:root{--chalk:#1F3A34;--paper:#FFFFFF;--paper-dim:#F0E9D6;--coral:#FF6B5D;--coral-dark:#E0503F;--teal:#2EC4B6;--teal-dark:#1FA093;--sun:#FFC93C;--ink:#1F3A34;--ink-soft:#5B7A70}*{box-sizing:border-box}.wrap{max-width:620px;margin:0 auto}header{text-align:center;margin-bottom:28px}.card{background:var(--paper);color:var(--ink);border-radius:22px;padding:28px 24px 26px;box-shadow:0 14px 0 rgb(0 0 0 / .14)}.card .sub{color:var(--ink-soft);font-size:15px;margin:0 0 20px}.chips{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:24px}.chip{font-family:'Fredoka',sans-serif;font-size:16px;font-weight:600;border:2px solid var(--ink);background:var(--paper);color:var(--ink);padding:7px 14px;border-radius:999px;cursor:pointer;transition:transform .12s ease,background .15s ease,color .15s ease}.chip:hover{transform:translateY(-2px)}.chip.active{background:var(--ink);color:var(--paper)}.chip:focus-visible{outline:3px solid var(--teal-dark);outline-offset:2px}.bar-block{margin-bottom:18px}.bar-label{display:flex;justify-content:space-between;align-items:baseline;margin-bottom:8px}.bar-label .name{font-weight:800;font-size:14px;color:var(--ink-soft)}.bar-label .frac{font-family:'Fredoka',sans-serif;font-weight:700;font-size:20px}.bar{display:flex;height:54px;border:3px solid var(--ink);border-radius:12px;overflow:hidden;background:var(--paper-dim)}.segment{flex:1 1 0%;border-right:2px solid rgb(31 58 52 / .18);animation:pop .28s ease}.segment:last-child{border-right:none}.segment.filled.a{background:var(--coral)}.segment.filled.b{background:var(--teal)}@keyframes pop{from{opacity:0;transform:scaleY(.6)}to{opacity:1;transform:scaleY(1)}}.stepper-row{display:flex;align-items:center;justify-content:center;gap:14px;margin:22px 0 6px}.step-btn{width:42px;height:42px;border-radius:50%;border:2px solid var(--ink);background:var(--paper);color:var(--ink);font-size:22px;font-weight:800;cursor:pointer;display:flex;align-items:center;justify-content:center;transition:transform .12s ease,background .15s ease}.step-btn:hover{background:var(--sun)}.step-btn:disabled{opacity:.35;cursor:not-allowed}.step-btn:focus-visible{outline:3px solid var(--teal-dark);outline-offset:2px}.multiplier-display{font-family:'Fredoka',sans-serif;font-size:18px;font-weight:600;min-width:68px;text-align:center}.equation{text-align:center;font-family:'Fredoka',sans-serif;font-size:clamp(18px, 4vw, 24px);font-weight:700;margin-top:14px;color:var(--coral-dark)}.equation span.eq-teal{color:var(--teal-dark)}@media (max-width:480px){.card{padding:22px 16px 20px}.bar{height:46px}}@media (prefers-reduced-motion:reduce){.segment{animation:none}.chip,.step-btn{transition:none}}.quiz-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:6px}.quiz-top h2{font-family:'Fredoka',sans-serif;font-size:22px;font-weight:600;margin:0}.scoreboard{display:flex;gap:16px;font-family:'Fredoka',sans-serif;font-size:14px;font-weight:600;color:var(--ink-soft)}.scoreboard b{color:var(--ink)}.card .sub{color:var(--ink-soft);font-size:15px;margin:6px 0 0}.question{text-align:center;margin:18px 0 22px}.question .q-lead{font-size:15px;color:var(--ink-soft);margin-bottom:6px}.question .q-frac{font-family:'Fredoka',sans-serif;font-size:40px;font-weight:700}.options{display:grid;grid-template-columns:1fr 1fr;gap:12px}.option{font-family:'Fredoka',sans-serif;font-size:22px;font-weight:600;padding:16px 10px;border:2px solid var(--ink);border-radius:14px;background:var(--paper);color:var(--ink);cursor:pointer;transition:transform .12s ease,background .15s ease,border-color .15s ease}.option:hover{transform:translateY(-2px)}.option:focus-visible{outline:3px solid var(--teal-dark);outline-offset:2px}.option.correct{background:var(--teal);border-color:var(--teal-dark);color:#16332C}.option.wrong{background:var(--coral);border-color:var(--coral-dark);color:var(--paper)}.option[disabled]{cursor:default}.feedback{min-height:26px;text-align:center;font-weight:800;font-family:'Fredoka',sans-serif;margin-top:16px;font-size:16px}.feedback.good{color:var(--teal-dark)}.feedback.bad{color:var(--coral-dark)}.next-btn{display:block;margin:14px auto 0;font-family:'Fredoka',sans-serif;font-weight:600;font-size:15px;background:var(--ink);color:var(--paper);border:none;padding:10px 22px;border-radius:999px;cursor:pointer;visibility:hidden;transition:transform .12s ease}.next-btn.show{visibility:visible}.next-btn:hover{transform:translateY(-2px)}.next-btn:focus-visible{outline:3px solid var(--sun);outline-offset:2px}footer{text-align:center;color:#9FBDB3;font-size:13px;margin-top:22px}@media (max-width:480px){.card{padding:22px 16px 20px}}@media (prefers-reduced-motion:reduce){.option,.next-btn{transition:none}}