/* =========================
   Base + Layout
   ========================= */

:root {
  --font-body: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --color-text: #1f2933;
  --color-muted: #6b7280;
  --color-border: #e5e7eb;
  --color-accent: #276fbf;      /* Main accent blue */
  --color-accent-soft: #e3efff; /* Soft blue background */
  --color-header-bg: #f9fafb;
  --color-body-bg: #f3f4f6;
  --color-card-bg: #ffffff;
  --shadow-soft: 0 10px 25px rgba(15, 23, 42, 0.06);
  --radius-lg: 12px;
  --radius-md: 8px;
  --radius-sm: 4px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-body);
  background-color: var(--color-body-bg);
  color: var(--color-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* A general container class (used in header & main) */
.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* =========================
   Typography & Links
   ========================= */

h1, h2, h3, h4 {
  margin-top: 0;
  font-weight: 600;
  color: #111827;
}

h1 {
  font-size: clamp(2.1rem, 2.8vw, 2.6rem);
  letter-spacing: 0.02em;
}

h2 {
  font-size: 1.6rem;
  margin-bottom: 0.75rem;
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 0.4rem;
}

h3 {
  font-size: 1.25rem;
  margin-top: 2rem;
  margin-bottom: 0.4rem;
}

h4 {
  font-size: 1.1rem;
  margin-top: 1.4rem;
  margin-bottom: 0.3rem;
}

p {
  font-size: 1rem;
  margin: 0.4rem 0 0.6rem;
  color: var(--color-text);
}

a {
  color: var(--color-accent);
  text-decoration: none;
  position: relative;
  transition: color 0.2s ease;
}

a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 0;
  height: 1px;
  background: var(--color-accent);
  transition: width 0.2s ease;
}

a:hover,
a:focus-visible {
  color: #1d4f8f;
}

a:hover::after,
a:focus-visible::after {
  width: 100%;
}

/* Don’t underline nav links with the generic link underline effect */
nav a::after,
.main-nav a::after {
  display: none;
}

/* Lists inside content */
main ul {
  padding-left: 1.3rem;
  margin-top: 0.4rem;
  margin-bottom: 0.8rem;
}

main li {
  margin-bottom: 0.4rem;
}

/* =========================
   Header + Navigation
   ========================= */

/* Support both <header> and .site-header */
header,
.site-header {
  background-color: var(--color-header-bg);
  border-bottom: 1px solid var(--color-border);
}

.site-header .container,
header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1rem;
  padding-bottom: 1rem;
  gap: 1rem;
}

.site-title {
  margin: 0;
}

.site-title a {
  color: #111827;
  text-decoration: none;
}

.site-title a:hover,
.site-title a:focus-visible {
  color: #111827;
}

/* Navigation – support both nav and .main-nav */
nav,
.main-nav {
  font-size: 0.95rem;
}

nav ul,
.main-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;

  display: flex;
  align-items: center;
  gap: 0.4rem;
}

nav li,
.main-nav li {
  margin: 0;
}

nav a,
.main-nav a {
  display: inline-block;
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  font-weight: 500;
  color: var(--color-muted);
  background: transparent;
  transition:
    background-color 0.2s ease,
    color 0.2s ease,
    transform 0.1s ease;
}

nav a:hover,
nav a:focus-visible,
.main-nav a:hover,
.main-nav a:focus-visible {
  background-color: var(--color-accent-soft);
  color: var(--color-accent);
  transform: translateY(-1px);
}

nav a.active,
.main-nav a.active,
nav a[aria-current="page"],
.main-nav a[aria-current="page"] {
  background-color: var(--color-accent);
  color: #ffffff;
}

/* =========================
   Main Content Card
   ========================= */

main {
  max-width: 960px;
  margin: 2.5rem auto 3rem;
  padding: 2rem 1.75rem;
  background-color: var(--color-card-bg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
}

/* Optional page title style */
.page-title {
  font-size: 1.8rem;
  margin-bottom: 1.5rem;
}

/* Section spacing */
main section {
  margin-top: 1.5rem;
}

/* =========================
   Section headings
   ========================= */

.section-heading {
  font-size: 1.3rem;
  margin-top: 2.5rem;
  margin-bottom: 1.25rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-border);
  letter-spacing: 0.01em;
}

