/* ============================================
   Academic Portfolio — Single-page, three-column.
   White bg, black text, UMich dark-blue accent.
   ============================================ */

:root {
  --bg: #ffffff;
  --ink: #111111;
  --ink-soft: #333333;
  --ink-muted: #7a7a7a;
  --line-soft: #e6e6e6;

  /* Cornflower blue accent */
  --accent: #6495ED;            /* cornflower blue — links, highlights */
  --accent-strong: #4a7fd1;     /* darker hover */
  --accent-bg: #eef3fd;         /* soft tinted background */
  --accent-bg-border: #c8d6f5;  /* soft border */
  --accent-tint-rgb: 100, 149, 237; /* for rgba() overlays */

  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue",
          Helvetica, Arial, "PingFang SC", "Hiragino Sans GB",
          "Microsoft YaHei", sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  font-size: 17px;            /* GLOBAL font size — tune this one value
                                 (14.5 was the previous small default; raise
                                 to 18–20 for even larger text) */
}

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.45;           /* reduced from 1.65 */
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Tabular numerals — aligns dates / years / venue numbers vertically */
.news-date,
.pub-venue,
.pub-badge,
.site-footer time { font-variant-numeric: tabular-nums; }

a {
  color: var(--accent);
  text-decoration: none;
  background-image: linear-gradient(var(--accent-strong), var(--accent-strong));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0 1px;
  padding-bottom: 1px;
  transition: background-size 0.28s cubic-bezier(0.65, 0, 0.35, 1),
              color 0.18s ease;
}
a:hover {
  color: var(--accent-strong);
  background-size: 100% 1px;
  text-decoration: none;
}

/* Links that own their interaction (sidebar, pub chips, hover overlay, etc.)
   opt out of the gradient underline so they stay visually distinct. */
.id-links a,
.pub-link-overlay,
.pub-links a,
.site-footer a,
.news-header a { background-image: none; padding-bottom: 0; }

img { max-width: 100%; display: block; }

/* ============================================
   Layout — three columns with outer breathing room
   ============================================ */
.page {
  max-width: 1400px;
  margin: 0 auto;
  padding: 2.5rem 1rem 0.75rem;   /* moderate bottom padding above footer */
  display: grid;
  /* middle column is now capped at 720px so there's no dead space
     between the bio and the Recent Highlights column */
  grid-template-columns: 200px minmax(0, 720px) 260px;
  column-gap: 2rem;            /* tighter left-to-main spacing */
  row-gap: 2rem;
  align-items: start;
  justify-content: center;     /* center the three columns within the page */
}

.sidebar-left,
.sidebar-right {
  position: sticky;
  top: 2.5rem;
  align-self: start;
}

.sidebar-left  { padding-left: 0.5rem; }
.sidebar-right { padding-right: 0.5rem; }

.sidebar-right {
  padding-right: 0.5rem;
  /* No max-height / overflow — let the column grow with its content. */
}

/* ============================================
   Left sidebar — identity
   ============================================ */
.id-name {
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  line-height: 1.25;
  color: var(--ink);
  margin-bottom: 0.5rem;
}

.id-email {
  display: inline-block;      /* shrink to text width so hover underline
                                 doesn't stretch across the sidebar */
  font-size: 0.75rem;
  color: var(--accent);
  margin-bottom: 0.85rem;
  word-break: break-all;
}

/* Chinese name — thin, elegant serif; tight letter-spacing */
.zh-name {
  display: block;
  margin-top: -0.15rem;
  margin-bottom: 0.85rem;
  color: var(--ink);
  font-family: "Noto Serif SC", "Source Han Serif SC", "Songti SC",
               "STSong", "Microsoft YaHei", serif;
  font-weight: 300;
  font-size: 1.05rem;
  letter-spacing: -0.06em;
  line-height: 1.2;
}

.id-photo {
  width: 100%;
  max-width: 180px;      /* 1.2× the previous 150px */
  aspect-ratio: 16 / 10;
  background: #f0f0f0;
  overflow: hidden;
  border-radius: 2px;
  margin-bottom: 1.15rem;
}
.id-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 62% center; /* bias right so the face is centered */
  display: block;
}

.id-links {
  list-style: none;
  font-size: 0.8rem;
  line-height: 1.75;
}
.id-links li a { color: var(--ink); }
.id-links li a:hover { color: var(--accent); text-decoration: none; }
.id-links .arrow { color: var(--ink-muted); margin-left: 0.15em; }

/* ============================================
   Main content
   ============================================ */
.main { max-width: 720px; }

.highlight-box {
  background: var(--accent-bg);
  border: 1px solid var(--accent-bg-border);
  border-radius: 3px;
  padding: 0.8rem 1rem;
  margin-bottom: 1.5rem;
  font-size: 0.85rem;
  line-height: 1.45;
}
.highlight-box strong {
  display: block;
  font-size: 0.88rem;
  margin-bottom: 0.3rem;
  color: var(--ink);
}

.bio-text p {
  font-size: 0.85rem;
  line-height: 1.55;
  color: var(--ink);
  margin-bottom: 0.85rem;
}
.bio-text strong { font-weight: 600; }

