diagram-js-code-editor/assets/diagram-js-code-editor.css

 .djs-editor {
   position: absolute;
   top: 90px;
   right: 20px;
   background-color: rgba(255, 255, 255, 0.9);
   color: rgb(0, 0, 0);
   border: solid 1px #CCC;
   border-radius: 2px;
   box-sizing: border-box;
   user-select: none;
   -moz-user-select: none;
   -ms-user-select: none;
   -webkit-user-select: none;
 }

 .djs-editor:not(.enabled) {
   color: #CCC;
   pointer-events: none;
 }

 .djs-editor:not(.open) {
   overflow: hidden;
 }

 .toolbar {
   display: none;
   width: 50%;
   height: 35px;
   list-style-type: none;
   padding: 0;
 }

 .djs-editor.open .toolbar {
  display: block;
  text-align: left;
  line-height: 35px;
}
 
.toolbar {
  width: 100%;
  float: left;
  margin: 0;
  padding: 0;
  background-color: #f2f2f2;
  border-bottom: 1px solid #ccc;
  border-top: 1px solid #ccc;
}
.toolbar > div {
  float: left;
  display: block;
  border-right: 1px solid #ccc;
  padding: 0px 15px;
}

.toolbar div {
  text-decoration: none;
  font-weight: bold;
  color: #069;
}

.toolbar div:hover {
  color: #c00;
  background-color: #fff;
}

.toolbar div.active {
  background-color: rgb(201, 205, 248);
}

.dropdown .trigger {
  border: none;
  padding: 0px;
}

.dropdown {
  position: relative;
}

.dropdown .dropdown-content {
  display: none;
  position: absolute;
  background-color: #f2f2f2 !important;
  z-index: 1;
}

.dropdown:hover .dropdown-content {
  display: block;
}

.dropdown-content .sub-trigger {
  text-decoration: none;
  padding: 0 0 0 15px;
  border-bottom: 1px solid #ccc;
  display: block;
}

.description {
  display: none;
  color: #000 !important;
  min-width: 250px;
  background-color: #f2f2f2 !important;
}

.dropdown-content .sub-trigger{
position: relative;
}
.dropdown-content .sub-trigger:hover .description {
  top: 0;
  left: 100%;

  position: absolute;
  display: block;
}

 #run_btn {
   font-family: "Material Icons", sans-serif;
 }

 #run_btn:before {
   content: "build";
 }

 .djs-editor .ide {
   display: none;
   width: 100%;
   min-width: 420px;
   height: 280px;
 }

 .djs-editor.open .ide {
   display: block;
 }

 .djs-editor:not(.open) .toggle {
   width: 46px;
   height: 46px;
   line-height: 46px;
   content: "dvr" !important;
   text-align: center;
 }

 .djs-editor.open .toggle:before {
   font-family: "Material Icons", sans-serif;
   content: "close" !important;
   font-size: 24px;
 }

 .djs-editor:not(.open) .toggle:before {
   font-family: "Material Icons", sans-serif;
   content: "dvr" !important;
   font-size: 24px;
 }

 .djs-editor .toggle:before {
   content: attr(title);
 }

 .djs-editor.open .toggle {
   position: absolute;
   right: 0;
   padding: 6px;
   z-index: 1;
 }