/* =========================
   Research / Teaching cards
   ========================= */

.research-card {
  padding: 1.5rem 1.25rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background: var(--color-card-bg);
  margin-bottom: 1.25rem;
}

.research-card--highlight {
  background: linear-gradient(135deg, rgba(39, 111, 191, 0.04), rgba(39, 111, 191, 0.01));
  border-color: rgba(39, 111, 191, 0.18);
}

.research-card h3,
.research-card h4 {
  margin-top: 0.2rem;
  margin-bottom: 0.5rem;
  font-size: 1.1rem;
  line-height: 1.4;
}

/* Section label (small caps tag above titles) */
.section-label {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  background: var(--color-accent-soft);
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  margin-bottom: 0.5rem;
}

/* =========================
   Meta grid
   ========================= */

.meta-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.5rem;
  margin-top: 1rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--color-border);
  font-size: 0.92rem;
}

.meta-label {
  display: inline-block;
  font-weight: 600;
  color: var(--color-muted);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  min-width: 5.5rem;
  margin-right: 0.4rem;
}

.meta-item {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.15rem;
}

/* Keyword pills */
.keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.kw {
  display: inline-block;
  font-size: 0.8rem;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  background: #f3f4f6;
  color: #4b5563;
  border: 1px solid #e5e7eb;
}

/* =========================
   Publication groups
   ========================= */

.pub-group {
  margin-bottom: 1.5rem;
}

.pub-status {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  padding: 0.25rem 0.7rem;
  border-radius: 999px;
  margin-top: 0;
  margin-bottom: 0.75rem;
}

.pub-status--submitted {
  color: #b45309;
  background: #fef3c7;
}

.pub-status--accepted {
  color: #0369a1;
  background: #e0f2fe;
}

.pub-status--published {
  color: #15803d;
  background: #dcfce7;
}

.pub-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.pub-item {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  padding: 0.75rem 0.85rem;
  border-left: 3px solid var(--color-border);
  margin-bottom: 0.65rem;
  background: #fafbfc;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  transition: border-color 0.15s ease;
}

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

.pub-authors {
  font-size: 0.88rem;
  color: var(--color-muted);
}

.pub-title {
  font-weight: 600;
  font-size: 0.95rem;
  color: #111827;
  line-height: 1.45;
}

.pub-venue {
  font-size: 0.88rem;
  color: var(--color-muted);
}

/* =========================
   Thesis document links
   ========================= */

.thesis-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0.75rem 0;
}

.doc-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.85rem;
  font-weight: 500;
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background: #fafbfc;
  color: var(--color-accent);
  transition: background-color 0.15s ease, border-color 0.15s ease;
}

.doc-link::after {
  display: none;
}

.doc-link:hover {
  background: var(--color-accent-soft);
  border-color: var(--color-accent);
}

.doc-link svg {
  flex-shrink: 0;
}

/* Talk note */
.talk-note {
  font-size: 0.9rem;
  color: var(--color-muted);
  margin-top: 0.75rem;
  font-style: italic;
}

.talk-note a {
  font-style: normal;
}

/* =========================
   Teaching: semester headings
   ========================= */

.semester-heading {
  font-size: 0.82rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--color-accent);
  margin-top: 1.8rem;
  margin-bottom: 0.6rem;
}

/* =========================
   Horizontal rules
   ========================= */

main hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 2rem 0;
}

/* =========================
   Footer
   ========================= */

.site-footer {
  text-align: center;
  padding: 1.5rem 1rem 2rem;
  font-size: 0.9rem;
  color: var(--color-muted);
}

/* =========================
   Responsive
   ========================= */

@media (max-width: 700px) {
  .site-header .container,
  header .container {
    flex-direction: column;
    align-items: flex-start;
  }

  nav ul,
  .main-nav ul {
    flex-wrap: wrap;
    justify-content: flex-start;
  }

  main {
    margin: 1.5rem auto 2.5rem;
    padding: 1.5rem 1.25rem;
  }

  h1 {
    font-size: 2rem;
  }

  .page-title {
    font-size: 1.5rem;
  }
}