:root{--bg:#fff;--paper:#fff;--ink:#272b29;--muted:#717773;--green:#3d6b54;--dark:#2d513f;--lime:#edf3ee;--border:#e5e8e6;--soft:#f4f6f4;--serif:inherit;--shadow:none}
body{font-family:Inter,'Segoe UI',sans-serif;font-size:14px;line-height:1.65}
h1,h2,h3,h4,.brand{font-family:inherit;letter-spacing:-.035em}
.sidebar{width:212px;background:#fafbfa;padding:32px 20px;border-color:var(--border);overflow-y:auto}
.brand{font-size:23px;font-weight:650;letter-spacing:-.7px;margin:0 12px 42px}
.sidebar nav{gap:3px}.sidebar nav a{font-size:13px;font-weight:400;padding:10px 12px;border-radius:5px;color:#6a716c}
.sidebar nav a>span{display:none}.sidebar nav a.active{color:var(--ink);background:#eaf0eb;font-weight:600}
.module-nav-label{font-size:10px;font-weight:500;color:#888e89;letter-spacing:.9px;padding:25px 12px 8px}
.sidebar-bottom{padding:28px 12px 0}.sidebar-bottom strong{font-size:11px;font-weight:500;color:var(--muted)}
.side-progress{height:3px;background:var(--border);margin:13px 0 7px}.side-progress>span{background:var(--green)}
.sidebar-bottom small{color:var(--muted)}body:not(.in-module) .sidebar-bottom,body:not(.in-module) #motion-button{display:none}
.shell{margin-left:212px}.topbar{min-height:73px;padding:18px 48px;border-color:var(--border)}
#breadcrumbs{display:flex;align-items:center;flex-wrap:wrap;gap:9px;margin:0;padding:0;overflow:visible;font-size:12px;color:var(--muted)}
#breadcrumbs a{display:inline;padding:0;border-radius:0;color:var(--muted);font-size:12px;font-weight:400}
#breadcrumbs a:hover{background:none;color:var(--ink);text-decoration:underline}#breadcrumbs [aria-current]{color:var(--ink)}
.breadcrumb-separator{color:#b6bcb7}.header-actions{gap:14px}.search-button{font-size:12px;gap:9px;color:var(--muted)}
.search-button kbd{background:#fafbfa}.icon-button{border-radius:5px;font-size:17px}
main{max-width:1120px;padding:46px 48px 64px;min-height:calc(100vh - 133px)}
body:not(.in-module) main{max-width:980px;margin-left:0}
.page-enter{animation:none}.page-intro{margin:0 0 36px}.page-intro h1,.lesson-title h1{font-size:30px;font-weight:600;line-height:1.25}
.page-intro p{font-size:14px;margin-top:9px}.page-intro>.eyebrow{display:none}
.library-section{margin:32px 0 0}.library-section>h2,.section-head h2{font-size:12px;font-weight:500;letter-spacing:0;color:var(--muted);margin-bottom:12px}
.catalog-list{border-top:1px solid var(--border)}
.catalog-row{display:flex;align-items:center;gap:22px;padding:21px 4px;border-bottom:1px solid var(--border);transition:background .15s}
.catalog-row:hover{background:#f8faf8}.catalog-row>div{flex:1;min-width:0}.catalog-row h3{font-size:16px;font-weight:550;letter-spacing:-.3px}
.catalog-row p{font-size:12px;margin-top:5px}.row-meta{font-size:12px;color:var(--muted);white-space:nowrap}.row-arrow{color:#929a94;font-size:17px;font-weight:400}
.module-heading{display:flex;align-items:center;justify-content:space-between;gap:22px;margin-bottom:34px}.module-heading .page-intro{margin:0}
.btn{font-weight:500;padding:10px 15px;font-size:12px;gap:12px;border-radius:5px;transition:background .15s}
.btn:hover{transform:none}.btn.secondary{border-color:#d9dfda;color:var(--ink)}.btn.secondary:hover{background:var(--soft)}
.btn.light{background:var(--soft);border-color:var(--border)}.text-button{font-weight:500}
.section-head{margin:0 0 12px;align-items:center}.section-head h2{margin:0}.section-head .counter{letter-spacing:0}
.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:0 28px;border-top:1px solid var(--border)}
.topic-card{display:flex;align-items:center;gap:16px;border:0;border-bottom:1px solid var(--border);border-radius:0;min-height:94px;padding:20px 2px;background:white;transition:background .15s;overflow:visible}
.topic-card:hover{transform:none;box-shadow:none;border-color:var(--border);background:#f8faf8}.topic-card.done{background:#fff}.topic-card.done .topic-number{color:var(--green)}
.topic-number{font-size:11px;color:#929a94;letter-spacing:0;min-width:20px}.topic-card>div{flex:1;min-width:0}
.topic-card h3{font-size:14px;font-weight:550;letter-spacing:-.3px;margin-bottom:5px}.topic-card p{font-size:11px;padding:0;max-width:none}
.study-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0 28px;border-top:1px solid var(--border)}
.study-links a{display:flex;justify-content:space-between;align-items:center;gap:10px;font-size:13px;padding:15px 2px;border-bottom:1px solid var(--border)}
.study-links a:hover{color:var(--green)}.study-links span{font-size:11px;color:var(--muted)}
.lesson-tabs{gap:6px;margin-bottom:28px}.chip{border-radius:5px;background:var(--soft);color:#646e66;font-size:11px}
