/* Modern Design System & CSS Variables */
:root {
  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  
  /* Color Palette - Elegant Dark Mode */
  --bg-primary: #0b0f19;
  --bg-secondary: #161f30;
  --bg-tertiary: #1f2d44;
  --accent-primary: #3b82f6; /* Modern Blue */
  --accent-secondary: #10b981; /* Emerald green */
  --text-primary: #f3f4f6;
  --text-secondary: #9ca3af;
  --text-muted: #6b7280;
  --border-color: #2e3c54;
  
  /* Gradation & Shadows */
  --grad-primary: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
  --grad-glow: linear-gradient(135deg, rgba(59, 130, 246, 0.15) 0%, rgba(139, 92, 246, 0.15) 100%);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.4);
  
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  scroll-behavior: smooth;
}

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

/* Scrollbar styling */
::-webkit-scrollbar {
  width: 10px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--bg-tertiary);
  border-radius: 5px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--accent-primary);
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* Header & Navigation */
header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(11, 15, 25, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  transition: var(--transition-smooth);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
}

.logo {
  font-size: 1.4rem;
  font-weight: 800;
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-decoration: none;
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition-smooth);
}

.nav-links a:hover {
  color: var(--text-primary);
}

/* Hero Section */
.hero {
  padding: 160px 0 100px 0;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -10%;
  right: -10%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.2) 0%, transparent 70%);
  z-index: -1;
  filter: blur(40px);
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -10%;
  left: -10%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(139, 92, 246, 0.15) 0%, transparent 70%);
  z-index: -1;
  filter: blur(40px);
}

.hero-tag {
  display: inline-block;
  padding: 0.4rem 1rem;
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.25);
  color: var(--accent-primary);
  border-radius: 100px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 1.5rem;
  letter-spacing: -1px;
}

.hero h1 span {
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 700px;
  margin-bottom: 2.5rem;
}

.social-links {
  display: flex;
  gap: 1rem;
  align-items: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  text-decoration: none;
  font-size: 0.95rem;
  transition: var(--transition-smooth);
  cursor: pointer;
}

.btn-primary {
  background: var(--grad-primary);
  color: white;
  border: none;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(139, 92, 246, 0.4);
}

.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(--text-secondary);
}

/* Sections General */
section {
  padding: 80px 0;
  border-bottom: 1px solid var(--border-color);
}

.section-title {
  font-size: 2.2rem;
  font-weight: 800;
  margin-bottom: 3rem;
  position: relative;
  letter-spacing: -0.5px;
}

.section-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -10px;
  width: 50px;
  height: 4px;
  background: var(--grad-primary);
  border-radius: 2px;
}

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

.card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 2rem;
  border-radius: var(--radius-md);
  transition: var(--transition-smooth);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--grad-glow);
  opacity: 0;
  transition: var(--transition-smooth);
  z-index: 0;
  pointer-events: none;
}

.card:hover {
  transform: translateY(-5px);
  border-color: #4b5d78;
}

.card:hover::before {
  opacity: 1;
}

.card * {
  position: relative;
  z-index: 1;
}

.card h3 {
  font-size: 1.25rem;
  margin-bottom: 1rem;
}

/* Skills styling */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.skills-card h3 {
  color: var(--accent-primary);
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

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

.tag {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 500;
  border: 1px solid rgba(255, 255, 255, 0.05);
  transition: var(--transition-smooth);
}

.tag:hover {
  background: var(--accent-primary);
  border-color: var(--accent-primary);
  color: white;
}

/* Timeline/Experience Styling */
.timeline {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 31px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: var(--border-color);
}

.timeline-item {
  position: relative;
  padding-left: 70px;
  margin-bottom: 3.5rem;
}

.timeline-item:last-child {
  margin-bottom: 0;
}

.timeline-marker {
  position: absolute;
  left: 20px;
  top: 6px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--bg-primary);
  border: 4px solid var(--accent-primary);
  z-index: 2;
  transition: var(--transition-smooth);
}

.timeline-item:hover .timeline-marker {
  background: var(--accent-primary);
  box-shadow: 0 0 12px var(--accent-primary);
}

.timeline-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 2rem;
  border-radius: var(--radius-md);
  transition: var(--transition-smooth);
}

.timeline-content:hover {
  border-color: #4b5d78;
}

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

.timeline-title h3 {
  font-size: 1.3rem;
  font-weight: 700;
}

.timeline-company {
  color: var(--accent-secondary);
  font-weight: 600;
  font-size: 1rem;
}

.timeline-date {
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
}

.timeline-list {
  list-style-type: none;
}

.timeline-list li {
  position: relative;
  padding-left: 1.25rem;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.timeline-list li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--accent-primary);
  font-weight: bold;
}

.tech-stack-label {
  margin-top: 1.25rem;
  font-size: 0.9rem;
  color: var(--text-primary);
  font-weight: 600;
}

.tech-stack-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.tech-tag {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.08);
  font-size: 0.8rem;
  color: var(--text-secondary);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
}

/* Certifications list */
.certs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
}

.cert-card {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  padding: 1.5rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: var(--transition-smooth);
}

.cert-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-primary);
}

.cert-icon {
  font-size: 1.75rem;
  color: var(--accent-primary);
}

.cert-info h4 {
  font-size: 1rem;
  margin-bottom: 0.25rem;
}

.cert-info p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.cert-info a {
  color: var(--accent-primary);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  margin-top: 0.25rem;
}

.cert-info a:hover {
  text-decoration: underline;
}

/* Footer styling */
footer {
  padding: 40px 0;
  background: var(--bg-primary);
  border-top: 1px solid var(--border-color);
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

footer a {
  color: var(--text-primary);
  text-decoration: none;
  transition: var(--transition-smooth);
}

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

/* Responsive adjustments */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.5rem;
  }
  .nav-links {
    display: none; /* simple nav fallback or hide on mobile for simplicity */
  }
  .timeline::before {
    left: 15px;
  }
  .timeline-item {
    padding-left: 40px;
  }
  .timeline-marker {
    left: 4px;
  }
  .timeline-header {
    flex-direction: column;
  }
  .timeline-date {
    margin-top: 0.25rem;
  }
}