/**
 * T. Anil Raju — Premium Academic Portfolio
 * Dark Academia Theme with Gold & Teal Accents
 */

/* ============================================
   CSS Custom Properties (Design Tokens)
   ============================================ */
:root {
  --bg-primary: #0a192f;
  --bg-secondary: #112240;
  --bg-tertiary: #1a2f4e;
  --bg-card: rgba(17, 34, 64, 0.85);
  --text-primary: #ccd6f6;
  --text-secondary: #8892b0;
  --text-bright: #e6f1ff;
  --accent-gold: #ffd700;
  --accent-teal: #64ffda;
  --accent-blue: #57cbff;
  --gradient-gold: linear-gradient(135deg, #ffd700, #f0c040);
  --gradient-teal: linear-gradient(135deg, #64ffda, #3bc9af);
  --glass-bg: rgba(17, 34, 64, 0.6);
  --glass-border: rgba(100, 255, 218, 0.1);
  --shadow-glow: 0 0 30px rgba(100, 255, 218, 0.08);
  --shadow-card: 0 10px 40px rgba(0, 0, 0, 0.3);
  --shadow-hover: 0 20px 60px rgba(100, 255, 218, 0.12);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --transition-fast: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: all 0.5s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --font-heading: 'Playfair Display', Georgia, serif;
  --font-body: 'Inter', -apple-system, sans-serif;
}

/* ============================================
   General / Reset
   ============================================ */
*, *::before, *::after {
  box-sizing: border-box;
}

body {
  font-family: var(--font-body);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent-teal);
  text-decoration: none;
  transition: var(--transition-fast);
}
a:hover {
  color: var(--accent-gold);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--text-bright);
}

::selection {
  background: var(--accent-teal);
  color: var(--bg-primary);
}

::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--bg-tertiary);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--accent-teal);
}

/* ============================================
   Header (Sidebar)
   ============================================ */
#header {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: 300px;
  z-index: 9997;
  padding: 0;
  background: linear-gradient(180deg, #0a192f 0%, #0d1f3c 50%, #112240 100%);
  overflow-y: auto;
  border-right: 1px solid var(--glass-border);
  transition: var(--transition-smooth);
}

#header .d-flex.flex-column {
  height: 100%;
  display: flex;
  flex-direction: column;
}

#header .profile {
  text-align: center;
  padding: 25px 15px 0 15px;
  flex-shrink: 0;
}

#header .profile img {
  margin: 15px auto;
  display: block;
  width: 120px;
  height: 120px;
  object-fit: cover;
  border-radius: 50%;
  border: 3px solid rgba(100, 255, 218, 0.35);
  box-shadow: 0 0 10px rgba(100, 255, 218, 0.08), 0 0 20px rgba(100, 255, 218, 0.04);
  transition: var(--transition-smooth);
}
#header .profile img:hover {
  border-color: rgba(255, 215, 0, 0.5);
  box-shadow: 0 0 12px rgba(255, 215, 0, 0.12), 0 0 25px rgba(255, 215, 0, 0.06);
  transform: scale(1.05);
}

#header .profile h1 {
  font-size: 22px;
  margin: 0;
  padding: 0;
  font-weight: 600;
  text-align: center;
  font-family: var(--font-heading);
}
#header .profile h1 a,
#header .profile h1 a:hover {
  color: var(--text-bright);
  text-decoration: none;
}

.sidebar-tagline {
  font-size: 12px;
  color: var(--accent-teal);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-top: 6px;
  font-weight: 500;
}

#header .profile .social-links a {
  font-size: 16px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  width: 34px;
  height: 34px;
  margin: 0 3px;
  border-radius: 50%;
  border: 1px solid var(--glass-border);
  transition: var(--transition-fast);
}
#header .profile .social-links a:hover {
  background: var(--accent-teal);
  color: var(--bg-primary);
  border-color: var(--accent-teal);
  transform: translateY(-3px);
  box-shadow: 0 4px 15px rgba(100, 255, 218, 0.3);
}

