:root {
  --primary-color: #2563eb;
  --primary-dark: #1d4ed8;
  --text-color: #111827;
  --text-muted: #6b7280;
  --bg-light: #f9fafb;
  --card-bg: #ffffff;
  --border-color: #e5e7eb;
}

body {
  font-family: 'Inter', system-ui, sans-serif;
}
/* ================================
   CSS Reset & Base
================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue",
    sans-serif;
  line-height: 1.6;
  background-color: #f9fafb;
  color: #111827;
  min-height: 100vh;
}

/* ================================
   Typography
================================ */
h1, h2, h3, h4, h5 {
  font-weight: 600;
  line-height: 1.25;
  color: #111827;
}

h1 {
  font-size: 2.25rem;
  margin-bottom: 1rem;
}

h2 {
  font-size: 1.75rem;
  margin-bottom: 0.75rem;
}

p {
  margin-bottom: 1rem;
  color: #374151;
}

a {
  color: #2563eb;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

section {
  margin-bottom: 4rem;
}

.section-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1rem;
}
.hero {
  text-align: center;
  padding: 4rem 1rem;
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 700;
}

.hero-subtitle {
  font-size: 1.2rem;
  color: var(--text-muted);
}

.skill-card, .project-card {
  background: var(--card-bg);
  padding: 1.8rem;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.06);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.skill-card:hover, .project-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.08);
}

.timeline-item {
  padding-left: 2.5rem;
  border-left: 3px solid var(--primary-color);
}

.timeline-dot {
  left: -8px;
  width: 14px;
  height: 14px;
}

.timeline-item {
  opacity: 0;
  animation: fadeIn 0.6s ease forwards;
}

@media (max-width: 600px) {
  h1 { font-size: 1.8rem; }
  h2 { font-size: 1.4rem; }
  .hero { padding: 2rem 1rem; }
  nav { gap: 1rem; font-size: 0.9rem; }
}

footer {
  text-align: center;
  padding: 2rem 0;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
  margin-top: 4rem;
}