/* CSS Variables */
:root {
  --bg-primary: #0b0f14;
  --bg-secondary: #111821;
  --bg-tertiary: #18202b;
  --surface: #1e2732;
  --surface-hover: #252f3c;

  --text-primary: #f0f4f8;
  --text-secondary: #a9b4c2;
  --text-muted: #738191;

  --accent: #38bdf8;
  --accent-hover: #7dd3fc;
  --accent-soft: rgba(56, 189, 248, 0.12);

  --border: rgba(148, 163, 184, 0.12);
  --shadow: rgba(0, 0, 0, 0.35);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2.5rem;
  --space-xl: 4rem;
  --space-2xl: 6rem;

  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  --header-height: 68px;
  --max-width: 1120px;

  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 1rem);
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition-fast), background-color var(--transition-fast), box-shadow var(--transition-fast);
}

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

:focus:not(:focus-visible) {
  outline: none;
}

/* Utilities */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: -3rem;
  left: var(--space-md);
  z-index: 1001;
  background: var(--accent);
  color: var(--bg-primary);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.skip-link:focus {
  top: var(--space-sm);
}

/* Header / Nav */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 1000;
  background: rgba(11, 15, 20, 0.82);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.navbar {
  height: var(--header-height);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.04em;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.35rem 0.65rem;
}

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

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  list-style: none;
}

.nav-link {
  display: inline-block;
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.4rem 0.6rem;
  border-radius: var(--radius-sm);
  position: relative;
}

.nav-link:hover,
.nav-link[aria-current="true"] {
  color: var(--text-primary);
}

.nav-link[aria-current="true"]::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0.6rem;
  right: 0.6rem;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
}

.nav-cta {
  background: var(--accent);
  color: var(--bg-primary);
  font-weight: 600;
  padding: 0.5rem 0.9rem;
}

.nav-cta:hover {
  background: var(--accent-hover);
  color: var(--bg-primary);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.nav-toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

@media (max-width: 860px) {
  .nav-toggle {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    inset: var(--header-height) 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: rgba(11, 15, 20, 0.97);
    border-bottom: 1px solid var(--border);
    padding: var(--space-sm) var(--space-md);
    transform: translateY(-120%);
    opacity: 0;
    pointer-events: none;
    transition: transform var(--transition-base), opacity var(--transition-base);
  }

  .nav-menu.is-open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-link {
    display: block;
    padding: 0.75rem 0;
  }

  .nav-link[aria-current="true"]::after {
    left: 0;
    right: auto;
    width: 32px;
    bottom: 0.5rem;
  }

  .nav-cta {
    margin-top: var(--space-xs);
    text-align: center;
  }
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.7rem 1.25rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform var(--transition-fast), background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
}

.btn:hover {
  transform: translateY(-1px);
}

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

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

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

.btn-secondary:hover {
  background: var(--surface);
  border-color: var(--accent);
  color: var(--accent);
}

/* Hero */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--header-height);
  overflow: hidden;
}

.hero-visual {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.45;
}

.network-grid {
  position: absolute;
  inset: -10%;
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 60px 60px;
  transform: perspective(1000px) rotateX(55deg);
  transform-origin: center top;
  animation: grid-drift 24s linear infinite;
}

@keyframes grid-drift {
  0% { background-position: 0 0; }
  100% { background-position: 0 60px; }
}

.network-nodes span {
  position: absolute;
  width: 6px;
  height: 6px;
  background: var(--accent);
  border-radius: 50%;
  box-shadow: 0 0 18px var(--accent);
  animation: node-pulse 4s ease-in-out infinite;
}

.network-nodes span:nth-child(1) { top: 20%; left: 18%; animation-delay: 0s; }
.network-nodes span:nth-child(2) { top: 35%; left: 75%; animation-delay: 0.6s; }
.network-nodes span:nth-child(3) { top: 65%; left: 25%; animation-delay: 1.2s; }
.network-nodes span:nth-child(4) { top: 28%; left: 55%; animation-delay: 1.8s; }
.network-nodes span:nth-child(5) { top: 72%; left: 68%; animation-delay: 2.4s; }
.network-nodes span:nth-child(6) { top: 48%; left: 40%; animation-delay: 3s; }
.network-nodes span:nth-child(7) { top: 15%; left: 88%; animation-delay: 0.3s; }
.network-nodes span:nth-child(8) { top: 82%; left: 45%; animation-delay: 0.9s; }
.network-nodes span:nth-child(9) { top: 55%; left: 12%; animation-delay: 1.5s; }
.network-nodes span:nth-child(10) { top: 38%; left: 92%; animation-delay: 2.1s; }

