/* The shared SuDu mark, colour field and footer frame the instrument. */
:root{--paper:#f3f1ea;--ink:#171613;--ground:var(--paper);--muted:var(--ink);--line:color-mix(in srgb,var(--ink) 24%,var(--paper));--faint:color-mix(in srgb,var(--ink) 6%,var(--paper));--rail:max(clamp(20px,4.5vw,64px),calc((100% - 1760px)/2));--header:102px;--tools:64px;font-family:'Urbanist',Arial,sans-serif;color-scheme:light;color:var(--ink);background:var(--paper)}
:root.dm{--paper:var(--dm-bg,#121110);--ink:#f5f3ec;color-scheme:dark}
*{box-sizing:border-box}html,body{margin:0;width:100%;height:100%;overflow:hidden;background:var(--paper);color:var(--ink)}body{-webkit-font-smoothing:antialiased}button,input,select{font:inherit;color:inherit}button,a,input,select,summary{-webkit-tap-highlight-color:transparent}button,a,summary{touch-action:manipulation}button{border:0;background:transparent;cursor:pointer;padding:0}a{color:inherit;text-decoration:none}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible,canvas:focus-visible{outline:2px solid var(--ink);outline-offset:3px}button:disabled{opacity:.45;cursor:default}[hidden]{display:none!important}svg{fill:none;stroke:currentColor;stroke-width:1.3;stroke-linecap:round;stroke-linejoin:round}
.masthead{position:fixed;inset:0 0 auto;height:var(--header);z-index:20;display:flex;align-items:flex-end;justify-content:space-between;gap:16px;padding:34px var(--rail) 30px;background:var(--paper)}.brand{display:block;flex:none}.brand img{display:block;width:auto;height:38px}.dm .brand img{filter:brightness(0) invert(1)}.app-title{margin:0;padding-bottom:2px;line-height:1.4;font-size:13px;font-weight:500;letter-spacing:.02em}
.workspace{position:fixed;inset:var(--header) 0 calc(var(--sudu-tool-footer,48px) + var(--tools));display:grid;grid-template-columns:minmax(0,1fr) 310px;gap:28px;padding:0 var(--rail);min-height:0}.workspace.reading-expanded{grid-template-columns:minmax(0,1fr) min(420px,42vw)}.workspace.focus-mode{grid-template-columns:1fr}.focus-mode .structures{display:none}.stage{position:relative;min-width:0;min-height:0;overflow:hidden}.stage-top{position:absolute;inset:14px 0 auto;display:flex;justify-content:space-between;gap:16px;pointer-events:none;z-index:1;font-size:12px;line-height:1.5;letter-spacing:.03em}.stage-top span:last-child{letter-spacing:0;text-align:right}canvas{display:block;width:100%;height:100%;touch-action:none;cursor:grab}canvas:active{cursor:grabbing}.stage-coordinate,.model-hint{display:none}
.structures{min-width:0;overflow:auto;overscroll-behavior:contain;padding:0 0 24px 24px;border-left:.5px solid var(--line);scrollbar-width:thin;scrollbar-color:var(--line) transparent}.mode-tabs,.reading-tabs,.segmented{display:flex;align-items:center;gap:24px;border-bottom:.5px solid var(--line)}.mode-tabs{position:sticky;top:0;z-index:2;background:var(--paper);margin-bottom:24px}.mode-tabs button,.reading-tabs button,.segmented button{min-height:44px;font-size:14px;position:relative;white-space:nowrap}.mode-tabs button[aria-pressed=true],.reading-tabs button[aria-pressed=true],.segmented button[aria-pressed=true]{font-weight:600}.mode-tabs button[aria-pressed=true]:after,.reading-tabs button[aria-pressed=true]:after,.segmented button[aria-pressed=true]:after{content:'';position:absolute;bottom:-1px;left:0;right:0;height:2px;background:var(--ink)}
