:root {
    --ink: #17323c;
    --muted: #66777d;
    --paper: #f7f8f6;
    --card: #ffffff;
    --green-950: #17323c;
    --green-900: #21434c;
    --green-700: #438f90;
    --green-500: #78b5b5;
    --lime: #dff0ee;
    --gold: #f2b75b;
    --red: #b84b45;
    --red-soft: #fff0ed;
    --green-soft: #edf7f4;
    --line: #dce4e2;
    --shadow: 0 18px 50px rgba(23, 50, 60, .11);
    --radius: 22px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    margin: 0;
    min-width: 320px;
    min-height: 100vh;
    background: var(--paper);
    color: var(--ink);
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    -webkit-font-smoothing: antialiased;
}
button, input, select { font: inherit; }
button { cursor: pointer; }
button:focus-visible, input:focus-visible, select:focus-visible {
    outline: 3px solid rgba(59, 139, 114, .3);
    outline-offset: 2px;
}
a { color: inherit; }
.access-link { display: inline-flex; align-items: center; justify-content: center; text-decoration: none; }
.catalog-hero { min-height: 260px; margin-bottom: 32px; }
.catalog-grid .mode-card { min-height: 250px; }
.hidden { display: none !important; }
.app-shell { min-height: 100vh; }
.loading-screen {
    min-height: 100vh;
    display: grid;
    place-content: center;
    justify-items: center;
    gap: 16px;
    color: var(--green-900);
}
.brand-mark {
    width: 52px;
    height: 52px;
    display: grid;
    place-items: center;
    border-radius: 16px;
    overflow: hidden;
    color: var(--green-950);
    background: #fff;
    font-weight: 900;
    letter-spacing: -.04em;
}
.brand-mark img { width: 72%; height: 72%; object-fit: contain; }
.topbar {
    height: 72px;
    padding: 0 clamp(18px, 4vw, 56px);
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 30;
    color: white;
    background: rgba(23, 50, 60, .97);
    backdrop-filter: blur(16px);
}
.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    font-size: 18px;
    font-weight: 800;
}
.brand .brand-mark { width: 38px; height: 38px; border-radius: 12px; font-size: 14px; }
.brand small { display: block; color: #aec5bd; font-size: 11px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; }
.user-menu { display: flex; align-items: center; gap: 12px; }
.user-email { color: #d9e5e1; font-size: 13px; max-width: 240px; overflow: hidden; text-overflow: ellipsis; }
.icon-btn, .ghost-btn {
    border: 1px solid rgba(255,255,255,.22);
    background: transparent;
    color: inherit;
    border-radius: 12px;
    min-height: 42px;
    padding: 0 14px;
    font-weight: 700;
}
.main { width: min(1180px, calc(100% - 36px)); margin: 0 auto; padding: 46px 0 70px; }
.hero {
    display: grid;
    grid-template-columns: 1.3fr .7fr;
    gap: 28px;
    align-items: stretch;
    margin-bottom: 30px;
}
.hero-copy {
    min-height: 310px;
    border-radius: 28px;
    padding: clamp(30px, 5vw, 58px);
    color: white;
    background:
        radial-gradient(circle at 85% 15%, rgba(120,181,181,.25), transparent 30%),
        linear-gradient(135deg, var(--green-950), #285b64);
    position: relative;
    overflow: hidden;
}
.eyebrow {
    margin: 0 0 15px;
    color: var(--green-500);
    font-size: 12px;
    line-height: 1;
    font-weight: 850;
    letter-spacing: .14em;
    text-transform: uppercase;
}
.hero-copy .eyebrow { color: var(--lime); }
h1, h2, h3, p { margin-top: 0; }
h1 {
    max-width: 720px;
    margin-bottom: 18px;
    font-family: Georgia, "Times New Roman", serif;
    font-size: clamp(38px, 5.4vw, 66px);
    font-weight: 500;
    line-height: .98;
    letter-spacing: -.04em;
}
.hero-copy > p:not(.eyebrow) { max-width: 620px; color: #d6e3df; font-size: 17px; line-height: 1.6; }
.official-pill {
    display: inline-flex;
    gap: 8px;
    align-items: center;
    margin-top: 12px;
    padding: 9px 12px;
    border-radius: 999px;
    background: rgba(255,255,255,.1);
    color: #e7f0ed;
    font-size: 12px;
    font-weight: 700;
}
.official-pill::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--lime); }
.readiness-card {
    border-radius: 28px;
    padding: 30px;
    background: var(--card);