@keyframes node-pulse {
  0%, 100% { opacity: 0.25; transform: scale(1); }
  50% { opacity: 0.8; transform: scale(1.6); }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.hero-kicker {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-sm);
}

.hero-title {
  font-size: clamp(2.8rem, 8vw, 4.8rem);
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: -0.04em;
  margin-bottom: var(--space-sm);
}

.hero-headline {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  color: var(--text-primary);
  font-weight: 600;
  margin-bottom: var(--space-xs);
}

.hero-subhead {
  font-size: 1.05rem;
  color: var(--accent);
  font-weight: 500;
  margin-bottom: var(--space-md);
}

.hero-intro {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 640px;
  margin-bottom: var(--space-lg);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.hero-socials {
  display: flex;
  gap: var(--space-sm);
}

.social-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  color: var(--text-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
}

.social-link:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-soft);
}

/* Sections */
.section {
  padding: var(--space-2xl) 0;
}

.section-kicker {
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--space-xs);
}

.section-title {
  font-size: clamp(1.6rem, 4vw, 2.25rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.section-header {
  margin-bottom: var(--space-xl);
  max-width: 680px;
}

/* About */
.about-content {
  max-width: 760px;
}

.about-content p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: var(--space-md);
}

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

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-md);
}

.skill-card {
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-md);
}

.skill-heading {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: var(--space-md);
  color: var(--text-primary);
}

.skill-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
}

.skill-list li {
  background: var(--surface);
  color: var(--text-secondary);
  font-size: 0.9rem;
  padding: 0.35rem 0.7rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

/* Featured work */
.project-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.project-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: clamp(1.25rem, 4vw, 2rem);
  box-shadow: 0 4px 24px var(--shadow);
}

.project-meta {
  margin-bottom: var(--space-sm);
}

.project-label {
  display: inline-block;
  color: var(--accent);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.25rem 0.5rem;
  background: var(--accent-soft);
  border: 1px solid rgba(56, 189, 248, 0.2);
  border-radius: var(--radius-sm);
}

.project-title {
  font-size: clamp(1.2rem, 3vw, 1.5rem);
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.project-description {
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
}

.project-details {
  list-style: disc;
  padding-left: 1.2rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
}

.project-details li {
  margin-bottom: 0.35rem;
}

.project-caption {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: var(--space-md);
}

.tech-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  list-style: none;
}

.tech-list li {
  font-size: 0.85rem;
  color: var(--text-secondary);
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius-sm);
}

/* GitHub */
.github {
  background: var(--bg-tertiary);
}

.github-controls {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.control-group {
  flex: 1 1 200px;
}

.repo-search,
.repo-sort,
.repo-language {
  width: 100%;
  padding: 0.65rem 0.85rem;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  font-size: 0.95rem;
}

.repo-search:focus,
.repo-sort:focus,
.repo-language:focus {
  border-color: var(--accent);
  outline: none;
  box-shadow: 0 0 0 2px var(--accent-soft);
}

.repo-status {
  text-align: center;
  padding: var(--space-xl) 0;
  color: var(--text-secondary);
}

.repo-loading,
.repo-error,
.repo-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
}

.spinner {
  width: 36px;
  height: 36px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.repo-error {
  color: #fca5a5;
  background: rgba(220, 38, 38, 0.1);
  border: 1px solid rgba(220, 38, 38, 0.25);
  border-radius: var(--radius-md);
  padding: var(--space-md);
}

.repo-error p {
  max-width: 640px;
}

.repo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.repo-card {
  display: flex;
  flex-direction: column;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-md);
  box-shadow: 0 4px 18px var(--shadow);
  transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.repo-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: 0 8px 28px rgba(56, 189, 248, 0.08);
}

.repo-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

.repo-name {
  font-size: 1.1rem;
  font-weight: 600;
  word-break: break-word;
}