.subject-heading{display:flex;align-items:baseline;justify-content:space-between;gap:12px}.subject-heading h2{margin:0;font-size:24px;font-weight:500;line-height:1.2;letter-spacing:-.5px}#form-position{font-size:12px;white-space:nowrap;font-variant-numeric:tabular-nums}.subject-basis{margin:16px 0 8px;font-size:12px;line-height:1.6}.subject-copy{margin:0;font-size:15px;line-height:1.6}.form-step{display:flex;justify-content:space-between}.form-step button{min-height:44px;font-size:13px}select{max-width:100%;width:100%;background:var(--paper);border:0;border-bottom:.5px solid var(--line);border-radius:0;min-height:44px;font-size:15px;padding:0 20px 0 0}#form-select{font-size:17px;margin-top:12px}#form-instance-control{display:flex;align-items:center;gap:16px}#form-instance-control label{margin:0;flex:none}#form-instance{margin-left:auto;width:auto;max-width:75%;flex:1}
.adjustments{margin-top:22px}.adjustments label:not(.check-label){display:flex;justify-content:space-between;gap:16px;align-items:center;font-size:13px;line-height:1.5;margin-top:14px}.adjustments output{font-size:12px;font-variant-numeric:tabular-nums}.segmented{gap:24px}.segmented button{font-size:13px}.check-label{display:flex;align-items:center;gap:10px;font-size:13px;min-height:44px;cursor:pointer}input[type=checkbox]{accent-color:var(--ink);width:16px;height:16px;margin:0}input[type=range]{display:block;appearance:none;-webkit-appearance:none;width:100%;height:36px;background:transparent;margin:0;cursor:pointer}input[type=range]::-webkit-slider-runnable-track{height:1px;background:var(--ink)}input[type=range]::-moz-range-track{height:1px;background:var(--ink)}input[type=range]::-webkit-slider-thumb{appearance:none;-webkit-appearance:none;background:var(--ink);border:3px solid var(--paper);outline:1px solid var(--ink);width:13px;height:13px;border-radius:50%;margin-top:-6px}input[type=range]::-moz-range-thumb{background:var(--ink);border:3px solid var(--paper);outline:1px solid var(--ink);width:7px;height:7px;border-radius:50%}.control-note{font-size:13px;line-height:1.6;margin:4px 0 0}.selection-note{border-top:.5px solid var(--line);padding-top:18px;margin-top:18px}.selection-note p{font-size:14px;line-height:1.6}.selection-note .text-link{display:block}.eyebrow{font-size:11px;line-height:1.5;font-weight:500;letter-spacing:.08em;margin:0 0 10px}.text-link{font-size:13px;min-height:44px;display:inline-flex;align-items:center;text-decoration:underline;text-underline-offset:5px;text-decoration-thickness:.5px}.reading{margin-top:24px;border-top:.5px solid var(--line)}.reading>summary{display:none;cursor:pointer;min-height:44px;align-items:center;justify-content:space-between;font-size:14px}.reading-tabs{gap:22px}.reading-tabs button{font-size:13px}.article{padding-top:20px;font-size:15px;line-height:1.65;overflow-wrap:anywhere}.article-kicker{font-size:11px;line-height:1.6;letter-spacing:.03em;margin-bottom:10px}.article h2{font-size:21px;line-height:1.3;font-weight:500;letter-spacing:-.4px;margin:0 0 12px}.article h3{font-size:16px;font-weight:600;margin:24px 0 8px}.article p{margin:0 0 16px}.article .lede{font-size:16px;line-height:1.55}.article a,.sources a{text-decoration:underline;text-underline-offset:3px}.article ul,.article ol{padding-left:20px}.article li{margin-bottom:8px}.article .reading-note{border-left:1px solid var(--ink);padding-left:14px;font-size:14px}.reading-actions{display:flex;align-items:center;justify-content:space-between;gap:16px}.sources{border-top:.5px solid var(--line);padding-top:4px;margin-top:20px}.sources a,.sources button{display:block;font-size:14px;line-height:1.5;text-align:left;padding:10px 0;text-decoration:underline;text-underline-offset:3px;min-height:44px}.related{border-top:.5px solid var(--line);padding-top:16px;margin-top:24px}.related button{display:block;text-align:left;min-height:44px;font-size:14px;text-decoration:underline;text-underline-offset:3px}.index-link{margin-top:20px}.construction-steps{padding:0;list-style:none}.construction-steps li{border-top:.5px solid var(--line);padding:16px 0}.construction-steps strong{display:block;margin-bottom:6px}.math-line{font-size:14px;padding:16px 0;border-block:.5px solid var(--line)}
