:root{--bg:#f2f5f9;--surface:#fff;--surface2:#f7f9fc;--text:#12213a;--muted:#66758a;--line:#dbe3ee;--brand:#2859d6;--brand2:#6a42d8;--good:#16825d;--warn:#b86b00;--bad:#c43d4b;--shadow:0 16px 40px rgba(28,47,79,.09);--radius:20px}
[data-theme=dark]{--bg:#0e1624;--surface:#152135;--surface2:#101b2c;--text:#ecf3ff;--muted:#a9b8cd;--line:#2b3a50;--brand:#7ea5ff;--brand2:#b59bff;--good:#63d6a8;--warn:#ffc266;--bad:#ff8794;--shadow:0 16px 44px rgba(0,0,0,.3)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--text);font:16px/1.55 Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif}.skip{position:fixed;left:-999px;top:8px;z-index:99;background:var(--text);color:var(--surface);padding:10px}.skip:focus{left:8px}.app-shell{min-height:100vh;display:grid;grid-template-columns:260px 1fr}.sidebar{position:sticky;top:0;height:100vh;padding:22px 16px;border-right:1px solid var(--line);background:var(--surface);display:flex;flex-direction:column;z-index:20}.brand{display:flex;gap:12px;align-items:center;color:var(--text);text-decoration:none;padding:4px 8px 22px}.brand-mark{width:42px;height:42px;border-radius:14px;display:grid;place-items:center;background:linear-gradient(145deg,var(--brand),var(--brand2));color:white;font-weight:900;font-size:1.25rem}.brand small{display:block;color:var(--muted)}nav{display:grid;gap:5px}.nav-link{display:flex;gap:12px;align-items:center;padding:11px 13px;border-radius:13px;color:var(--muted);text-decoration:none;font-weight:720}.nav-link:hover,.nav-link.active{background:var(--surface2);color:var(--brand)}.side-note{margin-top:auto;padding:16px;border-radius:16px;background:linear-gradient(145deg,var(--brand),var(--brand2));color:white}.side-note span{display:block;font-size:.86rem;opacity:.85}.app-main{min-width:0}.topbar{height:74px;position:sticky;top:0;z-index:15;display:flex;align-items:center;gap:14px;padding:0 28px;border-bottom:1px solid var(--line);background:color-mix(in srgb,var(--surface) 92%,transparent);backdrop-filter:blur(14px)}.topbar small{display:block;color:var(--muted)}.top-actions{margin-left:auto;display:flex;gap:9px;align-items:center}.icon-btn{border:1px solid var(--line);background:var(--surface);color:var(--text);width:42px;height:42px;border-radius:13px;cursor:pointer;font-size:1.1rem}.icon-btn:hover{border-color:var(--brand)}#menuBtn{display:none}main{max-width:1350px;margin:auto;padding:30px}.hero{background:linear-gradient(125deg,#12213a,#274d93 58%,#6a42d8);color:white;border-radius:28px;padding:30px;display:grid;grid-template-columns:1.5fr 1fr;gap:28px;box-shadow:var(--shadow)}.hero h1{font-size:clamp(1.8rem,3.6vw,3rem);line-height:1.05;margin:0 0 12px}.hero p{max-width:700px;color:#dbe7ff}.hero-actions,.actions{display:flex;gap:10px;flex-wrap:wrap}.hero-metrics{display:grid;grid-template-columns:1fr 1fr;gap:10px}.hero-metric{padding:16px;background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.17);border-radius:18px}.hero-metric strong{font-size:1.5rem;display:block}.btn{border:1px solid transparent;border-radius:13px;padding:11px 16px;font:inherit;font-weight:800;cursor:pointer;background:var(--brand);color:white;text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:8px}.btn:hover{filter:brightness(1.07);transform:translateY(-1px)}.btn.secondary{background:var(--surface);border-color:var(--line);color:var(--text)}.btn.ghost{background:transparent;border-color:currentColor;color:inherit}.btn.good{background:var(--good)}.btn.warn{background:var(--warn)}.section-head{display:flex;justify-content:space-between;gap:14px;align-items:end;margin:30px 0 14px}.section-head h2,.section-head h1{margin:0}.section-head p{margin:4px 0 0;color:var(--muted)}.grid{display:grid;gap:16px}.grid.cols-4{grid-template-columns:repeat(4,minmax(0,1fr))}.grid.cols-3{grid-template-columns:repeat(3,minmax(0,1fr))}.grid.cols-2{grid-template-columns:repeat(2,minmax(0,1fr))}.