Combining Border-Top,Border-Right,Border-Left,Border-Bottom in CSS

Combining border-top,border-right,border-left,border-bottom in CSS

No, you cannot set them all in a single statement.

At the general case, you need at least three properties:

border-color: red green white blue;
border-style: solid dashed dotted solid;
border-width: 1px 2px 3px 4px;

However, that would be quite messy. It would be more readable and maintainable with four:

border-top:    1px solid  #ff0;
border-right:  2px dashed #f0F;
border-bottom: 3px dotted #f00;
border-left:   5px solid  #09f;

How to take all borders out of button except top border?

Reset border first(note that order is important):

border: none;
border-top: 2px solid red;

.button {  background-color: black;  border: none;  border-top: 2px solid red;  color: white;  padding: 15px 32px;  text-align: center;  text-decoration: none;  font-size: 16px;  outline: none;}

<a href="#" class="button">Button1</a><button class="button">Button2</button>

Why is the border-left border-right not working for Bootstrap 5 Django?

You need to use border-start or border-end instead of border-left or border-right in bootstrap 5.

Horizontal direction sensitive variables, utilities and mixins are renamed with more logical names — start and end in lieu of left and right in Bootstrap 5.

You can see more bootstrap 5 migration details here:
https://getbootstrap.com/docs/5.0/migration/#sass

Is it possible to move border-bottom left or right in a list?

You're applying this padding to your ul but not to the li elements. Firstly you need to reset the padding of the ul to 0 (as most browsers apply padding-left to the ul element by default):

.menuoptions {
    ...
    padding: 0;
}

Then give the padding-left to your li elements:

.menuoptions li {
    ...
    padding-left: 10px; 
}

Working JSFiddle demo.

Use HTML Div to add border only on top and bottom?

Just a case of:

<h3 style="background-color:red; padding:2% 0 2% 0; border-top:5px solid green; border-bottom: 5px solid green;">
This is a header
</h3>

Combining Border-Top,Border-Right,Border-Left,Border-Bottom in CSS