CSS isn't styling my navigation bar

Using the code below, I am trying to design a nav bar header. I made a bar class, and I applied it to a div, then added some text and buttons. I tried to make it purple and give it some padding, but I get none of that. What am I doing wrong?

        <div class="row bar container-fluid">
          <div class="col-md-4">
            <h3>CAEMS Girls Who Code</h3>
          </div>
          <div class="col-md-5">
          </div>
          <div class="col-md-1">
            <button class="btn">about</button>
          </div>
          <div class="col-md-1">
            <button class="btn">works</button>
          </div>
          <div class="col-md-1">
            <button class="btn">contact</button>
          </div>
          </div>

    #bar {
      background-color: rgb(153, 0, 153);
      height: 50px;
      padding: 15px;
      border: 2px;
    }

Wow. Thanks. I should probably write that down somewhere.
:confounded: