/* Modern, minimal stylesheet for Yiping Wang's homepage.
   Light/dark themes via CSS variables, system font stack, responsive, no framework.
   The only JS is the tiny theme toggle (see _includes/head.html and footer.html). */

:root {
  /* Light theme (default) */
  --accent: #2f6f8f;
  --accent-strong: #245a74;
  --fg: #222;
  --muted: #666;
  --border: #e2e2e2;
  --bg: #ffffff;
  --bg-soft: #f7f9fa;
  --box: #fffdf3;
  --maxw: 820px;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  color-scheme: light;
}

:root[data-theme="dark"] {
  /* Dark theme: near-black bg, light text, restrained cyan/teal accent */
  --accent: #4fd1c5;
  --accent-strong: #7fe3d8;
  --fg: #e6e6e6;
  --muted: #9aa4ad;
  --border: #2a2f36;
  --bg: #0d0f12;
  --bg-soft: #14181c;
  --box: #14181c;
  color-scheme: dark;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  color: var(--fg);
  background: var(--bg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.6;
  transition: background-color .2s ease, color .2s ease;
}

/* ---- Layout ---- */
.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 8px 20px 64px;
}

/* ---- Top navigation ---- */
.site-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 20px;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
}
.site-nav .brand {
  font-weight: 700;
  font-size: 1.1em;
  margin-right: auto;
  color: var(--fg);
}
.nav-links { display: flex; flex-wrap: wrap; gap: 4px 18px; }
.site-nav a { color: var(--muted); }
.site-nav a:hover { color: var(--accent); }
.site-nav a.active { color: var(--accent); border-bottom: 2px solid var(--accent); }
.theme-toggle {
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
  font-family: var(--mono);
  font-size: 1em;
  line-height: 1;
  color: var(--muted);
}
.theme-toggle:hover { color: var(--accent); }

/* ---- Typography ---- */
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

h1 { font-size: 1.7em; line-height: 1.2; margin: 0.4em 0 0.3em; }
h2 {
  font-size: 1.25em;
  margin: 1.8em 0 0.6em;
  padding-bottom: 0.2em;
  border-bottom: 1px solid var(--border);
}
/* Tech accent: a small accent bar before each section heading */
h2::before {
  content: "";
  display: inline-block;
  width: 3px;
  height: 0.85em;
  margin-right: 8px;
  vertical-align: -1px;
  background: var(--accent);
  border-radius: 2px;
}
p { margin: 0.6em 0; }

.note { color: var(--muted); font-size: 0.9em; }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* ---- Profile card ---- */
.profile {
  display: flex;
  gap: 24px;
  align-items: center;
  margin-top: 12px;
}
.profile .avatar {
  width: 190px;
  border-radius: 8px;
  border: 1px solid var(--border);   /* subtle framing */
  flex-shrink: 0;
}
.profile-meta h1 { margin-top: 0; }
.profile-meta .contact a { color: var(--accent); font-weight: 500; }

/* ---- News list ---- */
ul.news, ul.thoughts { padding-left: 1.2em; }
ul.news li, ul.thoughts li { margin: 0.35em 0; }
ul.news li b { font-family: var(--mono); }   /* monospace date labels */
/* Tech accent: accent-colored bullets for content lists (home / fun / misc) */
.container ul li::marker { color: var(--accent); }

/* ---- Publication & project cards ---- */
.pub-item {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
  margin: 0 0 16px;
}
.pub-item.boxed {                        /* emphasize selected papers */
  background: var(--box);
  border-left: 3px solid var(--accent);  /* accent bar for extra contrast */
}
.pub-title { font-size: 1.02em; }
.pub-authors { margin: 4px 0; }
.pub-note, .pub-venue { margin: 2px 0; }
.pub-tldr { color: var(--muted); margin: 4px 0; }
.venue {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.8em;
  color: var(--accent-strong);
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 8px;
}
/* Link pills (replace raw [Arxiv] text) */
.links { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 8px; }
.links a {
  display: inline-block;
  font-size: 0.85em;
  padding: 2px 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--accent);
  white-space: nowrap;
}
.links a:hover { border-color: var(--accent); background: var(--bg-soft); text-decoration: none; }
/* Live GitHub star count (fetched by JS), themed to match — no external badge */
.ghstars { font-family: var(--mono); color: var(--muted); white-space: nowrap; }
.ghstars .star { color: var(--accent); }

/* Collapsible BibTeX (native <details>, no JS) */
.bib { margin-top: 8px; }
.bib > summary {
  cursor: pointer;
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.8em;
  color: var(--muted);
  list-style: none;
  user-select: none;
}
.bib > summary::-webkit-details-marker { display: none; }
.bib > summary::before { content: "▸ "; color: var(--accent); }
.bib[open] > summary::before { content: "▾ "; }
.bib > summary:hover { color: var(--accent); }
.bib pre {
  margin: 6px 0 0;
  padding: 10px 12px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: var(--mono);
  font-size: 0.78em;
  line-height: 1.45;
  color: var(--fg);
  overflow-x: auto;
}

/* ---- Structured entries (experience / honors / dated thoughts) ---- */
ul.entries li { margin: 0 0 12px; }
.entry-date { font-family: var(--mono); font-size: 0.82em; color: var(--accent-strong); }
.entry-sub { color: var(--muted); }

/* ---- Cubi gallery ---- */
.gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 10px;
  margin: 12px 0;
}
.gallery img {
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  border-radius: 8px;
}

/* ---- Footer ---- */
.site-footer {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 20px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.85em;
}

/* ---- Images never overflow ---- */
img { max-width: 100%; height: auto; border: 0; }

/* ---- Responsive: stack on narrow screens ---- */
@media (max-width: 620px) {
  body { font-size: 16px; }
  .profile { flex-direction: column; text-align: center; gap: 14px; }
  .profile .avatar { width: 200px; }
  .site-nav .brand { margin-right: 0; width: 100%; }
}