@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700&family=Manrope:wght@400;500;600;700;800&display=swap');
:root{--blue:#255cf4;--navy:#132550;--muted:#69758d;--line:#e2e8f3;--ink:#132550;--paper:#f6f8fd;font-family:'DM Sans','Segoe UI',sans-serif;background:var(--paper);color:var(--ink)}
body{margin:0}button,a,input,select{-webkit-tap-highlight-color:transparent}button,a{touch-action:manipulation}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #6087ff;outline-offset:4px}h1,h2,h3,.wordmark{font-family:Manrope,'Segoe UI',sans-serif}a{text-decoration:none}button{font:inherit}.n-icon{width:21px;height:21px;fill:none;stroke:currentColor;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round;flex:none}.wordmark{display:flex;align-items:center;gap:10px;font-size:24px;letter-spacing:-1px;font-weight:800;color:var(--ink)}.wordmark img{width:38px;height:38px}.eyebrow,.n-kicker{font-size:12px;letter-spacing:.15em;font-weight:700;text-transform:uppercase}.n-kicker{color:#7d8da9}.n-button{display:inline-flex;align-items:center;justify-content:center;gap:20px;min-height:48px;padding:12px 21px;border-radius:12px;font-weight:600;font-size:14px;cursor:pointer;border:1px solid var(--line);background:white;color:var(--ink);transition:transform .2s,background .2s,box-shadow .2s}.n-button:hover{transform:translateY(-2px);box-shadow:0 6px 20px #13255012}.n-button.blue{background:var(--blue);border-color:var(--blue);color:white}.n-button.white{background:#fff;color:#1641b1;border-color:white}.n-button.ghost{background:#ffffff0d;color:#cbd9ff;border-color:#ffffff2e}.n-tag{display:inline-flex;align-items:center;gap:7px;font-size:12px;line-height:1.3;padding:6px 10px;border:1px solid var(--line);border-radius:6px;color:var(--muted);font-weight:500}.n-tag.light{border-color:#ffffff2e;background:#ffffff0b;color:#d2e1ff}.n-link{display:inline-flex;align-items:center;gap:10px;color:var(--blue);font-size:14px;font-weight:600}.n-link:hover{text-decoration:underline;text-underline-offset:5px}
/* The entrance is an animated, mathematical night sky. */
.portal{position:fixed;inset:0;z-index:100;background:#06132f;color:white;overflow:auto;isolation:isolate;display:flex;flex-direction:column;min-height:100dvh}.portal:before{content:'';position:absolute;inset:0;z-index:-2;background:radial-gradient(ellipse at 51% 53%,#1643a873,transparent 55%),radial-gradient(ellipse at 80% 0,#2445c540,transparent 50%)}.portal canvas{position:absolute;inset:0;width:100%;height:100%;z-index:-1}.portal-header{display:flex;justify-content:space-between;align-items:center;padding:30px 5vw;gap:20px}.portal .wordmark{color:white;font-size:27px}.portal .wordmark img{width:42px;height:42px}.portal-header .n-tag{color:#b5c8e9;border-color:#ffffff25}.portal-center{flex:1;display:flex;flex-direction:column;justify-content:center;align-items:center;text-align:center;padding:60px 24px 85px;position:relative}.portal-orbit{position:absolute;width:min(67vw,760px);aspect-ratio:1;border:1px solid #87a9ff16;border-radius:50%;pointer-events:none;z-index:-1;transform:rotate(-25deg) scaleY(.6)}.portal-orbit:after,.portal-orbit:before{content:'';position:absolute;inset:12%;border:1px solid #87a9ff16;border-radius:50%}.portal-orbit:after{inset:-16%}.portal-center .n-kicker{color:#96baff;margin-bottom:25px;letter-spacing:.23em}.portal h1{font-size:clamp(46px,6.8vw,94px);font-weight:500;line-height:1.1;letter-spacing:-.065em;max-width:920px}.portal h1 em{font-family:Georgia,serif;font-weight:400;letter-spacing:-.06em;background:linear-gradient(110deg,#8ec5ff,#c4d8ff 65%,#7babfa);color:transparent;background-clip:text}.portal-center>p{max-width:440px;font-size:17px;line-height:1.75;color:#a9bbd8;margin:25px 0 30px}.enter-button{padding:17px 27px;min-width:200px;border-radius:50px;box-shadow:0 0 45px #5c94ff26;font-size:16px}.portal-caption{margin-top:22px;color:#8399bd;font-size:12px;letter-spacing:.08em}.portal-footer{padding:22px 5vw 30px;display:flex;justify-content:space-between;align-items:center;gap:15px;font-size:12px;color:#7189b0}.portal-footer button{background:transparent;border:0;color:#9fb5da;cursor:pointer;font-size:12px;padding:10px}.portal.launching{animation:portal-out .85s .2s both}.portal.launching .portal-center{animation:portal-zoom .85s both}@keyframes portal-out{to{opacity:0;visibility:hidden}}@keyframes portal-zoom{to{transform:scale(1.2);filter:blur(12px);opacity:0}}
