:root{font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif;color-scheme:dark;--bg:#08111f;--surface:#101e34;--glass:#13233bbf;--glass2:#172c49;--border:#283b58;--text:#e8f2ff;--muted:#9fb4ce;--cyan:#50e1df;--violet:#a895ff;--mint:#8af6bd;--warm:#fac574;--btn:#19304f;--ring:#73e5ff;--shadow:#050c1b88;--hero:#101e39}
:root[data-theme="light"]{color-scheme:light;--bg:#eef5fb;--surface:#ffffff;--glass:#e9f1fb;--glass2:#e2ebf8;--border:#cad8e8;--text:#162740;--muted:#52667c;--cyan:#006c8e;--violet:#563eb9;--mint:#10755b;--warm:#874e04;--btn:#e2edfb;--ring:#075cab;--shadow:#96b2c955;--hero:#deedff}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--text);line-height:1.55}body::before{content:"";position:fixed;inset:0;pointer-events:none;z-index:-1;background:radial-gradient(ellipse at 12% 8%,#364ca733,transparent 31%),radial-gradient(ellipse at 90% 4%,#128d9533,transparent 38%)}button,input,select{font:inherit}button,a,summary,input,select{touch-action:manipulation}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.45}a{color:var(--cyan)}:focus-visible{outline:3px solid var(--ring);outline-offset:3px}h1,h2,h3,h4{letter-spacing:-.035em;line-height:1.17}p{line-height:1.67}h1{font-size:clamp(2.5rem,6vw,5.7rem)}h2{font-size:clamp(1.45rem,3vw,2.25rem)}h3{font-size:1.2rem}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}.skip{position:absolute;top:-100px;left:1rem;background:var(--cyan);color:var(--bg);padding:8px;z-index:100}.skip:focus{top:8px}[hidden]{display:none!important}
.topbar{position:sticky;top:0;z-index:20;display:flex;align-items:center;gap:22px;justify-content:space-between;background:color-mix(in srgb,var(--bg) 92%,transparent);backdrop-filter:blur(22px);border-bottom:1px solid var(--border);padding:12px clamp(14px,3.2vw,42px)}.brand{display:flex;align-items:center;gap:10px;color:var(--text);text-decoration:none;min-width:max-content}.brandicon{background:linear-gradient(135deg,#58e9da,#8879ed);border-radius:16px;color:#001522;font-size:2rem;display:grid;place-items:center;width:46px;height:46px;box-shadow:0 0 25px #4ae6ed33}.brand strong{font-size:1rem;letter-spacing:.025em}.brand em{color:var(--cyan);font-style:normal}.brand small{display:block;letter-spacing:.2em;font-weight:750;font-size:.57rem;color:var(--muted)}.mainnav{display:flex;gap:3px;align-items:center;flex-wrap:wrap}.navitem,.toptools button{background:none;color:var(--muted);border:0;border-radius:12px;padding:10px 12px;font-weight:700}.navitem.active,.navitem:hover{background:var(--btn);color:var(--text)}.toptools{display:flex;align-items:center;gap:5px;white-space:nowrap}.xpchip{border-radius:30px;background:#1e3651;color:#ffe3a2;font-weight:750;font-size:.8rem;padding:7px 12px}.toptools #theme-toggle{font-size:1.3rem;border:1px solid var(--border)}.toptools #tutor-toggle{background:linear-gradient(110deg,#16c5d1,#8b78f6);color:#051326;border-radius:13px;padding:11px 14px}
#page-container{max-width:1390px;margin:auto;padding:30px clamp(16px,3.7vw,56px) 70px;min-height:70vh}.footer{border-top:1px solid var(--border);padding:28px 20px;text-align:center;color:var(--muted);font-size:.75rem}.footer p{margin:4px 0}.eyebrow,.number{font-size:.7rem;font-weight:800;letter-spacing:.13em;color:var(--cyan)}.hero{position:relative;min-height:410px;padding:clamp(25px,4vw,58px);border:1px solid var(--border);border-radius:28px;overflow:hidden;background:radial-gradient(circle at 73% 50%,#6c37ba55,transparent 20%),radial-gradient(circle at 88% 50%,#0fcbd255,transparent 22%),linear-gradient(125deg,#0d1b38,var(--hero));display:flex;align-items:center;isolation:isolate}.hero::after{content:"";position:absolute;right:7%;top:4%;width:min(37vw,430px);height:min(37vw,430px);border-radius:100%;background:radial-gradient(circle at 28% 28%,#86fcff,#214d9c 30%,#15194d 65%,#070e31 72%);box-shadow:0 0 