#main .source-panel{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(220px,.65fr);gap:26px;align-items:start}
#main .intro-content>.start-button{display:flex;margin-inline:auto}
#main .source-panel img{width:100%;max-height:350px;object-fit:cover;border-radius:10px}
#main .source-panel .reading{height:100%}
#main .experiment-gallery{display:grid;grid-template-columns:repeat(5,minmax(90px,1fr));gap:12px;margin:22px 0}#main .experiment-gallery figure{margin:0;text-align:center;background:var(--cream);padding:10px}#main .experiment-gallery img{width:100%;height:140px;object-fit:contain}#main .experiment-gallery figcaption{font-size:13px;margin-top:8px}
#main .timeline{display:grid;gap:14px;counter-reset:step}
#main .timeline article{display:grid;grid-template-columns:70px 1fr;gap:18px;background:#f3f2f2;border-left:5px solid var(--orange);padding:19px}
#main .timeline article::before{counter-increment:step;content:counter(step,upper-roman);width:52px;height:52px;border-radius:50%;display:grid;place-items:center;background:var(--orange);color:#fff;font-weight:800}
#main .timeline h3{margin:0 0 7px}#main .timeline p{margin:0}#main .timeline img{width:100%;max-width:260px;max-height:160px;object-fit:cover;margin-top:12px;border-radius:7px}
#main .nature-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin:22px 0}
#main .nature-grid article{padding:18px;border-top:5px solid var(--orange);background:var(--cream)}#main .nature-grid h3{margin-top:0}#main .nature-grid p:last-child{margin-bottom:0}
#main .answer-actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-top:10px}#main .locked-note{font-size:13px;color:#765f54}#main .feedback[hidden]+.locked-note{display:none}#main .feedback h4{margin:0 0 8px;color:var(--rust)}
#main .binary-list{display:grid;gap:14px}#main .binary-item{border:1px solid var(--line);padding:17px;background:#fff}#main .binary-item fieldset{margin:0;border:0;padding:0}#main .binary-item legend{padding:0 0 12px}
#main .article-copy h3{margin:24px 0 8px;color:#873a24}#main .article-copy .facts{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}#main .article-copy .facts div{background:#f4f1ef;padding:14px;border-left:4px solid var(--orange)}
#main .self-form{border:1px solid var(--line);padding:20px;background:#fff}
#main .completion{margin:24px 0;padding:20px;background:var(--cream);border:1px solid #e1c9ba}#main .completion button{width:100%;font-size:18px}#main .completion-status{margin:0 0 12px}#main .done-banner{background:#e8f3e8;border-left:5px solid #3c7b45;padding:18px;margin-top:14px}
#main .concept-card .card-text{min-height:132px}#main .concept-card.visited{border-color:#3c7b45}#main .concept-card.visited .open-label{color:#34713d}#main .cards .card img{display:none}
#main .visually-hidden{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
@media(max-width:760px){#main .source-panel{grid-template-columns:1fr}#main .experiment-gallery{grid-template-columns:repeat(2,1fr)}#main .nature-grid{grid-template-columns:1fr}#main .timeline article{grid-template-columns:48px 1fr;padding:14px;gap:12px}#main .timeline article::before{width:40px;height:40px}}