.semantic-app {
  display: grid;
  grid-template-areas:
    "header header"
    "side center"
    "side code";
  grid-template-columns: 280px 1fr 320px;
  grid-template-rows: auto 1fr;
  gap: 20px;
  min-height: calc(100vh - 120px);
}

.semantic-main {
  display: contents;
}

.semantic-side {
  grid-area: side;
  height: fit-content;
  position: sticky;
  top: 20px;
}

.semantic-center {
  grid-area: center;
}

.semantic-code {
  grid-area: code;
  height: fit-content;
  position: sticky;
  top: 20px;
}

.semantic-viz {
  min-height: 350px;
}

.semantic-demo {
  background: var(--surface-solid);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-strong);
  overflow: hidden;
  min-height: 300px;
}

.semantic-demo > * {
  display: block;
}

.semantic-demo header {
  background: var(--accent);
  color: white;
  padding: 15px;
  text-align: center;
  font-weight: 600;
}

.semantic-demo nav {
  background: var(--info);
  color: var(--bg-page);
  padding: 10px;
  text-align: center;
}

.semantic-demo nav a {
  color: var(--bg-page);
  margin: 0 10px;
  text-decoration: none;
}

.semantic-demo main {
  padding: 20px;
}

.semantic-demo article {
  background: var(--surface);
  padding: 15px;
  margin: 10px 0;
  border-radius: var(--radius-sm);
  border-right: 4px solid var(--success);
}

.semantic-demo aside {
  background: var(--bg-page);
  padding: 15px;
  margin: 10px 0;
  border-radius: var(--radius-sm);
  font-style: italic;
}

.semantic-demo section {
  background: var(--surface);
  padding: 15px;
  margin: 10px 0;
  border-radius: var(--radius-sm);
  border-right: 4px solid var(--accent);
}

.semantic-demo footer {
  background: var(--surface-strong);
  color: var(--text);
  padding: 15px;
  text-align: center;
}

@media (max-width: 1024px) {
  .semantic-app {
    grid-template-areas:
      "header"
      "side"
      "center"
      "code";
    grid-template-columns: 1fr;
    grid-template-rows: auto auto auto auto;
  }
  
  .semantic-side,
  .semantic-center,
  .semantic-code {
    position: static;
  }
}