Hi,
What do you mean by none of them worked ?
They have to work. If they don't, it means that you're not using the correct CSS code.
I had a deeper look at your website. For example, to make the main area + sidebar take the full width available, you can add such CSS code in media/templates/site/cassiopeia/css/user.css:
/* Expand the main content area to the left edge */
.site-grid .grid-child.container-component {
grid-column-start: full-start !important;
}
/* Expand the sidebar area to the right edge */
.site-grid .grid-child.container-sidebar-right {
grid-column-end: full-end !important;
}
Similarly, preventing the line return on add to cart buttons can be done by adding such CSS code as I was explaining :
.hikacart {
white-space: nowrap !important;
}
Both solutions do what they are supposed to do. I've tested them both on your website via my browser's developer tools.