/* ========================================
   Zhi Wang's Academic Homepage — Redesigned
   Clean, warm, scholarly aesthetic
   ======================================== */

/* --- Google Fonts Import --- */
@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:wght@500;600;700;800;900&family=Inter:wght@400;500;600;700;800&family=Noto+Sans+SC:wght@400;500;700&family=Noto+Serif+SC:wght@500;600;700&display=swap');

/* --- CSS Variables --- */
:root {
  --color-text: #1e2d3d;
  --color-text-light: #4a5a6a;
  --color-heading: #0f1f2f;
  --color-link: #1e5a8a;
  --color-link-hover: #143f66;
  --color-accent: #82502a;
  --color-accent-light: #d4a574;
  --color-bg: #fafaf8;
  --color-surface: #ffffff;
  --color-border: #e0ddd7;
  --color-border-light: #f0eeea;
  --color-tag-bg: #f5f0eb;
  --color-section-bg: #fdfcfa;
  --font-body: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-heading: 'Playfair Display', 'Noto Serif SC', Georgia, 'Times New Roman', serif;
  --max-width: 900px;
  --transition: 0.25s ease;
}

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }

BODY {
  font-family: var(--font-body);
  font-size: 17px;
  font-weight: 450;
  line-height: 1.75;
  color: var(--color-text);
  background-color: var(--color-bg);
  margin: 0;
  padding: 0;
}

/* --- Main Container --- */
DIV.all {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 40px 32px 60px;
  background-color: transparent;
  width: auto;
}

/* --- Typography --- */
h1 {
  font-family: var(--font-heading);
  font-size: 2.6rem;
  font-weight: 800;
  color: var(--color-heading);
  margin: 0 0 8px 0;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

h2 {
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-heading);
  margin: 0 0 24px 0;
}

h3 {
  font-family: var(--font-heading);
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--color-heading);
  margin: 52px 0 18px 0;
  padding-bottom: 10px;
  padding-left: 14px;
  border-bottom: none;
  border-left: 4px solid var(--color-accent-light);
  background: linear-gradient(90deg, var(--color-section-bg) 0%, transparent 100%);
  border-radius: 0 6px 6px 0;
}

P { line-height: 1.8; margin: 0 0 18px 0; font-weight: 450; }

/* --- Links --- */
A:link, A:visited {
  color: var(--color-link);
  text-decoration: none;
  border: none;
  transition: color var(--transition);
}
A:active { color: var(--color-link); text-decoration: none; border: none; }
A:hover {
  color: var(--color-link-hover);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  border: none;
}

/* --- Profile Photo (table layout) --- */
table { border-collapse: collapse; width: 100%; }
table td { vertical-align: middle; padding: 0; }
table td:last-child { text-align: right; padding-left: 36px; }

IMG {
  border: none;
  max-width: 100%;
  height: auto;
}

table td img,
table td IMG {
  width: 250px;
  height: auto;
  border-radius: 14px;
  box-shadow: 0 6px 28px rgba(0,0,0,0.10);
  border: 3px solid var(--color-border-light);
}

/* --- Navigation Pills --- */
.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 18px 0 12px;
  margin: 8px 0 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.nav-links a {
  display: inline-block;
  padding: 8px 18px;
  font-size: 0.88rem;
  font-weight: 650;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-text-light);
  border-radius: 24px;
  border: 1.5px solid transparent;
  transition: all var(--transition);
  text-decoration: none;
}

.nav-links a:hover {
  color: var(--color-accent);
  background: var(--color-tag-bg);
  border-color: var(--color-accent-light);
  text-decoration: none;
}

/* --- Lists --- */
UL, ol { line-height: 1.8; padding-left: 22px; margin: 10px 0 18px; }
UL li, ol li { margin-bottom: 10px; padding-left: 6px; font-size: 1rem; font-weight: 450; }
ul li::marker { color: var(--color-accent-light); }
ol li::marker { color: var(--color-accent); font-weight: 600; }

/* --- Research Area Tags --- */
.research-areas {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  list-style: none;
  padding: 0;
  margin: 16px 0 0;
}
.research-areas li {
  background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-tag-bg) 100%);
  padding: 10px 22px;
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 650;
  color: var(--color-heading);
  margin-bottom: 0;
  border: 1.5px solid var(--color-border);
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  transition: all var(--transition);
}
.research-areas li:hover {
  box-shadow: 0 4px 16px rgba(0,0,0,0.08);
  transform: translateY(-1px);
  border-color: var(--color-accent-light);
}
.research-areas li strong { font-weight: 600; }
.research-areas li a {
  text-decoration: none;
  color: inherit;
  transition: color var(--transition);
}
.research-areas li a:hover {
  color: var(--color-link);
  text-decoration: none;
}

