:root{font-family:'Avenir Next','Segoe UI',sans-serif;color:#303f36;background:#f5f3ed;font-synthesis:none;--green:#3f6653;--muted:#74796f;--line:#e4e5db}*{box-sizing:border-box}body{margin:0}button,input,a{-webkit-tap-highlight-color:transparent}button,input{font:inherit}button{cursor:pointer}button:focus-visible,input:focus-visible,a:focus-visible{outline:3px solid #967549;outline-offset:4px}.header{max-width:1280px;margin:auto;display:flex;justify-content:space-between;align-items:center;padding:30px 5%;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:10px;color:#304d3d;text-decoration:none;font-weight:700;font-size:23px;letter-spacing:-1px}.brand-dinosaur{object-fit:contain;flex-shrink:0}.header-note{font-size:13px;color:var(--muted)}main{max-width:1170px;margin:auto;padding:30px 36px}.intro{text-align:center;margin-bottom:36px}.eyebrow{font-size:10px;letter-spacing:2.6px;font-weight:700;color:#7b826f;margin:0 0 14px}h1{font-family:'Avenir Next','Segoe UI',sans-serif;font-size:36px;line-height:1.3;letter-spacing:-1.6px;font-weight:600;margin:0 0 14px}h1 span{color:var(--green)}.intro>p:last-child{font-size:15px;color:var(--muted);margin:0}.workspace{display:block;border:1px solid #dedfd5;border-radius:22px;background:#fffefb;overflow:hidden;box-shadow:0 8px 35px #354f3d04}.abacus-panel{padding:30px 34px 25px}.panel-heading{display:flex;align-items:center;justify-content:flex-end;gap:12px}h2{font-size:19px;letter-spacing:-.5px;margin:0 0 7px;font-weight:600}.panel-heading p{font-size:12px;color:var(--muted);margin:0}.reset{display:inline-flex;align-items:center;justify-content:center;gap:11px;min-height:60px;padding:10px 22px 10px 12px;background:#d9eabd;border:3px solid #527248;border-radius:24px;box-shadow:0 5px 0 #527248;color:#304c2b;font-family:ui-rounded,"SF Pro Rounded","Avenir Next",sans-serif;font-size:20px;font-weight:800;line-height:1.2;white-space:nowrap;touch-action:manipulation}.reset-icon{display:grid;place-items:center;width:34px;height:34px;border-radius:50%;background:#f6faed;flex-shrink:0}.reset-icon svg{width:23px;height:23px}.reset:hover{background:#cfe3ae}.reset:active{transform:translateY(4px);box-shadow:0 1px 0 #527248}.reset:focus-visible{outline:3px solid #967549;outline-offset:7px}.frame{margin-top:30px;position:relative;padding:23px 13px;background:#f4f1e7;border-left:14px solid #c5ab82;border-right:14px solid #c5ab82;border-radius:13px;box-shadow:inset 0 2px 8px #83785910}.frame-cap{position:absolute;height:14px;left:-14px;right:-14px;background:#cfb78f;border-radius:6px;box-shadow:inset 0 -2px 1px #ad946727}.top{top:0}.bottom{bottom:0}.row{height:85px;position:relative;touch-action:pan-y}.row:before{content:'';position:absolute;left:0;right:0;top:39px;height:6px;background:#c6c3b3;border-radius:6px;box-shadow:inset 0 2px 2px #0000000e}.bead{position:absolute;top:20px;height:43px;width:7%;border:0;border-radius:6px;background:transparent;touch-action:none;padding:0}.bead img{display:block;width:100%;height:100%;object-fit:contain;pointer-events:none;user-select:none;-webkit-user-drag:none}.bead:hover{outline:2px solid #4b6c54;outline-offset:2px}.bead-instruction{display:flex;align-items:center;justify-content:center;gap:8px;color:#85897b;font-size:12px;margin-top:19px}.bead-instruction>span{font-size:19px}.footer-note{text-align:center;font-size:12px;color:#818674;margin:25px 0 0}.footer-note span{color:#9b986d;font-size:17px;vertical-align:middle;margin-right:6px}footer{max-width:1098px;margin:20px auto 0;padding:24px 0;border-top:1px solid var(--line);display:flex;justify-content:space-between;font-size:10px;color:#969a8d}@media(min-width:1200px){main{padding-top:30px}.intro{margin-bottom:43px}.abacus-panel{padding:32px 38px 28px}.row{height:94px}.bead{top:24px}.row:before{top:43px}}@media(max-width:760px){.header{padding:21px 23px}.brand{font-size:clamp(15px,4.7vw,21px);letter-spacing:-.5px}.header-note{display:none}main{padding:34px 16px 20px}h1{font-size:29px;letter-spacing:-1px}h1 span{display:block}.intro>p:last-child{font-size:13px}.workspace{grid-template-columns:1fr}.abacus-panel{padding:23px 19px}.frame{border-left-width:10px;border-right-width:10px;padding:17px 7px}.frame-cap{left:-10px;right:-10px;height:10px}.row{height:77px}.bead{height:40px;top:20px}.row:before{top:37px}footer{margin:10px 22px 0;padding:20px 0}footer>span:last-child{display:none}.panel-heading p{font-size:11px}}@media(prefers-reduced-motion:no-preference){.bead{transition:left .2s ease,background-color .2s ease}}
.settings-footer{display:flex;align-items:center;justify-content:center;gap:12px;margin:0 auto;padding:20px 24px 28px;color:#52684c;font-size:16px;font-weight:600}.settings-footer select{min-height:46px;padding:8px 34px 8px 14px;border:2px solid #b5c7a3;border-radius:14px;background:#f6faed;color:#304c2b;font:inherit;cursor:pointer}.settings-footer select:focus-visible{outline:3px solid #967549;outline-offset:4px}
