:root{
  color-scheme:light;
  --bg:#f5f7fb;
  --surface:#ffffff;
  --surface-2:#edf2f8;
  --text:#122039;
  --muted:#61708a;
  --line:#dce4ef;
  --navy:#0a2342;
  --blue:#1769aa;
  --blue-soft:#e7f2fb;
  --red:#c92a2a;
  --red-soft:#fdecec;
  --green:#147d55;
  --green-soft:#e5f6ee;
  --amber:#9a6500;
  --amber-soft:#fff4d6;
  --shadow:0 12px 30px rgba(10,35,66,.08);
  --radius:22px;
  --radius-sm:14px;
}
[data-theme="dark"]{
  color-scheme:dark;
  --bg:#071426;
  --surface:#0d2037;
  --surface-2:#132b46;
  --text:#edf5ff;
  --muted:#a9b8cb;
  --line:#203a57;
  --navy:#dcecff;
  --blue:#66b7ee;
  --blue-soft:#123553;
  --red:#ff8a84;
  --red-soft:#3b2024;
  --green:#6cd7a8;
  --green-soft:#12352a;
  --amber:#ffd16a;
  --amber-soft:#3b301a;
  --shadow:0 12px 34px rgba(0,0,0,.25);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;line-height:1.5;padding-bottom:calc(104px + env(safe-area-inset-bottom));min-height:100vh}
button,select,input{font:inherit}
button,a{-webkit-tap-highlight-color:transparent}
button{color:inherit}
a{color:var(--blue)}
[hidden]{display:none!important}
:focus-visible{outline:3px solid var(--blue);outline-offset:3px}
.skip-link{position:fixed;left:12px;top:-80px;z-index:100;background:var(--surface);color:var(--text);padding:10px 14px;border-radius:10px;box-shadow:var(--shadow)}
.skip-link:focus{top:12px}
.app-header{position:sticky;top:0;z-index:30;background:color-mix(in srgb,var(--surface) 92%,transparent);border-bottom:1px solid var(--line);backdrop-filter:blur(18px);padding-top:env(safe-area-inset-top)}
.topbar{max-width:920px;margin:0 auto;padding:12px 16px 8px;display:flex;align-items:center;gap:12px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);min-width:0}
.brand-mark{width:46px;height:46px;flex:none;border-radius:15px;display:grid;place-items:center;background:linear-gradient(145deg,var(--navy),#1769aa);color:#fff;font-size:15px;font-weight:900;letter-spacing:.04em;box-shadow:0 8px 18px rgba(23,105,170,.24)}
.brand-copy{display:grid;line-height:1.15;min-width:0}
.brand-copy strong{font-size:17px}
.brand-copy small{font-size:12px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.header-actions{margin-left:auto;display:flex;align-items:center;gap:7px}
.network-pill{font-size:11px;color:var(--green);background:var(--green-soft);padding:6px 8px;border-radius:999px;font-weight:800}
.network-pill.offline{color:var(--amber);background:var(--amber-soft)}
.pill-button,.icon-button{border:1px solid var(--line);background:var(--surface);color:var(--text);min-height:40px;border-radius:999px;padding:8px 11px;font-weight:800;cursor:pointer}
.icon-button{min-width:42px}
.progress-header{max-width:920px;margin:0 auto;padding:0 16px 11px}
.level-line{display:flex;justify-content:space-between;gap:10px;color:var(--muted);font-size:11.5px;font-weight:700;margin-bottom:5px}
.progress-track{height:9px;background:var(--surface-2);border-radius:999px;overflow:hidden}
.progress-track>span{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--blue),#50a7e6);border-radius:inherit;transition:width .25s ease}
.progress-track.light{height:7px;background:var(--blue-soft)}
.update-banner{max-width:920px;margin:10px auto 0;padding:10px 12px;background:var(--amber-soft);color:var(--amber);border:1px solid color-mix(in srgb,var(--amber) 30%,transparent);border-radius:14px;display:flex;align-items:center;justify-content:space-between;gap:12px;font-size:13px;font-weight:700}
main{max-width:920px;margin:0 auto;padding:20px 16px 36px;outline:none}
.view{display:none}
.view.active{display:block;animation:view-in .22s ease}
.page-heading,.section-heading{display:flex;align-items:center;justify-content:space-between;gap:14px;margin-bottom:16px}
.page-heading h1,.section-heading h2{margin:0;font-size:clamp(25px,5vw,36px);line-height:1.1;letter-spacing:-.03em}
.section-heading h2{font-size:24px}
