Hello There,
Thanks for writing in!
1.) To change the content in single product page active tab panes, please add the following CSS code in the X > Theme Options > Global CSS (http://prntscr.com/evui3r)
.x-nav-tabs>li.active a{
color: red;
}
.x-tab-content .x-tab-pane.active {
color: red !important;
}
This code may not work in your description because all the content text were wrap with a span element that has inline styles in it. You may need to edit it.
2.) To change the font color of the prices, you may use this code:
.woocommerce .price,
.woocommerce li.product .entry-header .price>.amount,
.woocommerce li.product .entry-header .price>ins>.amount {
color: red;
}
Feel free to change the color values as it only serve as an example code.