After close examining, not 300k lines but there are around 3-4 CSS properties that you need to override:
.navbar-collapse.collapse {
display: block!important;
}
.navbar-nav>li, .navbar-nav {
float: left !important;
}
.navbar-nav.navbar-right:last-child {
margin-right: -15px !important;
}
.navbar-right {
float: right!important;
}
And with this your menu won't collapse.
EXPLANATION
The four CSS properties do the respective:
The default .collapse property in bootstrap hides the right-side of the menu for tablets(landscape) and phones and instead a toggle button is displayed to hide/show it. Thus this property overrides the default and persistently shows those elements.
For the right-side menu to appear on the same line along with the left-side, we need the left-side to be floating left.
This property is present by default in bootstrap but not on tablet(portrait) to phone resolution. You can skip this one, it's likely to not affect your overall navbar.
This keeps the right-side menu to the right while the inner elements (li) will follow the property 2. So we have left-side float left and right-side float right which brings them into one line.