/* Observatory shell */
.n-sidebar{position:fixed;inset:0 auto 0 0;width:218px;z-index:20;background:#fff;border-right:1px solid var(--line);padding:30px 22px;display:flex;flex-direction:column}.n-sidebar .wordmark{margin-bottom:40px}.subject-pill{padding:13px 12px;background:#f4f7fd;border:1px solid var(--line);border-radius:10px;display:flex;align-items:center;gap:10px;font-size:14px;font-weight:600}.subject-pill .n-icon{color:var(--blue)}.subject-pill span:last-child{margin-left:auto;font-size:12px;background:white;padding:2px 6px;border-radius:4px;color:var(--muted)}.nav-label{margin:29px 12px 12px;color:#95a0b3;font-size:12px;letter-spacing:.12em;font-weight:600}.n-nav{display:grid;gap:6px}.n-nav a{display:flex;align-items:center;gap:12px;color:#6a768b;padding:12px;border-radius:9px;font-size:14px;font-weight:500}.n-nav a:hover{background:#f5f7fc;color:var(--blue)}.n-nav a[aria-current=page]{color:var(--blue);background:#edf2ff;font-weight:700}.n-sidebar-bottom{margin-top:auto;padding-top:40px}.orbit-mini{height:65px;position:relative;display:grid;place-items:center;color:#5079e5;font-family:Georgia,serif;font-size:30px}.orbit-mini:before{content:'';position:absolute;width:88px;height:33px;border:1px solid #c6d6ff;border-radius:50%;transform:rotate(-25deg)}.sidebar-note{text-align:center;color:#8c97ab;font-size:12px;line-height:1.7}.n-replay{display:flex;align-items:center;justify-content:center;gap:8px;width:100%;padding:13px 0;margin-top:25px;border:0;border-top:1px solid var(--line);background:white;color:#74809a;font-size:12px;cursor:pointer}.n-app{margin-left:218px;min-height:100vh}.n-topbar{display:flex;align-items:center;justify-content:space-between;padding:21px 40px;border-bottom:1px solid var(--line);background:#ffffffb8;gap:18px;min-height:79px}.n-breadcrumb{font-size:13px;color:#8b97ae;display:flex;align-items:center;gap:12px}.n-breadcrumb strong{color:#465571;font-weight:500}.topbar-right{display:flex;gap:12px;align-items:center;color:#687690;font-size:12px}.avatar{width:32px;height:32px;border-radius:50%;background:#e8efff;color:#255cf4;display:grid;place-items:center}.n-page{max-width:1380px;margin:0 auto;padding:38px 40px 46px}.n-page-heading{display:flex;align-items:flex-end;justify-content:space-between;gap:20px;margin-bottom:27px}.n-page-heading h1{font-weight:700;font-size:clamp(29px,3.1vw,42px);letter-spacing:-.055em;line-height:1.22;margin-top:7px}.n-page-heading p:not(.n-kicker){font-size:15px;color:var(--muted);margin-top:9px}.n-heading-note{font-size:12px;color:#8995a9;white-space:nowrap}.journey-grid{display:grid;grid-template-columns:1.15fr 1fr 1fr;gap:18px}.journey-card{border:1px solid var(--line);border-radius:18px;background:white;padding:25px;min-height:308px;display:flex;flex-direction:column;position:relative;overflow:hidden;isolation:isolate;transition:transform .25s,box-shadow .25s}.journey-card:hover{transform:translateY(-4px);box-shadow:0 14px 30px #163a7010}.journey-card .step{font-size:12px;color:#8e99af;letter-spacing:.12em}.journey-card h2{font-size:25px;font-weight:700;letter-spacing:-.045em;line-height:1.25;margin-top:15px}.journey-card p{font-size:14px;line-height:1.65;color:var(--muted);margin-top:10px;max-width:225px}.journey-card .n-link{margin-top:auto;padding-top:25px}.journey-card .card-icon{width:48px;height:48px;border-radius:13px;display:grid;place-items:center;background:#edf3ff;color:var(--blue);margin:22px 0 0}.journey-card .card-icon .n-icon{width:26px;height:26px}.journey-card.learn{background:linear-gradient(135deg,#1644cd,#2c64f2);border-color:#285bea;color:white}.journey-card.learn .step{color:#b2caff}.journey-card.learn p{color:#cbdaff;max-width:190px}.journey-card.learn .n-link{color:white}.journey-card.learn h2{position:relative;z-index:1;font-size:29px;margin-top:26px;max-width:160px}.planet-art{position:absolute;width:170px;height:170px;right:-48px;top:36px;border-radius:50%;background:radial-gradient(circle at 27% 28%,#b1e2ff,#60a5ff 15%,#397ae8 35%,#1b49b4 58%,#132856 83%);box-shadow:-8px -4px 35px #a7d5ff3c,inset -22px -18px 30px #071b625c;z-index:-1}.planet-art:before{content:'';position:absolute;inset:-27px;border:1px solid #a8ccff55;border-radius:50%;transform:rotate(-27deg) scaleY(.48)}.planet-art:after{content:'';position:absolute;inset:11px;border:1px dashed #b8dcff50;border-radius:50%;transform:rotate(28deg) scaleX(.48)}.card-art{position:absolute;right:-22px;top:42px;width:155px;height:130px;color:#d4e0fe;z-index:-1;transform:rotate(-12deg);opacity:.9}.card-art .n-icon{width:130px;height:130px;stroke-width:.5}.journey-card .card-foot{border-top:1px solid #ffffff25;margin-top:auto;padding-top:18px;display:flex;justify-content:space-between;align-items:center}.journey-card .card-foot .n-link{padding:0}.journey-card .card-foot>span{font-size:12px;color:#b7cdff}.n-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;padding:21px 0;border-bottom:1px solid var(--line);margin-bottom:30px}.n-stat{display:flex;align-items:center;justify-content:center;gap:12px;border-right:1px solid var(--line)}.n-stat:last-child{border:0}.n-stat strong{font-size:22px;font-weight:600;letter-spacing:-.04em}.n-stat span{font-size:12px;color:var(--muted)}.section-heading{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:18px}.section-heading h2{font-size:20px;letter-spacing:-.035em}.section-heading p{color:var(--muted);font-size:13px;margin-top:3px}.topic-universe{display:grid;grid-template-columns:repeat(5,1fr);gap:12px}.topic-tile{display:flex;flex-direction:column;min-height:165px;padding:19px 17px;background:white;border:1px solid var(--line);border-radius:13px;color:var(--ink);position:relative;overflow:hidden;transition:background .2s,border-color .2s}.topic-tile:hover{background:#edf3ff;border-color:#9db8ff}.topic-symbol{font-family:Georgia,serif;font-size:32px;font-style:italic;color:#527de6;line-height:1.2;margin-bottom:14px}.topic-tile h3{font-size:14px;letter-spacing:-.025em;font-weight:600;line-height:1.4;max-width:125px}.topic-tile small{font-size:12px;color:#8491a7;margin-top:auto;padding-top:10px}.topic-tile .tile-arrow{position:absolute;right:14px;top:14px;color:#a5b7d9;font-size:16px}.featured-strip{margin-top:26px;padding:19px 23px;display:flex;align-items:center;gap:20px;border-radius:12px;background:#eaf0ff;border:1px solid #dce6ff}.feature-symbol{width:46px;height:46px;display:grid;place-items:center;background:#fff;border:1px solid #d5e3ff;border-radius:50%;font-size:23px;font-family:Georgia,serif;color:var(--blue);flex:none}.featured-strip h3{font-size:14px;font-weight:600}.featured-strip p{font-size:13px;color:#6d7f9f;margin-top:2px}.featured-strip .n-link{margin-left:auto;white-space:nowrap}.n-footer{margin-top:35px;display:flex;align-items:center;justify-content:space-between;font-size:12px;color:#94a0b5;gap:20px}.n-footer span:last-child{font-family:Georgia,serif;letter-spacing:.18em}
/* Shared study and practice treatment. */
