I put a div around each button and I set them both to inline. They just want to stack as I keep trying to center them.
This is my HTML:
     body{
  background-color:black;
     }
    #light{
 margin-left:50%;
 margin-right:70%;
    }
    #dark{
 margin-left:50%;
 margin-right:50%;
 display:inline-block;
    }
 
    h3{
 color:white;
 font-family:Courier New;
 font-size:24px;
 margin-left:500px;
    }    <!DOCTYPE html>
    <html>
    <head>
    <title>question reality.</title>
    <link rel="stylesheet" type="text/css" href="intro page.css">
    </head>
    <body>
    <h3>make your choice.</h3>
    <div id="light"><button>Light</button></div>
    <div id="dark"><button>Dark</button></div>
    </body>
    </html>This is a screencap of what this thing is doing:

 
     
     
     
     
     
    