Our procedure is generally to get what we want on full screen. All those css changes would go in the stylesheet_zcustom.css There is no need to touch any other stylesheet for this.

Next, respsonsive_mobile.css in the bottom of the portrait portion to fix minor items needed for portrait mobiles. Then the same for the landscape mobile.

Next, is the responsive_tablet.css in portrait in landscape.

Only then do we start looking at the desktop changes that happen at various widths. If any changes are needed at various widths above those covered by mobile or tablet, we make those in responsive_default.css.

It's always good to enter something to make it easy to find your changes when you need them later. Something like
Code:
/*  SVDB  */
can be added on the line that you change or add.