.selection-view{padding:38px 40px;max-width:1280px}.page-heading .eyebrow{font-size:12px;letter-spacing:.15em}.page-heading h1{font-family:Manrope,'Segoe UI',sans-serif;font-size:36px}.page-heading>p:last-child{font-size:15px}.topic-panel,.options-panel{border-radius:16px;box-shadow:0 3px 14px #13255003}.options-panel{border-top:3px solid #5680ff}.topic-group summary{font-size:16px}.topic-group[open]>summary{color:var(--blue)}.primary-button{background:var(--blue);border-color:var(--blue);border-radius:10px}.start-bar{background:#10275b;color:white;border-color:#10275b;box-shadow:0 10px 35px #10275b24}.start-bar p{color:#b2c6e8}.start-bar .primary-button{background:#fff;color:#1943a5;border-color:white}.practice-toolbar{background:#ffffffef;backdrop-filter:blur(12px)}.question-card{box-shadow:0 4px 20px #15346a05;border-radius:18px;padding:30px}.question-head h2{font-size:17px}.question-head{border-bottom:1px solid var(--line);padding-bottom:17px}.help-toggle{border-radius:9px}.practice-heading h1{font-size:32px}.practice-content{max-width:990px}.n-error{padding:24px;border:1px solid #dfe6f4;border-radius:12px;background:white;color:var(--muted)}
@media(min-width:1600px){.n-page{padding-top:50px}.journey-card{min-height:335px}.topic-tile{min-height:185px}}
@media(max-width:1150px){.n-sidebar{width:190px;padding:26px 16px}.n-app{margin-left:190px}.n-page,.selection-view{padding:30px 26px}.n-topbar{padding:21px 26px}.journey-card{padding:22px;min-height:310px}.journey-card h2{font-size:23px}.journey-card.learn h2{font-size:26px}.planet-art{right:-77px}.topic-universe{gap:9px}.topic-tile{padding:16px 13px}}
@media(max-width:900px){.n-sidebar{width:80px;padding:24px 13px}.n-sidebar .wordmark span,.subject-pill,.nav-label,.n-nav a span,.n-sidebar-bottom{display:none}.n-sidebar .wordmark{justify-content:center;margin-bottom:30px}.n-nav a{justify-content:center;padding:15px 10px}.n-app{margin-left:80px}.journey-grid{gap:12px}.journey-card{padding:20px;min-height:320px}.journey-card h2{font-size:22px}.journey-card p{font-size:13px}.journey-card .card-foot>span{display:none}.topic-universe{grid-template-columns:repeat(3,1fr)}.topic-tile{min-height:160px}.n-heading-note{display:none}}
@media(max-width:650px){.portal-header{padding:24px}.portal-header .n-tag{font-size:12px}.portal h1{font-size:clamp(42px,10vw,62px)}.portal-center{padding-top:38px;padding-bottom:45px}.portal-center>p{font-size:16px;max-width:300px}.portal-footer{padding:18px 24px}.portal-footer>span{max-width:180px}.portal-caption{font-size:12px}.n-sidebar{inset:auto 0 0;width:100%;height:70px;border-right:0;border-top:1px solid var(--line);padding:7px 10px;background:#fffffff5;backdrop-filter:blur(16px)}.n-sidebar>.wordmark{display:none}.n-nav{grid-template-columns:repeat(4,1fr);gap:3px}.n-nav a{padding:6px 0;flex-direction:column;gap:4px;font-size:12px;border-radius:8px}.n-nav a span{display:block}.n-nav a .n-icon{width:20px;height:20px}.n-app{margin-left:0;padding-bottom:70px}.n-topbar{min-height:66px;padding:17px 20px}.n-page,.selection-view{padding:25px 20px}.n-breadcrumb{font-size:12px}.topbar-right>span:first-child{display:none}.n-page-heading{margin-bottom:22px}.n-page-heading h1{font-size:30px}.n-page-heading p:not(.n-kicker){font-size:14px}.journey-grid{grid-template-columns:1fr 1fr}.journey-card.learn{grid-column:1/-1;min-height:242px;padding:24px}.journey-card.learn h2{max-width:210px;margin-top:15px;font-size:30px}.journey-card.learn p{max-width:230px;margin-bottom:20px}.journey-card.learn .planet-art{width:195px;height:195px;right:-25px;top:0}.journey-card{min-height:260px;padding:18px}.journey-card h2{font-size:22px}.journey-card p{font-size:13px}.journey-card .card-icon{width:36px;height:36px;margin-top:15px}.journey-card .card-icon .n-icon{width:21px}.journey-card .n-link{font-size:13px;padding-top:20px;gap:8px}.card-art{right:-60px}.n-stats{gap:8px;padding:20px 0;margin-bottom:24px}.n-stat{flex-direction:column;gap:0}.n-stat strong{font-size:20px}.n-stat