Hello, @Darul Muqarrabin Malaysia,
1. You have to go to XStore >> Theme Settings >> WooCommerce >> Single Product Page Builder and edit the Coss Sells element, from there change the border color: https://postimg.cc/gnb76HZX
2. For Filter By Price, You have to change the Primary Color of the site from XStore >> Theme Settings >> Styling/Colors: https://postimg.cc/wRjQh3gr
3. Same as in point No 2, for the Popup Fake Sale: https://postimg.cc/jWhfZKgY
4. For the Quick View, You can change it from Theme Settings >> Theme Custom CSS >> Global CSS: https://postimg.cc/Tpmptf1N
5. Continue Reading, Same as in point No 2, the site Main Color will change it: https://postimg.cc/K43zYxPc
6. Other Posts by, Same as in point No 2, the site Main Color will change it: https://postimg.cc/nMqJ5zKm
7. Categories Sidebar border color, you can change it from Theme Settings >> Theme Custom CSS >> Desktop CSS as per your requirements: https://postimg.cc/62fN8bp0
Regards 8Themes Team.