:root,:root[data-theme=dark]{--bg:#0c0d12;--ink:#eef0f8;--muted:#a0a5b8;--gold:#baa5f4;--line:#282b39;--panel:#151820;--soft:#191c27;--surface:#13151d;--accent-soft:#28213b;--glass:rgba(17,19,27,.88);--shadow:0 24px 70px #0005;color-scheme:dark}
:root[data-theme=light]{--bg:#f4f4f8;--ink:#20212d;--muted:#636579;--gold:#674bb2;--line:#dedee8;--panel:#151820;--soft:#ededf5;--surface:#fff;--accent-soft:#eae4f8;--glass:rgba(249,249,253,.9);--shadow:0 20px 65px #2020300a;color-scheme:light}
*{box-sizing:border-box}html{scroll-padding-top:calc(var(--navigation-height,86px) + 16px)}body{font-family:"Segoe UI",Arial,"Nirmala UI",sans-serif;font-size:16px;line-height:1.65;background:radial-gradient(ellipse at 85% 9%,#8871c211,transparent 32%),var(--bg);color:var(--ink)}button,input,select{font:inherit}button,a,input,select{touch-action:manipulation}button{min-height:42px;font-weight:600}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid var(--gold);outline-offset:5px}a{color:inherit}button{cursor:pointer}button:disabled{cursor:default;opacity:.55}main{max-width:1440px;padding:0 48px;margin:auto}
header{position:sticky;top:0;z-index:40;max-width:none;margin:auto;padding:18px max(30px,calc((100vw - 1380px)/2));min-height:86px;background:var(--glass);backdrop-filter:blur(18px);border-bottom:1px solid var(--line);gap:30px}.brand{font-size:13px;letter-spacing:1.7px;flex-shrink:0}.brand small{font-size:7px;font-weight:500;letter-spacing:1.15px;margin-top:4px;color:var(--muted)}.mark{background:linear-gradient(145deg,#e9e6f4,#9891ac);border:1px solid #ffffff35;color:#171620;box-shadow:inset 0 1px 2px #fff7;width:39px;height:39px;font-size:29px}nav{margin-left:auto;gap:28px;font-size:12px}nav a{white-space:nowrap}nav a:hover{color:var(--gold)}.header-actions{display:flex;align-items:center;gap:8px}.header-actions .quiet{font-size:11px;min-height:38px;padding:8px 12px}.quiet{color:var(--ink);border:1px solid var(--line);background:var(--surface);border-radius:9px;padding:9px 14px;font-size:12px;box-shadow:inset 0 1px 0 #ffffff06}.quiet:hover{border-color:var(--gold);background:var(--soft)}.install-button{background:var(--ink);color:var(--bg);border:1px solid transparent;min-height:38px;border-radius:9px;padding:9px 15px;font-size:11px}.button,a.button{border:1px solid #ffffff30;background:var(--ink);color:var(--bg);border-radius:11px;font-size:13px;font-weight:650;padding:15px 22px;min-height:52px;box-shadow:0 5px 20px #0002;gap:35px;margin:0}.button:hover{transform:translateY(-1px)}
.hero{display:grid;grid-template-columns:1.04fr 1fr;gap:7%;padding:78px 0 62px;align-items:center;max-width:none}.hero h1{font-family:inherit;font-weight:600;font-size:clamp(52px,5.8vw,82px);letter-spacing:-4px;line-height:1.05;margin:26px 0}.hero h1 em{font-style:normal;font-weight:500;background:linear-gradient(105deg,#d5d0eb,#a293c9 60%,#787083);background-clip:text;-webkit-background-clip:text;color:transparent}.hero .intro{color:var(--muted);font-size:16px;max-width:455px;line-height:1.8;margin-bottom:30px}.eyebrow{font-size:9px;letter-spacing:1.8px;line-height:1.7;color:var(--gold);font-weight:600;margin-bottom:10px}.status-dot{display:inline-block;width:6px;height:6px;border-radius:50%;background:var(--gold);box-shadow:0 0 12px #bda9f680;margin-right:9px;vertical-align:middle}.hero-actions{display:flex;align-items:center;gap:24px;flex-wrap:wrap}.hero-secondary{font-size:12px;color:var(--muted);padding:10px 0;white-space:nowrap}.hero-secondary span{margin-left:10px;color:var(--ink)}.hero-metrics{display:flex;gap:0;margin-top:38px;max-width:440px}.hero-metrics>span{font-size:10px;color:var(--muted);padding:0 28px;border-left:1px solid