span{font-size:12px}.topic-universe{grid-template-columns:repeat(2,1fr);gap:10px}.topic-tile{min-height:150px;padding:17px}.topic-tile:last-child{grid-column:1/-1;min-height:95px;display:grid;grid-template-columns:45px 1fr;align-items:center;gap:5px 10px}.topic-tile:last-child h3{max-width:none}.topic-tile:last-child .topic-symbol{grid-row:1/3;margin:0}.topic-tile:last-child small{grid-column:2;padding:0;margin:0}.featured-strip{padding:17px;gap:13px;flex-wrap:wrap}.featured-strip>div{flex:1}.featured-strip .n-link{margin-left:59px}.section-heading .n-link{font-size:12px}.n-footer{align-items:flex-start;font-size:12px}.n-footer span:last-child{display:none}.selection-layout{grid-template-columns:1fr}.page-heading h1{font-size:30px}.start-bar{bottom:80px}.question-card{padding:21px 16px}.n-page-heading .n-tag{display:none}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}
body[data-motion=off] *,body[data-motion=off] *:before,body[data-motion=off] *:after{animation:none!important;transition:none!important}
/* The Discovery Lab */
/* The three entry points share the Discovery Lab's blue treatment. */
.journey-card{background:linear-gradient(135deg,#1644cd,#2c64f2);border-color:#285bea;color:white}
.journey-card .step{color:#b2caff}.journey-card p{color:#cbdaff}.journey-card .n-link{color:white}
.journey-card .card-icon{background:#ffffff1a;border:1px solid #ffffff24;color:#e0ecff}
.journey-card .card-art{color:#aacaff;opacity:.3}
/* Sculpted versions of the existing UI motifs, lit from the upper left like the planet. */
.dimensional-art{position:absolute;right:-44px;top:37px;width:162px;height:162px;display:grid;place-items:center;z-index:-1;pointer-events:none;color:#c7e5ff}
.dimensional-art .n-icon{width:78%;height:78%;stroke-width:1.35;filter:drop-shadow(1px 2px 0 #123b92) drop-shadow(-1px -1px 0 #ddf2ff70)}
.target-art{border-radius:50%;border:1px solid #b2dcff80;background:radial-gradient(circle at 27% 24%,#b1e2ff,#60a5ff 20%,#397ae8 44%,#1b49b4 72%,#132856);transform:perspective(450px) rotateY(-24deg) rotateX(13deg) rotate(-12deg);box-shadow:2px 3px 0 #3065bd,4px 6px 0 #2453aa,7px 10px 0 #183c85,14px 20px 28px #0a23683d,inset 2px 2px 4px #d2ecff80,inset -14px -12px 20px #112c6b55}
.target-art .n-icon{stroke:#c5e5ff;fill:#76afff16}
.paper-art{right:-23px;top:40px;width:126px;height:160px;border-radius:13px;border:1px solid #b1d8ffb3;background:radial-gradient(ellipse at 22% 18%,#b1e2ff,#70b0ff 30%,#3e7edf 58%,#2050a5 90%);transform:perspective(450px) rotateY(-25deg) rotateX(12deg) rotate(-14deg);box-shadow:3px 4px 0 #82b4f4,5px 6px 0 #2e63b5,8px 10px 0 #a0c9fb,10px 12px 0 #285396,13px 16px 0 #173c80,19px 25px 30px #0a23683d,inset 2px 2px 5px #e2f3ff99,inset -9px -9px 18px #12367655}
.paper-art .n-icon{width:83%;height:83%;stroke:#d9ecff;fill:#9ac7ff20}
@media(max-width:1150px){.target-art{right:-72px}.paper-art{right:-47px}}
@media(max-width:650px){.target-art{right:-68px;top:33px;width:150px;height:150px}.paper-art{right:-43px;top:35px;width:117px;height:149px}}
.start-bar .primary-button:hover:not(:disabled){background:#e9f0ff;color:#173e92}
@media(max-width:650px){.portal-header .n-tag{display:none}}
.lab-hero{min-height:337px;display:grid;grid-template-columns:1.1fr 1fr;position:relative;isolation:isolate;overflow:hidden;border-radius:20px;background:radial-gradient(ellipse at 75% 40%,#264fbc,#102966 60%,#102355);color:white;padding:34px}.lab-hero-text{z-index:1}.lab-hero .n-kicker{color:#8dabed;margin:24px 0 9px;letter-spacing:.14em}.lab-hero h2{font-size:clamp(30px,3.2vw,44px);line-height:1.16;letter-spacing:-.05em;font-weight:500}.lab-hero-text>p:not(.n-kicker){max-width:380px;font-size:15px;color:#bccdec;margin-top:16px;line-height:1.7}.lab-actions{display:flex;align-items:center;flex-wrap:wrap;gap:18px;margin-top:25px}.lab-actions>span{font-size:12px;color:#a4b9df}.lab-orbit{position:relative;min-height:260px;display:grid;place-items:center;z-index:0}.lab-planet{width:180px;height:180px;border-radius:50%;background:radial-gradient(ellipse