/* === responsive.css — site-13 options academy === */
@media(max-width:960px){
  .hero__inner{grid-template-columns:1fr;gap:32px}
  .hero__text h1{font-size:clamp(28px,5vw,42px)}
  .editorial{grid-template-columns:1fr}
  .editorial--rev{direction:ltr}
  .content-block{grid-template-columns:1fr}
  .curriculum-grid{grid-template-columns:repeat(2,1fr)}
  .greeks-grid{grid-template-columns:repeat(3,1fr)}
  .payoff__grid{grid-template-columns:1fr}
  .footer__grid{grid-template-columns:1fr 1fr}
  .topic-nav{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:768px){
  .mastnav{display:none;position:fixed;top:56px;left:0;right:0;bottom:0;background:var(--bg);flex-direction:column;padding:24px;gap:0;z-index:99}
  .mastnav.is-open{display:flex}
  .mastnav a{padding:14px 0;font-size:16px;border-bottom:1px solid var(--border-light)}
  .mastnav a.is-active{border-bottom:none;border-left:3px solid var(--primary);padding-left:12px}
  .menu-btn{display:block}
  .hero{padding:40px 0 32px}
  .hero-diagram{padding:16px}
  .hero-diagram__canvas{height:200px;margin-left:32px}
  .section{padding:40px 0}
  .payoff-section{padding:20px}
  .payoff__chart{height:240px;margin-left:36px}
  .curriculum-grid{grid-template-columns:1fr}
  .greeks-grid{grid-template-columns:repeat(2,1fr)}
  .payoff__metrics{grid-template-columns:1fr}
  .footer__grid{grid-template-columns:1fr;gap:20px}
  .footer__bottom{flex-direction:column;gap:12px;text-align:center}
  .cta-banner{padding:32px 20px}
  .diff-tabs{flex-wrap:wrap}
  .topic-nav{grid-template-columns:1fr 1fr}
}
@media(max-width:480px){
  .shell{padding:0 16px}
  .hero__ctas{flex-direction:column}
  .hero__ctas .btn{width:100%;justify-content:center}
  .hero-diagram__canvas{height:160px;margin-left:24px}
  .payoff__chart{height:200px;margin-left:28px}
  .payoff__toggle{flex-direction:column}
  .diff-tabs{flex-direction:column}
  .diff-tab{text-align:center}
  .payoff__metrics{grid-template-columns:1fr}
  .greeks-grid{grid-template-columns:1fr}
  .cta-banner__actions{flex-direction:column}
  .cta-banner__actions .btn{width:100%;justify-content:center}
}