Help with Problem

I have a site @ https://www.weedshopinc.com On that site i have some IE issues and believe it or not, some firefox2 issues. Let me start with IE issues:
In the boxes on the front page, you will see text like "News" and "Member Login". I have an image that creates the color behind that text in the boxes. Notice how the color (image) does not stretch to the right side of the box. It stops short in IE. In firefox2, that is not seen. Here is the CSS for those colors (images):

.box_header {
font-size:15px;
margin:0;
padding:4px;

Please don't say I should have multi line indented coding. My text editor allows deleting & copying a line very easily.

I have narrowed down my problem to the following;

/*1*/<style type="text/css"> .in { position: fixed; width: 100%; left:70%; top: 26%; } </style>
/*2*/<style type="text/css"> .sh { position: fixed; width: 100%; left: 40%; top: 26%; } </style>
 
/*3*/
 
/*4*/<div class="in"> <select name="inout" style="width: 10%; height: 5mm"; >
/*5*/<option value="">Select</option>
/*6*/<option  value="in">In</option>
/*7*/<option  value="out">Out</option>

My website developed by the Bootstrap4, but the page is confusing on IE, is there any way to solve this problem quickly?

https://succulentsaddiction.com/soil-mix/

I'm trying to put a different cursor on my Big Cartel site but have never done anything with CSS. I've been copying the CSS coding from various cursor websites and pasting it into the CSS on my Big Cartel site but none of them are working. Here are some examples of the codes that I'm putting in:

Hey guys, I wanna ask you how to make some div with hover with one will change sizes and after that some text will show up becouse
text is too big for div in basic size.
Thanks for some help.