:root{color-scheme:light;--paper:#fbf8f0;--ink:#353940;--muted:#676c71;--purple:#6864a0;--lilac:#e9e5f4;--sage:#dfeadd;--line:#dfdfd7;--white:#fffefb;font-family:"Microsoft YaHei","PingFang SC","Noto Sans CJK SC",sans-serif;color:var(--ink);background:var(--paper);font-synthesis:none}
*{box-sizing:border-box}body{margin:0}button,input,select,textarea{font:inherit}button{color:var(--ink);border:1px solid var(--line);background:var(--white);border-radius:10px;padding:10px 14px;cursor:pointer;line-height:1.35}button:hover:not(:disabled){border-color:var(--purple);background:#f4f1fb}button:disabled{opacity:.45;cursor:not-allowed}button.primary{background:var(--purple);border-color:var(--purple);color:white;font-weight:600}button.primary:hover{background:#555183}button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible,[tabindex]:focus-visible{outline:3px solid #a29dd2;outline-offset:3px}input,select,textarea{min-width:0;width:100%;border:1px solid #cecec8;border-radius:8px;background:#fffefc;color:var(--ink);padding:10px 11px;margin-top:7px}input[type=checkbox],input[type=radio]{width:19px;height:19px;margin:0;accent-color:var(--purple);flex-shrink:0}label{font-size:13px;display:block;line-height:1.5}label>span{color:var(--muted);font-size:11px}h1,h2,h3,p{margin:0}h1{font-family:"STKaiti","KaiTi","Microsoft YaHei",serif;font-size:34px;letter-spacing:1px;font-weight:600;line-height:1.4}h2{font-size:18px;font-weight:650}h3{font-size:15px;margin-bottom:10px}p{line-height:1.75}small{font-size:11px;color:var(--muted)}[hidden]{display:none!important}.topbar{height:88px;padding:0 4vw;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;background:#fffdf7}.brand{color:inherit;text-decoration:none;display:flex;align-items:center;gap:10px}.brand img{width:54px;height:54px}.brand>span{font-size:25px;font-weight:700;letter-spacing:4px}.brand small{display:block;font-size:10px;font-weight:400;letter-spacing:1px;margin-top:3px}.top-actions{display:flex;align-items:center;gap:12px;font-size:13px}.privacy-pill{color:#5b6d5e;padding-right:10px;font-size:12px}.privacy-pill:before{content:"";display:inline-block;width:7px;height:7px;background:#91a88c;border-radius:50%;margin-right:7px}main{max-width:1480px;padding:0 4vw;margin:auto}.intro{display:flex;justify-content:space-between;align-items:center;min-height:177px;padding:28px 10px 32px}.intro-note{color:var(--purple);font-size:12px;margin-bottom:8px}.intro h1+p{color:var(--muted);font-size:13px;margin-top:10px}.sample-stack{position:relative;width:200px;height:130px;flex-shrink:0}.sample-stack img{width:120px;position:absolute;right:65px;top:0;transform:rotate(-14deg)}.sample-stack img+img{right:0;top:18px;transform:rotate(17deg)}.sample-stack span{position:absolute;bottom:0;right:15px;color:#7e8072;font-size:11px;transform:rotate(-6deg)}.workspace{display:grid;grid-template-columns:370px minmax(0,1fr);gap:28px;align-items:start}.parameters{background:var(--white);border:1px solid var(--line);border-radius:18px;overflow:hidden}.input-section{padding:24px;border-bottom:1px solid var(--line)}.input-section:last-child{border:0}.section-heading{display:flex;justify-content:space-between;align-items:center;gap:8px;margin-bottom:16px}.section-heading>span{font-size:11px;color:var(--muted)}.pair{display:flex;gap:10px;align-items:center}.pair label{flex:1}.pair .times{padding-top:24px;color:#9b9d96}.pair input{font-size:21px;font-weight:600;letter-spacing:.3px}.text-button{padding:0;border:0;background:transparent;color:var(--purple);font-size:12px}.small-actions{margin:12px 0 15px}.advanced{font-size:12px;border-top:1px dashed var(--line);padding-top:12px}summary{cursor:pointer;line-height:1.6}summary span{color:var(--muted);margin-left:6px}.grid2{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:14px 0}.wide{grid-column:1/-1}.hint{font-size:11px;color:var(--muted);line-height:1.7}.effective{font-size:11px;color:#697961;background:#f0f5eb;padding:8px 10px;border-radius:6px;margin-top:13px}.library-section .section-heading{margin-bottom:8px}.style-card{margin-top:14px;border:1px solid