/* @import url('https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,100..900;1,100..900&display=swap'); */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --primary-color: #2563eb;
  --secondary-color: #1e40af;
  --text-dark: #1f2937;
  --text-light: #6b7280;
  --bg-light: #f9fafb;
  --bg-white: #ffffff;
  --accent-color: #10b981;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}


body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  line-height: 1.6;
  color: var(--text-dark);
  overflow-x: hidden;
}

.sidebar {
  background: #171b26;
  /* background-color: #660000; */
  color: #fff;
  width: 280px;
  height: 100vh;
  position: fixed;
  transition: left 0.3s;
  left: 0;
  top: 0;
  z-index: 100;
  overflow-y: auto;
}

.sidebar-header {
  text-align: center;
  background: linear-gradient(135deg, rgba(52, 152, 219, 0.2) 0%, rgba(46, 204, 113, 0.2) 100%);
  padding: 32px 8px 18px 8px;
  border-bottom: 1px solid #232537;
}

.profile-img {
  width: 96px;
  height: 96px;
  object-fit: cover;
  border-radius: 50%;
  margin-bottom: 12px;
  border: 2px solid #aaaaaa;
  box-shadow: 0 4px 16px rgba(34, 139, 34, 0.03);
  transition: box-shadow 0.3s;
}

.sidebar-header h2 {
  font-size: 1.3rem;
  margin: 0;
  font-weight: 600;
}

.sidebar-header p {
  font-size: 0.93rem;
  color: #a8b2d1;
}

.social-icons {
  margin-top: 22px;
  display: flex;
  justify-content: center;
  gap: 20px;
}

.social-icons img {
  width: 23px;
  height: 23px;
  filter: invert(1);
  opacity: 0.82;
  transition: opacity 0.2s;
}

.social-icons img:hover {
  opacity: 1;
}

.nav-links {
  list-style: none;
  /* margin-top: 16px; */
  padding-left: 0;
}

.nav-links li {
  margin: 0;
}

.nav-links li a {
  display: block;
  text-decoration: none;
  color: #ccd6f6;
  padding: 15px 28px;
  transition: background 0.2s;
  font-size: 1.05rem;
  letter-spacing: 0.01em;
}


.nav-links li a:hover {
  background: #4a5568;
  color: white;
}

.icon {
  margin-right: 15px;
  padding-right: 5px;
}

.publication-icon {
  margin-right: 25px;
}

.edu-icon {
  margin-right: 16px;
}

/* main content */
.main-content {
  margin-left: 280px;
  padding: 20px;
  transition: margin-left 0.3s;
}

.container {
  /* max-width: 1200px; */
  margin: 0 auto;
}

/* research section */
#research {
  background: var(--bg-white);
}

.research-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 3rem;
  margin-top: 3rem;
}

.research-item {
  text-align: center;
  padding: 2rem;
  border-radius: 12px;
  transition: all 0.3s ease;
}

.research-item:hover {
  background: var(--bg-light);
  transform: translateY(-5px);
}

.research-icon {
  font-size: 2rem;
  color: var(--primary-color);
  margin-bottom: 1rem;
}

.research-item h3 {
  font-size: 1.3rem;
  margin-bottom: 1rem;
  color: #2d3748;
}

.research-item p {
  color: var(--text-light);
  line-height: 1.8;
}


/* content section */
.content-section {
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 2px 12px rgba(33, 40, 60, 0.07);
  padding: 16px 28px;
  margin-top: 20px;
}


.content-section h2 {
  font-size: 1.5rem;
  color: #2d3148;
  margin-bottom: 18px;
  letter-spacing: 0.04em;
}

.content-section p {
  font-size: 1.1rem;
  margin-bottom: 10px;
  padding-right: 25px;
  text-align: justify;
  line-height: 1.55;
}

.list-item {
  list-style-type: square;
  margin-left: 20px;
}

.call-to-action {
  background: linear-gradient(90deg, #e0e0e0 60%, #eaf4ec 100%);
  padding: 20px;
  margin-top: 14px;
  margin-bottom: 14px;
  color: #333;
  border-radius: 7px;
  box-shadow: 0 2px 12px rgba(34, 139, 34, 0.07);
}

