core/themes/claro/css/components/messages.pcss.css
/**
 * Messages.
 *
 * @todo revisit this after https://www.drupal.org/project/drupal/issues/3078400
 *   has been resolved.
 */

:root {
  --messages-bg-color: #353641;
  --messages-fg-color: var(--color-white);
  --messages-border-radius: 2px;
  --messages-border-width: 5px;
  --messages--status-color: #42a877;
  --messages--warning-color: #e0ac00;
  --messages--error-color: #e34f4f;
  --messages__link-color: var(--color-sunglow);
  --messages__link--hover-color: var(--color-white);
  --messages__icon-size: 1rem;
  --messages__text-margin: calc(var(--messages__icon-size) + var(--space-l));
}

.messages-list {
  margin-block: calc(var(--space-m) + var(--space-l));
  padding: 0;
  list-style: none;
}

.field .messages-list,
.form-wrapper .messages-list {
  margin-block-end: 0;
}

.messages {
  overflow: auto; /* Required to prevent text clipping. */
  box-sizing: border-box;
  margin-block: var(--space-m);
  padding-block: var(--space-l) 2rem;
  padding-inline: calc(var(--space-l) - 5px) var(--space-l);
  color: var(--messages-fg-color);
  border-width: 0 0 0 var(--messages-border-width); /* LTR */
  border-style: solid;
  border-color: var(--messages-bg-color);
  border-radius: var(--messages-border-radius);
  background-color: var(--messages-bg-color);

  & a {
    text-decoration: underline;
    color: var(--messages__link-color);

    &:hover {
      color: var(--messages__link--hover-color);
    }
  }

  & pre {
    margin: 0;
  }

  [dir="rtl"] & {
    border-right-width: var(--messages-border-width);
    border-left-width: 0;
  }
}

.messages--error {
  border-color: var(--messages--error-color);

  & .messages__header {
    background: url(../../images/icons/e34f4f/crossout.svg) no-repeat center left;
  }
}

.messages--status {
  border-color: var(--messages--status-color);

  & .messages__header {
    background: url(../../images/icons/42a877/checkmark.svg) no-repeat center left;
  }
}

.messages--warning {
  border-color: var(--messages--warning-color);

  & .messages__header {
    background: url(../../images/icons/e0ac00/exclamation.svg) no-repeat center left;
  }
}

.messages__title {
  margin-block: 0;
  margin-inline: var(--messages__text-margin) 0;
  font-size: var(--font-size-base);
}

.messages__header {
  display: flex;
  align-items: center;
  margin-block-end: var(--space-m);

  [dir="rtl"] & {
    background-position: center right;
  }
}

@media screen and (min-width: 48rem) {
  .messages__content {
    margin-inline-start: var(--messages__text-margin);
  }
}

.messages__list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.messages__item + .messages__item {
  margin-block-start: var(--space-s);
}