var(--line)}.hero-metrics>span:first-child{padding-left:0;border:0}.hero-metrics strong{display:block;font-family:inherit;font-size:28px;font-weight:500;line-height:1.3;color:var(--ink);font-variant-numeric:tabular-nums;margin-bottom:3px}.hero-note{font-size:8px;letter-spacing:1.2px;margin-top:24px;color:var(--muted)}.hero-art{position:relative;background:radial-gradient(ellipse at 50% 46%,#34304777,transparent 62%),linear-gradient(160deg,#1e202b,#101117);border:1px solid #323443;border-radius:28px;box-shadow:var(--shadow),inset 0 1px 0 #ffffff09;min-width:0;padding:22px;max-width:520px;width:100%;justify-self:end;color:#d8d8e4;overflow:hidden;transform:none}.hero-art:before{content:'';position:absolute;left:0;right:0;top:0;height:1px;background:linear-gradient(90deg,transparent,#aa9dcd70,transparent)}.art-label,.art-bottom{display:flex;align-items:center;justify-content:space-between;font-size:8px;letter-spacing:1.1px;gap:12px;position:relative;z-index:1}.art-label i{display:inline-block;width:5px;height:5px;margin-right:7px;background:#c9bee2;border-radius:50%}.threeui-scene{position:relative;width:100%;height:355px;isolation:isolate;overflow:hidden;border-radius:14px}.scene-fallback{width:100%;height:100%;display:block}.art-bottom{border-top:1px solid #ffffff10;padding-top:15px}.art-bottom .quiet{font-size:9px;min-height:30px;background:transparent;border-color:#ffffff20;color:#d3cde7;padding:5px 9px}.scene-caption{font-size:9px;margin:12px 0 0;color:#9692a9;position:relative;z-index:1}.path{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;padding:24px 0;max-width:none;margin:0;border-color:var(--line);font-size:11px;color:var(--muted)}.path b{color:var(--gold);font-weight:500;padding-right:13px}
.section{padding:56px 0}.section-heading{display:flex;justify-content:space-between;align-items:center;gap:24px;margin-bottom:26px}.section-heading h2,h2{font-family:inherit;font-weight:550;font-size:31px;line-height:1.25;letter-spacing:-1px;margin-bottom:8px}.section-heading>div>p:not(.eyebrow){max-width:700px;color:var(--muted);font-size:13px}.section-link{font-size:11px;color:var(--muted);white-space:nowrap;padding:10px 0}.section-link:hover{color:var(--gold)}.featured{padding:44px 0 54px;border-bottom:1px solid var(--line)}.featured-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.feature-card{display:flex;flex-direction:column;position:relative;padding:22px;background:linear-gradient(140deg,#ffffff04,transparent),var(--surface);border:1px solid var(--line);border-radius:20px;box-shadow:inset 0 1px 0 #ffffff08;overflow:hidden;isolation:isolate;transition:transform .22s,border-color .22s,box-shadow .22s;transform-style:preserve-3d}.feature-heading{display:flex;align-items:center;justify-content:space-between}.card-arrow{font-size:18px;color:var(--muted);line-height:1}.feature-card h3{font-size:20px;line-height:1.35;letter-spacing:-.45px;font-weight:550;margin:12px 0}.feature-card>p{font-size:12px;color:var(--muted);line-height:1.7;max-width:300px;margin-bottom:20px}.feature-footer{font-size:9px;display:flex;justify-content:space-between;gap:10px;margin-top:auto;padding-top:17px;border-top:1px solid var(--line);color:var(--muted)}.feature-footer>span{color:var(--gold)}.course-index{font-size:9px;letter-spacing:1.2px;color:var(--gold);font-weight:500}.feature-card:hover,.course-card:hover{border-color:#87799f;box-shadow:0 12px 35px #0002,inset 0 1px 0 #ffffff10;transform:perspective(850px) rotateX(var(--tilt-x,0deg)) rotateY(var(--tilt-y,0deg)) translateY(-4px)}
