:root {
  --navy: #07162f;
  --navy-2: #0c2347;
  --ink: #13213a;
  --muted: #647187;
  --paper: #f4f7fb;
  --white: #ffffff;
  --line: #dbe3ee;
  --lime: #cbff64;
  --lime-dark: #244804;
  --blue: #2e68ff;
  --orange: #ff9e64;
  --shadow: 0 24px 70px rgba(7, 22, 47, 0.13);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--paper);
  font-synthesis: none;
}

* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; background: var(--paper); }
.demo-banner { min-height: 40px; padding: 9px 24px; display: flex; align-items: center; justify-content: center; gap: 18px; background: var(--lime); color: var(--navy); font-size: .78rem; font-weight: 850; }
.demo-banner a { color: var(--navy); text-underline-offset: 3px; }
button { font: inherit; }
button:focus-visible, article:focus-visible { outline: 3px solid rgba(46, 104, 255, 0.45); outline-offset: 3px; }

.app-shell { min-height: 100vh; display: grid; grid-template-columns: 280px minmax(0, 1fr); }
.sidebar { position: sticky; top: 0; height: calc(100vh - 40px); padding: 30px 24px; background: var(--navy); color: white; display: flex; flex-direction: column; gap: 26px; overflow-y: auto; }
.brand-row { display: flex; align-items: center; gap: 12px; }
.brand-mark { width: 42px; height: 42px; border-radius: 12px; display: grid; place-items: center; background: var(--lime); color: var(--navy); font-weight: 900; font-size: 1.3rem; transform: rotate(-4deg); }
.brand-row strong, .brand-row span { display: block; }
.brand-row strong { font-size: 1.05rem; letter-spacing: -0.02em; }
.brand-row span { margin-top: 2px; color: #9eb0ca; font-size: 0.78rem; }

.progress-card { padding: 17px; border: 1px solid rgba(255,255,255,.12); background: rgba(255,255,255,.055); border-radius: 16px; }
.progress-topline { display: flex; justify-content: space-between; gap: 12px; font-size: .86rem; }
.progress-topline strong { color: var(--lime); }
.progress-track { height: 7px; margin: 12px 0; background: rgba(255,255,255,.11); border-radius: 20px; overflow: hidden; }
.progress-track span { display: block; width: 0; height: 100%; background: var(--lime); border-radius: inherit; transition: width .3s ease; }
.progress-card p { margin: 0; color: #aebbd0; font-size: .78rem; line-height: 1.45; }
.eyebrow { margin: 0 0 9px; color: var(--muted); font-size: .72rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
.sidebar .eyebrow { color: #758bab; }
.chapter-nav { display: grid; gap: 7px; }
.chapter-button { width: 100%; border: 0; border-radius: 12px; padding: 12px 13px; display: flex; align-items: center; justify-content: space-between; background: transparent; color: #b8c4d7; cursor: pointer; text-align: left; font-size: .9rem; transition: .2s ease; }
.chapter-button b { min-width: 25px; height: 25px; padding: 0 7px; display: grid; place-items: center; background: rgba(255,255,255,.08); border-radius: 8px; font-size: .72rem; }
.chapter-button:hover { background: rgba(255,255,255,.07); color: white; }
.chapter-button.active { background: var(--white); color: var(--navy); font-weight: 750; }
.chapter-button.active b { background: var(--lime); }
.chapter-button.locked { color: #8093af; }
.chapter-button.locked b { width: auto; color: var(--lime); font-size: .58rem; letter-spacing: .04em; text-transform: uppercase; }
.product-card { margin-top: auto; padding: 17px; border-radius: 16px; background: linear-gradient(145deg, rgba(203,255,100,.16), rgba(255,255,255,.06)); border: 1px solid rgba(203,255,100,.22); }
.mini-label { display: block; margin-bottom: 7px; color: var(--lime); font-size: .7rem; font-weight: 800; text-transform: uppercase; letter-spacing: .08em; }
.product-card strong { font-size: .9rem; }
.product-card p { color: #afbed1; font-size: .76rem; line-height: 1.5; }
.text-button { padding: 0; border: 0; background: transparent; color: white; text-decoration: underline; text-underline-offset: 4px; font-weight: 700; font-size: .78rem; cursor: pointer; }
.sidebar-buy { display: inline-block; color: white; font-size: .78rem; font-weight: 800; text-underline-offset: 4px; }

