A spacing scale is a short list of allowed gaps, built from one base value such as 4 or 8 pixels.
Consistent spacing reads as order. Random gaps make even good designs look busy.
Mobile-first design starts with the phone screen and adds to it for larger screens, instead of squeezing a desktop page down.
Learn the termThe nested border-radius rule says an inner corner's radius should equal the outer radius minus the padding between them.
Learn the termA touch target is the tappable area of a button, link or control.
Learn the termSpacing scale is part of a normal project here. Tell me where you are and I'll suggest the first three fixes.