:root {
  --bg: #0d0f1a;
  --bg-alt: #14172b;
  --surface: rgba(255, 255, 255, 0.06);
  --text: #f5f6fa;
  --text-muted: #b7bdd4;
  --accent: #5ac4ff;
  --accent-strong: #00d1b2;
  --border: rgba(255, 255, 255, 0.12);
  --shadow: 0 18px 45px rgba(5, 13, 59, 0.35);
  --max-width: 1100px;
  --radius-lg: 24px;
  --radius-md: 16px;
  --radius-sm: 10px;
  scroll-behavior: smooth;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  background: radial-gradient(circle at top left, #212754, #090b17 45%);
  color: var(--text);
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

.skip-link {
  position: absolute;
  left: -999px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
}

.skip-link:focus {
  position: static;
  width: auto;
  height: auto;
  padding: 0.75rem 1rem;
  background: var(--accent);
  color: #001127;
  border-radius: var(--radius-sm);
  z-index: 99;
}

.site-header {
  position: relative;
  padding: 1.5rem 1.75rem 0;
  background: linear-gradient(135deg, rgba(90, 196, 255, 0.14), rgba(0, 209, 178, 0.08));
  overflow: hidden;
}

.site-header::after {
  content: '';
  position: absolute;
  inset: 0;
  background: url('data:image/svg+xml,%3Csvg width="300" height="300" viewBox="0 0 300 300" xmlns="http://www.w3.org/2000/svg"%3E%3Cdefs%3E%3ClinearGradient id="grad" x1="0%25" y1="0%25" x2="100%25" y2="100%25"%3E%3Cstop offset="0%25" stop-color="%235AC4FF" stop-opacity="0.16"/%3E%3Cstop offset="100%25" stop-color="%2300D1B2" stop-opacity="0.02"/%3E%3C/linearGradient%3E%3C/defs%3E%3Cpath d="M150 280C230 280 280 230 280 150C280 70 230 20 150 20C70 20 20 70 20 150C20 230 70 280 150 280Z" fill="url(%23grad)"/%3E%3C/svg%3E')
    no-repeat center / cover;
  opacity: 0.7;
  pointer-events: none;
}

.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  position: relative;
  z-index: 2;
}

.logo {
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--text);
}

.menu-toggle {
  background: none;
  border: 1px solid transparent;
  border-radius: 12px;
  padding: 0.5rem;
  display: none;
  flex-direction: column;
  gap: 0.35rem;
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  width: 1.5rem;
  height: 2px;
  background: var(--text);
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.menu-toggle:focus-visible {
  outline: 2px solid var(--accent);
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 1.5rem;
  padding: 0;
  margin: 0;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  letter-spacing: 0.02em;
  padding: 0.5rem 0;
  position: relative;
  transition: color 0.2s ease;
}

.nav-links a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(120deg, var(--accent), var(--accent-strong));
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.25s ease;
}

.nav-links a:focus-visible,
.nav-links a:hover {
  color: var(--text);
}

.nav-links a:hover::after,
.nav-links a:focus-visible::after {
  transform: scaleX(1);
  transform-origin: left;
}

.hero {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 3rem;
  align-items: center;
  max-width: var(--max-width);
  margin: 4rem auto 5rem;
  position: relative;
  z-index: 1;
}

.hero__content h1 {
  font-size: clamp(2.5rem, 6vw, 3.5rem);
  margin-bottom: 1rem;
}

.hero__content p {
  color: var(--text-muted);
  line-height: 1.7;
  font-size: 1.05rem;
}

.hero__contact {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  margin-top: 1.75rem;
  font-weight: 500;
}

.hero__contact a {
  color: var(--text);
  text-decoration: none;
}

.hero__contact a:hover,
.hero__contact a:focus-visible {
  color: var(--accent);
}

.hero__actions {
  margin-top: 2rem;
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.btn {
  padding: 0.85rem 1.75rem;
  border-radius: 999px;
  font-weight: 600;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.btn--primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  color: #041225;
  box-shadow: var(--shadow);
}

.btn--primary:hover,
.btn--primary:focus-visible {
  transform: translateY(-2px);
}

.btn--ghost {
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: var(--text);
}

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

.hero__stats {
  display: grid;
  gap: 1rem;
}

.hero__stats article {
  padding: 1.5rem;
  background: var(--surface);
  border: 1px solid rgba(90, 196, 255, 0.15);
  border-radius: var(--radius-md);
  backdrop-filter: blur(10px);
  box-shadow: 0 20px 35px rgba(9, 14, 42, 0.2);
}

.hero__stats h2 {
  margin: 0;
  font-size: 2rem;
}

main {
  flex: 1;
}

.section {
  padding: 5rem 1.5rem;
}

.section--alt {
  background: rgba(12, 16, 36, 0.78);
}

.section__heading {
  max-width: var(--max-width);
  margin: 0 auto 2.5rem;
}

.section__heading h2 {
  font-size: clamp(2rem, 4.5vw, 2.75rem);
  margin-bottom: 0.75rem;
}

.eyebrow {
  font-size: 0.85rem;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
}

.two-column {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
  color: var(--text-muted);
  line-height: 1.8;
}

.skills-grid {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
}

.skill {
  background: var(--surface);
  padding: 1.5rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  min-height: 160px;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.skill h3 {
  margin: 0;
  color: var(--text);
}

.skill p {
  margin: 0;
  color: var(--text-muted);
  line-height: 1.6;
}

.filters {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 0.5rem;
}

.filter-btn {
  border: 1px solid rgba(90, 196, 255, 0.3);
  background: transparent;
  color: var(--text-muted);
  border-radius: 999px;
  padding: 0.6rem 1.4rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border 0.2s ease;
}

