I changed the font-weight to bold but it says that its not


#1

me too.

<!DOCTYPE html>
<html>
  <head>
    <link href="main.css" rel="stylesheet">
  </head>
  
  <body>
    <div class= .nav a {
    color: #5a5a5a;
    font-size: 11px;
    font-weight: bold;
    padding-top: 14px;
    padding-bottom: 14px;
    padding-left:  10px;
    text-transform: uppercase;
    } 
      <div class="container">
        <ul>
          <li><a href="#">Airbnb logo</a></li>
          <li><a href="#">Browse</a></li>
          <li><a href="#">Sign Up</a></li>
          <li><a href="#">Log In</a></li>
          <li><a href="#">Help</a></li>
        </ul>
      </div>
    </div>

    <div class="jumbotron">

I changed the font-weight to bold but it says that its not
#2

This is supposed to be under css tab

When selecting an element in css if it's a class you put .classname

So take out div class= and just leave .nav a