.main-area { padding: 34px clamp(22px, 4vw, 62px) 50px; overflow: hidden; }
.topbar { max-width: 1180px; margin: 0 auto 30px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.topbar h1 { margin: 0; color: var(--navy); font-size: clamp(1.55rem, 2.7vw, 2.25rem); letter-spacing: -.045em; }
.quiz-button { border: 0; padding: 13px 17px; border-radius: 13px; background: var(--navy); color: white; font-weight: 800; cursor: pointer; box-shadow: 0 10px 25px rgba(7,22,47,.15); }
.quiz-button span { margin-left: 7px; color: var(--lime); font-weight: 650; font-size: .75rem; }
.mobile-menu { display: none; }
.study-grid { max-width: 1180px; margin: 0 auto; display: grid; grid-template-columns: minmax(0, 1fr) 290px; gap: 26px; align-items: stretch; }
.lesson-column { min-width: 0; }
.lesson-meta { min-height: 28px; margin-bottom: 10px; display: flex; align-items: center; justify-content: space-between; color: var(--muted); font-size: .78rem; font-weight: 700; }
.dots { display: flex; gap: 6px; }
.dots button { width: 24px; height: 5px; padding: 0; border: 0; border-radius: 5px; background: #d7dfeb; cursor: pointer; transition: .2s ease; }
.dots button.active { width: 42px; background: var(--blue); }
.dots button.known { background: #81b72f; }
.dots button.practice { background: var(--orange); }

.flashcard { position: relative; min-height: 450px; padding: clamp(24px, 4vw, 46px); border: 1px solid rgba(7,22,47,.07); border-radius: 24px; background: var(--white); box-shadow: var(--shadow); overflow: hidden; }
.flashcard::after { content: ""; position: absolute; width: 210px; height: 210px; right: -86px; top: -92px; border: 44px solid rgba(46,104,255,.06); border-radius: 50%; pointer-events: none; }
.flashcard-topline { position: relative; z-index: 1; display: flex; justify-content: space-between; gap: 16px; }
.topic-pill, .status-pill { display: inline-flex; padding: 7px 10px; border-radius: 8px; font-size: .72rem; font-weight: 800; }
.topic-pill { background: #eaf0ff; color: #2855bf; }
.status-pill { background: #eff2f6; color: #6d788a; }
.status-pill.known { background: #edffd0; color: #315d03; }
.status-pill.practice { background: #fff0e8; color: #974619; }
.card-face { position: relative; z-index: 1; padding-top: clamp(45px, 7vw, 72px); }
.card-kicker { margin: 0 0 12px; color: var(--blue); font-size: .76rem; font-weight: 850; letter-spacing: .1em; text-transform: uppercase; }
.card-face h2 { max-width: 730px; margin: 0; color: var(--navy); font-size: clamp(2.2rem, 5.1vw, 4.75rem); line-height: .98; letter-spacing: -.06em; }
.prompt { max-width: 630px; margin: 25px 0 0; color: #536078; font-size: clamp(1.05rem, 1.8vw, 1.3rem); line-height: 1.6; }
.reveal-button { margin-top: 34px; padding: 13px 17px; border: 1px solid var(--line); border-radius: 12px; background: #f8faff; color: var(--navy); font-weight: 800; cursor: pointer; }
.answer { max-width: 720px; margin: 25px 0 18px; color: #3a485f; font-size: 1.08rem; line-height: 1.68; }
.formula { display: inline-flex; min-height: 38px; align-items: center; padding: 8px 12px; border-radius: 9px; background: var(--navy); color: var(--lime); font-weight: 800; font-size: .9rem; }
.formula:empty { display: none; }
.example-box { max-width: 720px; margin-top: 22px; padding: 15px 17px; border-left: 4px solid var(--lime); background: #f4fbe7; border-radius: 0 11px 11px 0; }
.example-box span { font-size: .7rem; font-weight: 850; letter-spacing: .08em; text-transform: uppercase; color: #4c740f; }
.example-box p { margin: 5px 0 0; font-size: .9rem; line-height: 1.5; }
.study-actions { margin-top: 16px; display: flex; flex-wrap: wrap; gap: 9px; }
.secondary-button, .practice-button, .understood-button { min-height: 45px; padding: 11px 15px; border-radius: 12px; font-weight: 800; cursor: pointer; }
.secondary-button { border: 1px solid var(--line); background: white; color: var(--navy); }
.practice-button { margin-left: auto; border: 1px solid #ffd7c0; background: #fff5ef; color: #9a471c; }
.understood-button { border: 0; background: var(--lime); color: var(--lime-dark); }