/* ============================================
   Navigation Menu
   ============================================ */
.nav-menu {
  padding: 20px 0 0 0;
  width: 100%;
  margin-left: 0;
  margin-right: 0;
  flex: 1;
  display: flex;
  flex-direction: column;
}
.nav-menu ul {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  gap: 2px;
}
.nav-menu * {
  margin: 0;
  padding: 0;
  list-style: none;
}
.nav-menu .nav-link {
  display: flex;
  align-items: center;
  color: var(--text-secondary);
  padding: 12px 20px;
  margin-bottom: 0;
  font-size: 14px;
  font-weight: 500;
  border-radius: 0;
  transition: var(--transition-fast);
  position: relative;
  overflow: hidden;
}
.nav-menu .nav-link::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  width: 3px;
  height: 100%;
  background: var(--accent-teal);
  transform: scaleY(0);
  transition: transform 0.3s ease;
  border-radius: 0 2px 2px 0;
}
.nav-menu .nav-link i {
  font-size: 22px;
  padding-right: 10px;
  color: var(--text-secondary);
  transition: var(--transition-fast);
}
.nav-menu .nav-link:hover,
.nav-menu .active {
  color: var(--text-bright);
  background: rgba(100, 255, 218, 0.05);
}
.nav-menu .nav-link:hover::before,
.nav-menu .active::before {
  transform: scaleY(1);
}
.nav-menu .nav-link:hover i,
.nav-menu .active i {
  color: var(--accent-teal);
}

/* ============================================
   Mobile Navigation
   ============================================ */
.mobile-nav-toggle {
  position: fixed;
  right: 15px;
  top: 15px;
  z-index: 9998;
  border: 0;
  font-size: 24px;
  background: var(--accent-teal);
  color: var(--bg-primary);
  width: 40px;
  height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  cursor: pointer;
  box-shadow: 0 0 15px rgba(100, 255, 218, 0.3);
  transition: var(--transition-fast);
}
.mobile-nav-toggle:hover {
  background: var(--accent-gold);
}

.mobile-nav-active {
  overflow: hidden;
}
.mobile-nav-active #header {
  left: 0;
}

@media (max-width: 1199px) {
  #header {
    left: -300px;
  }
  #main, #hero {
    margin-left: 0 !important;
    width: 100% !important;
  }
}

/* ============================================
   Main Content
   ============================================ */
#main {
  margin-left: 300px;
  transition: margin-left .5s;
}

section {
  padding: 80px 0;
  overflow: hidden;
}

.section-container {
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  padding: 50px 40px;
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-card);
  backdrop-filter: blur(10px);
}

/* ============================================
   Section Title
   ============================================ */
.section-title {
  padding-bottom: 30px;
  text-align: left;
}
.section-title h2 {
  font-size: 36px;
  font-weight: 700;
  margin-bottom: 20px;
  padding-bottom: 20px;
  position: relative;
  color: var(--text-bright);
  font-family: var(--font-heading);
}
.section-title h2::after {
  content: '';
  position: absolute;
  display: block;
  width: 60px;
  height: 3px;
  background: var(--gradient-teal);
  bottom: 0;
  left: 0;
  border-radius: 2px;
}
.section-title p {
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.8;
  max-width: 700px;
}

/* ============================================
   Hero Section
   ============================================ */
#hero {
  width: 100%;
  height: 100vh;
  position: relative;
  background: radial-gradient(ellipse at 20% 50%, #1a2f4e 0%, #0a192f 50%, #060e1f 100%);
}
#hero .hero-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(10,25,47,0.7) 0%, rgba(10,25,47,0.3) 50%, rgba(10,25,47,0.7) 100%);
  z-index: 1;
}

#hero .hero-container {
  text-align: center;
  padding: 0 20px;
}

.hero-badge {
  display: inline-block;
  background: rgba(100, 255, 218, 0.1);
  border: 1px solid var(--accent-teal);
  color: var(--accent-teal);
  padding: 6px 20px;
  border-radius: 30px;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: 20px;
  animation: fadeInDown 1s ease-out;
}