.call-to-action h4 {
  font-size: 20px;
}

.more-about-me {
  margin-top: 15px;
}

.btn {
  padding: 0.75rem 1rem;
  border: none;
  border-radius: 25px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  text-decoration: none;
  display: inline-block;
}

.btn-primary {
  background: var(--primary-color);
  color: white;
}

.btn-primary:hover {
  background: var(--secondary-color);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
  background: var(--primary-color);
  color: white;
  transform: translateY(-2px);
}


/* More about me */
/* More About Me Section */
.margin {
  margin-top: 50px;
}

.more-about {
  background: linear-gradient(135deg, rgba(26, 35, 126, 0.05) 0%, rgba(57, 73, 171, 0.1) 100%);
  border-radius: 20px;
  padding: 60px 40px;
  position: relative;
  overflow: hidden;
}

.more-about::before {
  content: '';
  position: absolute;
  top: -50px;
  right: -50px;
  width: 300px;
  height: 300px;
  border-radius: 50%;
  background: rgba(0, 172, 193, 0.1);
  z-index: 0;
}

.more-about::after {
  content: '';
  position: absolute;
  bottom: -50px;
  left: -50px;
  width: 250px;
  height: 250px;
  border-radius: 50%;
  background: rgba(0, 200, 83, 0.1);
  z-index: 0;
}

.more-about-content {
  position: relative;
  z-index: 1;
}

.more-about-text {
  animation: fadeInUp 1s ease-out;
}

.more-about-text h2 {
  font-family: 'Montserrat', sans-serif;
  font-size: 1.5rem;
  color: #2d3748;
  margin-bottom: 30px;
  position: relative;
  display: inline-block;
}

.more-about-text h2::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 0;
  width: 80px;
  height: 4px;
  background: var(--gradient-accent);
  border-radius: 2px;
}

.more-about-text p {
  font-size: 1.1rem;
  line-height: 1.8;
  margin-bottom: 25px;
  color: var(--text-color);
}

.interests-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
  margin: 40px 0;
}

.interest-card {
  background: white;
  border-radius: 15px;
  padding: 25px;
  text-align: center;
  box-shadow: var(--card-shadow);
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.interest-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--gradient-accent);
}

.interest-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--hover-shadow);
}

.interest-icon {
  font-size: 2rem;
  color: var(--accent-color);
  margin-bottom: 15px;
}

.interest-card h3 {
  font-family: 'Montserrat', sans-serif;
  font-size: 1.2rem;
  color: #2d3748;
  margin-bottom: 10px;
}

.interest-card p {
  font-size: 0.95rem;
  color: var(--text-color);
  margin-bottom: 0;
}

.f1-section {
  background: linear-gradient(135deg, rgba(255, 0, 0, 0.05) 0%, rgba(255, 0, 0, 0.1) 100%);
  border-radius: 20px;
  padding: 40px;
  margin: 40px 0;
  position: relative;
  overflow: hidden;
}

.f1-section::before {
  content: '';
  position: absolute;
  top: -30px;
  right: -30px;
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background: rgba(255, 0, 0, 0.1);
  z-index: 0;
}

.f1-content {
  position: relative;
  z-index: 1;
}

.f1-header {
  display: flex;
  align-items: center;
  margin-bottom: 25px;
}

.f1-icon {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  background: linear-gradient(135deg, #e10600 0%, #ff4d4d 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.8rem;
  margin-right: 20px;
  box-shadow: 0 5px 15px rgba(225, 6, 0, 0.3);
}

.f1-header h3 {
  font-family: 'Montserrat', sans-serif;
  font-size: 1.5rem;
  color: #e10600;
  font-weight: 600;
}

.f1-content p {
  font-size: 1.1rem;
  line-height: 1.8;
  margin-bottom: 20px;
  color: var(--text-color);
}

.f1-keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 15px;
  margin-top: 25px;
}

.f1-keyword {
  background: white;
  color: #e10600;
  padding: 8px 16px;
  border-radius: 25px;
  font-weight: 600;
  font-size: 0.9rem;
  box-shadow: var(--card-shadow);
  transition: all 0.3s ease;
}

