How to move form to center of page - html

Question

I am creating a registration form and am wondering how can I move the whole form to the center of the page? right now its all on the left side of the container, I want it to look a bit something like this: https://id2.s.nfl.com/fans/register?returnTo=http%3A%2F%2Fweeklypickem.fantasy.nfl.com%2F
#Regcontainer {
width: 1200px;
margin: 70px auto;
border: 1px solid;
background-color: aliceblue;
top: 0;
}
.Regcontainer h1 {
font-size: 40px;
font-family: 'Helvetica Neue', sans-serif;
color: black;
line-height: 1;
padding-left: 35px;
padding-top: 35px;
color: black;
}
input {
display: inline-block;
margin: 10px;
}
input[type=text] {
padding: 10px;
border: 2px solid #212;
border-radius: 2px;
box-shadow: #212121;
}
input[type=password] {
padding: 10px;
border: 2px solid #212;
border-radius: 2px;
padding: 5px 10px 5px 10px;
}
input[type=submit] {
background-color: #ff0000;
border: 1px solid #212121;
border-radius: 5px;
color: aliceblue;
font-weight: bold;
}
#back_form {
justify-content: center;
}
<div id="Registercontainer">
<div class="RegForm">
<h1> </h1>
<div id="back_glob">
<div id="back_form">
<form method="POST">
<label>FIRST NAME</label>
<input type="text" name="FName" />
<label>LAST NAME</label>
<input type="text" name="SNAME" />
<br/>
<label>EMAIL ADDRESS</label> <input id="email" name="email" type="text" />
<BR/>
<label>CREATE YOUR USERNAME</label> <input name="uname" type="text" /> <br/>
<label>CREATE PASSWORD</label> <input name="pass" type="password" />
<br/>
<input type="submit" name="valid" value="REGISTER" />
</form>
</div>
</div>
</div>

Answer 1

Here is the solution I came up with... but what does it do?
#Registercontainer needs to be on the center of the page. Meaning, your fixed with of 1200px is not going to work too well. I took the approach of reducing the size of your from container to give a better look and feel like this:
#Registercontainer {
max-width: 600px;
min-width: 320px;
width: 100%;
/* ... your other properties here ... */
}
Another note, your <label> needs the for attribute as specified in this article.
Let me know if you have any questions, FYI there are many ways to make this work for you.
#Registercontainer {
max-width: 600px;
min-width: 320px;
width: 100%;
margin: 70px auto;
border: 1px solid;
background-color: aliceblue;
top: 0;
padding: 15px;
}
.Regcontainer h1 {
font-size: 40px;
font-family: 'Helvetica Neue', sans-serif;
color: black;
line-height: 1;
padding-left: 35px;
padding-top: 35px;
color: black;
}
input {
display: inline-block;
margin: 10px;
}
input[type=text] {
padding: 10px;
border: 2px solid #212;
border-radius: 2px;
box-shadow: #212121;
}
input[type=password] {
padding: 10px;
border: 2px solid #212;
border-radius: 2px;
padding: 5px 10px 5px 10px;
}
input[type=submit] {
background-color: #ff0000;
border: 1px solid #212121;
border-radius: 5px;
color: aliceblue;
font-weight: bold;
}
#back_form {
justify-content: center;
}
<div id="Registercontainer">
<div class="RegForm">
<h1> Register With NackStack</h1>
<div id="back_glob">
<div id="back_form">
<form method="POST">
<label for="fname">FIRST NAME</label>
<input type="text" name="FName" id="fname" />
<br/>
<label for="sname">LAST NAME</label>
<input type="text" name="SNAME" id="sname" />
<br/>
<label for="email">EMAIL ADDRESS</label>
<input id="email" name="email" type="text" />
<br/>
<label for="uname">CREATE YOUR USERNAME</label>
<input name="uname" type="text" id="uname" />
<br/>
<label for="password">CREATE PASSWORD</label>
<input name="pass" type="password" id="password"/>
<br/>
<input type="submit" name="valid" value="REGISTER" />
</form>
</div>
</div>
</div>

Answer 2

Add margin:auto and a fixed width to the parent <div>. Example:
<div id="Registercontainer" style="margin-left:auto;margin-right:auto;width:250px">
Fiddle:
https://jsfiddle.net/mwatz122/g9ay26x3/

Answer 3

#Registercontainer {
text-align: center;
}
Please try this. It might help.

Answer 4

Put your form within a <div> like this:
<div align="center">
<!-- insert code here -->
</div>
Then in the CSS, add
form {
text-align: left;
}