.footer{position:fixed;inset:auto 0 var(--sudu-tool-footer,48px);height:var(--tools);padding:0 var(--rail);display:flex;align-items:center;gap:24px;background:var(--paper)}.footer>span{font-size:12px;letter-spacing:.025em}.footer-actions{display:flex;align-items:center;gap:18px;order:3}.footer-actions button{min-height:44px;font-size:13px;text-decoration:underline;text-underline-offset:5px;text-decoration-thickness:.5px}.view-toolbar{display:flex;align-items:center;gap:3px;white-space:nowrap;margin-left:auto;order:2}.view-toolbar button{width:36px;height:44px;display:grid;place-items:center}.view-toolbar button svg{width:18px;height:18px}.toolbar-line{width:.5px;height:14px;margin:0 4px;background:var(--line)}#zoom-value{font-size:12px;width:38px;text-align:center;font-variant-numeric:tabular-nums}
dialog{color:var(--ink);background:var(--paper);border:.5px solid var(--line);box-shadow:none;padding:0}dialog::backdrop{background:rgb(0 0 0 / .28)}.library-dialog{position:fixed;inset:28px var(--rail) calc(var(--sudu-tool-footer,48px) + 20px);margin:0 0 0 auto;width:min(760px,calc(100% - 2 * var(--rail)));height:auto;max-width:none;max-height:none}.library-shell{display:flex;flex-direction:column;height:100%;min-height:0}.library-header{display:flex;align-items:center;gap:24px;padding:24px 28px;border-bottom:.5px solid var(--line);flex:none}.library-header>div{margin-right:auto}.library-header h2{font-size:30px;font-weight:400;margin:0}.library-header .eyebrow{margin-bottom:6px}.close-button{width:44px;height:44px;font-size:28px;flex:none}.library-index{overflow:auto;overscroll-behavior:contain;padding:20px 28px 32px;scrollbar-width:thin}.search-box{display:block;border-bottom:1px solid var(--ink)}.search-box input{width:100%;min-height:48px;background:transparent;border:0;font-size:16px;border-radius:0;padding:0}.search-box input::placeholder{color:var(--ink);opacity:1}.category-tabs{display:flex;flex-wrap:wrap;gap:0 22px;margin:12px 0 20px}.category-tabs button{min-height:44px;font-size:13px}.category-tabs .active{text-decoration:underline;text-underline-offset:6px;font-weight:600}.article-item{display:grid;grid-template-columns:30px minmax(0,1fr) auto;align-items:baseline;gap:12px;text-align:left;width:100%;min-height:58px;padding:16px 0;border-top:.5px solid var(--line);font-size:16px;line-height:1.5}.article-number,.article-category{font-size:11px}.article-item.active .article-name{text-decoration:underline;text-underline-offset:4px}.small-dialog{width:min(570px,calc(100% - 32px));max-height:calc(100% - 80px);padding:32px;overflow:auto}.small-dialog>.close-button{float:right;margin:-16px -16px 0 12px}.small-dialog h2{font-size:30px;font-weight:400;line-height:1.2;margin:20px 0}.small-dialog p{font-size:16px;line-height:1.7}.primary-button{border-bottom:1px solid var(--ink);min-height:44px;font-size:14px}.help-list{margin:20px 0 0}.help-list div{padding:14px 0;border-top:.5px solid var(--line)}.help-list dt{font-size:14px;font-weight:600;margin-bottom:5px}.help-list dd{margin:0;font-size:14px;line-height:1.6}.sr-only,.skip{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.skip:focus{position:fixed;top:8px;left:16px;width:auto;height:auto;clip:auto;margin:0;padding:12px;background:var(--paper);z-index:100}.noscript{position:fixed;inset:35% 20%;padding:30px;background:var(--paper);border:1px solid var(--ink)}
@media(max-width:1000px){.workspace{grid-template-columns:minmax(0,1fr) 290px;gap:20px}.structures{padding-left:20px}.stage-top{flex-direction:column;gap:4px}.stage-top span:last-child{text-align:left}.footer{gap:16px}}
