/* ==================== CSS Variables ==================== */
:root {
  /* Light Mode Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e9ecef;
  --text-primary: #1a1a1a;
  --text-secondary: #6c757d;
  --accent-primary: #2563eb;
  --accent-secondary: #3b82f6;
  --accent-gradient: linear-gradient(135deg, #2563eb 0%, #3b82f6 100%);
  --border-color: #dee2e6;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.12);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.16);
  --card-bg: #ffffff;
  --nav-bg: rgba(255, 255, 255, 0.9);
  
  /* Typography */
  --font-primary: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
  
  /* Transitions */
  --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Mode */
[data-theme="dark"] {
  --bg-primary: #0a0a0a;
  --bg-secondary: #141414;
  --bg-tertiary: #1e1e1e;
  --text-primary: #f5f5f5;
  --text-secondary: #a0a0a0;
  --accent-primary: #3b82f6;
  --accent-secondary: #60a5fa;
  --accent-gradient: linear-gradient(135deg, #3b82f6 0%, #60a5fa 100%);
  --border-color: #2a2a2a;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.6);
  --card-bg: #141414;
  --nav-bg: rgba(10, 10, 10, 0.9);
}

/* ==================== Base Styles ==================== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-primary);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color var(--transition-base), color var(--transition-base);
  overflow-x: hidden;
}

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

/* ==================== Theme Toggle ==================== */
.theme-toggle {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 2px solid var(--border-color);
  background-color: var(--card-bg);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-base);
  box-shadow: var(--shadow-sm);
  margin-left: 0.5rem;
}

.theme-toggle:hover {
  transform: scale(1.1);
  box-shadow: var(--shadow-md);
}

.sun-icon,
.moon-icon {
  position: absolute;
  transition: all var(--transition-base);
  color: var(--text-primary);
}

[data-theme="light"] .moon-icon,
[data-theme="dark"] .sun-icon {
  opacity: 0;
  transform: rotate(180deg) scale(0);
}

[data-theme="light"] .sun-icon,
[data-theme="dark"] .moon-icon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

/* ==================== Navigation ==================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 999;
  background-color: var(--nav-bg);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  transition: all var(--transition-base);
}

.navbar.scrolled {
  box-shadow: var(--shadow-sm);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  font-size: 1.5rem;
  font-weight: 700;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-decoration: none;
  transition: transform var(--transition-base);
}

.nav-logo:hover {
  transform: scale(1.05);
}

.nav-menu {
  display: flex;
  gap: 2rem;
  list-style: none;
  margin-left: auto;
  margin-right: 0.5rem;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition-base);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-gradient);
  transition: width var(--transition-base);
}

.nav-link:hover {
  color: var(--accent-primary);
}

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

/* ==================== Hero Section ==================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  padding: 5rem 2rem 3rem;
}

.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: -1;
}

.grid-pattern {
  width: 100%;
  height: 100%;
  background-image: 
    linear-gradient(var(--border-color) 1px, transparent 1px),
    linear-gradient(90deg, var(--border-color) 1px, transparent 1px);
  background-size: 50px 50px;
  opacity: 0.3;
  animation: gridMove 20s linear infinite;
}

@keyframes gridMove {
  0% {
    transform: translate(0, 0);
  }
  100% {
    transform: translate(50px, 50px);
  }
}

.hero-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1;
  width: 100%;
  max-width: 800px;
}

.hero-content {
  max-width: 800px;
  text-align: center;
  width: 100%;
}

.hero-profile {
  display: flex;
  justify-content: center;
  margin-bottom: 1rem;
}

.hero-profile-img {
  width: 220px;
  height: 220px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--border-color);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.12);
  background-color: var(--bg-tertiary);
}

.hero-content .hero-badge {
  margin-bottom: 2rem;
}

.hero-badge {
  display: inline-block;
  padding: 0.5rem 1rem;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 50px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--accent-primary);
  margin-bottom: 2rem;
  animation: fadeInDown 0.8s ease-out;
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 700;
  margin-bottom: 1rem;
  line-height: 1.2;
  animation: fadeInUp 0.8s ease-out 0.2s both;
}

.gradient-text {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  min-height: 2.5rem;
  font-family: var(--font-mono);
  animation: fadeInUp 0.8s ease-out 0.4s both;
}

