WhiteSur-gtk-theme/src/other/firefox/common/parts/infobar.css

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

:host(.infobar) {
  --info-bar-background-color: light-dark(var(--color-white), var(--gnome-tabbar-tab-active-background)) !important;
  --info-bar-text-color: light-dark(var(--color-gray-100), var(--color-gray-05)) !important;
  position: relative;

  &::before {
    content: "";
    display: block;
    width: 2px;
    position: absolute;
    top: 0;
    inset-inline-start: 0;
    height: 100%;
    border-start-start-radius: 4px;
    border-end-start-radius: 4px;
  }

  .container {
    /* Don't let lwthemes set a text-shadow. */
    text-shadow: none;
    padding-block: 3px;
    align-items: center;
  }

  .content {
    gap: 0 12px;
    height: fit-content;
  }

  .close {
    margin-block: 2px;
    margin-inline-start: 8px;
    align-self: flex-start;
  }
}

@media (prefers-contrast) {
  :host(.infobar)::before {
    background-color: CanvasText;
  }
}

@media not (prefers-contrast) {
  :host(.infobar) {
    box-shadow: 0 1px 2px rgba(48, 48, 48, 0.1);
    background-color: var(--gnome-tabbar-tab-active-background) !important;
    color: var(--info-bar-text-color) !important;

    &::before {
      background-image: linear-gradient(0deg, #9059ff 0%, #ff4aa2 52.08%, #ffbd4f 100%);
    }
  }
}

:host([message-bar-type=infobar]:first-of-type) {
  margin-top: 4px;
}

:host([message-bar-type=infobar]) {
  margin: 0 4px 4px;
}

::slotted(.notification-button-container) {
  gap: 8px;
  display: inline-flex;
}

::slotted(.text-link) {
  margin: 0 !important;
}

img.inline-icon {
  /* Align inline icon images in the message content */
  vertical-align: middle;
  /* Ensure they get the right fill color. */
  -moz-context-properties: fill;
  fill: currentColor;
}

strong {
  font-weight: var(--font-weight-bold);
}

/* type="system" infobar styles */

:host([type=system]) .icon {
  display: none;
}

:host([type=system]) .content {
  margin-inline-start: 0;
}