@theia/core/src/browser/style/tooltip.css

Theia is a cloud & desktop IDE framework implemented in TypeScript.

/********************************************************************************
 * Copyright (C) 2021 Arm and others.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the Eclipse
 * Public License v. 2.0 are satisfied: GNU General Public License, version 2
 * with the GNU Classpath Exception which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
 ********************************************************************************/

.theia-tooltip {
  color: var(--theia-editorHoverWidget-foreground) !important;
  background: var(--theia-editorHoverWidget-background) !important;
  border: 1px solid !important;
  border-color: var(--theia-editorHoverWidget-border) !important;
}

/* Hide tooltip arrow */
.theia-tooltip::before,
.theia-tooltip::after {
  border: none !important;
}