1:
In the clock.js file I add these lines to the bottom of these sections:

/************************************
* Create wrappers for analog and digital clock
*/
const analogBackground = document.createElement("div");
analogBackground.className = "clock-grid-background";

/****************************************************************
* Create wrappers for ANALOG clock, only if specified in config
*/
clockFace.appendChild(analogBackground);

2:
Added this section to the clock_styles.css:
Note the “z-index: 0;”

.clock-grid-background {
  position: absolute;
  display: block;
  z-index: 0;
}

I then added “z-index: 99;” to the following sections to make sure they stay on top:
.clock-circle
.clock-face
.clock-face::after
.clock-hour
.clock-minute
.clock-second

Added this code to the custom.css file:

.clock-grid-background {
  -webkit-mask: url('apple-fresh-fruit-svgrepo-com.svg') center/cover no-repeat;
  //mask: url('apple-fresh-fruit-svgrepo-com.svg');
  display: block;
  margin: auto;
  margin-top: 60px;
  margin-left: 65px;
  height: 120px;
  width: 120px;
  background-color: var(--use_color);
}

In the screen shot below I left my clock the same as before with ‘z-index: 0’ on the apple and ‘z-index: 99’ on all the other classes of the clock. I then set my calendar module to “fullscreen_above” to see what would happen.

Not easy to see in the screen shot but all of the components of the clock that have a z-index are on top of the calendar and the date which doesn’t have any z-index values is underneath the calendar. So it would appear that any z-index value, even 0, puts those components on top of “fullscreen_above”. So yes, it should be used carefully because it will peek through.

{
	module: "clock",
	position: "top_left",
	config: {
		displayType: "analog",
		displaySeconds: false,
	}
},
{
	module: "calendar",
	header: "US Holidays",
	position: "fullscreen_above",
	config: {
		calendars: [
			{

I’m still working on it because I’d like to have a solution that doesn’t require any code changes to the module files. I’d like something that only requires using the custom.css file.

1:
In the clock.js file I add these lines to the bottom of these sections:

/************************************
* Create wrappers for analog and digital clock
*/
const analogBackground = document.createElement("div");
analogBackground.className = "clock-grid-background";

/****************************************************************
* Create wrappers for ANALOG clock, only if specified in config
*/
clockFace.appendChild(analogBackground);

2:
Added this section to the clock_styles.css:
Note the “z-index: 0;”

.clock-grid-background {
  position: absolute;
  display: block;
  z-index: 0;
}

I then added “z-index: 99;” to the following sections to make sure they stay on top:
.clock-circle
.clock-face
.clock-face::after
.clock-hour
.clock-minute
.clock-second

Added this code to the custom.css file:

.clock-grid-background {
  -webkit-mask: url('apple-fresh-fruit-svgrepo-com.svg') center/cover no-repeat;
  //mask: url('apple-fresh-fruit-svgrepo-com.svg');
  display: block;
  margin: auto;
  margin-top: 60px;
  margin-left: 65px;
  height: 120px;
  width: 120px;
  background-color: var(--use_color);
}