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.score-ring {
    width: 150px;
    height: 150px;
    margin: 6px auto 20px;
    display: grid;
    place-items: center;
    border-radius: 50%;
    background: conic-gradient(var(--green-500) calc(var(--score, 0) * 1%), #e6ebe8 0);
    position: relative;
}
.score-ring::after { content: ""; position: absolute; inset: 11px; border-radius: 50%; background: white; }
.score-ring span { position: relative; z-index: 1; text-align: center; font-size: 34px; font-weight: 900; letter-spacing: -.05em; }
.score-ring span small { display: block; font-size: 11px; color: var(--muted); letter-spacing: .05em; text-transform: uppercase; }
.readiness-card p { color: var(--muted); line-height: 1.5; text-align: center; }
.stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    border-top: 1px solid var(--line);
    padding-top: 22px;
}
.stat { text-align: center; border-right: 1px solid var(--line); }
.stat:last-child { border-right: 0; }
.stat strong { display: block; font-size: 22px; }
.stat span { color: var(--muted); font-size: 11px; }
.section-heading {
    display: flex;
    justify-content: space-between;
    align-items: end;
    gap: 20px;
    margin: 42px 0 18px;
}
.section-heading h2 { margin: 0; font-family: Georgia, serif; font-size: clamp(27px, 3vw, 38px); font-weight: 500; letter-spacing: -.03em; }
.section-heading p { margin: 0; color: var(--muted); }
.mode-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 20px; }
.mode-card {
    min-height: 280px;
    padding: 30px;
    display: flex;
    flex-direction: column;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--card);
    box-shadow: 0 9px 30px rgba(16,41,35,.06);
}
.mode-card.featured { border: 0; color: white; background: var(--green-900); }
.mode-number { color: var(--green-500); font-size: 13px; font-weight: 900; letter-spacing: .12em; }
.featured .mode-number { color: var(--lime); }
.mode-card h3 { margin: 30px 0 12px; font-family: Georgia, serif; font-size: 31px; font-weight: 500; }
.mode-card p { color: var(--muted); line-height: 1.55; }
.featured p { color: #c6d8d2; }
.study-material-card {
    margin: 30px 0 4px;
    padding: clamp(26px, 4vw, 44px);
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 32px;
    align-items: center;
    border-radius: 26px;
    color: white;
    background:
        radial-gradient(circle at 86% 20%, rgba(223, 240, 238, .18), transparent 24%),
        linear-gradient(125deg, var(--green-950), #285b64);
    box-shadow: var(--shadow);
}
.study-material-card__copy { max-width: 760px; }
.study-material-card h2 { margin-bottom: 10px; font-family: Georgia, serif; font-size: clamp(29px, 3.4vw, 43px); font-weight: 500; }
.study-material-card p:not(.eyebrow) { margin-bottom: 18px; color: #d3e2de; line-height: 1.55; }
.study-material-card small { display: block; margin-top: 7px; color: #bdd1cb; }
.study-material-progress { height: 7px; border-radius: 999px; background: rgba(255,255,255,.16); overflow: hidden; }
.study-material-progress span { display: block; height: 100%; border-radius: inherit; background: var(--lime); }
.study-material-card .primary-btn { min-width: 220px; background: var(--lime); color: var(--green-950); }
.mode-meta { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 24px; }
.tag { padding: 7px 10px; border-radius: 9px; background: #eef2ef; color: #53605c; font-size: 12px; font-weight: 750; }
.featured .tag { background: rgba(255,255,255,.1); color: white; }
.primary-btn {
    min-height: 50px;
    padding: 0 20px;
    border: 0;
    border-radius: 13px;
    background: var(--green-700);
    color: white;
    font-weight: 850;
    box-shadow: 0 7px 18px rgba(40,103,86,.18);
}
.featured .primary-btn { margin-top: auto; background: var(--lime); color: var(--green-950); }
.secondary-btn {
    min-height: 48px;
    padding: 0 18px;
    border: 1px solid var(--line);
    border-radius: 13px;
    background: white;
    color: var(--ink);
    font-weight: 800;
}
.practice-form { margin-top: auto; display: grid; grid-template-columns: 1fr 100px; gap: 10px; }
