@media(min-width:1441px){.home-world,.auth-world{max-width:1680px;margin:auto}.home-copy{padding-top:44px}.container{width:min(calc(100% - 112px),var(--content-max))}}
@media(max-width:1100px){.nav-links{gap:20px}.site-header{padding:0 16px;gap:12px}.brand{font-size:18px}.brand .icon{width:28px}.nav-actions .btn-sm{padding:8px 13px}.auth-world{padding-top:95px}.activity-card{padding:15px 16px 0}.activity-card h3{font-size:16px}.book-grid{grid-template-columns:1fr 1fr}.continue-card{grid-template-columns:32% 1fr}.continue-card .checklist{display:none}.utility-layout{grid-template-columns:190px 1fr}.word-cell{font-size:18px}.home-copy .eyebrow{font-size:9px}.source-icon{max-width:40px}.auth-split .auth-heading h1{font-size:40px}}
@media(max-width:820px){.container{width:calc(100% - 40px)}.site-header{width:calc(100% - 32px)}.nav-links{display:none}.mobile-menu{display:grid}.nav-actions .desktop-login{display:none}.nav-links.open{display:flex;position:absolute;top:calc(var(--header-h) + 8px);left:0;right:0;padding:16px 20px;border:1px solid var(--line);border-radius:16px;background:white;flex-direction:column;align-items:stretch;gap:1px;box-shadow:var(--shadow-panel)}.nav-links.open a{padding:11px 0}.home-copy{width:70%}.home-copy h1{font-size:38px}.home-copy p{font-size:13px}.activity-card,.activity-card:nth-child(n+5){grid-column:span 6;min-height:220px}.activity-card:last-child{grid-column:span 12;min-height:150px}.activity-card:last-child .art{max-width:40%;align-self:flex-end;max-height:105px}.activity-card:last-child p{max-width:50%}.auth-world .art-rail{opacity:.65;width:27%}.auth-split .auth-card{margin-inline:auto;width:min(440px,calc(100% - 40px))}.auth-split .auth-heading{text-align:center;max-width:650px;margin:auto auto 24px;padding:0 20px}.auth-world{min-height:770px}.world-banner{grid-template-columns:50% 50%;min-height:240px}.world-banner .copy{padding:27px}.world-banner h2{font-size:23px}.world-banner img{height:245px}.benefits{gap:5px;padding:25px 15px}.benefit{padding:10px}.benefit p{font-size:12px}.unit-grid .activity-card{grid-column:span 6}.unit-grid .activity-card:nth-child(7){grid-column:span 12}.unit-grid .activity-card:nth-child(7) .art{right:45px;width:210px}.unit-library{grid-template-columns:repeat(2,1fr)}.utility-layout{grid-template-columns:1fr}.utility-nav{flex-direction:row;flex-wrap:wrap;margin-bottom:8px}.utility-nav a{font-size:12px;padding:8px 10px}.utility-nav .icon{width:18px;height:18px}.metrics{gap:10px}.metrics .panel{padding:18px}.metric .value{font-size:34px}.game-two-col{grid-template-columns:1fr}.board-demo{max-width:500px;margin:auto;width:100%}.word-layout{grid-template-columns:1fr 220px;gap:15px}.odd-options{grid-template-columns:repeat(2,1fr)}.odd-options .option{min-height:200px}.footer{flex-wrap:wrap}.screen-index{grid-template-columns:repeat(2,1fr)}}
@media(max-width:540px){body{font-size:15px}.container{width:calc(100% - 32px)}.site-header{width:calc(100% - 20px);height:58px;padding:0 12px;border-radius:0 0 16px 16px}.brand{font-size:17px}.brand .icon{width:25px;height:29px}.nav-actions{gap:6px}.nav-actions>.btn-sm{display:none}.nav-actions .icon-button{width:40px;height:40px}.teacher-menu{max-width:85px;overflow:hidden;text-overflow:ellipsis;font-size:12px}.home-copy{width:86%;padding-top:36px;padding-bottom:12px}.home-copy h1{font-size:37px}.home-copy .eyebrow{font-size:8px;letter-spacing:.22em}.home-copy p{font-size:14px;line-height:1.5}.home-world .rail{width:26%;opacity:.6}.home-scene{width:126%;max-width:none;margin-left:-13%}.section{padding:30px 0}.section-heading h2{font-size:27px}.section-heading p{font-size:14px}.activity-grid{gap:12px}.activity-card,.activity-card:nth-child(n+5){grid-column:span 12;min-height:180px;padding:18px}.activity-card .art,.activity-card:nth-child(n+5) .art{position:absolute;right:6px;bottom:4px;max-width:49%;height:90px;max-height:110px;object-fit:contain}.activity-card h3{font-size:19px;max-width:68%}.activity-card p{max-width:55%;font-size:13px}.activity-card .source-icon{width:35px;height:35px}.activity-card .state{margin-top:15px}.world-banner{display:block;margin-top:16px;border-radius:34px 