var(--line);border-radius:12px;overflow:hidden;background:#fffefb}.style-card.selected{border-color:#b9b6d1}.style-top{display:flex;align-items:center;gap:10px;padding:12px}.style-top img{width:44px;height:44px}.style-select{display:flex;align-items:center;gap:9px;flex:1;cursor:pointer;min-width:0}.style-description{min-width:0}.style-description strong{font-size:13px;display:block;overflow-wrap:anywhere}.style-description small{display:block;line-height:1.5}.style-top>button{font-size:11px;padding:6px 8px}.style-counts{display:grid;grid-template-columns:1fr 1fr;gap:12px;padding:0 12px 12px}.style-counts label{font-size:11px}.style-counts input{padding:7px 9px;margin-top:4px}.style-more{display:flex;align-items:center;justify-content:space-between;background:#f6f5f0;padding:7px 12px;gap:8px;font-size:10px;color:var(--muted)}.style-more button{font-size:10px;padding:0;border:0;background:transparent}.style-more .actions{display:flex;gap:12px}.temporary{color:var(--purple);font-weight:500}.goal-options{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:16px 0 12px}.goal-options label{display:flex;align-items:center;gap:7px;background:#f5f3f9;padding:11px 9px;border-radius:9px;cursor:pointer}.goal-options strong{display:block;font-size:12px;color:var(--ink)}.goal-options small{display:block;font-size:10px}.calculate-row{display:flex;gap:8px;margin-top:18px}.calculate-row .primary{flex:1;padding:14px;font-size:15px}.limits{font-size:10px;color:var(--muted);margin-top:12px}.limits p{margin-top:8px}#computeStatus{font-size:12px;color:var(--purple);margin-top:10px}#notice{padding:12px 16px;margin-bottom:16px;background:#fff0de;border-left:4px solid #d4a456;border-radius:8px;font-size:13px}.results{min-width:0}.results-heading{display:flex;justify-content:space-between;gap:16px;align-items:center;margin:8px 0 18px}.results-heading p{font-size:12px;color:var(--muted);margin-top:6px}.results-heading button{font-size:12px;flex-shrink:0}.empty-paper{min-height:488px;border:1px solid var(--line);border-radius:18px;display:grid;place-items:center;text-align:center;background:var(--white);padding:40px}.empty-paper img{width:120px;opacity:.85}.empty-paper h3{margin-top:15px;font-size:20px}.empty-paper p{font-size:13px;color:var(--muted);max-width:320px;margin-top:10px}.paper{background:var(--white);border:1px solid var(--line);border-radius:18px;overflow:hidden}.plan-tabs{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:14px}.plan-tabs button{font-size:12px;text-align:left;min-width:124px}.plan-tabs button[aria-pressed=true]{background:var(--purple);border-color:var(--purple);color:#fff}.plan-tabs small{color:inherit;display:block;margin-top:5px;opacity:.9}.paper-top{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:20px 22px;border-bottom:1px dashed var(--line);font-size:12px}.status-tag{padding:5px 8px;border-radius:5px;background:var(--sage);color:#476044;font-size:11px}.status-tag.unproved{background:#efeaf8;color:#686096}.stale-banner{background:#fff0d9;padding:12px 18px;font-size:13px;color:#805724}.stale .diagram-wrap{opacity:.52}.stat-row{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;padding:20px 24px;background:#fffefb}.stat-row .number{display:block;font-size:25px;font-weight:600;line-height:1.6}.stat-row small{font-size:11px}.stat-row .note{font-size:10px;color:var(--muted);display:block}.diagram-toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:0 22px 10px;font-size:11px}.diagram-toolbar label{display:flex;align-items:center;gap:6px}.diagram-toolbar input{width:90px;margin:0;padding:0}.diagram-scroll{overflow:auto;background:#f7f6f0;border-top:1px solid #edede5;border-bottom:1px solid #edede5}.diagram-wrap{min-width:100%;padding:12px}.diagram-wrap svg{display:block;width:100%;min-height:240px;max-height:700px}.piece{cursor:pointer}.piece:hover{filter:brightness(.95)}.legend{display:flex;gap:18px;flex-wrap:wrap;padding:14px 22px;font-size:10px;color:var(--muted)}.legend span:before{content:"";display:inline-block;width:12px;height:9px;margin-right:6px;vertical-align:middle;border:1px solid #979b94}.legend .remaining:before{background:repeating-linear-gradient(45deg,#ddd 0,#ddd 1px,#f9f8ef 1px,#f9f8ef 4px)}.legend .margin:before{background:#efeae0}.piece-detail{padding:12px 22px;background:#f2eff8;font-size:12px}.style-results{display:grid;gap:0;padding:8px 22px}.style-result{display:flex;gap:12px;align-items:center;border-bottom:1px solid #efeee8;padding:12px 0}.style-result:last-child{border:0}.style-result img{width:43px;height:43px}.style-result .desc{flex:1;min-width:0;font-size:12px}.style-result strong{overflow-wrap:anywhere}.style-result small{display:block;margin-top:4px}.style-result .count{font-size:19px;white-space:nowrap}.result-bottom{padding:18px 22px;border-top:1px dashed var(--line);font-size:11px;color:var(--muted)}.result-bottom details{margin-top:12px}.leftover-list{display:flex;flex-wrap:wrap;gap:6px;margin-top:8px;max-height:180px;overflow:auto}.leftover-list span{padding:4px 7px;background:#f3f2e9;border-radius:4px}.animation{padding:20px 22px;background:#f6f4fa;border-top:1px solid var(--line)}.animation .heading{display:flex;align-items:center;gap:10px;justify-content:space-between}.animation .heading h3{margin:0}.animation p{font-size:12px;margin:12px 0;color:#57516e;min-height:42px}.play-controls{display:flex;gap:7px;flex-wrap:wrap}.play-controls button{font-size:11px;padding:8px 12px}.proof-text{margin-top:10px;overflow-wrap:anywhere}.error-text{color:#a33d46;font-size:12px;line-height:1.7;margin-top:12px}footer{display:flex;gap:30px;font-size:12px;color:#6d716b;padding:32px 5px 38px;line-height:1.8}footer span{font-size:11px}dialog{border:1px solid var(--line);border-radius:18px;background:var(--white);color:var(--ink);padding:26px;width:min(490px,calc(100% - 28px));max-height:90vh;overflow:auto;box-shadow:0 24px 100px #2b273333}dialog::backdrop{background:#30323b66}dialog>p{font-size:12px;margin:12px 0 18px}.dialog-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:18px}.dialog-head button{border:0;font-size:24px;padding:0 8px;background:transparent}.dialog-actions{display:flex;gap:10px;justify-content:flex-end;margin-top:20px}.check-label{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:16px}.check-label span{font-size:10px}form>label{margin:14px 0}hr{border:0;border-top:1px solid var(--line);margin:22px 0}textarea{resize:vertical;font-family:inherit;font-size:12px}
@media(min-width:1500px){main{padding:0 40px}}@media(max-width:1050px){main{padding:0 22px}.workspace{grid-template-columns:330px minmax(0,1fr);gap:18px}.input-section{padding:20px}.results-heading{align-items:flex-start;flex-direction:column}.intro h1{font-size:29px}.stat-row{padding:15px;gap:8px}.stat-row .number{font-size:22px}.sample-stack{width:145px;transform:scale(.85)}.privacy-pill{display:none}}
@media(max-width:760px){.topbar{height:73px;padding:0 18px}.brand img{width:42px;height:42px}.brand>span{font-size:21px}.brand small{font-size:9px}.top-actions{gap:7px}.top-actions button{padding:8px;font-size:11px}main{padding:0 16px}.intro{padding:25px 1px;min-height:145px}.intro h1{font-size:25px;letter-spacing:0}.intro-note{font-size:11px}.intro h1+p{font-size:11px;max-width:285px}.sample-stack{display:none}.workspace{display:flex;flex-direction:column;gap:25px}.parameters,.results{width:100%}.parameters{border-radius:15px}.input-section{padding:20px}.results-heading{flex-direction:row;align-items:center;margin-top:0}.results-heading button{font-size:10px;padding:9px}.results-heading p{max-width:210px;font-size:11px}.results-heading h2{font-size:17px}.empty-paper{min-height:290px}.paper-top{padding:15px}.stat-row{padding:15px}.stat-row .number{font-size:23px}.diagram-toolbar{padding:0 15px 10px}.diagram-wrap{padding:4px}.diagram-wrap svg{min-height:180px}.style-results{padding:5px 15px}.legend{padding:12px 15px;gap:12px}.animation{padding:18px 15px}.result-bottom{padding:16px 15px}.plan-tabs{gap:6px}.plan-tabs button{flex:1;min-width:95px;padding:9px;font-size:10px}.plan-tabs small{font-size:9px}footer{display:block;padding:27px 4px;font-size:11px}footer span{display:block;margin-top:7px;font-size:10px}.dialog-actions{flex-wrap:wrap}dialog{padding:21px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important}}
