:root {
  --bg: #f8fafc;
  --panel: #ffffff;
  --text: #1e293b;
  --muted: #64748b;
  --line: #e2e8f0;
  --ink: #0f172a;
  --accent: #0b57d0;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  background: linear-gradient(180deg, #f8fafc 0%, #f1f5f9 100%);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

.shell {
  max-width: 920px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid var(--line);
  background: rgba(248, 250, 252, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.topbar-inner {
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.topbar a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 600;
}

.topbar a:hover {
  color: var(--ink);
}

.card {
  margin: 2rem auto 3rem;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: 0 12px 32px rgba(15, 23, 42, 0.06);
  padding: 1.6rem;
}

h1 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(1.8rem, 2.7vw, 2.4rem);
  letter-spacing: -0.02em;
}

h2 {
  margin: 1.4rem 0 0.55rem;
  color: var(--ink);
  font-size: 1.08rem;
}

p,
li {
  color: var(--text);
  line-height: 1.65;
  font-size: 0.96rem;
}

.muted {
  margin-top: 0.5rem;
  color: var(--muted);
  font-size: 0.86rem;
}

ul {
  margin: 0.5rem 0 0.8rem;
  padding-left: 1.2rem;
}

a.inline {
  color: var(--accent);
  text-decoration: none;
}

a.inline:hover {
  text-decoration: underline;
}

.footer-note {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.86rem;
}