:root{--paper:#f6f7f9;--white:#ffffff;--ink:#253047;--muted:#626a78;--line:#dce1e9;--action:#2d3b52;--soft:#edf0f5;--clay:#944a33;--clay-soft:#f6e9df;--nav:#eff1f5;--radius:14px;--focus:#9f422b;font-family:"Segoe UI",sans-serif;color:var(--ink);background:var(--paper);font-synthesis:none}
*{box-sizing:border-box}body{margin:0}button,input,textarea,select{font:inherit}button,a,input,textarea,select{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button:disabled{cursor:default;opacity:.55}button,a{touch-action:manipulation}a{color:var(--action);text-underline-offset:4px}button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible{outline:3px solid var(--focus);outline-offset:4px}::selection{background:#dbe6fb;color:#203552}input,textarea{caret-color:var(--action)}[hidden]{display:none!important}h1,h2,h3,p{margin:0}h1{font-size:clamp(28px,3vw,40px);font-weight:600;line-height:1.18;letter-spacing:-.035em;text-wrap:balance}h2{font-size:24px;line-height:1.3;font-weight:600;letter-spacing:-.025em}h3{font-size:18px;line-height:1.4;font-weight:600}p{line-height:1.65}small,.small{font-size:13px;line-height:1.5}.muted{color:var(--muted)}.demo-bar{background:#2b3446;color:#f1f3f8;padding:11px 28px;display:flex;align-items:center;justify-content:space-between;gap:16px;font-size:13px}.demo-bar>div{display:flex;gap:16px;flex-wrap:wrap}.demo-bar span{color:#d7deeb}.demo-button{background:transparent;color:inherit;border:1px solid #98a4ba;border-radius:7px;padding:8px 13px;white-space:nowrap}.screen-map{padding:25px 32px;background:var(--soft);border-bottom:1px solid var(--line)}.screen-map h2{font-size:20px;margin-bottom:10px}.map-groups{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:22px}.map-groups h3{margin-bottom:12px;font-size:15px}.map-groups button{display:block;background:none;border:0;color:var(--action);text-align:left;padding:7px 0;text-decoration:underline;text-underline-offset:4px}.shell{display:grid;grid-template-columns:214px minmax(0,1fr);min-height:calc(100vh - 58px)}.sidebar{background:var(--nav);padding:31px 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a.active{background:var(--action);color:#fff}.icon{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round;flex-shrink:0}.sidebar-foot{margin-top:auto;font-size:12px;color:var(--muted)}.sidebar-foot a{display:inline-block;margin-top:13px}.workspace{min-width:0}.topbar{height:79px;display:flex;justify-content:space-between;align-items:center;gap:16px;border-bottom:1px solid var(--line);padding:0 45px;font-size:14px}.topbar .quiet{font-size:13px}.content{max-width:1160px;margin:auto;padding:44px 45px 56px}.child-content{max-width:1030px}.page-heading{margin-bottom:30px;display:flex;justify-content:space-between;align-items:flex-start;gap:16px}.page-heading p{margin-top:13px;color:var(--muted);max-width:58ch}.button{display:inline-flex;align-items:center;justify-content:center;gap:9px;min-height:46px;padding:11px 20px;border-radius:8px;border:1px solid var(--line);background:var(--white);color:var(--ink);text-decoration:none;font-weight:600;font-size:15px;line-height:1.4;text-align:center}.button:hover{background:#e7ebf2}.button.primary{background:var(--action);color:#fff;border-color:var(--action)}.button.primary:hover{background:#1e293c}.button.soft{background:var(--soft);border-color:transparent;color:#304563}.button.quiet{background:none;border-color:transparent;font-weight:400;padding:10px 8px;color:var(--muted)}.button.danger{color:var(--clay)}.button.small{font-size:13px;min-height:40px;padding:8px 14px}.actions{display:flex;flex-wrap:wrap;gap:12px;align-items:center}.actions.spaced{margin-top:27px}.hero-lesson{display:grid;grid-template-columns:minmax(0,1fr) 235px;background:var(--soft);border-radius:var(--radius);overflow:hidden;margin-bottom:32px}.hero-copy{padding:32px}.hero-copy h2{font-size:30px;max-width:17ch;margin-top:17px}.hero-copy p{max-width:42ch;margin:15px 0 24px}.hero-copy 