/*=============== GOOGLE FONTS ===============*/
@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@300;400;500;600;700&family=Inter:wght@300;400;500;600;700&display=swap');

/*=============== VARIABLES CSS ===============*/
:root {
  --header-height: 5rem;
  
  /*========== Colors ==========*/
  --primary-color: #2563eb;
  --primary-dark: #1e40af;
  --secondary-color: #8b5cf6;
  --accent-color: #06b6d4;
  
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  
  /*========== Font and typography ==========*/
  --font-heading: 'Space Grotesk', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  
  --fs-xl: clamp(2.5rem, 5vw, 4rem);
  --fs-lg: clamp(2rem, 4vw, 3rem);
  --fs-md: clamp(1.5rem, 3vw, 2rem);
  --fs-base: 1rem;
  --fs-sm: 0.875rem;
  --fs-xs: 0.75rem;
  
  /*========== Spacing ==========*/
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;
  --spacing-3xl: 6rem;
  
  /*========== Border radius ==========*/
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;
  
  /*========== Transitions ==========*/
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
  
  /*========== Z-index ==========*/
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal: 1040;
  --z-tooltip: 1050;
}

/*=============== DARK THEME ===============*/
body.dark-theme {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #64748b;
  
  --border-color: #334155;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5);
}

body.dark-theme .bg-animation {
  background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
}

body.dark-theme .bg-animation::before {
  background: linear-gradient(135deg, #1e40af, #7c3aed);
  opacity: 0.15;
}

body.dark-theme .bg-animation::after {
  background: linear-gradient(135deg, #0891b2, #7c3aed);
  opacity: 0.15;
}

body.dark-theme .header {
  background: rgba(15, 23, 42, 0.8);
  border-bottom: 1px solid var(--border-color);
}

body.dark-theme .skill-category,
body.dark-theme .project-card,
body.dark-theme .project-card-large,
body.dark-theme .publication-card,
body.dark-theme .timeline-content,
body.dark-theme .contact-card,
body.dark-theme .contact-form-container,
body.dark-theme .highlight-item,
body.dark-theme .skill-group {
  background: var(--bg-secondary);
  border-color: var(--border-color);
}

body.dark-theme .floating-card,
body.dark-theme .skills-wheel {
  background: var(--bg-secondary);
  border-color: var(--border-color);
}

body.dark-theme .nav__list {
  background: rgba(15, 23, 42, 0.98);
}

body.dark-theme .skill-tag,
body.dark-theme .tech-tag,
body.dark-theme .project-tech span {
  background: var(--bg-tertiary);
  border-color: var(--border-color);
  color: var(--text-secondary);
}

body.dark-theme .category-tag {
  background: var(--bg-tertiary);
  color: var(--text-muted);
}

body.dark-theme .form-group input,
body.dark-theme .form-group textarea {
  background: var(--bg-tertiary);
  border-color: var(--border-color);
  color: var(--text-primary);
}

body.dark-theme .form-group input:focus,
body.dark-theme .form-group textarea:focus {
  background: var(--bg-primary);
  border-color: var(--primary-color);
}

body.dark-theme .filter-btn {
  background: var(--bg-secondary);
  border-color: var(--border-color);
  color: var(--text-secondary);
}

body.dark-theme .stat-card {
  background: var(--bg-secondary);
}

body.dark-theme .btn-secondary {
  background: var(--bg-secondary);
  border-color: var(--border-color);
  color: var(--text-primary);
}

body.dark-theme .social-link {
  background: var(--bg-secondary);
  border-color: var(--border-color);
}

body.dark-theme .timeline::before {
  background: var(--border-color);
}

body.dark-theme .timeline-icon {
  box-shadow: 0 0 0 4px var(--bg-primary), 0 0 0 6px var(--border-color);
}

body.dark-theme .hero-badge {
  background: var(--bg-secondary);
  border-color: var(--border-color);
}

