bad class names.

https://github.com/FACG6/posts-project/blob/543acb90ac266203e938b072a03ac282f6506b41/public/css/stulySignup.css#L6

don't use camelcase for class names.

There are many conventions. BEM is a popular one that goes like this
Block__Element--modifier

for example
```css
.signup-form

.signup-form__input

.signup-form__input--green 

or 

.signup-form__input--selected
```