:root{color:#353151;font-synthesis:none;text-rendering:optimizelegibility;-webkit-font-smoothing:antialiased;--pink:#f45b87;--blue:#239fe0;--purple:#7652ce;--ball:64px;--slot:72px;background:#edf7ff;font-family:ui-rounded,Arial Rounded MT Bold,Trebuchet MS,system-ui,sans-serif}*{box-sizing:border-box}body{min-width:320px;margin:0}button,input{font:inherit}button,a{-webkit-tap-highlight-color:transparent;touch-action:manipulation}button{cursor:pointer;color:inherit}button:disabled{cursor:default;opacity:1}a{color:inherit;text-decoration:none}button:focus-visible,a:focus-visible{outline-offset:6px;outline:4px solid #44348c}[hidden]{display:none!important}svg{flex-shrink:0;width:26px;height:26px}#app{max-width:1200px;margin:auto;padding:20px 30px 22px}main{min-height:calc(100svh - 42px)}.icon-button{color:#6a6d91;background:#fff;border:0;border-radius:19px;justify-content:center;align-items:center;width:54px;height:54px;display:inline-flex;box-shadow:0 4px #dbe7f1}.icon-button:hover{background:#f9fcff}.icon-button:active{transform:translateY(3px);box-shadow:0 1px #dbe7f1}.sound-button{z-index:2;position:absolute;top:20px;right:max(30px,50vw - 570px)}.home-intro{text-align:center;padding:45px 0 25px}.home-name{color:var(--purple);font-size:27px;font-weight:900}.home-intro h1{letter-spacing:-.04em;margin:13px 0 5px;font-size:clamp(36px,6vw,53px);font-weight:900}.activity-library{max-width:420px;margin:auto}.activity-card{background:#fff;border-radius:36px;padding:12px;transition:transform .18s;display:block;box-shadow:0 9px #d7e5f2}.activity-card:hover{transform:translateY(-4px)rotate(-1deg)}.activity-card:active{transform:translateY(5px)}.activity-preview{background:#ede7ff;border-radius:27px;justify-content:center;align-items:center;min-height:268px;display:flex;position:relative}.mini-frame{background:#fff5d5;border:4px solid 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10px;display:flex}.equation{letter-spacing:-.03em;align-items:center;gap:14px;font-size:60px;font-weight:900;line-height:1.1;display:flex}.math-sign{color:#a4abc4;font-size:.7em}.pink-text{color:#dc3c71}.blue-text{color:#087fba}.equation-arrow{color:#a4abc4;font-size:32px;font-weight:700}.regrouped .equation{font-size:46px}.result-piece{color:#208655;background:#d7f3df;border-radius:22px;padding:8px 13px}.result-piece .equation{font-size:46px}.lesson-prompt h2{letter-spacing:-.02em;margin:0 0 25px;font-size:29px;font-weight:900;line-height:1.3}.lesson-prompt h2:focus{outline:none}.manipulatives{justify-content:center;align-items:center;gap:18px;margin:0 auto;display:flex}.number-group{flex-direction:column;align-items:center;display:flex}.ten-frame{grid-template-columns:repeat(5, var(--slot));background:#fff1c9;border:4px solid #efcb70;border-radius:27px;gap:8px;padding:14px;transition:background .18s,border-color .18s;display:grid;box-shadow:0 7px 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#ceeaff;border-radius:29px;align-content:center;gap:12px;padding:20px;transition:background .2s,border-color .2s;display:grid}.loose-slot{width:var(--ball);height:var(--ball);place-items:center;display:grid}.count-tag{color:#fff;font-size:24px;font-weight:900;display:none}.show-hint .count-tag{display:inline}.show-hint .empty-dot{background:#ffe38c;border:3px dashed #c68e24;animation:1s ease-in-out 3 hint-pulse}.show-hint .loose-balls{background:#ceeaff;border-color:#4aaae2}.count-these .loose-balls{border-color:#71bdea}.frame-count{color:#9a742d;margin-top:14px;font-size:25px;font-weight:900}.frame-count>span{color:#a88b50;font-size:17px}.move-arrow{color:#95acc9;margin-top:-30px;font-size:42px;font-weight:900}.points-to-frame{color:#499fd8;animation:1.2s ease-in-out 3 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