about svg. Q1: when setting up layout size, height & width, do we need an extra layout for some things different from the first layout. ie two layouts? Q2: what is the purpose of the size? how does it affect graphics in it? Q3: how to treat problem of over lapping or/and over ridding?
Things shouldn't over ride when on block elements, so use things like the <div> tags. You could also use z-index in your style attributes or on your car to help. This chooses the order of things. The purpose of the size just depends on what you want, say you had a large image but wanted it as a small icon, you could change the size. Making it bigger may distort the image slightly though, depending on the quality that is. Making it smaller will just increase the pixel density, if anything, making it slightly better quality.
27062019 Shah and all: It was when learning svg had I played the codes, and posted these questions. SVG object can not animate; an object when drawn with attributes can not be changed. Therefore z-index can switch multiple objects, but still can fade in and out with time factor.