style.css

body {
  position: relative;
  margin: 0;
  padding: 0;
  font-family: sans-serif;
  font-size: 16px;
}
.container {
  width: 80%;
  margin: 0 auto;
}
.nav-bar {
  position: fixed;
  top: 0;
  margin: 0 0 0 -10%;
  width: 100%;
  z-index: 2;
  text-align: center;
  line-height: 35px;
  border-bottom: 1px solid #bbb;
  box-shadow: 2px 0 2px 0 rgba(0, 0, 0, 0.5);
}
.nav-bar ul.nav {
  display: inline-block;
  list-style: none;
  padding: 0;
  margin: 0;
}
.nav-bar li {
  display: inline-block;
}
.nav-bar a {
  color: darkgray;
  text-decoration: none;
}
.nav-bar a:hover {
  color: lightgray;
}
.btn {
  padding: 8px;
  font-family: inherit;
  font-size: inherit;
  border-radius: 3px;
  border: 1px;
  cursor: pointer;
}
.btn-section {
  background-color: transparent;
}
.btn-section:hover {
  background-color: #eee;
}
.btn-user {
  background-color: lightgray;
}
.btn-user:hover {
  background-color: darkgray;
  color: white;
}
.left {
  float: left;
}
.right {
  float: right;
}