I apologize in advanced because I know this is a very basic, newbie mistake - but no matter what I add to this, my main container will not center in the page. I know there's plenty of ways to achieve this goal, but ultimately I'm trying to practice 'good coding' habits, and making this efficient as possible ( as opposed to many margins and paddings ). The goal is to eventually have it look like this:
Here's my code ( so far ):
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="initial-scale=1.0, width=device-width"/>
<!-- BROWSER TITLE -->
<title>cookiess</title>
<!-- END OF BROWSER TITLE -->
<!-- BROWSER ICON -->
<link rel="shortcut icon" href="https://66.media.tumblr.com/e948812964cb16505f4cd4f894344288/672e88b582120b94-84/s540x810/9301ad0a7a1dc0235256ca2aa89738258b0383a5.png">
<!-- END OF BROWSER ICON -->
<!-- FONTS -->
<link href="https://fonts.googleapis.com/css2?family=Bowlby+One&display=swap" rel="stylesheet">
<link href='https://fonts.googleapis.com/css?family=Roboto:400,400italic,900,700,700italic,500italic,500' rel='stylesheet' type='text/css'>
<!-- END OF FONTS -->
<!-- SMOOTH SCROLL SCRIPT -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/smoothscroll/1.4.1/SmoothScroll.min.js"></script>
<!-- END OF SMOOTH SCROLL SCRIPT -->
<!-- SCROLL TO TOP BUTTON -->
<button onclick="topFunction()" id="stt" title="Go to top">Top</button>
<!-- END OF SCROLL TO TOP BUTTON -->
<style type="text/css">
body { background-color:#e6eaeb;
color:#e6eaeb;
font-family:'Roboto', sans-serif;
font-size:10px;
text-align:left;
word-spacing:3px;
text-transform:uppercase; }
/* SELECTION */
::selection { background:#ff40f3; }
::-moz-selection { background:#ff40f3; }
/* END OF SELECTION */
/* SCROLLBAR */
::-webkit-scrollbar-thumb { background:#ff62f5;
border-radius:25px;linear-gradient(to bottom, #b1e0f5 , #ffc4f6);
width:8px;
height:5px; }
::-webkit-scrollbar { background:#292929;
border-radius:25px;
height:5px;
width:8px; }
/* END OF SCROLLBAR */
/* SCROLL TO TOP BUTTON */
#stt { position: fixed; /* Fixed/sticky position */
z-index:99999999999999;
display: none; /* Hidden by default */
top:613px; /* Place the button at the bottom of the page */
left:1029px; /* Place the button 30px from the right */
border: none; /* Remove borders */
outline: none; /* Remove outline */
font-family:'Bowlby One', cursive;
background-color: #02afff; /* Set a background color */
color:#e6eaeb;
cursor: pointer; /* Add a mouse pointer on hover */
padding:8px;
border-radius: 15px; /* Rounded corners */
text-transform:uppercase;
text-align:center;
font-size: 9px; /* Increase font size */ }
/* END OF SCROLL TO TOP BUTTON */
.maincontainer { background-color:#313131;
width:785px;
height:472px;
color:#313131;
border-top:25px solid #02afff;
border-bottom:25px solid #02afff;
margin:auto;
-webkit-box-shadow: 0px 5px 10px 1px rgba(0,0,0,0.39);
-moz-box-shadow: 0px 5px 10px 1px rgba(0,0,0,0.39);
box-shadow: 0px 5px 10px 1px rgba(0,0,0,0.39); }
#wave { position:fixed;
z-index:-100;
width:100%;
bottom:-3px;
background-repeat:repeat-x;
left: 0px;
right: 0px; }
</style>
</head>
<body>
<div id="wave">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1440 320">
<path fill="#ffa6f9" fill-opacity="1" d="M0,192L34.3,176C68.6,160,137,128,206,149.3C274.3,171,343,245,411,256C480,267,549,213,617,192C685.7,171,754,181,823,186.7C891.4,192,960,192,1029,202.7C1097.1,213,1166,235,1234,240C1302.9,245,1371,235,1406,229.3L1440,224L1440,320L1405.7,320C1371.4,320,1303,320,1234,320C1165.7,320,1097,320,1029,320C960,320,891,320,823,320C754.3,320,686,320,617,320C548.6,320,480,320,411,320C342.9,320,274,320,206,320C137.1,320,69,320,34,320L0,320Z"></path>
</svg>
</div>
<div class="maincontainer">Hi there!</div>
</body>
</html>