:root {
  --color-bg:           #0a0a0a;
  --color-surface:      #111111;
  --color-surface-2:    #1a1a1a;
  --color-border:       rgba(255, 255, 255, 0.07);
  --color-accent:       #0ea5a9;
  --color-accent-dim:   rgba(14, 165, 169, 0.12);
  --color-accent-glow:  rgba(14, 165, 169, 0.25);
  --color-gold:         #fbbf24;
  --color-gold-dim:     rgba(251, 191, 36, 0.15);
  --color-text:         #e0e0e0;
  --color-text-muted:   #888;
  --color-text-faint:   #555;
  --color-white:        #fff;
  --color-green:        #22c55e;

  --font-sans:          'Inter', system-ui, -apple-system, sans-serif;

  --font-size-xs:       0.75rem;
  --font-size-sm:       0.875rem;
  --font-size-base:     1rem;
  --font-size-lg:       1.125rem;
  --font-size-xl:       1.25rem;
  --font-size-2xl:      1.5rem;
  --font-size-3xl:      1.875rem;
  --font-size-hero:     clamp(2.5rem, 6vw, 4.5rem);

  --space-1:   0.25rem;
  --space-2:   0.5rem;
  --space-3:   0.75rem;
  --space-4:   1rem;
  --space-6:   1.5rem;
  --space-8:   2rem;
  --space-12:  3rem;
  --space-16:  4rem;
  --space-24:  6rem;

  --container-max: 900px;
  --nav-height:    64px;

  --transition-fast: 150ms ease;
  --transition-base: 250ms cubic-bezier(0.22, 1, 0.36, 1);
  --transition-slow: 400ms cubic-bezier(0.22, 1, 0.36, 1);

  --radius-sm:   4px;
  --radius-md:   8px;
  --radius-lg:   12px;
  --radius-full: 9999px;

  --ease-out-expo: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a {
  color: inherit;
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

.container {
  width: min(var(--container-max), 100% - var(--space-8));
  margin-inline: auto;
}

main > section {
  padding-block: var(--space-24);
}

#skills,
#education,
#contact {
  background: var(--color-surface);
}

.section-title {
  font-size: var(--font-size-2xl);
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: var(--space-12);
  position: relative;
  padding-bottom: var(--space-4);
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 36px;
  height: 2px;
  background: var(--color-accent);
  border-radius: var(--radius-full);
}

.section-intro {
  color: var(--color-text-muted);
  font-size: var(--font-size-lg);
  max-width: 600px;
  margin-bottom: var(--space-12);
  margin-top: calc(-1 * var(--space-8));
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.625rem var(--space-6);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: var(--font-size-sm);
  font-weight: 500;
  letter-spacing: 0.02em;
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: background var(--transition-fast),
              color var(--transition-fast),
              border-color var(--transition-fast),
              box-shadow var(--transition-fast);
}

.btn-primary {
  background: var(--color-accent);
  color: var(--color-bg);
}

.btn-primary:hover {
  background: #0c8d91;
  box-shadow: 0 0 20px var(--color-accent-glow);
}

.btn-ghost {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}

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

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

.btn-outline:hover {
  background: var(--color-accent-dim);
  box-shadow: 0 0 16px var(--color-accent-glow);
}

/* ------------------------------------------------------------------
   Navbar
   ------------------------------------------------------------------ */
#navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 900;
  height: var(--nav-height);
  background: transparent;
  transition: background var(--transition-base),
              backdrop-filter var(--transition-base),
              border-color var(--transition-base),
              box-shadow var(--transition-base);
  border-bottom: 1px solid transparent;
}

#navbar.scrolled {
  background: rgba(10, 10, 10, 0.82);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom-color: var(--color-border);
  box-shadow: 0 1px 0 var(--color-border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  padding-inline: var(--space-6);
  max-width: calc(var(--container-max) + var(--space-8) * 2);
  margin-inline: auto;
}

.nav-logo {
  font-weight: 700;
  font-size: var(--font-size-xl);
  background: linear-gradient(135deg, var(--color-accent), var(--color-gold));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.5px;
  flex-shrink: 0;
  transition: opacity var(--transition-fast);
}