.session-panel { min-height: 478px; padding: 28px 24px; border-radius: 24px; background: var(--navy); color: white; box-shadow: var(--shadow); }
.timer-ring { width: 104px; height: 104px; margin-bottom: 26px; display: flex; flex-direction: column; align-items: center; justify-content: center; border: 9px solid rgba(255,255,255,.1); border-top-color: var(--lime); border-right-color: var(--lime); border-radius: 50%; transform: rotate(10deg); }
.timer-ring span, .timer-ring small { transform: rotate(-10deg); }
.timer-ring span { font-size: 2rem; font-weight: 900; line-height: 1; }
.timer-ring small { margin-top: 4px; color: #9eb0c9; font-size: .66rem; }
.session-panel h2 { margin: 0; font-size: 1.25rem; }
.session-panel > p { color: #aebcd0; line-height: 1.55; font-size: .86rem; }
.session-stats { margin: 24px 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 7px; }
.session-stats div { padding: 11px 6px; text-align: center; border-radius: 11px; background: rgba(255,255,255,.06); }
.session-stats dt { color: #9caec6; font-size: .62rem; }
.session-stats dd { margin: 5px 0 0; font-size: 1.05rem; font-weight: 900; }
.tip { padding: 15px; border-radius: 13px; background: rgba(203,255,100,.11); border: 1px solid rgba(203,255,100,.17); }
.tip span { color: var(--lime); font-size: .68rem; font-weight: 850; text-transform: uppercase; letter-spacing: .08em; }
.tip p { margin: 7px 0 0; color: #dce7cd; font-size: .78rem; line-height: 1.5; }
.value-strip { max-width: 1180px; margin: 35px auto 0; padding-top: 28px; display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); }
.value-strip div { padding: 0 24px; border-right: 1px solid var(--line); }
.value-strip div:first-child { padding-left: 0; }
.value-strip div:last-child { border: 0; }
.value-strip span { color: var(--blue); font-size: .7rem; font-weight: 850; }
.value-strip strong { display: block; margin-top: 7px; color: var(--navy); }
.value-strip p { margin: 5px 0 0; color: var(--muted); font-size: .82rem; }
.sales-section { max-width: 1180px; margin: 70px auto 0; padding: clamp(30px, 5vw, 56px); display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(270px, .65fr); gap: clamp(32px, 6vw, 80px); align-items: center; border-radius: 28px; background: var(--navy); color: white; overflow: hidden; }
.sales-copy h2 { max-width: 720px; margin: 0; font-size: clamp(2.1rem, 4vw, 4.2rem); line-height: 1; letter-spacing: -.055em; }
.sales-copy > p:not(.eyebrow) { max-width: 690px; color: #b8c6da; font-size: 1rem; line-height: 1.65; }
.sales-copy .eyebrow { color: var(--lime); }
.sales-copy ul { margin: 24px 0 0; padding: 0; display: grid; gap: 10px; list-style: none; }
.sales-copy li { position: relative; padding-left: 25px; color: #e1e8f3; }
.sales-copy li::before { content: "✓"; position: absolute; left: 0; color: var(--lime); font-weight: 900; }
.checkout-card { padding: 27px; border-radius: 20px; background: white; color: var(--navy); box-shadow: 0 24px 65px rgba(0,0,0,.22); }
.offer-badge { display: inline-flex; padding: 7px 9px; border-radius: 8px; background: #eaf0ff; color: #2855bf; font-size: .68rem; font-weight: 850; text-transform: uppercase; letter-spacing: .06em; }
.price { margin: 22px 0 12px; }
.price strong, .price span { display: block; }
.price strong { font-size: 2.8rem; letter-spacing: -.055em; }
.price span { margin-top: 3px; color: var(--muted); font-size: .78rem; }
.checkout-card p { color: var(--muted); font-size: .88rem; line-height: 1.5; }
.checkout-button { margin-top: 20px; min-height: 50px; padding: 13px 18px; display: flex; align-items: center; justify-content: center; border-radius: 12px; background: var(--lime); color: var(--lime-dark); font-weight: 900; text-decoration: none; }
.checkout-card small { display: block; margin-top: 12px; color: #7c8798; font-size: .68rem; line-height: 1.4; text-align: center; }
.faq-section { max-width: 1180px; margin: 70px auto 0; display: grid; grid-template-columns: .6fr 1.4fr; gap: 50px; }
.faq-section h2 { margin: 0; color: var(--navy); font-size: 2rem; letter-spacing: -.04em; }
.faq-list { border-top: 1px solid var(--line); }
.faq-list details { padding: 18px 0; border-bottom: 1px solid var(--line); }
.faq-list summary { color: var(--navy); font-weight: 800; cursor: pointer; }
.faq-list p { margin: 12px 0 0; color: var(--muted); line-height: 1.6; }
.sales-footer { max-width: 1180px; margin: 65px auto 0; padding-top: 24px; display: flex; justify-content: space-between; gap: 20px; border-top: 1px solid var(--line); color: var(--muted); font-size: .78rem; }
.sales-footer nav { display: flex; gap: 18px; }
.sales-footer a { color: var(--ink); }
.modal-copy { color: var(--muted); line-height: 1.6; }

