How to create login form using css and html??

As I mentioned in your previous discussion on the same topic, you need more than HTML and CSS code to create a log-in form. 

https://community.adobe.com/t5/dreamweaver/how-to-create-a-login-and-registration-form-was-adobe-dreamweaver/m-p/11315392?page=1

It's a good idea to check your code often during development. There are tools in DW CC to help you with that.  Go to Window > Results > Validation.  Run the W3C validation tool and fix reported errors in your code.

The only thing I see going on in your code is that you have more <div> opening then you do  </div> closing which is why those lines are highlighted in red.  If you fix that it should solve the display issue.  There should be 2 closing div's on line 17 and that should do the trick.