body.dark-theme .skill-bar {
  background: var(--bg-tertiary);
}

body.dark-theme .timeline-date {
  background: var(--bg-tertiary);
}

body.dark-theme .projects-hero,
body.dark-theme .about-hero,
body.dark-theme .contact-hero {
  background: var(--bg-primary);
}

body.dark-theme .page-title,
body.dark-theme .section-title,
body.dark-theme h1, 
body.dark-theme h2, 
body.dark-theme h3, 
body.dark-theme h4 {
  color: var(--text-primary);
}

body.dark-theme .page-subtitle,
body.dark-theme p {
  color: var(--text-secondary);
}

body.dark-theme .projects-section {
  background: var(--bg-primary);
}

body.dark-theme .section {
  background: var(--bg-primary);
}

body.dark-theme .about-content {
  background: var(--bg-primary);
}

body.dark-theme .about-skills {
  background: var(--bg-secondary);
}

body.dark-theme .featured-projects {
  background: var(--bg-primary);
}

body.dark-theme .skills-section {
  background: var(--bg-secondary);
}

body.dark-theme .publications {
  background: var(--bg-secondary);
}

body.dark-theme .timeline-section {
  background: var(--bg-primary);
}

body.dark-theme .contact-content {
  background: var(--bg-primary);
}

body.dark-theme .footer {
  background: var(--bg-secondary);
  border-top-color: var(--border-color);
}

body.dark-theme .footer-brand p,
body.dark-theme .footer-column a {
  color: var(--text-secondary);
}

body.dark-theme .footer-bottom p {
  color: var(--text-muted);
}

body.dark-theme .project-image {
  background: var(--bg-tertiary);
}

body.dark-theme .project-content {
  background: transparent;
}

body.dark-theme .project-header,
body.dark-theme .project-title {
  color: var(--text-primary);
}

body.dark-theme .project-description {
  color: var(--text-secondary);
}

body.dark-theme .project-footer {
  border-top-color: var(--border-color);
}

body.dark-theme .project-links a {
  background: var(--bg-tertiary);
  border-color: var(--border-color);
  color: var(--text-secondary);
}

body.dark-theme .project-links a:hover {
  background: var(--primary-color);
  color: white;
}

body.dark-theme .project-link-btn {
  color: var(--primary-color);
}

body.dark-theme .overlay-btn {
  background: white;
  color: var(--primary-color);
}

body.dark-theme .project-badge {
  background: var(--primary-color);
  color: white;
}

body.dark-theme .project-overlay {
  background: rgba(37, 99, 235, 0.95);
}

body.dark-theme ::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

body.dark-theme ::-webkit-scrollbar-thumb {
  background: var(--primary-color);
}

body.dark-theme .section-header {
  color: var(--text-primary);
}

body.dark-theme .view-all {
  color: var(--primary-color);
}

body.dark-theme .project-tech-tags .tech-tag {
  background: var(--bg-tertiary);
  border-color: var(--border-color);
  color: var(--text-secondary);
}

body.dark-theme .project-tags .category-tag {
  background: var(--bg-tertiary);
  color: var(--text-muted);
}

/*=============== BASE ===============*/
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  font-size: var(--fs-base);
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.2;
  color: var(--text-primary);
}

h1 { font-size: var(--fs-xl); }
h2 { font-size: var(--fs-lg); }
h3 { font-size: var(--fs-md); }

p {
  margin-bottom: var(--spacing-md);
  color: var(--text-secondary);
}

ul { list-style: none; }
a {
  text-decoration: none;
  color: inherit;
  transition: color var(--transition-base);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

button {
  cursor: pointer;
  border: none;
  outline: none;
  font-family: var(--font-body);
  transition: all var(--transition-base);
}

/*=============== UTILITIES ===============*/
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

@media (min-width: 1536px) {
  .container {
    max-width: 1400px;
  }
}

.section {
  padding: var(--spacing-3xl) 0;
}

.section-title {
  font-size: var(--fs-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-xl);
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -0.5rem;
  width: 60%;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
  border-radius: var(--radius-full);
}

