/* ============================================
   SAIKAT BANDYOPADHYAY — PORTFOLIO STYLES
   Design: Bold Modern Gradient + Glassmorphism
   ============================================ */

/* ---- CSS Custom Properties ---- */
:root {
  /* Gradient palette */
  --gradient-start: #6366f1;
  --gradient-mid: #8b5cf6;
  --gradient-end: #a855f7;
  --accent: #06b6d4;
  --accent-glow: rgba(6, 182, 212, 0.3);

  /* Surfaces */
  --bg-primary: #0f0f23;
  --bg-secondary: #1a1a3e;
  --bg-card: rgba(255, 255, 255, 0.05);
  --bg-card-hover: rgba(255, 255, 255, 0.1);

  /* Glass effect */
  --glass-bg: rgba(255, 255, 255, 0.06);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
  --glass-blur: blur(12px);

  /* Typography */
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-accent: #06b6d4;
  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing scale (8px base) */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 2rem;
  --space-xl: 4rem;
  --space-2xl: 8rem;

  /* Border radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;

  /* 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);
}

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

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

body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---- Accessibility ---- */
.skip-nav {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  padding: 0.75rem 1.5rem;
  background: var(--accent);
  color: var(--bg-primary);
  border-radius: var(--radius-md);
  font-weight: 600;
  z-index: 10000;
  transition: top var(--transition-fast);
  text-decoration: none;
}

.skip-nav:focus {
  top: 1rem;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

/* ---- Reduced Motion ---- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  #hero-canvas { display: none; }
}

/* ---- Utility Classes ---- */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

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

.glass-card {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--glass-shadow);
  transition: transform var(--transition-base),
              box-shadow var(--transition-base),
              border-color var(--transition-base);
}

.glass-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
  border-color: var(--accent);
}

.tech-badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: var(--accent);
  background: rgba(6, 182, 212, 0.1);
  border: 1px solid rgba(6, 182, 212, 0.2);
  border-radius: 9999px;
  letter-spacing: 0.025em;
}

/* ---- Three.js Canvas ---- */
#hero-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  pointer-events: none;
}

/* ---- Navigation ---- */
.main-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  padding: var(--space-md) 0;
  transition: background var(--transition-base),
              backdrop-filter var(--transition-base),
              padding var(--transition-base);
}

.main-nav.nav-scrolled {
  background: rgba(15, 15, 35, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--glass-border);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  font-size: 1.5rem;
  font-weight: 800;
  text-decoration: none;
  letter-spacing: -0.025em;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: var(--space-lg);
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.025em;
  transition: color var(--transition-fast);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--gradient-start), var(--accent));
  transition: width var(--transition-base);
}

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

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

/* Mobile menu button */
.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  z-index: 1001;
}

.hamburger-line {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.mobile-menu-btn.active .hamburger-line:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.mobile-menu-btn.active .hamburger-line:nth-child(2) {
  opacity: 0;
}

.mobile-menu-btn.active .hamburger-line:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ---- Hero Section ---- */
.hero-section {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: var(--space-2xl) var(--space-lg);
  position: relative;
}

.hero-content {
  max-width: 800px;
}

.hero-greeting {
  font-size: 1.125rem;
  color: var(--accent);
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: var(--space-sm);
}

.hero-name {
  font-size: clamp(2.5rem, 8vw, 5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: var(--space-md);
}

.hero-typed-wrapper {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
  min-height: 2.5rem;
}

.hero-typed-prefix {
  color: var(--text-secondary);
}

#typed-output {
  color: var(--accent);
  font-weight: 600;
}

.typed-cursor {
  color: var(--accent);
  font-weight: 300;
}

.hero-tagline {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto var(--space-xl);
  line-height: 1.8;
  font-style: italic;
}

.hero-cta-group {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.875rem 2rem;
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-mid));
  color: white;
  text-decoration: none;
  border-radius: 9999px;
  font-weight: 600;
  font-size: 1rem;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.hero-cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(99, 102, 241, 0.5);
}