#hero h1 {
  margin: 0 0 15px 0;
  font-size: 68px;
  font-weight: 800;
  line-height: 1.1;
  color: var(--text-bright);
  font-family: var(--font-heading);
  animation: fadeInUp 1s ease-out 0.3s both;
}

#hero p {
  color: var(--text-secondary);
  margin-bottom: 40px;
  font-size: 22px;
  font-weight: 300;
  animation: fadeInUp 1s ease-out 0.6s both;
}
#hero p span {
  color: var(--accent-teal);
  font-weight: 500;
  border-bottom: 2px solid var(--accent-gold);
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 40px;
  flex-wrap: wrap;
  animation: fadeInUp 1s ease-out 0.9s both;
}
.stat-item {
  text-align: center;
  padding: 20px 25px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  backdrop-filter: blur(10px);
  min-width: 130px;
  transition: var(--transition-fast);
}
.stat-item:hover {
  border-color: var(--accent-teal);
  transform: translateY(-5px);
  box-shadow: var(--shadow-glow);
}
.stat-number {
  font-size: 36px;
  font-weight: 700;
  color: var(--accent-gold);
  font-family: var(--font-heading);
  display: inline;
}
.stat-suffix {
  font-size: 24px;
  font-weight: 700;
  color: var(--accent-gold);
  font-family: var(--font-heading);
}
.stat-label {
  display: block;
  font-size: 12px;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-top: 5px;
  font-weight: 500;
}

@media (min-width: 1200px) {
  #hero {
    margin-left: 300px;
    width: calc(100% - 300px);
  }
}

@media (max-width: 768px) {
  #hero h1 {
    font-size: 40px;
  }
  #hero p {
    font-size: 18px;
  }
  .hero-stats {
    gap: 15px;
  }
  .stat-item {
    padding: 15px 18px;
    min-width: 100px;
  }
  .stat-number {
    font-size: 28px;
  }
}

/* ============================================
   About Section
   ============================================ */
.about-img-wrapper {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  max-width: 320px;
}
.about-img-wrapper img {
  width: 100%;
  display: block;
  transition: transform 0.6s ease;
}
.about-img-wrapper:hover img {
  transform: scale(1.05);
}
.about-img-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 15px;
  background: linear-gradient(transparent, rgba(10, 25, 47, 0.9));
}
.iisc-badge {
  display: inline-block;
  background: var(--gradient-gold);
  color: var(--bg-primary);
  padding: 5px 14px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.5px;
}
.iisc-badge i {
  margin-right: 5px;
}

.about .content h3 {
  font-weight: 700;
  font-size: 24px;
  color: var(--accent-teal);
  font-family: var(--font-heading);
}

.about-subtitle {
  color: var(--text-secondary);
  font-size: 14px;
  font-style: italic;
  margin-bottom: 15px;
}

.about .content ul {
  list-style: none;
  padding: 0;
}
.about .content ul li {
  margin-bottom: 12px;
  display: flex;
  align-items: flex-start;
  font-size: 14px;
  color: var(--text-primary);
}
.about .content ul i {
  font-size: 14px;
  margin-right: 8px;
  margin-top: 4px;
  color: var(--accent-teal);
  flex-shrink: 0;
}
.about .content ul strong {
  color: var(--text-bright);
  min-width: 105px;
  display: inline-block;
}

.about-research-areas h5 {
  font-size: 16px;
  color: var(--accent-gold);
  margin-bottom: 12px;
  font-family: var(--font-heading);
}
.research-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.research-tag {
  background: rgba(100, 255, 218, 0.08);
  color: var(--accent-teal);
  padding: 5px 14px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 500;
  border: 1px solid rgba(100, 255, 218, 0.15);
  transition: var(--transition-fast);
}
.research-tag:hover {
  background: rgba(100, 255, 218, 0.15);
  border-color: var(--accent-teal);
  transform: translateY(-2px);
}