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9px;border-radius:5px;background:var(--soft);color:#2d496a;white-space:normal}.pill.neutral{background:#e9edf3;color:#526174}.pill.warm{background:var(--clay-soft);color:#79402e}.note{font-size:14px;color:var(--muted);line-height:1.65}.notice{padding:15px 19px;border-radius:9px;background:var(--soft);line-height:1.6;font-size:14px}.notice.warm{background:var(--clay-soft);color:#713e2d}.task-layout{display:grid;grid-template-columns:minmax(0,1fr) 215px;gap:32px}.task-sheet{background:var(--white);border:1px solid var(--line);border-radius:var(--radius);padding:30px}.lesson-steps{display:flex;gap:6px;margin-bottom:30px;list-style:none;padding:0}.lesson-steps li{flex:1;border-top:3px solid #dce1e9;padding-top:10px;font-size:12px;color:var(--muted)}.lesson-steps li.current{border-color:var(--action);color:var(--ink);font-weight:600}.lesson-steps li.done{border-color:#9aa9bf}.task-sheet h1{font-size:29px;line-height:1.25;margin-bottom:23px}.task-text{font-size:18px;line-height:1.75;margin-bottom:23px;max-width:60ch}.task-text p+p{margin-top:11px}.question{font-weight:600;margin-top:22px!important}.answer-block{margin:26px 0 0}.answer-label{font-size:14px;font-weight:600;display:block;margin-bottom:9px}.input-row{display:flex;gap:12px;align-items:center;flex-wrap:wrap}.input{width:140px;max-width:100%;padding:12px 14px;border:1px solid #929db1;background:var(--white);border-radius:8px;min-height:48px;font-size:18px;color:var(--ink)}.input.wide{width:100%}.answer-label span{font-weight:400;color:var(--muted)}.packet-inputs{display:flex;gap:20px;flex-wrap:wrap}.packet-inputs .input{width:100px}.feedback{padding:16px 18px;background:var(--soft);border-radius:9px;line-height:1.6;margin-top:22px}.feedback.error{background:var(--clay-soft);color:#713e2d}.feedback strong{display:block;margin-bottom:5px}.task-aside h2{font-size:17px;margin:4px 0 13px}.task-aside p{font-size:14px;color:var(--muted);margin-bottom:15px}.task-aside .button{width:100%;margin-bottom:9px;font-size:14px}.task-aside .aside-group+.aside-group{border-top:1px solid var(--line);margin-top:22px;padding-top:22px}.hint-area{border-top:1px solid var(--line);margin-top:25px;padding-top:23px}.hint-area h2{font-size:18px;margin-bottom:12px}.hint-area p{line-height:1.7}.hint-area .actions{margin-top:18px}.math-table{width:100%;border-collapse:collapse;margin:19px 0;font-variant-numeric:tabular-nums;font-size:15px}.math-table th,.math-table td{padding:13px 10px;text-align:left;border-bottom:1px solid var(--line);overflow-wrap:anywhere}.math-table th{font-size:13px;color:var(--muted);font-weight:500}.math-table td:first-child,.math-table th:first-child{padding-left:0}.theory-layout{display:grid;grid-template-columns:180px minmax(0,1fr);gap:35px}.categories{display:flex;flex-direction:column;gap:7px;align-items:flex-start}.categories button{padding:10px 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.go{margin-top:30px;display:flex;justify-content:space-between;font-weight:600}.parent-entry{display:flex;justify-content:space-between;align-items:center;border-top:1px solid var(--line);margin:30px 0;padding-top:24px;gap:18px}.entry-footer{font-size:12px;color:var(--muted);padding:20px 0 30px}.finish{max-width:670px;margin:auto}.finish h1{margin:22px 0 18px}.finish-symbol{width:70px;height:70px;border-radius:50%;display:grid;place-items:center;background:var(--soft);color:var(--action)}.finish-symbol .icon{width:34px;height:34px}.finish .result-list{margin:25px 0}.result-line{display:grid;grid-template-columns:120px minmax(0,1fr);gap:20px;padding:19px 0;border-bottom:1px solid var(--line);font-size:15px;line-height:1.6}.result-line>span{color:var(--muted)}.parent-children{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin:28px 0 34px}.child-summary{padding:25px;border:1px solid var(--line);background:var(--white);border-radius:var(--radius)}.child-summary .account{margin-bottom:24px}.child-summary h3{font-size:20px}.child-summary p{margin:12px 0 