/* =====================================================================
   DESIGN TOKENS
   ===================================================================== */
:root {
  --font-serif:   'Newsreader', 'Iowan Old Style', Georgia, serif;
  --font-display: 'Fraunces', 'Iowan Old Style', Georgia, serif;
  --font-sans:    'IBM Plex Sans', system-ui, -apple-system, sans-serif;

  --accent:      #1e3a5f;   /* deep ink navy */
  --accent-dim:  #e1e7ef;   /* faint navy on paper */
  --text:        #1c1814;   /* warm ink */
  --muted:       #6b6457;   /* warm gray */
  --border:      #e2d9c8;   /* warm tan */
  --bg:          #faf7f2;   /* warm paper */
  --bg-alt:      #f3ede0;   /* cream */
  --max-w:       740px;
  --section-gap: 5rem;
}

/* =====================================================================
   RESET & BASE
   ===================================================================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font-serif);
  color: var(--text);
  background-color: var(--bg);
  background-image: radial-gradient(circle, #d8ccb2 2px, transparent 2px);
  background-size: 24px 24px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

h1, h2, h3 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.01em;
}

ul { list-style: none; }

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

/* =====================================================================
   LAYOUT HELPERS
   ===================================================================== */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 1.5rem;
}

section {
  padding: var(--section-gap) 0;
  background: linear-gradient(
    to right,
    transparent calc(50% - 385px),
    var(--bg) calc(50% - 370px),
    var(--bg) calc(50% + 370px),
    transparent calc(50% + 385px)
  );
}
section:nth-of-type(even) {
  background: linear-gradient(
    to right,
    transparent calc(50% - 385px),
    var(--bg-alt) calc(50% - 370px),
    var(--bg-alt) calc(50% + 370px),
    transparent calc(50% + 385px)
  );
}

.section-label {
  font-family: var(--font-sans);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.6rem;
}

.section-title {
  font-size: 1.6rem;
  font-variation-settings: "opsz" 36;
  margin-bottom: 2rem;
  color: var(--text);
}

/* =====================================================================
   TOP NAV
   ===================================================================== */
#topnav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 247, 242, 0.9);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

#topnav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 3.5rem;
  gap: 1rem;
}

#topnav .nav-name {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--text);
  white-space: nowrap;
  flex-shrink: 0;
  letter-spacing: -0.01em;
}

#topnav .nav-name:hover { text-decoration: none; color: var(--accent); }

#topnav nav {
  display: flex;
  gap: 0.25rem;
  flex-wrap: wrap;
  justify-content: flex-end;
}

#topnav nav a {
  font-family: var(--font-sans);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--muted);
  padding: 0.3rem 0.6rem;
  border-radius: 4px;
  transition: color 0.15s, background 0.15s;
}

#topnav nav a:hover,
#topnav nav a.active {
  color: var(--accent);
  background: var(--accent-dim);
  text-decoration: none;
}

/* =====================================================================
   HERO
   ===================================================================== */
#hero {
  padding: 5rem 0 4rem;
  background: linear-gradient(
    to right,
    transparent calc(50% - 385px),
    var(--bg) calc(50% - 370px),
    var(--bg) calc(50% + 370px),
    transparent calc(50% + 385px)
  );
}

.hero-inner {
  display: flex;
  align-items: flex-start;
  gap: 2.5rem;
}

.avatar-photo {
  width: 112px;
  height: 112px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  border: 3px solid var(--border);
}

.hero-text h1 {
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 4vw, 2.3rem);
  font-variation-settings: "opsz" 72, "SOFT" 50;
  font-weight: 500;
  margin-bottom: 0.9rem;
  letter-spacing: 0;
  display: inline-block;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}

.hero-tagline {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 1.1rem;
  color: var(--text);
  margin-bottom: 0.25rem;
}

.hero-inst {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--muted);
  margin-bottom: 1.5rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.hero-links a {
  font-family: var(--font-sans);
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--muted);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 0.3rem 0.85rem;
  transition: color 0.15s, border-color 0.15s;
}

.hero-links a:hover {
  color: var(--accent);
  border-color: var(--accent);
  text-decoration: none;
}

/* =====================================================================
   ABOUT
   ===================================================================== */
#about p {
  font-size: 1.075rem;
  color: var(--text);
  max-width: 640px;
  margin-bottom: 1rem;
  line-height: 1.7;
}

/* =====================================================================
   PUBLICATIONS / PUB LIST
   ===================================================================== */
.pub-list { display: flex; flex-direction: column; gap: 1.5rem; }

.pub-item {
  padding-left: 1rem;
  border-left: 2px solid var(--border);
  transition: border-color 0.15s;
}

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

.pub-title {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text);
  margin-bottom: 0.2rem;
  line-height: 1.4;
}