.hero-cta-secondary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.875rem 2rem;
  background: transparent;
  color: var(--text-primary);
  text-decoration: none;
  border-radius: 9999px;
  font-weight: 600;
  font-size: 1rem;
  border: 1px solid var(--glass-border);
  transition: border-color var(--transition-base), background var(--transition-base);
}

.hero-cta-secondary:hover {
  border-color: var(--accent);
  background: rgba(6, 182, 212, 0.05);
}

/* Scroll indicator */
.hero-scroll-indicator {
  position: absolute;
  bottom: 2rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-secondary);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  animation: fadeInUp 1s ease 1.5s both;
}

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

.scroll-wheel {
  width: 3px;
  height: 8px;
  background: var(--accent);
  border-radius: 2px;
  position: absolute;
  top: 6px;
  left: 50%;
  transform: translateX(-50%);
  animation: scrollWheel 2s ease-in-out infinite;
}

@keyframes scrollWheel {
  0%, 100% { opacity: 1; transform: translateX(-50%) translateY(0); }
  50% { opacity: 0.3; transform: translateX(-50%) translateY(12px); }
}

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

/* ---- Section Base ---- */
.section {
  padding: var(--space-2xl) 0;
  position: relative;
}

.section-heading {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-sm);
}

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

/* ---- About Section ---- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-xl);
}

.about-text {
  color: var(--text-secondary);
  font-size: 1.0625rem;
  line-height: 1.8;
  margin-bottom: var(--space-md);
}

.accent-quote {
  color: var(--accent);
  font-style: italic;
  font-size: 1.125rem;
  border-left: 3px solid var(--gradient-mid);
  padding-left: var(--space-md);
  margin-top: var(--space-lg);
}

.about-highlights {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}

.highlight-card {
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.highlight-card-header {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.highlight-icon {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(6, 182, 212, 0.1);
  border-radius: var(--radius-md);
  color: var(--accent);
}

.highlight-label {
  font-size: 0.8125rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.075em;
  color: var(--accent);
  margin-bottom: var(--space-xs);
}

.highlight-value {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.6;
}

/* ---- Project Timeline Visualization ---- */
.project-timeline-wrapper {
  position: relative;
  margin-bottom: var(--space-xl);
  padding: var(--space-lg) 0;
}

.timeline-axis {
  position: relative;
  width: 100%;
}

.timeline-years {
  display: flex;
  justify-content: space-between;
  padding: 0 var(--space-sm);
  margin-bottom: var(--space-sm);
}

.timeline-years .year-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
  letter-spacing: 0.05em;
}

.timeline-track {
  position: relative;
  width: 100%;
  height: 140px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  overflow: visible;
}

.timeline-block {
  position: absolute;
  height: 28px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), filter var(--transition-fast);
  display: flex;
  align-items: center;
  padding: 0 var(--space-sm);
  overflow: hidden;
  white-space: nowrap;
}

.timeline-block:hover {
  transform: scaleY(1.3);
  box-shadow: 0 0 20px rgba(6, 182, 212, 0.4);
  z-index: 10;
  filter: brightness(1.2);
}

.timeline-block-label {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  color: var(--text-primary);
  font-weight: 500;
  letter-spacing: 0.02em;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.5);
  pointer-events: none;
}

.timeline-tooltip {
  display: none;
  position: absolute;
  top: -10px;
  left: 50%;
  transform: translate(-50%, -100%);
  background: var(--bg-secondary);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--space-md) var(--space-lg);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.5);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  z-index: 100;
  width: 280px;
  pointer-events: none;
}

.timeline-tooltip.visible {
  display: block;
}

.tooltip-header {
  margin-bottom: var(--space-sm);
  text-align: center;
}

.tooltip-title {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0 0 0.25rem 0;
  line-height: 1.3;
}

.tooltip-period {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--text-accent);
}

#tooltip-donut {
  display: block;
  margin: var(--space-sm) auto;
  width: 160px;
  height: 160px;
}

.tooltip-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
  justify-content: center;
  min-height: 40px;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.6875rem;
  color: var(--text-secondary);
}

.legend-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* ---- Timeline Annotation Layer ---- */
.timeline-annotations {
  position: relative;
  width: 100%;
  height: 28px;
  margin-top: var(--space-sm);
}