18px}.child-summary .button{margin-top:20px}.child-summary dl{margin:20px 0 0;font-size:14px}.child-summary dl>div{display:flex;justify-content:space-between;gap:15px;padding:10px 0;border-top:1px solid var(--line)}dt{color:var(--muted)}dd{margin:0;font-weight:500}.section-title{font-size:23px;margin:30px 0 17px}.parent-note{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:20px;padding:21px 0;border-bottom:1px solid var(--line);align-items:center}.parent-note h3{margin-bottom:6px}.parent-note p{max-width:65ch;font-size:14px;color:var(--muted)}.data-table{width:100%;border-collapse:collapse;font-size:14px}.data-table th{text-align:left;color:var(--muted);font-size:12px;font-weight:500;padding:13px 12px;border-bottom:1px solid var(--line)}.data-table td{padding:18px 12px;border-bottom:1px solid var(--line);vertical-align:top;line-height:1.6}.data-table td:first-child,.data-table th:first-child{padding-left:0}.data-table small{display:block;color:var(--muted)}.data-table td:last-child{min-width:125px}.timeline{list-style:none;margin:25px 0;padding:0}.timeline li{display:grid;grid-template-columns:88px minmax(0,1fr);gap:20px;padding:20px 0;border-bottom:1px solid var(--line)}.timeline .time{font-size:13px;color:var(--muted)}.timeline h3{margin-bottom:8px}.timeline p{font-size:15px}.quote{margin:15px 0 0;font-size:16px;font-style:normal;padding:17px 21px;background:var(--white);border:1px solid var(--line);border-radius:9px}.settings-row{display:flex;justify-content:space-between;gap:24px;padding:24px 0;border-bottom:1px solid var(--line);align-items:center}.settings-row p{font-size:14px;color:var(--muted);margin-top:6px}.settings-row select{padding:11px;border:1px solid var(--line);border-radius:7px;background:var(--white);color:var(--ink);max-width:100%}.check{display:flex;align-items:flex-start;gap:12px;line-height:1.6}.check input{accent-color:var(--action);width:20px;height:20px;flex-shrink:0;margin-top:3px}.empty{text-align:center;padding:50px 20px}.empty h2{margin-bottom:13px}.empty p{color:var(--muted)}.mobile-account{display:none}.save-status{font-size:13px;color:var(--action);margin-top:16px}.demo-tools{border-top:1px solid var(--line);padding-top:20px;margin-top:36px;color:var(--muted)}.demo-tools summary{font-size:12px;cursor:pointer}.demo-tools .actions{margin-top:12px}.offline-bar{margin-bottom:25px;background:var(--clay-soft);padding:15px 19px;border-radius:9px;display:flex;align-items:center;justify-content:space-between;gap:16px;font-size:14px}.progress-track{height:5px;background:#e0e5ee;border-radius:3px;overflow:hidden;margin-top:12px}.progress-fill{background:var(--action);height:100%;width:45%}.parent-tabs{display:flex;gap:10px;margin:26px 0;flex-wrap:wrap}.parent-tabs a{min-height:42px;padding:9px 15px;color:var(--muted);text-decoration:none;border-bottom:2px solid transparent}.parent-tabs a.active{border-color:var(--action);color:var(--action);font-weight:600}
@media(min-width:1500px){.content{padding-top:55px}.task-sheet{padding:38px}}
@media(max-width:1080px){.shell{grid-template-columns:178px minmax(0,1fr)}.sidebar{padding:27px 15px}.brand{font-size:18px}.topbar{padding:0 28px}.content{padding:32px 28px 45px}.task-layout{grid-template-columns:minmax(0,1fr)}.task-aside{display:grid;grid-template-columns:1fr 1fr;gap:25px}.task-aside .aside-group+.aside-group{border:0;padding:0;margin:0}.hero-lesson{grid-template-columns:minmax(0,1fr) 170px}.hero-copy{padding:26px}.home-grid{gap:23px}}
