Embed the report designer in JavaScript, load a template, and connect its editing and save actions.

Designer setup. Configure the designer, load the report template, process its callbacks, and connect the save action to the application.
var options = new Stimulsoft.Designer.StiDesignerOptions();
options.appearance.theme = Stimulsoft.Designer.StiDesignerTheme.Office2022WhiteBlue;

var designer = new Stimulsoft.Designer.StiDesigner(options);

function setTheme(theme) {
    designer.setTheme(theme);
}
The initial theme is set in options.appearance.theme from the StiDesignerTheme list, and designer.setTheme(...) changes it on the fly, so users can pick a light or dark appearance that matches your application.
На скриншоте ниже Вы можете увидеть результат выполнения данного кода:

Changing the Designer Theme