questa è la prima immagine!!!
questa è la seconda!!

Web page testing is part of building a successful web site

Web page testing is part of building a successful web site

Web page testing is part of building a successful web site

Web page testing is part of building a successful web site

Web page testing is part of building a successful web site
Web page testing is part of building a successful web site

.col-xs -> Less than 768px
.col-sm -> Tablets 768px and Up
.col-md -> Desktops 992px and Up
.col-lg -> Large Desktops 1200px and Up

.visible-xs .visible-sm .visible-md .visible-lg
.hidden-xs .hidden-sm .hidden-md .hidden-lg
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2
3
4
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I'm content!
I'm content!
I'm content!
I'm content!
I'm content!
I'm content only visible on large devices!
A
B
C
... div row -> no-gutter
... div row -> no-gutter
... div row -> no-gutter
-> container-fluid
-> container-fluid
-> container-fluid
-> container-fluid

Cras eu elementum nibh Proin iaculis enim Aenean pretium purus Cras eu elementum nibh Proin iaculis enim Aenean pretium purus Proin iaculis enim
Cella 5 Cella 6 Cella 7 Cella 8 Cella 5 Cella 6 Cella 7 Cella 8
Cella 9 Cella 10 Cella 11 Cella 12 Cella 9 Cella 10 Cella 11 Cella 12
Cella 13 Cella 14 Cella 15 Cella 16 Cella 13 Cella 14 Cella 15 Cella 16
Cella 17 Cella 18 Cella 19 Cella 20 Cella 17 Cella 18 Cella 19 Cella 20
Cella 17 Cella 18 Cella 19 Cella 20 Cella 17 Cella 18 Cella 19 Cella 20
Cella 17 Cella 18 Cella 19 Cella 20 Cella 17 Cella 18 Cella 19 Cella 20