.gradient-text {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/*=============== ANIMATED BACKGROUND ===============*/
.bg-animation {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  background: linear-gradient(135deg, #f8fafc 0%, #ffffff 100%);
  overflow: hidden;
  pointer-events: none;
}

.bg-animation::before,
.bg-animation::after {
  content: '';
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
  opacity: 0.3;
  animation: float 20s ease-in-out infinite;
}

.bg-animation::before {
  width: 500px;
  height: 500px;
  background: linear-gradient(135deg, #3b82f6, #8b5cf6);
  top: -250px;
  right: -250px;
}

.bg-animation::after {
  width: 400px;
  height: 400px;
  background: linear-gradient(135deg, #06b6d4, #8b5cf6);
  bottom: -200px;
  left: -200px;
  animation-delay: -10s;
}

@keyframes float {
  0%, 100% {
    transform: translate(0, 0) scale(1);
  }
  33% {
    transform: translate(30px, -30px) scale(1.1);
  }
  66% {
    transform: translate(-20px, 20px) scale(0.9);
  }
}

/*=============== HEADER ===============*/
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--border-color);
  z-index: var(--z-fixed);
  transition: all var(--transition-base);
}

.header.bg-header {
  box-shadow: var(--shadow-md);
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: var(--header-height);
  position: relative;
}

.nav__logo {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
  transition: transform var(--transition-base);
}

.nav__logo:hover {
  transform: scale(1.05);
}

.nav__menu {
  margin-left: auto;
  margin-right: var(--spacing-lg);
}

.nav__list {
  display: flex;
  gap: var(--spacing-xl);
  align-items: center;
}

.nav__link {
  font-size: var(--fs-sm);
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: 0.5rem 0;
  transition: color var(--transition-base);
}

.nav__link::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background: var(--primary-color);
  transition: width var(--transition-base);
}

.nav__link:hover,
.nav__link.active-link {
  color: var(--primary-color);
}

.nav__link:hover::after,
.nav__link.active-link::after {
  width: 100%;
}

.nav__actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.change-theme {
  font-size: 1.25rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-base);
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
}

.change-theme:hover {
  color: var(--primary-color);
  background: var(--bg-secondary);
}

.nav__toggle,
.nav__close {
  display: none;
}

/*=============== HERO SECTION ===============*/
.hero-section {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: calc(var(--header-height) + var(--spacing-xl));
  padding-bottom: var(--spacing-3xl);
}

.hero-content {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
}

.hero-text {
  animation: fadeInUp 0.8s ease;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: 0.5rem 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  font-size: var(--fs-sm);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  font-weight: 500;
}

.badge-dot {
  width: 8px;
  height: 8px;
  background: #10b981;
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.1); }
}

.hero-title {
  font-size: var(--fs-xl);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-size: var(--fs-md);
  color: var(--text-secondary);
  font-weight: 500;
  margin-bottom: var(--spacing-lg);
}

.hero-description {
  font-size: 1.125rem;
  color: var(--text-secondary);
  line-height: 1.7;
  max-width: 600px;
  margin-bottom: var(--spacing-xl);
}

.hero-stats {
  display: none;
}

.stat-item {
  display: none;
}

.stat-number {
  display: none;
}

.stat-label {
  display: none;
}

.hero-buttons {
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
  padding: 0.875rem 1.75rem;
  border-radius: var(--radius-md);
  font-weight: 500;
  font-size: var(--fs-base);
  transition: all var(--transition-base);
  white-space: nowrap;
}

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

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

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

.btn-secondary:hover {
  background: var(--bg-tertiary);
  border-color: var(--primary-color);
}

.social-links {
  display: flex;
  gap: var(--spacing-sm);
}

.social-link {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 1.25rem;
  transition: all var(--transition-base);
}

.social-link:hover {
  background: var(--primary-color);
  border-color: var(--primary-color);
  color: white;
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.hero-visual {
  position: relative;
  height: 500px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.floating-card {
  position: absolute;
  padding: var(--spacing-md) var(--spacing-lg);
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  box-shadow: var(--shadow-lg);
  animation: float-smooth 3s ease-in-out infinite;
}

