:root{--ink:#182c40;--accent:#126b61;--border:#dce4e5;--muted:#596977;color:var(--ink);background:#f6f7f4;line-height:1.5;font-family:Segoe UI,Arial,sans-serif}body{min-height:100vh}[hidden]{display:none!important}a{color:#126b61;text-underline-offset:4px}a:hover{text-decoration-thickness:2px}button,.button{background:var(--accent);border-radius:10px;font-weight:600;line-height:1.4;transition:background .15s,box-shadow .15s;min-height:44px}button:hover,.button:hover{background:#0b514a;color:white}button.secondary{background:#edf2f0;color:#23554f;border:1px solid #d7e3dd}button.secondary:hover{background:#dfece5}button.quiet{background:transparent;color:#596977}button:disabled{cursor:wait}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid #42a99a;outline-offset:4px}input:focus,textarea:focus,select:focus{outline:3px solid #bfe2d8;border-color:#126b61}input,textarea,select{border-color:#b8c7cc;border-radius:8px;line-height:1.5}input:not([type=checkbox]),select{min-height:44px}input:disabled,textarea:disabled,select:disabled{color:#5b6770;background:#f3f5f4;opacity:1}label{font-weight:600;font-size:14px;color:#384d5c}textarea{resize:vertical}header{background:#fff;color:var(--ink);padding:19px max(24px,calc((100vw - 1140px)/2));border-bottom:1px solid var(--border);gap:24px}header .brand{color:var(--ink);padding-left:44px;position:relative}header .brand:before{content:'';position:absolute;left:0;top:5px;width:30px;height:34px;background:url('/favicon.svg') center/contain no-repeat}header strong{font-size:25px;letter-spacing:-.6px}header small{color:var(--muted);font-size:12px;letter-spacing:.2px}header nav{gap:22px}header nav a{color:#435964;text-decoration:none;font-weight:600;font-size:14px}header nav a[aria-current=page]{color:var(--accent)}header nav .button{color:white}header nav button{font-size:14px;padding:9px 14px}header .account-link{max-width:180px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}main{max-width:1190px;margin:36px auto 70px;padding:0 28px}main:focus{outline:none}h1{font-size:44px;font-weight:500;letter-spacing:-1.3px;line-height:1.15;margin:12px 0 18px}h2{font-size:23px;line-height:1.3}h3{line-height:1.4}.eyebrow{color:var(--accent);letter-spacing:1.6px;font-size:12px}.muted{color:var(--muted)}.card{border-color:var(--border);border-radius:16px;padding:28px;box-shadow:0 3px 12px #192c3e03}.badge{background:#eaf1ed;color:#386258;font-size:12px;font-weight:600;padding:6px 11px}.library-heading{margin:24px 0 24px;align-items:flex-end}.library-heading h1{max-width:680px;font-size:48px;line-height:1.12}.library-heading .muted{max-width:640px;margin-bottom:0}.library-tools{display:flex;justify-content:space-between;gap:20px;align-items:flex-end;margin:30px 0 20px;padding-top:22px;border-top:1px solid var(--border)}.search-field{display:block;width:min(100%,430px);margin:0}.search-field span{display:block;margin-bottom:8px}.search-field input{display:block;width:100%;margin-top:6px;background:#fff}.library-tools p{font-size:14px;white-space:nowrap;margin-bottom:12px}.book-grid{grid-template-columns:repeat(auto-fill,minmax(305px,1fr));gap:24px;align-items:start}.book-card{max-width:none;border-color:var(--border);border-radius:16px;box-shadow:0 5px 18px #172c3b05}.book-card:hover{border-color:#79aca0;box-shadow:0 12px 25px #162b3b0b;text-decoration:none}.book-cover{height:290px;background:#e9eeea;padding:25px}.cover-image{filter:drop-shadow(0 8px 8px #15293b29)}.book-card-copy{padding:23px 26px 26px}.book-card-copy h2{font-size:30px;font-weight:500;letter-spacing:-.6px}.book-card-copy .muted{font-size:14px;line-height:1.7;margin-bottom:19px}.book-card-copy .eyebrow{font-size:11px}.book-count{display:block;font-size:13px;margin-top:13px;color:var(--muted)}.cover-fallback{background:#1e4743}.book-intro{gap:48px;margin-top:28px}.book-intro h1{font-size:52px;font-weight:500}.book-intro .large{background:#e9eeea;height:410px}.description{font-size:16px;line-height:1.85}.breadcrumb{font-size:14px;text-decoration:none}.breadcrumb:before{content:'←';padding-right:8px}.continue-card{background:#193c39;color:white;display:flex;align-items:center;justify-content:space-between;gap:28px;border-radius:16px;padding:25px 30px;margin:26px 0}.continue-card .eyebrow{color:#aad5c7;margin:0 0 7px}.continue-card h2{font-family:Georgia,serif;font-size:28px;font-weight:400;margin:0}.continue-card p:last-child{color:#c3d6d1;margin:8px 0 0;font-size:14px}.continue-card .button{background:#e0ede2;color:#17473d;white-space:nowrap}.continue-card .button:hover{background:white}.course-progress{display:flex;gap:40px;align-items:center;justify-content:space-between;background:#edf3ed}.course-progress>div:first-child{flex:1}.course-progress strong{font-size:17px}.course-progress .eyebrow{margin-top:0}progress{accent-color:#126b61;width:100%;height:8px;border:0;border-radius:8px;display:block;margin-top:15px;background:#cfddd4}progress::-webkit-progress-bar{background:#cfddd4;border-radius:8px}progress::-webkit-progress-value{background:#126b61;border-radius:8px}.progress-score{min-width:135px}.progress-score>strong{font-size:28px;display:block}.progress-score small{font-size:15px;font-weight:400;color:#61736b}.progress-score span{color:#50655c;font-size:13px}.overview-section{margin:25px 0}.overview-section:first-of-type{margin-top:18px}.overview-lesson{border-color:var(--border);border-radius:6px;padding:17px 12px}.overview-lesson:hover,.lesson-link:hover{background:#eff4ef}.overview-lesson span{color:var(--muted)}.layout{grid-template-columns:250px minmax(0,1fr);gap:26px}.mobile-course{position:sticky;top:20px;align-self:start;min-width:0}.mobile-course summary{display:none}.mobile-course .course-tree{position:static}.course-tree{padding:21px}.course-home{color:var(--ink);font-family:Georgia,serif;font-size:21px;line-height:1.3}.tree-section{border-color:var(--border)}.tree-section h3{font-size:11px;color:#687976}.lesson-link{color:#435f58;font-size:14px;gap:10px;padding:12px 9px;align-items:flex-start}.lesson-link small{white-space:normal;min-width:40px;text-align:right;font-size:11px}.lesson-link.selected{background:#e4eee7;color:#155c4c}.lesson-heading{margin-bottom:22px}.lesson-heading h1{font-size:38px;margin:8px 0}.step-nav{gap:10px;grid-template-columns:repeat(auto-fit,minmax(100px,1fr))}.step-tab{background:white;border-color:var(--border);color:#50675e;font-size:14px;border-radius:10px;padding:13px 16px}.step-tab.current{background:#193c39;color:white;border-color:#193c39}.step-tab.complete:not(.current){background:#e9f2e9;border-color:#93b9a7}.step-tab small{font-size:12px}.step-title{font-size:27px;font-family:Georgia,serif;font-weight:500;margin-top:22px;letter-spacing:-.3px}.task-prompt{font-size:16px;line-height:1.85}.gap{font-size:16px;line-height:3.4;margin:16px 0}.gap input{width:155px;margin:0 7px;padding:8px 11px;min-height:41px}.answer-note{display:inline-block;font-size:11px;line-height:1.4;color:#176347;font-weight:600;margin:0 7px 0 -2px}.error-note{color:#a13333}.correct{background:#edf8f0;border-color:#3f9367}.incorrect{background:#fff1f0;border-color:#b54848}.match{grid-template-columns:140px minmax(0,1fr);gap:16px}.match label{font-size:15px;margin:0}.match select{font-size:14px}.action-bar{border-top:1px solid var(--border);padding-top:20px;margin-top:24px}.save-status{font-size:12px;color:#587168;margin:10px 0 20px;padding:7px 0;min-height:24px}.save-status[data-state=dirty]{color:#8d6218}.save-status[data-state=error]{color:#a13333}.check-result{padding:20px;border-radius:8px}.check-result small{color:#596977}.page-navigation{font-size:14px;margin:24px 0}.feedback{background:#eaf2ec;border-color:var(--accent);border-radius:6px;font-size:15px}.draft-recovery{background:#fff5df;border:1px solid #e5c47c;border-radius:10px;padding:16px;margin:10px 0 20px;font-size:14px}.draft-recovery button{font-size:13px;min-height:36px;padding:7px 11px;margin-top:8px}.stats-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;margin:26px 0}.stat-card{background:white;border:1px solid