body {
    margin: 0;
    padding: 0;
    background: #19191A;
    color: #FFFFFF;
}
header {
  text-align: center;
  padding: 20px;
}

#logo {
  float: left;
  height: 180px;
  margin-right: 20px;
}

nav a {
  margin: 0 10px;
  color: white;
  text-decoration: none;
}

main {
  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
}

.btn {
  background-color: red;
  color: white;
  padding: 10px 20px;
  text-decoration: none;
  border-radius: 5px;
  display: inline-block;
  margin-top: 10px;
}

.instructor {
  text-align: center;
  margin-bottom: 20px;
}

.instructor img {
  display: block;
  margin: 0 auto 10px;
  border-radius: 8px;
  max-width: 100%;
  height: auto;
}

@media (max-width: 600px) {
  .instructor img {
    width: 100%;
    max-width: 240px;
  }
}

footer {
  text-align: center;
  padding: 10px;
}
/* Instructor page formatting */
#instructor-details {
    max-width: 900px;
    margin: 0 auto;
    line-height: 1.8;
}

.bio {
    text-indent: 2em;
    margin-bottom: 20px;
}

#instructor-details img {
    float: right;
    margin-left: 30px;
    margin-bottom: 20px;
    border-radius: 8px;
}

#instructor-details h3 {
    margin-top: 30px;
}