.practice-form button { grid-column: 1 / -1; }
.field {
    width: 100%;
    min-height: 50px;
    border: 1px solid var(--line);
    border-radius: 13px;
    background: white;
    color: var(--ink);
    padding: 0 14px;
}
.themes-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 13px; }
.theme-card {
    padding: 18px;
    min-height: 138px;
    border: 1px solid var(--line);
    border-radius: 17px;
    background: rgba(255,255,255,.65);
}
.theme-card strong { display: block; color: var(--green-700); font-size: 12px; text-transform: uppercase; letter-spacing: .08em; }
.theme-card p { margin: 9px 0 13px; font-size: 13px; line-height: 1.4; }
.mini-progress { height: 6px; border-radius: 999px; background: #dfe5e1; overflow: hidden; }
.mini-progress span { display: block; height: 100%; background: var(--green-500); border-radius: inherit; }
.history-card {
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--card);
    overflow: hidden;
}
.history-row {
    display: grid;
    grid-template-columns: 1.2fr .8fr .7fr .7fr 42px;
    gap: 12px;
    align-items: center;
    width: 100%;
    padding: 17px 20px;
    border: 0;
    border-bottom: 1px solid var(--line);
    background: transparent;
    color: var(--ink);
    text-align: left;
}
.history-row:last-child { border-bottom: 0; }
.history-row:hover { background: #f8faf8; }
.history-row small { color: var(--muted); }
.status { justify-self: start; padding: 6px 9px; border-radius: 999px; font-size: 11px; font-weight: 850; }
.status.pass { color: #24614d; background: var(--green-soft); }
.status.fail { color: #9c3e39; background: var(--red-soft); }
.empty-state { padding: 34px; text-align: center; color: var(--muted); }
.site-footer { margin-top: 60px; padding-top: 25px; border-top: 1px solid var(--line); color: var(--muted); font-size: 12px; line-height: 1.6; }
.site-footer a { color: var(--green-700); font-weight: 700; }

.login-page {
    min-height: 100vh;
    display: grid;
    grid-template-columns: 1.08fr .92fr;
    background: var(--green-950);
}
.login-story {
    padding: clamp(38px, 7vw, 90px);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    color: white;
    background:
        radial-gradient(circle at 10% 90%, rgba(120,181,181,.2), transparent 32%),
        linear-gradient(145deg, #17323c, #285b64);
}
.login-story h1 { max-width: 720px; margin-top: 70px; }
.login-story > div > p { max-width: 600px; color: #cadbd6; font-size: 17px; line-height: 1.6; }
.exam-facts { display: flex; gap: 32px; flex-wrap: wrap; }
.exam-facts strong { display: block; color: var(--lime); font-family: Georgia, serif; font-size: 30px; font-weight: 500; }
.exam-facts span { color: #b8ccc6; font-size: 12px; }
.login-panel {
    padding: 30px;
    display: grid;
    place-items: center;
    background: var(--paper);
}
.login-card { width: min(470px, 100%); padding: clamp(28px, 6vw, 48px); border-radius: 28px; background: white; box-shadow: var(--shadow); }
.login-card h2 { margin-bottom: 12px; font-family: Georgia, serif; font-size: 36px; font-weight: 500; letter-spacing: -.03em; }
.login-card > p { color: var(--muted); line-height: 1.55; }
.login-form { margin-top: 30px; }
.login-form label { display: block; margin-bottom: 8px; font-size: 13px; font-weight: 800; }
.login-form .field { min-height: 56px; }
.login-form .primary-btn { width: 100%; min-height: 56px; margin-top: 12px; }
.privacy-note { margin: 18px 0 0 !important; font-size: 11px; line-height: 1.55 !important; }
.error-text { min-height: 20px; margin: 8px 0 0; color: var(--red); font-size: 12px; }

.exam-shell { min-height: 100vh; background: #f3f2ec; }
.exam-topbar { position: sticky; top: 0; z-index: 30; background: white; border-bottom: 1px solid var(--line); }
.exam-topbar-inner {
    min-height: 72px;
    width: min(1240px, calc(100% - 34px));
    margin: auto;
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    gap: 18px;
}
.exam-title strong { display: block; }
.exam-title span { color: var(--muted); font-size: 12px; }
.timer {
    min-width: 104px;
    padding: 10px 14px;
    border-radius: 13px;
    background: var(--green-950);
