/* =============================================
   MEILUN ZHANG — ACADEMIC PERSONAL SITE
   Style: Refined editorial / natural academic
   Fonts: Cormorant Garamond + DM Sans
   ============================================= */

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

:root {
  --ink:       #1a1a18;
  --ink-mid:   #3d3d38;
  --ink-light: #7a7a72;
  --paper:     #f5f3ee;
  --paper-dark:#eceae3;
  --accent:    #2e5c3e;      /* Pacific Northwest forest green */
  --accent-lt: #4a8c63;
  --accent-bg: #e8f0eb;
  --gold:      #b5883a;
  --border:    #d6d2c8;
  --radius:    4px;
  --max-w:     1100px;
  --font-serif: 'Cormorant Garamond', Georgia, serif;
  --font-sans:  'DM Sans', system-ui, sans-serif;
}

html { scroll-behavior: smooth; }

body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
}

/* ── BANNER ─────────────────────────────────── */
.banner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 3rem;
  height: 72px;
  background: var(--paper);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: none;
  border-bottom: 1px solid var(--border);
}

.banner-name {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.name-main {
  font-family: var(--font-sans);
  font-size: 2rem;
  font-weight: 600;
  color: var(--ink);
  letter-spacing: 0.01em;
}

.name-sub {
  font-size: 0.72rem;
  color: var(--ink-light);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-weight: 300;
}

/* ── NAV BUTTONS ─────────────────────────────── */
.banner-nav {
  display: flex;
  gap: 0.4rem;
}

.nav-btn {
  font-family: var(--font-sans);
  font-size: 0.82rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--ink-mid);
  padding: 0.45rem 1.1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.nav-btn:hover,
.nav-btn.active {
  background: var(--accent-bg);
  color: var(--accent);
  border-color: var(--accent);
}

.nav-btn.active {
  background: var(--accent-bg);
  border-color: var(--accent);
}

/* ── HERO IMAGE ──────────────────────────────── */
.hero {
  width: 100%;
  overflow: hidden;
  position: relative;
}

.hero-img-wrap {
  position: relative;
  width: 100%;
  height: clamp(150px, 22vw, 280px);
  overflow: hidden;
}

.hero-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 60%;
  display: block;
  filter: saturate(0.9) brightness(0.95);
  transition: transform 8s ease;
}

.hero-img:hover { transform: scale(1.02); }

.hero-caption {
  position: absolute;
  bottom: 1rem;
  right: 1.4rem;
  font-size: 0.74rem;
  color: rgba(255,255,255,0.75);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  text-shadow: 0 1px 4px rgba(0,0,0,0.5);
}

/* ── CONTAINER ───────────────────────────────── */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 3.5rem 2rem 4rem;
  display: flex;
  flex-direction: column;
  gap: 4rem;
}

/* ── SECTION TITLES ──────────────────────────── */
.section-title {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 400;
  color: var(--accent);
  margin-bottom: 1.5rem;
  padding-bottom: 0.6rem;
  border-bottom: 1.5px solid var(--border);
}

/* ── ABOUT SECTION ───────────────────────────── */
.about-section {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 3.5rem;
  align-items: start;
}

.about-text p {
  color: var(--ink-mid);
  margin-bottom: 1rem;
  font-size: 1.2rem;
}

.about-photo-wrap {
  margin-bottom: 0;
  width: 100%;
  max-width: 300px;
}

.about-photo {
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  border-radius: var(--radius);
  display: block;
  border: 1px solid var(--border);
}

.about-highlights {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.highlight-card {
  background: var(--paper-dark);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 1.1rem 1.2rem;
}


.highlight-icon { font-size: 1.5rem; }

.highlight-card h3 {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0.3rem 0 0.5rem;
}

/* .highlight-card p {
  font-size: 1.1rem;
  color: var(--ink-mid);
  line-height: 1.5;
  margin-bottom: 10px;
} */

.highlight-card p {
  font-size: 1rem;
  color: var(--ink-mid);
  line-height: 1.5;
  margin-bottom: 0;
}

.edu-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
  font-size: 1.1rem;
  gap: 0 8px;
}

.edu-row:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.edu-degree {
  font-weight: 500;
  color: var(--ink);
  width: 2.1rem;
  flex-shrink: 0;
}
.edu-school {
  color: var(--ink-mid);
  flex: 1;
}

.edu-year {
  color: var(--ink-light);
  font-size: 1rem;
  white-space: nowrap;
  width: 100%;
  text-align: right;
  margin-top: 2px;
}

/* ── RECENT HIGHLIGHTS ───────────────────────── */
.highlight-row {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 1.2rem;
}

.highlight-item {
  display: flex;
  gap: 1.2rem;
  align-items: flex-start;
  padding: 0.9rem 1rem;
  background: var(--paper-dark);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.date-tag {
  font-size: 1.1rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  background: var(--accent-bg);
  color: var(--accent);
  padding: 0.2rem 0.55rem;
  border-radius: 2px;
  white-space: nowrap;
  flex-shrink: 0;
  margin-top: 0.15rem;
}

.highlight-item p {
  font-size: 1.2rem;
  color: var(--ink-mid);
}

.btn-link {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--accent);
  text-decoration: none;
  letter-spacing: 0.03em;
  border-bottom: 1px solid var(--accent-lt);
  padding-bottom: 1px;
  transition: color 0.2s;
}
.btn-link:hover { color: var(--accent-lt); }

/* ── NEWS PAGE ───────────────────────────────── */
.news-list { display: flex; flex-direction: column; gap: 1.4rem; }

.news-item {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 1.5rem;
  padding-bottom: 1.4rem;
  border-bottom: 1px solid var(--border);
}