@media(max-width:760px){:root{--header:70px;--tools:86px;--rail:20px}.masthead{align-items:center;padding:20px var(--rail) 14px}.brand img{height:32px}.app-title{padding:0}.workspace,.workspace.reading-expanded{grid-template-columns:minmax(0,1fr);grid-template-rows:minmax(120px,1fr) auto;gap:0;padding:0 var(--rail)}.stage{grid-row:1}.stage-top{inset:5px 0 auto;flex-direction:row;font-size:10px}.stage-top span:last-child{text-align:right}.structures{grid-row:2;max-height:38svh;border-left:0;border-top:.5px solid var(--line);padding:0 0 14px;overflow:auto}.reading-expanded .structures{max-height:48svh}.mode-tabs{gap:30px;margin-bottom:16px}.subject-heading h2{font-size:21px}.subject-basis{margin:10px 0 6px}.subject-copy{font-size:14px;line-height:1.55}.form-step button{min-height:40px}.adjustments{margin-top:14px}#object-controls{display:grid;grid-template-columns:1fr 1fr;gap:0 24px}#object-controls .segmented,#object-controls .check-label{grid-column:1/-1}.reading{margin-top:16px}.reading>summary{display:flex}.reading[open]>summary span{transform:rotate(45deg)}.reading-tabs{gap:28px}.article{font-size:15px;padding-top:16px}.article h2{font-size:21px}.footer{display:grid;grid-template-columns:minmax(0,1fr) auto;grid-template-rows:38px 44px;gap:0 8px;padding:0 var(--rail) 4px}.footer>span{font-size:11px}.footer-actions{grid-column:2;grid-row:1}.footer-actions button{min-height:38px;font-size:12px}.footer .view-toolbar{grid-column:1/-1;grid-row:2;justify-content:center;margin:0}.view-toolbar button{width:42px}.workspace.focus-mode{grid-template-rows:1fr}.library-dialog{inset:12px 12px calc(var(--sudu-tool-footer,48px) + 12px);width:auto}.library-header{padding:18px 20px;gap:12px}.library-index{padding:16px 20px 28px}.article-item{grid-template-columns:24px minmax(0,1fr);gap:8px;font-size:15px}.article-category{display:none}.small-dialog{padding:24px}}
@media(max-height:540px) and (orientation:landscape){:root{--header:62px;--tools:48px}.masthead{padding:14px var(--rail)}.brand img{height:30px}.workspace,.workspace.reading-expanded{grid-template-columns:minmax(0,1fr) 280px;grid-template-rows:minmax(0,1fr);gap:20px}.stage{grid-row:1;grid-column:1}.structures{grid-row:1;grid-column:2;max-height:none!important;border-left:.5px solid var(--line);border-top:0;padding-left:16px}.workspace.focus-mode{grid-template-columns:1fr}.footer{display:flex}.footer .view-toolbar{margin-left:auto}.footer>span{display:none}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;transition:none!important}}

/* Keep context and the return control available throughout a long reading. */
.reading{scroll-margin-top:52px}.reading-tabs{position:sticky;top:44px;z-index:1;background:var(--paper)}#reading-overview{margin-left:auto;font-size:12px;text-decoration:underline;text-underline-offset:4px}
@media(max-width:760px){.reading-tabs{gap:20px}}
/* Discovery: visible families and geometry controls around the object. */
.mode-tabs{margin-bottom:12px}.shape-browser{margin-bottom:22px}.family-tabs{display:flex;gap:24px;border-bottom:.5px solid var(--line)}.family-tabs button{position:relative;min-height:44px;font-size:14px}.family-tabs button[aria-pressed=true]{font-weight:600}.family-tabs button[aria-pressed=true]:after{content:'';position:absolute;inset:auto 0 -1px;height:2px;background:var(--ink)}.shape-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:2px 8px;margin-top:10px}.shape-grid button{min-height:86px;min-width:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:4px;padding:5px 3px;font-size:12px;line-height:1.3;border-bottom:1px solid transparent}.shape-grid button svg{display:block;width:56px;height:48px;stroke-width:.9;transition:transform .18s ease}.shape-grid button span{min-height:30px;display:flex;align-items:center;text-align:center}.shape-grid button[aria-pressed=true]{background:var(--faint);border-bottom-color:var(--ink);font-weight:600}.shape-grid button:hover