body {
  margin: 0;
  font-family: Arial, sans-serif;
}

.main-nav {
  width: 200px;
  background: linear-gradient(#3F7177, #2f5a5f);
}

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

.main-nav li {
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.main-nav a {
  display: block;
  padding: 12px 16px;
  color: white;
  text-decoration: none;
  transition: background 0.3s, padding-left 0.2s;
}

.main-nav a:hover {
  background-color: #5f9ea0;
  padding-left: 20px;
}