fix: ensure footer is pushed to the bottom on large screens

[sibaiper]

Summary

Fixes footer layout issue on very wide screens where the footer does not stick to the bottom of the page.

Problem

• On large screens, the homepage layout leaves the footer floating above the bottom of the viewport.
• This looks fine on normal screens, but on very wide screens the gap is obvious.

Screenshots:

• Big screen (before):

• Small/normal screen (before):

Changes Made

• Set html and body to take up the full screen height.
• Adjusted footer styling so it always sticks to the bottom.

Testing

• Verified locally on normal and wide screens.
• Layout works consistently across different viewport sizes.

---

Let me know if further adjustments are needed.

closes #2079

[netlify]

✅ Deploy Preview for expressjscom-preview ready!

Name	Link
🔨 Latest commit	60207f0
🔍 Latest deploy log	https://app.netlify.com/projects/expressjscom-preview/deploys/68fccf919e006a0008251760
😎 Deploy Preview	https://deploy-preview-2075--expressjscom-preview.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[github-actions]

🚦 Lighthouse Results (Mobile & Desktop)

URL	Device	Perf	A11y	Best Practices
/	mobile	🔴 59	🟢 100	🟢 96
/en/blog/posts.html	mobile	🟠 88	🟢 96	🟢 96
/en/5x/api.html	mobile	🔴 70	🟢 95	🟢 96
/	desktop	🟢 100	🟢 100	🟢 96
/en/blog/posts.html	desktop	🟢 99	🟢 96	🟢 92
/en/5x/api.html	desktop	🟢 98	🟢 95	🟢 96

[ShubhamOulkar]

LGTM