refactor(v2): reduce top padding in doc content container

[lex111]

Motivation

Re-attempted to apply the changes from #4877.

Because of style minification the changes from that PR didn't apply (didn't notice it right away). So I decided to use the built-in Infima utility classes to achieve purpose of that PR.

Have you read the Contributing Guidelines on pull requests?

Yes

Test Plan

Preview.

Related PRs

(If this PR adds or changes functionality, please take some time to update the docs at https://github.com/facebook/docusaurus, and link to your PR here.)

[lex111]

Now top padding will be slightly larger instead of 0.5 -> 1rem, but it's still good.

[netlify]

✔️ [V2]

🔨 Explore the source changes: 04c4442

🔍 Inspect the deploy log: https://app.netlify.com/sites/docusaurus-2/deploys/60cb1fedd0a9040007650059

😎 Browse the preview: https://deploy-preview-4995--docusaurus-2.netlify.app

[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟠 Performance	64
🟢 Accessibility	97
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-4995--docusaurus-2.netlify.app/

[github-actions]

Size Change: -21 B (0%)

Total Size: 624 kB

ℹ️ View Unchanged

Filename	Size	Change
website/build/assets/css/styles.********.css	87.6 kB	-21 B (0%)
website/build/assets/js/main.********.js	445 kB	0 B
website/build/blog/2017/12/14/introducing-docusaurus/index.html	63.3 kB	0 B
website/build/docs/introduction/index.html	235 B	0 B
website/build/index.html	28.1 kB	0 B

_{compressed-size-action}

[slorber]

👍

[idontknowjs]

@slorber @lex111

I feel this max-width for smaller viewports added can be removed the DocPage here. This is causing the text in TOC to be wrapped to the next line and main content to shrink. I would like to submit the PR!

Removing this docItemWrapper class probably makes the layout look better as shown below!

[slorber]

thanks @CovalentBond , will fix this in #5035