.modal { width: min(680px, calc(100% - 28px)); padding: 0; border: 0; border-radius: 22px; background: transparent; box-shadow: 0 30px 90px rgba(0,0,0,.3); }
.modal::backdrop { background: rgba(3,12,27,.72); backdrop-filter: blur(5px); }
.modal-card { padding: clamp(24px, 5vw, 38px); border-radius: 22px; background: white; }
.modal-header { display: flex; justify-content: space-between; align-items: flex-start; gap: 16px; }
.modal-header h2 { margin: 0; color: var(--navy); font-size: 1.55rem; letter-spacing: -.035em; }
.close-button { width: 36px; height: 36px; border: 1px solid var(--line); background: white; color: var(--navy); border-radius: 9px; font-size: 1.45rem; cursor: pointer; }
.quiz-question { margin: 30px 0 18px; font-size: 1.25rem; font-weight: 800; line-height: 1.45; }
.quiz-options { display: grid; gap: 9px; }
.quiz-option { display: flex; gap: 10px; align-items: flex-start; padding: 13px; border: 1px solid var(--line); border-radius: 11px; cursor: pointer; line-height: 1.4; }
.quiz-option:has(input:checked) { border-color: var(--blue); background: #f2f6ff; }
.quiz-feedback { margin-top: 14px; padding: 12px 14px; border-radius: 10px; font-weight: 750; }
.quiz-feedback.correct { background: #ecffd1; color: #335d0a; }
.quiz-feedback.wrong { background: #fff0e8; color: #8e421a; }
.modal-actions { margin-top: 24px; display: flex; justify-content: space-between; gap: 10px; }
.offer-grid { margin: 28px 0; display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.offer-grid div { padding: 16px; border: 1px solid var(--line); border-radius: 13px; }
.offer-grid span, .positioning span { display: block; color: var(--blue); font-size: .68rem; font-weight: 850; text-transform: uppercase; letter-spacing: .08em; }
.offer-grid strong { display: block; margin: 7px 0; color: var(--navy); }
.offer-grid p { margin: 0; color: var(--muted); font-size: .8rem; line-height: 1.45; }
.positioning { padding: 17px; border-radius: 13px; background: var(--navy); color: white; }
.positioning span { color: var(--lime); }
.positioning p { margin: 8px 0 0; font-weight: 750; line-height: 1.5; }
.full-width { width: 100%; margin-top: 14px; }

