CSS

The context menu can be styled using CSS.

Default CSS Theme

This is the definition of the default theme ("menu_default") which is built in:

.menu_default_main {
  user-select:none;
  font-family: -apple-system,system-ui,BlinkMacSystemFont,'Segoe UI',Roboto,'Helvetica Neue',Arial,sans-serif;
  font-size: 13px;
  border: 1px solid #dddddd;
  background-color: white;
  padding: 0px;
  cursor: default;
  background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB4AAAABCAIAAABG0om7AAAAKXRFWHRDcmVhdGlvbiBUaW1lAHBvIDEwIDUgMjAxMCAyMjozMzo1OSArMDEwMGzy7+IAAAAHdElNRQfaBQoUJAesj4VUAAAACXBIWXMAAA7DAAAOwwHHb6hkAAAABGdBTUEAALGPC/xhBQAAABVJREFUeNpj/P//PwO1weMnT2RlZAAYuwX/4oA3BgAAAABJRU5ErkJggg==);
  background-repeat: repeat-y;
  xborder-radius: 5px;
  -moz-box-shadow:0px 2px 3px rgba(000,000,000,0.3),inset 0px 0px 2px rgba(255,255,255,0.8);
  -webkit-box-shadow:0px 2px 3px rgba(000,000,000,0.3),inset 0px 0px 2px rgba(255,255,255,0.8);
  box-shadow:0px 2px 3px rgba(000,000,000,0.3),inset 0px 0px 2px rgba(255,255,255,0.8);
}

.menu_default_main, .menu_default_main *, .menu_default_main *:before, .menu_default_main *:after {
  box-sizing: content-box;
}

.menu_default_title {
  background-color: #f2f2f2;
  border-bottom: 1px solid gray;
  padding: 4px 4px 4px 37px;
}

.menu_default_main a {
  padding: 2px 2px 2px 35px;
  color: black;
  text-decoration: none;
  cursor: default;
}

.menu_default_main.menu_default_withchildren a {
  padding: 2px 35px 2px 35px;
}

.menu_default_main a img {
  margin-left: 6px;
  margin-top: 2px;
}

.menu_default_item_text {
  display: block;
  height: 20px;
  line-height: 20px;
  overflow:hidden;
  padding-left: 2px;
  padding-right: 20px;
  white-space: nowrap;
}

.menu_default_main a:hover {
  background-color: #f3f3f3;
}

.menu_default_main div div {
  border-top: 1px solid #dddddd;
  margin-top: 2px;
  margin-bottom: 2px;
  margin-left: 28px;
}

.menu_default_main a.menu_default_item_disabled {
  color: #ccc;
}

.menu_default_item_haschildren.menu_default_item_haschildren_active {
  background-color: #f3f3f3;
}

.menu_default_item_haschildren a:before {
  content: '';
  border-width: 5px;
  border-color: transparent transparent transparent #666;
  border-style: solid;
  width: 0px;
  height:0px;
  position: absolute;
  right: 5px;
  margin-top: 5px;
}

.menu_default_item_icon {
  position: absolute;
  top:0px;
  left: 0px;
  padding: 2px 2px 2px 8px;
}

.menu_default_item a i {
  height: 20px;
  line-height: 20px;
}

.menu_default_item .menu_default_item_symbol {
  width: 18px;
  height: 18px;
  color: #999;
  margin-left: 6px;
  margin-top: 2px;
}

JavaScript

You can apply a custom CSS theme using DayPilot.Menu.theme property