.floating-card i {
  font-size: 1.75rem;
  color: var(--primary-color);
}

.floating-card span {
  font-weight: 600;
  color: var(--text-primary);
}

.card-1 {
  top: 10%;
  left: 0;
  animation-delay: 0s;
}

.card-2 {
  top: 30%;
  right: 5%;
  animation-delay: 0.5s;
}

.card-3 {
  bottom: 35%;
  left: 10%;
  animation-delay: 1s;
}

.card-4 {
  bottom: 15%;
  right: 10%;
  animation-delay: 1.5s;
}

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

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

/*=============== SKILLS SECTION ===============*/
.skills-section {
  background: var(--bg-secondary);
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

.skill-category {
  padding: var(--spacing-xl);
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  transition: all var(--transition-base);
}

.skill-category:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary-color);
}

.category-icon {
  width: 56px;
  height: 56px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--spacing-md);
}

.category-icon i {
  font-size: 1.75rem;
  color: white;
}

.skill-category h3 {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-md);
  font-weight: 600;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.skill-tag {
  padding: 0.375rem 0.875rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  font-size: var(--fs-sm);
  color: var(--text-secondary);
  font-weight: 500;
  transition: all var(--transition-base);
}

.skill-tag:hover {
  background: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
  transform: translateY(-2px);
}

/*=============== FEATURED PROJECTS ===============*/
.featured-projects {
  background: white;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-xl);
}

.view-all {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  color: var(--primary-color);
  font-weight: 500;
  font-size: var(--fs-sm);
  transition: gap var(--transition-base);
}

.view-all:hover {
  gap: var(--spacing-sm);
}

.projects-showcase {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
  gap: var(--spacing-xl);
}

.project-card-large {
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  overflow: hidden;
  transition: all var(--transition-base);
}

.project-card-large:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary-color);
}

.project-image-container {
  position: relative;
  overflow: hidden;
  background: var(--bg-secondary);
}

.project-content {
  padding: var(--spacing-xl);
}

.project-content h3 {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-sm);
  font-weight: 600;
}

.project-content p {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
  line-height: 1.6;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-bottom: var(--spacing-md);
}

.project-tech span {
  padding: 0.375rem 0.875rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  font-size: var(--fs-sm);
  color: var(--text-secondary);
  font-weight: 500;
}

.project-link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  color: var(--primary-color);
  font-weight: 600;
  font-size: var(--fs-sm);
  transition: gap var(--transition-base);
}

.project-link:hover {
  gap: var(--spacing-sm);
}

/*=============== ABOUT PAGE ===============*/
.about-hero,
.projects-hero,
.contact-hero {
  padding: calc(var(--header-height) + var(--spacing-3xl)) 0 var(--spacing-3xl);
  text-align: center;
  background: var(--bg-secondary);
}

.page-title {
  font-size: var(--fs-xl);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.02em;
}

.page-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

.about-content {
  padding: var(--spacing-3xl) 0;
}

.about-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: var(--spacing-3xl);
  align-items: start;
}

.about-text h2 {
  font-size: var(--fs-lg);
  margin-bottom: var(--spacing-lg);
  font-weight: 600;
}

.about-text p {
  font-size: 1.0625rem;
  line-height: 1.7;
  margin-bottom: var(--spacing-md);
}

.about-highlights {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  margin-top: var(--spacing-xl);
}

.highlight-item {
  display: flex;
  gap: var(--spacing-md);
  padding: var(--spacing-lg);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
}

.highlight-item:hover {
  border-color: var(--primary-color);
  transform: translateX(5px);
  box-shadow: var(--shadow-md);
}

.highlight-item i {
  font-size: 1.75rem;
  color: var(--primary-color);
  flex-shrink: 0;
}

.highlight-item h4 {
  font-size: 1.125rem;
  margin-bottom: 0.25rem;
  font-weight: 600;
}

