:root {
  --primary-color: #2c3e50;
  --secondary-color: #3498db;
  --accent-color: #488AC7;
  --text-color: #333;
  --light-bg: #f8f9fa;
  --white: #ffffff;
  --gray-border: #e0e0e0;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.1);
  --transition: all 0.3s ease;
}

* {
  scroll-behavior: smooth;
}

body {
  font-family: 'Roboto', sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-color);
  background-color: var(--light-bg);
}

.w3-montserrat {
  font-family: 'Montserrat', sans-serif;
  font-weight: 600;
}

/* Modern Navigation */
.w3-top {
  box-shadow: var(--shadow-sm);
  z-index: 1000;
}

.w3-bar {
  padding: 0 2rem !important;
  height: 60px;
  display: flex;
  align-items: center;
}

.w3-bar-item {
  transition: var(--transition) !important;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.5px;
  color: white !important;
}

.w3-bar-item:hover {
  background-color: var(--secondary-color) !important;
  transform: translateY(-2px);
  color: white !important;
}

/* Content sections with modern cards */
.w3-content {
  background: var(--white);
  border-radius: 8px;
  box-shadow: var(--shadow-sm);
  margin-bottom: 2rem;
  padding: 2rem;
}

/* Hero section */
#intro {
  padding: 3rem 2rem !important;
}

#intro h1 {
  font-size: 2.5rem;
  margin-bottom: 2rem;
  color: var(--primary-color);
  letter-spacing: 1px;
}

#intro img {
  border-radius: 50% !important;
  box-shadow: var(--shadow-md);
  transition: var(--transition);
}

#intro img:hover {
  transform: scale(1.05);
  box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}

#intro p {
  font-size: 1.05rem;
  margin-bottom: 1.5rem;
  text-align: justify;
}

#intro a {
  color: var(--secondary-color);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: var(--transition);
}

#intro a:hover {
  border-bottom-color: var(--secondary-color);
}

/* Section headers */
.w3-wide {
  font-size: 2rem;
  margin-bottom: 2rem;
  position: relative;
  padding-bottom: 1rem;
}

.w3-wide::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 4px;
  background: linear-gradient(90deg, var(--accent-color), var(--secondary-color));
  border-radius: 2px;
}

h3 {
  color: var(--primary-color);
  font-size: 1.5rem;
  margin: 2rem 0 1rem 0;
  padding-left: 1rem;
  border-left: 4px solid var(--accent-color);
}

/* Lists */
ol, ul {
  padding-left: 20px;
}

li {
  margin: 1.2rem 0;
  line-height: 1.8;
}

li b {
  color: var(--primary-color);
}

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

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

/* Social Links */
.social-links {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin: 1rem 0 2rem 0;
  flex-wrap: wrap;
}

.social-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0;
  background: transparent;
  color: var(--text-color) !important;
  text-decoration: none;
  font-weight: 400;
  font-size: 0.9rem;
  transition: var(--transition);
  opacity: 0.7;
}

.social-link:hover {
  opacity: 1;
  color: var(--secondary-color) !important;
}

.social-link i {
  font-size: 1.1rem;
}

.social-link.linkedin:hover {
  color: #0077b5 !important;
}

.social-link.scholar:hover {
  color: #4285f4 !important;
}

.social-link.researchgate:hover {
  color: rgb(0, 204, 187) !important;
}

/* Icons */
.fa, .fab, .ai {
  transition: var(--transition);
}

.fa-researchgate:hover {
  color: rgb(0, 204, 187);
  transform: scale(1.2);
}

.fa-youtube:hover {
  color: #FF0000;
  transform: scale(1.2);
}

.ai-arxiv:hover {
  color: #B31B1B;
  transform: scale(1.2);
}

/* Contact section */
#contact a {
  color: var(--secondary-color);
  text-decoration: none;
  transition: var(--transition);
}

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

#contact i {
  color: var(--accent-color);
}

/* Responsive improvements */
@media (max-width: 768px) {
  .w3-content {
    padding: 1.5rem;
    margin: 1rem;
  }

  #intro h1 {
    font-size: 2rem;
  }

  .w3-wide {
    font-size: 1.75rem;
  }

  h3 {
    font-size: 1.3rem;
  }

  #intro .w3-third {
    text-align: center;
  }

  #intro .w3-col {
    width: 100%;
    display: block;
  }

  #intro img {
    width: 50% !important;
    margin: 0 auto 2rem auto !important;
    float: none !important;
    display: block;
  }

  .social-links {
    gap: 0.8rem;
    font-size: 0.85rem;
  }
}

@media (max-width: 480px) {
  body {
    font-size: 15px;
  }

  #intro h1 {
    font-size: 1.75rem;
  }

  #intro img {
    width: 60% !important;
  }

  li {
    font-size: 0.95rem;
  }
}

/* Smooth animations */
.w3-container {
  animation: fadeIn 0.5s ease-in;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Better spacing for sections */
.w3-white {
  background-color: var(--white) !important;
  margin-bottom: 0;
}

.w3-white > .w3-container {
  padding: 3rem 2rem;
}

/* Improve readability */
.w3-justify {
  text-align: justify;
}

.mySlides {
  display: none;
}

/* Publications Toggle Feature */
.publications-toggle {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin: 1rem auto 2rem auto;
}

.tab-button {
  background: transparent;
  border: 2px solid var(--gray-border);
  color: var(--text-color);
  padding: 0.7rem 2rem;
  font-family: 'Montserrat', sans-serif;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  border-radius: 8px;
  transition: var(--transition);
}

.tab-button:hover {
  border-color: var(--accent-color);
  color: var(--accent-color);
  transform: translateY(-2px);
}

.tab-button.active {
  background: linear-gradient(135deg, var(--accent-color), var(--secondary-color));
  color: white;
  border-color: transparent;
  box-shadow: var(--shadow-md);
}

/* Type badges for publications */
.pub-type-badge {
  display: inline-block;
  color: white;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  margin-right: 0.5rem;
  letter-spacing: 0.5px;
  vertical-align: middle;
}

.pub-journal { background: var(--accent-color); }
.pub-conference { background: var(--secondary-color); }
.pub-workshop { background: #27ae60; }
.pub-book-chapter { background: #8e44ad; }

/* Year sections in by-year view */
#view-by-year h3 {
  margin-top: 2rem;
}

#view-by-year h3:first-child {
  margin-top: 0;
}

/* Mobile responsive for toggle */
@media (max-width: 480px) {
  .tab-button {
    padding: 0.6rem 1.2rem;
    font-size: 0.85rem;
  }
}