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var(--ui)}.lesson-checkpoint{border:1px solid var(--line);border-radius:var(--learning-radius);background:var(--surface-soft);margin:28px 0;padding:0 24px 24px}.reader .lesson-checkpoint h2{margin-top:25px}.lesson-checkpoint fieldset{border:0;min-width:0;margin:15px 0;padding:0}.lesson-checkpoint legend{font:13px var(--ui);color:var(--muted);margin-bottom:12px}.lesson-checkpoint label{cursor:pointer;font:16px/1.6 var(--ui);align-items:flex-start;gap:12px;margin:12px 0;display:flex}.lesson-checkpoint label>span{overflow-wrap:anywhere;flex:1;min-width:0}.lesson-checkpoint input[type=radio]{margin-top:3px}#checkpoint-result:empty{display:none}.reader #lesson-body>.soft,.reader #lesson-body .lesson-stage>.soft{font:14px/1.7 var(--ui);color:var(--muted);background:var(--surface-soft);border-radius:7px;padding:15px 18px}.lesson-stage-bar{z-index:6;background:var(--panel);border:1px solid var(--line);border-left:5px solid var(--stage-understand-accent);box-shadow:0 8px 22px -12px 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