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow)}.card h3{margin:0 0 8px}.muted{color:var(--muted)}.stat strong{display:block;font-size:1.75rem}.progress{height:9px;border-radius:999px;background:var(--surface2);overflow:hidden;border:1px solid var(--line)}.progress>i{display:block;height:100%;background:linear-gradient(90deg,var(--brand),var(--brand2));border-radius:inherit}.topic-card{display:flex;flex-direction:column;gap:12px}.topic-head{display:flex;justify-content:space-between;gap:10px}.topic-icon{width:42px;height:42px;border-radius:13px;display:grid;place-items:center;background:var(--surface2);color:var(--brand);font-weight:900}.topic-card .btn{margin-top:auto}.badge,.pill{display:inline-flex;align-items:center;border:1px solid var(--line);background:var(--surface2);color:var(--muted);border-radius:999px;padding:5px 10px;font-size:.84rem;font-weight:750}.badge.good{color:var(--good)}.badge.warn{color:var(--warn)}.badge.bad{color:var(--bad)}.coach{border-left:5px solid var(--brand)}.module-hero{display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:18px}.module-hero .topic-icon{width:64px;height:64px;font-size:1.4rem}.tabs{display:flex;gap:8px;flex-wrap:wrap;margin:18px 0}.tab{border:1px solid var(--line);background:var(--surface);color:var(--muted);padding:9px 13px;border-radius:12px;cursor:pointer;font-weight:750}.tab.active{background:var(--brand);color:white;border-color:var(--brand)}.explanation-list{display:grid;gap:12px}.explanation-list>div{padding:14px;border-radius:14px;background:var(--surface2);border:1px solid var(--line)}.operator-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}.operator{padding:14px;border:1px solid var(--line);border-radius:15px;background:var(--surface2)}.operator b{display:block;color:var(--brand);text-transform:capitalize}.quiz-shell{max-width:880px;margin:auto}.quiz-meta{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:14px}.question-card{padding:26px}.question-card h2{font-size:1.35rem}.options{display:grid;gap:10px;margin:18px 0}.option{display:flex;gap:12px;align-items:flex-start;border:1.5px solid var(--line);background:var(--surface2);border-radius:15px;padding:13px;cursor:pointer}.option:hover{border-color:var(--brand)}.option.correct{border-color:var(--good);background:color-mix(in srgb,var(--good) 10%,var(--surface))}.option.wrong{border-color:var(--bad);background:color-mix(in srgb,var(--bad) 10%,var(--surface))}.option input{margin-top:5px}.answer-input,select{width:100%;padding:12px;border:1px solid var(--line);border-radius:12px;background:var(--surface);color:var(--text);font:inherit}.solution{margin-top:18px;padding:17px;border-radius:15px;border:1px solid color-mix(in srgb,var(--brand) 35%,var(--line));background:color-mix(in srgb,var(--brand) 8%,var(--surface))}.confidence{display:flex;gap:8px;flex-wrap:wrap;margin-top:15px}.confidence button{flex:1;min-width:130px}.result-ok{color:var(--good)}.result-bad{color:var(--bad)}.formula{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;padding:13px;border-radius:13px;background:var(--surface2);border:1px solid