http://bit.ly/get_your_divi_on

https://www.elegantthemes.com/blog/divi-resources/how-to-identify-divis-responsive-breakpoints-and-fine-tune-your-designs-with-media-queries

Here is a list of the main media queries used in the Divi Theme. You can use this as a helpful template for your custom CSS.

/*** Responsive Styles Large Desktop And Above ***/
@media all and (min-width: 1405px) {

}

/*** Responsive Styles Standard Desktop Only ***/
@media all and (min-width: 1100px) and (max-width: 1405px) {

}

/*** Responsive Styles Tablet And Below ***/
@media all and (max-width: 980px) {

}

/*** Responsive Styles Tablet Only ***/
@media all and (min-width: 768px) and (max-width: 980px) {

}

/*** Responsive Styles Smartphone Only ***/
@media all and (max-width: 767px) {

}

/*** Responsive Styles Smartphone Portrait ***/
@media all and (max-width: 479px) {

}