/* ============================================
   Edward Kim - Academic Website
   Shared Stylesheet
   ============================================ */

/* --- CSS Custom Properties --- */
:root {
  --color-bg-dark: #ffffff;
  --color-bg-alt: #f7f8fa;
  --color-bg-card: #ffffff;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-text-primary: #374151;
  --color-text-muted: #6b7280;
  --color-text-heading: #111827;
  --color-text-white: #ffffff;
  --color-border: #e5e7eb;
  --color-shadow: rgba(0, 0, 0, 0.08);

  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto,
    'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Fira Mono', 'Roboto Mono', monospace;

  --nav-height: 70px;
  --max-width: 1100px;
  --transition: 0.25s cubic-bezier(0.645, 0.045, 0.355, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg-dark);
  color: var(--color-text-primary);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

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

ul {
  list-style: none;
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 1000;
  border-bottom: 1px solid var(--color-border);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-heading);
  letter-spacing: -0.02em;
}

.nav-logo span {
  color: var(--color-accent);
}

.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.nav-links a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  position: relative;
  padding: 0.25rem 0;
  transition: color var(--transition);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-accent);
  transition: width var(--transition);
}

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

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0.5rem;
}

.nav-toggle span {
  display: block;
  width: 25px;
  height: 2px;
  background-color: var(--color-text-heading);
  transition: var(--transition);
}

/* --- Navbar variant (used by publications, cv, teaching, lab pages) --- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 1000;
  border-bottom: 1px solid var(--color-border);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-heading);
  letter-spacing: -0.02em;
  text-decoration: none;
}

.nav-brand:hover {
  color: var(--color-accent);
}

.nav-menu {
  display: flex;
  gap: 2rem;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-menu li a,
.nav-link {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  position: relative;
  padding: 0.25rem 0;
  transition: color var(--transition);
  text-decoration: none;
}

.nav-menu li a::after,
.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-accent);
  transition: width var(--transition);
}

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

.nav-menu li a:hover::after,
.nav-menu li a.active::after,
.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

/* Also style .nav-links when inside .navbar (ul variant) */
.navbar .nav-links {
  list-style: none;
  margin: 0;
  padding: 0;
}

.navbar .nav-links li a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  position: relative;
  padding: 0.25rem 0;
  transition: color var(--transition);
  text-decoration: none;
}

.navbar .nav-links li a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-accent);
  transition: width var(--transition);
}

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

.navbar .nav-links li a:hover::after,
.navbar .nav-links li a.active::after {
  width: 100%;
}

/* --- Sections --- */
section {
  padding: 5rem 2rem;
}

.section-dark {
  background-color: var(--color-bg-dark);
}

.section-alt {
  background-color: var(--color-bg-alt);
}

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-heading {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-text-heading);
  margin-bottom: 2.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.section-heading::before {
  content: attr(data-number);
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--color-accent);
}

.section-heading::after {
  content: '';
  flex: 1;
  height: 1px;
  background-color: var(--color-border);
  max-width: 300px;
}

/* --- Hero Section --- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--nav-height);
  background-color: var(--color-bg-dark);
}

.hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  width: 100%;
  padding: 0 2rem;
}

.hero-greeting {
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--color-accent);
  margin-bottom: 1.25rem;
  font-weight: 400;
}

.hero-name {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 700;
  color: var(--color-text-heading);
  line-height: 1.1;
  margin-bottom: 0.5rem;
}

.hero-title {
  font-size: clamp(1.25rem, 3vw, 2rem);
  color: var(--color-text-muted);
  font-weight: 400;
  line-height: 1.3;
  margin-bottom: 1.5rem;
}

.hero-subtitle {
  max-width: 540px;
  color: var(--color-text-muted);
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: 2.5rem;
}

.hero-cta {
  display: inline-block;
  border: 1px solid var(--color-accent);
  color: var(--color-accent);
  padding: 0.85rem 2rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  border-radius: 4px;
  transition: background-color var(--transition), color var(--transition);
}

.hero-cta:hover {
  background-color: rgba(37, 99, 235, 0.08);
  color: var(--color-accent);
}

/* --- About Section --- */
.about-content {
  display: grid;
  grid-template-columns: 3fr 2fr;
  gap: 3rem;
  align-items: start;
}

.about-text p {
  margin-bottom: 1rem;
  color: var(--color-text-muted);
}

.about-text strong {
  color: var(--color-text-primary);
}

.about-interests {
  background-color: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1.75rem;
}