.pub-authors {
  font-family: var(--font-sans);
  font-size: 0.82rem;
  font-weight: 400;
  color: var(--muted);
  margin-bottom: 0.15rem;
}

.pub-venue {
  font-family: var(--font-serif);
  font-size: 0.92rem;
  color: var(--muted);
}

.pub-venue em { font-style: italic; color: var(--text); }

.pub-title a { color: var(--text); }

.pub-title a:hover {
  color: var(--accent);
  text-decoration: underline;
}

.pub-badge {
  font-family: var(--font-sans);
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 500;
  background: var(--accent-dim);
  color: var(--accent);
  border-radius: 2px;
  padding: 0.12rem 0.5rem;
  margin-left: 0.5rem;
  vertical-align: middle;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* =====================================================================
   SUBSECTION TITLES & PROJECT LIST
   ===================================================================== */
.subsection-title {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}

.project-list li {
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--border);
  font-family: var(--font-serif);
  font-size: 1rem;
  color: var(--text);
  line-height: 1.55;
}

.project-list li:last-child { border-bottom: none; }

.project-list li strong { color: var(--text); font-weight: 500; }

.project-collab {
  font-family: var(--font-serif);
  font-style: italic;
  display: block;
  font-size: 0.9rem;
  color: var(--muted);
  margin-top: 0.25rem;
}

/* =====================================================================
   RESEARCH — interactive two-column layout
   ===================================================================== */
.research-layout {
  display: grid;
  grid-template-columns: 175px 1fr;
  gap: 3rem;
  align-items: start;
}

.research-sidebar {
  position: sticky;
  top: 4.5rem;
}

.sidebar-label {
  font-family: var(--font-sans);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.75rem;
}

.theme-pills {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.theme-pill {
  display: block;
  width: 100%;
  padding: 0.4rem 0.85rem;
  border-radius: 20px;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--muted);
  background: var(--bg);
  border: 1px solid var(--border);
  cursor: pointer;
  text-align: left;
  line-height: 1.4;
  transition: color 0.15s, background 0.15s, border-color 0.15s;
}

.theme-pill:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-dim);
}

.theme-pill.active {
  color: var(--accent);
  background: var(--accent-dim);
  border-color: var(--accent);
  font-weight: 600;
}

.research-narrative { min-width: 0; }

.research-para {
  font-family: var(--font-serif);
  font-size: 1.075rem;
  color: var(--text);
  margin-bottom: 1.25rem;
  padding: 0.5rem 0.75rem;
  margin-left: -0.75rem;
  border-radius: 6px;
  line-height: 1.7;
}

.research-para:last-child { margin-bottom: 0; }

@keyframes highlight-fade {
  0%   { background-color: #f5e9c4; }
  65%  { background-color: #f5e9c4; }
  100% { background-color: transparent; }
}

.research-para.highlight {
  animation: highlight-fade 2s ease forwards;
}

/* =====================================================================
   TEACHING — summary list (homepage)
   ===================================================================== */
.course-list { display: flex; flex-direction: column; gap: 0.75rem; }

.course-item {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  flex-wrap: wrap;
}

.course-name {
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 500;
  color: var(--text);
}

.course-meta {
  font-family: var(--font-sans);
  font-size: 0.74rem;
  font-weight: 500;
  color: var(--muted);
  white-space: nowrap;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

/* =====================================================================
   TEACHING — detailed course cards (teaching page)
   ===================================================================== */
.placeholder-note {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 1rem;
  color: var(--muted);
  padding: 1.5rem;
  border: 1px dashed var(--border);
  border-radius: 6px;
  text-align: center;
}

.course-cards {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.course-card {
  padding: 1.5rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg);
}

.course-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.course-card-title {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text);
  line-height: 1.3;
  letter-spacing: -0.01em;
}

.course-tags {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  flex-shrink: 0;
}

.course-tag {
  font-family: var(--font-sans);
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 500;
  background: var(--accent-dim);
  color: var(--accent);
  border-radius: 2px;
  padding: 0.18rem 0.5rem;
  white-space: nowrap;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.course-desc {
  font-family: var(--font-serif);
  font-size: 1rem;
  color: var(--text);
  line-height: 1.7;
  margin-bottom: 1.25rem;
}

.course-topics-label {
  font-family: var(--font-sans);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.4rem;
  margin-top: 0.75rem;
}

.course-topics-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.course-topics-list li {
  font-family: var(--font-serif);
  font-size: 0.95rem;
  color: var(--text);
  padding-left: 1rem;
  position: relative;
}

.course-topics-list li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--muted);
}

.course-materials-note {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 0.88rem;
  color: var(--muted);
  margin-top: 1.25rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border);
}

.course-materials {
  margin-top: 1.25rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border);
}

/* =====================================================================
   CV
   ===================================================================== */
#cv { text-align: center; }