70px #26cfff55,0 0 0 24px #83d8ff08,0 0 0 65px #b4e5ff07,0 0 0 102px #a8e3f706;opacity:.83;z-index:-1}.hero-orbit{position:absolute;right:8%;width:min(39vw,470px);height:min(23vw,250px);border:1px solid #8ceaffbb;border-radius:50%;transform:rotate(-31deg);z-index:1}.hero-content{max-width:680px;z-index:2}.hero h1{margin:12px 0;font-size:clamp(2.25rem,4.8vw,4.7rem);max-width:780px}.grad{background:linear-gradient(90deg,#58e6e0,#b09dff,#fcaeb1);color:transparent;background-clip:text}.hero p{max-width:580px;color:#b8c9df;font-size:1.06rem}.chip,.tag{display:inline-block;border:1px solid var(--border);background:var(--glass2);padding:6px 12px;border-radius:30px;font-size:.76rem;font-weight:750;color:var(--muted)}.hero .chip{margin-top:18px;font-size:.68rem;letter-spacing:.02em;color:#cde3fb;background:#102741cf}.actions,.pills{display:flex;flex-wrap:wrap;align-items:center;gap:10px;margin:14px 0}.btn,.labbar button,.back{border:1px solid var(--border);color:var(--text);background:var(--btn);border-radius:12px;padding:12px 18px;font-weight:700;min-height:44px}.btn:hover,.labbar button:hover,.back:hover{border-color:var(--cyan);transform:translateY(-1px)}.primary,.labbar [data-act=play]{background:linear-gradient(110deg,#16c0c9,#85eaa4);color:#062235!important;border:none}.tiny{font-size:.82rem;padding:7px 11px;min-height:36px}.picker-strip{display:flex;align-items:end;flex-wrap:wrap;gap:14px;margin:28px 0;padding:16px 18px;border:1px solid var(--border);border-radius:16px;background:var(--surface)}.picker-strip label,.controlrow label{font-weight:750;font-size:.81rem;color:var(--muted)}.picker-strip select,.controlrow select,input:not([type=checkbox],[type=range]),select{display:block;margin-top:5px;padding:11px 13px;border-radius:11px;border:1px solid var(--border);background:var(--surface);color:var(--text);max-width:100%;min-height:43px}.picker-strip .push{margin-left:auto}.sectiontop{display:flex;align-items:end;justify-content:space-between;margin:37px 0 18px;gap:20px}.sectiontop h2{margin:4px 0}.sectiontop p,.pageheading>p:last-child{color:var(--muted)}.world-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px}.world-card{position:relative;border:1px solid var(--border);text-align:left;background:linear-gradient(145deg,var(--surface),var(--glass));min-height:212px;padding:22px;border-radius:19px;color:var(--text);transition:.18s ease;overflow:hidden}.world-card:hover,.world-card:focus-visible{transform:translateY(-4px);border-color:var(--cyan);box-shadow:0 12px 30px var(--shadow)}.worldglyph{display:grid;place-items:center;width:58px;height:58px;background:linear-gradient(130deg,#13577c,#2b3069);border-radius:19px;color:#8ff4ef;font-size:2.35rem;margin:13px 0}.world-card:nth-child(3n) .worldglyph{background:linear-gradient(130deg,#6f345c,#4d398b);color:#ffe2e4}.world-card:nth-child(4n) .worldglyph{background:linear-gradient(130deg,#5d4b26,#345d6d);color:#ffe5ac}.world-card h3{margin:10px 0;font-size:1.13rem}.world-card p{color:var(--muted);font-size:.87rem;margin:0 0 13px}.world-card .arrow{color:var(--cyan);font-size:.82rem;font-weight:750}.pageheading{padding:16px 0 19px}.pageheading h1{font-size:clamp(2.3rem,4.5vw,4.1rem);margin:12px 0 6px}.pageheading .back{margin-bottom:16px}.pageheading p{max-width:780px}