.nav-logo:hover {
  opacity: 0.8;
}

.nav-links {
  display: flex;
  gap: var(--space-8);
}

.nav-links a {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  letter-spacing: 0.02em;
  transition: color var(--transition-fast);
  padding-block: var(--space-1);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--color-accent);
  transition: width var(--transition-base);
}

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

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

.nav-burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  flex-shrink: 0;
}

.nav-burger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition-base),
              opacity var(--transition-fast);
}

/* ------------------------------------------------------------------
   Social Links (hero)
   ------------------------------------------------------------------ */
.social-links {
  display: flex;
  gap: var(--space-4);
}

.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: var(--font-size-lg);
  transition: color var(--transition-fast),
              border-color var(--transition-fast),
              background var(--transition-fast),
              box-shadow var(--transition-fast);
}

.social-links a:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
  background: var(--color-accent-dim);
  box-shadow: 0 0 12px var(--color-accent-glow);
}

/* ------------------------------------------------------------------
   Hero
   ------------------------------------------------------------------ */
#hero {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding-top: calc(var(--nav-height) + var(--space-24));
  padding-bottom: var(--space-24);
  padding-inline: var(--space-8);
  max-width: calc(var(--container-max) + var(--space-8) * 2);
  margin-inline: auto;
  width: 100%;
  position: relative;
  overflow: hidden;
}

#hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 600px 400px at 10% 20%, rgba(14, 165, 169, 0.06) 0%, transparent 70%),
    radial-gradient(ellipse 500px 500px at 90% 80%, rgba(251, 191, 36, 0.05) 0%, transparent 70%);
  pointer-events: none;
}

#hero::after {
  content: '';
  position: absolute;
  inset: 0;
  opacity: 0.03;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 256px 256px;
  pointer-events: none;
}

.hero-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
  max-width: 680px;
  position: relative;
  z-index: 1;
}

.hero-eyebrow {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-accent);
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.hero-badge {
  display: inline-block;
  background: linear-gradient(135deg, var(--color-accent-dim), var(--color-gold-dim));
  color: var(--color-gold);
  border: 1px solid rgba(251, 191, 36, 0.25);
  padding: 2px 10px;
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  font-weight: 600;
  letter-spacing: 0.05em;
  box-shadow: 0 0 12px rgba(251, 191, 36, 0.1);
}

.hero-name {
  font-size: var(--font-size-hero);
  font-weight: 700;
  background: linear-gradient(135deg, var(--color-accent), var(--color-gold));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.08;
  letter-spacing: -2px;
}

.hero-tagline {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  max-width: 560px;
}

.hero-tagline li {
  color: var(--color-text-muted);
  font-size: var(--font-size-base);
  padding-left: var(--space-6);
  position: relative;
}

.hero-tagline li::before {
  content: '>';
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-weight: 600;
  font-family: monospace;
}

.hero-actions {
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
}

.hero-divider {
  width: 48px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-gold));
  border: none;
  margin: var(--space-16) 0;
  position: relative;
  z-index: 1;
  flex-shrink: 0;
}

.hero-about {
  position: relative;
  z-index: 1;
  width: 100%;
}

/* ------------------------------------------------------------------
   About
   ------------------------------------------------------------------ */
.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-12);
}

.about-photo {
  padding: 3px;
  background: linear-gradient(135deg, var(--color-accent), var(--color-gold));
  border-radius: 50%;
  width: fit-content;
}

.about-photo img {
  display: block;
  width: 134px;
  height: 134px;
  border-radius: 50%;
  object-fit: cover;
}

.about-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.about-content p {
  color: var(--color-text-muted);
}

.about-bullets {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.about-bullets li {
  color: var(--color-text-muted);
  padding-left: var(--space-6);
  position: relative;
  line-height: 1.6;
}

.about-bullets li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 10px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 6px rgba(14, 165, 169, 0.4);
}

.about-content a[href^="https"] {
  color: var(--color-accent);
  transition: opacity var(--transition-fast);
}

