:root {
  --bg: #f4f7fb;
  --card: #ffffff;
  --text: #1a2433;
  --accent: #0f8cff;
  --border: #d9e3f2;
  --danger: #b02a2a;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
  background: radial-gradient(circle at 20% 20%, #ebf3ff, var(--bg));
  color: var(--text);
  display: grid;
  place-items: center;
  padding: 20px;
}

.card {
  width: min(720px, 100%);
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  box-shadow: 0 8px 24px rgba(18, 39, 75, 0.08);
  padding: 24px;
}

h1 {
  margin: 0 0 12px;
  font-size: clamp(1.4rem, 3vw, 2rem);
}

h2 {
  margin-top: 0;
  font-size: 1.1rem;
}

p {
  margin: 0 0 12px;
  line-height: 1.45;
}

.panel {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px;
  margin: 16px 0;
  background: #fdfefe;
}

pre {
  margin: 0;
  white-space: pre-wrap;
  word-break: break-word;
  font-size: 0.9rem;
}

.actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  padding: 9px 14px;
}

.btn.ghost {
  background: transparent;
  color: var(--accent);
}

.error {
  color: var(--danger);
  font-weight: 600;
}

.hint {
  color: #526070;
  font-size: 0.9rem;
}