Migrate from Bootstrap 4.0.0 to Bootstrap 5.3.3

[Copilot]

Upgrades Bootstrap from 4.0.0 (2018) to 5.3.3, addressing deprecations and using modern CDN infrastructure.

Changes

Dependencies updated:

• Bootstrap: 4.0.0 → 5.3.3
• jQuery: 3.2.1 → 3.7.1
• Popper: standalone 1.12.9 → @popperjs/core 2.11.8

Breaking change handled:

• Replaced deprecated btn-default with btn-secondary in both HTML and CSS (light/dark mode variants)

Security improvements:

• Added SRI integrity hashes to all CDN resources
• Migrated from deprecated maxcdn.bootstrapcdn.com to cdn.jsdelivr.net

Implementation

- <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
+ <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" integrity="sha384-QWT..." crossorigin="anonymous">

- <a class="btn btn-default" id="mini">Download Mini</a>
+ <a class="btn btn-secondary" id="mini">Download Mini</a>

Grid system (container, row, col-*) and custom styles remain fully compatible. No JavaScript component changes required—site uses only Bootstrap's CSS framework.

Screenshot

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• api.cdnjs.com
  • Triggering command: curl -s REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Migrate current older bootstrap to the latest version, ensuring nothing breaks and using the latest features in Bootstrap instead of older ways.

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