:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --text: #1c1e21;
  --muted: #667085;
  --border: #e4e7ec;
  --accent: #2563eb;
  --accent-weak: #eff4ff;
  --highlight-bg: #fff9e6;
  --highlight-border: #f2d98a;
  --radius: 12px;
  --maxw: 900px;
}
[data-theme="dark"] {
  --bg: #0f1115;
  --surface: #171a21;
  --text: #e6e8eb;
  --muted: #9aa4b2;
  --border: #262b36;
  --accent: #6ea8fe;
  --accent-weak: #1c2536;
  --highlight-bg: #241f10;
  --highlight-border: #4d421f;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Top bar */
.topbar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; padding: .75rem 1.25rem;
  background: var(--surface); border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 10;
}
.brand a { font-weight: 700; font-size: 1.15rem; color: var(--text); }
.mainnav { display: flex; align-items: center; gap: 1rem; }
.mainnav a { color: var(--muted); font-weight: 500; }
.mainnav .search input {
  padding: .4rem .6rem; border: 1px solid var(--border);
  border-radius: 8px; background: var(--bg); color: var(--text);
}
#theme-toggle { background: none; border: none; font-size: 1.1rem; cursor: pointer; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 1.5rem 1.25rem 4rem; }

/* Day bar */
.daybar {
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: .75rem; margin-bottom: 1rem;
}
.daynav { display: flex; align-items: center; gap: .6rem; }
.day-title { font-size: 1.6rem; margin: 0; }
.nav-btn { padding: .3rem .6rem; border: 1px solid var(--border); border-radius: 8px; color: var(--muted); }
.nav-btn.disabled { opacity: .4; }
.nav-btn.today { background: var(--accent-weak); color: var(--accent); }
.dayactions { display: flex; align-items: center; gap: .6rem; }
.dayactions select, .dayactions button, .search-page button {
  padding: .4rem .7rem; border: 1px solid var(--border); border-radius: 8px;
  background: var(--surface); color: var(--text); cursor: pointer;
}
#refresh-btn { background: var(--accent); color: #fff; border-color: var(--accent); font-weight: 600; }
.refresh-status { color: var(--muted); font-size: .85rem; }

/* Overview strip */
.overview {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: .7rem 1rem; margin-bottom: 1.5rem;
  font-size: .95rem; color: var(--muted);
}
.overview strong { color: var(--text); }
.genat { float: right; font-size: .8rem; }

/* WeChat login-expiry alert */
.wechat-alert {
  background: #fdeBeB; background: #fdecec; border: 1px solid #f2b8b8;
  color: #9b2c2c; border-radius: var(--radius); padding: .7rem 1rem;
  margin-bottom: 1rem; font-size: .95rem;
}
.wechat-alert a { color: #9b2c2c; font-weight: 700; text-decoration: underline; }
[data-theme="dark"] .wechat-alert { background: #2a1414; border-color: #5a2626; color: #f0a0a0; }
[data-theme="dark"] .wechat-alert a { color: #f0a0a0; }

/* Category tabs */.tabbar {
  display: flex; gap: .35rem; flex-wrap: wrap;
  border-bottom: 2px solid var(--border); margin: 0 0 1.25rem;
}
.tabbar .tab {
  appearance: none; background: none; border: none; cursor: pointer;
  font: inherit; font-weight: 600; color: var(--muted);
  padding: .55rem .9rem; border-bottom: 3px solid transparent;
  margin-bottom: -2px; border-radius: 8px 8px 0 0;
}
.tabbar .tab:hover { color: var(--text); background: var(--accent-weak); }
.tabbar .tab.active { color: var(--accent); border-bottom-color: var(--accent); }
.tabbar .tab .count {
  font-size: .72rem; background: var(--accent-weak); color: var(--accent);
  border-radius: 999px; padding: .05rem .45rem; margin-left: .3rem;
}
.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* Topic sections */
.topic-section { margin-bottom: 2.25rem; }
.topic-head {
  font-size: 1.25rem; border-bottom: 2px solid var(--border);
  padding-bottom: .35rem; display: flex; align-items: center; gap: .5rem;
}
.topic-head .count {
  font-size: .8rem; background: var(--accent-weak); color: var(--accent);
  border-radius: 999px; padding: .05rem .5rem;
}
.highlights {
  background: var(--highlight-bg); border: 1px solid var(--highlight-border);
  border-radius: var(--radius); padding: .5rem 1rem; margin: .75rem 0 1rem;
}
.highlights-label {
  font-size: .72rem; text-transform: uppercase; letter-spacing: .06em;
  color: var(--muted); font-weight: 700; margin-bottom: .2rem;
}
.highlights ul { margin: .3rem 0; padding-left: 1.2rem; }

