body {
  display: grid;
  grid-template-areas:
    "header header header"
    "nav main aside"
    "footer footer footer";
  grid-template-rows: auto 1fr auto;
  grid-template-columns: 200px 1fr 200px;
  min-height: 100vh;
  margin: 0;
  gap: 10px;
}

.header { grid-area: header; background-color: #f0f0f0; padding: 20px; text-align: center; }
.nav { grid-area: nav; background-color: #e0e0e0; padding: 15px; }
.main { grid-area: main; background-color: #ffffff; padding: 20px; }
.aside { grid-area: aside; background-color: #e0e0e0; padding: 15px; }
.footer { grid-area: footer; background-color: #333; color: white; padding: 20px; text-align: center; }

@media (max-width: 768px) {
  body {
    grid-template-areas:
      "header"
      "nav"
      "main"
      "aside"
      "footer";
    grid-template-rows: auto auto 1fr auto auto;
    grid-template-columns: 1fr;
  }
}