.about-interests h3 {
  font-size: 1rem;
  color: var(--color-text-heading);
  margin-bottom: 1rem;
  font-family: var(--font-mono);
  font-weight: 500;
}

.interest-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.interest-tag {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-accent);
  background-color: rgba(37, 99, 235, 0.06);
  padding: 0.35rem 0.85rem;
  border-radius: 20px;
  border: 1px solid rgba(37, 99, 235, 0.15);
  transition: background-color var(--transition), border-color var(--transition);
}

.interest-tag:hover {
  background-color: rgba(37, 99, 235, 0.12);
  border-color: rgba(37, 99, 235, 0.3);
}

/* --- Research Cards --- */
.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}

.research-card {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 2rem 1.75rem;
  transition: transform var(--transition), border-color var(--transition),
    box-shadow var(--transition);
  position: relative;
  box-shadow: 0 1px 3px var(--color-shadow);
}

.research-card:hover {
  transform: translateY(-5px);
  border-color: var(--color-accent);
  box-shadow: 0 10px 30px -15px rgba(0, 0, 0, 0.15);
}

.research-card-icon {
  font-size: 2rem;
  margin-bottom: 1.25rem;
  display: block;
}

.research-card h3 {
  font-size: 1.1rem;
  color: var(--color-text-heading);
  margin-bottom: 0.75rem;
  font-weight: 600;
}

.research-card p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* --- News / Timeline --- */
.news-timeline {
  position: relative;
  padding-left: 2rem;
}

.news-timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(
    to bottom,
    var(--color-accent),
    var(--color-border)
  );
}

.news-year {
  margin-bottom: 2.5rem;
}

.news-year-label {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-accent);
  margin-bottom: 1rem;
  position: relative;
}

.news-year-label::before {
  content: '';
  position: absolute;
  left: -2.35rem;
  top: 50%;
  transform: translateY(-50%);
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background-color: var(--color-accent);
  border: 3px solid var(--color-bg-dark);
  box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.3);
}

.news-item {
  padding: 0.6rem 0 0.6rem 0.75rem;
  border-left: 2px solid transparent;
  margin-bottom: 0.25rem;
  font-size: 0.95rem;
  color: var(--color-text-muted);
  transition: border-color var(--transition), color var(--transition);
}

.news-item:hover {
  border-left-color: var(--color-accent);
  color: var(--color-text-primary);
}

.news-item strong {
  color: var(--color-text-primary);
  font-weight: 600;
}

.news-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.15rem 0.5rem;
  border-radius: 3px;
  margin-right: 0.5rem;
  font-weight: 500;
}

.news-tag--paper {
  color: var(--color-accent);
  background-color: rgba(37, 99, 235, 0.08);
}

.news-tag--award {
  color: #b45309;
  background-color: rgba(180, 83, 9, 0.08);
}

.news-tag--milestone {
  color: #be185d;
  background-color: rgba(190, 24, 93, 0.08);
}

.news-tag--grant {
  color: #059669;
  background-color: rgba(5, 150, 105, 0.08);
}

/* --- Contact Section --- */
.contact-content {
  text-align: center;
  max-width: 600px;
  margin: 0 auto;
}

.contact-content p {
  color: var(--color-text-muted);
  margin-bottom: 2rem;
  font-size: 1.05rem;
}

.contact-details {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 2rem;
}

.contact-item {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.contact-item a {
  color: var(--color-accent);
}

.contact-cta {
  display: inline-block;
  border: 1px solid var(--color-accent);
  color: var(--color-accent);
  padding: 0.85rem 2.5rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  border-radius: 4px;
  transition: background-color var(--transition);
}

.contact-cta:hover {
  background-color: rgba(37, 99, 235, 0.08);
}

/* --- Footer --- */
.footer {
  background-color: var(--color-bg-dark);
  border-top: 1px solid var(--color-border);
  padding: 2rem;
  text-align: center;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-bottom: 1.25rem;
}

.footer-links a {
  color: var(--color-text-muted);
  font-size: 0.85rem;
  transition: color var(--transition), transform var(--transition);
  display: inline-block;
}

.footer-links a:hover {
  color: var(--color-accent);
  transform: translateY(-3px);
}

.footer-credit {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

/* --- Container (used by publications, cv pages) --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
  padding-top: calc(var(--nav-height) + 2rem);
}

/* --- Publication Page Styles --- */
.pub-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.pub-item {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1.5rem 1.75rem;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.pub-item:hover {
  border-color: var(--color-accent);
  box-shadow: 0 4px 20px -10px rgba(0, 0, 0, 0.12);
}

