:root{color-scheme:light;--ink:#182b43;--muted:#5e6b7b;--blue:#173f7b;--paper:#f7f8fa;--line:#dbe1e9;--if:#dce9fa;--id:#fcdfad;--ex:#d9eee9;--mem:#e8e0f4;--wb:#f7dce2;font-family:"Segoe UI",Arial,sans-serif;color:var(--ink);background:var(--paper)}
*{box-sizing:border-box}body{margin:0}button,input,select{font:inherit}button,select{min-height:40px;border:1px solid #bdc8d7;border-radius:6px;background:#fff;color:var(--ink)}button{padding:8px 14px;cursor:pointer;font-weight:600}button:hover{border-color:var(--blue);background:#f1f5fc}button.primary{background:var(--blue);border-color:var(--blue);color:#fff}button.primary:hover{background:#24518f}button:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #668fd0;outline-offset:3px}button:disabled{opacity:.5;cursor:default}code,kbd,.cell,.grid-table{font-family:Consolas,"Cascadia Code",monospace}header{height:69px;border-bottom:1px solid var(--line);background:#fff;padding:0 3.5vw;display:flex;align-items:center;justify-content:space-between;gap:20px}.wordmark{font-weight:700;display:flex;align-items:center;gap:10px;white-space:nowrap}.mark{background:var(--blue);color:#fff;padding:7px 9px;border-radius:5px;font-family:Consolas,monospace}.course{font-weight:400;color:var(--muted);font-size:13px;padding-left:12px;border-left:1px solid var(--line)}.saved{font-size:12px;color:var(--muted)}main{max-width:1600px;margin:auto;padding:38px 3.5vw}.intro{display:flex;justify-content:space-between;align-items:flex-end;gap:25px;margin-bottom:28px}h1{font-size:clamp(28px,3vw,40px);letter-spacing:-1.2px;margin:6px 0 8px;font-weight:650}.intro p{color:var(--muted);margin:0}.intro .eyebrow{font-size:11px;font-weight:700;letter-spacing:1.3px;color:var(--blue)}.question-controls{display:flex;align-items:end;flex-wrap:wrap;gap:9px}.question-controls label{display:flex;flex-direction:column;font-size:11px;gap:5px;color:var(--muted)}select{padding:6px 28px 6px 10px;min-width:70px}.question-controls .primary{min-width:145px;display:flex;justify-content:space-between;gap:14px}.program-section{background:#fff;border:1px solid var(--line);border-top:3px solid var(--blue);border-radius:6px;padding:17px 20px;margin-bottom:23px}.program-heading{display:flex;align-items:center;justify-content:space-between;gap:12px}.program-heading h2{font-size:14px;margin:0}.program-heading span{color:var(--muted);font-size:12px}.program{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));grid-auto-flow:column;grid-template-rows:repeat(var(--program-rows,3),auto);gap:9px 25px;list-style:none;padding:15px 0 0;margin:0}.program li{display:flex;align-items:baseline;gap:12px;font-size:14px;white-space:nowrap}.instruction-number{font:12px Consolas,monospace;color:var(--muted);width:25px;flex-shrink:0}.op{font-weight:700;color:var(--blue)}.stage-key{display:flex;flex-wrap:wrap;gap:12px 24px;margin-bottom:15px;font-size:12px}.stage-key>span{display:flex;align-items:center;gap:7px}.stage-key b{font:700 12px Consolas,monospace;padding:5px 7px;border-radius:4px}.stage-if{background:var(--if)}.stage-id{background:var(--id)}.stage-ex{background:var(--ex)}.stage-mem{background:var(--mem)}.stage-wb{background:var(--wb)}.hold-rule{font-size:13px;line-height:1.6;border-left:3px solid #d39d3b;padding:9px 13px;background:#fff7e8}.rules{margin:13px 0 23px;font-size:13px;line-height:1.65}.rules summary{cursor:pointer;width:fit-content;font-weight:600;color:var(--blue)}.rules-body{max-width:980px;padding:0 16px}.entry-help{font-size:12px;line-height:1.8;color:var(--muted);max-width:1050px;margin:0 0 15px}kbd{background:#fff;border:1px solid var(--line);border-bottom:2px solid #c4ccd8;padding:1px 5px;border-radius:3px;color:var(--ink)}.grid-section{background:#fff;border:1px solid var(--line);border-radius:7px;margin-bottom:26px;overflow:hidden}.grid-heading{padding:18px 20px;display:flex;align-items:center;justify-content:space-between;gap:15px}.grid-heading h2{font-size:19px;letter-spacing:-.3px;margin:0 0 5px}.grid-heading