布局预设 Layout

<div class="xxd-layout" data-cols="1-2">
  <div class="xxd-surface" data-level="sunken" style="padding:16px">侧栏 1</div>
  <div class="xxd-surface" style="padding:16px">主体 2</div>
</div>

export function LayoutDemo() {
  return (
    <Grid variant="2up" gap="base">
      <GridItem>
        <Surface className="rounded-lg p-4">侧栏 1</Surface>
      </GridItem>
      <GridItem>
        <Surface className="rounded-lg p-4">主体 2</Surface>
      </GridItem>
    </Grid>
  );
}