Flexbox Layout

Create a simple page layout component with header and footer.

<div
  sx={{
    display: 'flex',
    flexDirection: 'column',
    // set this to `minHeight: '100vh'` for full viewport height
    minHeight: 256,
  }}>
  <header
    sx={{
      width: '100%',
    }}>
    Header
  </header>
  <main
    sx={{
      width: '100%',
      flex: '1 1 auto',
    }}>
    Main
  </main>
  <footer
    sx={{
      width: '100%',
    }}>
    Footer
  </footer>
</div>
<div
  sx={{
    display: 'flex',
    flexDirection: 'column',
    // set this to `minHeight: '100vh'` for full viewport height
    minHeight: 256,
  }}>
  <header
    sx={{
      width: '100%',
    }}>
    Header
  </header>
  <main
    sx={{
      width: '100%',
      flex: '1 1 auto',
    }}>
    Main
  </main>
  <footer
    sx={{
      width: '100%',
    }}>
    Footer
  </footer>
</div>

Flexbox styles are used to ensure the footer always renders at the bottom of the page, even when there isn't enough content to fill the viewport.

/** @jsx jsx */
import { jsx } from 'theme-ui'
export default props =>
  <div
    sx={{
      display: 'flex',
      flexDirection: 'column',
      minHeight: '100vh',
    }}>
    <header
      sx={{
        width: '100%',
      }}>
      Header
    </header>
    <main
      sx={{
        width: '100%',
        flex: '1 1 auto',
      }}>
      {props.children}
    </main>
    <footer
      sx={{
        width: '100%',
      }}>
      Footer
    </footer>
  </div>

Centered Containers

Centered, max-width containers can be added to the layout.

First, add a container size to your theme. This will be used for the max-width of the content.

// example theme
export default {
  sizes: {
    container: 768,
  }
}

Next create a Container component and use it within the layout.

/** @jsx jsx */
import { jsx } from 'theme-ui'
const Container = props =>
  <div
    {...props}
    sx={{
      maxWidth: 'container',
      mx: 'auto',
      px: 3,
    }}
  />
export default props =>
  <div
    sx={{
      display: 'flex',
      flexDirection: 'column',
      minHeight: '100vh',
    }}>
    <header
      sx={{
        width: '100%',
      }}>
      <Container>
        Header
      </Container>
    </header>
    <main
      sx={{
        width: '100%',
        flex: '1 1 auto',
      }}>
      <Container>
        {props.children}
      </Container>
    </main>
    <footer
      sx={{
        width: '100%',
      }}>
      <Container>
        Footer
      </Container>
    </footer>
  </div>

Make it Themeable

Add variant keys to the layout components to allow the styles to be customized in the theme object.

/** @jsx jsx */
import { jsx } from 'theme-ui'
const Container = props =>
  <div
    {...props}
    sx={{
      maxWidth: 'container',
      mx: 'auto',
      px: 3,
    }}
  />
export default props =>
  <div
    sx={{
      display: 'flex',
      flexDirection: 'column',
      minHeight: '100vh',
      variant: 'layout.root',
    }}>
    <header
      sx={{
        width: '100%',
        variant: 'layout.header',
      }}>
      <Container>
        Header
      </Container>
    </header>
    <main
      sx={{
        width: '100%',
        flex: '1 1 auto',
        variant: 'layout.main',
      }}>
      <Container>
        {props.children}
      </Container>
    </main>
    <footer
      sx={{
        width: '100%',
        variant: 'layout.footer',
      }}>
      <Container>
        Footer
      </Container>
    </footer>
  </div>

With the variant keys added above, you can adjust the layout styles at the theme level.

// example theme
export default {
  sizes: {
    container: 768,
  },
  layout: {
    header: {
      color: 'white',
      bg: 'black',
    },
    footer: {
      bg: 'gray',
    },
  },
}