var(--border);border-radius:13px;padding:22px 25px}.stat-card strong{font-size:32px;color:#234f45;display:block;font-weight:600}.stat-card span{color:var(--muted);font-size:14px}.review-tools{display:flex;gap:25px;align-items:flex-end;margin:25px 0}.review-tools label{margin:0;min-width:180px}.review-tools input,.review-tools select{display:block;width:100%;margin-top:8px}.review-tools label:first-child{flex:1}.review-card h2{margin:0;flex:1}.review-card .writing{padding:22px;background:#f6f8f5;border-radius:10px;margin:15px 0;font-size:16px}.review-card input[type=number]{width:140px}.review-card summary{color:var(--accent);font-weight:600;padding:8px 0}.review-card textarea{min-height:140px}.teacher-tabs{gap:25px;padding:0;border-color:var(--border);margin:25px 0}.teacher-tabs a{padding:14px 0;font-size:14px;color:var(--muted);border-bottom:3px solid transparent}.teacher-tabs .active{color:var(--accent);border-bottom-color:var(--accent)}.editor-layout{gap:24px}.lesson-editor{grid-template-columns:285px minmax(0,1fr)}.assignment-link{color:#37584f;border-color:var(--border);border-radius:5px;font-size:14px}.assignment-link.selected{background:#e9f1eb;border-left:3px solid #126b61}.assignment-link small{font-size:12px}.structure-lesson{background:#eef3ee}.builder-row{background:#f5f7f3;border-color:var(--border);padding:20px}.builder-row button{font-size:13px}.builder-table th,th{background:#ecf1ed;font-size:13px;color:#456456}th,td{border-color:var(--border)}.editor-layout .preview-card{background:#f5f7f3}.history-item{border-top:1px solid var(--border);padding:15px 0}.attempt-history summary{cursor:pointer;font-weight:600;color:#456456}.account-page{max-width:650px}.account-page input{width:100%}.account-page h2{margin-top:32px;font-size:20px}.account-page .muted{font-size:14px}.account-page button{margin-top:15px}.student-table{min-width:670px}.student-table td{padding:22px 12px}.student-table small{display:block;color:var(--muted);margin-top:5px;font-size:12px}.student-course{display:flex;flex-direction:column;gap:5px;font-size:13px}.student-course+.student-course{margin-top:16px}.student-course span{color:var(--muted)}.connection-banner{padding:12px 25px;background:#fff2d8;color:#835815;text-align:center;font-size:14px}#notice{box-shadow:0 8px 32px #182c4030;z-index:20;font-size:14px;line-height:1.6}.skip-link{position:fixed;top:-80px;left:12px;z-index:100;background:#193c39;color:white;padding:12px 20px;border-radius:8px}.skip-link:focus{top:12px}.loading-page,.page-error{text-align:center;padding-top:100px}.page-error .row{justify-content:center}.loading-mark{background:#193c39;color:white;border-radius:14px;font:36px Georgia,serif;width:64px;height:64px;display:grid;place-items:center;margin:0 auto}.auth{max-width:470px}.auth .card{margin-top:25px}.auth h1{font-size:40px}.auth>.secondary{font-size:13px;margin-top:0}.scroll{scrollbar-width:thin;scrollbar-color:#aac5ba transparent}.scroll:focus-visible{outline:3px solid #bfe2d8;outline-offset:4px}
@media(min-width:801px){.mobile-course summary{display:none}}
@media(max-width:1000px){header{padding:18px 26px}header nav{gap:14px}.library-heading h1{font-size:42px}.book-grid{grid-template-columns:repeat(auto-fill,minmax(285px,1fr))}.gap input{width:140px}.card{padding:23px}}
@media(max-width:800px){main{padding:0 18px;margin-top:25px}.layout,.editor-layout,.lesson-editor{grid-template-columns:1fr}.mobile-course{position:static;margin-bottom:4px;border:1px solid var(--border);border-radius:12px;background:white}.mobile-course summary{display:block;padding:15px 20px;font-size:14px;font-weight:600;color:var(--accent);cursor:pointer}.mobile-course summary:after{content:'⌄';float:right}.mobile-course[open] summary:after{content:'⌃'}.mobile-course .course-tree{border:0;box-shadow:none;margin:0;padding:15px 20px}.book-intro{grid-template-columns:210px minmax(0,1fr);gap:25px}.book-intro .large{height:300px}.book-intro h1{font-size:39px}.course-progress{gap:22px}.teacher-tabs{gap:20px}.overview-lesson{flex-direction:column;gap:6px}.match{grid-template-columns:1fr;gap:6px}.stats-grid{gap:10px}.stat-card{padding:18px}.stat-card span{font-size:12px}}
