[nailer]

I did.

    .compose-form .compose-form__modifiers .compose-form__upload-description input::placeholder { opacity: 1; } 

That looks like BEM, with all the underscores and modifiers.

Proper nested SASS would look like:

    .compose-form .upload-description input::placeholder { opacity: 1; } 

Scoped CSS would look like:

    .compose-form-abc123 .however-deep-or-shallow-you-want { opacity: 1; }