.pub-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-text-heading);
  margin-bottom: 0.5rem;
}

.pub-authors {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: 0.35rem;
}

.pub-venue {
  font-size: 0.85rem;
  font-style: italic;
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
}

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

.pub-link {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-accent);
  border: 1px solid var(--color-accent);
  padding: 0.25rem 0.65rem;
  border-radius: 3px;
  transition: background-color var(--transition);
}

.pub-link:hover {
  background-color: rgba(37, 99, 235, 0.08);
}

.pub-year-heading {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  color: var(--color-accent);
  margin-top: 2rem;
  margin-bottom: 1.25rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-border);
}

/* --- Teaching Page Styles --- */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
}

.course-card {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1.75rem;
  transition: transform var(--transition), border-color var(--transition),
    box-shadow var(--transition);
}

.course-card:hover {
  transform: translateY(-3px);
  border-color: var(--color-accent);
  box-shadow: 0 8px 25px -12px rgba(0, 0, 0, 0.12);
}

.course-code {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-accent);
  margin-bottom: 0.5rem;
  display: block;
}

.course-card h3 {
  font-size: 1.1rem;
  color: var(--color-text-heading);
  margin-bottom: 0.75rem;
}

.course-card p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

.course-terms {
  margin-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.course-term {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--color-text-muted);
  background-color: rgba(107, 114, 128, 0.08);
  padding: 0.2rem 0.5rem;
  border-radius: 3px;
}

/* --- CV Page Styles --- */
.cv-section {
  margin-bottom: 3rem;
}

.cv-section h3 {
  font-size: 1.25rem;
  color: var(--color-text-heading);
  margin-bottom: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-border);
}

.cv-entry {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}

.cv-entry:last-child {
  border-bottom: none;
}

.cv-date {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--color-accent);
  padding-top: 0.15rem;
}

.cv-details h4 {
  font-size: 1rem;
  color: var(--color-text-heading);
  margin-bottom: 0.25rem;
}

.cv-details p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.cv-download-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  border: 1px solid var(--color-accent);
  color: var(--color-accent);
  padding: 0.75rem 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  border-radius: 4px;
  margin-bottom: 2.5rem;
  transition: background-color var(--transition);
}

.cv-download-btn:hover {
  background-color: rgba(37, 99, 235, 0.08);
}

/* --- Lab Page Styles --- */
.lab-hero {
  text-align: center;
  margin-bottom: 3rem;
}

.lab-hero h2 {
  font-size: 2rem;
  color: var(--color-text-heading);
  margin-bottom: 0.75rem;
}

.lab-hero p {
  color: var(--color-text-muted);
  max-width: 650px;
  margin: 0 auto;
  font-size: 1.05rem;
}

.member-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
}

.member-card {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1.75rem;
  text-align: center;
  transition: transform var(--transition), border-color var(--transition);
}

.member-card:hover {
  transform: translateY(-3px);
  border-color: var(--color-accent);
}

.member-avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background-color: #f3f4f6;
  border: 2px solid var(--color-border);
  margin: 0 auto 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  color: var(--color-accent);
}

.member-card h3 {
  font-size: 1.05rem;
  color: var(--color-text-heading);
  margin-bottom: 0.25rem;
}

.member-role {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-accent);
  margin-bottom: 0.5rem;
}

.member-card p {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* --- Page Header (for non-home pages) --- */
.page-header {
  padding-top: calc(var(--nav-height) + 3rem);
  padding-bottom: 2rem;
  background-color: var(--color-bg-dark);
}

.page-header .section-inner {
  padding: 0 2rem;
}

/* --- Responsive Design --- */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background-color: rgba(255, 255, 255, 0.98);
    flex-direction: column;
    padding: 2rem;
    gap: 1.25rem;
    border-bottom: 1px solid var(--color-border);
  }

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

  .nav-toggle {
    display: flex;
  }

  .hero {
    min-height: auto;
    padding-top: calc(var(--nav-height) + 3rem);
    padding-bottom: 3rem;
  }

  .hero-name {
    font-size: 2.25rem;
  }

  section {
    padding: 3.5rem 1.25rem;
  }

  .about-content {
    grid-template-columns: 1fr;
  }

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

  .cv-entry {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }

  .section-heading {
    font-size: 1.4rem;
  }

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

  .member-grid {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  }
}

@media (max-width: 480px) {
  .nav-inner {
    padding: 0 1rem;
  }

  .hero-inner {
    padding: 0 1rem;
  }

  .footer-links {
    flex-direction: column;
    gap: 1rem;
  }
}