Typescript error with lighten and cssVar

[EnesAppsmen]

• polished version:
• JSS-in_CSS library and version:
• Any relevant JS library and version:

Mixin/Helper/Shorthand Usage

What You Are Seeing

What You Expected To See

No typescript error while using lighten and cssVar together

Reproduction

React 17.0.1
Typescript: 4.1.2
Polished: 4.1.1
Styled-components: 5.1.5;

[bhough]

@EnesAppsmen Similar to #550 this is a bug with our Flow > TS library. We will be moving to native TS in v5 and will address this then.