body {
  font-family: Arial, sans-serif;
  background: #f8f9fa;
  margin: 0;
  padding: 0;
  color: #222;
}

header.nav {
  background: #111;
  color: #fff;
  padding: 15px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand { font-size: 20px; font-weight: bold; }
.brand span { color: #0f0; }

.btn {
  background: #0f62fe;
  color: #fff;
  padding: 8px 14px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  text-decoration: none;
}

main.shell {
  max-width: 600px;
  margin: 40px auto;
  padding: 20px;
}

.card {
  background: #fff;
  padding: 20px;
  border-radius: 12px;
  margin-bottom: 20px;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

input#m {
  width: 80%;
  padding: 10px;
  border: 1px solid #ccc;
  border-radius: 6px;
}

pre.response {
  background: #f1f1f1;
  padding: 15px;
  border-radius: 6px;
  margin-top: 15px;
  white-space: pre-wrap;
}