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

:root {
  --color-bg: #fafaf8;
  --color-text: #2c2c2c;
  --color-text-mid: #48484a;
  --color-text-light: #5a5a5a;
  --color-accent: #1a1a1a;
  --color-border: #e0ddd8;
  --color-border-light: #eceae5;
  --color-link: #3d3d3d;
  --color-link-hover: #000;
  --font-body: 'Source Serif 4', 'Georgia', serif;
  --font-nav: 'DM Sans', 'Helvetica Neue', sans-serif;
  --max-width: 920px;
  --nav-height: 60px;
}

html {
  font-size: 17px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* ===== Navigation ===== */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
}

nav .nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

nav .site-name {
  font-family: var(--font-nav);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-accent);
  text-decoration: none;
  letter-spacing: -0.01em;
}

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

nav .nav-links a {
  font-family: var(--font-nav);
  font-size: 0.85rem;
  font-weight: 400;
  color: var(--color-text-light);
  text-decoration: none;
  letter-spacing: 0.02em;
  transition: color 0.2s ease;
}

nav .nav-links a:hover,
nav .nav-links a.active {
  color: var(--color-accent);
}

/* Mobile menu toggle */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.menu-toggle span {
  display: block;
  width: 20px;
  height: 1.5px;
  background: var(--color-accent);
  margin: 5px 0;
  transition: all 0.3s ease;
}

/* ===== Main Content ===== */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 3.5rem 2rem 4rem;
}

/* ===== Home / About Layout ===== */
.home-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 3rem;
  align-items: start;
}

.home-photo img {
  width: 100%;
  border-radius: 3px;
}

.home-links {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-top: 1rem;
}

.home-links a {
  font-family: var(--font-nav);
  font-size: 0.84rem;
  font-weight: 400;
  color: var(--color-text-light);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: color 0.2s ease;
}

.home-links a:hover {
  color: var(--color-accent);
}

.home-links a svg {
  flex-shrink: 0;
  opacity: 0.5;
}

.home-text h1 {
  font-family: var(--font-body);
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: 0.2rem;
  letter-spacing: -0.02em;
}

.home-text .subtitle {
  font-family: var(--font-nav);
  font-size: 1.05rem;
  color: var(--color-text-light);
  margin-bottom: 0.4rem;
  letter-spacing: 0.01em;
}

.home-text .research-interests {
  font-family: var(--font-nav);
  font-size: 1.05rem;
  color: var(--color-text-light);
  margin-bottom: 1.5rem;
  letter-spacing: 0.01em;
}

.home-text p {
  margin-bottom: 1rem;
  color: var(--color-text);
  text-align: justify;
}

.home-text p:last-child {
  margin-bottom: 0;
}

.home-text a {
  color: var(--color-link);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: color 0.2s ease;
}

.home-text a:hover {
  color: var(--color-link-hover);
}

/* ===== Interior Pages ===== */
.page-header {
  margin-bottom: 2rem;
}

.page-header h1 {
  font-family: var(--font-body);
  font-size: 1.6rem;
  font-weight: 600;
  color: var(--color-accent);
  letter-spacing: -0.02em;
}

/* Research / Publications */
.section-group {
  margin-bottom: 2.5rem;
}

.section-group h2 {
  font-family: var(--font-nav);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-light);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-border);
}

.pub-item {
  margin-bottom: 1.4rem;
  padding-bottom: 1.4rem;
  border-bottom: 1px solid var(--color-border-light);
}

.pub-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.pub-item p {
  line-height: 1.65;
  text-align: justify;
}

.pub-item .pub-title {
  font-weight: 600;
  color: var(--color-accent);
}

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

.pub-item .pub-links {
  margin-top: 0.3rem;
}

.pub-item .pub-links a {
  font-family: var(--font-nav);
  font-size: 0.8rem;
  color: var(--color-text-light);
  text-decoration: none;
  margin-right: 1rem;
  transition: color 0.2s ease;
}

.pub-item .pub-links a:hover {
  color: var(--color-accent);
}

/* Teaching */
.teaching-item {
  margin-bottom: 1.1rem;
  padding-bottom: 1.1rem;
  border-bottom: 1px solid var(--color-border-light);
}

.teaching-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.teaching-item .course-title {
  font-weight: 600;
}

.teaching-item .course-detail {
  font-size: 0.9rem;
  color: var(--color-text-light);
}

/* Supervision text */
.supervision-text {
  color: var(--color-text);
  text-align: justify;
}

/* Book page */
.book-layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 2.5rem;
  align-items: start;
}

.book-cover img {
  width: 100%;
  border-radius: 2px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.1);
}

.book-text p {
  margin-bottom: 1rem;
  text-align: justify;
}

.book-text a {
  color: var(--color-link);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: color 0.2s ease;
}

.book-text a:hover {
  color: var(--color-link-hover);
}

/* CV page */
.cv-download {
  display: inline-block;
  margin-top: 1.5rem;
  padding: 0.6rem 1.4rem;
  font-family: var(--font-nav);
  font-size: 0.9rem;
  color: var(--color-accent);
  background: transparent;
  border: 1px solid var(--color-accent);
  text-decoration: none;
  letter-spacing: 0.02em;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.cv-download:hover {
  background-color: var(--color-accent);
  color: var(--color-bg);
}

/* ===== Footer ===== */
footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.5rem 2rem;
  border-top: 1px solid var(--color-border);
  font-family: var(--font-nav);
  font-size: 0.78rem;
  color: var(--color-text-light);
}

/* ===== Responsive ===== */
@media (max-width: 700px) {
  html {
    font-size: 16px;
  }

  .menu-toggle {
    display: block;
  }

  nav .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: 1rem 2rem;
    gap: 0.8rem;
  }

  nav .nav-links.open {
    display: flex;
  }

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

  .home-photo {
    max-width: 220px;
  }

  .home-text p {
    text-align: left;
  }

  .pub-item p {
    text-align: left;
  }

  .book-text p {
    text-align: left;
  }

  .supervision-text {
    text-align: left;
  }

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

  .book-cover {
    max-width: 180px;
  }

  main {
    padding: 2rem 1.2rem 3rem;
  }
}