The following CSS frameworks now work out of the box, which means there should be no clashes between the Qlik Sense CSS styles and the styles included in the common CSS framework:
Add the following reference to your mashups:
<link rel="stylesheet" href="https://QSE_domain/resources/autogenerated/qlik-styles.css"> Updating CSS links in existing mashups
If your mashups were built using Qlik Sense 2.1 or earlier, you should replace the following references:
<link rel="stylesheet" href="../../resources/autogenerated/qlikui.css">
<link rel="stylesheet" href="../../resources/assets/client/client.css" media="all">with the following:
<link rel="stylesheet" href="https://QSE_domain/resources/autogenerated/qlik-styles.css">