/* ============================================
   Skills Section
   ============================================ */
.skills-category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  margin-bottom: 10px;
}
.skill-category-card {
  background: var(--bg-tertiary);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 15px 10px;
  text-align: center;
  transition: var(--transition-smooth);
  cursor: pointer;
}
.skill-category-card:hover, .skill-category-card.active {
  transform: translateY(-5px);
  border-color: var(--accent-teal);
  box-shadow: var(--shadow-hover);
  background: rgba(100, 255, 218, 0.05);
}
.skill-cat-icon {
  width: 40px;
  height: 40px;
  margin: 0 auto 8px;
  background: rgba(100, 255, 218, 0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  color: var(--accent-teal);
  transition: var(--transition-fast);
}
.skill-category-card:hover .skill-cat-icon, .skill-category-card.active .skill-cat-icon {
  background: var(--accent-teal);
  color: var(--bg-primary);
}
.skill-category-card h5 {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-bright);
  margin-bottom: 6px;
  font-family: var(--font-body);
}
.skill-category-card p {
  font-size: 13px;
  color: var(--text-secondary);
  margin: 0;
}

/* Skills Tags Grid */
.skills-tags-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}
.skill-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-tertiary);
  color: var(--text-bright);
  padding: 10px 20px;
  border-radius: 30px;
  font-size: 14px;
  font-weight: 500;
  border: 1px solid var(--glass-border);
  transition: var(--transition-fast);
  cursor: default;
}
.skill-chip i {
  color: var(--accent-teal);
  font-size: 15px;
}
.skill-chip:hover {
  background: rgba(100, 255, 218, 0.1);
  border-color: var(--accent-teal);
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(100, 255, 218, 0.15);
  color: var(--accent-teal);
}

@keyframes shimmer {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

/* ============================================
   Resume Section
   ============================================ */
.resume .resume-title {
  font-size: 24px;
  font-weight: 700;
  margin-top: 10px;
  margin-bottom: 20px;
  color: var(--accent-gold);
  font-family: var(--font-heading);
  padding-bottom: 10px;
  border-bottom: 1px solid var(--glass-border);
}

.resume .resume-item {
  padding: 20px 25px;
  margin-bottom: 20px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--accent-teal);
  position: relative;
  transition: var(--transition-fast);
}
.resume .resume-item:hover {
  border-left-color: var(--accent-gold);
  transform: translateX(5px);
  box-shadow: var(--shadow-glow);
}

.resume .resume-item h4 {
  font-size: 17px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-bright);
  margin-bottom: 8px;
  font-family: var(--font-body);
  letter-spacing: 0.5px;
}
.resume .resume-item h5 {
  display: inline-block;
  background: rgba(100, 255, 218, 0.1);
  color: var(--accent-teal);
  padding: 4px 14px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 10px;
  font-family: var(--font-body);
}
.resume-org {
  color: var(--accent-gold);
  font-size: 14px;
  margin-bottom: 10px;
}
.resume .resume-item ul {
  padding-left: 18px;
  margin: 0;
}
.resume .resume-item ul li {
  padding-bottom: 8px;
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ============================================
   Publications Section
   ============================================ */
.publications-tabs {
  display: flex;
  gap: 15px;
  margin-bottom: 30px;
}
.pub-tab {
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--glass-border);
  padding: 10px 25px;
  border-radius: 30px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-fast);
  font-family: var(--font-body);
}
.pub-tab:hover,
.pub-tab.active {
  background: var(--accent-teal);
  color: var(--bg-primary);
  border-color: var(--accent-teal);
}

.pub-item {
  display: flex;
  gap: 20px;
  padding: 20px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  margin-bottom: 15px;
  border: 1px solid var(--glass-border);
  transition: var(--transition-fast);
  align-items: flex-start;
}
.pub-item:hover {
  border-color: rgba(100, 255, 218, 0.3);
  transform: translateX(5px);
}
.pub-number {
  background: rgba(255, 215, 0, 0.1);
  color: var(--accent-gold);
  min-width: 45px;
  height: 45px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  font-size: 13px;
  font-weight: 700;
  border: 1px solid rgba(255, 215, 0, 0.2);
  flex-shrink: 0;
}
.pub-content h5 {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-bright);
  margin-bottom: 6px;
  font-family: var(--font-body);
  line-height: 1.5;
}
.pub-authors {
  font-size: 13px;
  color: var(--accent-teal);
  margin-bottom: 4px;
  font-style: italic;
}
.pub-venue {
  font-size: 12px;
  color: var(--text-secondary);
  margin: 0;
}

