/* ===================================================================
   Design System & CSS Custom Properties (Variables)
   =================================================================== */
:root {
  /* Light Theme Colors */
  --bg-primary: #f8fafc;
  --bg-card: #ffffff;
  --bg-card-hover: #f1f5f9;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  
  --accent-primary: #2563eb;       /* Royal Blue */
  --accent-hover: #1d4ed8;
  --accent-light: #eff6ff;
  --accent-border: #bfdbfe;
  
  --tag-eda-bg: #fef3c7;
  --tag-eda-text: #92400e;
  --tag-ml-bg: #ede9fe;
  --tag-ml-text: #5b21b6;
  
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', Menlo, Monaco, Courier, monospace;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  /* Dark Theme Colors */
  --bg-primary: #0b0f19;
  --bg-card: #111827;
  --bg-card-hover: #1f2937;
  --text-primary: #f9fafb;
  --text-secondary: #9ca3af;
  --text-muted: #6b7280;
  
  --accent-primary: #3b82f6;
  --accent-hover: #60a5fa;
  --accent-light: rgba(59, 130, 246, 0.15);
  --accent-border: rgba(59, 130, 246, 0.3);
  
  --tag-eda-bg: rgba(245, 158, 11, 0.2);
  --tag-eda-text: #fcd34d;
  --tag-ml-bg: rgba(139, 92, 246, 0.2);
  --tag-ml-text: #c4b5fd;
  
  --border-color: #1f2937;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.5);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.3);
  --shadow-lg: 0 10px 20px -3px rgb(0 0 0 / 0.5);
}

/* Base Reset & Typography */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
  -webkit-font-smoothing: antialiased;
}

code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background-color: var(--accent-light);
  color: var(--accent-primary);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
}

/* Layout Container */
.container {
  max-width: 1040px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Navbar */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(var(--bg-card), 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition);
}

.nav-container {
  max-width: 1040px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--accent-primary);
  text-decoration: none;
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  gap: 24px;
}

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

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

.btn-icon {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 38px;
  height: 38px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  transition: var(--transition);
}

.btn-icon:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent-primary);
  transform: scale(1.05);
}

/* Hero Section */
.hero-section {
  padding: 64px 0 48px;
  border-bottom: 1px solid var(--border-color);
}

.badge-status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--accent-light);
  color: var(--accent-primary);
  border: 1px solid var(--accent-border);
  padding: 4px 12px;
  border-radius: 9999px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 20px;
}

.status-dot {
  width: 8px;
  height: 8px;
  background-color: #10b981;
  border-radius: 50%;
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.2);
  display: inline-block;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); opacity: 0.8; }
  50% { transform: scale(1.15); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.8; }
}

.hero-title {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -1px;
  line-height: 1.15;
  margin-bottom: 8px;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--accent-primary);
  font-weight: 600;
  margin-bottom: 16px;
}

.hero-bio {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 800px;
  margin-bottom: 28px;
}

.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.contact-item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  padding: 6px 14px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

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

.icon-svg {
  width: 18px;
  height: 18px;
}

/* Sections Common Styling */
.section {
  padding: 60px 0;
}

.section-header {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-bottom: 32px;
}

.section-title {
  font-size: 1.85rem;
  font-weight: 700;
  letter-spacing: -0.5px;
  white-space: nowrap;
}

.section-line {
  flex-grow: 1;
  height: 1px;
  background-color: var(--border-color);
}

/* Cards */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--accent-border);
}

.cards-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 12px;
  gap: 16px;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.card-subtitle {
  font-size: 1rem;
  color: var(--accent-primary);
  font-weight: 500;
}

.card-date {
  font-size: 0.88rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  white-space: nowrap;
  background: var(--bg-primary);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

/* Education Specific */
.gpa-pill {
  display: inline-block;
  background: var(--accent-light);
  color: var(--accent-primary);
  font-size: 0.88rem;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  margin-bottom: 14px;
}