.chip:hover{background:#e9eeea}.chip.active{background:#e8efea;color:var(--dark);border-color:#cfdcd2}
.lesson-head{margin:22px 0 26px}.lesson-title .eyebrow{font-size:10px;letter-spacing:1px;color:var(--muted)}
.lesson-title p{font-size:14px;line-height:1.75}.tiny-pill{background:var(--soft);color:var(--muted);font-weight:500;border-radius:4px}.tiny-pill:before{display:none}
.essential{background:#f3f6f3;border-radius:6px;padding:23px}.mini-label{font-size:10px;font-weight:600;letter-spacing:.6px;color:#66736a}
.essential li:before{color:#7c8b80}.detail-stack details,.terms-panel,.exam-item,.quick-pair{border-radius:6px}
.detail-content{color:#59675e;font-size:13px}.term{border-color:var(--border)}.term strong{font-size:13px}.term p{font-size:12px}
.terms-panel h3{font-size:17px}.takeaway{background:#f6f8f6;border-color:#a3b8a9}.lesson-source{color:var(--muted)}
.quiz-setup,.quiz-card,.result-panel{border-radius:6px;padding:28px}.quiz-setup .big-icon{display:none}
.quiz-setup h2,.quiz-card h2,.result-panel h2{font-size:24px;font-weight:550}.option{background:#fafbfa;border-radius:5px}.option>span{border-color:#d8dfd9;color:#77827a}
.option:not(:disabled):hover{background:#f0f5f0}.option.correct{background:#edf5eb}.option.wrong{background:#fcf0e8}
.feedback,.model-answer{border-radius:5px;background:#f1f6f0}.score{font-family:inherit;font-size:64px;font-weight:550}
.flash-face{border-color:var(--border);border-radius:6px;box-shadow:none}.flash-face.back{background:#f3f7f2}
.flash-face h2{font-size:25px;font-weight:550}.flash-face .topic-tag{color:var(--muted);letter-spacing:1px}.flash-face small,.card-footer{color:var(--muted)}
.study-progress{height:3px;background:var(--border)}.study-progress span{background:#87a28c}
.lab{border-radius:6px}.lab-visual{background:#f8faf7}.lab-content h2{font-size:24px;font-weight:550}
.lab-note{border-radius:5px;background:#f2f6f1}.flow-node{border-radius:6px}.exam-inner textarea{background:#fafbfa}
.quick-pair{line-height:1.7}.quick-pair strong{font-weight:600}.exam-item summary .q-number{color:var(--muted)}
footer{max-width:1120px;padding:18px 48px;font-size:10px;min-height:60px;color:#858d87;border-color:var(--border)}
footer .text-button{color:var(--muted)}.save-note{margin-left:auto}body:not(.in-module) footer{border:0}
dialog{border-radius:8px;background:white;box-shadow:0 12px 80px #1d2b2320}dialog::backdrop{background:#222b2540;backdrop-filter:blur(2px)}
.dialog-head h2{font-size:22px}#toast{left:calc(50% + 106px);border-radius:5px;box-shadow:none}
@media(max-width:1100px){.topbar,main,footer{padding-left:30px;padding-right:30px}.learn-grid{grid-template-columns:1.4fr 1fr}}
@media(max-width:800px){
 .sidebar{position:static;width:100%;padding:22px 22px 0;border-right:0;border-bottom:1px solid var(--border)}
 .brand{font-size:21px;margin:0 0 18px}.sidebar nav{display:flex;gap:3px;margin:0 -9px;padding:0 0 13px;overflow-x:auto}
 .sidebar nav a{font-size:12px;padding:8px 9px;white-space:nowrap;flex-shrink:0}.module-nav-label{display:none}
 .sidebar-bottom{display:none}.shell{margin-left:0}.topbar{padding:14px 22px;gap:16px;min-height:56px;align-items:flex-start}
 #breadcrumbs{font-size:11px;gap:7px;line-height:1.9}#breadcrumbs a{font-size:11px}.header-actions{gap:9px;flex-shrink:0}
 .search-text,.search-button kbd{display:none}.search-button{min-width:28px;min-height:28px;justify-content:center}
 main{padding:32px 22px 48px;min-height:calc(100vh - 237px)}body:not(.in-module) main{margin:0}
 .page-intro h1,.lesson-title h1{font-size:28px}.page-intro{margin-bottom:30px}.catalog-row{padding:20px 2px;gap:14px}
 .learn-grid{grid-template-columns:1fr}.topic-grid{gap:0 22px}.module-heading{margin-bottom:30px}
 footer{padding:18px 22px}.save-note,footer .save-note{margin-left:auto;width:auto}#toast{left:50%}
}
@media(max-width:540px){
 .topic-grid,.study-links{grid-template-columns:1fr}.topic-card{min-height:85px;padding:18px 2px}
 .module-heading{align-items:flex-start;flex-direction:column;gap:18px}.module-heading .btn{padding:9px 13px}
 .catalog-row h3{font-size:15px}.catalog-row p{font-size:12px}.row-meta{font-size:11px}.library-section{margin-top:29px}
 .page-intro h1,.lesson-title h1{font-size:27px}.page-intro p{font-size:13px}.quiz-setup,.quiz-card,.result-panel{padding:22px 18px}
 .quiz-card h2{font-size:22px}.quiz-setup h2{font-size:21px}.flash-face h2{font-size:23px}.terms-panel{display:block}
 .exam-item summary{font-size:13px}.lesson-head{gap:12px}.lab-content h2{font-size:23px}.quick-grid{grid-template-columns:1fr}
}