.annotation-bar {
  position: absolute;
  height: 100%;
  border: 1px solid;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  padding: 0 0.5rem;
  overflow: hidden;
}

.annotation-label {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  font-weight: 400;
  letter-spacing: 0.01em;
  line-height: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ---- Projects Section ---- */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

.project-card {
  padding: var(--space-lg);
  position: relative;
  overflow: hidden;
}

.project-badge {
  position: absolute;
  top: var(--space-md);
  right: var(--space-md);
  padding: 0.2rem 0.75rem;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--bg-primary);
  background: linear-gradient(135deg, var(--gradient-start), var(--accent));
  border-radius: 9999px;
}

.featured-project {
  border-color: rgba(99, 102, 241, 0.3);
}

.featured-project::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--gradient-start), var(--gradient-mid), var(--accent));
}

.project-header {
  margin-bottom: var(--space-md);
}

.project-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.4;
}

.project-desc {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.7;
  margin-bottom: var(--space-md);
}

.project-outcome {
  color: var(--text-secondary);
  font-size: 0.875rem;
  line-height: 1.6;
  margin-bottom: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  background: rgba(6, 182, 212, 0.05);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--accent);
}

.project-outcome strong {
  color: var(--accent);
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

/* ---- Skills Section ---- */
.skills-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}

.skill-group {
  padding: var(--space-lg);
}

.skill-group-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-md);
  position: relative;
  padding-bottom: var(--space-sm);
}

.skill-group-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 40px;
  height: 2px;
  background: linear-gradient(90deg, var(--gradient-start), var(--accent));
}

.skill-badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

/* ---- Experience / Timeline ---- */
.timeline {
  position: relative;
  padding-left: 2rem;
}

.timeline::before {
  content: '';
  position: absolute;
  top: 0;
  left: 7px;
  width: 2px;
  height: 100%;
  background: linear-gradient(
    180deg,
    var(--gradient-start),
    var(--gradient-mid),
    var(--gradient-end),
    var(--accent),
    transparent
  );
}

.timeline-item {
  position: relative;
  padding-bottom: var(--space-xl);
}

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

.timeline-marker {
  position: absolute;
  left: -2rem;
  top: 1.5rem;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--bg-primary);
  border: 3px solid var(--accent);
  z-index: 1;
  box-shadow: 0 0 12px var(--accent-glow);
}

.timeline-card {
  padding: var(--space-lg);
}

.timeline-header {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  margin-bottom: var(--space-sm);
}

.timeline-role {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
}

.timeline-period {
  font-size: 0.8125rem;
  font-family: var(--font-mono);
  color: var(--accent);
}

.timeline-company {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  margin-bottom: var(--space-md);
}

.timeline-bullets {
  list-style: none;
  padding: 0;
}

.timeline-bullets li {
  color: var(--text-secondary);
  font-size: 0.875rem;
  line-height: 1.7;
  padding-left: 1.25rem;
  position: relative;
  margin-bottom: var(--space-sm);
}

.timeline-bullets li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--gradient-mid);
}

/* ---- Publications Section ---- */
.publications-list {
  display: grid;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.publication-card {
  padding: var(--space-lg);
  display: flex;
  gap: var(--space-lg);
  align-items: flex-start;
}

.pub-year {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent);
  flex-shrink: 0;
  min-width: 60px;
}

.pub-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.5;
  margin-bottom: var(--space-xs);
}

.pub-journal {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-xs);
}

.pub-doi {
  font-size: 0.8125rem;
  font-family: var(--font-mono);
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.pub-doi:hover {
  color: var(--text-primary);
}

/* Awards */
.awards-section {
  margin-top: var(--space-2xl);
}

.awards-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-lg);
}

.awards-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}

.award-card {
  padding: var(--space-md) var(--space-lg);
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.award-icon {
  color: var(--accent);
  font-size: 1.25rem;
  flex-shrink: 0;
}

.award-text {
  color: var(--text-secondary);
  font-size: 0.9375rem;
}

/* ---- Contact Form ---- */
.contact-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
  max-width: 900px;
  margin: 0 auto;
}

