Margin auto is not centering [duplicate] - html

Question

This question already has answers here:
How do I center floated elements?
(12 answers)
How can I horizontally center an element?
(133 answers)
How can I vertically center a div element for all browsers using CSS?
(48 answers)
Flexbox: center horizontally and vertically
(14 answers)
Closed 2 years ago.
I'm just wondering why margin auto isn't working? my parent div margin auto works but my inner margin auto is not in center.
.rankings_page{
width: 750px;
background-color: #f5f5f5;
margin: auto;
height: 800px;
}
.tab-group {
margin: auto;
}
.toggle_btn{
background-color: blue;
float: left;
width: 30%;
text-align: center;
cursor:pointer;
}
<div className="rankings_page">
<div className="tabgroup">
<div className="toggle_btn">
Country
</div>
<div className="toggle_btn">
City
</div>
</div>
</div>
</div>
Thanks!

Answer 1

The margin: auto trick only works if you want to horizontally center your elements. It will not work to vertically center your elements, because of how CSS deals with vertical margins differently.
You should use CSS flexbox instead: it is specifically made to allow layouts like this possible:
display: flex;
align-items: center;
justify-content: center;
Also, you need to update the tabgroup selector, because there is no - in the class in your markup. See proof-of-concept example:
.rankings_page {
width: 750px;
background-color: #f5f5f5;
height: 800px;
display: flex;
align-items: center;
justify-content: center;
}
.tabgroup {
display: flex;
}
.toggle_btn {
background-color: blue;
cursor: pointer;
}
<div class="rankings_page">
<div class="tabgroup">
<div class="toggle_btn">
Country
</div>
<div class="toggle_btn">
City
</div>
</div>
</div>