.labarea{position:relative;background:#071226;border:1px solid #2b4968;border-radius:22px;overflow:hidden;box-shadow:0 22px 60px #03142844}.labcanvas{display:block;touch-action:none;width:100%;height:clamp(310px,48vw,570px);background:radial-gradient(circle at center,#244270,#06101e 68%)}.scenehud{position:absolute;left:12px;right:12px;top:14px;z-index:2;pointer-events:none;display:flex;justify-content:space-between;gap:5px}.scenehud span{border-radius:40px;padding:5px 10px;background:#071a30bb;color:#d3faff;font-weight:700;letter-spacing:.02em;font-size:.7rem}.labbar{display:flex;flex-wrap:wrap;justify-content:center;gap:8px;padding:13px;background:#0b1d35}.labbar button{font-size:.85rem;padding:9px 13px;min-height:42px;background:#173250;color:#f0f6ff}.metrics{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));gap:12px;margin:17px 0}.metric{border-radius:15px;padding:14px 16px;background:var(--surface);border:1px solid var(--border);min-height:91px}.metric b{display:block;font-size:clamp(.88rem,1.5vw,1.25rem);color:var(--text);overflow-wrap:anywhere}.metric small{color:var(--muted)}.model-note,.notice,.formula{padding:15px 18px;border:1px solid var(--border);border-radius:12px;background:var(--glass);color:var(--muted);margin:16px 0}.formula{font-size:1.1rem;font-weight:700;color:var(--cyan)}.question-box{border:1px solid var(--border);border-radius:17px;padding:clamp(14px,3vw,24px);margin:16px 0;background:var(--surface)}.question-box h3,.question-box h4{margin:8px 0 12px}.question-box form{display:flex;flex-wrap:wrap;align-items:end;gap:12px;margin:10px 0}.question-box input{min-width:min(100%,250px);flex:1}.question-box details{border-top:1px solid var(--border);padding-top:12px;margin-top:14px}.question-box .feedback{font-size:.9rem;color:var(--muted)}.feedback.error{color:#f9ac98}.feedback.ok{color:var(--mint)}.panel{border:1px solid var(--border);background:var(--surface);border-radius:15px;margin:13px 0;overflow:hidden}.panel>summary{cursor:pointer;list-style:none;padding:18px 20px;font-weight:800;font-size:1rem;display:flex;align-items:center;justify-content:space-between;min-height:58px}.panel>summary::after{content:'＋';color:var(--cyan);padding-left:8px}.panel[open]>summary::after{content:'－'}.panel>summary::-webkit-details-marker{display:none}.panelbody{padding:0 20px 20px}.panelbody>p{color:var(--muted)}.controls-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:15px}.controlrow{border:1px solid var(--border);background:var(--glass);border-radius:12px;padding:12px}.controlrow output{display:block;color:var(--cyan);font-weight:800;font-size:1.12rem;margin:4px 0 10px}.controlrow input[type=range]{width:100%;accent-color:var(--cyan)}.toggle{display:inline-flex;align-items:center;gap:7px;background:var(--glass);padding:11px 13px;border-radius:10px;color:var(--text);font-weight:650}.toggle input{accent-color:#18bfc1;width:19px;height:19px}.plot-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.plotbox{background:var(--surface);border:1px solid var(--border);border-radius:14px;padding:12px}.plotbox b{font-size:.8rem}.plotbox svg{display:block;width:100%;height:auto;max-height:185px}.axis{stroke:var(--muted);stroke-width:1;fill:none}.graph-line{stroke:var(--cyan);stroke-width:2.4;fill:none;stroke-linecap:round;stroke-linejoin:round}.muted{color:var(--muted);font-size:.88rem}.lessonstep,.mini-step{border-bottom:1px solid var(--border);padding:12px 4px;display:flex;gap:16px}.lessonstep p{margin:0;color:var(--muted)}.time{color:var(--cyan);white-space:nowrap;font-weight:800;min-width:40px}.room-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:15px}.room-card{padding:22px;border:1px solid var(--border);border-radius:16px;background:var(--surface)}.room-card p{color:var(--muted)}.progress-track{height:9px;border-radius:12px;overflow:hidden;background:var(--glass2)}.progress-fill{background:linear-gradient(90deg,#26b6d4,#8af5bb);height:100%;border-radius:12px}.doors{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:10px;margin:18px 0}.door{min-height:94px;border-radius:13px;border:1px solid var(--border);background:var(--glass);color:var(--text);font-size:1.35rem}.door small{display:block;font-size:.61rem;letter-spacing:.06em;font-weight:750}.door.current{border-color:#62e6df;background:#16667955}.door.done{background:#10523c55;border-color:#4cca9f}.glossgrid{display:grid;grid-template-columns:1fr;gap:1px}.glossitem{margin:4px 0}.glossitem .tag{float:right}.teacher-hide .question-box details{display:none}.tag.good{color:var(--mint)}
