/* Reading layout only. Background layers and theme variables are unchanged. */
.chapter-kicker { margin: 0; font: 10px var(--font-mono); letter-spacing: .13em; text-transform: uppercase; color: var(--accent-strong); }
.unfolding .idea-body { padding: 30px clamp(22px, 5vw, 64px) 36px; }
.unfolding .unfolding-lead { font-family: var(--font-display); font-size: clamp(20px, 2.2vw, 25px); line-height: 1.6; color: var(--ink); max-width: 62ch; margin-bottom: 26px; }
.chapter-index { display: flex; flex-wrap: wrap; gap: 10px 22px; padding: 20px 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); margin-bottom: 10px; }
.chapter-index a { font: 11px var(--font-mono); line-height: 1.7; }
.unfolding-chapter { display: grid; grid-template-columns: 38px minmax(0,1fr); gap: 14px; padding: 28px 0 8px; }
.chapter-number { color: var(--accent-strong); font: 11px var(--font-mono); letter-spacing: .07em; }
.unfolding-chapter > .chapter-number { padding-top: 9px; }
.unfolding-chapter h3, .derivation-entry h3, .derivation-record h3 { margin: 0 0 17px; font: 500 clamp(22px,2.4vw,28px)/1.3 var(--font-display); letter-spacing: -.02em; }
.unfolding .unfolding-chapter p { max-width: 78ch; line-height: 1.85; margin-bottom: 18px; }
.unfolding-method { border-top: 1px solid var(--line); margin-top: 20px; padding-top: 24px; }
.unfolding .unfolding-method p { font-size: 13px; line-height: 1.8; max-width: 95ch; }
.unfolding .unfolding-method .unfolding-sources { font-size: 12px; color: var(--ink-3); }
.chapter-continue { display: inline-flex; align-items: center; gap: 25px; margin-top: 7px; padding: 12px 0; font-size: 14px; border-bottom: 1px solid var(--accent); }
.derivations-body { padding: 10px clamp(22px,5vw,64px) 32px; }
.derivation-entry { padding: 28px 0 30px; }
.derivation-entry + .derivation-entry, .derivation-record { border-top: 1px solid var(--line); }
.derivation-label { display: flex; align-items: center; flex-wrap: wrap; gap: 18px; margin-bottom: 18px; }
.derivation-entry p, .derivation-record p { max-width: 82ch; color: var(--ink-2); font-size: 15px; line-height: 1.85; margin: 0 0 18px; }
.derivation-entry .mono { overflow-wrap: anywhere; font-size: .9em; }
.derivation-entry .derivation-equation { font: 500 clamp(17px,2.2vw,24px)/1.7 var(--font-mono); color: var(--ink); border-left: 2px solid var(--accent); padding: 12px 0 12px 22px; margin: 24px 0; overflow-wrap: anywhere; }
.derivation-table { overflow-x: auto; margin: 24px 0; }
.derivation-table table { width: 100%; max-width: 850px; border-collapse: collapse; font-variant-numeric: tabular-nums; }
.derivation-table caption { text-align: left; color: var(--ink-3); padding-bottom: 13px; font-size: 12px; line-height: 1.7; }
.derivation-table th, .derivation-table td { padding: 13px 14px; border-bottom: 1px solid var(--line); text-align: left; font-size: 13px; line-height: 1.6; }
.derivation-table th { font-weight: 500; color: var(--ink); }
.derivation-table td { color: var(--ink-2); }
.derivation-table td:not(:first-child) { font-family: var(--font-mono); white-space: nowrap; }
.derivation-details { padding: 16px 0 0; border-top: 1px solid var(--line); }
.derivation-details summary { cursor: pointer; font-size: 13px; color: var(--accent-strong); line-height: 1.6; }
.derivation-details[open] summary { margin-bottom: 18px; }
.derivation-details p, .derivation-details li { font-size: 13px; line-height: 1.8; }
.derivation-details ul { color: var(--ink-2); padding-left: 20px; }
.derivation-details li { margin: 7px 0; }
.derivation-record { padding-top: 28px; }
.derivation-record > .panel-note { margin: 24px 0 0; font-size: 12px; }
@media (max-width: 700px) {
  .unfolding .idea-body { padding: 23px 20px 28px; }
  .chapter-index { gap: 10px 18px; }
  .unfolding-chapter { grid-template-columns: 23px minmax(0,1fr); gap: 10px; padding-top: 25px; }
  .unfolding-chapter h3 { font-size: 22px; }
  .unfolding .unfolding-chapter p { font-size: 14px; line-height: 1.85; }
  .derivations-body { padding: 5px 20px 25px; }
  .derivation-label .grade { font-size: 9px; letter-spacing: 0; }
  .derivation-entry p { font-size: 14px; }
  .derivation-table th, .derivation-table td { padding: 11px 9px; font-size: 12px; }
}