.eyebrow{display:block;color:var(--blue);font-size:11.5px;text-transform:uppercase;letter-spacing:.11em;font-weight:900;margin-bottom:4px}
.hero{position:relative;overflow:hidden;background:linear-gradient(145deg,#0a2342 0%,#104b78 62%,#1769aa 100%);color:#fff;border-radius:28px;padding:clamp(24px,6vw,48px);box-shadow:0 20px 45px rgba(10,35,66,.2);margin-bottom:16px}
.hero:after{content:"CL";position:absolute;right:-12px;bottom:-60px;font-size:210px;line-height:1;font-weight:900;color:rgba(255,255,255,.06);pointer-events:none}
.hero .eyebrow{color:#a9dcff}
.hero h1{font-size:clamp(32px,7vw,54px);max-width:680px;line-height:1.02;letter-spacing:-.045em;margin:8px 0 14px}
.hero p{color:#d6eaff;max-width:670px;font-size:16px;margin:0 0 18px}
.hero>small{display:block;color:#bcd9ef;font-size:12px;margin-top:12px;max-width:700px}
.format-card{position:relative;z-index:1;display:flex;flex-wrap:wrap;align-items:center;gap:8px 16px;background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.18);border-radius:16px;padding:12px 14px;margin-bottom:18px}
.format-card .format-title{font-size:15px}
.format-card .format-note{font-size:12px;color:inherit;opacity:.82}
.button-row{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.button{border:1px solid transparent;border-radius:14px;min-height:48px;padding:11px 15px;display:inline-flex;align-items:center;justify-content:center;gap:8px;text-decoration:none;font-weight:850;cursor:pointer;transition:transform .15s ease,filter .15s ease,border-color .15s ease}
.button:hover{filter:brightness(.98);transform:translateY(-1px)}
.button:active{transform:translateY(0)}
.button:disabled{cursor:not-allowed;opacity:.5;transform:none}
.button-primary{background:#c92a2a;color:#fff}
.button-dark{background:var(--navy);color:var(--bg)}
.button-light{background:#fff;color:#0a2342}
.button-ghost{background:var(--surface);color:var(--text);border-color:var(--line)}
.button-small{min-height:40px;padding:8px 12px;border-radius:11px;font-size:13px}
.text-button{border:0;background:none;color:var(--blue);font-weight:850;cursor:pointer;padding:8px}
.feature-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-bottom:16px}
.feature-card{text-align:left;background:var(--surface);border:1px solid var(--line);border-radius:18px;padding:16px;min-height:150px;cursor:pointer;display:flex;flex-direction:column;gap:5px;box-shadow:0 4px 18px rgba(10,35,66,.04)}
.feature-card:hover{border-color:var(--blue);transform:translateY(-2px)}
.feature-label{font-size:11px;text-transform:uppercase;letter-spacing:.1em;color:var(--blue);font-weight:900}
.feature-card strong{font-size:17px;line-height:1.2}
.feature-card>span:last-child{color:var(--muted);font-size:13px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:clamp(16px,3vw,24px);box-shadow:var(--shadow);margin-bottom:16px}
.card h2{font-size:24px;line-height:1.15;margin:0 0 9px;letter-spacing:-.025em}
.card h3{font-size:17px;margin:18px 0 6px}
.card p,.class-section p{color:var(--muted);margin:0 0 12px}
.study-steps{list-style:none;padding:0;margin:18px 0}
.study-steps li{display:flex;align-items:center;gap:12px;padding:10px 0;border-bottom:1px solid var(--line)}
.study-steps li>span{width:34px;height:34px;border-radius:11px;display:grid;place-items:center;background:var(--blue-soft);color:var(--blue);font-weight:900;flex:none}
.study-steps div{display:grid}
.study-steps small{color:var(--muted)}
.select-label{display:block;font-size:12px;font-weight:850;margin:12px 0 6px}
select{width:100%;min-height:48px;border:1px solid var(--line);border-radius:13px;background:var(--surface);color:var(--text);padding:9px 12px;margin-bottom:12px}
.metric-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:9px;margin:12px 0 18px}
.metric{background:var(--surface-2);border-radius:14px;padding:12px;display:grid;gap:1px}
.metric strong{font-size:22px;line-height:1.1}
.metric span{font-size:11.5px;color:var(--muted)}
