:root {
  --bg: #f4f7fb;
  --card: #ffffff;
  --text: #112033;
  --muted: #5f6b7a;
  --primary: #1f6feb;
  --border: #d7e0ea;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: linear-gradient(140deg, #eef5ff 0%, var(--bg) 60%, #f7fbff 100%);
  color: var(--text);
  display: grid;
  place-items: center;
  padding: 24px;
}

.card {
  width: min(860px, 95vw);
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 28px;
  box-shadow: 0 10px 30px rgba(17, 32, 51, 0.08);
}

h1,h2,h3 { margin: 0 0 12px; }
p { margin: 8px 0; }
ul { margin: 8px 0 0 20px; }

.muted { color: var(--muted); }

.btn {
  display: inline-block;
  margin-top: 10px;
  padding: 11px 16px;
  background: var(--primary);
  color: #fff;
  border: 0;
  border-radius: 10px;
  text-decoration: none;
  font-weight: 600;
  cursor: pointer;
}

.btn.secondary {
  background: #e8effa;
  color: #0f3d7a;
}

.error {
  margin-bottom: 10px;
  border: 1px solid #f3b0b0;
  background: #ffecec;
  color: #842029;
  border-radius: 10px;
  padding: 10px 12px;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 14px;
  margin: 10px 0 14px;
}

pre {
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #f8fbff;
  max-height: 340px;
  overflow: auto;
}