.course-discover{border-bottom:1px solid var(--line)}.connection-status{font-size:10px;display:inline-flex;align-items:center;gap:8px;background:var(--soft);border:1px solid var(--line);color:var(--muted);padding:7px 12px;border-radius:24px;white-space:nowrap}.connection-status:before{content:'';height:5px;width:5px;background:#bcc9b8;border-radius:50%}.connection-status.is-offline:before{background:#d5b884}.course-tools{display:flex;justify-content:space-between;align-items:flex-end;gap:22px}.course-grades{display:flex;gap:5px;padding:5px;border:1px solid var(--line);border-radius:12px;background:var(--surface)}.course-grades button{font-size:12px;min-height:38px;border:0;color:var(--muted);background:transparent;border-radius:8px;padding:8px 22px;font-weight:500}.course-grades button.active{background:var(--soft);color:var(--ink);box-shadow:inset 0 1px 0 #ffffff0a}.discovery-search{font-size:10px;color:var(--muted)}input[type=search],.library-picker input{background:var(--surface);border:1px solid var(--line);border-radius:10px;color:var(--ink);padding:12px 14px;font-size:12px;min-height:44px}.discovery-search input{width:310px}.course-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;margin-top:23px}.course-card{display:flex;flex-direction:column;align-items:stretch;position:relative;text-align:left;padding:18px;min-height:270px;border:1px solid var(--line);border-radius:17px;background:linear-gradient(155deg,#ffffff04,transparent),var(--surface);color:var(--ink);gap:8px;box-shadow:inset 0 1px 0 #ffffff07;overflow:hidden;transition:transform .22s,border-color .22s,box-shadow .22s;transform-style:preserve-3d;isolation:isolate}.course-card h3{font-family:inherit;font-size:15px;line-height:1.45;font-weight:550;letter-spacing:-.15px;margin:5px 0 10px;min-height:42px}.course-card .course-count{font-size:10px;color:var(--muted);font-weight:400;padding-top:14px;border-top:1px solid var(--line);margin-top:auto;line-height:1.4}.course-card:disabled{transform:none}.course-description{font-size:11px!important;line-height:1.6;color:var(--muted);font-weight:400;margin:0 0 12px}.session-note{display:flex;justify-content:space-between;gap:25px;color:var(--muted);font-size:10px;margin:25px 0 0}#session-score{color:var(--gold)}kbd{font-family:inherit;background:var(--surface);border:1px solid var(--line);border-radius:4px;padding:1px 5px}.saved-list{display:flex;gap:8px;flex-wrap:wrap}#saved-labs{margin-top:26px}#saved-labs h3{font-size:15px;font-weight:500}
#lab{scroll-margin-top:0}.pill{border:1px solid var(--line);background:var(--soft);color:var(--muted);font-size:10px;border-radius:30px;padding:7px 13px}.library-picker{display:grid;grid-template-columns:1.05fr 1fr;gap:18px;padding:18px 20px;border:1px solid var(--line);border-radius:15px;background:var(--surface);margin-bottom:16px}.library-picker label{font-size:10px;color:var(--muted)}.library-picker select,.library-picker input{width:100%;min-height:43px;font-size:12px;margin-top:6px;background:var(--bg)}.library-shortcuts,.practical-filters{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:20px}.library-shortcuts button,.practical-filters button{font-size:10px;min-height:35px;padding:6px 12px;color:var(--muted)}.practical-filters button[aria-pressed=true]{color:var(--gold);border-color:var(--gold);background:var(--accent-soft)}.workspace{display:grid;grid-template-columns:218px minmax(0,1fr)!important;background:var(--surface);border:1px solid var(--line);border-radius:20px;overflow:visible;align-items:start;box-shadow:0 20px 60px #0001}.lesson-list{position:sticky;top:calc(var(--navigation-height,86px) + 16px);max-height:calc(100dvh - var(--navigation-height,86px) - 32px);overflow:auto;padding:24px 14px;background:var(--bg);border-right:1px solid var(--line);border-radius:20px 0 0 20px;align-self:start;width:100%}.lesson-list