    color: white;
    text-align: center;
    font-variant-numeric: tabular-nums;
    font-size: 20px;
    font-weight: 850;
}
.timer.warning { color: #2c2411; background: var(--gold); }
.exit-btn { justify-self: end; color: var(--muted); border-color: var(--line); }
.progress-track { height: 4px; background: #e2e7e4; }
.progress-track span { display: block; height: 100%; background: var(--green-500); transition: width .25s; }
.exam-layout {
    width: min(1240px, calc(100% - 34px));
    margin: 0 auto;
    padding: 36px 0 46px;
    display: grid;
    grid-template-columns: minmax(0, 1fr) 285px;
    gap: 24px;
}
.question-card { min-height: 590px; padding: clamp(24px, 4vw, 46px); border-radius: 24px; background: white; box-shadow: 0 10px 35px rgba(16,41,35,.06); }
.question-kicker { display: flex; justify-content: space-between; gap: 15px; color: var(--green-700); font-size: 12px; font-weight: 850; letter-spacing: .08em; text-transform: uppercase; }
.flag-btn { border: 0; background: transparent; color: var(--muted); font-weight: 750; }
.flag-btn.active { color: #9a6b17; }
.question-card h1 { margin: 34px 0 32px; font-family: Georgia, serif; font-size: clamp(25px, 3.2vw, 39px); line-height: 1.2; letter-spacing: -.025em; }
.answers { display: grid; gap: 12px; }
.answer {
    width: 100%;
    min-height: 70px;
    padding: 15px 18px;
    display: grid;
    grid-template-columns: 36px 1fr;
    gap: 14px;
    align-items: center;
    border: 1px solid var(--line);
    border-radius: 15px;
    background: white;
    color: var(--ink);
    text-align: left;
    line-height: 1.45;
    transition: border-color .18s, background .18s, transform .18s;
}
.answer:hover { border-color: var(--green-500); transform: translateY(-1px); }
.answer.selected { border-color: var(--green-500); background: var(--green-soft); box-shadow: inset 0 0 0 1px var(--green-500); }
.answer.reading { cursor: default; }
.answer.reading:hover { border-color: var(--line); transform: none; }
.answer.reading-correct {
    border-color: var(--green-500);
    background: var(--green-soft);
    box-shadow: inset 0 0 0 1px var(--green-500);
    color: #205c48;
    font-weight: 750;
}
.answer-key { width: 34px; height: 34px; display: grid; place-items: center; border: 1px solid var(--line); border-radius: 10px; color: var(--muted); font-weight: 850; }
.answer.selected .answer-key { border-color: var(--green-700); background: var(--green-700); color: white; }
.answer.reading-correct .answer-key { border-color: var(--green-700); background: var(--green-700); color: white; }
.question-actions { display: flex; justify-content: space-between; gap: 12px; margin-top: 34px; }
.question-actions .primary-btn, .question-actions .secondary-btn { min-width: 126px; }
.question-nav { position: sticky; top: 108px; align-self: start; padding: 22px; border-radius: 20px; background: white; }
.question-nav h3 { margin-bottom: 4px; font-size: 15px; }
.question-nav > p { color: var(--muted); font-size: 12px; }
.question-dots {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
    max-height: 390px;
    margin: 20px 0;
    padding-right: 3px;
    overflow-y: auto;
}
.question-dot { aspect-ratio: 1; border: 1px solid var(--line); border-radius: 9px; background: white; color: var(--muted); font-size: 12px; font-weight: 800; }
.question-dot.current { border-color: var(--green-900); box-shadow: inset 0 0 0 2px var(--green-900); }
.question-dot.answered { background: var(--green-soft); color: var(--green-700); border-color: #b8ddce; }
.question-dot.flagged::after { content: "•"; color: #b9801d; }
.submit-btn { width: 100%; }
.nav-legend { display: flex; flex-wrap: wrap; gap: 10px; color: var(--muted); font-size: 10px; }
.nav-legend i { width: 8px; height: 8px; display: inline-block; border-radius: 3px; background: var(--line); }
.nav-legend i.done { background: #8dc9b2; }
.nav-legend i.flag { background: var(--gold); }

.result-hero {
    padding: 42px clamp(22px, 5vw, 60px);
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 30px;
    align-items: center;
    border-radius: 26px;
    color: white;
