:root{--study-bg:#0b1020;--study-card:#121a2b;--study-border:#263149;--study-muted:#9aa8bd;--study-accent:#76a9fa;--study-good:#34d399;--study-warn:#fbbf24;--study-bad:#fb7185}html[data-bs-theme="dark"] body{background:var(--study-bg);color:#e8eef8}.navbar,.offcanvas{background:#0e1627!important}.card{background:var(--study-card);border-color:var(--study-border)}.text-muted{color:var(--study-muted)!important}.progress{height:.65rem;background:#263149}.btn-primary{--bs-btn-bg:#3978d3;--bs-btn-border-color:#3978d3}.study-shell{min-height:100vh}.sidebar{width:270px;border-right:1px solid var(--study-border);background:#0e1627}.sidebar .nav-link{color:#b9c6d8;border-radius:.75rem;padding:.7rem .85rem}.sidebar .nav-link:hover{background:#18233a;color:#fff}.content{min-width:0}.metric{font-size:1.65rem;font-weight:700}.eyebrow{font-size:.75rem;letter-spacing:.08em;text-transform:uppercase;color:var(--study-muted)}.study-content{font-size:1.08rem;line-height:1.78}.study-content p{margin-bottom:1.1rem}.question-card.correct{border-color:var(--study-good)}.question-card.incorrect{border-color:var(--study-bad)}.soft-badge{background:#1b2942;border:1px solid #2c4166}.mindmap-node{border-left:3px solid var(--study-accent);padding:.5rem .75rem;margin:.35rem 0;background:#101a2d;border-radius:.4rem}.focus-mode .sidebar,.focus-mode .topbar{display:none!important}.focus-mode .content{width:100%!important}.timer{font-variant-numeric:tabular-nums}.table{--bs-table-bg:transparent}.form-control,.form-select{background-color:#0e1627;border-color:#33425f}.form-control:focus,.form-select:focus{background-color:#0e1627}.logo-dot{width:10px;height:10px;border-radius:50%;background:var(--study-good);display:inline-block}.tv-mode{font-size:1.15rem}@media(max-width:991.98px){.sidebar{display:none}.content{width:100%}.study-content{font-size:1.03rem}.mobile-bottom{display:flex!important}}@media(min-width:1600px){body{font-size:1.08rem}.container-fluid{max-width:1800px}.card{border-radius:1rem}.metric{font-size:2rem}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}

/* V2 adaptive learning */
.study-mark{background:rgba(118,169,250,.04)}
.mastery-low{color:var(--study-bad)}.mastery-mid{color:var(--study-warn)}.mastery-high{color:var(--study-good)}
@media(max-width:575.98px){.question-card .fs-5{font-size:1.05rem!important}.confidence-group{width:100%}.confidence-group label{flex:1}.study-content{line-height:1.72}.metric{font-size:1.45rem}}

/* V3 multi-track product layout */
.nav-svg,.section-icon{width:1.18rem;height:1.18rem;flex:0 0 auto}.menu-svg{width:1rem;height:1rem}.sidebar-nav .nav-link{display:flex;align-items:center;gap:.72rem}.sidebar-label{padding:.55rem .85rem .25rem;font-size:.68rem;letter-spacing:.12em;text-transform:uppercase;color:var(--study-muted)}.brand{color:inherit}.brand:hover{color:inherit}.logo-mark{display:grid;place-items:center;width:36px;height:36px;border-radius:12px;background:linear-gradient(135deg,#3978d3,#34d399);color:#fff;font-weight:800}.profile-avatar{display:inline-grid;place-items:center;width:34px;height:34px;border-radius:50%;background:#233453;color:#fff;font-weight:700;font-size:.8rem;border:1px solid #3a4d70}.profile-avatar-lg{width:72px;height:72px;font-size:1.25rem}.user-menu{border:0;background:transparent;color:inherit;padding:.25rem .45rem}.user-menu:hover,.user-menu:focus{background:rgba(118,169,250,.08);color:inherit}.track-card{transition:transform .15s ease,border-color .15s ease}.track-card:hover{transform:translateY(-2px);border-color:#3978d3}.milestone-item{border-left:3px solid var(--study-accent);padding-left:.75rem}.track-check{cursor:pointer;border-color:var(--study-border);background:rgba(118,169,250,.025)}.track-check:has(input:checked){border-color:#3978d3;background:rgba(57,120,211,.1)}
html[data-study-theme="dark-hc"]{--study-bg:#000;--study-card:#080808;--study-border:#4b5563;--study-muted:#c8d0dc;--study-accent:#8fc4ff}html[data-study-theme="dark-hc"] body{background:#000;color:#fff}html[data-study-theme="dark-hc"] .sidebar,html[data-study-theme="dark-hc"] .topbar,html[data-study-theme="dark-hc"] .offcanvas{background:#050505!important}html[data-study-theme="dark-hc"] .card{background:#090909;border-color:#555}html[data-study-theme="light"]{--study-bg:#f5f7fb;--study-card:#fff;--study-border:#dce3ee;--study-muted:#667085;--study-accent:#2868c7}html[data-study-theme="light"] body{background:var(--study-bg);color:#1f2937}html[data-study-theme="light"] .sidebar,html[data-study-theme="light"] .topbar,html[data-study-theme="light"] .offcanvas{background:#fff!important}html[data-study-theme="light"] .card{background:#fff;border-color:var(--study-border)}html[data-study-theme="light"] .sidebar .nav-link{color:#475467}html[data-study-theme="light"] .sidebar .nav-link:hover{background:#edf4ff;color:#1d4f91}html[data-study-theme="light"] .form-control,html[data-study-theme="light"] .form-select{background:#fff;border-color:#cfd8e6;color:#1f2937}html[data-study-theme="light"] .profile-avatar{background:#dce9fb;color:#174a8b}