/* Cards */
.cards { display: flex; flex-direction: column; gap: 1rem; }
.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1rem 1.15rem;
}
.card-layout, .card-body { min-width: 0; }
.card-has-image .card-layout {
  display: grid; grid-template-columns: minmax(150px, 200px) minmax(0, 1fr);
  gap: 1rem; align-items: start;
}
.card-thumbnail {
  display: block; overflow: hidden; border: 1px solid var(--border);
  border-radius: 9px; background: var(--bg); aspect-ratio: 16 / 9;
}
.card-thumbnail img {
  display: block; width: 100%; height: 100%; object-fit: cover;
}
.card-title { margin: 0 0 .4rem; font-size: 1.1rem; line-height: 1.35; }
.merged-badge {
  font-size: .72rem; background: var(--accent-weak); color: var(--accent);
  border-radius: 999px; padding: .05rem .5rem; margin-left: .4rem; white-space: nowrap;
}
.card-meta { display: flex; flex-wrap: wrap; gap: .4rem; align-items: center; margin-bottom: .5rem; }
.card-summary p:first-child { margin-top: 0; }
.card-summary { font-size: .96rem; }
.card-foot { margin-top: .5rem; }
.details { font-size: .85rem; font-weight: 600; }
.authors, .date, .ident { font-size: .8rem; color: var(--muted); }

/* Source pills */
.pill {
  display: inline-block; font-size: .72rem; font-weight: 600;
  padding: .12rem .5rem; border-radius: 999px; border: 1px solid var(--border);
  color: var(--muted); background: var(--bg);
}
.pill-arxiv   { color: #b31b1b; border-color: #f3c6c6; background: #fdeeee; }
.pill-journal { color: #0b7285; border-color: #b3e0e5; background: #e7fafc; }
.pill-blog    { color: #2b6a2f; border-color: #bfe3c0; background: #eefaef; }
.pill-wechat  { color: #1a7d3c; border-color: #b7e5c4; background: #ecfbf0; }
.pill-twitter { color: #1d6fb8; border-color: #bcd9f2; background: #eaf4fd; }
.pill-topic   { color: var(--accent); border-color: var(--accent); background: var(--accent-weak); }
.pill-cat     { color: #6b3fa0; border-color: #d3bdf0; background: #f3ecfb; }
[data-theme="dark"] .pill-arxiv,
[data-theme="dark"] .pill-journal,
[data-theme="dark"] .pill-blog,
[data-theme="dark"] .pill-wechat,
[data-theme="dark"] .pill-twitter { background: transparent; }

/* Detail pages */
.detail h1 { font-size: 1.5rem; line-height: 1.3; }
.back { display: inline-block; margin-bottom: .75rem; color: var(--muted); font-size: .9rem; }
.detail-image {
  margin: 1rem 0 1.25rem; max-width: 780px; overflow: hidden;
  border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--surface);
}
.detail-image img {
  display: block; width: 100%; aspect-ratio: 16 / 9;
  object-fit: contain; background: var(--bg);
}
.member {
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: .8rem 1rem; margin-bottom: 1rem; background: var(--surface);
}
.member h3 { margin: 0 0 .3rem; font-size: 1rem; }

/* Archive + search */
.archive { width: 100%; border-collapse: collapse; background: var(--surface); border-radius: var(--radius); overflow: hidden; }
.archive th, .archive td { text-align: left; padding: .55rem .8rem; border-bottom: 1px solid var(--border); }
.archive th { color: var(--muted); font-size: .8rem; text-transform: uppercase; letter-spacing: .04em; }
.search-page { display: flex; gap: .5rem; margin-bottom: 1rem; }
.search-page input { flex: 1; padding: .5rem .7rem; border: 1px solid var(--border); border-radius: 8px; background: var(--surface); color: var(--text); }
.search-meta { color: var(--muted); }

/* Misc */
.empty {
  background: var(--surface); border: 1px dashed var(--border);
  border-radius: var(--radius); padding: 1.5rem; text-align: center; color: var(--muted);
}
.footer {
  max-width: var(--maxw); margin: 0 auto; padding: 1rem 1.25rem 2rem;
  color: var(--muted); font-size: .8rem; display: flex; justify-content: space-between;
}
@media (max-width: 640px) {
  .genat { display: none; }
  .topbar { flex-direction: column; align-items: flex-start; }
  .card-has-image .card-layout { grid-template-columns: minmax(0, 1fr); }
  .card-thumbnail { width: 100%; }
}