@media (max-width: 980px) {
  .app-shell { grid-template-columns: 1fr; }
  .sidebar { position: fixed; z-index: 20; width: min(300px, 86vw); transform: translateX(-105%); transition: transform .25s ease; box-shadow: 25px 0 70px rgba(0,0,0,.3); }
  .sidebar.open { transform: translateX(0); }
  .mobile-menu { display: inline-flex; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; background: white; color: var(--navy); font-weight: 800; }
  .study-grid { grid-template-columns: 1fr; }
  .session-panel { min-height: 0; }
  .session-stats { max-width: 430px; }
  .timer-ring { float: right; margin-left: 20px; }
  .sales-section { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .main-area { padding: 20px 16px 34px; }
  .topbar { align-items: flex-end; margin-bottom: 20px; }
  .topbar .eyebrow { display: none; }
  .topbar h1 { font-size: 1.35rem; }
  .quiz-button { padding: 11px; font-size: .78rem; }
  .quiz-button span { display: none; }
  .flashcard { min-height: 430px; padding: 22px; border-radius: 19px; }
  .card-face { padding-top: 52px; }
  .card-face h2 { font-size: 2.5rem; }
  .practice-button { margin-left: 0; }
  .study-actions { display: grid; grid-template-columns: 1fr 1fr; }
  .value-strip { grid-template-columns: 1fr; gap: 20px; }
  .value-strip div, .value-strip div:first-child { padding: 0; border: 0; }
  .offer-grid { grid-template-columns: 1fr; }
  .demo-banner { padding-inline: 12px; justify-content: space-between; }
  .sales-section { margin-top: 45px; padding: 28px 21px; border-radius: 20px; }
  .sales-copy h2 { font-size: 2.25rem; }
  .faq-section { margin-top: 45px; grid-template-columns: 1fr; gap: 25px; }
  .sales-footer { margin-top: 45px; flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; }
}

.legal-page { background: #eef3f9; }
.legal-page main { width: min(760px, calc(100% - 32px)); margin: 0 auto; padding: 55px 0 80px; }
.legal-page h1 { margin: 0 0 30px; color: var(--navy); font-size: clamp(2.4rem, 7vw, 4.5rem); letter-spacing: -.055em; }
.legal-page h2 { margin: 30px 0 10px; color: var(--navy); font-size: 1.15rem; }
.legal-page p { color: #4f5d73; line-height: 1.7; }
.back-link { display: inline-block; margin-bottom: 48px; color: var(--navy); font-weight: 800; text-underline-offset: 4px; }
.legal-notice { margin-bottom: 30px; padding: 18px; border: 1px solid #ffd3ba; border-radius: 13px; background: #fff4ed; color: #85401b; }
.legal-notice p { margin: 6px 0 0; color: #85401b; }
.legal-footnote { margin-top: 45px; padding-top: 18px; border-top: 1px solid var(--line); font-size: .8rem; }