/* ===== Base Styles ===== */
:root {
  --color-text: #000000;
  --color-text-light: #555555;
  --color-background: #ffffff;
  --color-surface: #fafafa;
  --color-border: #e5e5e5;
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --max-width: 900px;
  --spacing: 1.5rem;
  --transition: 0.2s ease;
  --color-tag-background: #000000;
  --color-tag-text: #ffffff;
}

[data-theme="dark"] {
  --color-text: #ffffff;
  --color-text-light: #a0a0a0;
  --color-background: #0a0a0a;
  --color-surface: #141414;
  --color-border: #2a2a2a;
  --color-tag-background: #ffffff;
  --color-tag-text: #000000;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background-color: var(--color-background);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color var(--transition), color var(--transition);
}

main {
  flex: 1;
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--spacing);
  padding-top: 3rem;
}

a {
  color: var(--color-text);
  text-decoration: underline;
  text-underline-offset: 3px;
}

a:hover {
  text-decoration: none;
}

img {
  max-width: 100%;
  height: auto;
}

em { 
  font-family: "Instrument Serif", serif;
  font-weight: 400;
  font-style: italic;
}

/* ===== Header ===== */
.site-header {
  background: var(--color-background);
  padding: 1.25rem var(--spacing);
  transition: background-color var(--transition);
}

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

.logo {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text);
  text-decoration: none;
  display: flex;
  align-items: center;
}

.logo:hover {
  opacity: 0.7;
}

.logo img {
  height: 32px;
  width: auto;
}

/* Light mode: show light logo, hide dark logo */
.logo-dark {
  display: none;
}

.logo-light {
  display: block;
}

/* Dark mode: show dark logo, hide light logo */
[data-theme="dark"] .logo-light {
  display: none;
}

[data-theme="dark"] .logo-dark {
  display: block;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 1.75rem;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 1.75rem;
}

.nav-links a {
  color: var(--color-text);
  font-size: 0.9rem;
  text-decoration: none;
  transition: opacity var(--transition);
}

.nav-links a:hover {
  opacity: 0.6;
}

.nav-links a.active {
  opacity: 1;
}

/* ===== Theme Toggle ===== */
.theme-toggle {
  background: none;
  border: none;
  padding: 0.25rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity var(--transition);
}

.theme-toggle:hover {
  opacity: 0.6;
}

.theme-toggle i {
  font-size: 1.125rem;
  color: var(--color-text);
}

/* Light mode: show sun, hide moon */
.theme-toggle .icon-moon {
  display: none;
}

.theme-toggle .icon-sun {
  display: block;
}

/* Dark mode: show moon, hide sun */
[data-theme="dark"] .theme-toggle .icon-sun {
  display: none;
}

[data-theme="dark"] .theme-toggle .icon-moon {
  display: block;
}

/* ===== Academic Hero ===== */
.hero-academic {
  padding: 2rem 0 2rem;
}

.hero-academic h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
  letter-spacing: -0.02em;
}

.subtitle {
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--color-text);
  margin-bottom: 1.25rem;
}

.social-icons {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.social-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  transition: opacity var(--transition);
}

.social-icon:hover {
  opacity: 0.5;
}

.social-icon i {
  font-size: 1.25rem;
  color: var(--color-text);
}

.hero-image {
  margin-bottom: 1.5rem;
}

.hero-image img {
  width: 120px;
  height: 120px;
  object-fit: cover;
  border-radius: 50%;
  transition: filter var(--transition);
}

.hero-image img:hover {
  filter: grayscale(100%);
}

.header-icon {
  padding-bottom: 2%;
}

/* ===== Bio Section ===== */
.bio {
  padding: 1rem 0 2rem;
}

.bio p {
  font-size: 1rem;
  line-height: 1.75;
  color: var(--color-text);
  margin-bottom: 1rem;
}

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

.pronoun {
  font-family: "Instrument Serif", serif;
  letter-spacing: 1px;
  font-size: smaller;
}

/* ===== Footer ===== */
.site-footer {
  background: var(--color-background);
  padding: 2rem var(--spacing);
  margin-top: 4rem;
  transition: background-color var(--transition), border-color var(--transition);
}

