Unfortunately, your question is too large to provide a concise answer here. However, I recommend looking into media queries. You can check out this informative video on YouTube to grasp the basics quickly:
https://www.youtube.com/watch?v=fA1NW-T1QXc
In the HTML head section:
<meta name="viewport" content="width=device-width, initial-scale=1">
In the HTML body section:
<div id="container"><div id="header">Logo</div></div>
CSS Styles:
#container{width: 1000px; height: 500px;}
#header{width: 1000px; height: 100px; text-align: center;}
@media only screen and (max-width: 999px){#container{width:100%;}#header{width: 100%;background-color: blue;}}
This example demonstrates that when the screen width is below 999px, the header will turn blue and adjust to fit within the screen size.