34px 0 0;min-height:0}.world-banner .copy{padding:27px 28px 0}.world-banner h2{font-size:27px}.world-banner img{height:200px;max-width:100%;object-fit:cover;object-position:50% 55%}.world-banner .btn{margin-bottom:10px}.footer{padding:22px 25px;gap:17px}.footer-links{gap:15px;line-height:2}.footer .note{display:none}.auth-world{padding-top:92px;min-height:0;padding-bottom:45px}.auth-world .art-rail{width:38%;height:470px;opacity:.27}.auth-heading{padding:0 24px;margin-bottom:24px}.auth-heading h1{font-size:37px}.auth-heading p{font-size:14px}.auth-card{padding:24px;width:calc(100% - 36px);max-width:430px;border-radius:23px}.auth-card .product-summary{gap:14px;padding:13px}.auth-card h3{font-size:18px}.auth-split .auth-heading h1{font-size:36px}.auth-card .mini-cover{width:76px;height:104px}.benefits{grid-template-columns:1fr;padding:18px 30px;gap:4px}.benefit{text-align:left;display:grid;grid-template-columns:52px 1fr;gap:0 15px}.benefit .badge-circle{grid-row:span 2;margin:0;width:46px;height:46px}.benefit h3{margin:0 0 4px;font-size:16px}.benefit p{font-size:13px}.screen-world{padding-top:90px}.screen-world::before,.screen-world::after{width:35%;height:400px;opacity:.34}.page-intro{margin:18px 0 27px}.page-intro h1{font-size:36px}.page-intro p{font-size:14px}.breadcrumbs{font-size:11px;gap:7px;margin-bottom:18px}.breadcrumbs .back-label{display:none}.unit-progress{gap:12px;padding:12px 14px;font-size:12px}.unit-grid{margin-top:25px}.unit-grid .activity-card{grid-column:span 12;min-height:190px}.unit-grid .activity-card:nth-child(7){min-height:185px;padding:18px}.unit-grid .activity-card:nth-child(7) .art{right:8px;width:160px;height:93px}.unit-grid .activity-card:nth-child(7) .source-icon{float:none;width:35px;height:35px}.unit-grid .activity-card:nth-child(7) h3{margin:6px 0}.book-grid{grid-template-columns:1fr}.book-card{min-height:210px;padding:24px}.add-book{min-height:160px}.continue-card{grid-template-columns:1fr;padding:20px;gap:19px}.continue-card>img{height:160px}.unit-library{grid-template-columns:1fr}.unit-tile{min-height:170px;position:relative;padding:22px 105px 22px 22px}.unit-tile .unit-art{position:absolute;right:17px;top:30px;width:65px;height:65px}.unit-tile h3{font-size:21px}.panel{padding:22px;border-radius:21px}.metrics{grid-template-columns:1fr}.metric{display:flex;gap:16px;align-items:center}.metric .value{margin:0;order:-1;min-width:70px}.utility-nav{gap:4px}.utility-nav a{padding:8px;font-size:12px}.utility-nav .icon{display:none}.word-layout{grid-template-columns:1fr;gap:20px}.word-grid{padding:7px;gap:3px}.word-cell{font-size:17px;border-radius:5px;min-height:31px}.word-list{display:grid;grid-template-columns:1fr 1fr;margin-bottom:14px;gap:0 8px}.word-list li{font-size:13px;min-height:37px;gap:8px}.activity-topline{gap:12px;flex-wrap:wrap}.question-title{font-size:23px}.option{font-size:14px;padding:13px;min-height:55px}.odd-options{gap:10px}.odd-options .option{min-height:176px;padding:10px}.odd-options img{height:106px}.activity-actions{gap:10px;flex-wrap:wrap}.activity-actions .btn{flex:1;padding:12px 16px;white-space:nowrap;font-size:14px}.video-player{border-width:4px;border-radius:14px}.video-play{width:62px;height:62px}.video-play .icon{width:26px;height:26px}.video-controls{padding:9px;gap:9px;font-size:10px}.video-controls .icon{width:17px;height:17px}.video-outcomes{grid-template-columns:1fr;text-align:left;gap:18px}.video-outcomes>div{display:grid;grid-template-columns:50px 1fr;gap:0 14px}.video-outcomes .badge-circle{grid-row:span 2;width:45px;height:45px;margin:0}.video-outcomes h3{font-size:16px;margin:0 0 5px}.video-outcomes p{margin:0}.test-facts{gap:10px}.test-fact{padding:13px;font-size:12px}.tug-art{height:170px}.scoreboard{gap:50px}.team strong{font-size:32px}.practice-tabs{gap:7px}.practice-tabs button{font-size:11px;padding:7px 11px;min-height:38px}.completion-grid{grid-template-columns:1fr}.screen-index{grid-template-columns:1fr}.demo-label{font-size:9px;max-width:calc(100% - 16px)}.board-demo{padding:13px}.board-cell{border-radius:10px}.score-ring{width:156px;height:156px}.is-focus .page-intro h1{font-size:28px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{transition:none!important;animation-duration:.01ms!important;animation-iteration-count:1!important}.btn:hover,.activity-card:hover{transform:none}}
