:root {
  --bg: #0f172a;
  --card: #111827;
  --text: #f8fafc;
  --muted: #cbd5e1;
  --accent: #38bdf8;
  --light: #f8fafc;
  --dark-text: #0f172a;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: Arial, sans-serif;
  background: var(--light);
  color: var(--dark-text);
  line-height: 1.6;
}

.hero {
  min-height: 100vh;
  background: linear-gradient(135deg, #0f172a, #1e293b);
  color: var(--text);
  padding: 24px;
}

.nav {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--accent);
  color: #020617;
  display: grid;
  place-items: center;
  font-weight: 800;
}

.nav-links {
  display: flex;
  gap: 22px;
  list-style: none;
}

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

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

.menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 30px;
  cursor: pointer;
}

.hero-content {
  max-width: 900px;
  margin: 140px auto 0;
}

.tag {
  color: var(--accent);
  font-weight: 700;
  margin-bottom: 16px;
}

h1 {
  font-size: clamp(42px, 7vw, 76px);
  line-height: 1.05;
  margin-bottom: 24px;
}

.subtitle {
  max-width: 720px;
  color: var(--muted);
  font-size: 20px;
  margin-bottom: 34px;
}

.btn {
  display: inline-block;
  padding: 13px 22px;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 700;
  margin-right: 12px;
}

.primary {
  background: var(--accent);
  color: #020617;
}

.secondary {
  border: 1px solid var(--accent);
  color: var(--text);
}

.section {
  max-width: 1100px;
  margin: 0 auto;
  padding: 80px 24px;
}

.section h2 {
  font-size: 36px;
  margin-bottom: 24px;
}

.section p {
  font-size: 18px;
  margin-bottom: 16px;
}

.section-intro {
  color: var(--muted);
  max-width: 800px;
}

.dark {
  max-width: none;
  background: #0f172a;
  color: var(--text);
}

.dark > * {
  max-width: 1100px;
  margin-left: auto;
  margin-right: auto;
}

.timeline { display: grid; gap: 20px; }

.card,
.certificate-card {
  background: #111827;
  border: 1px solid #334155;
  border-radius: 18px;
  padding: 24px;
}

.card h3,
.certificate-card h3 {
  margin: 8px 0 12px;
  color: var(--accent);
}

.date,
.issuer {
  color: var(--muted);
  font-weight: 700;
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}

.skills-grid div {
  background: #e2e8f0;
  padding: 16px;
  border-radius: 14px;
  font-weight: 700;
}

.certificates-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-top: 26px;
}

.certificate-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 230px;
}

.cert-btn {
  display: inline-block;
  align-self: flex-start;
  background: var(--accent);
  color: #020617;
  padding: 11px 18px;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 800;
  margin-top: 18px;
}

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

.contact a {
  color: #0369a1;
  font-weight: 700;
}

footer {
  background: #020617;
  color: var(--muted);
  text-align: center;
  padding: 24px;
}

@media (max-width: 760px) {
  .menu-btn { display: block; }

  .nav-links {
    display: none;
    position: absolute;
    right: 24px;
    top: 82px;
    background: #111827;
    flex-direction: column;
    padding: 18px;
    border-radius: 14px;
    border: 1px solid #334155;
  }

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

  .hero-content { margin-top: 100px; }

  .skills-grid,
  .certificates-grid {
    grid-template-columns: 1fr;
  }

  .btn { margin-bottom: 12px; }
}