1. If the theme gets updated, will I lose my colours?
Fevered is exactly right about under what conditions your CSS tweaks will be preserved or lost. Let us know if you have any questions about that. There is a custom CSS editor built into Jetpack so if you’re already running that plugin it’s an easy route. Once activated, you’d then add your custom CSS in the new stylesheet editor that’ll appear in your dashboard, under Appearance > Edit CSS.
This should change the font colour of your site title and site description (tagline):
.site-header h1.site-title a {
color: #bb00bb;
}
.site-header .site-description {
color: #bb00bb;
}
Purple colour is just for example – change to whatever you like. If you’re looking to change other elements within the header, let us know which so we can help. You can also right-click the element and use a browser inspector like the ones built into Chrome or Firefox to find the element to target with CSS.