* {
  box-sizing: border-box;
  font-family: 'Segoe UI', Tahoma, sans-serif;
}

body {
  margin: 0;
  background: #fafafa;
  color: #222;
}

header {
  background: white;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  padding: 1em 2em;
  position: sticky;
  top: 0;
}

header h1 {
  margin: 0;
}

nav a {
  margin-right: 1em;
  text-decoration: none;
  color: #0077cc;
  font-weight: 600;
}

nav a:hover {
  text-decoration: underline;
}

main {
  max-width: 800px;
  margin: 2em auto;
  padding: 1em;
}

.intro, .post, .card {
  background: white;
  padding: 1.5em;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.05);
  margin-bottom: 1.5em;
}

footer {
  text-align: center;
  padding: 1em;
  color: #666;
}