When you use React with TypeScript, you have have seen an error like this.

Type '{ "--language-color": string; }' is not assignable to type 'Properties<string | number, string & {}>'. Object literal may only specify known properties, and '"--language-color"' does not exist in type 'Properties<string | number, string & >'. The expected type comes from property 'style' which is declared here on type 'DetailedHTMLProps<HTMLAttributes<HTMLElement>, HTMLElement>'

Cast it to React.CSSProperties.

1<i2  style={{ "--language-color": item.primaryLanguage.color } as React.CSSProperties}3  className={`w-4 h-4 rounded-full bg-[var(--language-color)]`}4/>