8px; padding: 16px 18px; overflow-x: auto; line-height: 1.6;
}
article pre code { background: none; padding: 0; font-size: 12.8px; }
article table {
  border-collapse: collapse; width: 100%; font-size: 13.5px; display: block; overflow-x: auto;
}
article th, article td { border: 1px solid var(--line); padding: 8px 13px; text-align: left; }
article th { background: var(--paper-soft); font-weight: 600; white-space: nowrap; }
article hr { border: none; border-top: 1px solid var(--line); margin: 34px 0; }
article img { max-width: 100%; border-radius: 8px; }
article strong { font-weight: 700; }

/* TOC */
.toc {
  position: fixed; top: 110px; right: max(24px, calc(50vw - 410px - 240px));
  width: 200px; max-height: 70vh; overflow-y: auto;
  font-size: 12.5px; display: none;
}
@media (min-width: 1280px) { .toc { display: block; } }
.toc .toc-label {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.15em;
  color: var(--ink-3); margin-bottom: 10px;
}
.toc a {
  display: block; color: var(--ink-3); padding: 3.5px 0 3.5px 12px;
  border-left: 2px solid var(--line); line-height: 1.5;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.toc a.lv3 { padding-left: 26px; font-size: 12px; }
.toc a:hover { color: var(--night); }
.toc a.cur { color: var(--night); border-left-color: var(--night); }

@media (max-width: 640px) {
  .wrap { padding: 0 20px; }
  .masthead { padding-top: 48px; }
  .masthead h1 { font-size: 32px; }
  .doc-row { gap: 16px; }
  .doc-row .when { flex-basis: 52px; }
  .doc-head h1 { font-size: 24px; }
}

/* ---------- share ---------- */
.share-btn {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 12.5px; color: var(--night); cursor: pointer;
  border: 1px solid var(--night); border-radius: 100px;
  background: transparent; padding: 3px 14px; font-family: var(--sans);
  transition: all .15s ease;
}
.share-btn:hover { background: var(--night); color: #fff; }
.toast {
  position: fixed; left: 50%; bottom: 44px; transform: translateX(-50%) translateY(20px);
  background: var(--ink); color: #fff; font-size: 13px;
  padding: 9px 20px; border-radius: 8px; opacity: 0;
  transition: all .25s ease; pointer-events: none; z-index: 99;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ---------- topic cards (homepage) ---------- */
.section-label {
  font-family: var(--mono); font-size: 11.5px; color: var(--ink-3);
  letter-spacing: 0.18em; margin: 36px 0 14px;
}
.topic-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 16px;
}
.topic-card {
  display: block; border: 1px solid var(--line); border-radius: 12px;
  padding: 24px 26px 20px; background: #fff;
  transition: all .18s ease; position: relative; overflow: hidden;
  opacity: 0; animation: rise .5s ease forwards;
}
.topic-card::after {
  content: "☾"; position: absolute; right: 18px; top: 14px;
  font-size: 42px; color: var(--night); opacity: .06; font-family: var(--mono);
}
.topic-card:hover {
  border-color: var(--night);
  box-shadow: 0 6px 24px rgba(58, 85, 196, .09);
  transform: translateY(-2px);
}
.topic-card h2 {
  font-family: var(--serif); font-size: 19px; font-weight: 700; line-height: 1.5;
}
.topic-card:hover h2 { color: var(--night); }
.topic-card .desc {
  color: var(--ink-2); font-size: 13px; margin-top: 8px; line-height: 1.7;
  display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden;
}
.topic-card .tc-foot {
  margin-top: 16px; padding-top: 12px; border-top: 1px solid var(--line-soft);
  font-family: var(--mono); font-size: 12px; color: var(--ink-3);
  display: flex; justify-content: space-between;
}
.topic-card .tc-foot .n { color: var(--night); }
.all-link {
  display: flex; justify-content: space-between; align-items: center;
  margin-top: 16px; padding: 16px 26px;
  border: 1px dashed var(--line); border-radius: 12px;
  color: var(--ink-2); font-size: 14px; transition: all .15s ease;
}
.all-link:hover { border-color: var(--night); color: var(--night); }
.all-link .arrow { font-family: var(--mono); }

