body{background:#f5f6ef;padding-bottom:env(safe-area-inset-bottom);font-family:Arial,sans-serif}body>header.mobile-header{padding:14px 16px;background:#284f42;color:white;border:0;max-width:720px;gap:12px}header .secondary{background:#ffffff16;color:white;border-color:#ffffff30;font-size:12px;padding:10px}main{max-width:720px;padding:16px;margin:auto}h1{font-size:28px;letter-spacing:-.7px}h2{font-size:19px;line-height:1.45}.mode-switch{display:flex;gap:6px;padding:10px 16px;background:#fffefa;max-width:720px;margin:auto;position:sticky;top:0;z-index:3}.mode-switch button{flex:1;border:0;border-radius:10px;background:#edf0e6;padding:13px;font-weight:bold;color:#53684d;font-size:16px}.mode-switch [aria-pressed=true]{background:#dce9cc;color:#25492d}.topic-label,form label{display:flex;flex-direction:column;gap:9px;font-size:14px;font-weight:bold}select,input{font:inherit;min-height:46px;border:2px solid #bdcdae;border-radius:9px;background:white;color:#284f42;padding:9px;max-width:100%}select{font-size:16px}#theory-frame{width:100%;height:calc(100dvh - 215px);min-height:420px;border:0;margin-top:12px;background:#fffefa;border-radius:12px}#start-card{display:grid;gap:18px;margin:24px 0}.primary{font-size:15px;min-height:48px;border-radius:12px;padding:14px 19px}.small{font-size:13px;color:#61745a;line-height:1.6}#setup>p{line-height:1.7;font-size:15px}.card-progress{margin-bottom:20px}.card-progress>div{display:flex;justify-content:space-between;align-items:center;gap:12px;font-size:13px;font-weight:bold}.text-button{border:0;background:none;color:#5b7254;padding:8px 0;font-size:12px}progress{display:block;width:100%;height:13px;margin-top:9px;border:0;border-radius:20px;overflow:hidden;accent-color:#6e994e}progress::-webkit-progress-bar{background:#e1e8d9}progress::-webkit-progress-value{background:#709d4f;border-radius:20px}.task-heading{display:flex;justify-content:space-between;color:#6b7d62;font-size:12px;gap:10px}.current-question{margin:12px 0 17px}.mobile-board{background:#edf1e5;border-radius:15px;padding:12px;text-align:center;overflow:auto}.mobile-board .board-caption{font-size:11px;margin:6px 0}.builder-legend{font-size:12px;min-height:0}.builder-table-wrap{--column-cell:46px}.division-work{--column-cell:44px}.builder-scroll{padding:5px 0}.builder-table .slot{min-height:44px;height:44px;font-size:28px;width:42px}.builder-table .carry-slot{min-height:36px;height:36px}.builder-equation{font-size:23px;margin:5px 0}.table-example{font-size:29px;display:flex;align-items:center;justify-content:center;gap:10px;min-height:110px}.table-example input{width:88px;font-size:28px;text-align:center}#column-answer{margin-top:16px;display:flex;flex-wrap:wrap;gap:12px;align-items:center}#column-answer>input{width:120px;font-size:24px}#column-answer .check{margin-left:auto}.feedback{min-height:0;margin:12px 0;font-size:14px}.feedback:empty{display:none}.task-actions{display:flex;justify-content:flex-end;margin:14px 0}.place-number{font-size:40px;font-weight:bold;margin:15px}.place-inputs{display:flex;gap:7px;justify-content:center}.place-inputs label{flex:1;min-width:0;font-size:12px}.place-inputs input{width:100%;font-size:20px;text-align:center;margin-top:8px;padding:8px 2px}.story-text{text-align:left;line-height:1.7;font-size:16px;margin:5px}.story-history{text-align:left;font-size:14px;color:#496d3f}.story-slots{display:grid;grid-template-columns:1fr 52px 1fr 15px 1fr;gap:5px;width:100%;align-items:center}.story-slots input{width:100%;min-width:0;padding:8px 2px;text-align:center;font-size:21px}.story-slots select{padding:5px;min-width:0;font-size:20px}.borrow-actions{display:flex;gap:12px}.borrow-actions button{padding:13px;background:#e0ebd4;border:1px solid #9eb38d;border-radius:10px;color:#2d5038;font-weight:bold}.celebration{text-align:center;padding:10px}.celebration img{width:100%;max-width:380px}.celebration h1{margin:10px}.celebration p{font-size:17px;line-height:1.7}.celebration .small{font-size:14px}@media(max-width:360px){main{padding:12px}.builder-table-wrap{--column-cell:40px}.builder-table .slot{width:36px}.place-inputs input{font-size:17px}.table-example{font-size:25px}}@media(prefers-reduced-motion:no-preference){.celebration img{animation:reward-pop .6s ease-out}@keyframes reward-pop{from{transform:scale(.7);opacity:0}to{transform:scale(1);opacity:1}}}