Fix more regressions

Problem/Motivation

The QA reported about several regressions:

• [Small Y] Distance between the cards is bigger on the mobile devices than on the design
• [Small Y] The font-weight of the description of the Staff block is wrong
• [Small Y] The staff card isn't centred
• [Small Y] The color of the title of the testimonial block is wrong
• [Small Y] The width of the staff cards when 2 cards per row option is applied is different from the design
• [Small Y] It is allowed to add up to 4 testimonial items in the block
• [Small Y] Menu is hidden under the alert or Banner image

Proposed resolution

Let's fix them.