.repo-name a {
  color: var(--text-primary);
}

.repo-name a:hover {
  color: var(--accent);
}

.repo-private {
  font-size: 0.7rem;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.15rem 0.4rem;
}

.repo-desc {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: var(--space-md);
  flex: 1 1 auto;
}

.repo-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-bottom: var(--space-sm);
}

.repo-meta span {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.repo-language-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
}

.repo-topics {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: var(--space-sm);
}

.repo-topic {
  font-size: 0.75rem;
  color: var(--text-muted);
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 0.2rem 0.45rem;
  border-radius: var(--radius-sm);
}

.repo-links {
  display: flex;
  gap: var(--space-sm);
  margin-top: auto;
}

.repo-links a {
  font-size: 0.9rem;
  font-weight: 500;
}

.github-profile {
  text-align: center;
}

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

.timeline {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  padding-left: 1.25rem;
}

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

.timeline-item {
  position: relative;
}

.timeline-marker {
  position: absolute;
  left: -1.25rem;
  top: 0.4rem;
  width: 12px;
  height: 12px;
  background: var(--accent);
  border: 2px solid var(--bg-secondary);
  border-radius: 50%;
  transform: translateX(-5px);
}

.card {
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-md);
}

.timeline-header {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-xs);
  margin-bottom: var(--space-sm);
}

.timeline-role {
  font-size: 1.15rem;
  font-weight: 600;
}

.timeline-org {
  color: var(--text-secondary);
  font-weight: 500;
}

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

.timeline-content p {
  color: var(--text-secondary);
}

/* Education */
.edu-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-md);
}

.edu-degree {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: var(--space-xs);
}

.edu-school {
  color: var(--text-secondary);
  font-weight: 500;
  margin-bottom: 0.15rem;
}

.edu-year {
  color: var(--text-muted);
  font-family: var(--font-mono);
  margin-bottom: var(--space-md);
}

.edu-highlights,
.cert-list {
  list-style: disc;
  padding-left: 1.2rem;
  color: var(--text-secondary);
}

.edu-highlights li,
.cert-list li {
  margin-bottom: 0.4rem;
}

.cert-heading {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: var(--space-md);
}

/* Contact */
.contact {
  background: linear-gradient(180deg, var(--bg-tertiary) 0%, var(--bg-primary) 100%);
}

.contact-content {
  max-width: 720px;
  margin: 0 auto;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.contact-content > * {
  width: 100%;
}

.contact-content .section-header {
  margin-left: auto;
  margin-right: auto;
}

.contact-content .section-title {
  margin-bottom: var(--space-md);
}

.contact-text {
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: var(--space-lg);
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

.contact-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.contact-links {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}

.contact-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-secondary);
  font-weight: 500;
}

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

.contact-note {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.contact-note code {
  color: var(--accent);
  font-family: var(--font-mono);
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: var(--space-lg) 0;
  background: var(--bg-primary);
}

.footer-content {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
}

.footer-name {
  font-weight: 700;
  color: var(--text-primary);
}

.footer-tagline {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer-links {
  display: flex;
  gap: var(--space-md);
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

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

.footer-copy {
  width: 100%;
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-top: var(--space-sm);
}

/* Reveal animations */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 600ms ease, transform 600ms ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
  }
}

/* Responsive typography */
@media (max-width: 640px) {
  :root {
    --space-2xl: 4rem;
  }

  .hero-intro {
    font-size: 1rem;
  }

  .timeline {
    padding-left: 0.9rem;
  }

  .timeline-marker {
    left: -0.9rem;
    transform: translateX(-4px);
  }

  .timeline-header {
    flex-direction: column;
    gap: 0.15rem;
  }

  .footer-content {
    flex-direction: column;
    text-align: center;
  }

  .footer-copy {
    margin-top: var(--space-sm);
  }
}

/* Print */
@media print {
  .site-header,
  .hero-visual,
  .nav-toggle,
  .github-controls,
  .contact-actions,
  .site-footer .footer-links,
  #github {
    display: none !important;
  }

  body {
    background: #fff;
    color: #000;
  }

  .section {
    padding: 1.5rem 0;
  }

  a {
    color: #000;
    text-decoration: underline;
  }

  .project-card,
  .skill-card,
  .card {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #ccc;
  }
}