/* --- Research Group Cards --- */
.research-groups {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  list-style: none;
  padding: 0;
  margin: 16px 0 0;
}
.research-groups li {
  flex: 1 1 220px;
  background: var(--color-surface);
  padding: 18px 22px;
  border-radius: 12px;
  font-size: 0.95rem;
  font-weight: 650;
  color: var(--color-heading);
  border: 1.5px solid var(--color-border);
  box-shadow: 0 2px 10px rgba(0,0,0,0.04);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}
.research-groups li::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--color-accent-light);
  border-radius: 4px 0 0 4px;
}
.research-groups li:hover {
  box-shadow: 0 6px 20px rgba(0,0,0,0.08);
  transform: translateY(-2px);
  border-color: var(--color-accent-light);
}
.research-groups li a {
  text-decoration: none;
  color: var(--color-heading);
  display: block;
  transition: color var(--transition);
}
.research-groups li a:hover {
  color: var(--color-heading);
  text-decoration: none;
}
.group-name {
  display: block;
  font-weight: 650;
  font-size: 0.98rem;
  color: var(--color-heading);
  margin-bottom: 6px;
  transition: color var(--transition);
}
.research-groups li:hover .group-name {
  color: var(--color-link);
}
.group-desc {
  display: block;
  font-size: 0.84rem;
  font-weight: 430;
  line-height: 1.55;
  color: var(--color-text-light);
}
.research-groups li .group-arrow {
  color: var(--color-accent-light);
  font-size: 0.85em;
  margin-left: 6px;
  transition: transform var(--transition);
}
.research-groups li:hover .group-arrow {
  transform: translateX(3px);
}

/* --- Award highlight --- */
.award { color: #b33a2a !important; font-weight: 600; }

/* --- Publication & Paper Styles --- */
.author { text-decoration: none; font-weight: 450; }
.title { font-weight: 650; color: var(--color-link); border: none; cursor: pointer; }
.conference, .journal { font-style: italic; color: #5a3d82; font-weight: 600; }
.venue-abbr {
  font-style: normal;
  font-weight: 750;
  color: #3d2066;
  letter-spacing: 0.02em;
}
.hidden { color: var(--color-text-light); font-family: var(--font-body); font-size: 0.9em; font-weight: 450; }

div.block { width: 100%; padding: 0; margin: 0; }
div.abstract {
  display: none;
  padding: 16px 20px;
  margin: 8px 0 16px;
  width: 100%;
  max-width: 100%;
  line-height: 1.6;
  background-color: var(--color-tag-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 0.92rem;
  color: var(--color-text);
}
.abstract p { margin: 5px 0; }

ul.circle {
  list-style-type: none;
  line-height: 1.6;
  margin-left: 0;
  padding-left: 0;
}
li.list { padding-left: 10px; }
ul.none { padding-left: 10px; margin-left: 15px; list-style-type: none; }
li.paper { padding-left: 10px; margin-bottom: 12px; }

span.paper {
  display: block;
  padding: 14px 16px;
  margin: 6px 0;
  border-bottom: none;
  border-radius: 8px;
  transition: background var(--transition);
}
span.paper:hover {
  background: var(--color-section-bg);
}
span.paper p { margin: 4px 0; font-size: 0.95rem; line-height: 1.7; font-weight: 450; }

/* --- Note --- */
DIV.note { font-size: 0.8rem; float: right; color: var(--color-text-light); }

/* --- Subpage center headers --- */
center h2 {
  text-align: center;
  border-bottom: 2px solid var(--color-border);
  padding-bottom: 12px;
  margin-bottom: 32px;
}

/* --- Container / Legacy compat --- */
div.container { width: var(--max-width); }
div.header { width: var(--max-width); margin-top: 50px; margin-left: 40px; margin-bottom: 40px; padding-top: 1px; text-align: left; }
div.menu { width: 150px; text-align: center; float: left; }
div.photo { width: 200px; height: auto; margin-top: 0; margin-right: 0; border: none; }
div.contact { width: auto; padding: 15px; margin-bottom: -30px; text-align: left; border-radius: 10px; background-color: transparent; }
div.content { width: var(--max-width); text-align: left; }
div.title { color: var(--color-heading); }

nav.navbar { width: 100%; max-width: var(--max-width); height: auto; top: 0; font-family: var(--font-body); background: var(--color-heading); position: fixed; z-index: 100; padding: 0 20px; }
ul.navbar { list-style-type: none; margin: 0 auto; max-width: var(--max-width); height: auto; display: flex; padding: 0; }
li.navbar { height: 40px; margin: 0 16px; text-align: center; display: inline-flex; align-items: center; }
a.navbar { color: #aaa; text-decoration: none; display: block; font-size: 0.85rem; font-weight: 650; letter-spacing: 0.03em; text-transform: uppercase; }
a.navbar:hover { color: white; text-decoration: none; }

