Cheat Sheet Project (work in progress)

Hi Guys, I just finished the CSS section on the Web Development Path, and I am building my own cheatsheet with what I have learned so far,

Here is my link to Github as well

HTML Code:

Learning HTML & CSS
<body>
	
	<header class="header">
		<h1>Learning HTML and CSS</h1>
		<p>Welcome to the cheatsheet for HTML and CSS, this page is dedicated for usefull information and a guide if you need to refresh your memory on anything HTML or CSS.</p>
	</header>
	<hr>
	<h2>HTML</h2>
		<h3>1. Main skeleton of html</h3>
			<p>This section will show the basic skeleton you need for creating html</p>

	<!-- Makes the sample suqare-->
	<div>
		<div class="sample-box ">
			<p>&lt;!DOCTYPE html&gt;</p>
			<pre>   &lt;html&gt;</pre>
			<pre>      &lt;head&gt;</pre>
			<pre>         &lt;title&gt;<em style="color: white">title of webpage</em>&lt;/title&gt;</pre>
			<pre>      &lt;/head&gt;</pre>
			<pre>      &lt;body&gt;</pre>
			<pre>      &lt;/body&gt;</pre>
			<pre>   &lt;/html&gt;</pre>
		</div>
		<br>
	
		<div>
			<table>
				<thead>
					<th>Tag</th>
					<th>Name</th>
					<th>Description</th>
				</thead>	
				<tbody>
					<tr>
						<td class="tag">&lt;!DOCTYPE html&gt;</td>
						<td>HTML declaration</td>
						<td>Tells the browser that the code is in HTML</td>
					</tr>
					<tr>
						<td class="tag">&lt;html&gt; &lt;/html&gt;</td>
						<td>HTML tags</td>
						<td>All the HTML code needs to be in between these two tags</td>
					</tr>
					<tr>
						<td class="tag">&lt;head&gt; &lt;/head&gt;</td>
						<td>heading of website</td>
						<td>Main title of the website. Also, appears on the tab</td>
					</tr>
					<tr>
						<td class="tag">&lt;title&gt; &lt;/title&gt;</td>
						<td>Title information of the page</td>
						<td>Use for the title of the page, also shows what is display on your tab</td>
					</tr>
					<tr>
						<td class="tag">&lt;body&gt; &lt;/body&gt;</td>
						<td>Main body of the page</td>
						<td>Containts all the content of the webpage</td>
					</tr>
				</tbody>
			</table>
		</div>
		<div class="image-box">
			<img src="htmlpic.png" alt="html pick">
		</div>	
	</div>
</main>

<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<hr>


</body>

CSS Code:
html{
background-color: #1D2731;
color:white ;
}

header {
text-align: center;
}

h1, h2, h3 {
color: #D9B310;
}

.sample-box {
width: 300px;
height: 260px;
background-color: #0B3C5D;
font-weight: bold;
font-family: monospace;
color: #328CC1;
float: left;
margin: 25px;
margin-top: 20px;
}

table {
width: 800px;
height: 265px;
float: left;
margin-bottom: 30px;
background-color: #0B3C5D;
padding: 5px;
}

tr, td {
border: 1px solid white;
}

th {
border: 1px solid white;
color: #D9B310;
}

.tag {
color: #D9B310;
font-weight: bold;
}

.image-box {
float: left;
background-color: #0B3C5D;
width: 300px;
height: 265px;
margin: 25px;
margin-top: 1px;
}

img {
margin-top: 10px;
width: 280px;
height: 245px;
margin-left: 10px;
}


I am still planning on adding a lot more stuff to it, I just wanted to get some advice on anything I might be doing wrong and that I can do better.

Thanks in advance