.diagram-scroll{max-height:620px}.diagram-wrap svg{height:auto;max-height:none}

/* TASK-003: keep the fabric ratio; only the drawing viewport scrolls. */
main{max-width:none;padding:0 clamp(18px,2.4vw,46px)}
.topbar{height:66px;padding:0 clamp(18px,2.4vw,46px)}
.brand img{width:42px;height:42px}.brand>span{font-size:23px}
.intro{min-height:0;padding:16px 2px 20px}.intro h1{font-size:26px}
.intro-note,.sample-stack{display:none}.intro h1+p{margin-top:4px}
.workspace{grid-template-columns:360px minmax(0,1fr);gap:22px}
.parameters{display:grid;gap:12px;border:0;background:none;overflow:visible}
.input-section,.input-section:last-child{padding:18px;background:var(--white);border:1px solid var(--line);border-radius:14px}
.section-heading{margin-bottom:12px}.small-actions{margin:8px 0}.grid2{margin:8px 0 12px}
.style-top{padding:10px}.style-card{margin-top:10px}.style-top img{width:36px;height:36px}
.quantity-controls{padding:0 12px 10px}.quantity-controls select{padding:7px 9px;margin:4px 0 8px}
.style-counts{padding:0;gap:10px}.quantity-exact input{padding:7px 9px}
.direction-setting{display:grid;gap:5px;padding:0 12px 12px}.direction-setting select{margin:0;padding:7px;font-size:12px}
.direction-hint{display:flex;align-items:center;gap:7px;font-size:11px;color:var(--muted)}
.direction-hint svg{width:44px;height:25px;flex-shrink:0}
.style-more{flex-wrap:wrap}.style-more .actions{flex-wrap:wrap;gap:9px}.style-more button{line-height:1.8}
.constraint-summary{padding:9px 12px;background:#f0eee6;border-radius:8px;font-size:12px;line-height:1.75;margin-bottom:12px;overflow-wrap:anywhere}
.results-heading{margin:0 0 12px}.plan-tabs{margin-bottom:10px}.paper-top{padding:12px 18px}
.stat-row{padding:14px 18px}.diagram-toolbar{padding:0 18px 10px;flex-wrap:wrap}
.canvas-controls{display:flex;align-items:center;gap:10px}.canvas-controls button{font-size:11px;padding:5px 8px}
.diagram-scroll{max-width:100%;max-height:560px;overscroll-behavior:contain}
.diagram-wrap{padding:0}.diagram-wrap svg{min-height:0;height:auto;max-height:none}
.legend{padding:10px 18px;gap:12px}.animation{padding:14px 18px}
.animation p{min-height:0;margin:8px 0}.animation .heading{margin-bottom:10px}
.piece-detail{display:flex;align-items:center;gap:12px;padding:12px 0;background:transparent;min-height:88px}
.piece-detail img{width:48px;height:48px;flex-shrink:0}.piece-detail strong,.piece-detail span{display:block;overflow-wrap:anywhere}
.piece-description{min-width:0;flex:1}.edge-distances{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;max-width:430px;margin-top:10px}.edge-distance{background:#fffefb;border:1px solid #e3deed;border-radius:8px;padding:7px 10px}.edge-distance strong{font-size:17px;line-height:1.6}.edge-distance small{display:inline;font-size:12px}.edge-distance span{color:#635d72}.piece-detail .position-note{margin-top:8px;font-size:11px}.all-edges{grid-column:1/-1;padding:8px 0}
.piece-detail span{font-size:12px;line-height:1.7}.style-results{padding:5px 18px;grid-template-columns:repeat(auto-fit,minmax(190px,1fr));gap:0 16px}
.style-result{padding:9px 0;gap:8px}.style-result img{width:30px;height:30px}.style-result .count{font-size:17px}
.result-bottom{padding:12px 18px}.result-bottom details{margin-top:8px}
@media(min-width:1700px){.workspace{grid-template-columns:400px minmax(0,1fr);gap:28px}}
@media(max-width:1050px) and (min-width:761px){.workspace{grid-template-columns:320px minmax(0,1fr);gap:16px}.input-section{padding:15px}}
@media(max-width:760px){main{padding:0 14px}.topbar{height:64px;padding:0 14px}.intro{padding:15px 0 18px}.intro h1{font-size:23px}.workspace{display:flex;gap:20px}.input-section{padding:16px}.diagram-toolbar,.animation{padding-left:12px;padding-right:12px}.canvas-controls{width:100%;justify-content:space-between}.style-results{grid-template-columns:1fr}.stat-row{padding:12px;gap:6px}.stat-row .number{font-size:22px}.constraint-summary{font-size:12px}.piece-detail{align-items:flex-start}.piece-detail img{width:40px;height:40px}.results-heading{align-items:center}}