My form "submit" buttons are all left-aligned

Site URL: http://www.scienceisWEIRD.com/write-us

None of the "submit" buttons in my forms will center justify... even when I tell them to!

(They also won't right justify, or whatever. They're all left justified.)

Perhaps the problem is some custom code I put in a year ago. Here 'tis:

/* BLUE form button color */
.sqs-block.form-block
.form-wrapper input[type="submit"] {
  display: block;
  background: #0BA2FE;
  color: white;
  border:none;
  font-size: 22px !important;
  font-weight: 400;

    border-radius: 2px
    cursor: pointer;
}

And even if that's not the problem, maybe there's a line I can add in there that will fix the problem?

Any/every idea would be appreciated!

To center button, use this CSS

input.button.sqs-system-button.sqs-editable-button.sqs-button-element--primary {
    margin: 0 auto;
}