/* ===== VARIABLES ===== */
:root {
  --primary-color: #8b5cf6; /* purple accent */
  --primary-light: rgba(139, 92, 246, 0.1);
  --bg-dark: #0e0a16;
  --bg-card: #1a1424;
  --bg-header: #1c1630;
  --bg-nav: #1e1833;
  --text-light: #fff;
  --text-muted: #c3b8d8;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.15);
  --transition: all 0.3s ease;
}

/* Light Theme Variables */
.light-theme {
  --bg-dark: #f8f6fb;
  --bg-card: #ffffff;
  --bg-header: #f1e9ff;
  --bg-nav: #ffffff;
  --text-light: #2e1e46;
  --text-muted: #6b5f7f;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.05);
}


/* ===== GLOBAL STYLES ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Inter', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: var(--bg-dark);
  color: var(--text-light);
  line-height: 1.7;
  transition: background-color 0.3s ease, color 0.3s ease;
  overflow-x: hidden;
}

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem;
}

section {
  padding: 6rem 0;
}

img {
  max-width: 100%;
}

a {
  text-decoration: none;
  color: var(--primary-color);
  transition: var(--transition);
  font-weight: 500;
}

a:hover {
  color: var(--text-light);
}

.btn {
  display: inline-block;
  background: var(--primary-color);
  color: #fff;
  padding: 0.8rem 1.8rem;
  border-radius: 6px;
  text-decoration: none;
  transition: var(--transition);
  border: 2px solid var(--primary-color);
  font-weight: 600;
  letter-spacing: 0.5px;
  box-shadow: 0 4px 12px rgba(0, 200, 150, 0.2);
}

.btn:hover {
  background: transparent;
  color: var(--primary-color);
  box-shadow: 0 6px 16px rgba(0, 200, 150, 0.3);
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: var(--primary-color);
  box-shadow: none;
}

.btn-outline:hover {
  background: var(--primary-color);
  color: #fff;
  box-shadow: 0 4px 12px rgba(0, 200, 150, 0.2);
}

.btn-block {
  display: block;
  width: 100%;
  text-align: center;
}

/* ===== HEADER ===== */
header {
  background: linear-gradient(135deg, var(--bg-header) 0%, #1a2339 100%);
  padding: 7rem 0 5rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 20% 150%, rgba(0, 200, 150, 0.1) 0%, transparent 70%);
}

.profile-container {
  position: relative;
  z-index: 2;
}

.profile-img {
  width: 160px;
  height: 160px;
  border-radius: 50%;
  border: 4px solid var(--primary-color);
  margin-bottom: 2rem;
  object-fit: cover;
  box-shadow: 0 0 30px rgba(0, 200, 150, 0.3);
}

header h1 {
  font-size: 3.5rem;
  margin: 0;
  letter-spacing: 1px;
  font-weight: 700;
}

header p {
  font-size: 1.3rem;
  color: var(--primary-color);
  margin-top: 0.5rem;
  font-weight: 500;
}

.social-links {
  margin-top: 2rem;
  display: flex;
  justify-content: center;
  gap: 1.5rem;
}

.social-links a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-light);
  transition: var(--transition);
}

.social-links a:hover {
  background: var(--primary-color);
  transform: translateY(-3px);
  color: #fff;
  box-shadow: 0 5px 15px rgba(0, 200, 150, 0.3);
}

#headerVideo {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 1;
  opacity: 0.25; /* adjust this for visibility */
}

header .container,
header .profile-container {
  position: relative;
  z-index: 2;
}

/* ===== NAVIGATION ===== */
nav {
  background: var(--bg-nav);
  padding: 1.2rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-weight: bold;
  font-size: 1.8rem;
  color: var(--primary-color);
  letter-spacing: 1px;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 2.5rem;
}

.nav-links a {
  color: var(--text-light);
  position: relative;
  padding: 0.5rem 0;
  font-weight: 500;
  letter-spacing: 0.5px;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary-color);
  transition: width 0.3s ease;
}

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

.theme-toggle, .mobile-menu-btn {
  background: none;
  border: none;
  color: var(--text-light);
  font-size: 1.3rem;
  cursor: pointer;
  transition: var(--transition);
  padding: 0.5rem;
}

