.arithmetic-dialog{width:min(900px,calc(100vw - 24px));max-width:none;max-height:92vh;margin:auto;border:1px solid #a8bdae;border-radius:20px;padding:28px;background:var(--paper,#fffefb);color:var(--ink,#21352c);font:19px/1.65 'Segoe UI',Arial,sans-serif;overflow:auto}.arithmetic-dialog::backdrop{background:#153325b0}.arithmetic-top{display:flex;align-items:flex-start;justify-content:space-between;gap:20px}.arithmetic-top h2{font-size:30px;line-height:1.2;margin:0 0 15px}.arithmetic-top .eyebrow{margin-bottom:10px}.arithmetic-top>button{flex-shrink:0;font-size:15px}.arithmetic-return-note{font-size:16px;color:var(--muted,#607368);margin:4px 0 24px}.arithmetic-settings{display:grid;grid-template-columns:1.5fr 1fr;gap:18px;margin:25px 0}.arithmetic-settings label{display:flex;flex-direction:column;font-size:16px;gap:8px}.arithmetic-settings select{width:100%;min-width:0}.arithmetic-exercise{border-top:1px solid #dce5dc;padding-top:25px}.arithmetic-exercise>h3{font-size:27px;line-height:1.6;margin:0 0 25px}.arithmetic-form{margin:20px 0}.arithmetic-form label{display:block;margin-bottom:12px;line-height:1.7}.arithmetic-form label span{display:block;color:var(--muted,#607368);font-size:15px}.arithmetic-form>div{display:flex;gap:14px;flex-wrap:wrap}.arithmetic-form input{width:200px;max-width:100%;font-size:24px;line-height:1.3}.arithmetic-actions,.arithmetic-bottom{display:flex;flex-wrap:wrap;gap:12px;margin:24px 0}.arithmetic-bottom{border-top:1px solid #dce5dc;padding-top:24px;justify-content:space-between}.arithmetic-hint{padding:18px 22px;border-left:3px solid #a9ba8a;background:#f4f2e6;border-radius:0 10px 10px 0;line-height:1.8;margin:22px 0}.arithmetic-hint p:last-child{margin-bottom:0}.arithmetic-guided{border:1px solid #dce5dc;border-radius:14px;padding:24px;margin:25px 0}.arithmetic-completed{border-top:1px solid #dce5dc;padding:18px 0;color:#496351}.arithmetic-completed>span{font-size:13px;letter-spacing:.08em;text-transform:uppercase}.arithmetic-completed p{margin:8px 0 0}.arithmetic-current{border-left:3px solid #216747;padding-left:20px;margin-left:-20px;margin-top:20px}.arithmetic-current>p{color:#216747;font-size:15px}.arithmetic-feedback:empty{display:none}.arithmetic-feedback{background:#edf4ec;padding:16px 20px;border-radius:10px;margin:22px 0}.arithmetic-feedback.error{background:#fff2e5;color:#814522}.arithmetic-result{padding:22px;background:#eaf4e8;border-radius:12px}.arithmetic-result>strong{font-size:28px}.arithmetic-result p{margin:10px 0 22px}.arithmetic-stats{font-size:16px;color:var(--muted,#607368);padding:12px 0}.arithmetic-stats p{margin:14px 0}.arithmetic-storage{background:#fff1dd;padding:15px 20px;border-radius:8px;font-size:15px}.arithmetic-model{margin:20px 0 30px;padding:20px;background:#f2f7f0;border-radius:12px;overflow:auto}.arithmetic-model>p{font-size:15px;color:var(--muted,#607368);margin:15px 0 0}.arithmetic-column{border-collapse:collapse;font:28px/1.6 ui-monospace,SFMono-Regular,Consolas,monospace;margin:auto}.arithmetic-column td,.arithmetic-column th{min-width:1.35em;text-align:center;padding:3px}.arithmetic-column th{font-size:20px;font-weight:400}.arithmetic-column .arithmetic-line:first-of-type{border-top:2px solid #365f45}.arithmetic-column tr:nth-child(3){border-top:2px solid #365f45}.arithmetic-unknown{color:#a9bcad}.arithmetic-division{display:grid;grid-template-columns:auto auto;justify-content:center;font:30px/1.5 ui-monospace,SFMono-Regular,Consolas,monospace;gap:0}.arithmetic-division>span:first-child{padding-right:20px}.arithmetic-division>span:nth-child(2){border-left:2px solid #365f45;border-bottom:2px solid #365f45;padding:0 15px}.arithmetic-division>strong{border-left:2px solid #365f45;padding:5px 15px;font-weight:500;white-space:nowrap;color:#216747}.arithmetic-division-rows{margin:20px auto 0;max-width:380px;font-variant-numeric:tabular-nums}.arithmetic-division-rows p{margin:8px 0}.arithmetic-groups{display:flex;flex-wrap:wrap;gap:12px;margin:20px 0}.arithmetic-groups>span{display:grid;grid-template-columns:repeat(3,12px);gap:5px;background:#e5efdf;border:1px solid #b0c7af;border-radius:10px;padding:10px}.arithmetic-groups i{height:12px;width:12px;background:#39815b;border-radius:50%}@media(max-width:600px){.arithmetic-dialog{padding:21px 16px;width:calc(100vw - 14px);max-height:96vh;border-radius:14px}.arithmetic-top{display:block}.arithmetic-top>button{width:100%;margin:4px 0 12px}.arithmetic-top h2{font-size:27px}.arithmetic-settings{grid-template-columns:1fr}.arithmetic-exercise>h3{font-size:24px}.arithmetic-guided{padding:20px 14px}.arithmetic-current{margin-left:-10px;padding-left:10px}.arithmetic-form input{width:160px}.arithmetic-actions>button{flex:1;min-width:135px}.arithmetic-model{padding:16px 10px}.arithmetic-column{font-size:25px}.arithmetic-division{font-size:27px}.arithmetic-bottom>button{width:100%}}@media print{.arithmetic-dialog{display:none!important}}

.arithmetic-exchanged{color:#216747;background:#dcebd7;font-weight:700;border-radius:5px}