svg{transform:scale(1.08)}.shape-grid button:hover{background:var(--faint)}.family-copy{font-size:12px;line-height:1.5;margin:12px 0 0}.subject-heading h2{font-size:23px}.subject-basis{margin:10px 0 7px}.subject-copy{font-size:14px;line-height:1.6}.adjustments{margin-top:12px}.instance-picker{display:flex;align-items:center;gap:4px;border-bottom:.5px solid var(--line);margin-top:12px;font-size:13px}.instance-picker>button{min-width:40px;min-height:44px}.instance-picker>span{font-variant-numeric:tabular-nums;min-width:52px;text-align:center}.instance-picker #instance-all{margin-left:auto;min-width:90px}.instance-picker #instance-all[aria-pressed=true]{text-decoration:underline;text-underline-offset:5px}#object-controls>summary{min-height:44px;font-size:13px;cursor:pointer;align-content:center}#object-controls{display:block}.reading>summary{display:flex}.reading{margin-top:16px}.reading[open]>summary span{transform:rotate(45deg)}.index-link{margin-top:8px}.discovery-dock{position:absolute;inset:auto 0 0;display:flex;flex-direction:column;align-items:center;gap:2px;padding:8px 0 10px;background:var(--paper)}.shape-stepper{display:flex;align-items:center;justify-content:center;gap:20px}.shape-stepper button{width:48px;height:44px;font-size:22px}.shape-stepper span{font-size:22px;line-height:1.25;letter-spacing:-.3px;min-width:140px;text-align:center}.model-actions{display:flex;align-items:center;gap:20px}.model-actions button{min-height:44px;font-size:13px;text-decoration:underline;text-decoration-thickness:.5px;text-underline-offset:5px}.model-actions button[aria-pressed=true]{font-weight:600}.discovery-next{font-size:15px;font-weight:500;min-height:44px;border-bottom:1px solid var(--ink);padding:0 4px}.discovery-next:hover{background:var(--faint)}#touch-hint{font-size:11px;line-height:1.5;margin:8px 0 0}.focus-mode .discovery-dock{background:transparent}.focus-mode .discovery-next,.focus-mode .model-actions{display:none}
@media(max-width:760px){.structures{max-height:29svh}.shape-browser{margin-bottom:16px}.mode-tabs{margin-bottom:0}.family-tabs{gap:30px}.family-tabs button{min-height:40px;font-size:14px}.shape-grid{display:flex;gap:10px;overflow-x:auto;overscroll-behavior-x:contain;scroll-snap-type:x mandatory;scrollbar-width:thin;margin:6px 0 0;padding-bottom:4px}.shape-grid button{flex:0 0 84px;min-height:82px;scroll-snap-align:start}.shape-grid button svg{width:48px;height:42px}.shape-grid button span{min-height:28px}.family-copy{display:none}.discovery-dock{gap:0;padding:4px 0 6px}.shape-stepper{gap:12px}.shape-stepper span{font-size:18px;min-width:130px}.shape-stepper button{height:36px;font-size:20px}.model-actions{gap:18px}.model-actions button{min-height:36px;font-size:12px}.discovery-next{min-height:40px;font-size:13px}#touch-hint{display:none}.reading-expanded .structures{max-height:48svh}#object-controls{display:block}}
@media(hover:none){.shape-grid button:hover svg{transform:none}}
/* Translated labels retain their reading size and wrap within the SuDu rail. */
.shape-grid button span,.subject-heading h2,.article h2,.article-name{overflow-wrap:anywhere;hyphens:auto}
.reading-tabs{gap:12px}.reading-tabs button{min-width:0;white-space:normal}
.shape-stepper{max-width:100%}.shape-stepper span{min-width:0;overflow-wrap:anywhere;hyphens:auto}.shape-stepper button{flex:none}
.model-actions{max-width:100%;flex-wrap:wrap;justify-content:center;column-gap:18px;row-gap:0}
.discovery-next{max-width:100%;line-height:1.4;padding:8px 4px;text-align:center}
.stage-top>span{min-width:0;overflow-wrap:anywhere}.stage-top>span:last-child{max-width:45%}
html[lang=ja] .article{line-height:1.85}html[lang=ja] .shape-grid button span{word-break:normal;overflow-wrap:normal}
.reading>summary>span{flex:none;margin-inline:6px}