.contact-form-card {
  padding: var(--space-xl);
}

.contact-form-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-lg);
}

.form-group {
  margin-bottom: var(--space-md);
}

.form-label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-sm);
}

.form-input {
  width: 100%;
  padding: 0.75rem 1rem;
  font-family: var(--font-body);
  font-size: 0.9375rem;
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-base), box-shadow var(--transition-base);
  outline: none;
}

.form-input::placeholder {
  color: rgba(148, 163, 184, 0.5);
}

.form-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.form-select {
  appearance: none;
  -webkit-appearance: none;
  cursor: pointer;
  background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%2394a3b8' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  padding-right: 2.5rem;
}

.form-select option {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.form-textarea {
  resize: vertical;
  min-height: 120px;
}

.form-submit {
  width: 100%;
  justify-content: center;
  border: none;
  cursor: pointer;
  font-family: var(--font-body);
  margin-top: var(--space-sm);
}

.form-note {
  text-align: center;
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: var(--space-sm);
  font-style: italic;
}

/* ---- Blog Empty State ---- */
.blog-empty-state {
  padding: var(--space-xl);
  text-align: center;
  grid-column: 1 / -1;
}

.blog-empty-text {
  color: var(--text-secondary);
  font-size: 1.0625rem;
  line-height: 1.7;
}

/* ---- Blog Preview Section ---- */
.blog-preview-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.blog-card {
  padding: var(--space-lg);
  text-decoration: none;
  display: block;
}

.blog-card-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-sm);
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

.reading-time {
  font-family: var(--font-mono);
  color: var(--accent);
}

.blog-card h3 {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
  line-height: 1.4;
}

.blog-card h3 a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast);
}

.blog-card h3 a:hover {
  color: var(--accent);
}

.blog-excerpt {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.6;
  margin-bottom: var(--space-md);
}

.blog-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.blog-view-all {
  text-align: center;
}

/* ---- Contact Section ---- */
.contact-grid {
  max-width: 600px;
  margin: 0 auto;
}

.contact-card {
  padding: var(--space-xl);
  text-align: center;
}

.contact-info {
  margin-bottom: var(--space-lg);
}

.contact-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--accent);
  text-decoration: none;
  font-size: 1rem;
  font-weight: 500;
  transition: color var(--transition-fast);
  margin-bottom: var(--space-lg);
}

.contact-link:hover {
  color: var(--text-primary);
}

.contact-social {
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  margin-top: var(--space-lg);
}

.social-icon {
  color: var(--text-secondary);
  transition: color var(--transition-fast), transform var(--transition-fast);
}

.social-icon:hover {
  color: var(--accent);
  transform: translateY(-2px);
}

.contact-closing {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  font-style: italic;
}

/* ---- Footer ---- */
.site-footer {
  padding: var(--space-lg) 0;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.8125rem;
  border-top: 1px solid var(--glass-border);
}

/* ============================================
   RESPONSIVE BREAKPOINTS
   ============================================ */

/* Tablet */
@media (min-width: 768px) {
  .about-grid {
    grid-template-columns: 1fr;
  }

  .about-highlights {
    grid-template-columns: repeat(2, 1fr);
  }

  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .featured-project {
    grid-column: 1 / -1;
  }

  .skills-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .awards-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .blog-preview-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .timeline-header {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }

  .contact-layout {
    grid-template-columns: 1.4fr 1fr;
    align-items: start;
  }
}

/* Desktop */
@media (min-width: 1024px) {
  .about-highlights {
    grid-template-columns: repeat(4, 1fr);
  }

  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .skills-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .awards-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .blog-preview-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .timeline {
    padding-left: 3rem;
  }
}

/* Mobile nav */
@media (max-width: 767px) {
  .mobile-menu-btn {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 75%;
    max-width: 320px;
    height: 100vh;
    background: rgba(15, 15, 35, 0.97);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: var(--space-xl);
    transition: right var(--transition-slow);
    border-left: 1px solid var(--glass-border);
  }