.header{gap:20px;flex-wrap:wrap}.nav-button{display:inline-flex;align-items:center;justify-content:center;gap:12px;min-height:48px;padding:9px 20px;border:2px solid #527248;border-radius:20px;background:#d9eabd;color:#304c2b;text-decoration:none;font-size:18px;font-weight:800;white-space:nowrap;box-shadow:0 3px 0 #527248}.nav-button span{font-size:25px;line-height:1}.nav-button:hover{background:#cfe3ae}.nav-button:active{transform:translateY(2px);box-shadow:0 1px 0 #527248}.addition-problem{display:grid;grid-template-columns:.85em repeat(2,minmax(48px,1ch));column-gap:.15em;row-gap:.05em;width:max-content;font-family:ui-monospace,"SFMono-Regular",Consolas,monospace;font-size:clamp(44px,7vw,64px);font-variant-numeric:tabular-nums;font-weight:800;line-height:1.25;letter-spacing:0;margin:10px auto 30px;text-align:right}.addition-problem #first-number{grid-column:2 / 4;grid-row:1}.addition-problem .problem-symbol{grid-column:1;grid-row:2;color:#71816a;text-align:center}.addition-problem #second-number{grid-column:2 / 4;grid-row:2}.addition-problem #first-number,.addition-problem #second-number{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));column-gap:.15em;text-align:center}.addition-problem .problem-answer{display:grid;grid-template-columns:.85em repeat(2,minmax(48px,1ch));column-gap:.15em;grid-column:1 / -1;grid-row:3;border-top:4px solid #527248;margin-top:.06em;padding-top:.12em;color:#3f6653}.problem-actions{display:flex;justify-content:center;margin-top:28px;padding-bottom:5px}@media(max-width:760px){.header{gap:16px}.nav-button{font-size:16px;min-height:46px;padding:8px 16px}}

.answer-digit{width:100%;min-width:0;min-height:1.35em;border:2px solid #91aa7f;border-radius:12px;background:#f6faed;color:#304c2b;font:inherit;line-height:1.2;text-align:center;padding:0;caret-color:#304c2b}#answer-tens{grid-column:2}#answer-ones{grid-column:3}
.answer-feedback{min-height:1.6em;margin:22px 0 0;text-align:center;font-size:22px;font-weight:700;color:#3f6653}.answer-feedback[data-result="incorrect"]{color:#995541}.answer-digit[aria-invalid="true"]{border-color:#ad6552;background:#fff2ec}.problem-actions{gap:20px;flex-wrap:wrap;margin-top:12px}.problem-actions [hidden]{display:none}.reset:disabled{opacity:.55;cursor:default;transform:none;box-shadow:0 5px 0 #527248}.confetti-layer{position:fixed;inset:0;z-index:10;overflow:hidden;pointer-events:none}.confetti-piece{position:absolute;top:15%;left:50%;width:10px;height:16px;border-radius:3px;animation:confetti-fall 1350ms ease-out both}@keyframes confetti-fall{0%{opacity:1;transform:translate3d(0,0,0) rotate(0)}100%{opacity:0;transform:translate3d(var(--x),var(--y),0) rotate(var(--spin))}}@media(prefers-reduced-motion:reduce){.confetti-piece{display:none;animation:none}}
.practice-nav{display:flex;align-items:center;flex-wrap:wrap;gap:12px;margin-left:auto}@media(max-width:760px){.practice-nav{width:100%;margin-left:0}.practice-nav .nav-button{flex:1}}
/* Compact practice pages keep the problem and abacus together. */
body[data-operation] .header{padding-top:14px;padding-bottom:14px}body[data-operation] main{padding-top:14px;padding-bottom:14px}body[data-operation] .abacus-panel{padding:18px 28px 14px}body[data-operation] .addition-problem{font-size:clamp(40px,6vh,56px);margin:0 auto 12px}.abacus-controls{justify-content:space-between;gap:12px}.answer-actions{display:flex;align-items:center}.answer-actions [hidden]{display:none}body[data-operation] .abacus-controls .reset{min-height:52px;font-size:18px;padding:7px 16px;border-radius:21px}body[data-operation] .frame{margin-top:14px;padding-top:16px;padding-bottom:16px}body[data-operation] .row{height:72px}body[data-operation] .bead{top:15px}body[data-operation] .row:before{top:34px}body[data-operation] .answer-feedback{min-height:28px;font-size:20px;line-height:1.4;margin:10px 0 0}@media(max-width:760px){body[data-operation] .header{padding:10px 16px;gap:8px}body[data-operation] main{padding:8px 12px}body[data-operation] .abacus-panel{padding:12px}body[data-operation] .abacus-controls .reset{min-height:48px;font-size:16px;gap:6px;padding:7px 10px}.abacus-controls .reset-icon{width:26px;height:26px}.abacus-controls .reset-icon svg{width:19px;height:19px}body[data-operation] .addition-problem{margin-bottom:10px}body[data-operation] .frame{margin-top:12px}body[data-operation] .answer-feedback{font-size:18px;min-height:26px;margin-top:8px}}
@media(max-width:380px){.abacus-controls{gap:8px}body[data-operation] .abacus-controls .reset{font-size:14px;padding:7px 8px}}