/* ===== Google Fonts ===== */
@import url('https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,300;0,400;0,500;0,700;1,400;1,700&family=Droid+Sans:ital,wght@0,400;0,700&display=swap');

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

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

body {
  font-family: 'Roboto', 'Droid Sans', Helvetica, Arial, sans-serif;
  background-color: #fff;
  color: #1a1a1a;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

a {
  color: #1a1a1a;
  text-decoration: underline;
  text-decoration-color: #ccc;
  text-underline-offset: 2px;
  transition: color 0.15s, text-decoration-color 0.15s;
}

a:hover {
  color: #000;
  text-decoration-color: #1a1a1a;
}

/* ===== Navigation ===== */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #fff;
  border-bottom: 1px solid #e8e8e8;
  padding: 0 2.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.nav-left {
  display: flex;
  align-items: center;
  gap: 2.5rem;
}

.nav-brand a {
  font-family: 'Roboto', sans-serif;
  font-size: 0.9rem;
  font-weight: 500;
  color: #111;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  text-decoration: none;
  white-space: nowrap;
}

.nav-brand a:hover {
  text-decoration: none;
  color: #000;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.8rem;
  list-style: none;
}

.nav-links li a {
  font-family: 'Roboto', sans-serif;
  font-size: 0.8rem;
  font-weight: 400;
  color: #777;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  padding-bottom: 3px;
  border-bottom: 1.5px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

.nav-links li a:hover,
.nav-links li a.active {
  color: #111;
  border-bottom-color: #111;
}

.nav-icons {
  display: flex;
  align-items: center;
  gap: 1.1rem;
}

.nav-icons a {
  display: inline-flex;
  align-items: center;
  color: #999;
  text-decoration: none;
  transition: color 0.15s;
}

.nav-icons a:hover {
  color: #111;
}

.nav-icons svg {
  width: 17px;
  height: 17px;
  fill: currentColor;
}

/* ===== Main Layout ===== */
main {
  max-width: 780px;
  margin: 0 auto;
  padding: 4rem 2.5rem 6rem;
}

/* ===== Page Header ===== */
.page-header {
  margin-bottom: 3rem;
  padding-bottom: 1.8rem;
  border-bottom: 1px solid #eee;
}

.page-header h1 {
  font-family: 'Roboto', sans-serif;
  font-size: 1.6rem;
  font-weight: 300;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #111;
  margin-bottom: 0.3rem;
}

.page-header .subtitle {
  font-size: 0.9rem;
  color: #888;
  font-weight: 400;
}

/* ===== Section Title ===== */
.section-title {
  font-family: 'Roboto', sans-serif;
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: #aaa;
  margin-bottom: 1.2rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid #eee;
}

/* ===== Home Page - Hero ===== */
.home-hero {
  display: grid;
  grid-template-columns: 1fr 220px;
  gap: 3.5rem;
  align-items: start;
  margin-bottom: 4rem;
  padding-bottom: 3rem;
  border-bottom: 1px solid #eee;
}

.home-hero-text {}

.home-header h1 {
  font-family: 'Roboto', sans-serif;
  font-size: 2rem;
  font-weight: 300;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #111;
  margin-bottom: 0.4rem;
  line-height: 1.2;
}

.home-header .tagline {
  font-size: 0.88rem;
  color: #888;
  font-weight: 400;
  margin-bottom: 1.5rem;
  letter-spacing: 0.02em;
}

.home-hero-photo {
  position: relative;
}

.home-hero-photo img {
  width: 100%;
  aspect-ratio: 3/4;
  object-fit: cover;
  display: block;
  filter: grayscale(8%);
}

section {
  margin-bottom: 3.2rem;
}

section p {
  font-family: 'Roboto', sans-serif;
  font-size: 0.95rem;
  color: #333;
  line-height: 1.85;
  margin-bottom: 0.85rem;
  font-weight: 300;
}

section p:last-child {
  margin-bottom: 0;
}

section p a {
  color: #333;
  font-weight: 400;
}

section p a:hover {
  color: #000;
}

/* ===== Experience / Timeline entries ===== */
.exp-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.exp-item {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 0 1.5rem;
  padding: 0.65rem 0;
  border-bottom: 1px solid #f5f5f5;
  align-items: baseline;
}

.exp-item:last-child {
  border-bottom: none;
}

.exp-year {
  font-size: 0.78rem;
  color: #bbb;
  font-weight: 400;
  white-space: nowrap;
  padding-top: 0.1rem;
}

.exp-content {
  font-size: 0.92rem;
  color: #333;
  line-height: 1.55;
}

.exp-content strong {
  font-weight: 500;
  color: #111;
}

.exp-content .exp-sub {
  font-size: 0.82rem;
  color: #888;
  display: block;
  margin-top: 0.1rem;
}

/* ===== Method Tags ===== */
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.4rem;
}

