.lesson,.guided{margin:1.25rem 0 2rem}.guided-cta{text-align:center;margin-top:1.25rem}.lesson-fallback{color:var(--color-ink-soft);font-size:.95rem}.lesson-board{display:grid;grid-template-columns:repeat(var(--n),1fr);gap:1px;max-width:22rem;margin:0 auto;background:var(--color-border);border:2px solid var(--color-ink);border-radius:4px;overflow:hidden}.lesson-cell{aspect-ratio:1;border:0;background:var(--color-cream);font-family:Fraunces,Georgia,serif;font-size:clamp(.7rem,3.4vw,1.1rem);color:var(--color-ink);display:flex;align-items:center;justify-content:center;cursor:default;transition:background-color .4s ease,color .4s ease}.lesson-board.reduce .lesson-cell{transition:none}.lesson-cell.given{font-weight:600}.lesson-cell.placed{color:var(--accent, var(--color-sage));font-weight:600}.lesson-cell.cands{font-family:Inter,sans-serif;font-size:.55rem;color:var(--color-ink-soft);letter-spacing:.04em}.lesson-cell.cands.hl-unit,.lesson-cell.cands.hl-target,.lesson-cell.cands.hl-elim,.lesson-cell.cands.hl-block{color:#4b5563}.lesson-cell.hl-unit{background:#efe7d6}.lesson-cell.hl-target{background:#d9e6dd;outline:2px solid var(--color-sage);outline-offset:-2px}.lesson-cell.hl-elim{background:#f0dcd2;text-decoration:line-through}.lesson-cell.hl-block{background:#f0dcd2;outline:2px solid var(--color-terracotta);outline-offset:-2px}.lesson-cell.hl-place{background:#d9e6dd}.lesson-cell.clickable{cursor:pointer}.lesson-cell.clickable:hover{background:#d9e6dd}.lesson-cell:focus-visible{outline:2px solid var(--color-ink);outline-offset:-2px}.lesson-cell.box-r{box-shadow:inset -2px 0 0 var(--color-ink)}.lesson-cell.box-b{box-shadow:inset 0 -2px 0 var(--color-ink)}.lesson-cell.box-r.box-b{box-shadow:inset -2px 0 0 var(--color-ink),inset 0 -2px 0 var(--color-ink)}.lesson-caption{text-align:center;margin:.9rem 0 .6rem;min-height:2.6em;color:var(--color-ink)}.lesson-controls{display:flex;justify-content:center;gap:.5rem}.lesson-btn{font-family:Inter,sans-serif;font-size:.9rem;padding:.35rem .9rem;border:1px solid var(--color-border);border-radius:999px;background:var(--color-cream);color:var(--color-ink-soft);cursor:pointer;transition:all .15s ease}.lesson-btn:hover:not(:disabled){color:var(--accent, var(--color-sage));border-color:var(--accent, var(--color-sage))}.lesson-btn:disabled{opacity:.4;cursor:default}.lesson-btn:focus-visible{outline:2px solid var(--color-ink);outline-offset:2px}.learn-nav{display:flex;flex-wrap:wrap;gap:.5rem 1rem;margin:0 0 2rem;font-size:.95rem}.learn-nav a{color:var(--color-ink-soft);text-decoration:none}.learn-nav a:hover{color:var(--accent, var(--color-sage))}.learn-nav a[aria-current=page]{color:var(--color-ink);font-weight:600}.learn-next{margin-top:2.5rem}.learn-next a,.learn-prev a{color:var(--accent, var(--color-sage));text-decoration:none;font-weight:500}