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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica,
    Arial, sans-serif;
  color: #24292f;
  background: #ffffff;
  line-height: 1.6;
}

a {
  color: #0969da;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Header / Hero */
header {
  background: linear-gradient(135deg, #0d1117 0%, #161b22 100%);
  color: #f0f6fc;
}

nav {
  display: flex;
  gap: 1.5rem;
  padding: 1rem 2rem;
  justify-content: flex-end;
}

nav a {
  color: #c9d1d9;
  font-size: 0.95rem;
}

nav a:hover {
  color: #f0f6fc;
  text-decoration: none;
}

.hero {
  text-align: center;
  padding: 5rem 2rem 6rem;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.2rem;
  color: #8b949e;
  max-width: 540px;
  margin: 0 auto 2rem;
}

.btn {
  display: inline-block;
  background: #238636;
  color: #ffffff !important;
  padding: 0.65rem 1.5rem;
  border-radius: 6px;
  font-weight: 600;
  transition: background 0.2s;
}

.btn:hover {
  background: #2ea043;
  text-decoration: none;
}

/* Main sections */
main {
  max-width: 900px;
  margin: 0 auto;
  padding: 3rem 2rem;
}

section {
  margin-bottom: 4rem;
}

section h2 {
  font-size: 1.75rem;
  border-bottom: 1px solid #d0d7de;
  padding-bottom: 0.4rem;
  margin-bottom: 1.2rem;
}

/* Project cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.25rem;
}

.card {
  border: 1px solid #d0d7de;
  border-radius: 8px;
  padding: 1.25rem;
  transition: box-shadow 0.2s;
}

.card:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.card h3 {
  margin-bottom: 0.5rem;
}

.card p {
  color: #57606a;
  font-size: 0.9rem;
  margin-bottom: 0.75rem;
}

/* Footer */
footer {
  text-align: center;
  padding: 2rem;
  font-size: 0.85rem;
  color: #57606a;
  border-top: 1px solid #d0d7de;
}