.tag {
  background: #f7f7f7;
  color: #555;
  font-size: 0.78rem;
  font-weight: 400;
  padding: 0.25rem 0.75rem;
  border-radius: 2rem;
  border: 1px solid #e8e8e8;
  letter-spacing: 0.02em;
}

/* ===== CV Button ===== */
.cv-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  margin-top: 0.6rem;
  padding: 0.45rem 1.1rem;
  border: 1px solid #ccc;
  color: #444;
  border-radius: 2px;
  font-size: 0.82rem;
  font-weight: 400;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  text-decoration: none;
  transition: border-color 0.15s, color 0.15s, background 0.15s;
}

.cv-link:hover {
  background: #111;
  border-color: #111;
  color: #fff;
  text-decoration: none;
}

/* ===== Research Paper Cards ===== */
.paper-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.paper {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 0 2rem;
  padding: 2.2rem 0;
  border-bottom: 1px solid #f0f0f0;
  align-items: start;
}

.paper:first-child {
  padding-top: 0;
}

.paper:last-child {
  border-bottom: none;
}

.paper-thumb {
  width: 140px;
  flex-shrink: 0;
}

.paper-thumb img {
  width: 100%;
  display: block;
  aspect-ratio: 4/3;
  object-fit: cover;
  border: 1px solid #eee;
}

.paper-body {}

.paper-title {
  font-family: 'Roboto', sans-serif;
  font-size: 0.97rem;
  font-weight: 500;
  color: #111;
  line-height: 1.5;
  margin-bottom: 0.35rem;
}

.paper-title a {
  color: #111;
  text-decoration: none;
}

.paper-title a:hover {
  text-decoration: underline;
  text-decoration-color: #111;
}

.paper-meta {
  font-size: 0.82rem;
  color: #888;
  margin-bottom: 0.6rem;
  line-height: 1.55;
}

.paper-meta em {
  font-style: italic;
  color: #666;
}

.paper-meta .coauthor {
  color: #999;
}

.paper-award {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.75rem;
  color: #92400e;
  background: #fef3c7;
  border: 1px solid #fde68a;
  padding: 0.18rem 0.6rem;
  border-radius: 2px;
  margin-bottom: 0.6rem;
  font-weight: 400;
  letter-spacing: 0.02em;
}

.paper-status {
  display: inline-block;
  font-size: 0.73rem;
  color: #2563eb;
  background: #eff6ff;
  border: 1px solid #bfdbfe;
  padding: 0.15rem 0.55rem;
  border-radius: 2px;
  margin-bottom: 0.55rem;
  letter-spacing: 0.03em;
  font-weight: 400;
}

/* Toggle abstract */
.abstract-toggle {
  background: none;
  border: none;
  font-size: 0.79rem;
  color: #999;
  cursor: pointer;
  padding: 0;
  margin-top: 0.35rem;
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-family: 'Roboto', sans-serif;
  font-weight: 400;
}

.abstract-toggle:hover {
  color: #333;
}

.abstract-toggle .toggle-arrow {
  display: inline-block;
  transition: transform 0.2s;
  font-size: 0.7rem;
}

.abstract-toggle.open .toggle-arrow {
  transform: rotate(90deg);
}

.abstract-content {
  margin-top: 0.75rem;
  font-size: 0.87rem;
  color: #555;
  line-height: 1.8;
  display: none;
  font-weight: 300;
  border-left: 2px solid #eee;
  padding-left: 1rem;
}

.abstract-content.open {
  display: block;
}

/* ===== Dataset Cards ===== */
.dataset-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.dataset {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 0 2rem;
  padding: 2.5rem 0;
  border-bottom: 1px solid #f0f0f0;
  align-items: start;
}

.dataset:first-child {
  padding-top: 0;
}

.dataset:last-child {
  border-bottom: none;
}

.dataset-thumb {
  width: 160px;
  flex-shrink: 0;
}

.dataset-thumb img {
  width: 100%;
  display: block;
  aspect-ratio: 4/3;
  object-fit: cover;
  border: 1px solid #eee;
}

.dataset-body {}

.dataset-title {
  font-family: 'Roboto', sans-serif;
  font-size: 0.97rem;
  font-weight: 500;
  color: #111;
  margin-bottom: 0.3rem;
  line-height: 1.45;
}

.dataset-title a {
  color: #111;
  text-decoration: none;
}

.dataset-title a:hover {
  text-decoration: underline;
  text-decoration-color: #111;
}

.dataset-pi {
  font-size: 0.8rem;
  color: #999;
  margin-bottom: 0.7rem;
  font-style: italic;
}

.dataset-body p {
  font-size: 0.9rem;
  color: #444;
  line-height: 1.75;
  margin-bottom: 0.5rem;
  font-weight: 300;
}

.dataset-link {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.78rem;
  color: #777;
  text-decoration: none;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  border-bottom: 1px solid #ccc;
  padding-bottom: 1px;
  transition: color 0.15s, border-color 0.15s;
}