at 25% 25%,#a7d7ff,#559cff 24%,#2869c8 43%,#163767 68%,#0c1c3d 88%);box-shadow:-6px -5px 35px #8dc9ff40,0 0 100px #518eff30;position:relative}.lab-planet:before{content:'';position:absolute;inset:10px;border-radius:50%;border:1px solid #9bcfff63;transform:rotate(24deg) scaleX(.42)}.lab-planet:after{content:'';position:absolute;inset:26px -42px;border:1px solid #83afff60;border-radius:50%;transform:rotate(-25deg);animation:orbit-breathe 9s ease-in-out infinite}.lab-rays{position:absolute;width:350px;height:160px;border:1px solid #a3c5ff25;border-radius:50%;transform:rotate(-24deg)}.lab-rays:before,.lab-rays:after{content:'';position:absolute;width:6px;height:6px;left:18px;top:23px;background:#a8d3ff;box-shadow:0 0 14px #acd8ff;border-radius:50%}.lab-rays:after{left:auto;top:auto;right:18px;bottom:23px;background:#6d9bff}.orbit-label{position:absolute;font-size:12px;letter-spacing:.12em;color:#a5c8ff}.l1{top:22px;left:10px}.l2{right:-2px;bottom:60px}.orbit-equation{position:absolute;bottom:5px;font-family:Georgia,serif;font-style:italic;letter-spacing:.05em;color:#8ea9d7;font-size:18px}.notes-heading{margin-top:34px}.lesson-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.lesson-tile{background:white;border:1px solid var(--line);border-radius:14px;padding:22px;color:var(--ink);display:flex;flex-direction:column;transition:transform .2s,border .2s,box-shadow .2s}.lesson-tile:hover{transform:translateY(-3px);border-color:#aac1ff;box-shadow:0 8px 20px #153d7810}.lesson-tile-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:20px}.lesson-number{font-size:12px;color:#8794ac;font-variant-numeric:tabular-nums}.lesson-symbol{font-family:Georgia,serif;font-size:27px;font-style:italic;color:#7f9deb;line-height:1}.lesson-tile h3{font-size:17px;line-height:1.35;font-weight:600;letter-spacing:-.03em}.lesson-tile>p{font-size:14px;color:var(--muted);line-height:1.65;margin:10px 0 20px}.lesson-tile-foot{margin-top:auto;border-top:1px solid #ecf0f7;padding-top:14px;display:flex;align-items:center;justify-content:space-between;font-size:12px;color:#8190aa}.lesson-tile-foot span:last-child{color:var(--blue);font-size:17px}.lab-next{display:flex;align-items:center;gap:14px;background:#edf2ff;border:1px solid #e0e8fc;border-radius:13px;margin-top:28px;padding:23px}.lab-next>div{flex:1}.lab-next h3{font-size:18px;margin-top:5px;font-weight:600}.lab-next .n-kicker{font-size:12px}.lab-next .n-button{font-size:13px;padding:11px 16px;gap:12px}
/* The Exam Archive */
.archive-intro{display:flex;align-items:center;gap:20px;background:#eaf0ff;border:1px solid #dce6ff;border-radius:14px;padding:24px 27px;margin-bottom:25px}.archive-emblem{display:grid;place-items:center;flex:none;width:55px;height:55px;background:white;border-radius:14px;color:var(--blue)}.archive-emblem .n-icon{width:28px;height:28px}.archive-intro h2{font-size:18px}.archive-intro p{font-size:14px;margin-top:4px;color:#6b7d9c}.archive-total{margin-left:auto;text-align:right;white-space:nowrap;padding-left:20px}.archive-total strong{font-size:29px;letter-spacing:-.04em;display:block;line-height:1.2}.archive-total span{font-size:12px;color:#7d8ba5}.archive-filters{display:grid;grid-template-columns:1.2fr 1fr 1fr 1fr auto;gap:18px;align-items:end;padding:21px 24px;background:white;border:1px solid var(--line);border-radius:13px}.archive-filters label{font-size:12px;font-weight:600;color:#697a96}.archive-filters select{margin-top:7px;font-size:14px;border-color:#dfe6f2;border-radius:8px;min-height:43px}.archive-reset{min-height:43px;padding:7px 6px;border:0;background:transparent;color:#7a8ca9;font-size:13px;cursor:pointer}.archive-reset:hover{color:var(--blue)}.archive-results-bar{display:flex;align-items:center;justify-content:space-between;margin:24px 0 