@media(max-width:760px){.demo-bar{padding:10px 16px;font-size:11px;gap:12px}.demo-bar>div{gap:3px;flex-direction:column}.demo-bar span{max-width:30ch}.demo-button{padding:9px;font-size:11px}.screen-map{padding:22px 18px}.map-groups{grid-template-columns:1fr;gap:16px}.shell{display:block;min-height:0}.sidebar{padding:18px 19px 0;gap:17px}.sidebar>.account,.sidebar-foot{display:none}.sidebar .nav{flex-direction:row;gap:5px;padding-bottom:13px;overflow:auto}.nav a{white-space:nowrap;font-size:13px;padding:11px 12px}.nav .icon{width:17px;height:17px}.brand{font-size:20px}.topbar{padding:0 20px;height:57px;font-size:12px;gap:8px}.topbar .button{font-size:12px;min-height:40px;padding:7px 0}.content{padding:28px 20px 42px}.page-heading{margin-bottom:25px}.page-heading p{font-size:15px}.page-heading .button{font-size:13px;padding:8px 12px}.hero-lesson{grid-template-columns:minmax(0,1fr) 100px}.hero-copy{padding:24px 20px}.hero-copy h2{font-size:25px;margin-top:14px}.hero-copy .meta{font-size:12px;gap:9px;flex-wrap:wrap}.hero-copy p{font-size:15px;margin:14px 0 22px}.hero-art{padding:12px 9px}.hero-art span{font-size:11px;text-align:center}.home-grid{grid-template-columns:1fr;gap:28px}.task-sheet{padding:23px 20px}.task-sheet h1{font-size:25px}.task-text{font-size:17px}.lesson-steps{margin-bottom:23px}.lesson-steps li{font-size:11px}.task-layout{gap:27px}.task-aside{gap:18px}.task-aside p{font-size:13px}.task-aside .button{padding:11px 8px;font-size:13px}.theory-layout{grid-template-columns:1fr;gap:8px}.categories{flex-direction:row;flex-wrap:wrap;margin-bottom:13px;gap:0}.categories button{padding:10px;font-size:13px}.theory-article>p{font-size:17px}.theory-example{padding:21px}.math-table{font-size:13px}.math-table td,.math-table th{padding:11px 6px}.math-table th{font-size:12px}.entry{margin:27px auto;padding:0 22px}.entry .brand{margin-bottom:36px}.entry h1{font-size:36px}.entry>p{font-size:16px;margin-bottom:25px}.entry-roles{grid-template-columns:1fr;gap:16px}.role-card{padding:23px}.role-card .avatar{float:right;margin:0}.role-card .go{margin-top:23px}.parent-entry{align-items:flex-start}.parent-entry .button{font-size:13px}.parent-children{grid-template-columns:1fr;gap:18px}.child-summary{padding:24px}.parent-note{grid-template-columns:1fr;gap:13px}.parent-note .button{justify-self:start}.result-line{grid-template-columns:1fr;gap:5px}.timeline li{grid-template-columns:1fr;gap:8px}.settings-row{flex-direction:column;align-items:stretch;gap:15px}.data-table,.data-table tbody{display:block}.data-table thead{display:none}.data-table tr{display:block;border-bottom:1px solid var(--line);padding:17px 0}.data-table td{display:block;border:0;padding:5px 0}.data-table td::before{content:attr(data-label);display:block;font-size:12px;color:var(--muted)}.data-table td:first-child{font-size:17px;font-weight:600}.offline-bar{flex-direction:column;align-items:flex-start}.parent-tabs{gap:3px}.parent-tabs a{font-size:13px;padding:9px 10px}.finish h1{font-size:32px}}
@media(max-width:370px){.hero-lesson{display:block}.hero-art{display:none}.nav a{gap:6px;padding:10px 9px}.task-sheet{padding:20px 16px}.content{padding-left:16px;padding-right:16px}.task-aside{grid-template-columns:1fr}.task-aside .aside-group+.aside-group{padding-top:15px;border-top:1px solid var(--line)}.task-aside .button{width:auto;min-width:150px}.button{padding:11px 15px}.packet-inputs{gap:13px}}
@media(prefers-reduced-motion:no-preference){.button,.nav a,.role-card{transition:background-color .15s ease-out}}

@media(max-width:370px){.sidebar .nav{overflow:visible}.nav a{flex:1;justify-content:center;padding:10px 6px;font-size:12px}.nav .icon{display:none}}

/* Revision 2: neutral navigation; color belongs to the learning content. */
:root{--blue:#2459ad;--blue-soft:#eaf1ff;--orange:#98420b;--orange-soft:#fff0e0;--purple:#7042a0;--purple-soft:#f1eafa}
.ink-blue{color:var(--blue)!important}.ink-orange{color:var(--orange)!important}.ink-purple{color:var(--purple)!important}
.tone-blue{--tone:var(--blue);--wash:var(--blue-soft)}.tone-orange{--tone:var(--orange);--wash:var(--orange-soft)}.tone-purple{--tone:var(--purple);--wash:var(--purple-soft)}
.hero-lesson{background:var(--white);border:1px solid var(--line)}.brand-mark i{background:var(--blue)}.brand-mark i:nth-child(2){background:var(--purple)}.brand-mark i:last-child{background:#bf6824}.hero-art{background:#f0f3f8}.notice,.theory-example{background:var(--soft)}
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