* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

header {
  background: #333;
  color: #fff;
  padding: 20px;
  text-align: center;
}

nav ul {
  list-style: none;
  padding: 0;
}

nav ul li {
  display: inline;
  margin-right: 10px;
}

nav ul li a {
  color: #fff;
  text-decoration: none;
}

.intro {
  text-align: center;
  padding: 40px;
  background: #f4f4f4;
}

.features {
  display: flex;
  justify-content: space-around;
  padding: 20px;
}

.feature-item {
  background: #fff;
  padding: 20px;
  border: 1px solid #ddd;
  width: 30%;
}

footer {
  text-align: center;
  padding: 20px;
  background: #333;
  color: #fff;
}