15px;font-size:12px;color:#8b98af}.archive-results-bar>p{font-weight:500;color:#5c6c88}.paper-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.paper-tile{background:white;border:1px solid var(--line);border-radius:13px;padding:22px;transition:border-color .2s,box-shadow .2s}.paper-tile:hover{border-color:#abc1f9;box-shadow:0 7px 20px #132e6308}.paper-tile-top{display:flex;justify-content:space-between;gap:10px;align-items:flex-start}.paper-year{font-size:22px;line-height:1.15;letter-spacing:-.04em;font-weight:500;color:#8a9fbe}.paper-year small{display:block;font-size:12px;color:#a3afc0;font-weight:400;letter-spacing:0;margin-top:4px}.paper-tile .n-tag{font-size:12px;padding:5px 6px;letter-spacing:.04em}.current-tag{color:#4269b4;border-color:#dbe6fc;background:#f2f6ff}.paper-tile h3{font-size:23px;letter-spacing:-.04em;line-height:1.35;font-weight:600;margin-top:22px}.paper-tile h3 span{font-size:13px;color:#6e86b3;border:1px solid #dce5f5;border-radius:5px;padding:2px 5px;vertical-align:middle;margin-left:3px;letter-spacing:0}.paper-tile>p{font-size:12px;color:#8492aa;margin-top:7px}.paper-tile-foot{display:flex;align-items:center;justify-content:space-between;gap:8px;border-top:1px solid #eaf0f8;margin-top:23px;padding-top:17px}.paper-tile-foot button{border:0;background:none;padding:0;font-size:13px;cursor:pointer;gap:8px}.paper-tile-foot>span{font-size:12px;color:#91a0b8;white-space:nowrap}.archive-more{display:flex;margin:26px auto}.archive-note{font-size:13px;line-height:1.7;color:#8a97ad;margin:25px 0;max-width:760px}.archive-empty{padding:50px 24px;text-align:center;grid-column:1/-1;background:white;border:1px dashed #d5e0f4;border-radius:14px}.archive-empty>span{font-size:35px;color:#7ea2fc}.archive-empty h3{font-size:18px}.archive-empty p{font-size:14px;color:var(--muted);margin:8px 0 22px}.paper-reader{max-width:none;width:min(1140px,94vw);height:92dvh;max-height:1000px;border:1px solid #d4dff2;padding:0;border-radius:16px;color:var(--ink);overflow:hidden;background:#f1f4fb;box-shadow:0 25px 100px #081c5140}.paper-reader[open]{display:flex;flex-direction:column}.paper-reader::backdrop{background:#071634b3;backdrop-filter:blur(6px)}.reader-header{display:flex;justify-content:space-between;align-items:center;gap:20px;padding:18px 23px;background:white;border-bottom:1px solid var(--line)}.reader-header h2{font-size:17px;margin-top:4px;letter-spacing:-.02em}.reader-header .n-kicker{font-size:12px}.reader-close{background:#f1f4fa;width:35px;height:35px;border:1px solid var(--line);border-radius:9px;font-size:25px;line-height:1;flex:none}.reader-toolbar{display:flex;align-items:center;justify-content:space-between;gap:15px;padding:12px 23px;background:white}.reader-tabs{background:#edf2fc;padding:4px;border-radius:9px;display:flex;gap:3px}.reader-tabs button{border:0;background:transparent;padding:8px 13px;font-size:13px;border-radius:6px;color:#7183a2;cursor:pointer}.reader-tabs button[aria-pressed=true]{background:white;color:var(--blue);box-shadow:0 1px 4px #13255010}.reader-tabs button:disabled{opacity:.45;cursor:not-allowed}.reader-toolbar a{font-size:13px}.paper-reader iframe{width:100%;flex:1;border:0;background:white}.reader-note{font-size:12px;padding:8px 20px;color:#73829d;text-align:center}@keyframes orbit-breathe{50%{transform:rotate(-18deg) scale(1.05)}}
@media(max-width:1150px){.lab-hero{padding:29px;grid-template-columns:1.2fr 1fr}.lab-planet{width:145px;height:145px}.lab-rays{width:250px}.lab-next{flex-wrap:wrap}.lab-next>div{flex-basis:100%}.paper-grid{grid-template-columns:repeat(2,1fr)}.paper-tile .n-tag{font-size:12px}.paper-tile-foot>span{font-size:12px}.lesson-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:800px){.lab-hero{grid-template-columns:1fr}.lab-orbit{position:absolute;right:-90px;top:0;width:280px;opacity:.35;z-index:-1}.lab-hero-text>p:not(.n-kicker){max-width:400px}.archive-filters{gap:12px;padding:18px;grid-template-columns:1fr 1fr}.archive-reset{grid-column:2;text-align:right;min-height:25px}.archive-intro{padding:20px;gap:14px}.archive-total{display:none}.paper-tile{padding:19px}.paper-tile-foot{align-items:flex-start;flex-direction:column;gap:9px}}
