# CMS Theme Development **URL:** \ **Category:** CMS Development\ **Tags:** css\ **Created:** [September 22, 2020, 10:59am UTC](https://community.hubspot.com/t/cms-theme-development/25757 "2020-09-22T10:59:17Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Venki](https://d10pqhm3lwygmk.cloudfront.net/user_avatar/community.hubspot.com/venki/32/87988_2.png) [@Venki](https://community.hubspot.com/u/Venki)\ **Post date:** [September 22, 2020, 10:59am UTC](https://community.hubspot.com/t/cms-theme-development/25757/1 "2020-09-22T10:59:17Z")
Can I use Bootstrap4 for the theme development. Mostly everyone are preferring CSS Flexible Box Layout. Let me know which is best, preferrable and which is commonly used for developing the responsive website for the theme. ---
**Author:** ![Anton](https://d10pqhm3lwygmk.cloudfront.net/user_avatar/community.hubspot.com/anton/32/103167_2.png) [@Anton](https://community.hubspot.com/u/Anton)\ **Post date:** [September 22, 2020, 1:54pm UTC](https://community.hubspot.com/t/cms-theme-development/25757/2 "2020-09-22T13:54:35Z")
Hi @Venki , of course you can. Are we talking about “dnd themes” or “old themes/templates”? Best way would be to download bootstrap, create a new file in the filemanager or designmanager(in the theme folder), open your main.css where all @imports are and “import” the it as last element. Or you can upload the bootstrap.css to your filemanager, open the Hub Settings and set the bootstrap.css in the website settings. (Don’t forget to do this in the blog too) best, Anton ---
**Author:** ![Venki](https://d10pqhm3lwygmk.cloudfront.net/user_avatar/community.hubspot.com/venki/32/87988_2.png) [@Venki](https://community.hubspot.com/u/Venki)\ **Post date:** [September 22, 2020, 2:05pm UTC](https://community.hubspot.com/t/cms-theme-development/25757/3 "2020-09-22T14:05:54Z")
Thanks Anton! I got it now!