body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0 1rem;
  background: #f7f7f7;
}
header {
  background: #2d6a4f;
  color: white;
  padding: 1rem;
}
section {
  background: white;
  padding: 1rem;
  margin: 1rem 0;
  border-radius: 8px;
}
input, textarea {
  display: block;
  width: 100%;
  margin: 0.5rem 0;
  padding: 0.5rem;
}
button {
  padding: 0.5rem 1rem;
  margin: 0.25rem 0;
}
.activity {
  border: 1px solid #ccc;
  padding: 0.5rem;
  margin: 0.5rem 0;
  border-radius: 6px;
}