Hi there,

Thank you for getting in touch with us.

In order to make single post less wide you can enable the sidebar under Appearance → Customize → Posts → Layout with sidebar or you can add this css under Appearance → Customize → Additional CSS:

.single-post .entry {
    width: 70%;
}

In order to make more wide look in blog page try this css:

.blog .main-column.col-md-9 {
    width: 100%;
}

Hope that helps. Thank you for your time in this.

Best regards

I’m glad to hear that 🙂

Feel free to reach out if you need anything.