How to fix CSS formatting issue using ASP.NET web app?

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C#

CSS

HTML

Iam new to making a ASP.NET Core web application and i have most of it finished however I've come across a styling issue,where I cannot fit the size of some of the elements to the full width of the screen.Ive tried the css + html code separately to the ASP.NET and it works fine.Can anyone tell me where i am going wrong since the html/css works when i use it outside the ASP.NET web application in c#,but in the web application is squishes the elements in the center. Thanks in advance.

https://ibb.co/g7dx3gC Link to ASP.NET version
https://ibb.co/93JCvKB Picture of the Html/CSS of the ASP.NET
https://ibb.co/9rVDKvy Working one with no ASP.NET

What I have tried:

Ive tried looking and inspecting the website but cant find anything that will let me put my elements to fit the full width of the website.