.about-content a[href^="https"]:hover {
  opacity: 0.8;
}

.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
  margin-top: var(--space-6);
  padding: var(--space-6);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
}

.stat-item {
  text-align: center;
}

.stat-value {
  display: block;
  font-size: var(--font-size-2xl);
  font-weight: 700;
  background: linear-gradient(135deg, var(--color-accent), var(--color-gold));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}

.stat-label {
  display: block;
  font-size: var(--font-size-xs);
  color: var(--color-text-faint);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: var(--space-1);
}

.about-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4) var(--space-6);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  margin-top: var(--space-2);
}

.about-meta i {
  color: var(--color-accent);
  margin-right: var(--space-1);
}

.about-meta a {
  color: var(--color-text-muted);
  transition: color var(--transition-fast);
}

.about-meta a:hover {
  color: var(--color-accent);
}

/* ------------------------------------------------------------------
   Experience Timeline
   ------------------------------------------------------------------ */
.timeline {
  position: relative;
  padding-left: var(--space-8);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(to bottom, var(--color-accent), var(--color-gold), transparent);
}

.timeline-item {
  position: relative;
  padding-bottom: var(--space-12);
}

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

.timeline-marker {
  position: absolute;
  left: calc(-1 * var(--space-8) - 4px);
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--color-accent);
  border: 2px solid var(--color-bg);
  box-shadow: 0 0 0 1px var(--color-accent), 0 0 8px rgba(14, 165, 169, 0.3);
}

.timeline-item:first-child .timeline-marker {
  background: var(--color-gold);
  box-shadow: 0 0 0 1px var(--color-gold), 0 0 12px rgba(251, 191, 36, 0.3);
}

.timeline-body {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: border-color var(--transition-base),
              box-shadow var(--transition-base);
}

.timeline-body:hover {
  border-color: rgba(14, 165, 169, 0.3);
  box-shadow: 0 0 20px rgba(14, 165, 169, 0.06);
}

.timeline-header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-1) var(--space-3);
  margin-bottom: var(--space-4);
}

.timeline-company {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-white);
  line-height: 1.3;
}

.timeline-company a {
  transition: color var(--transition-fast);
}

.timeline-company a:hover {
  color: var(--color-accent);
}

.timeline-role {
  font-size: var(--font-size-base);
  color: var(--color-accent);
  font-weight: 500;
}

.timeline-role::before {
  content: '·';
  margin-right: var(--space-3);
  color: var(--color-text-faint);
}

.timeline-badge {
  display: inline-block;
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-bg);
  background: var(--color-gold);
  padding: 1px 8px;
  border-radius: var(--radius-full);
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.timeline-period {
  font-size: var(--font-size-sm);
  color: var(--color-text-faint);
  margin-left: auto;
}

.timeline-bullets {
  padding: 0;
}

.timeline-bullets li {
  position: relative;
  padding-left: var(--space-6);
  color: var(--color-text-muted);
  font-size: var(--font-size-base);
  margin-bottom: var(--space-2);
  line-height: 1.6;
}

.timeline-bullets li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--color-text-faint);
}

.timeline-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-border);
}

.timeline-tags li {
  background: rgba(14, 165, 169, 0.08);
  color: var(--color-accent);
  border: 1px solid rgba(14, 165, 169, 0.15);
  border-radius: var(--radius-full);
  padding: 1px 10px;
  font-size: var(--font-size-xs);
  font-weight: 500;
}

/* ------------------------------------------------------------------
   Skills
   ------------------------------------------------------------------ */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-8);
}

.skill-category-name {
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-text-faint);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.skill-bar {
  display: block;
  width: 100%;
  height: 3px;
  background: var(--color-surface-2);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.skill-bar-fill {
  display: block;
  height: 100%;
  border-radius: var(--radius-full);
  background: linear-gradient(90deg, var(--color-accent), var(--color-gold));
  transition: width 0.8s var(--ease-out-expo);
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.skill-tags li {
  background: var(--color-surface-2);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  padding: var(--space-1) var(--space-4);
  font-size: var(--font-size-sm);
  transition: border-color var(--transition-fast),
              color var(--transition-fast),
              box-shadow var(--transition-fast);
  cursor: default;
}