@media(max-width:650px){.lab-hero{padding:25px}.lab-hero h2{font-size:34px}.lab-hero .n-kicker{font-size:12px}.lab-hero-text>p:not(.n-kicker){font-size:14px;max-width:300px}.lab-actions{gap:14px}.notes-heading .n-tag{display:none}.lesson-grid{gap:12px}.lesson-tile{padding:18px}.lesson-tile h3{font-size:16px}.lesson-tile>p{font-size:13px}.lesson-tile-foot{font-size:12px}.lesson-symbol{font-size:24px}.lab-next{padding:20px}.lab-next .n-button{width:100%;justify-content:space-between}.archive-emblem{display:none}.archive-intro p{font-size:13px}.paper-grid{gap:12px}.paper-tile{padding:17px}.paper-tile-top{flex-direction:column;gap:10px}.paper-year{font-size:21px}.paper-year small{display:inline;margin-left:7px}.paper-tile .n-tag{font-size:12px}.paper-tile h3{font-size:21px;margin-top:17px}.paper-tile>p{font-size:12px}.paper-tile-foot>span{font-size:12px}.paper-reader{width:96vw;height:94dvh;border-radius:12px}.reader-header{padding:14px}.reader-header h2{font-size:14px}.reader-toolbar{padding:10px;gap:8px}.reader-tabs button{padding:8px;font-size:12px}.reader-toolbar a{font-size:12px;white-space:nowrap}}
/* Release navigation: compact topic discovery and transparent review scope. */
.review-guide{margin:0 0 22px;border:1px solid #c8d9f2;border-radius:16px;background:#f2f7ff;color:#405371;padding:14px 18px;max-width:900px;font-size:14px}
.review-guide summary{cursor:pointer;display:flex;align-items:center;gap:12px;list-style:none;font-weight:550}
.review-guide summary:after{content:'+';margin-left:auto;font-size:20px;color:#3164b8}
.review-guide[open] summary:after{content:'−'}
.review-guide p{line-height:1.7;margin:14px 0 2px;max-width:78ch}
.review-badge{display:inline-flex;align-items:center;border-radius:100px;background:#e0edff;color:#204f98;border:1px solid #bbd2f5;padding:5px 11px;font-size:12px;font-weight:650;white-space:nowrap}
.topic-search-label{display:block;font-size:14px;font-weight:600;margin:2px 0 8px;color:#405371}
#topic-search{width:100%;border:1px solid #c4d2e8;border-radius:12px;padding:13px 15px;background:#f7faff;color:#132a4c;font:inherit;margin-bottom:18px}
#topic-search:focus{outline:3px solid #bbd5ff;outline-offset:2px}
.topic-group[hidden],.subtopic-label[hidden],.study-selected[hidden]{display:none!important}
.selected-topics{display:flex;flex-wrap:wrap;gap:7px;margin:12px 0;max-height:180px;overflow:auto}
.selected-topic{font:inherit;font-size:14px;line-height:1.45;text-align:left;color:#285597;background:#edf4ff;border:1px solid #ccddf5;border-radius:10px;padding:7px 9px;cursor:pointer}
.selected-topic span{margin-left:5px;font-size:16px}
.selected-topic:hover{background:#dfeeff;border-color:#8fb4ec}
.selected-topics:empty{display:none}
.study-selected{display:flex;align-items:center;justify-content:space-between;gap:8px;color:#285597;font-size:14px;line-height:1.5;padding:12px 0 16px;text-decoration:none}
.study-selected:hover{text-decoration:underline}
.practice-review-note{display:flex;gap:10px;align-items:center;flex-wrap:wrap;font-size:13px;color:#526783;margin:0 0 12px}
.archive-note strong{display:block;margin-bottom:6px;color:#405371}
#search-form[aria-busy="true"] .primary-button{background:linear-gradient(100deg,#234e99,#4a85dc,#234e99);background-size:200% 100%;animation:pack-load 1.4s linear infinite}
@keyframes pack-load{to{background-position:-200% 0}}
@media(prefers-reduced-motion:reduce){#search-form[aria-busy="true"] .primary-button{animation:none}}
body[data-motion="off"] #search-form[aria-busy="true"] .primary-button{animation:none}