body {
  font-family: Arial, sans-serif;
  line-height: 1.6;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: #000;
  color: #fff;
  padding: 8px;
  z-index: 100;
}

.skip-link:focus {
  top: 0;
}

header {
  background: #333;
  color: #fff;
  padding: 1rem;
  text-align: center;
}

nav ul {
 body {
  font-family: Arial, sans-serif;
  line-height: 1.6;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: #000;
  color: #fff;
  padding: 8px;
  z-index: 100;
}

.skip-link:focus {
  top: 0;
}

header {
  background: #333;
  color: #fff;
  padding: 1rem;
  text-align: center;
}

nav ul {
display: flex;
justify-content: center;
list-style: none;
padding: 0;
}
nav ul li {
margin-right: 1rem;
}
nav ul li:last-child {
margin-right: 0;
}
nav a {
color: #333;
text-decoration: none;
}
nav a:focus {
background-color: #ddd;
}
#toggleDarkMode {
background-color: #333;
border: none;
color: #fff;
cursor: pointer;
margin-left: 1rem;
padding: 5px 10px;
}
.dark-mode {
background-color: #222;
color: #ddd;
}
.dark-mode header {
background-color: #555;
}
.dark-mode nav a {
color: #ddd;
}
.dark-mode nav a:focus {
background-color: #444;
}
.dark-mode #toggleDarkMode {
background-color: #555;
}
.sr-only {
position: absolute;
width: 1px;
height: 1px;
padding: 0;
margin: -1px;
overflow: hidden;
clip: rect(0, 0, 0, 0);
border: 0;
}