/* ============================================
   Research Section
   ============================================ */
.research-card {
  background: var(--bg-tertiary);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--glass-border);
  transition: var(--transition-smooth);
  height: 100%;
}
.research-card:hover {
  transform: translateY(-10px);
  border-color: var(--accent-teal);
  box-shadow: var(--shadow-hover);
}
.research-card-img {
  overflow: hidden;
  height: 200px;
}
.research-card-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.6s ease;
}
.research-card:hover .research-card-img img {
  transform: scale(1.1);
}
.research-card-body {
  padding: 20px;
}
.research-card-body h5 {
  font-size: 17px;
  font-weight: 600;
  color: var(--text-bright);
  margin-bottom: 10px;
  font-family: var(--font-body);
}
.research-card-body h5 i {
  color: var(--accent-teal);
  margin-right: 8px;
}
.research-card-body p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin: 0;
}

/* ============================================
   Certifications Section
   ============================================ */
.certifications-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 15px;
}
.cert-card {
  display: flex;
  align-items: center;
  gap: 15px;
  padding: 18px 20px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  border: 1px solid var(--glass-border);
  transition: var(--transition-fast);
}
.cert-card:hover {
  border-color: var(--accent-gold);
  transform: translateX(5px);
  box-shadow: 0 0 20px rgba(255, 215, 0, 0.08);
}
.cert-icon {
  width: 42px;
  height: 42px;
  background: rgba(255, 215, 0, 0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.cert-icon i {
  color: var(--accent-gold);
  font-size: 18px;
}
.cert-content h5 {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-bright);
  margin-bottom: 3px;
  font-family: var(--font-body);
}
.cert-content p {
  font-size: 12px;
  color: var(--text-secondary);
  margin: 0;
}

/* ============================================
   Contact Section
   ============================================ */
.info-box {
  background: var(--bg-tertiary);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 30px;
}
.info-item {
  display: flex;
  align-items: flex-start;
  gap: 15px;
  margin-bottom: 25px;
}
.info-item:last-child {
  margin-bottom: 0;
}
.info-icon {
  width: 45px;
  height: 45px;
  background: rgba(100, 255, 218, 0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.info-icon i {
  font-size: 20px;
  color: var(--accent-teal);
}
.info-item h4 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-bright);
  margin-bottom: 3px;
  font-family: var(--font-body);
}
.info-item p {
  font-size: 14px;
  color: var(--text-secondary);
  margin: 0;
}
.info-item a {
  color: var(--text-secondary);
}
.info-item a:hover {
  color: var(--accent-teal);
}

.contact-form {
  background: var(--bg-tertiary);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 30px;
}
.contact-form .form-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 1px;
}
.contact-form .form-control {
  background: var(--bg-secondary);
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
  border-radius: var(--radius-sm);
  padding: 10px 15px;
  font-size: 14px;
  transition: var(--transition-fast);
}
.contact-form .form-control:focus {
  border-color: var(--accent-teal);
  box-shadow: 0 0 10px rgba(100, 255, 218, 0.1);
  background: var(--bg-primary);
  color: var(--text-bright);
}
.contact-form .form-control::placeholder {
  color: var(--text-secondary);
  opacity: 0.5;
}

.btn-submit {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--accent-teal);
  color: var(--bg-primary);
  border: 2px solid var(--accent-teal);
  padding: 12px 30px;
  border-radius: 30px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-fast);
  text-transform: uppercase;
  letter-spacing: 1px;
}
.btn-submit:hover {
  background: transparent;
  color: var(--accent-teal);
  transform: translateY(-3px);
  box-shadow: 0 5px 20px rgba(100, 255, 218, 0.25);
}
.btn-submit i {
  font-size: 20px;
}

