How do I center a container

I’m trying to center a container using the code shown below. I’ve tried various way in both html and css without success. The related css follows:

“`

<style>
.container {
display: flex;
max-width: 1800px;
margin-right: auto;
margin-left: auto;
padding-top: .3rem;
padding-bottom: 1.5rem;
}

.divL, .divR {
box-sizing: border-box;
padding: 5px;
border: solid 1px #000000;
}

.divL {
background: #eaeaea;
width: 50% ;
}
.divR {
background: #eaeaea;
width: 50% ;
}

.divR h1 {
font-size:24px;
font-weight:bold;
margin-bottom:8px;
border-bottom:solid 1px #000000;
padding-bottom:10px;
text-align: center;
}
.divR h2 {
font-size:18px;
font-weight:bold;
margin-bottom:4px;
padding-bottom:5px;
text-align: center;
}
.divR h4 {
font-size:16px;
font-weight:normal;
margin-bottom:4px;
padding-bottom:5px;
text-align:left;
}
.divL h1 {
font-size:24px;
font-weight:bold;
margin-bottom:8px;
border-bottom:solid 1px #000000;
padding-bottom:10px;
text-align: center;
}
.divL h2 {
font-size:18px;
font-weight:bold;
margin-bottom:4px;
padding-bottom:5px;
text-align: center;
}
.divL h4 {
font-size:16px;
font-weight:normal;
margin-bottom:4px;
padding-bottom:5px;
text-align: left;
}
.p {
font-size:16px;
color:#000000;
font-weight:normal;
margin-bottom:8px;
padding-bottom:10px;
}
.h1 {
font-size:24px;
font-weight:bold;
margin-bottom:4px;
border-bottom:solid 3px #000000;
padding-bottom:5px;
text-align: center;
}

</style>
“`

The html follows:

“`
<div class=”download”>
<br /><br>
<h1><center>FoxClone Download Page</center></h1>
<div class=”container”>
<div class=”divL”>
<h3>Get the “<?php echo “{$filename}”;?>” file (approx. 600MB)</h3>
<center> <a href=”<?php echo “/{$file}”;?>”><img src=”images/button_get-the-app.png” alt=””></a> </center><br />
<h3 style=”margin-bottom: 0.5rem;”>The MD5sum for “<?php echo “{$filename}”;?>” is “<?php echo “{$md5file}”;?> <br />
_______________________________________________________________”</h3>
<h3>Read or Download the Installation and Use Instructions </h3>
<center> <a href=”<?php echo “/{$pdf}”;?>”><img src=”images/button_read-the-file.png” alt=””></a></center><br /><h3>
_______________________________________________________________”</h3>

<h3>How To Install To A USB/CD</h3>
<h4>1. Download the iso file <br />
2.&nbspa. If burning to a USB stick use the USB image writer that comes with your distribution. <br />
&nbsp&nbsp&nbsp b. If burning to a CD, there are many Linux utilities, xfburn is one of the simplest. Install from your software
manager/centre if not installed.</h4>
<br />
<h3>How To Boot The USB/CD</h3>
<h4>At the manufacturer’s splash screen, press the key to get into the boot menu. This key varies across PCs, as an example for a Lenovo
Thinkpad it is F12. Consult your user manual to find out what the key is or google. Do not confuse the boot menu with the boot priority order
settings in BIOS. The boot menu is a one time selection for the device to use to boot the PC. It overrides the normal boot priority order. The next
time you boot, the PC will revert to the normal boot order. Virtually all BIOSs support this feature, they just do it differently. </h4>
</div>

<div class=”divR”>
<h3>Get the “<?php echo “{$debname}”;?>” file (approx. 7MB) </h3>
<center> <a href=”<?php echo “/{$deb}”;?>”><img src=”images/button_download.png” alt=””></a></center><br />

<h3 style=”color:red”><b>WARNING – DO NOT INSTALL THIS TO YOUR COMPUTER !!!</b></h3>
<h4 style=”color:black”>This .deb file is designed to be installed on a large USB drive, typically 1TB or greater, that already has an operating system installed and is intended as a backup drive.</h4>

<h4><b>For more information <a href=’download/deb_file.pdf’ style=’color:#ff0099;’>Click Here</a></b></h4><br><h3>
______________________________________________________</h3>

<h3>Get the “<?php echo “{$srcname}”;?>” Source file (approx. 6MB) </h3>
<center> <a href=”<?php echo “/{$src}”;?>”><img src=”images/button_download.png” alt=””></a></center>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
“`

Also in #CSS _↴