var(--line);overflow:auto}.exam-header{position:sticky;top:88px;z-index:8;display:flex;justify-content:space-between;align-items:center}.timer{font-variant-numeric:tabular-nums;font-size:1.25rem;font-weight:900}.exam-nav{display:flex;gap:6px;flex-wrap:wrap}.exam-nav button{width:34px;height:34px;border-radius:10px;border:1px solid var(--line);background:var(--surface);color:var(--text)}.exam-nav button.active{background:var(--brand);color:#fff}.error-item{border-left:4px solid var(--bad)}.empty{text-align:center;padding:42px;color:var(--muted)}.settings-row{display:flex;justify-content:space-between;gap:20px;align-items:center;padding:14px 0;border-bottom:1px solid var(--line)}.settings-row:last-child{border:0}.search{max-width:420px}.callout{padding:15px;border-radius:15px;background:color-mix(in srgb,var(--warn) 10%,var(--surface));border:1px solid color-mix(in srgb,var(--warn) 40%,var(--line))}#toast{position:fixed;right:20px;bottom:20px;z-index:100;background:var(--text);color:var(--surface);padding:12px 16px;border-radius:13px;opacity:0;transform:translateY(15px);transition:.2s;pointer-events:none}#toast.show{opacity:1;transform:none}
@media(max-width:1050px){.grid.cols-4{grid-template-columns:repeat(2,1fr)}.grid.cols-3{grid-template-columns:repeat(2,1fr)}.hero{grid-template-columns:1fr}.operator-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:760px){.app-shell{grid-template-columns:1fr}.sidebar{position:fixed;transform:translateX(-105%);transition:.2s;width:270px;box-shadow:var(--shadow)}body.menu-open .sidebar{transform:none}#menuBtn{display:block}.topbar{padding:0 14px}main{padding:18px}.grid.cols-4,.grid.cols-3,.grid.cols-2{grid-template-columns:1fr}.hero{padding:22px}.module-hero{grid-template-columns:auto 1fr}.module-hero>.btn{grid-column:1/3}.operator-grid{grid-template-columns:1fr}.pill{display:none}.exam-header{top:80px;align-items:flex-start;flex-direction:column}.settings-row{align-items:flex-start;flex-direction:column}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}

/* Diagnostic onboarding and advanced question controls */
.diagnostic-hero{display:grid;grid-template-columns:1.2fr .8fr;gap:24px;align-items:center;padding:30px;background:linear-gradient(135deg,color-mix(in srgb,var(--brand) 10%,var(--surface)),var(--surface))}.diagnostic-hero h1{font-size:clamp(2rem,4vw,3.2rem);line-height:1.05;margin:10px 0}.diagnostic-facts{display:flex;gap:8px;flex-wrap:wrap;margin:18px 0}.diagnostic-facts span{padding:7px 11px;border-radius:999px;background:var(--surface2);border:1px solid var(--line);font-weight:750;color:var(--muted)}.diagnostic-map{display:grid;grid-template-columns:repeat(4,1fr);gap:8px}.diagnostic-map>div{min-height:82px;padding:10px;border:1px solid var(--line);border-radius:15px;background:var(--surface);display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center}.diagnostic-map span{font-size:1.35rem;color:var(--brand);font-weight:900}.diagnostic-map small{font-size:.72rem;line-height:1.15;color:var(--muted)}.multi-input-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin:18px 0}.multi-input-grid label{display:grid;gap:6px;font-weight:750}.multi-input-grid label span{font-size:.9rem;color:var(--muted)}.question-card h2{white-space:pre-line}.exam-nav button.answered:not(.active){border-color:var(--good);box-shadow:inset 0 0 0 1px var(--good)}
@media(max-width:900px){.diagnostic-hero{grid-template-columns:1fr}.diagnostic-map{grid-template-columns:repeat(4,1fr)}}
@media(max-width:600px){.diagnostic-map{grid-template-columns:repeat(2,1fr)}.multi-input-grid{grid-template-columns:1fr}}