.highlight-item p {
  font-size: var(--fs-sm);
  margin: 0;
  color: var(--text-muted);
}

.about-visual {
  position: sticky;
  top: calc(var(--header-height) + var(--spacing-lg));
  display: flex;
  justify-content: center;
  align-items: center;
}

.skills-wheel {
  position: relative;
  width: 320px;
  height: 320px;
  background: white;
  border: 1px solid var(--border-color);
  border-radius: 50%;
  box-shadow: var(--shadow-xl);
}

.wheel-item {
  position: absolute;
  width: 64px;
  height: 64px;
  background: white;
  border: 2px solid var(--border-color);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  color: var(--primary-color);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base);
}

.wheel-item:hover {
  transform: scale(1.1);
  border-color: var(--primary-color);
  box-shadow: var(--shadow-lg);
}

.about-skills {
  padding: var(--spacing-3xl) 0;
  background: var(--bg-secondary);
}

.skills-detailed {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
  gap: var(--spacing-xl);
}

.skill-group {
  padding: var(--spacing-xl);
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
}

.skill-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.skill-header i {
  font-size: 1.75rem;
  color: var(--primary-color);
}

.skill-header h3 {
  font-size: 1.25rem;
  font-weight: 600;
}

.skill-items {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.skill-item span {
  display: block;
  margin-bottom: var(--spacing-xs);
  font-weight: 500;
  color: var(--text-primary);
  font-size: var(--fs-sm);
}

.skill-bar {
  width: 100%;
  height: 6px;
  background: var(--bg-secondary);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.skill-progress {
  height: 100%;
  background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
  border-radius: var(--radius-full);
  transition: width 1s ease;
}

.timeline-section {
  padding: var(--spacing-3xl) 0;
}

.timeline {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  padding-left: var(--spacing-3xl);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--border-color);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--spacing-xl);
}

.timeline-icon {
  position: absolute;
  left: calc(-1 * var(--spacing-3xl) - 20px);
  top: 0;
  width: 44px;
  height: 44px;
  background: var(--primary-color);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 0 4px white, 0 0 0 6px var(--border-color);
}

.timeline-icon i {
  font-size: 1.25rem;
  color: white;
}

.timeline-content {
  padding: var(--spacing-lg);
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
}

.timeline-content:hover {
  border-color: var(--primary-color);
  box-shadow: var(--shadow-md);
  transform: translateX(5px);
}

.timeline-date {
  display: inline-block;
  padding: 0.375rem 0.875rem;
  background: var(--bg-secondary);
  border-radius: var(--radius-full);
  font-size: var(--fs-xs);
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.timeline-content h3 {
  font-size: 1.25rem;
  margin-bottom: 0.25rem;
  font-weight: 600;
}

.timeline-content h4 {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
  font-size: 1rem;
}

.timeline-content p {
  color: var(--text-secondary);
  line-height: 1.6;
  margin: 0;
  font-size: var(--fs-sm);
}

.publications {
  padding: var(--spacing-3xl) 0;
  background: var(--bg-secondary);
}

.publications-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
  gap: var(--spacing-xl);
}

.publication-card {
  padding: var(--spacing-xl);
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  transition: all var(--transition-base);
}

.publication-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary-color);
}

.publication-icon {
  width: 56px;
  height: 56px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--spacing-md);
}

.publication-icon i {
  font-size: 1.75rem;
  color: white;
}

.publication-card h3 {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-sm);
  font-weight: 600;
}

.publication-card p {
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: var(--spacing-md);
  font-size: var(--fs-sm);
}

.publication-badge {
  display: inline-block;
  padding: 0.375rem 0.875rem;
  background: var(--primary-color);
  color: white;
  border-radius: var(--radius-full);
  font-size: var(--fs-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/*=============== PROJECTS PAGE ===============*/
.filter-tabs {
  display: none;
}

