Bootstrap enforces a grid system where each row consists of 12 columns, with each column being contained within a single row.
If you desire three columns, it is important to designate that each column should occupy a width equivalent to 4
columns since 12 / 3 = 4
. This can be achieved by assigning the class name col-sm-4
.
The prefix col-sm-
for columns pertains to screen sizes labeled as 'Small' and naturally defaults to a precise width of 576px
:
https://i.sstatic.net/izNLQ.png
An illustration of this concept is provided below:
.one {
background: red;
}
.two {
background: blue;
}
.three {
background: green;
}
.col-sm-4 {
height: 50px;
}
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" integrity="sha384-rwoIResjU2yc3z8GV/NPeZWAv56rSmLldC3R/AZzGRnGxQQKnKkoFVhFQhNUwEyJ" crossorigin="anonymous">
<div class="row">
<div class="col-sm-4 one"></div>
<div class="col-sm-4 two"></div>
<div class="col-sm-4 three"></div>
</div>
This example demonstrates the implementation in practice.
Trust this clarifies things for you! :)