Include a set of default type styles…

…so you can create a page containing standard elements (eg p, h1, h2,
h3 etc) and it typesets nicely
Remove .performance-platform-outer

.performance-platform-outer wasn’t doing anything we couldn’t do with
padding on the parent element
$govuk-blue on border-top and border-bottom

Replace PP $primary-colour with $govuk-blue because we are one GOV.UK
Reduce size of impact number on desktop