body {
  font-family: Arial, sans-serif;
  line-height: 1.6;
  margin: 0;
  padding: 0;
  background-color: #ffffff;
  color: #000000;
}
header {
  background-color: #003366;
  color: white;
  padding: 1em;
  text-align: center;
}
nav {
  background-color: #0055aa;
}
nav ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  margin: 0;
  padding: 0;
}
nav li {
  flex: 1 1 auto;
}
nav a {
  display: block;
  padding: 0.8em;
  color: white;
  text-align: center;
  text-decoration: none;
}
nav a:focus,
nav a:hover {
  background-color: #003366;
  outline: 2px solid yellow;
}
.container {
  padding: 1em;
  max-width: 960px;
  margin: auto;
}
.search-box {
  margin-bottom: 1em;
  display: flex;
}
.search-box input[type="search"] {
  flex: 1;
  padding: 0.5em;
  font-size: 1em;
}
.search-box button {
  padding: 0.5em 1em;
  font-size: 1em;
  background-color: #0055aa;
  color: white;
  border: none;
  cursor: pointer;
}
.search-box button:focus {
  outline: 2px solid yellow;
}
mark {
  background-color: yellow;
  font-weight: bold;
}
footer {
  background-color: #003366;
  color: white;
  text-align: center;
  padding: 1em;
  margin-top: 2em;
}