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/* Keep the answer controls within reach on small phones. */
.feedback:empty{display:none}
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/* Connect the movable diagram to the child's written arithmetic. */
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.notebook>summary{cursor:pointer;padding:10px 12px;color:var(--deep);font-size:15px;font-weight:500}
.notebook>summary span{float:right;font-size:13px;color:var(--muted);font-weight:400}
.nb-body{padding:0 13px 14px}.nb-intro{font-size:14px;color:var(--muted);line-height:1.65;border-top:1px solid var(--line);padding-top:10px}
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.nb-summary{border-top:1px solid #c5d5c7;margin-top:15px;padding-top:13px;font-size:14px}.nb-summary h3{font-size:15px;font-weight:600}.nb-summary ol{padding-left:22px}.nb-summary li{margin:8px 0}.nb-summary li span,.nb-summary li strong{display:block}.nb-summary li strong{font-size:18px;font-weight:500;overflow-wrap:anywhere}.nb-talk{border-left:3px solid #ba9d58;background:#f7f0dc;padding:8px 10px;margin:12px 0}.nb-summary>.btn{margin-top:10px}
.readout strong.goal{font-size:14px;white-space:normal;text-align:right;line-height:1.5}
@media(min-width:851px) and (min-aspect-ratio:3/4){.model-panel{position:sticky;top:12px}}
@media(max-width:480px){.notebook{margin-bottom:10px}.notebook>summary{padding:8px 10px;font-size:14px}.nb-body{padding:0 10px 12px}.nb-numbers{gap:5px}.nb-numbers>div{min-width:75px;padding:6px}.nb-numbers b{font-size:23px}.nb-numbers span{font-size:14px}.nb-check .btn,.nb-nav .btn{min-height:38px}.nb-intro{font-size:14px}}

.practice-toc-entry{margin-top:22px;border:1px solid #b4c9b9;border-radius:15px;padding:17px 20px;background:#fffdf5}.practice-toc-entry h2{font:500 21px/1.6 var(--serif)}.practice-toc-entry p{font-size:14px;color:var(--muted);margin:5px 0 12px}.practice-toc-entry .pdf-links{display:flex;gap:8px;flex-wrap:wrap}.practice-toc-entry .btn.primary{font-size:15px}