  .nav-links.active {
    right: 0;
  }

  .nav-link {
    font-size: 1.25rem;
  }

  .publication-card {
    flex-direction: column;
    gap: var(--space-sm);
  }

  .hero-scroll-indicator {
    display: none;
  }
}

/* ============================== */
/* SKILL NETWORK VISUALIZATION    */
/* ============================== */
.skill-network-wrapper {
  position: relative;
  width: 100%;
  height: 720px;
  margin: var(--space-xl) 0 0;
  background:
    radial-gradient(ellipse at center, rgba(6, 182, 212, 0.06), transparent 65%),
    linear-gradient(180deg, rgba(15, 23, 42, 0.45), rgba(15, 23, 42, 0.15));
  border: 1px solid rgba(6, 182, 212, 0.14);
  border-radius: var(--radius-lg);
  overflow: hidden;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.skill-network-svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

/* Spoke edges (hub → skill) */
.skill-network-svg .edge {
  stroke-width: 1.4;
  stroke-opacity: 0.55;
  transition: stroke-width 0.3s ease, stroke-opacity 0.3s ease, opacity 0.3s ease;
  pointer-events: none;
}

.skill-network-svg .edge.highlighted {
  stroke-width: 2.2;
  stroke-opacity: 0.95;
  opacity: 1;
}

.skill-network-svg .edge.dimmed {
  opacity: 0.07;
}

/* Inter-hub edges (hub ↔ hub) form the biological module backbone */
.skill-network-svg .interhub-edge {
  stroke: rgba(6, 182, 212, 0.32);
  stroke-width: 2;
  stroke-dasharray: 4 4;
  stroke-linecap: round;
  transition: stroke 0.3s ease, stroke-opacity 0.3s ease, opacity 0.3s ease;
  pointer-events: none;
}

.skill-network-svg .interhub-edge.dimmed {
  opacity: 0.08;
}

/* Node groups (container holds translate; animation lives on inner circle) */
.skill-network-svg .node {
  cursor: pointer;
  transition: opacity 0.3s ease;
}

.skill-network-svg .node.dimmed {
  opacity: 0.18;
}

/* Orbs — animate filter (glow) instead of transform so translate is preserved */
.skill-network-svg .orb {
  transition: filter 0.3s ease, stroke-width 0.3s ease;
}

@keyframes skillOrbGlow {
  0%, 100% { filter: drop-shadow(0 0 3px currentColor); }
  50%      { filter: drop-shadow(0 0 9px currentColor); }
}

@keyframes hubOrbGlow {
  0%, 100% { filter: drop-shadow(0 0 6px currentColor); }
  50%      { filter: drop-shadow(0 0 16px currentColor); }
}

.skill-network-svg .skill-orb {
  animation: skillOrbGlow 4s ease-in-out infinite;
}

.skill-network-svg .hub-orb {
  animation: hubOrbGlow 5s ease-in-out infinite;
}

/* Stagger the pulse so the network feels alive */
.skill-network-svg .node.skill-node:nth-of-type(4n) .skill-orb   { animation-delay: 0s; }
.skill-network-svg .node.skill-node:nth-of-type(4n+1) .skill-orb { animation-delay: 0.9s; }
.skill-network-svg .node.skill-node:nth-of-type(4n+2) .skill-orb { animation-delay: 1.8s; }
.skill-network-svg .node.skill-node:nth-of-type(4n+3) .skill-orb { animation-delay: 2.7s; }

/* Hover / highlighted state: stronger glow + brighter stroke */
.skill-network-svg .node:hover .orb,
.skill-network-svg .node.highlighted .orb {
  filter: brightness(1.3) drop-shadow(0 0 14px currentColor);
  stroke-width: 2.5;
}

/* Node labels — base rules (skill labels hidden; hub labels always visible) */
.skill-network-svg .node text {
  font-family: 'Inter', -apple-system, sans-serif;
  fill: rgba(226, 232, 240, 0.92);
  pointer-events: none;
  user-select: none;
  opacity: 0;
  transition: opacity 0.25s ease, fill 0.3s ease;
  paint-order: stroke;
  stroke: rgba(15, 23, 42, 0.85);
  stroke-width: 3px;
  stroke-linejoin: round;
}

/* Hub (module) labels are ALWAYS visible — they anchor the network */
.skill-network-svg .node.hub-node text {
  opacity: 1;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.02em;
  fill: #f8fafc;
}

