decrease sidebar width?

You can add this to your child style.css or Custom CSS plugin:

.widget-area {
    width: 20.7417%;
}

.site-content {
    width: 71.1042%;
}

i dont use child css ..i want to do it directly without using any plugin

If you do it directly you may have trouble later on when the theme is updated. If you dont want to use child theme, it is fine. You can install the Custom CSS plugin and add this code using it.

okay i got it..thanks….
add banner on each post automatically with paragraph like this one
https://www.supportivehands.net/cheap-credit-card-gateways-for-small-businesses
how can i do this??