.filter-btn.is-active,
.filter-btn:hover,
.filter-btn:focus-visible {
  background: var(--accent);
  color: #001127;
  border-color: transparent;
}

.projects-grid {
  max-width: var(--max-width);
  margin: 3rem auto 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.75rem;
}

.empty-state {
  grid-column: 1 / -1;
  padding: 2.5rem;
  text-align: center;
  background: rgba(12, 16, 36, 0.85);
  border-radius: var(--radius-md);
  border: 1px dashed rgba(90, 196, 255, 0.35);
  color: var(--text-muted);
}

.project-card {
  background: rgba(12, 16, 36, 0.8);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-lg);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  position: relative;
  overflow: hidden;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.project-card::before {
  content: attr(data-category);
  position: absolute;
  top: 1.5rem;
  right: -3rem;
  font-size: 0.85rem;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.15);
  transform: rotate(35deg);
}

.project-card:hover,
.project-card:focus-within {
  transform: translateY(-4px);
  box-shadow: 0 20px 40px rgba(8, 13, 37, 0.45);
}

.project-card h3 {
  margin: 0;
  font-size: 1.4rem;
}

.project-card p {
  margin: 0;
  color: var(--text-muted);
  line-height: 1.7;
}

.project-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: -0.25rem;
}

.tag {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  padding: 0.35rem 0.85rem;
  background: rgba(90, 196, 255, 0.15);
  color: var(--accent);
  font-size: 0.85rem;
  letter-spacing: 0.03em;
}

.project-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.project-links a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.project-links a:hover,
.project-links a:focus-visible {
  text-decoration: underline;
}

.timeline {
  list-style: none;
  margin: 0 auto;
  padding: 0;
  max-width: var(--max-width);
  position: relative;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 18px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, rgba(90, 196, 255, 0.6), rgba(0, 209, 178, 0.05));
}

.timeline li {
  position: relative;
  padding-left: 3.5rem;
  margin-bottom: 2.5rem;
}

.timeline__marker {
  position: absolute;
  left: 8px;
  top: 0.2rem;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 2px solid rgba(90, 196, 255, 0.4);
  background: var(--bg-alt);
}

.timeline__content {
  background: rgba(12, 16, 36, 0.9);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  border: 1px solid rgba(90, 196, 255, 0.12);
  box-shadow: 0 18px 30px rgba(5, 11, 38, 0.35);
}

.timeline__content h3 {
  margin-top: 0;
  margin-bottom: 0.35rem;
}

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

.timeline__content p {
  color: var(--text-muted);
  line-height: 1.7;
}

.education-card {
  max-width: calc(var(--max-width) - 200px);
  margin: 0 auto;
  background: rgba(8, 14, 32, 0.85);
  border-radius: var(--radius-lg);
  border: 1px solid rgba(90, 196, 255, 0.14);
  padding: 2rem 2.5rem;
  box-shadow: 0 20px 35px rgba(5, 11, 38, 0.35);
}

.education-card h3 {
  margin-bottom: 0.35rem;
}

.education-card span {
  display: block;
  color: var(--text-muted);
  font-weight: 500;
  margin-bottom: 1rem;
}

.education-card p {
  color: var(--text-muted);
  line-height: 1.7;
}

.contact-card {
  max-width: calc(var(--max-width) - 200px);
  background: rgba(12, 16, 36, 0.82);
  margin: 0 auto;
  padding: 2.5rem;
  border-radius: var(--radius-lg);
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 25px 40px rgba(9, 10, 32, 0.35);
  color: var(--text-muted);
  line-height: 1.8;
}

.contact-links {
  list-style: none;
  margin: 2rem 0 0;
  padding: 0;
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.contact-links a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}

.contact-links a:hover,
.contact-links a:focus-visible {
  text-decoration: underline;
}

.site-footer {
  text-align: center;
  padding: 3rem 1.5rem 4rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  background: rgba(6, 9, 22, 0.95);
}

.back-to-top {
  display: inline-block;
  margin-top: 0.75rem;
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}

.back-to-top:hover,
.back-to-top:focus-visible {
  text-decoration: underline;
}

@media (max-width: 960px) {
  .menu-toggle {
    display: flex;
  }

  .nav-links {
    position: absolute;
    right: 1.5rem;
    top: calc(100% + 0.75rem);
    background: rgba(12, 16, 36, 0.95);
    border-radius: var(--radius-md);
    border: 1px solid rgba(90, 196, 255, 0.2);
    padding: 1rem 1.25rem;
    flex-direction: column;
    gap: 0.5rem;
    width: min(220px, 80vw);
    box-shadow: 0 18px 30px rgba(8, 9, 28, 0.4);
    transform: scale(0.9);
    transform-origin: top right;
    opacity: 0;
    visibility: hidden;
    transition: transform 0.25s ease, opacity 0.25s ease;
  }

  .nav-links.is-open {
    transform: scale(1);
    opacity: 1;
    visibility: visible;
  }

  .timeline::before {
    left: 10px;
  }

  .timeline li {
    padding-left: 2.75rem;
  }

  .contact-card {
    max-width: var(--max-width);
  }
}

@media (max-width: 640px) {
  .hero {
    margin-top: 2.5rem;
  }

  .site-header {
    padding: 1rem 1.25rem 0;
  }

  .section {
    padding: 4rem 1.25rem;
  }

  .project-card {
    padding: 1.75rem;
  }
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}