Streamline design only provide in PowerStore 1.x
The Streamline design was provided as an additional design with PowerStore v1. This is not included with PowerStore v2 and owners of this version will not see it in their Download Center.
The Customizing your PowerStore site's design How To is located under Archived documentation for this reason. In most cases, those instructions will no longer work for customizing a PowerStore 2 layout.
PowerStore 2 has been designed and developed for easy modification to the text, layout, and colors. Everything, including most buttons and links use CSS for their styling, instead of images. This will allow you to modify the CSS values to achieve any color scheme you desire.