h3{font-family:inherit;font-size:14px;font-weight:550;line-height:1.5;margin-bottom:18px}.lesson-list .lesson{width:100%;border:1px solid transparent;border-radius:10px;background:transparent;color:var(--muted);text-align:left;font-size:11px;padding:12px 10px;margin-bottom:5px;min-height:58px}.lesson.active{background:var(--soft);border-color:var(--line);color:var(--ink)}.lesson-list .lesson.active{border-color:#74668d;background:var(--soft);color:var(--ink)}.lesson span{color:var(--gold);font-size:10px}.lesson small{display:block;padding-left:24px;font-size:9px!important;margin-top:4px;line-height:1.45;font-weight:400;color:var(--muted)}.lesson.is-checked small{color:var(--gold)}.aside-note{font-size:10px;color:var(--muted);border-top:1px solid var(--line);padding-top:20px;margin-top:22px}.lesson-list>a{font-size:10px;color:var(--gold)}.lesson-main{padding:24px;min-width:0;min-height:620px}.at-glance{display:none!important}.lesson-topbar{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;border-bottom:1px solid var(--line);padding-bottom:14px;margin-bottom:22px}.tabs{display:flex;border:0;padding:4px;background:var(--bg);border-radius:10px;gap:3px;margin:0}.tabs button{font-size:12px;background:transparent;border:0;color:var(--muted);padding:9px 16px;min-height:38px;border-radius:7px;font-weight:500}.tabs button.active{background:var(--soft);color:var(--ink);box-shadow:inset 0 1px 0 #ffffff10}.lesson-actions{display:flex;gap:6px}.lesson-actions button{font-size:10px;min-height:34px;padding:6px 10px}.lesson-actions button[aria-pressed=true]{background:var(--accent-soft);border-color:var(--gold);color:var(--gold)}#action-status:empty{display:none}#action-status{font-size:11px!important;color:var(--gold)}.lesson-main h3{font-family:inherit;font-size:25px;font-weight:550;letter-spacing:-.45px;line-height:1.35}.lesson-main p{font-size:14px;line-height:1.8}.lab-guide{margin:22px 0 20px}.lab-guide b{font-size:18px;font-weight:550}.lab-guide p{font-size:12px;color:var(--muted);line-height:1.7;margin-top:6px}.analogy,.learning-caution{background:var(--soft);border:1px solid var(--line);border-left:2px solid var(--gold);border-radius:0 12px 12px 0;padding:18px 22px;margin:24px 0}.analogy b,.learning-caution b{font-size:11px;color:var(--gold);font-weight:500}.analogy p,.learning-caution p{margin:7px 0 0}.lesson-support details,.learning-context{border-top:1px solid var(--line);padding:15px 0}.lesson-support summary,.learning-context summary{font-size:12px;color:var(--muted);cursor:pointer;min-height:28px}.learning-context p{font-size:12px;color:var(--muted)}
.experiment-toolbar{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:12px}.experiment-toolbar>span{font-size:8px;letter-spacing:1.5px;color:var(--muted)}.experiment-toolbar button{font-size:9px;min-height:31px;padding:5px 10px}.sim-workbench{display:grid;grid-template-columns:minmax(0,1fr) 236px;gap:18px;align-items:start}.sim-visual{min-width:0}.stage,.sim-stage{background:#14171e;border:1px solid #2f3341;border-radius:15px;padding:16px 10px 8px;overflow-x:auto;min-width:0;box-shadow:inset 0 1px 0 #ffffff08}.sim-stage svg{display:block;width:100%;min-width:0;min-height:0}.stage-top,.sim-stage .stage-top{font-size:7px;letter-spacing:1.1px;color:#969bac;gap:10px}.diagram-enlarged .sim-stage svg{min-width:720px}.sim-control-panel{padding:18px;border:1px solid var(--line);border-radius:14px;background:var(--bg);min-width:0;box-shadow:inset 0 1px 0 #ffffff04}.sim-control-panel h4{font-size:13px;font-weight:550;margin:0 0 6px}.control-hint{font-size:10px!important;color:var(--muted);margin-bottom:14px;line-height:1.65!important}.sim-presets{display:flex;gap:7px;flex-wrap:wrap;margin:10px 