.tutor-panel{position:fixed;right:20px;bottom:18px;width:min(395px,calc(100vw - 26px));height:min(570px,calc(100dvh - 120px));z-index:40;display:flex;flex-direction:column;border:1px solid var(--border);border-radius:21px;background:var(--surface);box-shadow:0 12px 65px #0008;overflow:hidden}.tutorhead{display:flex;gap:10px;align-items:center;background:var(--glass2);padding:15px}.tutorhead .avatar{font-size:1.9rem;background:#6a79cd;border-radius:13px;color:white;width:47px;text-align:center}.tutorhead strong{display:block}.tutorhead small{display:block;color:var(--muted)}.tutorhead button{margin-left:auto;background:transparent;border:0;color:var(--text);font-size:1.4rem}.tutormessages{flex:1;padding:14px;overflow:auto}.tutormessages p{max-width:95%;border-radius:16px;padding:11px 14px;margin:10px 0;white-space:pre-wrap;font-size:.88rem}.tutormessages .bot{background:var(--glass2);margin-right:auto}.tutormessages .me{background:#156b87;color:white;margin-left:auto}.tutorform{display:flex;align-items:center;padding:12px;gap:7px;border-top:1px solid var(--border)}.tutorform input{flex:1;min-width:0}.tutorform button{border:0;border-radius:11px;min-width:45px;min-height:45px;background:var(--cyan);color:var(--bg);font-weight:800}
@media(max-width:1100px){.topbar{flex-wrap:wrap}.mainnav{order:3;width:100%;overflow-x:auto;flex-wrap:nowrap}.world-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.metrics{grid-template-columns:repeat(3,minmax(0,1fr))}}
@media(max-width:700px){#page-container{padding:16px 12px 65px}.topbar{padding:9px 12px;gap:10px}.brand strong{font-size:.77rem}.brand small{font-size:.48rem}.brandicon{height:37px;width:37px;font-size:1.5rem}.toptools{margin-left:auto}.xpchip{display:none}.mainnav .navitem{padding:10px}.hero{min-height:360px;padding:24px;border-radius:19px}.hero::after{right:-26%;top:9%;width:65vw;height:65vw;opacity:.48}.hero-orbit{right:-27%;width:77vw;height:44vw}.hero p{font-size:.93rem}.hero h1{font-size:2.5rem}.world-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.world-card{min-height:190px;padding:13px;border-radius:13px}.world-card h3{font-size:.96rem}.world-card p{font-size:.77rem}.worldglyph{width:43px;height:43px;font-size:1.65rem;margin:10px 0}.metrics{grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.room-grid{grid-template-columns:1fr}.plot-grid{grid-template-columns:1fr}.doors{grid-template-columns:repeat(3,minmax(0,1fr))}.scenehud span:last-child{display:none}.labbar{justify-content:flex-start}.labbar button{font-size:.75rem;padding:8px}.picker-strip .push{margin:0}.tutor-panel{right:8px;bottom:8px}.sectiontop{align-items:start}}
@media(prefers-reduced-motion:reduce){*,*::after,*::before{scroll-behavior:auto!important;animation:none!important;transition:none!important}}@media print{.topbar,.tutor-panel,.labbar,.world-grid,.actions{display:none!important}body{background:white;color:black}#page-container{padding:0}.panel{break-inside:avoid}}
.term-modal{width:min(560px,94vw);max-height:80dvh;overflow:auto;padding:24px;border-radius:19px;border:1px solid var(--border);background:var(--surface);color:var(--text);box-shadow:0 20px 80px #0009}.term-modal::backdrop{background:#051322c9;backdrop-filter:blur(4px)}.termtop{display:flex;justify-content:space-between;gap:15px;align-items:center}.termtop h2{margin:0}.termtop button{border:1px solid var(--border);border-radius:9px;background:var(--glass);color:var(--text);font-size:1.2rem;min-width:44px;height:44px}.term-modal p{margin:12px 0}.tutormessages .lab-link{display:block;background:var(--btn);color:var(--cyan);border-radius:11px;padding:10px 13px;border:1px solid var(--border);font-weight:750;margin:10px 0}