.formula-pad{padding:26px}.formula-pad.compact{padding:16px 20px;border-top:1px solid var(--line)}.formula-big{font-size:clamp(22px,3vw,34px);font-weight:900;letter-spacing:-.03em;color:#20262d;margin-bottom:14px}.formula-pad p{margin:0;color:var(--muted);line-height:1.7}.lesson-table{width:100%;border-collapse:collapse;font-size:14px}.lesson-table th,.lesson-table td{border:1px solid var(--line);padding:11px 12px;text-align:center}.lesson-table th{background:#f2f4f6;font-weight:850}.lesson-code{margin:0;padding:24px;background:#11151a;color:#e8f0f5;min-height:100%;overflow:auto;font-size:14px;line-height:1.65}.code-tree{padding:28px;text-align:center}.code-tree .root{font-size:32px}.tree-row{display:grid;grid-template-columns:repeat(2,1fr);gap:14px;max-width:420px;margin:10px auto}.tree-row.leaves{grid-template-columns:repeat(4,1fr)}.tree-row span{padding:10px;border:1px solid var(--line);border-radius:12px;background:#f8fafb;font-weight:850}.tree-row .used{background:var(--red-soft);border-color:#ffd0d4;color:var(--red-dark)}.tree-row .free{background:var(--green-soft);border-color:#ccecdc;color:var(--green-dark)}.formula-list{display:grid;gap:12px;padding:24px}.formula-list code{padding:14px 16px;background:#f4f6f8;border-radius:12px;font-size:15px}.slot-row{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;padding:28px}.slot-row span{display:grid;place-items:center;min-height:70px;border:2px dashed #cdd4dc;border-radius:16px;font-size:24px;font-weight:900}.slot-row .fixed{border-style:solid;border-color:#ccecdc;background:var(--green-soft);color:var(--green-dark)}.panel-copy{padding:0 24px 24px;margin:0;color:var(--muted);line-height:1.6}.ok-cell{background:var(--green-soft);color:var(--green-dark);font-weight:900}.block-strip{display:grid;grid-template-columns:1fr 2fr 1fr;gap:8px;padding:28px}.block-strip span{padding:16px 8px;border:1px solid var(--line);border-radius:12px;text-align:center;font-weight:850}.block-strip .active{background:var(--green-soft);border-color:#ccecdc;color:var(--green-dark)}
.quiz-stack{display:grid;gap:16px;margin-top:18px}.quiz-question{padding:20px;border:1px solid var(--line);border-radius:18px;background:#fff}.quiz-question h4{margin:0 0 14px;font-size:17px}.quiz-input-row{display:flex;gap:10px}.quiz-input-row input{min-width:0;flex:1;border:1px solid #d7dce2;border-radius:12px;padding:0 14px;min-height:46px;outline:0}.quiz-question.correct{border-color:#bfe7d4;background:var(--green-soft)}.quiz-question.wrong{border-color:#ffd0d4;background:var(--red-soft)}.quiz-feedback{min-height:20px;margin:10px 0 0;font-size:13px;font-weight:750}.quiz-question.correct .quiz-feedback{color:var(--green-dark)}.quiz-question.wrong .quiz-feedback{color:var(--red-dark)}.source-note{margin-top:22px;color:var(--muted);font-size:12px}.source-note a{color:var(--green-dark);font-weight:800}.lesson-nav-inline{display:flex;gap:10px;flex-wrap:wrap}.ready-chip{display:inline-flex;align-items:center;gap:6px;padding:6px 9px;border-radius:999px;background:var(--green-soft);color:var(--green-dark);font-size:11px;font-weight:850}
@media(max-width:700px){.quiz-input-row{flex-direction:column}.block-strip{padding:18px}.slot-row{padding:18px}.formula-pad{padding:20px}.tree-row.leaves{grid-template-columns:repeat(2,1fr)}}

/* v5: code examples for lessons 23–27 */
.code-pad{background:#11161b;color:#e9f0f5;border-radius:14px;padding:16px;overflow:auto}
.code-pad pre{margin:0;font:600 13px/1.65 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;white-space:pre-wrap}
.formula-pad p+p{margin-top:10px}
.lesson-nav-inline{display:flex;flex-wrap:wrap;gap:10px}
@media(max-width:700px){.lesson-nav-inline{width:100%}.lesson-nav-inline .btn{flex:1 1 180px}}

/* reveal panels */
.reveal-steps>[data-answer-panel]{display:none;padding:0 20px 16px 112px;color:#4d5661}
.reveal-steps>[data-answer-panel].open{display:block}
.reveal-steps>[data-answer-panel] p{margin:0}
@media(max-width:700px){.reveal-steps>[data-answer-panel]{padding:0 16px 16px}}