isicmexico
Yes, you can open the file: /templates/ja_mono/less/variables.less
At approx line 296, you find this variable:
@screen-hd: 1400px;
change it to:
@screen-hd: 1367px;
This change is applied to LESS file so you will need to compile less to css to see the change. Go to Backend > Extensions > Templates > JA Mono > hit the button to compile less to css: https://prnt.sc/pb4z3e
But REMEMBER to backup all current CSS files first as compiling less to css will override current css files.
Regards