.dataset-link:hover {
  color: #111;
  border-color: #111;
  text-decoration: none;
}

/* ===== Teaching ===== */
.teaching-section {
  margin-bottom: 2.8rem;
}

.teaching-subsection {
  margin-bottom: 1.8rem;
}

.teaching-role {
  font-family: 'Roboto', sans-serif;
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: #bbb;
  margin-bottom: 0.7rem;
}

.course-list {
  list-style: none;
  padding: 0;
}

.course-list li {
  font-size: 0.91rem;
  color: #333;
  padding: 0.45rem 0;
  border-bottom: 1px solid #f5f5f5;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  line-height: 1.5;
  font-weight: 300;
}

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

.course-name {
  flex: 1;
}

.course-name a {
  color: #333;
  text-decoration: none;
}

.course-name a:hover {
  text-decoration: underline;
  text-decoration-color: #555;
  color: #111;
}

.course-level {
  font-size: 0.73rem;
  color: #bbb;
  white-space: nowrap;
  font-weight: 400;
}

/* ===== Resources ===== */
.resource-section {
  margin-bottom: 2.5rem;
}

.resource-list {
  list-style: none;
  padding: 0;
}

.resource-list li {
  font-size: 0.9rem;
  color: #333;
  padding: 0.45rem 0;
  border-bottom: 1px solid #f5f5f5;
  line-height: 1.6;
  font-weight: 300;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

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

.resource-list li a {
  color: #333;
  font-weight: 400;
}

.resource-list li a:hover {
  color: #111;
}

.resource-desc {
  font-size: 0.8rem;
  color: #aaa;
  font-style: italic;
}

/* ===== Connect ===== */
.connect-intro {
  font-size: 0.93rem;
  color: #444;
  line-height: 1.8;
  margin-bottom: 2.5rem;
  font-weight: 300;
}

.connect-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-bottom: 3rem;
}

.connect-card {
  background: #fafafa;
  border: 1px solid #eee;
  border-radius: 3px;
  padding: 1.5rem 1.6rem;
}

.connect-card h3 {
  font-family: 'Roboto', sans-serif;
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: #bbb;
  margin-bottom: 0.7rem;
}

.connect-card p {
  font-size: 0.9rem;
  color: #444;
  font-weight: 300;
  line-height: 1.65;
}

.connect-card a {
  font-size: 0.9rem;
  color: #333;
  font-weight: 400;
}

/* Contact Form */
.contact-form-section h2 {
  font-family: 'Roboto', sans-serif;
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: #aaa;
  margin-bottom: 1.2rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid #eee;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
  margin-top: 0.8rem;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.form-group label {
  font-size: 0.78rem;
  font-weight: 500;
  color: #888;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.form-group input,
.form-group textarea {
  border: 1px solid #ddd;
  border-radius: 2px;
  padding: 0.6rem 0.85rem;
  font-size: 0.9rem;
  font-family: 'Roboto', inherit;
  font-weight: 300;
  color: #222;
  outline: none;
  transition: border-color 0.15s;
  background: #fff;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: #666;
}

.form-group textarea {
  resize: vertical;
  min-height: 130px;
  line-height: 1.7;
}

.form-submit {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1.6rem;
  background: #111;
  color: #fff;
  border: none;
  border-radius: 2px;
  font-size: 0.8rem;
  font-family: 'Roboto', inherit;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
  transition: background 0.15s;
  align-self: flex-start;
}

.form-submit:hover {
  background: #333;
}

/* ===== Footer ===== */
footer {
  text-align: center;
  padding: 2rem 1rem 3rem;
  font-size: 0.76rem;
  color: #ccc;
  border-top: 1px solid #eee;
  font-weight: 300;
  letter-spacing: 0.03em;
}

footer a {
  color: #bbb;
  font-weight: 400;
}

footer a:hover {
  color: #888;
}

/* ===== Responsive ===== */
@media (max-width: 700px) {
  nav {
    padding: 0 1.2rem;
    flex-wrap: wrap;
    height: auto;
    padding-top: 0.6rem;
    padding-bottom: 0.6rem;
    gap: 0.5rem;
  }

  .nav-left {
    flex-wrap: wrap;
    gap: 0.9rem;
  }

  .nav-links {
    gap: 1rem;
  }

  main {
    padding: 2.5rem 1.4rem 4rem;
  }

  .home-hero {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .home-hero-photo {
    order: -1;
    max-width: 180px;
  }

  .home-header h1 {
    font-size: 1.6rem;
  }

  .paper {
    grid-template-columns: 1fr;
    gap: 1rem 0;
  }

  .paper-thumb {
    width: 100%;
    max-width: 200px;
  }

  .dataset {
    grid-template-columns: 1fr;
    gap: 1rem 0;
  }

  .dataset-thumb {
    width: 100%;
    max-width: 220px;
  }

  .connect-grid {
    grid-template-columns: 1fr;
  }

  .form-row {
    grid-template-columns: 1fr;
  }
}