/* Notion-like reading page: white, one column, system / Inter type. */
:root {
  --text: #191919;
  --muted: #6b6b6b;
  --faint: #9b9a97;
  --line: #ececeb;
  --callout: #f7f6f3;
  --link: #191919;
  --accent: #0a84ff;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: #ffffff;
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", Inter, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}

.topbar-inner {
  max-width: 760px;
  margin: 0 auto;
  padding: 10px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  font-size: 14px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
}

.brand img { width: 22px; height: 22px; border-radius: 6px; }

.nav { display: flex; gap: 4px; flex-wrap: wrap; justify-content: flex-end; }

.nav a {
  color: var(--muted);
  text-decoration: none;
  padding: 4px 8px;
  border-radius: 6px;
}

.nav a:hover { background: var(--callout); color: var(--text); }
.nav a[aria-current="page"] { color: var(--text); font-weight: 500; }

main {
  max-width: 760px;
  margin: 0 auto;
  padding: 56px 24px 96px;
}

h1 {
  font-size: 40px;
  line-height: 1.2;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 12px;
}

.meta {
  display: grid;
  grid-template-columns: 140px 1fr;
  row-gap: 6px;
  font-size: 14px;
  color: var(--muted);
  padding: 12px 0 20px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 28px;
}

.meta dt { color: var(--faint); }
.meta dd { margin: 0; color: var(--text); }

h2 {
  font-size: 24px;
  line-height: 1.3;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 40px 0 8px;
}

h3 {
  font-size: 18px;
  font-weight: 600;
  margin: 24px 0 4px;
}

p { margin: 6px 0 12px; }

ul { margin: 4px 0 14px; padding-left: 22px; }
li { margin: 3px 0; }
li::marker { color: var(--faint); }

a { color: var(--link); text-decoration: underline; text-decoration-color: #c9c8c4; text-underline-offset: 3px; }
a:hover { text-decoration-color: var(--text); }

.callout {
  display: flex;
  gap: 12px;
  background: var(--callout);
  border-radius: 8px;
  padding: 16px 18px;
  margin: 16px 0 20px;
}

.callout p { margin: 0; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  margin: 8px 0 20px;
}

th, td {
  text-align: left;
  vertical-align: top;
  padding: 9px 10px;
  border: 1px solid var(--line);
}

th { background: var(--callout); font-weight: 500; }

details {
  border-bottom: 1px solid var(--line);
  padding: 10px 0;
}

details summary {
  cursor: pointer;
  font-weight: 500;
  list-style: none;
}

details summary::-webkit-details-marker { display: none; }
details summary::before { content: "▸"; display: inline-block; width: 18px; color: var(--faint); transition: transform 0.15s; }
details[open] summary::before { transform: rotate(90deg); }
details p, details ul { margin-left: 18px; }

hr { border: 0; border-top: 1px solid var(--line); margin: 36px 0; }

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 12px; margin: 24px 0; }

.card {
  display: block;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 16px 18px;
  text-decoration: none;
  color: var(--text);
  transition: background 0.15s;
}

.card:hover { background: var(--callout); }
.card strong { display: block; margin-bottom: 2px; }
.card span { color: var(--muted); font-size: 14px; }

footer {
  max-width: 760px;
  margin: 0 auto;
  padding: 24px;
  border-top: 1px solid var(--line);
  color: var(--faint);
  font-size: 13px;
}

@media (max-width: 560px) {
  main { padding: 36px 16px 72px; }
  .topbar-inner { padding: 10px 16px; }
  footer { padding: 20px 16px; }
  h1 { font-size: 32px; }
  .meta { grid-template-columns: 1fr; row-gap: 2px; }
  .meta dt { margin-top: 6px; }
  table { font-size: 14px; }
  th, td { padding: 8px; }
}