.skill-tags li:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  box-shadow: 0 0 10px rgba(14, 165, 169, 0.1);
}

/* ------------------------------------------------------------------
   Education
   ------------------------------------------------------------------ */
.edu-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-6);
}

.edu-card {
  display: flex;
  gap: var(--space-6);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: border-color var(--transition-base),
              box-shadow var(--transition-base);
}

.edu-card:hover {
  border-color: rgba(14, 165, 169, 0.3);
  box-shadow: 0 0 20px rgba(14, 165, 169, 0.06);
}

.edu-icon {
  font-size: var(--font-size-2xl);
  color: var(--color-accent);
  flex-shrink: 0;
  padding-top: 2px;
}

.edu-card h3 {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: var(--space-1);
  line-height: 1.4;
}

.edu-institution {
  color: var(--color-accent);
  font-size: var(--font-size-sm);
  font-weight: 500;
}

.edu-sub {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  margin-top: var(--space-1);
}

.edu-period {
  display: block;
  font-size: var(--font-size-xs);
  color: var(--color-text-faint);
  margin-top: var(--space-2);
}

/* ------------------------------------------------------------------
   Projects
   ------------------------------------------------------------------ */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: var(--space-6);
}

.project-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  transition: border-color var(--transition-base),
              transform var(--transition-base),
              box-shadow var(--transition-base);
}

.project-card:hover {
  border-color: rgba(14, 165, 169, 0.3);
  transform: translateY(-3px);
  box-shadow: 0 8px 30px rgba(14, 165, 169, 0.08);
}

.project-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.project-card-header img {
  width: 36px;
  height: 36px;
  object-fit: contain;
}

.project-tag {
  font-size: var(--font-size-xs);
  color: var(--color-accent);
  background: var(--color-accent-dim);
  padding: 2px var(--space-3);
  border-radius: var(--radius-full);
  font-weight: 500;
  white-space: nowrap;
}

.project-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-white);
  line-height: 1.3;
}

.project-desc {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  line-height: 1.65;
  flex: 1;
}

.project-links {
  margin-top: auto;
  padding-top: var(--space-2);
}

.project-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  transition: color var(--transition-fast);
}

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

/* ------------------------------------------------------------------
   Contact
   ------------------------------------------------------------------ */
.section-intro {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
}

.availability-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-sm);
  color: var(--color-green);
  background: rgba(34, 197, 94, 0.08);
  border: 1px solid rgba(34, 197, 94, 0.2);
  padding: 2px 12px;
  border-radius: var(--radius-full);
  font-weight: 500;
}

.availability-dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--color-green);
  animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.contact-item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-4) var(--space-6);
  color: var(--color-text-muted);
  font-size: var(--font-size-base);
  transition: color var(--transition-fast),
              border-color var(--transition-fast),
              background var(--transition-fast),
              box-shadow var(--transition-fast);
}

.contact-item i {
  font-size: var(--font-size-xl);
  color: var(--color-accent);
}

.contact-item:hover {
  color: var(--color-white);
  border-color: rgba(14, 165, 169, 0.3);
  background: var(--color-accent-dim);
  box-shadow: 0 0 16px rgba(14, 165, 169, 0.08);
}

/* ------------------------------------------------------------------
   Footer
   ------------------------------------------------------------------ */
#site-footer {
  padding-block: var(--space-12);
  border-top: 1px solid var(--color-border);
  text-align: center;
}

.footer-social {
  display: flex;
  justify-content: center;
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}

.footer-social a {
  color: var(--color-text-faint);
  font-size: var(--font-size-xl);
  transition: color var(--transition-fast);
}

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

.footer-copy {
  color: var(--color-text-faint);
  font-size: var(--font-size-sm);
}

/* ------------------------------------------------------------------
   Entry Animations
   ------------------------------------------------------------------ */
.timeline-item,
.project-card,
.skill-category,
.edu-card,
.contact-item {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s var(--ease-out-expo),
              transform 0.5s var(--ease-out-expo);
}