/* --- Top accent bar --- */
body::before {
  content: '';
  display: block;
  height: 4px;
  background: linear-gradient(90deg, var(--color-accent-light) 0%, var(--color-link) 50%, var(--color-accent-light) 100%);
}

/* --- Section icon labels --- */
.section-icon {
  display: inline-block;
  margin-right: 8px;
  font-size: 1.1em;
  vertical-align: middle;
}

/* --- Highlight card (for call-to-action like recruiting) --- */
.highlight-card {
  background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-tag-bg) 100%);
  border: 1.5px solid var(--color-border);
  border-left: 4px solid var(--color-accent-light);
  border-radius: 10px;
  padding: 20px 24px;
  margin: 12px 0 0;
  box-shadow: 0 2px 10px rgba(0,0,0,0.03);
}

/* --- Recruiting Banner --- */
.recruiting-banner {
  background: linear-gradient(135deg, #fcfaf6 0%, #f3ede4 100%);
  border: 1.5px solid var(--color-border);
  border-radius: 14px;
  padding: 28px 32px;
  margin: 12px 0 0;
  box-shadow: 0 3px 14px rgba(0,0,0,0.05);
  position: relative;
  overflow: hidden;
}
.recruiting-banner::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 4px;
  background: linear-gradient(90deg, var(--color-accent-light), var(--color-link), var(--color-accent-light));
}
.recruiting-header {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--color-accent);
  margin-bottom: 14px;
  letter-spacing: 0.01em;
}
.recruiting-banner p {
  font-size: 1rem;
  font-weight: 450;
  line-height: 1.75;
  margin-bottom: 12px;
}
.recruiting-topics {
  list-style: none;
  padding: 0;
  margin: 12px 0 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.recruiting-topics li {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 7px 16px;
  font-size: 0.9rem;
  font-weight: 550;
  color: var(--color-heading);
  box-shadow: 0 1px 4px rgba(0,0,0,0.03);
  margin-bottom: 0;
}
.recruiting-cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--color-border-light);
}
.cta-button {
  display: inline-block;
  padding: 10px 24px;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-surface) !important;
  background: linear-gradient(135deg, var(--color-link) 0%, #1e5a8a 100%);
  border-radius: 8px;
  text-decoration: none !important;
  transition: all var(--transition);
  box-shadow: 0 2px 8px rgba(42,100,150,0.25);
}
.cta-button:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(42,100,150,0.35);
  text-decoration: none !important;
  color: var(--color-surface) !important;
}
.cta-button-outline {
  background: transparent !important;
  color: var(--color-link) !important;
  border: 2px solid var(--color-link);
  box-shadow: none;
}
.cta-button-outline:hover {
  background: var(--color-link) !important;
  color: var(--color-surface) !important;
  box-shadow: 0 4px 14px rgba(42,100,150,0.25);
}

/* --- Footer credit --- */
.page-footer {
  margin-top: 60px;
  padding-top: 20px;
  border-top: 1px solid var(--color-border-light);
  text-align: center;
  font-size: 0.82rem;
  color: var(--color-text-light);
  letter-spacing: 0.02em;
}

/* --- Responsive --- */
@media (max-width: 700px) {
  DIV.all { padding: 24px 16px 40px; }
  table { display: flex; flex-direction: column-reverse; }
  table td { display: block; text-align: left !important; padding: 0 !important; }
  table td:last-child { text-align: center !important; margin-bottom: 20px; }
  table td img { width: 180px; }
  h1 { font-size: 2rem; }
  h2 { font-size: 1.6rem; }
  h3 { font-size: 1.2rem; }
  .nav-links { justify-content: center; }
  .research-areas { justify-content: center; }
  .research-groups li { flex: 1 1 100%; }
}

/* --- Print --- */
@media print {
  body { background: white; }
  body::before { display: none; }
  DIV.all { max-width: 100%; padding: 20px; }
  .nav-links { display: none; }
  .page-footer { display: none; }
  a { color: var(--color-text) !important; }
}