0 18px}.sim-presets button{font-size:9px;min-height:32px;padding:7px 9px;line-height:1.4;background:var(--surface)}.sim-controls{display:grid;grid-template-columns:1fr;gap:19px;margin:0}.sim-controls label,.controls label{font-size:11px;color:var(--muted);line-height:1.6}.sim-controls output{font-size:12px;display:block;float:none;color:var(--ink);font-variant-numeric:tabular-nums;margin:4px 0 0}.sim-controls input[type=range],input[type=range]{accent-color:var(--gold);min-height:28px;margin-top:7px}.sim-controls select,select{background:var(--surface);color:var(--ink);border:1px solid var(--line);font-size:12px;min-height:40px;border-radius:8px}.sim-controls select{margin-top:6px}.sim-defaults{width:100%;margin-top:22px;font-size:9px;min-height:36px}.sim-transport{display:flex;align-items:center;gap:9px;flex-wrap:wrap;margin:15px 0;padding:12px;background:var(--bg);border:1px solid var(--line);border-radius:13px}.sim-play{background:var(--ink);color:var(--bg);border:0;border-radius:8px;font-size:11px;padding:9px 18px;min-height:39px}.sim-reset{font-size:10px}.sim-transport .time-control{order:3;flex-basis:100%;min-width:0;font-size:11px;color:var(--muted)}.sim-transport .rate-control{margin-left:auto;font-size:9px;min-width:67px;flex:0}.sim-rate{font-size:10px;min-height:31px;margin:0;padding:4px;background:var(--surface)}.sim-readouts,.readouts{gap:16px;border-color:var(--line);padding:17px 0;margin-bottom:0}.sim-readouts>div{min-width:0}.readouts strong,.sim-readouts strong{font-family:inherit;font-size:18px;font-weight:500;color:var(--ink);font-variant-numeric:tabular-nums}.readouts small,.sim-readouts small{font-size:8px;letter-spacing:.5px;line-height:1.7;color:var(--muted);margin-bottom:6px}.model-details{margin-top:20px;border-top:1px solid var(--line);padding-top:15px}.model-details summary{font-size:11px;color:var(--muted);cursor:pointer;min-height:30px}.sim-formula{font-size:12px!important;color:var(--ink);margin-top:16px}.sim-assumptions{font-size:11px!important;color:var(--muted)}.subtle{font-size:11px!important;color:var(--muted)}.sound-controls{display:flex;align-items:center;flex-wrap:wrap;gap:12px;margin:16px 0}.sound-controls span{font-size:10px;color:var(--muted)}.sound-controls button[aria-pressed=true]{border-color:var(--gold);color:var(--gold);background:var(--accent-soft)}.sim-mobile-hint{display:none}.new-lab .controls input[type=text],.new-lab .controls input[type=number]{background:var(--bg);color:var(--ink);border-color:var(--line)}.base-grid{grid-template-columns:repeat(4,minmax(0,1fr))}.base-grid label{font-size:11px}.base-grid small{font-size:10px}
#practice{padding:10px 0;border:0;margin:0;max-width:750px}.answers{display:grid;grid-template-columns:1fr;gap:12px;margin:26px 0}.answers button{min-height:58px;padding:17px;text-align:left;font-size:14px;border:1px solid var(--line);border-radius:12px;background:var(--bg);color:var(--ink);font-weight:400}.answers button:before{content:attr(data-choice);display:inline-grid;place-items:center;width:26px;height:26px;margin-right:14px;border:1px solid var(--line);border-radius:7px;color:var(--muted);font-size:11px}.answers button.is-correct{border-color:var(--gold);background:var(--accent-soft)}.answers button.is-wrong{border-color:#d48888}#feedback{font-size:12px;color:var(--gold)}#solution{font-size:13px;background:var(--soft);border:1px solid var(--line);border-radius:12px;padding:20px}.lab-navigation{display:flex;justify-content:space-between;gap:14px;margin-top:26px;padding-top:22px;border-top:1px solid var(--line)}.lab-navigation button{font-size:11px}
