host variable need highlight

[IIIlIIIIIII]

As shown in the figure, the host variable is not highlighted. Can the host variable be highlighted, for example, by using purple?

[IIIlIIIIIII]

It seems that the colors are not distinguished due to the conflict caused by the JetBarins Darcula Theme plugin I installed

[spburtsev]

Currently, host variables are highlighted using the function parameter color, so it fully depends on your color theme.
I am planning to add semantic highlighting to this extension, though.