body {
  font-family: Arial, sans-serif;
  background: #f4f4f4;
  margin: 0;
}
header, nav, footer {
  background: #fff;
  padding: 1rem;
  text-align: center;
}
nav a {
  margin: 0 1rem;
  text-decoration: none;
  color: #333;
}
.container {
  max-width: 600px;
  margin: 2rem auto;
  padding: 1rem;
  background: white;
  border-radius: 8px;
}
.ad-placeholder {
  background: #ddd;
  text-align: center;
  padding: 1rem;
  margin: 1rem 0;
}
input {
  width: 100%;
  padding: 0.5rem;
  margin: 0.5rem 0 1rem 0;
}
.back-home {
  display: inline-block;
  margin-top: 2rem;
  background: #1e88e5;
  color: white;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  text-decoration: none;
}