.cursor {
  animation: blink 1s infinite;
  color: var(--accent-primary);
}

@keyframes blink {
  0%, 50% { opacity: 1; }
  51%, 100% { opacity: 0; }
}

.hero-description {
  font-size: 1.125rem;
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  line-height: 1.8;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  animation: fadeInUp 0.8s ease-out 0.6s both;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 3rem;
  animation: fadeInUp 0.8s ease-out 0.8s both;
}

.btn {
  padding: 0.875rem 2rem;
  border-radius: 8px;
  font-weight: 600;
  text-decoration: none;
  transition: all var(--transition-base);
  border: 2px solid transparent;
  font-size: 1rem;
  cursor: pointer;
}

.btn-primary {
  background: var(--accent-gradient);
  color: white;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.4);
}

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

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

.hero-socials {
  display: flex;
  gap: 1rem;
  justify-content: center;
  animation: fadeInUp 0.8s ease-out 1s both;
}

.social-link {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--border-color);
  border-radius: 50%;
  color: var(--text-secondary);
  transition: all var(--transition-base);
  background-color: var(--card-bg);
}

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

.scroll-indicator {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  animation: fadeIn 1s ease-out 1.5s both;
}

.mouse {
  width: 24px;
  height: 40px;
  border: 2px solid var(--text-secondary);
  border-radius: 12px;
  position: relative;
}

.wheel {
  width: 4px;
  height: 8px;
  background-color: var(--text-secondary);
  border-radius: 2px;
  position: absolute;
  top: 8px;
  left: 50%;
  transform: translateX(-50%);
  animation: scroll 2s infinite;
}

@keyframes scroll {
  0% { opacity: 1; top: 8px; }
  100% { opacity: 0; top: 20px; }
}

/* ==================== Sections ==================== */
.section {
  padding: 6rem 2rem;
}

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

.section-title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: 4rem;
  position: relative;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -1rem;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 4px;
  background: var(--accent-gradient);
  border-radius: 2px;
}

/* ==================== About Section ==================== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: start;
}

.about-text {
  font-size: 1.125rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  line-height: 1.8;
}

.about-highlights {
  margin-top: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.highlight-item {
  display: flex;
  gap: 1rem;
  align-items: center;
  padding: 1.5rem;
  background-color: var(--bg-secondary);
  border-radius: 12px;
  border: 1px solid var(--border-color);
  transition: all var(--transition-base);
}

.highlight-item:hover {
  transform: translateX(8px);
  box-shadow: var(--shadow-md);
}

.highlight-icon {
  font-size: 2rem;
}

.highlight-content h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.highlight-content p {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.about-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

.stat-card {
  background-color: var(--card-bg);
  border: 2px solid var(--border-color);
  border-radius: 16px;
  padding: 2rem;
  text-align: center;
  transition: all var(--transition-base);
}

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

.stat-number {
  font-size: 3rem;
  font-weight: 700;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 0.5rem;
}

.stat-label {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
}

/* ==================== Experience Section ==================== */
.experience {
  background-color: var(--bg-secondary);
}

.timeline {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
}

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

.timeline-item {
  position: relative;
  padding-left: 3rem;
  margin-bottom: 3rem;
}

.timeline-marker {
  position: absolute;
  left: -6px;
  top: 8px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent-gradient);
  border: 3px solid var(--bg-secondary);
  transition: all var(--transition-base);
}

.timeline-item:hover .timeline-marker {
  transform: scale(1.5);
}

.timeline-content {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 2rem;
  transition: all var(--transition-base);
}

.timeline-content:hover {
  transform: translateX(8px);
  box-shadow: var(--shadow-md);
}

.timeline-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 0.5rem;
  gap: 1rem;
  flex-wrap: wrap;
}

.timeline-header h3 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.timeline-header h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--accent-primary);
  margin-top: 0.25rem;
}

.timeline-date {
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-weight: 500;
  white-space: nowrap;
}

.timeline-location {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.timeline-details {
  list-style: none;
  margin-bottom: 1rem;
}

.timeline-details li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.timeline-details li::before {
  content: '▹';
  position: absolute;
  left: 0;
  color: var(--accent-primary);
  font-weight: 700;
}

.timeline-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tag {
  padding: 0.25rem 0.75rem;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--accent-primary);
  transition: all var(--transition-base);
}

