.chair-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px;margin:20px 0}.chair-panel h3{text-align:center;font-size:16px;color:#506178;margin:0 0 9px}.chair-svg{display:block;width:100%;height:auto;border:1px solid #d4deea;border-radius:12px;background:white}.chair-single{max-width:690px;margin:20px auto}.chair-bond{stroke:#111;stroke-width:2.2;stroke-linecap:round;fill:none}.chair-atom{font:23px Arial,sans-serif;fill:#111}.chair-number{font:13px Arial,sans-serif;fill:#697b92}.chair-slot circle{fill:#f6f8fc;stroke:#9aafca;stroke-width:1.5;stroke-dasharray:4 3}.chair-slot text{font:21px Arial;fill:#506178}.chair-slot{cursor:pointer}.chair-slot:focus circle,.chair-slot:hover circle{stroke:#4169e1;stroke-width:2;fill:#edf2ff}.chair-slot.filled circle{fill:white;stroke:#4169e1;stroke-dasharray:none}.chair-target{stroke:#4169e1;stroke-width:2;fill:#4169e112}.chair-answer-row{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:12px;margin:15px 0}.chair-answer-row strong{min-width:90px}.chair-answer-row button[aria-pressed=true],.chair-pieces button[aria-pressed=true]{background:#163d68;color:white;border-color:#163d68}.chair-pieces{display:flex;flex-wrap:wrap;gap:10px;margin:12px 0}.chair-pieces button{padding:10px 18px}.chair-pieces button:disabled{opacity:.45}.chair-choice{width:100%;padding:8px;color:#132c48}.chair-choice[aria-pressed=true]{border-color:#4169e1;box-shadow:0 0 0 2px #4169e1}.chair-choice .chair-svg{border:0}.chair-choice strong{display:block;padding:5px}.chair-game #ch-progress{height:100%;background:#c14b13}.chair-game #ch-feedback{min-height:54px;padding:14px 16px;background:#f2f5f9;border:2px solid transparent;border-radius:10px;line-height:1.5;margin-top:16px}.chair-game #ch-feedback[data-state=correct]{background:#e9f7ed;color:#166534;border-color:#228443}.chair-game #ch-feedback[data-state=incorrect]{background:#fff0f0;color:#a51c26;border-color:#c8323e}.chair-game #ch-hint{margin-left:auto}.chair-help{color:#506178;line-height:1.5}.chair-game button:focus-visible{outline:3px solid #4169e1;outline-offset:3px}@media(max-width:900px){.chair-grid{grid-template-columns:1fr}}@media(min-width:901px){.practice-home{grid-template-columns:repeat(2,1fr)}}

.chair-slot.filled circle{fill:transparent;stroke:transparent}.chair-slot.filled .chair-atom{font:23px Arial,sans-serif;fill:#111}.chair-slot.filled:focus circle{stroke:#4169e1;fill:transparent}
.chair-bond{stroke-width:2;stroke-linejoin:round}