.mastery-line{display:flex;justify-content:space-between;gap:12px;font-size:13px;margin:12px 0 7px}
.mastery-line span{color:var(--muted)}
.trust-card{border-left:4px solid var(--blue);background:var(--blue-soft);border-radius:0 16px 16px 0;padding:16px 18px;margin-bottom:12px}
.trust-card p{color:var(--muted);font-size:13px;margin:5px 0 8px}
.class-tabs{display:flex;gap:8px;overflow-x:auto;padding:2px 1px 12px;scrollbar-width:thin}
.class-tab{min-width:58px;min-height:48px;border:1px solid var(--line);background:var(--surface);border-radius:14px;font-weight:900;cursor:pointer}
.class-tab.active{background:var(--navy);border-color:var(--navy);color:var(--bg)}
.class-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:clamp(18px,4vw,30px);box-shadow:var(--shadow)}
.class-heading{display:flex;gap:16px;align-items:center;margin-bottom:20px}
.class-code{width:64px;height:64px;border-radius:18px;background:var(--navy);color:var(--bg);display:grid;place-items:center;font-size:19px;font-weight:900;flex:none}
.class-heading h2{margin:0;font-size:clamp(23px,5vw,34px)}
.class-kicker{color:var(--muted);margin:4px 0 0}
.class-section{padding:16px 0;border-top:1px solid var(--line)}
.class-section h3{margin:0 0 7px}
.requirement-list{margin:0;padding-left:20px}
.requirement-list li{margin:7px 0;color:var(--muted)}
.class-format{display:flex;background:var(--blue-soft);color:var(--blue);border:0;margin:18px 0}
.tip-box{background:var(--amber-soft);color:var(--amber);padding:14px;border-radius:14px;margin:16px 0}
.tip-box p{color:inherit;margin:4px 0 0;font-size:14px}
.exam-start{text-align:center;padding:34px 22px}
.exam-start .format-card{background:var(--blue-soft);color:var(--blue);justify-content:center;margin:18px auto;max-width:620px}
.exam-toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:12px 14px;margin-bottom:10px}
.exam-toolbar>div:first-child{display:flex;align-items:center;gap:8px;color:var(--muted);font-size:13px}
.status-chip,.points-chip{display:inline-flex;align-items:center;background:var(--blue-soft);color:var(--blue);border-radius:999px;padding:5px 9px;font-size:11.5px;font-weight:900}
.timer{font-variant-numeric:tabular-nums;font-weight:900;background:var(--navy);color:var(--bg);border-radius:11px;padding:8px 11px;min-width:88px;text-align:center}
.timer.warning{background:var(--red);color:#fff}
.question-progress{display:grid;grid-template-columns:1fr auto;align-items:center;gap:12px;margin:12px 0}
.question-progress>span{font-size:12px;color:var(--muted);white-space:nowrap}
.question-nav{display:grid;grid-template-columns:repeat(5,1fr);gap:7px;margin:12px 0}
.question-nav button{min-height:44px;border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:11px;font-weight:850;cursor:pointer}
.question-nav button.answered{background:var(--blue-soft);border-color:var(--blue);color:var(--blue)}
.question-nav button.current{outline:3px solid var(--navy);outline-offset:1px}
.question-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:clamp(18px,4vw,30px);box-shadow:var(--shadow)}
.question-meta{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:13px}
.question-topic{font-size:12px;font-weight:850;color:var(--muted);text-transform:uppercase;letter-spacing:.08em}
.question-card h2,.card>#practice-question{font-size:clamp(20px,4vw,28px);line-height:1.3;margin:0 0 20px;letter-spacing:-.02em}
.options{display:grid;gap:10px}
.option{width:100%;min-height:58px;border:2px solid var(--line);background:var(--surface);color:var(--text);border-radius:15px;padding:11px 13px;display:grid;grid-template-columns:34px 1fr;align-items:center;gap:10px;text-align:left;cursor:pointer;font-weight:650}
.option:hover:not(:disabled){border-color:var(--blue);background:var(--blue-soft)}
.option:disabled{cursor:default;opacity:1}
.option.selected{border-color:var(--blue);background:var(--blue-soft)}