.f1-keyword:hover {
  transform: translateY(-3px);
  box-shadow: var(--hover-shadow);
}

.cv-download {
  margin-top: 50px;
  text-align: center;
}

.cv-download .btn {
  background-color: #2d3748;
  color: white;
  font-size: 1.2rem;
  padding: 15px 40px;
  box-shadow: 0 8px 20px rgba(26, 35, 126, 0.3);
  position: relative;
  overflow: hidden;
}

.cv-download .btn:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 25px rgba(26, 35, 126, 0.4);
}

.cv-download .btn i {
  margin-left: 10px;
}

.footer {
  background: linear-gradient(135deg, #1a2b3d 0%, #2c3e50 100%);
  color: var(--white);
  padding: 40px 0 20px;
  margin-top: 50px;
  position: relative;
  overflow: hidden;
}

.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 5px;
  background: linear-gradient(90deg,#3498db, #2ecc71, #9b59b6);
}

.footer-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 30px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.footer-copyright {
  text-align: center;
  padding-top: 20px;
  width: 100%;
  color: rgba(255, 255, 255, 0.7);
  font-size: 14px;
}

.footer-copyright p {
  margin-bottom: 5px;
}

.footer-copyright a {
  color: #3498db;
  text-decoration: none;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.footer-copyright a:hover {
  color: #ffffff;
}

.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background:#3498db;
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  z-index: 99;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);;
}


.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  transform: translateY(-5px);
}

/* Responsive design */
@media (max-width: 955px) {
  .main-content {
    margin-left: 0;
  }

  .sidebar {
    left: -290px;
    width: 250px;
  }

  .sidebar.open {
    left: 0;
  }
}

/* Toggle button (hamburger) */
.toggle-btn {
  display: none;
  position: fixed;
  top: 22px;
  left: 20px;
  z-index: 200;
  background: #171b26;
  border: none;
  color: #fff;
  font-size: 2rem;
  padding: 5px 14px 5px 10px;
  border-radius: 6px;
  box-shadow: 0 2px 10px rgba(25, 30, 40, 0.13);
  cursor: pointer;
  transition: background 0.2s;
}

.toggle-btn:active,
.toggle-btn:focus {
  background: #232537;
}

@media (max-width: 955px) {
  .toggle-btn {
    display: block;
  }
}

/* Keep sidebar above overlay */
@media (max-width: 955px) {
  .sidebar {
    top: 0;
    left: -260px;
    height: 100vh;
    box-shadow: 2px 0 8px rgba(25, 35, 45, 0.06);
    transition: left 0.3s;
  }

  .sidebar.open {
    left: 0;
  }

  .more-about-text h2 {
    font-size: 2rem;
  }

  .more-about {
    padding: 40px 20px;
  }

  .interests-grid {
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  }

  .cta-buttons {
    justify-content: center;
  }

  .vision-cards {
    grid-template-columns: 1fr;
  }

  .education-timeline {
    padding-left: 30px;
  }

  .timeline-item {
    padding: 20px 30px 20px 40px;
  }

  .timeline-item::before {
    left: -46px;
    width: 25px;
    height: 25px;
  }

  .f1-header {
    flex-direction: column;
    text-align: center;
  }

  .f1-icon {
    margin-right: 0;
    margin-bottom: 15px;
  }

}

@media (max-width: 600px) {
  .sidebar-header {
    padding: 20px 4px 10px 4px;
  }

  .main-content {
    padding: 22px 2vw;
  }

  .container {
    padding: 15px;
  }

  .content-section {
    padding: 16px 8px;
  }

  .profile-img {
    width: 74px;
    height: 74px;
  }

  .section-title {
    font-size: 1.8rem;
  }

  .more-about-text h2 {
    font-size: 1.8rem;
  }

  .btn {
    padding: 12px 25px;
    font-size: 1rem;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 45px;
    height: 45px;
  }

  .interests-grid {
    grid-template-columns: 1fr;
  }
}
html{
  scroll-behavior: smooth;
}