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

/* ==================== Projects Section ==================== */
.projects-filter {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 3rem;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 0.625rem 1.5rem;
  border: 2px solid var(--border-color);
  background-color: transparent;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-base);
  color: var(--text-secondary);
  font-family: var(--font-primary);
  font-size: 0.875rem;
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--accent-gradient);
  color: white;
  border-color: transparent;
  transform: translateY(-2px);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.project-card {
  background-color: var(--card-bg);
  border: 2px solid var(--border-color);
  border-radius: 16px;
  padding: 2rem;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.project-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--accent-gradient);
  transform: scaleX(0);
  transition: transform var(--transition-base);
}

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

.project-card:hover::before {
  transform: scaleX(1);
}

.project-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.project-award {
  display: inline-block;
  padding: 0.375rem 0.75rem;
  background-color: #fef3c7;
  color: #92400e;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

[data-theme="dark"] .project-award {
  background-color: #422006;
  color: #fbbf24;
}

.project-card h3 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.project-card p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  line-height: 1.7;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.tech-tag {
  padding: 0.375rem 0.875rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: all var(--transition-base);
}

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

.project-links {
  display: flex;
  gap: 1rem;
}

.project-link {
  color: var(--accent-primary);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.875rem;
  transition: all var(--transition-base);
}

.project-link:hover {
  color: var(--accent-secondary);
  transform: translateX(4px);
}

.project-card.hidden {
  display: none;
}

/* ==================== Skills Section ==================== */
.skills {
  background-color: var(--bg-secondary);
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.skill-category {
  background-color: var(--card-bg);
  border: 2px solid var(--border-color);
  border-radius: 16px;
  padding: 2rem;
  transition: all var(--transition-base);
}

.skill-category:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-primary);
}

.skill-category-title {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
}

.skill-icon {
  font-size: 1.5rem;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.skill-tag {
  padding: 0.5rem 1rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition-base);
}

.skill-tag:hover {
  background: var(--accent-gradient);
  color: white;
  transform: translateY(-3px);
  box-shadow: var(--shadow-sm);
}

/* ==================== Contact Section ==================== */
.contact-description {
  text-align: center;
  font-size: 1.125rem;
  color: var(--text-secondary);
  margin-bottom: 3rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

.contact-card {
  background-color: var(--card-bg);
  border: 2px solid var(--border-color);
  border-radius: 16px;
  padding: 2rem;
  text-align: center;
  transition: all var(--transition-base);
  text-decoration: none;
  color: inherit;
}

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

.contact-icon {
  width: 60px;
  height: 60px;
  margin: 0 auto 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-gradient);
  border-radius: 50%;
  color: white;
}

.contact-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.contact-card p {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* ==================== Footer ==================== */
.footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 2rem;
  text-align: center;
}

.footer p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition-base);
}

.footer-links a:hover {
  color: var(--accent-primary);
}

/* ==================== Animations ==================== */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

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

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

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

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ==================== Responsive Design ==================== */
@media (max-width: 768px) {
  .nav-container {
    padding: 1rem 1.5rem;
  }
  
  .nav-menu {
    gap: 1rem;
    font-size: 0.875rem;
  }
  
  .about-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  
  .about-stats {
    grid-template-columns: 1fr 1fr;
  }
  
  .timeline::before {
    left: 8px;
  }
  
  .timeline-item {
    padding-left: 2.5rem;
  }
  
  .timeline-header {
    flex-direction: column;
  }
  
  .projects-grid {
    grid-template-columns: 1fr;
  }
  
  .skills-grid {
    grid-template-columns: 1fr;
  }
  
  .contact-grid {
    grid-template-columns: 1fr;
  }
  
  .section {
    padding: 4rem 1.5rem;
  }
  
  .container {
    padding: 0 1.5rem;
  }
  
  .hero {
    padding: 5rem 1.5rem 3rem;
  }
  
  .hero-inner,
  .hero-content {
    max-width: 100%;
    padding: 0 1.5rem;
  }
  
  .hero-profile-img {
    width: 180px;
    height: 180px;
  }
}

@media (max-width: 480px) {
  .nav-container {
    padding: 1rem 1rem;
  }
  
  .nav-menu {
    gap: 0.5rem;
    font-size: 0.75rem;
  }
  
  .theme-toggle {
    width: 40px;
    height: 40px;
  }
  
  .hero-inner,
  .hero-content {
    padding: 0 1rem;
  }
  
  .hero-cta {
    flex-direction: column;
  }
  
  .btn {
    width: 100%;
  }
  
  .stat-number {
    font-size: 2.5rem;
  }
  
  .about-stats {
    grid-template-columns: 1fr;
  }
}