For a large website with over a hundred TYPO3 pages, selective improvements in responsive behavior were implemented.
The website was based on a self-made template based on Fluid Styled Content. The template is created manually via TypoScript and template folders below fileadmin.
For the creation of the TYPO3 templates, the extension: mask was used.
No known framework was used, but customized HTML and CSS were created.
The changes thus included changes to the template files of mask and CSS optimizations.