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20px #0000002e}.lesson-article .article-footer{border-top:1px solid var(--border);color:var(--text-muted);text-align:center;padding:24px 0;font-size:11px}.lesson-article mark{background:var(--accent-yellow-soft);color:var(--accent-yellow);border-radius:3px;padding:0 4px;font-weight:700}.lesson-article kbd{background:var(--bg-elevated);border:1px solid var(--border-md);border-radius:var(--r-sm);font-family:var(--font-mono);color:var(--text-primary);padding:1px 6px;font-size:11px;display:inline-block}