/* ============================================
   Footer
   ============================================ */
#footer {
  background: var(--bg-secondary);
  padding: 25px 0;
  border-top: 1px solid var(--glass-border);
  margin-left: 300px;
}
#footer .copyright {
  font-size: 14px;
  color: var(--text-secondary);
}
#footer .copyright strong span {
  color: var(--accent-teal);
}
#footer .credits {
  font-size: 12px;
  color: var(--text-secondary);
  opacity: 0.7;
}

@media (max-width: 1199px) {
  #footer {
    margin-left: 0;
  }
}

/* ============================================
   Back to Top Button
   ============================================ */
.back-to-top {
  position: fixed;
  visibility: hidden;
  opacity: 0;
  right: 20px;
  bottom: 20px;
  z-index: 996;
  background: var(--accent-teal);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  transition: var(--transition-fast);
  color: var(--bg-primary);
  font-size: 22px;
  box-shadow: 0 0 15px rgba(100, 255, 218, 0.3);
}
.back-to-top:hover {
  background: var(--accent-gold);
  color: var(--bg-primary);
  transform: translateY(-5px);
}
.back-to-top.active {
  visibility: visible;
  opacity: 1;
}

/* ============================================
   Animations
   ============================================ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

@keyframes float {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(-15px); }
}

@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 5px rgba(100, 255, 218, 0.2); }
  50% { box-shadow: 0 0 20px rgba(100, 255, 218, 0.4); }
}

/* ============================================
   Cross-Platform Compatibility & Fixes
   ============================================ */

/* iOS Safari: Fix 100vh issue */
@supports (-webkit-touch-callout: none) {
  #hero {
    height: -webkit-fill-available;
  }
}

/* Touch-friendly minimum tap targets (44x44 for iOS, 48x48 for Android) */
@media (pointer: coarse) {
  .nav-menu .nav-link {
    padding: 14px 15px;
    min-height: 48px;
  }
  .social-links a {
    min-width: 44px;
    min-height: 44px;
  }
  .pub-tab {
    padding: 14px 25px;
    min-height: 48px;
  }
  .btn-submit {
    padding: 16px 30px;
    min-height: 48px;
  }
  .back-to-top {
    width: 50px;
    height: 50px;
  }
  .info-icon {
    width: 48px;
    height: 48px;
  }
}

/* Smooth scrolling for all platforms */
html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
}

/* Fix image rendering across all platforms */
img {
  max-width: 100%;
  height: auto;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  image-rendering: -webkit-optimize-contrast;
}

/* Prevent text selection highlight color from looking odd on mobile */
::selection {
  background: var(--accent-teal);
  color: var(--bg-primary);
}
::-moz-selection {
  background: var(--accent-teal);
  color: var(--bg-primary);
}

/* ============================================
   Responsive: Large Desktops (> 1400px)
   ============================================ */
@media (min-width: 1400px) {
  .section-container {
    max-width: 1100px;
    margin: 0 auto;
  }
  #hero h1 {
    font-size: 76px;
  }
}

/* ============================================
   Responsive: Laptops / Small Desktops (1200-1399px)
   ============================================ */
@media (max-width: 1399px) and (min-width: 1200px) {
  .section-container {
    padding: 45px 35px;
  }
}

/* ============================================
   Responsive: Tablets Landscape / Small Laptops (992-1199px)
   ============================================ */
@media (max-width: 1199px) {
  #header {
    left: -300px;
  }
  #main, #hero, #footer {
    margin-left: 0 !important;
    width: 100% !important;
  }
  .section-container {
    padding: 40px 25px;
    margin: 0 15px;
  }
}

