:root {
  /* Light Mode Colors */
  --bg-primary: #f4f7f6;
  --bg-secondary: #ffffff;
  --text-primary: #1a1a2e;
  --text-secondary: #4a4a68;
  --accent-primary: #007bff;
  --accent-color: var(--accent-primary); /* Backward compatibility */
  --accent-hover: #2980b9;

  /* Dark Mode Colors */
  --dark-bg-primary: #121212;
  --dark-bg-secondary: #1e1e1e;
  --dark-text-primary: #e0e0e0;
  --dark-text-secondary: #b0b0b0;
  --dark-accent-color: #4ecdc4;
  --dark-accent-hover: #45b7aa;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  transition: all 0.3s ease;
}

body {
  font-family: "Inter", sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
}

body.dark-mode {
  background-color: var(--dark-bg-primary);
  color: var(--dark-text-primary);
}

/* Skip Link Styling */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--accent-color);
  color: white;
  padding: 8px;
  text-decoration: none;
  border-radius: 4px;
  font-weight: 500;
  z-index: 9999;
  transition: top 0.3s cubic-bezier(0, 0, 0.2, 1);
}

.skip-link:focus {
  top: 6px;
}

/* Header Styles */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background-color: var(--bg-secondary);
  box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
  border-bottom: 1px solid #dee2e6;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
  background-color: rgba(255, 255, 255, 0.95);
  transition: all 0.3s cubic-bezier(0, 0, 0.2, 1);
}

.header.scrolled {
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  backdrop-filter: blur(20px);
}

.header.header-hidden {
  transform: translateY(-100%);
  transition: transform 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

.dark-mode .header {
  background-color: var(--dark-bg-secondary);
  box-shadow: 0 2px 10px rgba(255, 255, 255, 0.05);
}



.logo-container {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.logo {
  /* width: 60px; */
  height: 70px;
  margin-left: 10px;
  margin-top: 10px;
  margin-bottom: 10px;
  border-radius: 0%;
  object-fit: cover;
}

.vertical-line {
  width: 3px;
  height: 60px;
  background-color: #313131;
}

.lab-name {
  font-family: "Space Grotesk", sans-serif;
  font-size: 1.3rem;
  font-weight: 700;
}

.navigation ul {
  display: flex;
  list-style: none;
  gap: 2rem;
}

.nav-link {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  position: relative;
  padding-bottom: 0.3rem;
}

.nav-link::after {
  content: "";
  position: absolute;
  width: 0;
  height: 2px;
  bottom: 0;
  left: 0;
  background-color: var(--accent-color);
  transition: width 0.3s ease;
}

.nav-link:hover::after {
  width: 100%;
}

.dark-mode .nav-link {
  color: var(--dark-text-secondary);
}

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

.dark-mode .nav-link:hover {
  color: var(--dark-accent-color);
}

/* Publications Section */
.publications-section {
  padding: 2rem 5%;
  background-color: var(--bg-secondary);
}

.section-header {
  text-align: center;
  margin-bottom: 2rem;
  font-family: "Space Grotesk", sans-serif;
  color: var(--text-primary);
}

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

.publications-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  max-width: 1000px;
  margin: 0 auto;
}

.publication-item {
  display: flex;
  gap: 2rem;
  padding: 1.5rem;
  background-color: var(--bg-primary);
  border-radius: 10px;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
  transition: transform 0.3s ease;
}

.dark-mode .publication-item {
  background-color: var(--dark-bg-secondary);
}

.publication-item:hover {
  transform: translateX(10px);
}

.pub-year {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-color);
  min-width: 70px;
}

.dark-mode .pub-year {
  color: var(--dark-accent-color);
}

.pub-details h4 {
  margin-bottom: 0.5rem;
}

.pub-authors {
  color: var(--text-secondary);
  font-style: italic;
  margin-bottom: 0.3rem;
}

.dark-mode .pub-authors {
  color: var(--dark-text-secondary);
}

.pub-venue {
  font-weight: 500;
  margin-bottom: 0.5rem;
}

.pub-link {
  display: inline-block;
  color: var(--accent-color);
  font-weight: 600;
  text-decoration: none;
  position: relative;
}

.dark-mode .pub-link {
  color: var(--dark-accent-color);
}

.pub-link::after {
  content: "";
  position: absolute;
  bottom: -3px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent-color);
  transition: width 0.3s ease;
}

.dark-mode .pub-link::after {
  background-color: var(--dark-accent-color);
}

.pub-link:hover::after {
  width: 100%;
}

/* Footer */
.dark-mode .footer {
  background-color: var(--dark-bg-secondary);
}

.footer-button {
  text-decoration: none;
  color: white;
  padding: 0.5rem 1rem;
  border: 1px solid white;
  border-radius: 5px;
  transition: all 0.3s ease;
}

.footer-button:hover {
  background-color: rgba(255, 255, 255, 0.1);
}

.footer {
  background-color: var(--text-primary);
  color: white;
  padding: 3rem 5% 1rem;
}

