fuse-angular/src/app/main/angular-material-elements/example-viewer/example-viewer.theme.scss

@mixin example-viewer-theme($theme) {

    $background: map-get($theme, background);
    $foreground: map-get($theme, foreground);

    example-viewer {

        .example-viewer-header {
            color: map-get($foreground, secondary-text);
            background: map-get($background, app-bar);
            border-bottom-color: map-get($foreground, divider);
        }

        .example-viewer-source {

            .tab-content {

                .tab {

                    .example-source {
                        border-bottom-color: map-get($foreground, divider);
                    }
                }
            }
        }
    }
}