:root {
  --md-primary: #1E88E5;
  --md-on-primary: #FFFFFF;
  --md-surface: #FFFFFF;
  --md-background: #E3F2FD;
  --md-radius: 16px;
  --md-shadow: 0 4px 12px rgba(0,0,0,0.15);
  --md-padding: 20px;
  --md-gap: 16px;
  --footer-height: 64px;
}
body {
  font-family: 'Roboto', sans-serif;
  margin: 0;
  background-color: var(--md-background);
  color: #333;
}
header {
  background-color: var(--md-primary);
  color: var(--md-on-primary);
  padding: var(--md-padding);
  text-align: center;
}
header h1 { margin: 0; font-weight: 700; }
header h1 a { color: inherit; text-decoration: none; }
header p { margin-top: 8px; font-weight: 400; }
main {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--md-padding);
  min-height: calc(100vh - var(--footer-height) - var(--md-padding)*2);
}
.cards {
  display: flex;
  flex-wrap: wrap;
  gap: var(--md-gap);
  justify-content: center;
}
.card {
  background-color: var(--md-surface);
  border-radius: var(--md-radius);
  box-shadow: var(--md-shadow);
  padding: var(--md-padding);
  width: 300px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  display: flex;
  flex-direction: column;
  margin-bottom: 20px;
}
.card:hover { transform: translateY(-4px); box-shadow: 0 8px 24px rgba(0,0,0,0.2); }
.card h3 { margin-top: 0; color: var(--md-primary); font-weight: 500; }
.card a { display: inline-block; margin-top: 8px; color: var(--md-primary); text-decoration: none; font-weight: 500; }
.card a:hover { text-decoration: underline; }
footer {
  background-color: #0D47A1;
  color: white;
  text-align: center;
  padding: 16px;
  font-size: 0.9em;
}
.footer-author {
  color: inherit;
  text-decoration: none;
}
@media (max-width: 600px) { .card { width: 90%; } }
@media (min-width: 601px) and (max-width: 900px) { .card { width: 45%; } }