.research-interests {
  font-style: italic;
  color: var(--ink-soft);
  font-size: 0.85rem;
  margin-top: 0.85rem;
}

.section-header {
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink);
  margin: 2.6rem 0 0.9rem;   /* breathing room above section titles */
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--line-soft);
}

/* ============================================
   Publications
   ============================================ */
.pub-item {
  display: grid;
  grid-template-columns: 170px 1fr;
  gap: 1.15rem;
  margin-bottom: 1.9rem;
  align-items: start;
}
.pub-item:last-child,
.news-item:last-child { margin-bottom: 0.5rem; }

.pub-thumb {
  position: relative;
  background: transparent;
  border: none;
  overflow: hidden;
  border-radius: 2px;
  cursor: zoom-in;       /* signals click-to-enlarge */
}
.pub-thumb:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
.pub-thumb img {
  width: 100%;
  height: auto;                 /* height follows each image's natural aspect ratio */
  display: block;
  /* Just a gentle desaturation — keeps original hues, quiets them down.
     Restores to full saturation on hover. */
  filter: saturate(0.75) brightness(1.03);
  transition: filter 0.4s ease;
}
.pub-item:hover .pub-thumb img { filter: none; }

/* Hover-reveal: no tint over the image — just the centered circular
   chip holding the zoom-in magnifier icon. Purely visual — the click
   handler lives on .pub-thumb (see js/main.js). */
.pub-link-overlay {
  position: absolute;
  inset: 0;                               /* covers the whole thumb */
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  opacity: 0;
  transition: opacity 0.25s ease;
  z-index: 2;
  pointer-events: none;                   /* let clicks pass through to .pub-thumb */
}
.pub-item:hover .pub-link-overlay,
.pub-thumb:focus-visible .pub-link-overlay {
  opacity: 1;
}

/* Circular white chip behind the icon */
.pub-link-overlay::before {
  content: "";
  position: absolute;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
  transition: transform 0.25s ease, background 0.2s ease;
}
.pub-link-overlay:hover::before {
  transform: scale(1.08);
  background: rgba(255, 255, 255, 0.95);
}

.pub-link-overlay svg {
  position: relative;  /* above the ::before chip */
  z-index: 1;
  width: 14px;
  height: 14px;
  stroke: #2c4a7d;     /* darker cornflower tone so icon reads against chip */
  fill: none;
  stroke-width: 1.9;
  stroke-linecap: round;
  stroke-linejoin: round;
  transition: stroke 0.15s ease;
}
.pub-link-overlay:hover svg { stroke: #1f3a66; }

.pub-body h3 {
  font-size: 0.82rem;
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: 0.18rem;
  color: var(--ink);
}
.pub-authors {
  font-size: 0.75rem;
  color: var(--ink);
  margin-bottom: 0.1rem;
  line-height: 1.4;
}
.pub-authors .me {
  text-decoration: underline;
  text-underline-offset: 2px;
  text-decoration-thickness: 1px;
  font-weight: 500;
}
.pub-venue {
  font-size: 0.75rem;
  color: var(--ink-soft);
  margin-bottom: 0.35rem;
}
.pub-badge {
  display: inline-block;
  background: #fff6d5;
  color: #7a5a00;
  font-size: 0.68rem;
  padding: 0.1rem 0.5rem;
  border-radius: 999px;
  margin-left: 0.3rem;
  vertical-align: middle;
  font-weight: 500;
}
.pub-badge.best   { background: #fef1d5; color: #8a5a00; }
.pub-badge.impact { background: #fde1d1; color: #9a4a1a; }

.pub-abstract {
  font-size: 0.70rem;
  color: var(--ink-soft);
  font-style: italic;
  line-height: 1.45;
  margin-bottom: 0.45rem;
}
.pub-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.1rem 0.6rem;
  font-size: 0.78rem;
  color: var(--accent);
}
.pub-links a {
  display: inline-flex;
  align-items: center;
  color: var(--accent);
}
.pub-links a::before {
  content: "·";
  margin-right: 0.4rem;
  color: var(--ink-muted);
}
.pub-links a:first-child::before { content: none; }

/* Small icon before each link's text (abs / bib / doi / pdf / …).
   Injected by js/main.js based on the link's visible text. */
.pub-links a svg {
  width: 12px;
  height: 12px;
  margin-right: 0.3em;
  flex-shrink: 0;
}
/* Ephemeral "copied!" feedback state on the bib link */
.pub-links a.is-copied {
  color: #2f9e44;              /* soft green — signals success */
  font-weight: 500;
}