.chapter-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px}.chapter{padding:20px;border:1px solid var(--line);background:var(--surface);border-radius:15px;box-shadow:inset 0 1px 0 #ffffff04}.chapter h3{font-family:inherit;font-size:16px;line-height:1.5;font-weight:550}.chapter .status{font-size:9px;background:var(--soft);color:var(--muted);border-color:var(--line)}.concept{font-size:12px;border-color:var(--line)}.concept small{font-size:9px;line-height:1.8;color:var(--muted)}.concept a{font-size:11px;display:inline-block;padding:8px 0;color:var(--gold)}.filters{gap:10px}.filters .grade{font-size:11px;min-height:42px;border:1px solid var(--line);background:var(--surface);color:var(--muted);border-radius:9px}.filters .grade.active{background:var(--soft);color:var(--ink);border-color:var(--gold)}.search-label{font-size:10px;color:var(--muted)}.practicals{background:var(--surface);border:1px solid var(--line);border-radius:15px}.practicals summary{font-size:14px}.practicals>p{font-size:11px!important}#practical-list{columns:3;font-size:12px}#practical-list p{break-inside:avoid;margin-bottom:14px}.sources h2{font-size:26px}.sources p,#source-links a{font-size:12px;color:var(--muted)}.sources{gap:7%;border-top:1px solid var(--line)}footer{border-top:1px solid var(--line);font-size:9px;letter-spacing:1px;color:var(--muted);padding:28px max(30px,calc((100vw - 1380px)/2))}.skip-link{position:fixed;left:20px;top:-80px;z-index:100;padding:12px 18px;background:var(--ink);color:var(--bg);border-radius:10px}.skip-link:focus{top:12px}.update-banner{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);z-index:70;max-width:90vw;border:1px solid var(--line);border-radius:12px;padding:15px 24px;background:var(--ink);color:var(--bg);font-size:12px;box-shadow:var(--shadow)}dialog{background:var(--surface);color:var(--ink);border:1px solid var(--line);border-radius:20px;padding:30px;max-width:480px;width:calc(100% - 40px);box-shadow:var(--shadow)}dialog::backdrop{background:#0009;backdrop-filter:blur(4px)}dialog h2{font-size:25px}dialog p{font-size:13px}.focus-mode .hero,.focus-mode .path,.focus-mode .featured,.focus-mode #discover,.focus-mode #roadmap,.focus-mode #sources,.focus-mode footer{display:none}.focus-mode #lab{padding-top:25px}.focus-mode .workspace{grid-template-columns:minmax(0,1fr)!important}.focus-mode .lesson-list{display:none}.focus-mode .sim-workbench{grid-template-columns:minmax(0,1fr) 290px}.focus-mode .lesson-main{min-height:calc(100dvh - 170px)}
@media(min-width:1600px){.sim-workbench{grid-template-columns:minmax(0,1fr) 270px}}
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:root{--card-topic-color:var(--muted)}:root[data-theme=light] .hero h1 em{background-image:linear-gradient(110deg,#51466d,#796394 70%,#4d475b)}.threeui-scene:focus-visible{outline:2px solid #b8a6dd;outline-offset:2px}.threeui-scene-options button{font-size:12px;min-height:40px}.art-bottom .quiet{font-size:11px;min-height:36px}.course-art-topic{font-size:11px}.course-card .course-count{font-size:12px}.sim-controls label,.controls label{font-size:13px}.sim-controls output{font-size:14px}.sim-controls select{font-size:14px}.sim-readouts small,.readouts small{font-size:10px}.experiment-toolbar button{font-size:12px;min-height:38px}.control-hint{font-size:12px!important}.sim-presets button{font-size:11px;min-height:38px}.sim-play,.sim-reset{font-size:12px}.sim-transport .time-control{font-size:12px}.sim-transport .rate-control,.sim-rate{font-size:11px}.sim-assumptions,.sim-formula{font-size:12px!important}
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.scene-caption{font-size:11px}.scene-fallback[hidden]{display:none!important}
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