.timeline-item.is-visible,
.project-card.is-visible,
.skill-category.is-visible,
.edu-card.is-visible,
.contact-item.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.timeline-item.is-visible:nth-child(1) { transition-delay: 0ms; }
.timeline-item.is-visible:nth-child(2) { transition-delay: 60ms; }
.timeline-item.is-visible:nth-child(3) { transition-delay: 120ms; }
.timeline-item.is-visible:nth-child(4) { transition-delay: 180ms; }
.timeline-item.is-visible:nth-child(5) { transition-delay: 240ms; }

.project-card.is-visible:nth-child(1) { transition-delay: 0ms; }
.project-card.is-visible:nth-child(2) { transition-delay: 60ms; }
.project-card.is-visible:nth-child(3) { transition-delay: 120ms; }
.project-card.is-visible:nth-child(4) { transition-delay: 180ms; }
.project-card.is-visible:nth-child(5) { transition-delay: 240ms; }
.project-card.is-visible:nth-child(6) { transition-delay: 300ms; }
.project-card.is-visible:nth-child(7) { transition-delay: 360ms; }

.skill-category.is-visible:nth-child(1) { transition-delay: 0ms; }
.skill-category.is-visible:nth-child(2) { transition-delay: 60ms; }
.skill-category.is-visible:nth-child(3) { transition-delay: 120ms; }
.skill-category.is-visible:nth-child(4) { transition-delay: 180ms; }
.skill-category.is-visible:nth-child(5) { transition-delay: 240ms; }

.edu-card.is-visible:nth-child(1) { transition-delay: 0ms; }
.edu-card.is-visible:nth-child(2) { transition-delay: 80ms; }
.edu-card.is-visible:nth-child(3) { transition-delay: 160ms; }

.contact-item.is-visible:nth-child(1) { transition-delay: 0ms; }
.contact-item.is-visible:nth-child(2) { transition-delay: 60ms; }
.contact-item.is-visible:nth-child(3) { transition-delay: 120ms; }

@media (prefers-reduced-motion: reduce) {
  .timeline-item,
  .project-card,
  .skill-category,
  .edu-card,
  .contact-item {
    opacity: 1;
    transform: none;
    transition: none;
  }

  html {
    scroll-behavior: auto;
  }
}

/* ------------------------------------------------------------------
   Responsive
   ------------------------------------------------------------------ */

/* Mobile ( < 640px ) */
@media (max-width: 639px) {
  .nav-links {
    display: none;
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: rgba(17, 17, 17, 0.97);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: var(--space-8) var(--space-6);
    flex-direction: column;
    gap: var(--space-6);
    border-bottom: 1px solid var(--color-border);
    z-index: 899;
  }

  .nav-links.nav-open {
    display: flex;
  }

  .nav-links a {
    font-size: var(--font-size-base);
    color: var(--color-text);
  }

  .nav-burger {
    display: flex;
  }

  .hero-name {
    letter-spacing: -1px;
  }

  #hero {
    padding-inline: var(--space-6);
  }

  .timeline-period {
    margin-left: 0;
    width: 100%;
    margin-top: var(--space-1);
  }

  .stats-row {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-6);
  }

  .contact-links {
    flex-direction: column;
  }

  .contact-item {
    width: 100%;
  }

  .section-intro {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* Tablet ( >= 640px ) */
@media (min-width: 640px) {
  .about-grid {
    grid-template-columns: 140px 1fr;
    align-items: start;
  }

  .about-photo img {
    width: 134px;
    height: 134px;
  }

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

/* Desktop ( >= 900px ) */
@media (min-width: 900px) {
  .nav-links {
    display: flex;
  }

  .nav-burger {
    display: none;
  }

  .about-grid {
    grid-template-columns: 200px 1fr;
    gap: var(--space-16);
  }

  .about-photo img {
    width: 194px;
    height: 194px;
  }

  #hero {
    padding-inline: var(--space-4);
  }
}