hi
1 each article don't have the same number of image or lines text ...so nothing can be vertical align with the css you use .
2 You use a sprite for "Plaats in de winkelwagen" that overlap the width of the container in some case ( MQ) .
3 color fore/back ground
The top right corner should be to a lighter color . when thetop image is use , the background is white , the top right corner could not be white !!
I like the way you cut the original image in the home page refer to each Mediaqueries ranges .
The issues ( 1 2 ) appear during many mediaqueries range in some case .
Gantry is more than a template it is an IDE integration in the backend with many tool for deigner and developper . Gantry has many predefine mediaqueries , but mediaqueries breakpoints must be choose refer to broken design when width browser decrease not refer to predefine device screen . See the capture screen about mediaqueries range , and do you know a- for each range what occur in each range whithout have a look to each range definition ? or b- do you know in wich range you make some modification ?
When i begin joomla i was thinking that i could begin to learn gantry first but discover i need to undertand the basic go low level ( css html js ) before go to high level like gantry. If you use high level tool ; you have to know the low level tools/techniques that is use by the high level tool .
I really think joomla should be agnostic about CSS framework and joomla framework ( larabee) !!
when you understand css js html you can take the code from one website and make your's ( inspire not thief ).
Hope this ll helpfull .