Slideout menu always open

Hello, 
I was trying to make the slideout menu open by default and add the ability to close it using the close icon. I was able to make it always open, but the close icon is not working at all. I used the following code:
/* slideout always open */
#generate-slideout-menu:not(.is-open) {
 transform: translate3d(265px,0,0);
background-color: white;
}

One more thing, after using the above code the menu items are not clickable anymore, So, I can't access the submenu items. I used the following code but it seems that it is supporting the hover function only and not the clickable function.

.slideout-navigation .sub-menu {
     display: block !important;
}