wagtail/client/scss/components/_help-block.scss

// Help text formatters
.help-block {
    padding: 1em;
    margin: 1em 0;
    clear: both;
    color: $color-text-base;

    p {
        margin-top: 0;

        &:last-child {
            margin-bottom: 0;
        }
    }

    a {
        color: $color-link;
    }
}

.help-info,
.help-warning,
.help-critical {
    border-radius: 3px;
    padding-left: 3.5em;
    position: relative;

    &:before {
        font-family: wagtail;
        position: absolute;
        left: 1em;
        top: 0.7em;
        content: map-get($icons, 'help');
        font-size: 1.4em;
    }
}

.help-info {
    background-color: lighten($color-blue, 30%);

    &:before {
        color: $color-blue;
    }
}

.help-warning {
    background-color: lighten($color-orange, 30%);

    &:before {
        color: $color-orange;
        content: map-get($icons, 'warning');
    }
}

.help-critical {
    background-color: lighten($color-red, 40%);

    &:before {
        color: $color-red;
        content: map-get($icons, 'warning');
    }
}

// Media for Windows High Contrast
@media (forced-colors: $media-forced-colours) {
    .help-block {
        forced-color-adjust: none;
        border: 1px solid $system-color-link-text; // ensure visible separation in Windows High Contrast mode
        background-color: transparent;
        color: $color-white;

        &:before {
            color: currentColor;
        }
    }

    .help-warning {
        color: $color-text-warning-forced-color;
        border-color: $color-text-warning-forced-color;
    }

    .help-critical {
        color: $color-text-error-forced-color;
        border-color: $color-text-error-forced-color;
    }
}