@media(max-width:600px){header{padding:16px 18px;gap:18px;flex-wrap:wrap}header .brand{padding-left:38px}header .brand:before{width:27px;height:31px}header strong{font-size:23px}header nav{width:100%;justify-content:space-between;gap:10px}header nav a,header nav button{font-size:12px}.library-heading{margin-top:12px}.library-heading h1{font-size:36px;max-width:370px}.library-heading .muted{font-size:14px}.library-tools{margin-top:24px;gap:14px}.library-tools p{font-size:12px}.book-grid{grid-template-columns:1fr}.book-cover{height:280px}.book-card-copy h2{font-size:28px}.book-intro{grid-template-columns:1fr;gap:25px}.book-intro .large{height:320px;width:230px}.book-intro h1{font-size:40px}.book-intro .description{font-size:15px}.continue-card{flex-direction:column;align-items:flex-start;padding:23px}.course-progress{flex-wrap:wrap;padding:22px}.course-progress>div:first-child{flex-basis:100%}.course-progress .progress-score{min-width:0}.lesson-heading{align-items:center}.lesson-heading h1{font-size:30px}.lesson-heading .badge{white-space:nowrap;font-size:11px}.step-nav{grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.step-tab{padding:12px 14px}.step-title{font-size:25px}.card{padding:21px;border-radius:13px}.task-prompt{font-size:15px}.gap{font-size:15px;line-height:3.2}.gap input{width:135px;font-size:15px}.answer-note{font-size:10px;margin-left:0}.page-navigation{font-size:13px}.action-bar button{padding:11px 14px;font-size:13px}.stats-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}.stat-card{padding:14px 12px}.stat-card strong{font-size:26px}.stat-card span{font-size:11px;display:block;line-height:1.4}.review-tools{gap:16px;flex-wrap:wrap}.review-tools label{min-width:140px}.review-tools label:first-child{flex-basis:100%}.review-card h2{font-size:20px}.teacher-tabs{gap:14px;flex-wrap:wrap}.teacher-tabs a{font-size:12px;padding:11px 0}.editor-layout .row{gap:8px}.structure-lesson a{flex-direction:column}.auth h1{font-size:36px}.account-page h1{font-size:36px}#notice{left:16px;right:16px;bottom:16px;max-width:none}.review-tools button{font-size:13px}.book-card-copy{padding:22px}.book-count{font-size:12px}.account-link{max-width:115px!important}}
.book-grid:has(>.book-card:only-child){grid-template-columns:1fr}.book-grid>.book-card:only-child{display:grid;grid-template-columns:270px minmax(0,1fr);max-width:900px}.book-grid>.book-card:only-child .book-cover{height:300px}.book-grid>.book-card:only-child .book-card-copy{padding:36px 40px;align-self:center}.book-grid>.book-card:only-child h2{font-size:36px}.book-grid>.book-card:only-child .clamp{-webkit-line-clamp:3;max-width:500px}.book-grid>.book-card:only-child .book-card-copy:after{content:'Explore course →';display:block;margin-top:20px;color:#126b61;font-size:14px;font-weight:600}
@media(max-width:600px){.book-grid>.book-card:only-child{grid-template-columns:1fr}.book-grid>.book-card:only-child .book-cover{height:260px}.book-grid>.book-card:only-child .book-card-copy{padding:23px 25px}.book-grid>.book-card:only-child h2{font-size:30px}}
@media(prefers-reduced-motion:reduce){:root{scroll-behavior:auto}*,*::before,*::after{transition:none!important}}

.leave-dialog{position:fixed;inset:0;z-index:100;background:#162c4166;display:grid;place-items:center;padding:20px}.leave-dialog section{background:white;padding:30px;border-radius:16px;box-shadow:0 15px 60px #172d4150;width:min(100%,460px)}.leave-dialog p{color:#596977;font-size:15px;line-height:1.7}.leave-dialog .row{margin-top:25px}.leave-dialog button{font-size:14px}

main:has(.teacher-tabs) .book-grid>.book-card:only-child .book-card-copy:after{content:'Edit book →'}

.library-heading{margin:0 0 20px;align-items:center}.library-heading h1{font-size:38px;margin:0;max-width:none}.library-tools{margin:0 0 22px;padding-top:0;border-top:0}@media(max-width:600px){.library-heading{margin-top:0}.library-heading h1{font-size:30px}}