.option.correct{border-color:var(--green);background:var(--green-soft)}
.option.incorrect{border-color:var(--red);background:var(--red-soft)}
.option-letter{width:32px;height:32px;border-radius:10px;background:var(--surface-2);display:grid;place-items:center;font-weight:900}
.sticky-actions{position:sticky;bottom:calc(78px + env(safe-area-inset-bottom));z-index:5;background:color-mix(in srgb,var(--bg) 88%,transparent);padding:8px 0;backdrop-filter:blur(10px);margin-top:12px}
.finish-button{margin-top:8px}
.result-card{margin-top:16px;border-top:5px solid var(--blue)}
.result-title{font-size:clamp(26px,6vw,38px)!important}
.score-line{display:flex;align-items:baseline;gap:12px;margin:16px 0}
.score-line strong{font-size:48px;line-height:1;color:var(--blue)}
.score-line span{font-size:19px;color:var(--muted);font-weight:850}
.result-metrics{display:grid;grid-template-columns:repeat(3,1fr);gap:9px;margin:18px 0}
.warning-text{background:var(--red-soft);color:var(--red);padding:12px;border-radius:12px}
.result-note{font-size:13px;color:var(--muted)}
.review-title{margin-top:26px!important}
.review-item{border:1px solid var(--line);border-radius:13px;padding:0;margin:8px 0;background:var(--surface)}
.review-item summary{cursor:pointer;padding:12px;display:grid;grid-template-columns:72px 1fr;gap:8px;font-size:13px;font-weight:750}
.review-status{color:var(--green);font-weight:900}
.review-item:has(.incorrect) .review-status{color:var(--red)}
.review-body{padding:0 12px 12px;font-size:13px}
.review-body p{margin:5px 0}
.correct-answer{color:var(--green);font-weight:750}
.explanation{background:var(--amber-soft);color:var(--amber);padding:10px;border-radius:10px}
.feedback{margin-top:14px;border-radius:14px;padding:14px}
.feedback.correct{background:var(--green-soft);color:var(--green)}
.feedback.incorrect{background:var(--red-soft);color:var(--red)}
.feedback p{margin:5px 0 0}
.practice-next{margin-top:14px}
.practice-complete{background:var(--blue-soft);color:var(--blue);border-radius:15px;padding:22px;text-align:center}
.practice-complete strong{font-size:30px;display:block}
.practice-complete p{margin:5px 0 0}
.filter-row{display:flex;gap:8px;overflow-x:auto;padding-bottom:12px}
.filter-chip{min-height:42px;white-space:nowrap;border:1px solid var(--line);background:var(--surface);border-radius:999px;padding:8px 13px;font-weight:800;cursor:pointer}
.filter-chip.active{background:var(--navy);border-color:var(--navy);color:var(--bg)}
.signal-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin-top:18px}
.signal-card{background:var(--surface);border:1px solid var(--line);border-radius:18px;padding:16px;display:flex;flex-direction:column;min-height:240px;box-shadow:0 4px 18px rgba(10,35,66,.04)}
.signal-top{display:flex;justify-content:space-between;gap:8px;align-items:center}
.signal-code{background:var(--navy);color:var(--bg);border-radius:9px;padding:6px 8px;font-size:12px;font-weight:900}
.signal-type{font-size:11px;color:var(--muted);font-weight:800}
.signal-card h2{font-size:20px;line-height:1.2;margin:18px 0 10px}
.signal-description{background:var(--blue-soft);color:var(--blue);padding:12px;border-radius:12px;font-size:13px;margin:0 0 12px}
.known-button{margin-top:auto;min-height:44px;border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:12px;font-weight:850;cursor:pointer}
.known-button.known{background:var(--green-soft);border-color:var(--green);color:var(--green)}
.checklist{display:grid;gap:9px;margin:16px 0}
.check-item{display:grid;grid-template-columns:26px 1fr;gap:10px;align-items:start;background:var(--surface-2);border-radius:14px;padding:12px;cursor:pointer}
.check-item input{width:22px;height:22px;accent-color:var(--blue)}
.check-item>span{display:grid}
.check-item small{color:var(--muted)}
.info-card{border-left:5px solid var(--blue)}
.source-card{display:grid;gap:10px}
