progressbar.css

/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

.monaco-progress-container {
	width: 100%;
	height: 2px;
	overflow: hidden; /* keep progress bit in bounds */
}

.monaco-progress-container .progress-bit {
	width: 2%;
	height: 2px;
	position: absolute;
	left: 0;
	display: none;
}

.monaco-progress-container.active .progress-bit {
	display: inherit;
}

.monaco-progress-container.discrete .progress-bit {
	left: 0;
	transition: width 100ms linear;
}

.monaco-progress-container.discrete.done .progress-bit {
	width: 100%;
}

.monaco-progress-container.infinite .progress-bit {
	animation-name: progress;
	animation-duration: 4s;
	animation-iteration-count: infinite;
	transform: translate3d(0px, 0px, 0px);
	animation-timing-function: linear;
}

.monaco-progress-container.infinite.infinite-long-running .progress-bit {
	/*
		The more smooth `linear` timing function can cause
		higher GPU consumption as indicated in
		https://github.com/microsoft/vscode/issues/97900 &
		https://github.com/microsoft/vscode/issues/138396
	*/
	animation-timing-function: steps(100);
}

/**
 * The progress bit has a width: 2% (1/50) of the parent container. The animation moves it from 0% to 100% of
 * that container. Since translateX is relative to the progress bit size, we have to multiple it with
 * its relative size to the parent container:
 * parent width: 5000%
 *    bit width: 100%
 * translateX should be as follow:
 *  50%: 5000% * 50% - 50% (set to center) = 2450%
 * 100%: 5000% * 100% - 100% (do not overflow) = 4900%
 */
@keyframes progress { from { transform: translateX(0%) scaleX(1) } 50% { transform: translateX(2500%) scaleX(3) } to { transform: translateX(4900%) scaleX(1) } }