* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Helvetica Neue", Arial, sans-serif;
  background: linear-gradient(135deg, #f8fafc, #e2e8f0);
  color: #0f172a;
}

.container {
  max-width: 720px;
  margin: 8vh auto;
  padding: 2rem;
  background: #ffffff;
  border-radius: 16px;
  box-shadow: 0 10px 25px rgba(15, 23, 42, 0.08);
}

h1,
h2 {
  margin-top: 0;
}

.panel {
  margin-top: 1.25rem;
  padding: 1rem;
  border: 1px solid #e2e8f0;
  border-radius: 12px;
  background: #f8fafc;
}

button {
  border: none;
  border-radius: 8px;
  padding: 0.6rem 0.9rem;
  background: #0f172a;
  color: #ffffff;
  cursor: pointer;
}

button:hover {
  opacity: 0.9;
}