Q: What is mb-0?
Best answer:
Bootstrap response having wide margins and padding utility classes. They apply to all breakpoints:
xs(< = 576px)，sm(> = 576px)，md(> = 768px)，lg(> = 992px)或xl(> = 1200px))
The class has the following format:
{property} {sides} – {size} for xs& {property} {sides} – {breakpoint} – {size}表示sm，md，lg和xl。
m - margined
p - Set Fill
t - Set margin-top or padding-top
b - Set margin-bottom or padding-bottom
l - Set margin-left or padding-left
r - Set margin-right or padding-right
x - Set padding-left and padding-right, or margin-left and margin-right
y - Set padding-top and padding-bottom, or margin-top and margin-bottom
Blank - margins provided or filled in all four sides of elements
0 - The margin is set to 0 or filler
1 - margin or fill to .25rem (font-size if compared to 16px 4px)
2 - margin or fill to .5rem (compared to if the font size is 16px 8px)
3 - The margin is set to 1 rem or filler (if the font size is 16px, compared 16px)
4 - margin or fill to 1.5rem (if the font size is 16px, compared 24px)
5 - margin or fill to 3rem (font-size if compared to 16px 48px)