/* topic page header */
.topic-head { padding: 56px 0 4px; }
.topic-head .crumb {
  font-family: var(--mono); font-size: 12.5px; color: var(--ink-3);
}
.topic-head .crumb a:hover { color: var(--night); }
.topic-head h1 {
  font-family: var(--serif); font-size: 30px; font-weight: 700; margin: 14px 0 8px;
}
.topic-head .desc { color: var(--ink-2); font-size: 14px; max-width: 640px; }
.topic-head .meta {
  margin-top: 20px; padding-bottom: 16px; border-bottom: 1px solid var(--line);
  color: var(--ink-3); font-size: 12.5px; font-family: var(--mono);
}

/* ---------- thinking-stage chain (topic page) ---------- */
.stage-group { margin-top: 30px; }
.stage-head { display: flex; align-items: center; gap: 12px; }
.stage-num {
  width: 26px; height: 26px; border-radius: 50%; flex: 0 0 26px;
  background: var(--night); color: #fff;
  font-family: var(--mono); font-size: 12.5px;
  display: flex; align-items: center; justify-content: center;
}
.stage-name {
  font-family: var(--serif); font-weight: 700; font-size: 16px; letter-spacing: .04em;
}
.stage-count { font-family: var(--mono); font-size: 12px; color: var(--ink-3); }
.stage-group .docs {
  margin-left: 12px; border-left: 1px solid var(--line);
  padding-left: 26px; margin-top: 4px;
}
.stage-group .docs .doc-row:last-child { border-bottom: none; }
.stage-badge {
  font-size: 11.5px; color: var(--night);
  background: var(--night-soft); border-radius: 4px; padding: 1.5px 8px;
}

/* ---------- epistemic status ---------- */
.status-badge { font-size: 11.5px; border-radius: 4px; padding: 1.5px 8px; }
.status-badge.s-guess    { color: var(--candle); border: 1px solid var(--candle-line); background: var(--candle-soft); }
.status-badge.s-argued   { color: var(--night); border: 1px solid #ccd6f3; background: var(--night-soft); }
.status-badge.s-verified { color: #fff; background: #2e7d4f; border: 1px solid #2e7d4f; }

.epistemic {
  margin: 26px 0 0; border: 1px solid var(--line); border-radius: 10px;
  font-size: 13px; overflow: hidden;
}
.epistemic .row { display: flex; border-bottom: 1px solid var(--line-soft); }
.epistemic .row:last-child { border-bottom: none; }
.epistemic .k {
  flex: 0 0 92px; padding: 10px 16px; color: var(--ink-3);
  background: var(--paper-soft); font-size: 12.5px;
}
.epistemic .v { flex: 1; padding: 10px 16px; color: var(--ink-2); line-height: 1.7; }
.epistemic .v .next-item { display: block; }
.epistemic .v .next-item::before { content: "→ "; color: var(--night); font-family: var(--mono); }

/* ---------- overview block ---------- */
.overview-card {
  display: block; margin-top: 24px;
  border: 1px solid #ccd6f3; background: var(--night-soft);
  border-radius: 12px; padding: 20px 24px;
  transition: all .18s ease;
}
.overview-card:hover { border-color: var(--night); box-shadow: 0 4px 18px rgba(58,85,196,.10); }
.overview-card .ov-label {
  font-family: var(--mono); font-size: 11.5px; color: var(--night);
  letter-spacing: 0.18em; margin-bottom: 6px;
}
.overview-card h2 {
  font-family: var(--serif); font-size: 17px; font-weight: 700; line-height: 1.5;
}
.overview-card:hover h2 { color: var(--night); }
.overview-card .ov-sum { color: var(--ink-2); font-size: 13px; margin-top: 6px; line-height: 1.7; }
.overview-card .ov-foot {
  margin-top: 10px; font-family: var(--mono); font-size: 12px; color: var(--ink-3);
}
.topic-card .ov-hint {
  font-size: 12px; color: var(--night); margin-top: 10px;
}
.topic-card .ov-hint::before { content: "◎ "; }
article h2.fn-sec { border-bottom-color: #ccd6f3; color: var(--night); }
article h2.fn-sec::before { content: "※ "; font-size: 16px; }