/* Skill labels only appear when their module is actively hovered */
.skill-network-svg .node.highlighted text {
  opacity: 1;
}

.skill-network-svg .node.skill-node text {
  font-size: 10px;
  font-weight: 500;
  fill: rgba(226, 232, 240, 0.9);
}

/* When another module is hovered, dim this hub's label so focus stays on the
   highlighted module — but don't hide it entirely */
.skill-network-svg .node.hub-node.dimmed text {
  opacity: 0.32;
}

/* Tooltip */
.skill-network-tooltip {
  position: absolute;
  top: 0;
  left: 0;
  background: rgba(15, 23, 42, 0.95);
  border: 1px solid rgba(6, 182, 212, 0.35);
  border-radius: 8px;
  padding: 8px 12px;
  pointer-events: none;
  opacity: 0;
  transform: translate(-50%, -140%);
  transition: opacity 0.2s ease;
  font-size: 0.78rem;
  white-space: nowrap;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
  z-index: 5;
}

.skill-network-tooltip.visible {
  opacity: 1;
}

.skill-network-tooltip .tooltip-label {
  display: block;
  color: #f1f5f9;
  font-weight: 600;
}

.skill-network-tooltip .tooltip-sub {
  display: block;
  color: rgba(148, 163, 184, 0.85);
  font-size: 0.68rem;
  margin-top: 2px;
}

/* Legend */
.skill-network-legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 10px 22px;
  margin: var(--space-md) auto 0;
  max-width: 960px;
  padding: 12px 22px;
  background: rgba(15, 23, 42, 0.55);
  border: 1px solid rgba(6, 182, 212, 0.18);
  border-radius: 999px;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: 0 4px 24px rgba(6, 182, 212, 0.06);
}

.skill-network-legend .legend-item {
  display: flex;
  align-items: center;
  gap: 7px;
  font-size: 0.72rem;
  font-weight: 500;
  color: rgba(203, 213, 225, 0.92);
  cursor: pointer;
  transition: color 0.2s ease, transform 0.2s ease;
}

.skill-network-legend .legend-item:hover {
  color: #f1f5f9;
  transform: translateY(-1px);
}

.skill-network-legend .legend-swatch {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  box-shadow: 0 0 6px currentColor;
}

/* Compact fallback list */
.skills-fallback {
  margin-top: var(--space-lg);
  border: 1px solid rgba(148, 163, 184, 0.12);
  border-radius: var(--radius-md);
  padding: var(--space-sm) var(--space-md);
  background: rgba(15, 23, 42, 0.25);
}

.skills-fallback > summary {
  cursor: pointer;
  color: rgba(148, 163, 184, 0.85);
  font-size: 0.82rem;
  font-weight: 500;
  padding: var(--space-xs) 0;
  list-style: none;
  transition: color 0.2s ease;
}

.skills-fallback > summary::-webkit-details-marker { display: none; }

.skills-fallback > summary::before {
  content: '▸ ';
  display: inline-block;
  transition: transform 0.2s ease;
}

.skills-fallback[open] > summary::before {
  content: '▾ ';
}

.skills-fallback > summary:hover {
  color: #f1f5f9;
}

.skills-fallback[open] .skills-grid {
  margin-top: var(--space-md);
}

/* Project card highlight states (driven by skill-network clicks) */
.project-card.skill-highlight {
  border-color: rgba(6, 182, 212, 0.55);
  box-shadow: 0 0 0 1px rgba(6, 182, 212, 0.35), 0 8px 32px rgba(6, 182, 212, 0.18);
  transform: translateY(-2px);
}

.project-card.skill-dim {
  opacity: 0.35;
  filter: saturate(0.5);
}

@media (max-width: 768px) {
  .skill-network-wrapper {
    height: 580px;
  }

  .skill-network-svg .node.hub-node text {
    font-size: 11px;
  }

  .skill-network-svg .node.skill-node text {
    font-size: 9px;
  }

  .skill-network-legend {
    gap: 6px 10px;
    padding: 6px 10px;
  }

  .skill-network-legend .legend-item {
    font-size: 0.62rem;
  }
}