/* ============================================
   Responsive: Tablets Portrait (768-991px)
   ============================================ */
@media (max-width: 992px) {
  section {
    padding: 60px 0;
  }
  .section-container {
    padding: 35px 20px;
    margin: 0 12px;
  }
  .section-title h2 {
    font-size: 28px;
  }
  .section-title p {
    font-size: 14px;
  }
  .certifications-grid {
    grid-template-columns: 1fr;
  }
  .skills-category-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
  }
  #hero h1 {
    font-size: 50px;
  }
  #hero p {
    font-size: 20px;
  }
  .hero-stats {
    gap: 20px;
  }
  .stat-item {
    padding: 18px 22px;
    min-width: 120px;
  }
  .about-img-wrapper {
    max-width: 280px;
    margin-bottom: 25px;
  }
  .about .content ul strong {
    min-width: 90px;
  }
  .resume .resume-item {
    padding: 18px 20px;
  }
  .pub-item {
    padding: 16px;
  }
  .research-card-img {
    height: 180px;
  }
  .info-box {
    padding: 25px;
    margin-bottom: 20px;
  }
  .contact-form {
    padding: 25px;
  }
}

/* ============================================
   Responsive: Large Phones / Phablets (576-767px)
   ============================================ */
@media (max-width: 767px) {
  section {
    padding: 50px 0;
  }
  .section-container {
    padding: 30px 18px;
    margin: 0 10px;
    border-radius: var(--radius-md);
  }
  .section-title h2 {
    font-size: 26px;
  }
  #hero h1 {
    font-size: 42px;
    line-height: 1.15;
  }
  #hero p {
    font-size: 18px;
    margin-bottom: 30px;
  }
  .hero-badge {
    font-size: 11px;
    padding: 5px 16px;
  }
  .hero-stats {
    gap: 12px;
    flex-wrap: wrap;
    justify-content: center;
  }
  .stat-item {
    padding: 15px 18px;
    min-width: 110px;
    flex: 1 1 calc(50% - 12px);
    max-width: calc(50% - 6px);
  }
  .stat-number {
    font-size: 30px;
  }
  .stat-label {
    font-size: 10px;
    letter-spacing: 1px;
  }

  /* About section: stack on mobile */
  .about .row .col-lg-4 {
    margin-bottom: 25px;
  }
  .about-img-wrapper {
    max-width: 250px;
    margin: 0 auto 20px;
  }
  .about .content h3 {
    font-size: 20px;
    text-align: center;
  }
  .about-subtitle {
    text-align: center;
  }
  .research-tags {
    justify-content: center;
  }
  .about .content ul li {
    font-size: 13px;
  }

  /* Skills */
  .skills-category-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }
  .skill-category-card {
    padding: 20px 15px;
  }
  .skill-category-card h5 {
    font-size: 14px;
  }
  .skill-category-card p {
    font-size: 12px;
  }

  /* Resume items */
  .resume .resume-title {
    font-size: 20px;
  }
  .resume .resume-item h4 {
    font-size: 15px;
  }
  .resume .resume-item ul li {
    font-size: 12px;
  }

  /* Publications */
  .pub-item {
    flex-direction: row;
    gap: 15px;
    padding: 15px;
  }
  .pub-number {
    min-width: 40px;
    height: 40px;
    font-size: 12px;
  }
  .pub-content h5 {
    font-size: 14px;
  }
  .pub-authors {
    font-size: 12px;
  }
  .pub-venue {
    font-size: 11px;
  }
  .publications-tabs {
    flex-direction: row;
    justify-content: center;
  }
  .pub-tab {
    flex: 1;
    text-align: center;
  }

  /* Research cards */
  .research-card-body {
    padding: 16px;
  }
  .research-card-body h5 {
    font-size: 15px;
  }
  .research-card-body p {
    font-size: 12px;
  }

  /* Certifications */
  .certifications-grid {
    grid-template-columns: 1fr;
    gap: 10px;
  }
  .cert-card {
    padding: 15px;
  }

  /* Contact */
  .info-box {
    padding: 20px;
  }
  .contact-form {
    padding: 20px;
  }
  .contact-form .form-label {
    font-size: 12px;
  }

  /* Footer */
  #footer {
    padding: 20px 15px;
  }
  #footer .copyright {
    font-size: 12px;
  }
  #footer .credits {
    font-size: 11px;
  }
}