.source-card a{padding:12px;background:var(--blue-soft);border-radius:12px;text-decoration:none;font-weight:800}
details{border:1px solid var(--line);border-radius:14px;padding:0;margin:10px 0;background:var(--surface)}
summary{cursor:pointer;padding:14px;font-weight:850;min-height:48px;display:flex;align-items:center}
details>ul,details>p{padding:0 16px 14px 34px;color:var(--muted)}
.topic-list{display:grid;gap:8px;margin:14px 0 18px}
.topic-row{border:1px solid var(--line);background:var(--surface);border-radius:13px;padding:12px;display:flex;justify-content:space-between;gap:12px;cursor:pointer;text-align:left}
.topic-row strong{color:var(--red)}
.empty-state{background:var(--surface-2);color:var(--muted);padding:16px;border-radius:14px}
.danger-button{margin-top:16px;border:1px solid var(--red);background:transparent;color:var(--red);border-radius:12px;min-height:44px;padding:9px 13px;font-weight:850;cursor:pointer}
.tabbar{position:fixed;left:0;right:0;bottom:0;z-index:40;background:color-mix(in srgb,var(--surface) 94%,transparent);border-top:1px solid var(--line);display:grid;grid-template-columns:repeat(5,1fr);padding:7px 8px calc(7px + env(safe-area-inset-bottom));backdrop-filter:blur(18px)}
.tabbar button{border:0;background:none;color:var(--muted);min-height:52px;border-radius:12px;font-size:11.5px;font-weight:850;cursor:pointer}
.tabbar button.active{background:var(--blue-soft);color:var(--blue)}
.install-banner{position:fixed;z-index:50;left:50%;transform:translateX(-50%);bottom:calc(82px + env(safe-area-inset-bottom));width:min(620px,calc(100% - 24px));background:var(--surface);border:1px solid var(--line);border-radius:18px;padding:12px;box-shadow:0 18px 50px rgba(0,0,0,.22);display:grid;grid-template-columns:1fr auto auto;align-items:center;gap:9px}
.install-banner>div{display:grid}
.install-banner span{font-size:12px;color:var(--muted)}
.toast{position:fixed;z-index:60;left:50%;transform:translateX(-50%);bottom:calc(88px + env(safe-area-inset-bottom));width:max-content;max-width:calc(100% - 28px);background:#10213a;color:#fff;border-radius:999px;padding:11px 16px;box-shadow:var(--shadow);font-size:13px;font-weight:750;text-align:center}
@keyframes view-in{from{opacity:0;transform:translateY(7px)}to{opacity:1;transform:none}}
@media(max-width:760px){
  .feature-grid{grid-template-columns:1fr 1fr}
  .feature-card{min-height:138px}
  .brand-copy small,.network-pill{display:none}
  .question-nav{grid-template-columns:repeat(5,1fr)}
}
@media(max-width:520px){
  .topbar{padding-inline:12px}
  .header-actions{gap:5px}
  .pill-button,.icon-button{font-size:12px;padding:7px 9px}
  main{padding:14px 12px 28px}
  .button-row{grid-template-columns:1fr}
  .hero{border-radius:22px;padding:24px 20px}
  .hero h1{font-size:36px}
  .feature-grid{grid-template-columns:1fr 1fr}
  .metric-grid{grid-template-columns:1fr 1fr}
  .signal-grid{grid-template-columns:1fr}
  .class-heading{align-items:flex-start}
  .class-code{width:54px;height:54px}
  .page-heading{align-items:flex-start}
  .exam-toolbar{align-items:flex-start}
  .result-metrics{grid-template-columns:1fr}
  .install-banner{grid-template-columns:1fr auto}
  .install-banner .icon-button{grid-column:2;grid-row:1}
  .install-banner .button{grid-column:1/3;grid-row:2}
}
@media(max-width:360px){
  .feature-grid{grid-template-columns:1fr}
  .brand-copy strong{font-size:15px}
  .icon-button{display:none}
}
@media(min-width:721px){
  .question-nav{grid-template-columns:repeat(10,1fr)}
}
@media(prefers-reduced-motion:reduce){
  *,*:before,*:after{scroll-behavior:auto!important;animation:none!important;transition:none!important}
}
@media print{
  .app-header,.tabbar,.install-banner,.toast,.button,.sticky-actions{display:none!important}
  body{background:#fff;padding:0;color:#000}
  .view{display:none!important}
  .view.active{display:block!important}
  .card,.question-card{box-shadow:none;border:1px solid #bbb}
}