p{font-size:12px;color:var(--muted);margin:0;line-height:1.6}.grid-number{display:inline-flex;align-items:center;justify-content:center;background:#edf2fa;color:var(--blue);width:25px;height:25px;margin-right:7px;font-size:13px;border-radius:50%}.grid-actions{display:flex;flex-wrap:wrap;gap:8px;flex-shrink:0}.grid-actions button{font-size:12px;min-height:36px}.scroll-area{overflow:auto;max-height:610px;border-block:1px solid var(--line);overscroll-behavior-x:contain;scrollbar-color:#b1bdcd #edf0f4;scrollbar-width:thin}.scroll-area:focus-visible{outline:3px solid #668fd0;outline-offset:-3px}.grid-table{border-collapse:separate;border-spacing:0;font-size:12px;table-layout:fixed;width:max-content;min-width:100%}.grid-table th,.grid-table td{border-right:1px solid var(--line);border-bottom:1px solid var(--line);height:42px;width:43px;min-width:43px;max-width:43px;padding:0;text-align:center}.grid-table tr:last-child>*{border-bottom:0}.grid-table th:last-child,.grid-table td:last-child{border-right:0}.grid-table thead th{position:sticky;top:0;z-index:3;height:34px;background:#f0f3f7;color:#63738a;font-weight:500}.grid-table .row-label{position:sticky;left:0;width:258px;min-width:258px;max-width:258px;background:#fff;z-index:2;text-align:left;padding:0 12px;white-space:nowrap;font-weight:400;box-shadow:2px 0 3px #182b4309}.row-label .row-id{color:#6b798b;margin-right:12px}.grid-table thead .row-label{z-index:4;background:#f0f3f7;color:var(--muted);font:11px "Segoe UI",sans-serif}.cell{display:block;width:100%;height:100%;min-width:0;text-align:center;padding:0;border:0;border-radius:0;background:transparent;color:var(--ink);text-transform:uppercase;font-size:12px;font-weight:600;outline:none}.cell:hover:not(:disabled){box-shadow:inset 0 0 0 1px #a5b8d5}.cell:focus{box-shadow:inset 0 0 0 2px var(--blue);background:#edf3ff}.cell[aria-invalid=true]{box-shadow:inset 0 0 0 2px #b83939}.cell:disabled{color:var(--ink);opacity:1;-webkit-text-fill-color:var(--ink)}.given{color:#56708c;font-size:10px;margin-left:7px;font-family:"Segoe UI",sans-serif}.grid-table td[data-stage=IF]{background:var(--if)}.grid-table td[data-stage=ID]{background:var(--id)}.grid-table td[data-stage=EX]{background:var(--ex)}.grid-table td[data-stage=MEM]{background:var(--mem)}.grid-table td[data-stage=WB]{background:var(--wb)}.grid-table td.hold{background-image:repeating-linear-gradient(135deg,transparent,transparent 6px,#7357240d 6px,#7357240d 8px)}.grid-footer{padding:12px 20px;font-size:12px;line-height:1.7;min-height:48px;display:flex;flex-direction:column;gap:6px}.feedback{margin:0;color:var(--muted)}.feedback.error{color:#9b3333}.feedback.success{color:#17694b}.cell-note{margin:0;color:#425b7c}.solution-summary{font-weight:650;color:var(--blue);margin:0}.storage-note{color:#9b3333;font-size:12px}footer{border-top:1px solid var(--line);padding:20px 3.5vw;display:flex;justify-content:space-between;gap:15px;font-size:11px;color:var(--muted)}footer span{font-family:Consolas,monospace}dialog{border:1px solid var(--line);border-radius:10px;padding:25px;max-width:430px;color:var(--ink)}dialog::backdrop{background:#182b4360}dialog h2{margin-top:0;font-size:21px}dialog p{font-size:14px;line-height:1.6}.dialog-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:25px}
@media(min-width:1700px){main{padding-inline:30px}}@media(max-width:1050px){.intro{align-items:flex-start;flex-direction:column}.program{grid-template-columns:repeat(2,minmax(0,1fr));grid-template-rows:repeat(var(--program-rows-mobile,5),auto)}.grid-heading{align-items:flex-start;flex-direction:column}.stage-key{gap:10px 18px}}@media(max-width:620px){header{padding-inline:16px;height:61px}.course{display:none}.saved{max-width:125px;font-size:10px;text-align:right}main{padding:25px 12px}.intro{margin-bottom:20px}.intro p:not(.eyebrow){font-size:14px}.program-section{padding:14px}.program-heading{align-items:flex-start;flex-direction:column;gap:5px}.program{display:flex;flex-direction:column;gap:8px}.program li{font-size:13px}.stage-key{font-size:10px;gap:8px 13px}.stage-key b{font-size:10px}.grid-heading{padding:15px 12px}.grid-heading h2{font-size:17px}.grid-actions{width:100%}.grid-actions button{flex:1;padding-inline:8px;font-size:11px}.grid-table .row-label{width:215px;min-width:215px;max-width:215px;padding-inline:8px;font-size:11px}.row-label .row-id{margin-right:7px}.given{display:none}.grid-table td,.grid-table th{height:43px}.grid-footer{padding:12px}.question-controls{gap:7px}.question-controls button{font-size:12px}.question-controls .primary{min-width:130px}footer{padding:16px;flex-direction:column;gap:8px}.hold-rule{font-size:12px}}
