.lesson{grid-template-columns:290px minmax(0,1fr);align-items:start;gap:56px;padding-top:44px;padding-bottom:80px;display:grid}.rail{position:sticky;top:86px}.rail-back{margin-bottom:18px;text-decoration:none;display:block}.rail-back:hover{color:var(--felt)}.rail-no{color:var(--felt);font-variation-settings:"opsz" 144, "SOFT" 100, "WONK" 1;font-size:84px;font-style:italic;line-height:.85}.rail-title{margin:10px 0 8px;font-size:30px;font-weight:400;line-height:1.1}.rail-sum{color:var(--ink-2);margin:0 0 22px;font-size:15px}.rail-steps{border-top:1px solid var(--rule-strong);margin:0 0 18px;padding:0;list-style:none}.rail-steps li{border-bottom:1px solid var(--rule)}.rail-steps button{text-align:left;cursor:pointer;width:100%;color:var(--ink-2);background:0 0;border:0;grid-template-columns:26px 1fr;gap:10px;padding:9px 2px;font-size:14px;display:grid}.rail-steps button:hover{color:var(--ink)}.rail-steps .cur button{color:var(--ink);box-shadow:inset 3px 0 0 var(--felt);padding-left:10px;font-weight:600}.rail-steps .ok .mono{color:var(--good)}.pane{min-width:0}.pane-top{margin-bottom:14px}.pane-nav{border-top:1px solid var(--rule);justify-content:space-between;gap:12px;margin-top:36px;padding-top:20px;display:flex}.explain h2,.finished h2{margin:0 0 22px;font-size:clamp(40px,5.6vw,72px)}.explain-body{max-width:38em}.explain-body p{color:var(--ink-2);margin:0 0 16px;font-size:19px;line-height:1.6}.explain-body strong{color:var(--ink)}.visual{flex-direction:column;align-items:flex-start;gap:22px;margin-top:28px;display:flex}.visual>*{max-width:100%}.staff-box{border:1px solid var(--rule);background:#f7f1e5;border-radius:3px;width:min(560px,100%);padding:4px 10px}.board{background:var(--lacquer);border-radius:6px;width:100%;margin-top:18px;padding:14px 14px 12px}.task .prompt{max-width:24em;margin:8px 0 18px;font-size:clamp(26px,3.4vw,40px);font-weight:400;line-height:1.15}.task .prompt strong{color:var(--felt);font-weight:500}.status{font-family:var(--mono);border-left:3px solid var(--rule-strong);background:var(--paper-2);padding:10px 14px;font-size:14px;display:inline-block}.status.yes{border-left-color:var(--good);color:#3e5a1d}.status.no{border-left-color:var(--wrong);color:#8c2219}.task-foot{flex-wrap:wrap;align-items:center;gap:16px;margin-top:14px;display:flex}.hint{color:var(--ink-3);font-size:14px}.need-input{border:1px dashed var(--rule-strong);border-radius:4px;flex-direction:column;align-items:flex-start;gap:12px;padding:16px 18px;display:flex}.need-input p{margin:0;font-size:19px}.need-input .err{color:var(--wrong);font-size:13px}.quiz{grid-template-columns:minmax(0,1.3fr) minmax(0,1fr);align-items:center;gap:32px;margin-bottom:18px;display:grid}.quiz-staff{border:1px solid var(--rule);background:#f7f1e5;border-radius:4px;padding:8px 18px;transition:background .2s}.quiz-staff.good{background:#eaf0d8}.quiz-staff.wrong{background:#f6dcd6;animation:.3s shake}@keyframes shake{25%{transform:translate(-4px)}75%{transform:translate(4px)}}.qs{font-size:72px;line-height:1}.qs span{color:var(--ink-3);font-size:30px}.quiz-score{flex-direction:column;align-items:flex-start;gap:8px;display:flex}.yes-text{color:#3e5a1d;margin:4px 0 0}.reveal{color:var(--felt);margin:0;font-size:22px}.dark-panel{background:var(--lacquer);border-radius:6px;margin-top:6px;overflow:hidden}.finished .try ul{border-top:1px solid var(--rule-strong);margin:8px 0 0;padding:0;list-style:none}.finished .try li a{border-bottom:1px solid var(--rule);padding:10px 0;font-size:18px;text-decoration:none;display:block}.finished .try li a:hover .serif{color:var(--felt)}.finished .muted{color:var(--ink-3);font-size:13px}@media (max-width:900px){.lesson{grid-template-columns:1fr;gap:24px;padding-top:24px}.rail{position:static}.rail-steps{display:none}.rail-no{font-size:54px}.quiz{grid-template-columns:1fr}}.board svg{max-height:210px}.quiz-staff svg{margin:0 auto;max-width:420px!important}