@media print{.header-wrap,.nav-actions,.demo-label,.world-banner,.footer,.activity-actions{display:none!important}body{background:#fff}.screen-world{padding-top:0}.screen-world::before,.screen-world::after{display:none}.panel{box-shadow:none;border-color:#aaa}.container{width:100%}}
@media(min-width:1681px){.home-world .rail{height:calc(100% - var(--header-h) - 634px)}}
@media(max-width:540px){.home-world .rail{height:calc(100% - var(--header-h) - 47.53vw)}.world-banner img{mask-image:linear-gradient(180deg,transparent,#000 13%)}.auth-world::before{display:none}}

@media(max-width:1100px){.nav-links{gap:16px}.nav-links a{font-size:12px}}
@media(max-width:1023px){
 .unit-lab .activity-card{grid-column:span 6}
 .unit-hero{min-height:500px}
 .unit-robot{width:170px;height:220px}
}
@media(max-width:767px){
 .container{width:calc(100% - 32px)}
 .unit-hero{min-height:460px;padding:90px 0 120px}
 .unit-hero .breadcrumbs{font-size:11px;margin-bottom:20px}
 .unit-heading h1{font-size:36px;max-width:440px;margin:0 auto 14px}
 .unit-heading>p{font-size:14px;max-width:280px}
 .unit-heading .unit-choice{font-size:12px;max-width:250px}
 .unit-heading .unit-progress{max-width:330px;padding:12px 16px;margin-top:18px}
 .unit-hero::before,.unit-hero::after{top:280px;width:32%;opacity:.5}
 .unit-robot{left:10px;width:98px;height:112px;bottom:0}
 .unit-lab .activity-card,.unit-lab .activity-card:nth-child(7){grid-column:1/-1;min-height:240px;padding:20px 20px 132px}
 .unit-lab .activity-card .source-icon,.unit-lab .activity-card:nth-child(7) .source-icon{top:20px;left:20px;width:42px;height:42px}
 .unit-lab .activity-copy,.unit-lab .activity-card:nth-child(7) .activity-copy{margin-left:60px;max-width:none}
 .unit-lab .activity-card h3,.unit-lab .activity-card:nth-child(7) h3{font-size:19px;margin-top:0}
 .unit-lab .activity-card .art,.unit-lab .activity-card:nth-child(7) .art{width:100%;height:126px;left:0;right:auto;object-fit:cover;mask-image:linear-gradient(180deg,transparent,#000 25%)}
 .unit-lab .activity-card:nth-child(7) .state:not(.sr-only){left:18px;right:auto}
 .word-layout{grid-template-columns:1fr}
 .unit-lab .world-banner .copy{padding-top:28px}
 .nav-actions .icon-button{width:44px;height:44px}
 .progress-unit{padding:16px}.progress-unit th,.progress-unit td{padding:12px 6px;font-size:12px}
 .progress-unit .pill{padding:5px;font-size:11px}.progress-unit .table-scroll{max-width:100%}
 .question-nav button{width:44px;height:44px}
}
@media(min-width:1920px){
 .container{max-width:1440px}.icon-button,.btn,.btn-sm,.nav-links a,.question-nav button{min-height:56px}.icon-button,.question-nav button{min-width:56px}
 .site-header{height:76px}.unit-lab .activity-card{min-height:285px}.unit-lab .activity-card .art{height:160px}.unit-hero{min-height:565px}
}

@media(max-width:820px){.nav-links.open .mobile-account{display:flex}}
@media(max-width:767px){.unit-hero::before{mask-image:linear-gradient(180deg,transparent,#000 28%)}.unit-hero::after{mask-image:linear-gradient(180deg,transparent,#000 28%)}}

/* Card roles are explicit so changing a link never changes its artwork crop. */
@media(max-width:1023px){.unit-lab .activity-card--standard{grid-column:span 6}.unit-lab .activity-card--featured{grid-column:1/-1}}
@media(max-width:820px){.home-features .activity-card--compact,.home-features .activity-card--wide{grid-column:span 6;min-height:220px}.home-features .activity-card--wide:last-child{grid-column:span 12;min-height:150px}}
@media(max-width:767px){.unit-lab .activity-card--standard,.unit-lab .activity-card--featured{grid-column:1/-1;min-height:240px;padding:20px 20px 132px}.unit-lab .activity-card--featured .source-icon{top:20px;left:20px;width:42px;height:42px}.unit-lab .activity-card--featured .activity-copy{margin-left:60px;max-width:none}.unit-lab .activity-card--featured h3{font-size:19px}.unit-lab .activity-card--featured .art{width:100%;height:126px;left:0;right:auto;object-fit:contain}}
