<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>calc</title>
</head>
<body>
  <header>
    FAKEBOOK.COM
  </header>
  <nav>
    <ul style="list-style: none;">
      <li>HOME</li>
      <li>CHAT</li>
      <li>FRIENDS</li>
      <li>NETWORK</li>
      <li>COMMUNITY</li>
      <li>Q&amp;A</li>
    </ul>  
  </nav>
  <main>
    <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Sint ut, eveniet dolores nostrum quo fugiat fugit eos sapiente, ex eius saepe sit aliquam. Ipsam quisquam quaerat praesentium, ipsum accusamus magni?</p>
        <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Sint ut, eveniet dolores nostrum quo fugiat fugit eos sapiente, ex eius saepe sit aliquam. Ipsam quisquam quaerat praesentium, ipsum accusamus magni?</p>
        <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Sint ut, eveniet dolores nostrum quo fugiat fugit eos sapiente, ex eius saepe sit aliquam. Ipsam quisquam quaerat praesentium, ipsum accusamus magni?</p>
  </main>
</body>
</html>
:root {
  --font-size : 1.5vw;
}

header { 
  background-color:blue;
  color:white;
  font-size: calc(var(--font-size) * 2.5);
  width: calc(100vw * (30/100));
  margin: 0 auto;
  text-align:center;
}

nav {
  margin-top:1rem;  
}

ul {
  display:flex;
  width: calc(100% - 20%);
  height:calc(var(--font-size) * 2);
  display:flex;
  align-items:center;
  margin:0 auto;
  justify-content:space-between;
  background-color:blue;
  padding-inline-start: unset;
  padding:0 50px;
  color:white;
}

ul > li:active {
  background-color:skyblue;
}

main {
  width: calc(100% - 200px);
  margin:0 auto;  
  margin-top:2rem;
  font-size: 1.2rem;
}

main > p::first-letter {
   font-weight:bold;
   font-size:2rem;
}

main > p::selection {
  background-color:yellow;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.