/* UPE–Riemann (Giant) — Classic minimal 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: 1.9rem; }

nav {
  display: flex;
  gap: 1rem;
  padding: 0.6rem 1rem;
  background: var(--light);
  border-bottom: 1px solid #c2d4ea;
}
nav a {
  color: #0a2540;
  text-decoration: none;
  font-weight: 600;
}

main {
  max-width: 760px;
  margin: 1.5rem auto;
  padding: 0 1rem;
}

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

.card {
  border: 1px solid #cfd8e3;
  padding: 1rem;
  border-radius: 10px;
  background: #fff;
  margin-top: 1rem;
  box-shadow: 0 2px 6px rgba(0,0,0,.04);
}

input[type="text"] {
  width: 100%;
  max-width: 520px;
  padding: 0.6rem;
  font-size: 1rem;
  margin-right: 0.5rem;
  border: 1px solid #cfd8e3;
  border-radius: 6px;
}

button, .btn {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 0.6rem 1rem;
  font-size: 1rem;
  border-radius: 6px;
  cursor: pointer;
  text-decoration: none;
}
button:hover, .btn:hover { background: #163a5c; }

#output {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  line-height: 1.5;
}

.note {
  color: #444;
  font-size: 0.95rem;
  margin-top: 0.5rem;
}
footer {
  margin-top: 2rem; padding: 1rem; text-align: center;
  border-top: 1px solid #e5e7eb; color: #555; font-size: 0.9rem;
}