.guide-header { display: flex; justify-content: space-between; align-items: center; gap: 24px; min-height: 80px; border-bottom: 1px solid var(--line); }
.guide-header nav { display: flex; gap: 26px; font-size: 14px; }
.guide-intro { padding-block: 80px 64px; max-width: 940px; }
.guide-intro h1 { font-size: clamp(48px, 6vw, 80px); line-height: 1.03; letter-spacing: -.035em; font-weight: 550; }
.guide-intro p { font-size: 21px; line-height: 1.6; color: var(--muted); max-width: 58ch; margin-block: 28px 20px; }
.guide-intro > a { color: var(--green); font-size: 15px; }
.guide-layout { display: grid; grid-template-columns: 250px minmax(0, 820px); gap: clamp(40px, 6vw, 100px); }
.guide-contents { align-self: start; position: sticky; top: 30px; border-top: 1px solid var(--line-strong); padding-top: 20px; }
.guide-contents h2 { font-size: 17px; font-weight: 550; }
.guide-contents ol { list-style: none; padding: 0; margin-top: 16px; }
.guide-contents a { display: block; padding-block: 9px; font-size: 14px; text-decoration: none; color: var(--muted); }
.guide-contents a:hover { color: var(--green); text-decoration: underline; }
.guide-body { min-width: 0; }
.guide-body section { border-top: 1px solid var(--line-strong); padding-block: 28px 60px; scroll-margin-top: 20px; }
.guide-body h2 { font-size: clamp(28px, 3vw, 38px); font-weight: 550; line-height: 1.15; letter-spacing: -.025em; margin-bottom: 24px; }
.guide-body h3 { font-size: 23px; font-weight: 550; line-height: 1.25; margin-block: 34px 16px; }
.guide-body p, .guide-body li, .guide-body dd { max-width: 74ch; color: var(--muted); line-height: 1.75; }
.guide-body p { margin-block: 18px; }
.guide-body a:not(.button) { color: var(--green); }
.guide-body ul, .guide-body ol { padding-left: 24px; }
.guide-body li { margin-bottom: 12px; padding-left: 4px; }
.guide-body code { font-size: 13px; overflow-wrap: anywhere; }
.guide-chain { display: flex; flex-direction: column; gap: 20px; margin-block: 28px; }
.guide-chain span { border: 1px solid var(--line-strong); background: var(--mint); position: relative; padding: 16px 20px; border-radius: 12px; font-size: 15px; }
.guide-chain span + span::before { content: ""; width: 1px; height: 20px; background: var(--diagram-line); position: absolute; left: 30px; top: -21px; }
.guide-equation { padding: 24px; border-radius: 12px; background: var(--mint); margin-block: 26px; }
.guide-equation code { display: block; color: var(--green); margin-block: 8px; }
.guide-equation p { font-size: 14px; margin-bottom: 0; }
.guide-facts { margin-block: 26px; }
.guide-facts > div { border-top: 1px solid var(--line); padding-block: 18px; }
.guide-facts dt { font-weight: 550; margin-bottom: 7px; }
.guide-facts dd { margin: 0; font-size: 15px; }
.guide-footer { display: flex; flex-wrap: wrap; gap: 24px; padding-block: 30px; border-top: 1px solid var(--line); font-size: 14px; }
@media (max-width: 900px) {
  .guide-layout { grid-template-columns: 1fr; gap: 30px; }
  .guide-contents { position: static; }
  .guide-contents ol { display: grid; grid-template-columns: 1fr 1fr; column-gap: 24px; }
}
@media (max-width: 600px) {
  .guide-header { align-items: start; flex-direction: column; padding-block: 24px; gap: 20px; }
  .guide-header nav { flex-wrap: wrap; gap: 12px 24px; font-size: 13px; }
  .guide-intro { padding-block: 48px; }
  .guide-intro p { font-size: 18px; }
  .guide-contents ol { grid-template-columns: 1fr; }
  .guide-body p, .guide-body li { font-size: 15px; }
  .guide-equation { padding: 18px; }
}

/* Optional detail follows its short chapter overview, not eight stacked players. */
.walkthrough-detail { margin-block: 24px; scroll-margin-top: 24px; }
.walkthrough-detail > summary { cursor: pointer; border-block: 1px solid var(--line-strong); padding: 16px 4px; color: var(--ink); font-size: 16px; font-weight: 550; }
.walkthrough-detail > summary span { display: block; margin: 4px 0 0 18px; font-size: 12px; font-weight: 400; color: var(--muted); }
.walkthrough-detail > summary:hover { color: var(--green); }
.walkthrough-detail[open] > summary { border-bottom: 0; }
.guide-body .explainer-steps { padding: 0; }
.guide-body [data-scene] { max-width: none; margin: 0; padding: 26px 24px; }
.guide-body .step-description p { font-size: 14px; margin: 0; line-height: 1.65; }
.guide-body .motion-note { margin: 12px 0 0; }
.guide-body .step-explainer { margin: 0; }
@media (max-width: 600px) {
  .guide-body [data-scene] { padding: 22px 16px; }
}

.guide-intro > a { text-underline-offset: 5px; }
.guide-contents a { min-height: 44px; }
.guide-body .step-explainer figcaption { line-height: 1.65; }

.guide-contents > summary { font-size: 17px; font-weight: 550; cursor: pointer; min-height: 44px; }
.guide-contents nav > p { color: var(--green); font-size: 13px; font-weight: 550; margin-top: 22px; }
.guide-contents ol { margin-block: 8px 0; }
.guide-contents li { margin: 0; }
@media (max-width: 900px) {
  .guide-contents ol { grid-template-columns: 1fr; }
  .guide-contents nav { display: grid; grid-template-columns: 1fr 1.5fr; column-gap: 20px; }
  .guide-contents nav > p { margin-top: 16px; }
}
@media (max-width: 600px) {
  .guide-contents nav { display: block; }
}