Hi Mark.
I'm still a total noob when it comes to css and html and it can get really frustrating as you say.
One thing I have learned is to always apply a top level class when doing things like that and then put that class in front of everyone single css block.
For example put a css class called .myDashboard on the top level panel / querie where you want to customize the css.
then in your css file make sure you prepend. myDashboard before every selector you are modifying. For instance... instead of saying:
tr {
height: 20px;
padding: 5px;
}
you will say:
.myDasboard tr {
height: 20px;
padding: 5px;
}
this way you make sure the change is only applied to tr selectors that are children directly or indirectly of the .myDashboard class.
Just my 2 cents. hope that helps point in the right direction.
regards
Hein