Twilight, Section 5: Adjust the border color for search input

[alaminfirdows]

Description
Closes #649

Adjust the border color on form elements in the search form block to make the inputs stand out against the white background. Previously, they were hard to see because the accent color was too similar to the background color.

Screenshots

Testing Instructions

1. Open the Appearance menu, then go to Editor > Styles.
2. Turn on the Twilight style variation.
3. Create a new page.
4. Add a Group Block to the page, then select Section Style 5 for it.
5. Inside this section, insert a Search Block.
6. Visit the page to see the section with the search block displayed.

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[juanfra]

Thank you! Works well. I believe the !important is not needed here.

[alaminfirdows]

Thanks @juanfra.

I've also noticed that there is some additional override code for the comment block. Shouldn't we consider removing it to avoid duplicating the code?

Ref: https://github.com/WordPress/twentytwentyfive/pull/650/files/a30575ef27ca892f079b2606a5120d2976d229d3#diff-60a85af5c000152e40c3680e65867153567c39f66b221f8200e757de4d123f5bR245

[juanfra]

I am not sure if I understand. The two overrides are needed to fix the bug with the comments block and the search block. Can you please elaborate on why we should remove it?

[alaminfirdows]

I wanted to point out that the comment block override has some additional changes that we don't really need. We should keep just the border color, but we can remove the other properties, such as border-radius, margin, and font-size.

What do you think about this?