.guide80{margin:0 auto;padding:clamp(56px,7vw,100px) max(24px,5vw);max-width:1600px;border-top:1px solid color-mix(in srgb,currentColor 20%,transparent);color:var(--ui-fg);background:var(--ui-bg)}
.guide80 header{max-width:700px;margin-bottom:32px}.guide80 h2{font-size:clamp(30px,3.6vw,52px);line-height:1.2;margin:0 0 16px}.guide80 p{font-size:15px;line-height:1.75;margin:0}.guide80-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:6%;align-items:center}.guide80-drawing{border-radius:16px;background:color-mix(in srgb,currentColor 4%,transparent);padding:20px}.guide80-drawing svg{display:block;width:100%;height:auto}.guide80-caption{display:block;text-align:center;font-size:11px;opacity:.7}.guide80-copy article{display:flex;gap:22px;padding:22px 0;border-bottom:1px solid color-mix(in srgb,currentColor 20%,transparent)}.guide80-copy article>span{font-size:12px;opacity:.7;padding-top:5px}.guide80 h3{font-size:clamp(21px,2vw,29px);line-height:1.3;margin:0 0 10px}.guide80-bottom{display:grid;grid-template-columns:1.2fr 1fr;gap:6%;align-items:center;margin-top:48px}.guide80-film video{display:block;width:100%;height:auto;aspect-ratio:16/9;object-fit:cover;border-radius:12px}.guide80-film>p{font-size:11px;margin-top:10px;opacity:.7}.guide80 details{border-bottom:1px solid color-mix(in srgb,currentColor 20%,transparent);padding:17px 0}.guide80 summary{cursor:pointer;font-size:14px;font-weight:500}.guide80 details p{padding-top:12px;font-size:13px}.guide80 .btn{margin-top:22px}.guide80-flame{transform-origin:280px 230px;animation:flame80 4s ease-in-out infinite}@keyframes flame80{50%{transform:scale(.97,1.04);opacity:.65}}@media(prefers-reduced-motion:reduce){.guide80-flame{animation:none}}@media(max-width:720px){.guide80-grid,.guide80-bottom{grid-template-columns:1fr;gap:24px}.guide80-drawing{padding:8px 8px 16px}.guide80-bottom{margin-top:32px}.guide80-copy article{padding:16px 0}.guide80 p{font-size:14px}}

/* Reserve the taller answer at each viewport width so the adjacent diagram stays still. */
.fuel-questions{margin-top:14px}
.fuel-questions__buttons{display:flex;flex-wrap:wrap;gap:8px}
.fuel-questions__buttons button{display:flex;align-items:center;gap:10px;padding:9px 12px;min-height:44px;border:1px solid var(--line);border-radius:10px;background:transparent;color:inherit;font:inherit;cursor:pointer}
.fuel-questions__buttons button::after{content:'+';font-size:1.25em;line-height:1}
.fuel-questions__buttons button[aria-expanded="true"]{border-color:currentColor}
.fuel-questions__buttons button[aria-expanded="true"]::after{content:'−'}
.fuel-questions__buttons button:focus-visible{outline:2px solid currentColor;outline-offset:2px}
.fuel-questions__answers{display:grid;margin-top:10px}
.fuel-questions__answers>p{grid-area:1/1;align-self:start}
.fuel-questions__answers>p[aria-hidden="true"]{visibility:hidden}