[hidden]{display:none!important}.branch-operands{font-size:13px;line-height:1.7;margin:16px 0 0;padding-top:12px;border-top:1px solid var(--line);color:var(--blue)}.branch-answers{display:flex;flex-wrap:wrap;gap:15px 25px;align-items:center;padding:0 20px 16px;font-size:13px}.branch-answers label{display:flex;align-items:center;gap:8px}.branch-answers input{width:85px;padding:7px 9px;min-height:36px;border:1px solid #bdc8d7;border-radius:5px;color:var(--ink);background:#fff}.branch-answers input:focus{outline:2px solid var(--blue);outline-offset:1px}.branch-answers input[aria-invalid=true]{border:2px solid #b83939}.grid-table td.flushed{background:#f8d5d5;box-shadow:inset 0 -3px #b64343}.grid-table td.flushed .cell{color:#8e2222}.branch-answers input[readonly]{background:#edf3fa}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.notation{margin:12px 0 0}.dynamic-main .question-controls{max-width:100%}.dynamic-main .question-controls label{max-width:100%}.dynamic-main select{max-width:100%}.dynamic-main .grid-heading p{max-width:760px}.answer-table{border-collapse:separate;border-spacing:0;min-width:100%;font:12px Consolas,"Cascadia Code",monospace}.answer-table th,.answer-table td{border-right:1px solid var(--line);border-bottom:1px solid var(--line);text-align:center;min-width:96px;padding:5px 7px;height:49px}.answer-table tr:last-child>*{border-bottom:0}.answer-table tr>*:last-child{border-right:0}.answer-table thead th{position:sticky;top:0;background:#f0f3f7;z-index:2;font:600 11px "Segoe UI",sans-serif;color:var(--muted);white-space:nowrap}.answer-table tr>th:first-child{position:sticky;left:0;background:#fff;text-align:left;white-space:nowrap;z-index:1;min-width:150px;padding:10px 13px;font-weight:400}.answer-table thead th:first-child{z-index:3;background:#f0f3f7}.answer-input{width:100%;min-width:70px;max-width:180px;height:36px;padding:5px 7px;text-align:center;font:13px Consolas,monospace;color:var(--ink);background:#fff;border:1px solid #bdc8d7;border-radius:4px}.answer-input:focus{outline:2px solid var(--blue);outline-offset:1px}.answer-input[aria-invalid=true]{border:2px solid #b83939;background:#fff5f5}.answer-input[readonly]{background:#edf3fa;color:var(--blue)}.worked{padding:7px 13px;border-left:3px solid var(--blue);background:#f5f8fc;color:#425b7c}.worked p{margin:5px 0}.cycle-control{padding:6px 0 20px}.cycle-control label{display:flex;align-items:center;gap:12px;font-size:14px;font-weight:600}.cycle-control p{margin:10px 0 0}.cycle-control select{min-width:85px}.dynamic-main .grid-section{scroll-margin-top:15px}
@media(max-width:620px){.dynamic-main .answer-table tr>th:first-child{font-size:11px;max-width:190px;min-width:130px;white-space:normal;overflow-wrap:normal}.dynamic-main .answer-table th,.dynamic-main .answer-table td{min-width:94px;padding:5px}.dynamic-main .answer-table tr>th:first-child{padding:9px}.dynamic-main .question-controls{width:100%}.dynamic-main #practice{width:100%}.dynamic-main .question-controls label:first-child{width:100%}.answer-input{min-width:72px}.dynamic-main .grid-actions button{min-height:40px}.dynamic-main .branch-operands{font-size:12px}.dynamic-main .cycle-control p{font-size:12px}}
@media print{header,.intro,.stage-key,.hold-rule,.rules,.entry-help,.grid-actions,footer,.storage-note{display:none}.grid-section{break-inside:avoid}.scroll-area{overflow:visible;max-height:none}.grid-table{font-size:8px}.grid-table .row-label{min-width:170px;width:170px;max-width:170px}.grid-table th,.grid-table td{min-width:27px;width:27px;max-width:27px;height:30px}.cell{font-size:8px}main{padding:0}.grid-heading{padding:9px}.program-section{margin-bottom:10px}.program{font-size:11px}.grid-footer{padding:8px}}