CSS to change the right triangle to collapse outline

[meebee]

I’m trying to change the triangle icon that allows me to collapse and expand my outlines. I’ve tried various changes using CSS snippets, but nothing seems to work.

What I’m trying to do

Instead of having the > and v icons to show the state of the outline, I’d like a solid right triangle and down triangle.

Things I have tried

I’ve tried this css snippet that does not work:

  .collapsible-item-collapse {
    padding: 2px 15px 2px 15px;
    left:1.5px;
  }
   div.collapsible-item-inner{
    position:relative;
    padding-left: 15px;

   }
  .outline .collapsible-item-children {
    margin-left: 20px;
    border-left: 1px solid rgba(118,158,165,0.2);
    border-radius: 4px;
    transition:all 0.5s ease-in-out;
  }
  .outline .collapsible-item-children:hover {
    border-left-color: rgba(118,158,165,0.4);
  }
svg.svg-icon.right-triangle {
//    width: 24;
//    height: 24;
    fill: yellow !important;  //trying to at least change the color to yellow but that not work
//    stroke: currentcolor !important;
//    stroke-width: 2;
//    stroke-linecap: round;
//    stroke-linejoin: round;
}

I am using the Minimal theme.
Plugins:
Lapel
Dataview
Outliner
Style Settings