Why is margin not working for <p> element? - html

Question

I want to specify margins for all p elements in my html/php page. It should be straightforward, but it doesn't work for me. Please excuse my noob level.
Here is my css code I added to the head:
<style>
p {
margin-left: 120px;
margin-right: 120px;
}
.code {
color : blue;
background-color: lightgrey
}
.center {
text-align: center;
}
</style>
In the body I have p elements, none of which has a margin.In body Example:
<a name="hardware"></a>
<h4>Required hardware:</h4>
<p>
I tested this procedure on a Raspberry Pi 3B+, having 1 GB of RAM.
</p>
Does anyone know why the left/right margin is not working?

Answer 1

I see that margins added.
Maybe because of added class center to p you don't see. If you provide us with more code, it will be clearer.
To illustrate the idea I made snippet, look inti it.
P.S. useful to know, margin in css between siblings not added but the bigger margin wins. You can see in snippet, that p has default top and bottom margin, but sibling ps have gap between them which equals to one of margin's value, not margin-bottom + marging-top values.
.margins {
margin-left: 120px;
margin-right: 120px;
}
.center {
text-align: center;
}
.p-border p {
border: 1px solid black;
}
.border-dot {
border: 1px dotted black;
}
<div class="border-dot">
<p class="center margins">With margins</p>
<p class="center margins">With margins</p>
<p class="center">Without margins</p>
</div>
<div class="border-dot p-border">
<p class="center margins">With margins</p>
<p class="center margins">With margins</p>
<p class="center">Without margins</p>
</div>