.filter-btn {
  display: none;
}

.project-stats {
  display: none;
}

.stats-grid {
  display: none;
}

.stat-card {
  display: none;
}

.projects-section {
  padding: var(--spacing-3xl) 0;
  background: var(--bg-secondary);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
  gap: var(--spacing-xl);
}

.project-card {
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  overflow: hidden;
  transition: all var(--transition-base);
}

.project-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary-color);
}

.project-image {
  position: relative;
  overflow: hidden;
  background: var(--bg-secondary);
  height: 250px;
}

.project-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(37, 99, 235, 0.95);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-md);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.project-card:hover .project-overlay {
  opacity: 1;
}

.overlay-btn {
  width: 48px;
  height: 48px;
  background: white;
  color: var(--primary-color);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  transition: all var(--transition-base);
}

.overlay-btn:hover {
  transform: scale(1.1);
}

.project-content {
  padding: var(--spacing-lg);
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: start;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
}

.project-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.3;
}

.project-badge {
  padding: 0.25rem 0.75rem;
  background: var(--primary-color);
  color: white;
  border-radius: var(--radius-full);
  font-size: var(--fs-xs);
  font-weight: 600;
  white-space: nowrap;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.project-tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-bottom: var(--spacing-md);
}

.tech-tag {
  padding: 0.25rem 0.75rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  font-size: var(--fs-xs);
  color: var(--text-secondary);
  font-weight: 500;
}

.project-description {
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: var(--spacing-md);
  font-size: var(--fs-sm);
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-bottom: var(--spacing-md);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--border-color);
}

.category-tag {
  padding: 0.25rem 0.75rem;
  background: var(--bg-tertiary);
  border-radius: var(--radius-full);
  font-size: var(--fs-xs);
  color: var(--text-muted);
  font-weight: 500;
}

.project-link-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  color: var(--primary-color);
  font-weight: 600;
  font-size: var(--fs-sm);
  transition: gap var(--transition-base);
}

.project-link-btn:hover {
  gap: var(--spacing-sm);
}

/*=============== CONTACT PAGE ===============*/
.contact-content {
  padding: var(--spacing-3xl) 0;
}

.contact-wrapper {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: var(--spacing-3xl);
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.contact-card {
  padding: var(--spacing-lg);
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
}

.contact-card:hover {
  border-color: var(--primary-color);
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.contact-card-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.contact-card-header i {
  font-size: 1.5rem;
  color: var(--primary-color);
}

.contact-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
}

.contact-card p,
.contact-card a {
  color: var(--text-secondary);
  font-size: var(--fs-sm);
  line-height: 1.6;
}

.contact-card a:hover {
  color: var(--primary-color);
}

.contact-form-container {
  padding: var(--spacing-xl);
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
}

.contact-form-container h2 {
  font-size: var(--fs-md);
  margin-bottom: var(--spacing-lg);
  font-weight: 600;
}

.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-group label {
  display: block;
  margin-bottom: var(--spacing-xs);
  font-weight: 500;
  color: var(--text-primary);
  font-size: var(--fs-sm);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 0.875rem 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: var(--fs-base);
  transition: all var(--transition-base);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary-color);
  background: white;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group textarea {
  resize: vertical;
  min-height: 150px;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--text-muted);
}

.submit-btn {
  width: 100%;
  padding: 1rem;
  background: var(--primary-color);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-base);
  box-shadow: var(--shadow-md);
}

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

.submit-btn:active {
  transform: translateY(0);
}

/*=============== PROJECTS PAGE - HIDE SPECIFIC PROJECTS ===============*/
.project-card:has(.project-title:contains("Credit Score Classification")),
.project-card:has(.project-title:contains("Food Delivery Time Prediction")),
.project-card:has(.project-title:contains("YUMM-YUMM")) {
  display: none !important;
}

/* Alternative approach - hide by data-category if needed */
.project-card[data-category*="credit"],
.project-card[data-category*="food"],
.project-card[data-category*="yumm"] {
  display: none !important;
}