.dark-mode .footer {
  background-color: var(--dark-bg-secondary);
}

.two-column-list {
  display: flex;
  gap: 2rem;
}

.two-column-list ul {
  padding-left: 0;
  margin-top: 0;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  margin-bottom: 2rem;
  flex-direction: row;
}

.footer-logo {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.footer-img {
  /* width: 100px; */
  height: 100px;
  border-radius: 10px;
  margin-bottom: 1rem;
  object-fit: cover;
}

.footer-logo p {
  font-size: 1.1rem;
  font-weight: 500;
}

.footer-links {
  flex: 2;
  display: flex;
  justify-content: space-between;
  gap: 2 rem;
}

.footer-col h4 {
  font-size: 1.2rem;
  margin-bottom: 1.2rem;
  position: relative;
}

.footer-col h4::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -8px;
  height: 2px;
  width: 40px;
  background-color: var(--accent-color);
}

.dark-mode .footer-col h4::after {
  background-color: var(--dark-accent-color);
}

.footer-col ul {
  list-style: none;
}

.footer-col ul li {
  margin-bottom: 0.8rem;
}

.footer-col ul li a {
  color: var(--dark-text-secondary);
  text-decoration: none;
  transition: all 0.3s ease;
}

.footer-col ul li a:hover {
  color: white;
  padding-left: 5px;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 1.5rem;
  text-align: center;
}

.university-affiliation {
  margin-top: 0.5rem;
  font-size: 0.9rem;
  color: var(--dark-text-secondary);
}

@media screen and (max-width: 768px) {
  .footer-content {
    flex-direction: column;
  }

  .footer-logo {
    margin-bottom: 2rem;
    align-items: center;
    text-align: center;
  }

  .footer-links {
    flex-direction: column;
    gap: 2rem;
  }

  .footer-col {
    text-align: center;
  }

  .footer-col h4::after {
    left: 50%;
    transform: translateX(-50%);
  }
}

/* Toggle Switch */
.theme-toggle {
  position: relative;
  width: 100px;
  height: 50px;
  --link: rgb(27, 129, 112);
  --link-hover: rgb(24, 94, 82);
}

.theme-switch-label {
  position: absolute;
  width: 100%;
  height: 50px;
  background-color: var(--dark-bg-primary);
  border-radius: 25px;
  cursor: pointer;
  border: 3px solid var(--dark-bg-primary);
}

.theme-switch {
  position: absolute;
  display: none;
}

.slider {
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 25px;
  -webkit-transition: 0.3s;
  transition: 0.3s;
}

.theme-switch:checked ~ .slider {
  background-color: var(--bg-primary);
}

.slider::before {
  content: "";
  position: absolute;
  top: 10px;
  left: 10px;
  width: 25px;
  height: 25px;
  border-radius: 50%;
  -webkit-box-shadow: inset 12px -4px 0px 0px var(--bg-primary);
  box-shadow: inset 12px -4px 0px 0px var(--bg-primary);
  background-color: var(--dark-bg-primary);
  -webkit-transition: 0.3s;
  transition: 0.3s;
}

.theme-switch:checked ~ .slider::before {
  -webkit-transform: translateX(50px);
  -ms-transform: translateX(50px);
  transform: translateX(50px);
  background-color: var(--dark-bg-primary);
  -webkit-box-shadow: none;
  box-shadow: none;
}

/* Responsive Design */
@media screen and (max-width: 768px) {
  .header,
  .hero-section,
  .about-content,
  .project-slider {
    flex-direction: column;
    text-align: center;
  }

  .footer-links {
    flex-direction: column;
    align-items: center;
  }
}

/* Toggle Switch */
.theme-toggle {
  position: relative;
  width: 100px;
  height: 50px;
  --link: rgb(27, 129, 112);
  --link-hover: rgb(24, 94, 82);
}

.theme-switch-label {
  position: absolute;
  width: 100%;
  height: 50px;
  background-color: var(--dark-bg-primary);
  border-radius: 25px;
  cursor: pointer;
  border: 3px solid var(--dark-bg-primary);
}

.theme-switch {
  position: absolute;
  display: none;
}

.slider {
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 25px;
  -webkit-transition: 0.3s;
  transition: 0.3s;
}

.theme-switch:checked ~ .slider {
  background-color: var(--bg-primary);
}

.slider::before {
  content: "";
  position: absolute;
  top: 10px;
  left: 10px;
  width: 25px;
  height: 25px;
  border-radius: 50%;
  -webkit-box-shadow: inset 12px -4px 0px 0px var(--bg-primary);
  box-shadow: inset 12px -4px 0px 0px var(--bg-primary);
  background-color: var(--dark-bg-primary);
  -webkit-transition: 0.3s;
  transition: 0.3s;
}

.theme-switch:checked ~ .slider::before {
  -webkit-transform: translateX(50px);
  -ms-transform: translateX(50px);
  transform: translateX(50px);
  background-color: var(--dark-bg-primary);
  -webkit-box-shadow: none;
  box-shadow: none;
}