.theme-toggle:hover, .mobile-menu-btn:hover {
  color: var(--primary-color);
}

.mobile-menu-btn {
  display: none;
}

/* ===== SECTION HEADERS ===== */
.section-header {
  text-align: center;
  margin-bottom: 5rem;
}

.section-header h2 {
  font-size: 2.8rem;
  position: relative;
  display: inline-block;
  margin-bottom: 1.5rem;
  font-weight: 700;
}

.section-header h2::after {
  content: '';
  position: absolute;
  width: 70px;
  height: 4px;
  background: var(--primary-color);
  bottom: -12px;
  left: 50%;
  transform: translateX(-50%);
  border-radius: 2px;
}

.section-header p {
  color: var(--text-muted);
  max-width: 700px;
  margin: 0 auto;
  font-size: 1.1rem;
  line-height: 1.6;
}

/* ===== ABOUT SECTION ===== */
.about-content {
  display: flex;
  gap: 4rem;
  align-items: center;
}

.about-text {
  max-width: 800px;
  margin: 0 auto;
}

.about-text p {
  margin-bottom: 1.5rem;
  font-size: 1.05rem;
}

/* ===== PROJECTS SECTION ===== */
.projects-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem;
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(400px, 1fr));
  gap: 3.5rem;
  justify-content: center;
  margin: 0 auto;
}

.project-card {
  background: var(--bg-card);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform 0.4s ease, box-shadow 0.4s ease;
  max-width: 420px;
  width: 100%;
  margin: 0 auto;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.project-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.project-img {
  height: 240px;
  overflow: hidden;
  position: relative;
}

.project-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.6s ease;
}

.project-card:hover .project-img img {
  transform: scale(1.08);
}

.project-content {
  padding: 2.5rem;
}

.project-content h3 {
  color: var(--primary-color);
  margin-bottom: 1rem;
  font-size: 1.6rem;
  font-weight: 700;
}

.project-content p {
  margin-bottom: 1.8rem;
  color: var(--text-light);
  line-height: 1.7;
  font-size: 1.05rem;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
  margin-bottom: 2rem;
}

.project-tags span {
  background: var(--primary-light);
  color: var(--primary-color);
  padding: 0.4rem 1.2rem;
  border-radius: 30px;
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.5px;
}

.project-links {
  display: flex;
  gap: 2rem;
  justify-content: flex-start;
  margin-top: 1.5rem;
}

.project-links a {
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.05rem;
}

.project-links a i {
  transition: transform 0.3s ease;
}

.project-links a:hover i {
  transform: translateX(3px);
}

/* ===== EDUCATION SECTION ===== */
.timeline {
  position: relative;
  max-width: 800px;
  margin: 0 auto;
}

.timeline::before {
  content: '';
  position: absolute;
  top: 0;
  left: 20px;
  width: 3px;
  height: 100%;
  background: var(--primary-color);
}

.timeline-item {
  background: var(--bg-card);
  border-radius: 12px;
  padding: 2rem;
  margin-bottom: 2.5rem;
  margin-left: 50px;
  position: relative;
  box-shadow: var(--shadow);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.timeline-item:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.25);
}

.timeline-item::before {
  content: '';
  position: absolute;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--primary-color);
  left: -34px;
  top: 28px;
  box-shadow: 0 0 0 4px rgba(0, 200, 150, 0.2);
}

.timeline-item h3 {
  color: var(--primary-color);
  margin-bottom: 0.8rem;
  font-size: 1.4rem;
  font-weight: 700;
}

.timeline-date {
  color: var(--text-muted);
  font-style: italic;
  margin-bottom: 1rem;
  font-size: 1rem;
}

/* ===== SKILLS SECTION ===== */
.skills {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 2.5rem;
}

.skill-card {
  background: var(--bg-card);
  border-radius: 12px;
  padding: 2rem;
  text-align: center;
  box-shadow: var(--shadow);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.skill-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.25);
}

.skill-card img {
  width: 70px;
  height: 70px;
  margin-bottom: 1.5rem;
}

.skill-card h3 {
  margin-bottom: 1.2rem;
  color: var(--primary-color);
  font-size: 1.4rem;
  font-weight: 700;
}

