Check out example codes for "bootstrap grid". It will help you in understanding the concepts better.
Code Example 1
col-12 col-sm-4 col-md-3 col-lg-12 col-xl-12
Code Example 2
<!----------------------- BOOTSTRAP GRID SYSTEM ------------------------>
This code will create 4 boxes placed side by side, which will be
dynamically positioned, according to the size of the screen. We define
the following behavior:
<!-- Desktop Display: we have 4 columns per row (each occupies 3 units out of 12) -->
class = "col-lg-3" <!-- display large with 12/3 = 4 columns -->
<!-- Tablet Display: we have 3 columns per row (each occupies 4 units out of 12) -->
class = "col-md-4" <!-- display medium with 12/4 = 3 columns -->
<!-- Mobile Display: we have 2 columns per row (each occupies the 6 units of 12) -->
class = "col-sm-6" <!-- display small with 12/6 = 2 columns -->
<!-- CODE -->
<div class="row">
<div class="col-lg-3 col-md-4 col-sm-6" style="background-color:red; border:1px solid black;">
One of four columns
</div>
<div class="col-lg-3 col-md-4 col-sm-6" style="background-color:yellow; border:1px solid black;">
One of four columns
</div>
<div class="col-lg-3 col-md-4 col-sm-6" style="background-color:green; border:1px solid black;">
One of four columns
</div>
<div class="col-lg-3 col-md-4 col-sm-6" style="border:1px solid black;">
One of four columns
</div>
</div>
Code Example 3
<div class="row">
<div class="col-md-4">.col-md-4</div>
<div class="col-md-4 offset-md-4">.col-md-4 .offset-md-4</div>
</div>
<div class="row">
<div class="col-md-3 offset-md-3">.col-md-3 .offset-md-3</div>
<div class="col-md-3 offset-md-3">.col-md-3 .offset-md-3</div>
</div>
<div class="row">
<div class="col-md-6 offset-md-3">.col-md-6 .offset-md-3</div>
</div>
Code Example 4
<div class="container">
<div class="row">
<div class="col-sm">
One of three columns
</div>
<div class="col-sm">
One of three columns
</div>
<div class="col-sm">
One of three columns
</div>
</div>
</div>
Code Example 5
The Bootstrap grid system has four classes:
xs (for phones - screens less than 768px wide)
sm (for tablets - screens equal to or greater than 768px wide)
md (for small laptops - screens equal to or greater than 992px wide)
lg (for laptops and desktops - screens equal to or greater than 1200px wide)
Code Example 6
.col-sm-3half, .col-sm-8half {
position: relative;
min-height: 1px;
padding-right: 15px;
padding-left: 15px;
}
@media (min-width: 768px) {
.col-sm-3half, .col-sm-8half {
float: left;
}
.col-sm-3half {
width: 29.16666667%;
}
.col-sm-8half {
width: 70.83333333%;
}
}
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