.footer-content {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-content p {
  color: var(--color-text);
  font-size: 0.875rem;
}

.social-links {
  display: flex;
  gap: 1.5rem;
}

.social-links a {
  color: var(--color-text);
  font-size: 0.875rem;
}

/* ===== Page Content ===== */
.page-content {
  padding: 2rem 0;
}

.page-content h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

.page-content h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
}

.page-content h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

.page-content h5 {
  font-size: 0.8
  rem;
  font-weight: 600;
  margin-top: 1rem;
  margin-bottom: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  border-bottom: 1px solid var(--color-text);
}

.page-intro {
  font-size: 1rem;
  color: var(--color-text-light);
  margin-bottom: 2rem;
}

/* ===== Project Grid ===== */
.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1px;
  background: var(--color-border);
  border: 1px solid var(--color-border);
}

.project-card {
  background: var(--color-background);
  padding: 1.5rem;
  transition: background-color var(--transition);
}

.project-card:hover {
  background: var(--color-surface);
}

.project-card h2,
.project-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.project-card h2 a,
.project-card h3 a {
  color: var(--color-text);
  text-decoration: none;
}

.project-card h2 a:hover,
.project-card h3 a:hover {
  text-decoration: underline;
}

.project-card p {
  color: var(--color-text-light);
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

.project-date {
  font-size: 0.8rem;
  color: var(--color-text-light);
}

/* ===== Tags ===== */
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.tag {
  background: var(--color-tag-background);
  color: var(--color-tag-text);
  padding: 0.2rem 0.6rem;
  border: none;
  font-size: 0.7rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-radius: 4px;
}

/* ===== About Page ===== */
.about-intro {
  font-size: 1rem;
  margin-bottom: 2rem;
}

.skills-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.skills-list li {
  background: transparent;
  padding: 0.4rem 0.8rem;
  border: 1px solid var(--color-border);
  font-size: 0.875rem;
}

.experience-item,
.education-item {
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}

.experience-item:last-child,
.education-item:last-child {
  border-bottom: none;
}

.company,
.institution {
  color: var(--color-text-light);
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}

/* ===== Contact Page ===== */
.contact-info {
  margin-top: 2rem;
}

.contact-method {
  margin-bottom: 2rem;
}

.social-list {
  list-style: none;
  display: flex;
  gap: 1.5rem;
}

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  font-size: 0.9rem;
  font-weight: 500;
  text-decoration: none;
  transition: all var(--transition);
}

.btn-primary {
  background: var(--color-text);
  color: var(--color-background);
  border: 1px solid var(--color-text);
}

.btn-primary:hover {
  background: transparent;
  color: var(--color-text);
}

.btn-secondary {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  border-color: var(--color-text);
}

/* ===== Publications Page ===== */
.publications-list {
  margin-top: 2rem;
}

.publication-item {
  margin-bottom: 2rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--color-border);
}

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

.publication-item h2 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.publication-authors {
  color: var(--color-text);
  font-size: 0.9rem;
  margin-bottom: 0.25rem;
}

.publication-venue {
  color: var(--color-text-light);
  font-size: 0.875rem;
  margin-bottom: 0.75rem;
}

.publication-links {
  display: flex;
  gap: 1rem;
}

.publication-links a {
  font-size: 0.875rem;
}

/* ===== Thoughts Page ===== */
.thoughts-list {
  margin-top: 2rem;
}

.thought-item {
  margin-bottom: 2rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--color-border);
}

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

.thought-item h2 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.thought-item h2 a {
  text-decoration: none;
}

.thought-item h2 a:hover {
  text-decoration: underline;
}

.thought-date {
  color: var(--color-text-light);
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}

.thought-item p {
  color: var(--color-text-light);
  font-size: 0.9rem;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav-container {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
  }

  .logo {
    text-align: left;
  }

  .nav-right {
    width: 100%;
    justify-content: space-between;
  }

  .nav-links {
    gap: 1rem;
  }

  .hero-image img {
    width: 100px;
    height: 100px;
  }

  .hero-academic h1 {
    font-size: 2rem;
  }

  .footer-content {
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
  }
  .social-links {
    justify-content: flex-start;
  }
}