Question: Can we add custom color names to $color variables?

I am new to theming and trying to add some custom color names to mytheme but those don't get compiled. A

In the `_variables.scss` file, I updated the $colors variable to include a "custom" color [see below]
```sass
$colors: (
    "custom": #303748,
    "blue": #2196F3,
    ....
);
```
But when I try to use it in my react component like `text-custom` or `bg-custom-500` it doesn't work. 