.product-intro{display:grid;grid-template-columns:minmax(0,1.6fr) minmax(0,1fr);gap:4rem;align-items:center}
.product-intro h1{max-width:17ch;font-size:clamp(2.5rem,5vw,4.5rem)}
.lead{font-size:1.2rem;max-width:48ch;color:var(--muted);margin:1.5rem 0}
.formula-note{padding:2rem;border-left:3px solid var(--brand);background:var(--surface-soft)}
.formula-display{font-family:ui-monospace,monospace;font-size:1.5rem;line-height:1.8;font-variant-numeric:tabular-nums}
.formula-display strong{display:block;font-size:2.4rem;color:var(--brand-dark)}
.product-section{border-top:1px solid var(--line)}
.product-section h2{font-size:clamp(1.7rem,3vw,2.6rem);max-width:25ch;margin-top:0}
.method-list{padding-left:1.4rem;max-width:65ch;font-size:1.15rem}
.method-list li{margin:1.5rem 0;padding-left:.5rem}.method-list strong{display:block}
.product-columns{display:grid;grid-template-columns:1fr 1fr;gap:4rem}
.product-section details{max-width:65ch;padding:.8rem 0;border-bottom:1px solid var(--line)}
.product-section summary{min-height:2.75rem;align-content:center}
.guide{max-width:70ch}.guide h1{max-width:20ch}.guide h2{font-size:1.8rem}.guide code{overflow-wrap:anywhere}.guide .example{padding:1rem;border-left:3px solid var(--brand);background:var(--surface-soft);font-variant-numeric:tabular-nums}
@media(max-width:800px){.product-intro,.product-columns{grid-template-columns:1fr;gap:2rem}}