#cv p {
  font-family: var(--font-serif);
  color: var(--muted);
  font-size: 1.05rem;
  margin-bottom: 2rem;
  max-width: 480px;
  margin-left: auto;
  margin-right: auto;
}

.btn-primary {
  font-family: var(--font-sans);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--accent);
  color: var(--bg);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.75rem 1.75rem;
  border-radius: 4px;
  letter-spacing: 0.02em;
  transition: opacity 0.15s, transform 0.15s;
}

.btn-primary:hover {
  opacity: 0.92;
  text-decoration: none;
  transform: translateY(-1px);
}

/* =====================================================================
   VIEW-MORE LINK
   ===================================================================== */
.view-more {
  font-family: var(--font-sans);
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  margin-top: 1.75rem;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--accent);
  letter-spacing: 0.02em;
}

.view-more:hover { text-decoration: underline; }

/* =====================================================================
   PAGE HEADER (sub-pages)
   ===================================================================== */
.page-header {
  padding: 4rem 0 3rem;
  background: linear-gradient(
    to right,
    transparent calc(50% - 385px),
    var(--bg) calc(50% - 370px),
    var(--bg) calc(50% + 370px),
    transparent calc(50% + 385px)
  );
  border-bottom: 1px solid var(--border);
}

.page-header .section-label { margin-bottom: 0.4rem; }

.page-header h1 {
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 500;
  font-size: clamp(2rem, 5.5vw, 3rem);
  font-variation-settings: "opsz" 96, "SOFT" 50;
  letter-spacing: -0.015em;
}

.page-header h1 .amp {
  font-style: normal;
  font-weight: 400;
  color: var(--muted);
  margin: 0 0.05em;
}

/* =====================================================================
   FOOTER
   ===================================================================== */
footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  text-align: center;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  color: var(--muted);
  letter-spacing: 0.02em;
  background: linear-gradient(
    to right,
    transparent calc(50% - 385px),
    var(--bg) calc(50% - 370px),
    var(--bg) calc(50% + 370px),
    transparent calc(50% + 385px)
  );
}

footer a { color: var(--muted); }
footer a:hover { color: var(--accent); }

/* =====================================================================
   COURSE PAGE — back link, intro, lecture notes
   ===================================================================== */
.back-link {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--muted);
  letter-spacing: 0.02em;
  margin-bottom: 0.85rem;
}

.back-link:hover {
  color: var(--accent);
  text-decoration: none;
}

#course-intro p,
#blog-intro p {
  font-size: 1.075rem;
  color: var(--text);
  max-width: 640px;
  margin-bottom: 1rem;
  line-height: 1.7;
}

.post-excerpt {
  font-family: var(--font-serif);
  font-size: 0.95rem;
  color: var(--text);
  margin-top: 0.4rem;
  line-height: 1.6;
}

.course-page-tags {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  margin-bottom: 1.25rem;
}

.lecture-list {
  list-style: none;
  display: flex;
  flex-direction: column;
}

.lecture-list li {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--border);
  font-family: var(--font-serif);
}

.lecture-list li:last-child { border-bottom: none; }

.lec-num {
  flex-shrink: 0;
  width: 2rem;
  font-family: var(--font-display);
  font-style: italic;
  font-variation-settings: "opsz" 24;
  color: var(--muted);
  font-size: 1.05rem;
  text-align: right;
  padding-right: 0.5rem;
}

.lec-title {
  flex: 1;
  font-size: 1.025rem;
  color: var(--text);
  line-height: 1.4;
}

.lec-pdfs {
  display: inline-flex;
  gap: 0.5rem;
  flex-shrink: 0;
}

.lec-pdf {
  font-family: var(--font-sans);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  white-space: nowrap;
  border: 1px solid var(--border);
  border-radius: 2px;
  padding: 0.22rem 0.6rem;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
}

.lec-pdf:hover {
  text-decoration: none;
  border-color: var(--accent);
  background: var(--accent-dim);
}

/* =====================================================================
   RESPONSIVE
   ===================================================================== */
@media (max-width: 900px) {
  body {
    background-image: none;
  }
  #hero, .page-header, section, section:nth-of-type(even), footer {
    background: var(--bg);
  }
  section:nth-of-type(even) {
    background: var(--bg-alt);
  }
}

@media (max-width: 600px) {
  :root { --section-gap: 3.5rem; }

  .hero-inner { flex-direction: column; gap: 1.5rem; }

  .avatar-photo { width: 80px; height: 80px; }

  #topnav nav a { font-size: 0.76rem; padding: 0.25rem 0.45rem; }

  .research-layout {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .research-sidebar { position: static; }

  .theme-pills { flex-direction: row; flex-wrap: wrap; }

  .theme-pill { width: auto; }

  .course-item { flex-direction: column; gap: 0.25rem; }

}