.edu-detail p {
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.coursework {
  margin-top: 10px;
}

.coursework strong {
  display: block;
  font-size: 0.9rem;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.tags-container {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.82rem;
  padding: 3px 10px;
  border-radius: 9999px;
  font-weight: 500;
}

.edu-note {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-top: 8px;
}

/* Filter Tabs for Projects */
.filter-tabs {
  display: flex;
  gap: 12px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.filter-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 8px 18px;
  border-radius: 9999px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

.filter-btn:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.filter-btn.active {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.3);
}

/* Projects Grid */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(310px, 1fr));
  gap: 20px;
}

.project-card {
  display: flex;
  flex-direction: column;
}

.project-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.project-tag {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 3px 10px;
  border-radius: var(--radius-sm);
}

.project-tag.eda {
  background: var(--tag-eda-bg);
  color: var(--tag-eda-text);
}

.project-tag.ml {
  background: var(--tag-ml-bg);
  color: var(--tag-ml-text);
}

.project-date {
  font-size: 0.82rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
}

.project-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 6px;
  line-height: 1.3;
}

.tech-stack {
  margin-bottom: 14px;
  font-size: 0.88rem;
}

.project-highlights {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: auto;
}

.project-highlights li {
  position: relative;
  padding-left: 18px;
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.project-highlights li::before {
  content: "▹";
  position: absolute;
  left: 0;
  color: var(--accent-primary);
  font-weight: bold;
}

/* Experience Timeline */
.timeline {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.timeline::before {
  content: "";
  position: absolute;
  top: 14px;
  bottom: 14px;
  left: 11px;
  width: 2px;
  background-color: var(--border-color);
}

.timeline-item {
  position: relative;
  display: flex;
  gap: 24px;
}

.timeline-dot {
  position: relative;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 3px solid var(--accent-primary);
  flex-shrink: 0;
  margin-top: 16px;
  z-index: 2;
}

.timeline-content {
  flex-grow: 1;
}

.job-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 12px;
}

.job-list li {
  position: relative;
  padding-left: 18px;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

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

/* Skills Section */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}

.skill-category {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 14px;
  color: var(--text-primary);
}

.tag-tech {
  background: var(--bg-primary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  font-size: 0.88rem;
  padding: 5px 12px;
  border-radius: var(--radius-sm);
  font-weight: 500;
  transition: var(--transition);
}

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

.tag-license {
  background: var(--accent-light);
  color: var(--accent-primary);
  border: 1px solid var(--accent-border);
  font-size: 0.88rem;
  padding: 5px 12px;
  border-radius: var(--radius-sm);
  font-weight: 600;
}

/* Footer */
.footer {
  margin-top: 80px;
  padding: 40px 0;
  border-top: 1px solid var(--border-color);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer-sub {
  font-size: 0.8rem;
  margin-top: 6px;
}

/* Responsive Media Queries (Mobile Friendliness) */
@media (max-width: 768px) {
  .hero-title {
    font-size: 2.3rem;
  }
  
  .nav-links {
    display: none; /* Can be expanded into hamburger menu */
  }
  
  .card-header {
    flex-direction: column;
    gap: 8px;
  }
  
  .card-date {
    align-self: flex-start;
  }
  
  .projects-grid {
    grid-template-columns: 1fr;
  }
  
  .timeline::before {
    left: 7px;
  }
  
  .timeline-dot {
    width: 16px;
    height: 16px;
    margin-top: 20px;
    border-width: 2px;
  }
}

/* Print Stylesheet (Ctrl/Cmd + P friendly) */
@media print {
  .navbar, .filter-tabs, .btn-icon, .footer {
    display: none !important;
  }
  body {
    background: #ffffff !important;
    color: #000000 !important;
    font-size: 11pt;
  }
  .card {
    border: none !important;
    box-shadow: none !important;
    padding: 10px 0 !important;
  }
}