mobile dispaly: active sublevel menu

hi
i have joomla 3.8.8 all mdolues, plugs, components are updated.
use your mod_jux_megamenucss3 ,to display mobile menu.
all is well, except that the sublevel menus are opened, as soon as it switches to mobile version (1000px).
2nd/3rd levels are closed at less than 750px width.
where can i edit this to set it to 1000px, i mean't that first level should be shown, but 2nd and 3rd level not automatically opened, should only open if clicked by arrows, hope its understandable

i tried in modules/mod_jux_megamenucss3/assets/css/style/style_responsive.css. as well as in
modules/mod_jux_megamenucss3/assets/css/style/style.css
changed there
@media screen and (max-width:768px to > 1000px
but won't work

not sure if this has to do with 2nd/3rd level open or nor, don't think so

hope you have an idea

regards
webart-workers