Re: I fail to write the login form CSS
The login form is so low because you specified position bottom -200px and that means for it’s parent element.
If you wanted it 200px from the bottom of the header, that means either the header is not being closed properly or the header needs a position:relative;
or you could just change it to position from the top:
I am also concerned that it takes nearly half a minute for a page to completely load on your site.