/* ============================================
   Right sidebar — news
   ============================================ */
.news-header {
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink);
  margin-bottom: 1.15rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--line-soft);
}
.news-item {
  margin-bottom: 1.15rem;
  font-size: 0.72rem;
  line-height: 1.5;
  color: var(--ink);
}
.news-date {
  font-size: 0.6rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-muted);
  margin-bottom: 0.22rem;
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 1100px) {
  .page {
    grid-template-columns: 180px minmax(0, 1fr);
    column-gap: 2rem;
    row-gap: 1.5rem;
    padding: 2rem 3rem 3rem;
  }
  /* Unstick the left sidebar so it doesn't overlap the right sidebar
     when the right column collapses to a full-width row below. */
  .sidebar-left {
    position: static;
  }
  .sidebar-right {
    grid-column: 1 / -1;
    position: static;
    max-height: none;
    overflow-y: visible;
    border-top: 1px solid var(--line-soft);
    margin-top: 2.5rem;
    padding-top: 1.5rem;
  }
}

@media (max-width: 700px) {
  .page {
    grid-template-columns: 1fr;
    padding: 1.5rem 1.25rem 2.5rem;
    gap: 1.5rem;
  }
  .sidebar-left {
    position: static;
    display: grid;
    grid-template-columns: 110px 1fr;
    gap: 1rem;
    align-items: center;
    padding-left: 0;
  }
  .id-name  { margin-bottom: 0.25rem; }
  .id-email { margin-bottom: 0.25rem; }
  .id-photo {
    width: 110px;
    max-width: 110px;
    aspect-ratio: 16 / 10;
    margin-bottom: 0;
    grid-row: 1 / span 3;
  }
  .id-links { grid-column: 2; }
  .sidebar-right {
    margin-top: 1.5rem;
    padding-top: 1.25rem;
    padding-right: 0;
  }
  .section-header { margin-top: 2rem; }
}

/* ============================================
   Narrow screens (phones + small tablets + narrow browser windows) —
   stack publication thumbnail on top of the text
   for a more readable "card"-style layout.
   ============================================ */
@media (max-width: 800px) {
  .pub-item {
    grid-template-columns: 1fr;   /* single column: thumb on top, body below */
    gap: 0.8rem;
    margin-bottom: 2.2rem;
  }
  .pub-thumb {
    max-width: 170px;   /* keep same width as desktop; just stacks above text */
  }
  /* Typography (h3, authors, venue, links, badge) inherits from the base
     desktop rules — no font-size overrides here on purpose. */
}

/* Legacy placeholder tint classes — no-op now that images fill the box. */
.tint-1,
.tint-2,
.tint-3,
.tint-4 { background: transparent; }

/* ============================================
   Site footer — tiny meta line
   ============================================ */
.site-footer {
  margin: 0.35rem 0 0;
  padding: 0.65rem 1rem 0.85rem;
  border-top: 1px solid var(--line-soft);
  text-align: center;
  color: var(--ink-muted);
  font-size: 0.62rem;
  letter-spacing: 0.05em;
  line-height: 1.3;
}
.site-footer p { margin: 0; }
.site-footer .dot { margin: 0 0.45em; opacity: 0.6; }
.site-footer a { color: var(--ink-muted); }
.site-footer a:hover { color: var(--accent-strong); }

@media (max-width: 900px) {
  .site-footer { padding: 0.65rem 1rem 0.85rem; }
}

/* ============================================
   Lightbox — full-screen figure preview
   ============================================ */
.lightbox {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.88);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2.5rem;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.25s ease, visibility 0.25s ease;
  cursor: zoom-out;
}
.lightbox.open {
  opacity: 1;
  visibility: visible;
}
.lightbox img {
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: contain;
  background: #fff;
  border-radius: 4px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
  cursor: default;
  transform: scale(0.96);
  transition: transform 0.25s ease;
}
.lightbox.open img {
  transform: scale(1);
}
.lightbox-close {
  position: absolute;
  top: 1.25rem;
  right: 1.25rem;
  width: 40px;
  height: 40px;
  border: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.15);
  color: #fff;
  font-size: 1.5rem;
  line-height: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s ease, transform 0.2s ease;
  padding: 0;
}
.lightbox-close:hover {
  background: rgba(255, 255, 255, 0.3);
  transform: scale(1.05);
}
.lightbox-close:focus-visible {
  outline: 2px solid #fff;
  outline-offset: 2px;
}
@media (max-width: 700px) {
  .lightbox { padding: 1rem; }
  .lightbox-close { top: 0.75rem; right: 0.75rem; }
}

/* ============================================
   Back-to-top floating button — appears after scrolling.
   ============================================ */
#back-to-top {
  position: fixed;
  bottom: 1.25rem;
  right: 1.25rem;
  width: 38px;
  height: 38px;
  border: 1px solid var(--line-soft);
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  color: var(--ink-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  opacity: 0;
  visibility: hidden;
  transform: translateY(6px);
  transition: opacity 0.25s ease, visibility 0.25s ease,
              transform 0.25s ease, color 0.18s ease,
              border-color 0.18s ease;
  z-index: 900;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}
#back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
#back-to-top:hover {
  color: var(--accent);
  border-color: var(--accent);
}
#back-to-top:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
#back-to-top svg {
  width: 16px;
  height: 16px;
}
@media (max-width: 700px) {
  #back-to-top {
    bottom: 1rem;
    right: 1rem;
    width: 36px;
    height: 36px;
  }
}