/* ============================================
   Responsive: Small Phones (480-575px)
   ============================================ */
@media (max-width: 575px) {
  section {
    padding: 40px 0;
  }
  .section-container {
    padding: 25px 15px;
    margin: 0 8px;
  }
  .section-title h2 {
    font-size: 24px;
    padding-bottom: 15px;
    margin-bottom: 15px;
  }
  .section-title p {
    font-size: 13px;
    line-height: 1.7;
  }
  #hero h1 {
    font-size: 36px;
  }
  #hero p {
    font-size: 16px;
  }
  .hero-stats {
    gap: 8px;
  }
  .stat-item {
    padding: 12px 14px;
    min-width: 95px;
  }
  .stat-number {
    font-size: 26px;
  }

  .about .content ul li {
    flex-direction: column;
    align-items: flex-start;
    margin-bottom: 10px;
  }
  .about .content ul strong {
    min-width: unset;
    margin-bottom: 2px;
  }

  .skills-category-grid {
    grid-template-columns: 1fr 1fr;
    gap: 10px;
  }
  .skill-cat-icon {
    width: 45px;
    height: 45px;
    font-size: 18px;
  }

  .pub-item {
    flex-direction: column;
    gap: 10px;
  }

  .resume .resume-item {
    padding: 15px;
  }
  .resume .resume-item h4 {
    font-size: 14px;
  }
  .resume .resume-item h5 {
    font-size: 12px;
  }

  .research-card-img {
    height: 160px;
  }

  .btn-submit {
    width: 100%;
    justify-content: center;
    padding: 14px 20px;
    font-size: 14px;
  }
}

/* ============================================
   Responsive: Tiny Phones (< 380px) — iPhone SE, older Androids
   ============================================ */
@media (max-width: 379px) {
  .section-container {
    padding: 20px 12px;
    margin: 0 5px;
  }
  #hero h1 {
    font-size: 30px;
  }
  #hero p {
    font-size: 14px;
  }
  .hero-badge {
    font-size: 10px;
    padding: 4px 12px;
  }
  .hero-stats {
    gap: 6px;
  }
  .stat-item {
    padding: 10px 10px;
    min-width: 70px;
    flex: 1 1 calc(50% - 6px);
  }
  .stat-number {
    font-size: 22px;
  }
  .stat-suffix {
    font-size: 16px;
  }
  .stat-label {
    font-size: 9px;
    letter-spacing: 0.5px;
  }
  .section-title h2 {
    font-size: 22px;
  }
  .about-img-wrapper {
    max-width: 200px;
  }
  .skills-category-grid {
    grid-template-columns: 1fr;
  }
  .skill-category-card {
    padding: 15px 12px;
  }
  .pub-tab {
    padding: 10px 15px;
    font-size: 13px;
  }
  .cert-card {
    padding: 12px;
    gap: 10px;
  }
  .cert-icon {
    width: 36px;
    height: 36px;
  }
  .cert-content h5 {
    font-size: 13px;
  }
  .cert-content p {
    font-size: 11px;
  }
  .research-card-img {
    height: 140px;
  }
  .info-item h4 {
    font-size: 14px;
  }
  .info-item p,
  .info-item a {
    font-size: 12px;
  }
}

/* ============================================
   Landscape Mode on Phones
   ============================================ */
@media (max-height: 500px) and (orientation: landscape) {
  #hero {
    height: auto;
    min-height: 100vh;
    padding: 60px 20px;
  }
  #hero h1 {
    font-size: 32px;
  }
  .hero-stats {
    gap: 10px;
  }
  .stat-item {
    padding: 10px 15px;
  }
}

/* ============================================
   Print Styles
   ============================================ */
@media print {
  #header,
  .mobile-nav-toggle,
  .back-to-top,
  #hero-particles,
  .hero-overlay {
    display: none !important;
  }
  #main, #hero, #footer {
    margin-left: 0 !important;
    width: 100% !important;
  }
  body {
    background: #fff;
    color: #000;
  }
  .section-container {
    box-shadow: none;
    border: 1px solid #ddd;
  }
}

/* ============================================
   Reduce Motion (Accessibility)
   ============================================ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .progress-bar-fill::after {
    animation: none;
  }
}