@media(max-width:540px){.home-features .activity-card--compact,.home-features .activity-card--wide,.home-features .activity-card--wide:last-child{grid-column:span 12;min-height:180px}.home-features .activity-card .art{object-fit:contain;object-position:right bottom}}
@media(max-width:767px){.chapter-picker{grid-template-columns:1fr;gap:14px;margin-top:20px;padding:16px}.chapter-picker select{height:52px}.selected-chapter{align-items:flex-start;flex-direction:column;gap:2px}.content-panel{padding:18px;border-radius:17px}.video-stage{padding:7px}.question-options{grid-template-columns:1fr}.question-bank-card h2{font-size:20px}}

@media(max-width:820px){.book-overview{grid-template-columns:155px minmax(0,1fr);gap:22px;padding:22px}.book-cover-stage>img,.book-cover-fallback{height:205px}.book-overview .chapter-picker{grid-template-columns:1fr;gap:12px}.unit-activities-heading{align-items:flex-start}.unit-activities-heading .selected-chapter{text-align:left}}
@media(max-width:560px){.unit-lab .unit-hero .breadcrumbs{margin-bottom:12px}.book-overview{grid-template-columns:1fr;gap:18px;padding:18px;border-radius:23px;text-align:center}.book-cover-stage{width:145px;margin:auto;padding:7px}.book-cover-stage>img,.book-cover-fallback{height:190px}.book-overview-copy>.eyebrow{margin-bottom:5px}.book-overview-copy h1{font-size:32px}.book-facts{justify-content:center}.book-guidance{font-size:14px}.book-overview .chapter-picker{text-align:left}.unit-availability{text-align:left}.unit-chip-list{justify-content:center}.unit-activities-heading{display:block;margin-top:8px;text-align:center}.unit-activities-heading .selected-chapter{margin-top:12px;text-align:center}}
@media(max-width:900px){.library-add-panel{grid-template-columns:1fr}.platform-school-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:600px){.site-messages{top:68px;right:16px}.library-heading,.platform-heading,.school-detail-heading{align-items:flex-start;flex-direction:column}.library-add-panel{padding:20px;gap:20px}.library-isbn-control{grid-template-columns:1fr}.library-isbn-control .btn{width:100%}.platform-school-grid{grid-template-columns:1fr}.platform-form-grid{grid-template-columns:1fr}.platform-form-grid .field-wide{grid-column:auto}.platform-form-actions{flex-direction:column-reverse}.platform-form-actions .btn{width:100%}.credential-card{width:100%;min-width:0}.admin-book-row{align-items:flex-start;flex-direction:column}.admin-book-row form,.admin-book-row button{width:100%}}
@media(max-width:900px){.library-page .screen-world>.container{width:min(calc(100% - 40px),1180px)}.library-books-shell{padding:22px}.library-book-grid{grid-template-columns:1fr}}
@media(max-width:540px){.library-page .screen-world>.container{width:calc(100% - 24px)}.library-page .screen-world::before,.library-page .screen-world::after{display:none}.library-books-shell{padding:16px;border-radius:22px}.library-book-grid .library-book-card{grid-template-columns:92px minmax(0,1fr);gap:16px;min-height:190px;padding:18px}.library-book-grid .library-book-card .mini-cover{width:92px;height:130px;padding:8px}.library-book-grid .library-book-card .mini-cover strong{font-size:14px}.library-book-copy h2{font-size:19px}.library-book-copy .btn{width:100%;padding-inline:14px}.library-section-heading{align-items:center}}
@media(max-width:540px){.shared-page-scene img{height:270px;object-position:center center}.shared-page-scene+.world-banner{border-radius:0}}
@media(max-width:820px){.home-world{grid-template-rows:330px auto}.home-copy{align-self:center;padding:18px 0;transform:scale(.92)}}
@media(max-width:540px){.home-world{grid-template-rows:390px auto}.home-copy{align-self:start;padding-top:36px;padding-bottom:18px;transform:none}.home-scene{margin-top:0}}
@media(min-width:1681px){.home-world .rail{height:calc(100% - var(--header-h) - 634px + 6px)}}
@media(max-width:540px){.home-world .rail{height:calc(100% - var(--header-h) - 47.53vw + 6px)}.home-scene{top:-6px;margin-bottom:-6px}}
@media(max-width:540px){.nav-signout .btn{width:40px;height:40px;min-height:40px;padding:0;border-radius:50%}.nav-signout .btn span{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap}}