.skill-level {
  height: 8px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 4px;
  overflow: hidden;
  margin-top: 1rem;
}

.skill-bar {
  height: 8px;
  background-color: #4caf50; /* green */
  border-radius: 5px;
}

/* ===== PUBLICATIONS SECTION ===== */
.publications-list {
  display: grid;
  gap: 2.5rem;
}

.publication-card {
  background: var(--bg-card);
  border-radius: 12px;
  padding: 2rem;
  box-shadow: var(--shadow);
  transition: var(--transition);
  border-left: 5px solid var(--primary-color);
}

.publication-card:hover {
  transform: translateX(8px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.25);
}

.publication-card h3 {
  color: var(--primary-color);
  margin-bottom: 0.8rem;
  font-size: 1.4rem;
  font-weight: 700;
}

.publication-date, .publication-authors {
  color: var(--text-muted);
  margin-bottom: 0.8rem;
  font-size: 0.95rem;
}

.publication-abstract {
  margin-bottom: 1.5rem;
  font-size: 1.05rem;
}

.publication-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 1.05rem;
}

.publication-link i {
  font-size: 0.9rem;
}

/* ===== CONTACT SECTION ===== */
.contact-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 1.5rem;
  margin-bottom: 2.5rem;
}

.contact-item i {
  font-size: 1.8rem;
  color: var(--primary-color);
}

.contact-item h3 {
  margin-bottom: 0.8rem;
  font-size: 1.3rem;
}

.form-group {
  margin-bottom: 2rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.8rem;
  font-weight: 500;
}

.form-group input, .form-group textarea {
  width: 100%;
  padding: 1rem;
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-light);
  transition: var(--transition);
  font-family: inherit;
  font-size: 1rem;
}

.form-group input:focus, .form-group textarea:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(0, 200, 150, 0.2);
}

/* ===== FOOTER ===== */
footer {
  background: var(--bg-header);
  padding: 4rem 0 1.5rem;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer-logo h3 {
  color: var(--primary-color);
  margin-bottom: 1rem;
  font-size: 1.8rem;
  font-weight: 700;
}

.footer-links h3, .footer-social h3 {
  margin-bottom: 1.2rem;
  font-size: 1.3rem;
  font-weight: 600;
}

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

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

.footer-social .social-links {
  justify-content: flex-start;
}

.footer-bottom {
  text-align: center;
  padding-top: 2.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 0.8rem;
}

/* ===== MEDIA QUERIES ===== */
@media screen and (max-width: 1024px) {
  .projects-grid {
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 3rem;
  }
}

@media screen and (max-width: 992px) {
  .contact-content {
    grid-template-columns: 1fr;
  }
  
  .about-content {
    flex-direction: column;
    text-align: center;
  }
}

@media screen and (max-width: 768px) {
  .nav-links {
    position: fixed;
    top: 70px;
    left: -100%;
    width: 100%;
    height: calc(100vh - 70px);
    background: var(--bg-nav);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: 0.3s ease-in-out;
    padding: 2rem 0;
  }
  
  .nav-links.active {
    left: 0;
  }
  
  .nav-links li {
    margin: 1.5rem 0;
  }
  
  .mobile-menu-btn {
    display: block;
  }
  
  .timeline-item {
    width: 100%;
    margin-left: 50px;
  }
  
  .timeline::before {
    left: 20px;
  }
  
  .skills {
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  }
  
  .projects-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  
  .project-card {
    max-width: 100%;
  }
}

@media screen and (max-width: 576px) {
  section {
    padding: 5rem 0;
  }
  
  header {
    padding: 5rem 0 4rem;
  }
  
  header h1 {
    font-size: 2.8rem;
  }
  
  .section-header h2 {
    font-size: 2.3rem;
  }
  
  .projects-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }
  
  .project-card {
    max-width: 100%;
  }
  
  .project-content {
    padding: 2rem;
  }
  
  .footer-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .footer-social .social-links {
    justify-content: center;
  }
}
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

.scroll-fade, .scroll-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.in-view.scroll-fade {
  animation: fadeIn 0.8s ease forwards;
}

.in-view.scroll-up {
  animation: fadeInUp 0.8s ease forwards;
}