[12.x] Update CSS in minimal exception view.

[FoksVHox]

This improves the work made in #57318, as I was made aware of that I had forgotten to update the CSS, before it would work.

Accessibility and semantic improvements:

• Changed the error code container from a <div> to an <h1> element to provide semantic meaning and improve accessibility for screen readers. (src/Illuminate/Foundation/Exceptions/views/minimal.blade.php)
• Added role="main" to the main content container <div> to help assistive technologies identify the primary content region. (src/Illuminate/Foundation/Exceptions/views/minimal.blade.php)

[NickSdot]

Unrelated to what you changed. But it is actually insane that we dump a whole Tailwind in this layout to style a few words. We probably should make this a few lines of Vanilla CSS

[FoksVHox]

Unrelated to what you changed. But it is actually insane that we dump a whole Tailwind in this layout to style a few words. We probably should make this a few lines of Vanilla CSS

Actually, it doesn't include the whole tailwind css cdn, but only what's used.

[NickSdot]

Unrelated to what you changed. But it is actually insane that we dump a whole Tailwind in this layout to style a few words. We probably should make this a few lines of Vanilla CSS

Actually, it doesn't include the whole tailwind css cdn, but only what's used.

Plus normalising. You get the gist. How hard it is to review your changes, even though there are like 10 lines of markup, shows that something is off.