.news-date {
  font-family: var(--font-sans);
  font-size: 0.9rem;
  color: var(--ink-light);
  padding-top: 0.15rem;
}

.news-item h3 {
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 500;
  margin-bottom: 0.3rem;
  color: var(--ink);
}

.news-item p { font-size: 0.88rem; color: var(--ink-mid); }

.news-tag {
  display: inline-block;
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.15rem 0.5rem;
  border-radius: 2px;
  margin-bottom: 0.4rem;
}
.tag-pub   { background: #e0ecff; color: #2255a4; }
.tag-award { background: #fff4d6; color: #8a5c00; }
.tag-talk  { background: #e8f0eb; color: var(--accent); }
.tag-misc  { background: var(--paper-dark); color: var(--ink-light); }

/* ── RESEARCH PAGE ───────────────────────────── */
.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.research-card {
  background: var(--paper-dark);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: box-shadow 0.2s;
}

.research-card:hover { box-shadow: 0 4px 18px rgba(0,0,0,0.08); }

.research-card h3 {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 400;
  color: var(--accent);
  margin-bottom: 0.6rem;
}


/* .research-card p { font-size: 1.2rem; color: var(--ink-mid); } */

.pub-list { display: flex; flex-direction: column; gap: 1.2rem; }

.pub-item {
  padding: 1rem 1.2rem;
  border-left: 3px solid var(--border);
  background: var(--paper-dark);
  border-radius: 0 var(--radius) var(--radius) 0;
  transition: border-color 0.2s;
}

.pub-item:hover { border-left-color: var(--accent); }

.pub-item h4 {
  font-family: var(--font-sans);
  font-size: 1.1rem;
  font-weight: 500;
  margin-bottom: 0.25rem;
}

.pub-item .pub-venue {
  font-size: 1rem;
  color: var(--accent-lt);
  font-style: italic;
}

.pub-item .pub-authors {
  font-size: 1rem;
  color: var(--ink-light);
}

.pub-links { margin-top: 0.5rem; display: flex; gap: 0.6rem; }

.pub-link {
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
  text-decoration: none;
  padding: 0.15rem 0.5rem;
  border: 1px solid var(--accent);
  border-radius: 2px;
  transition: background 0.2s, color 0.2s;
}
.pub-link:hover { background: var(--accent); color: #fff; }

/* ── CONTACT PAGE ────────────────────────────── */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
}

.contact-info p { font-size: 1.2rem; color: var(--ink-mid); margin-bottom: 0.6rem; }

.contact-row {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin-bottom: 0.8rem;
}

.contact-row .icon { font-size: 1.2rem; width: 1.5rem; text-align: center; }

.contact-row a {
  color: var(--accent);
  text-decoration: none;
  font-size: 1.1rem;
}
.contact-row a:hover { text-decoration: underline; }

.contact-row span { font-size: 1rem; color: var(--ink-mid); }


.contact-form { display: flex; flex-direction: column; gap: 1rem; }

.form-group { display: flex; flex-direction: column; gap: 0.3rem; }

.form-group label {
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-light);
}

.form-group input,
.form-group textarea {
  font-family: var(--font-sans);
  font-size: 0.92rem;
  padding: 0.65rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #fff;
  color: var(--ink);
  outline: none;
  transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus { border-color: var(--accent); }

.form-group textarea { resize: vertical; min-height: 130px; }

.submit-btn {
  align-self: flex-start;
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 0.7rem 2rem;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background 0.2s;
}
.submit-btn:hover { background: var(--accent-lt); }

/* ── PAGE INTRO ──────────────────────────────── */
.page-intro {
  font-size: 1.2rem;
  color: var(--ink-mid);
  max-width: 100%;
  margin-bottom: 0rem;
}

/* ── FOOTER ──────────────────────────────────── */
.site-footer {
  text-align: center;
  padding: 1.5rem;
  font-size: 0.8rem;
  color: var(--ink-light);
  border-top: 1px solid var(--border);
  background: var(--paper-dark);
}

/* ── RESPONSIVE ──────────────────────────────── */
@media (max-width: 800px) {
  .banner { padding: 0 1.2rem; }
  .name-sub { display: none; }
  .about-section { grid-template-columns: 1fr; }
  .contact-grid  { grid-template-columns: 1fr; }
  .research-grid { grid-template-columns: 1fr; }
  .news-item     { grid-template-columns: 1fr; gap: 0.3rem; }
}

@media (max-width: 520px) {
  .banner { height: 60px; }
  .name-main { font-size: 1.2rem; }
  .nav-btn { font-size: 0.72rem; padding: 0.35rem 0.7rem; }
}

/* ── RESEARCH AREAS ──────────────────────────── */
.research-area {
  padding: 2.5rem 0;
  border-bottom: 1px solid var(--border);
}

.research-area:last-child {
  border-bottom: none;
}

.research-area-figure {
  float: none;
  width: 100%;
  margin: 1.2rem 0 0 0;
}

.research-area-figure img {
  width: 100%;
  max-height: 600px;
  object-fit: contain;
  border-radius: var(--radius);
  display: block;
}

.research-area-text h3 {
  margin-bottom: 0.8rem;
  font-family: var(--font-sans);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--ink);
}

.research-area-text p {
  font-size: 1.2rem;
  color: var(--ink-mid);
  line-height: 1.7;
  /* text-indent: 2em; */
}


.research-area::after {
  content: '';
  display: block;
  clear: both;
}

@media (max-width: 800px) {
  .research-area-figure {
    float: none;
    width: 100%;
    margin: 1rem 0;
  }
}

.figure-caption {
  font-size: 0.78rem;
  color: var(--ink-light);
  margin-top: 0.5rem;
  font-style: italic;
  text-align: center;
}