.masthead {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  width: min(1216px, calc(100% - 80px));
  margin: 0 auto;
  padding: 34px 0 30px;
  border-bottom: 1px solid var(--rule);
}
.site-link { display: flex; flex-direction: column; text-decoration: none; min-height: 48px; padding: 4px 0; }
.site-name { font-size: 20px; font-weight: 650; letter-spacing: -0.02em; }
.site-kind { font-size: 16px; color: var(--muted); }
.index-jump { display: inline-flex; align-items: center; gap: 18px; min-height: 48px; padding: 8px 16px; border: 1px solid var(--rule); border-radius: 12px; font-size: 16px; text-decoration: none; }
.index-arrow { font-size: 22px; }
.desk-frame { display: grid; grid-template-columns: 282px minmax(0, 1fr); grid-template-areas: "chapters reading"; align-items: start; gap: 50px; width: min(1216px, calc(100% - 80px)); margin: 42px auto 0; }
.chapter-panel { grid-area: chapters; min-width: 0; position: sticky; top: 24px; }
.reading-desk { grid-area: reading; min-width: 0; }
.desk-article { padding: 44px 46px 38px; border: 1px solid var(--rule); border-radius: 24px; background: var(--glass); backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px); box-shadow: 0 20px 60px rgba(13, 22, 34, 0.14), inset 0 1px rgba(255, 255, 255, 0.05); }

@media (max-width: 1100px) {
  .desk-frame { gap: 28px; grid-template-columns: 240px minmax(0, 1fr); }
  .desk-article { padding: 34px 30px; }
}
@media (max-width: 820px) {
  .masthead { width: calc(100% - 40px); gap: 16px; padding: 22px 0; align-items: flex-start; }
  .index-jump { max-width: 136px; flex-shrink: 0; line-height: 1.4; padding: 8px 12px; gap: 8px; }
  .desk-frame { width: calc(100% - 40px); margin-top: 24px; grid-template-columns: minmax(0, 1fr); grid-template-areas: "reading" "chapters"; gap: 32px; }
  .chapter-panel { position: static; scroll-margin-top: 20px; }
  .desk-article { padding: 28px 24px; border-radius: 18px; }
}
@media (max-width: 430px) {
  .masthead, .desk-frame { width: calc(100% - 32px); }
  .masthead { flex-wrap: wrap; gap: 12px; }
  .site-link { width: 100%; }
  .index-jump { max-width: none; min-height: 44px; }
  .desk-article { padding: 26px 22px; }
}
@media print {
  :root { --ink: #111; --muted: #333; --accent: #222; --rule: #aaa; }
  .guide-page { background: white; }
  .masthead, .desk-frame { width: 100%; }
  .desk-frame { display: block; }
  .chapter-panel, .index-jump, .skip-link { display: none; }
  .desk-article { border: none; padding: 0; background: none; box-shadow: none; }
}