No value no css

[zomem]

const Line = styled(div)`
  background-color: ${props => props.bgColor};
  margin-left: ${props => props.margin};
`

if bgColor='#fff' and margin=''，

{
    --b9s1f2v-1: #fff;
}

.b9s1f2v{
  background-color: var(--b9s1f2v-1);
}

Just like this, margin has no value, and the generated css has no margin-left. How to implement it.🤔