/*=============== FOOTER ===============*/
.footer {
  padding: var(--spacing-3xl) 0 var(--spacing-lg);
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: var(--spacing-3xl);
  margin-bottom: var(--spacing-xl);
}

.footer-brand .footer-logo {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: var(--spacing-sm);
  display: inline-block;
}

.footer-brand p {
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: 400px;
  font-size: var(--fs-sm);
}

.footer-column h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

.footer-column a {
  display: block;
  color: var(--text-secondary);
  font-size: var(--fs-sm);
  margin-bottom: var(--spacing-sm);
  transition: all var(--transition-base);
}

.footer-column a:hover {
  color: var(--primary-color);
  padding-left: var(--spacing-xs);
}

.footer-bottom {
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border-color);
  text-align: center;
}

.footer-bottom p {
  color: var(--text-muted);
  font-size: var(--fs-sm);
  margin: 0;
}

/*=============== SCROLL UP ===============*/
.scroll-top {
  position: fixed;
  right: var(--spacing-lg);
  bottom: -50px;
  width: 48px;
  height: 48px;
  background: var(--primary-color);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  box-shadow: var(--shadow-lg);
  z-index: var(--z-tooltip);
  transition: all var(--transition-base);
  border: none;
}

.scroll-top:hover {
  transform: translateY(-5px);
  background: var(--primary-dark);
}

.scroll-top.show-scroll {
  bottom: var(--spacing-lg);
}

/*=============== SCROLLBAR ===============*/
::-webkit-scrollbar {
  width: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--primary-color);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--primary-dark);
}

/*=============== RESPONSIVE ===============*/
@media (max-width: 1024px) {
  .hero-content {
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
  }
  
  .hero-visual {
    height: 400px;
  }
  
  .about-grid {
    grid-template-columns: 1fr;
  }
  
  .contact-wrapper {
    grid-template-columns: 1fr;
  }
  
  .footer-content {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
  }
}

@media (max-width: 768px) {
  :root {
    --fs-xl: 2.5rem;
    --fs-lg: 2rem;
    --fs-md: 1.5rem;
  }
  
  .nav__list {
    position: fixed;
    top: 0;
    right: -100%;
    width: 75%;
    height: 100vh;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    padding: var(--spacing-3xl) var(--spacing-xl);
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-lg);
    transition: right var(--transition-base);
    box-shadow: var(--shadow-xl);
    border-left: 1px solid var(--border-color);
  }
  
  .nav__list.show-menu {
    right: 0;
  }
  
  .nav__toggle,
  .nav__close {
    display: block;
    font-size: 1.5rem;
    color: var(--text-primary);
    cursor: pointer;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
  }
  
  .nav__toggle:hover,
  .nav__close:hover {
    background: var(--bg-secondary);
  }
  
  .nav__close {
    position: absolute;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
  }
  
  .hero-stats {
    grid-template-columns: 1fr;
    gap: var(--spacing-md);
  }
  
  .hero-buttons {
    flex-direction: column;
  }
  
  .btn {
    width: 100%;
  }
  
  .projects-showcase,
  .projects-grid {
    grid-template-columns: 1fr;
  }
  
  .skills-detailed,
  .publications-grid {
    grid-template-columns: 1fr;
  }
  
  .timeline {
    padding-left: var(--spacing-xl);
  }
  
  .timeline-icon {
    left: calc(-1 * var(--spacing-xl) - 22px);
    width: 40px;
    height: 40px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-md);
  }
  
  .hero-section {
    padding-top: calc(var(--header-height) + var(--spacing-lg));
  }
  
  .hero-visual {
    height: 300px;
  }
  
  .floating-card {
    padding: var(--spacing-sm) var(--spacing-md);
  }
  
  .floating-card span {
    font-size: var(--fs-sm);
  }
  
  .filter-tabs {
    gap: var(--spacing-xs);
  }
  
  .filter-btn {
    padding: 0.625rem 1.25rem;
    font-size: var(--fs-xs);
  }
  
  .stats-grid {
    grid-template-columns: 1fr;
  }
}