/* UPE–Riemann Calculator Styles */

:root {
  --accent: #1f4e79;
  --light: #d9e2f3;
  --ink: #111;
  --bg: #fff;
}

* {
  box-sizing: border-box;
}

body {
  font-family: system-ui, Arial, sans-serif;
  margin: 0;
  background: var(--bg);
  color: var(--ink);
}

header {
  background: var(--accent);
  color: white;
  padding: 1rem;
  text-align: center;
}

header h1 {
  margin: 0;
  font-size: 1.8rem;
}

main {
  max-width: 600px;
  margin: 2rem auto;
  padding: 1rem;
}

h2 {
  color: var(--accent);
}

input[type="number"] {
  padding: 0.5rem;
  font-size: 1rem;
  width: 70%;
  margin-right: 0.5rem;
}

button {
  background: var(--accent);
  color: white;
  border: none;
  padding: 0.6rem 1rem;
  font-size: 1rem;
  border-radius: 6px;
  cursor: pointer;
}

button:hover {
  background: #163a5c;
}

.card {
  border: 1px solid #ccc;
  padding: 1rem;
  margin-top: 1.5rem;
  border-radius: 8px;
  background: var(--light);
}

#output {
  font-weight: bold;
  font-size: 1.2rem;
}

footer {
  margin-top: 2rem;
  padding: 1rem;
  text-align: center;
  border-top: 1px solid #ccc;
  font-size: 0.9rem;
  color: #555;
}