<Container>
  <Row>
    <Col mb="m"><Box bg="black" color="white">auto</Box></Col>
    <Col width="contains"><Box bg="black" color="white">contains</Box></Col>
    <Col width={1} mb="m"><Box bg="black" color="white">full</Box></Col>
    <Col width={.5}><Box bg="black" color="white">half</Box></Col>
    <Col width={.5}><Box bg="black" color="white">half</Box></Col>
  </Row>
</Container>