Update Text Input styling to adhere to design specification

[aduth]

In implementing LG-8066, I noticed that text inputs and hints were not spaced correctly per the Figma Design System reference. The changes here eliminate all margins around the hint, and reduces the top margin of text fields from 0.5rem to 0.25rem.

Variant	Before	After
Default
With Hint

Live preview: https://federalist-2f194a10-945e-4413-be01-46ca6dae5358.sites.pages.cloud.gov/preview/18f/identity-style-guide/aduth-hint-spec/components/form-fields/

[aduth]

Visual regression failures are expecting since we're adjusting vertical spacing of form fields.

Example:

[nickttng]

LGTM. Do we want to apply the same to the dropdowns?

[aduth]

LGTM. Do we want to apply the same to the dropdowns?

Hm, yeah, these styles are applied in USWDS via the %block-input-styles Sass placeholder, which is (a) not directly customizable and (b) shared by many different types of inputs. If we want to effectively update the margin across the board, I can try to track down each place those styles are used and update them individually.

[nickttng]

Got it. If it's a light lift to update across the board, I think it'd be good to have spacing consistency between any label and input field.

[aduth]

the %block-input-styles Sass placeholder, which is (a) not directly customizable

Actually, I take that back. Apparently in Sass, if you define a placeholder which already exists, it doesn't necessarily "override" what existed previously, but it does output an additional set of styles which would effectively take precedence over the initial definition, which should give us the effect we want.

Example: https://www.sassmeister.com/gist/d12223c9afc58b44c411146e54053df4

[aduth]

Ok, the changes in 2871d86 should get us what we want. The updated preview should be available shortly.

[aduth]

I'm going to go ahead and merge this since I want to start implementing "Big" inputs, but let me know if you spot any issues @nickttng and I'll be happy to follow-up on them.

[nickttng]

Thank you, Andrew. I'll keep an eye out for the "Big" inputs.