body {
  font-family: Helvetica;
  font-size: 22px;
  color: seashell;
  background-color: black;
  text-align: center;
  margin: 0;
  opacity: 0.9;
}

header {
  height: 69px;
  width: 100%;
  border-bottom: 1px solid seashell;
  position: sticky;
  top: 0px;
  display: block;
  background-color: black;
}

.child-1 {
    padding-left: 10px;
    padding-top: 9.5px;
    float: left;
    height: 50px;
    top: 70px;
}

ul{
  float: right;
  margin: 0 auto;
  height: 100%
}
  
a {
  height: 100%;
  display: table;
  float: left;
  padding: 0px 20px;
}

li {
  list-style-type: none;
  display: table-cell;
  vertical-align: middle;
  height: 100%;
  text-decoration: underline;
  color: seashell;
}

.container-2 {
  background-image: url("https://s3.amazonaws.com/codecademy-content/courses/freelance-1/unit-4/img-mission-background.jpg");
  background-repeat: no-repeat;
  background-position: center;
  max-width: 1200px;
  height: 700px;
  margin: 40px auto;
  display: flex;
}

.child-2 {
  margin: auto;
  background-color: black;
  width: 100%;
}

.container-3 {
  max-width: 1000px;
  height: auto;
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
}

.child-3 img{
  padding: 10px;
  width: 300px;
  height: 200px;
}

.container-4 {
  height: 500px;
  max-width: 1200px;
  margin: 40px auto auto auto;
  padding-top: 85px;
  background-image: url("https://s3.amazonaws.com/codecademy-content/courses/freelance-1/unit-4/img-locations-background.jpg");
  background-repeat: no-repeat;
  background-position: center;
  background-size: cover;
}

.container-4a {
  max-width: 1050px;
  margin-top: 15px;
  margin-left: 50px;
  display: flex;
  justify-content: space-between;
}

.child-4a {
  background-color: black;
  height: 300px;
  padding: 20px;
  margin-bottom: auto;
  flex-basis: 30%;
  box-sizing: border-box;
  opacity: 1;
}

footer {
  text-align: left;
  margin: 20px;
}