    background: var(--green-950);
}
.result-score { font-family: Georgia, serif; font-size: clamp(54px, 8vw, 84px); line-height: 1; }
.result-score small { display: block; color: #aec6be; font-family: Inter, sans-serif; font-size: 11px; letter-spacing: .1em; text-transform: uppercase; }
.result-hero h1 { margin: 0 0 8px; font-size: clamp(30px, 4vw, 48px); }
.result-hero p { margin: 0; color: #c6d7d1; }
.result-badge { padding: 10px 15px; border-radius: 999px; background: var(--lime); color: var(--green-950); font-weight: 900; }
.result-badge.fail { background: #ffd1c9; color: #7e2b27; }
.result-toolbar { margin: 26px 0 18px; display: flex; justify-content: space-between; align-items: center; gap: 15px; flex-wrap: wrap; }
.filters { display: flex; gap: 8px; flex-wrap: wrap; }
.filter-btn { padding: 9px 13px; border: 1px solid var(--line); border-radius: 999px; background: white; color: var(--muted); font-weight: 750; }
.filter-btn.active { background: var(--green-900); color: white; border-color: var(--green-900); }
.review-list { display: grid; gap: 14px; }
.review-item { padding: 24px; border: 1px solid var(--line); border-radius: 18px; background: white; }
.review-item.wrong { border-left: 5px solid var(--red); }
.review-item.right { border-left: 5px solid var(--green-500); }
.review-meta { display: flex; justify-content: space-between; gap: 12px; color: var(--muted); font-size: 11px; font-weight: 750; text-transform: uppercase; letter-spacing: .06em; }
.review-item h3 { margin: 14px 0 18px; font-size: 17px; line-height: 1.45; }
.review-answer { padding: 11px 13px; margin-top: 7px; border-radius: 10px; background: #f5f6f4; font-size: 13px; line-height: 1.4; }
.review-answer.correct { color: #205c48; background: var(--green-soft); font-weight: 750; }
.review-answer.selected-wrong { color: #913933; background: var(--red-soft); }
.source-note { margin: 13px 0 0; color: var(--muted); font-size: 11px; }
.source-note a { color: var(--green-700); }
.toast { position: fixed; left: 50%; bottom: 28px; z-index: 60; transform: translateX(-50%); padding: 13px 18px; border-radius: 12px; background: #17211e; color: white; box-shadow: var(--shadow); font-size: 13px; }

.book-reader {
    height: 100dvh;
    min-height: 620px;
    overflow: hidden;
    background: #eef1ed;
}
.book-reader__header {
    height: 72px;
    padding: 0 clamp(16px, 3vw, 42px);
    display: grid;
    grid-template-columns: minmax(220px, 1fr) minmax(180px, 360px) minmax(160px, 1fr);
    gap: 24px;
    align-items: center;
    color: white;
    background: var(--green-950);
}
.book-reader__header .ghost-btn { justify-self: end; }
.book-reader__position { text-align: center; font-size: 12px; font-weight: 750; }
.book-reader__position > div { height: 5px; margin-top: 7px; border-radius: 999px; overflow: hidden; background: rgba(255,255,255,.16); }
.book-reader__position i { display: block; height: 100%; border-radius: inherit; background: var(--green-500); }
.book-reader__layout {
    height: calc(100dvh - 72px);
    min-height: 548px;
    display: grid;
    grid-template-columns: 310px minmax(0, 1fr);
}
.book-index {
    padding: 28px 20px 34px;
    overflow-y: auto;
    border-right: 1px solid var(--line);
    background: #f8faf7;
}
.book-index__head { display: flex; align-items: center; justify-content: space-between; }
.book-index__head button { display: none; border: 0; background: transparent; color: var(--muted); font-size: 28px; }
.book-index h2 { margin: 4px 6px 24px; font-family: Georgia, serif; font-size: 23px; font-weight: 500; line-height: 1.15; }
.book-index__chapter {
    width: 100%;
    padding: 11px 9px;
    display: grid;
    grid-template-columns: 30px 1fr auto;
    gap: 9px;
    align-items: center;
    border: 0;
    border-radius: 12px;
    background: transparent;
    color: var(--ink);
    text-align: left;
}
.book-index__chapter > span { color: var(--green-700); font-size: 11px; font-weight: 900; }
.book-index__chapter strong { font-size: 12px; line-height: 1.25; }
.book-index__chapter small { color: var(--muted); font-size: 9px; }
.book-index__chapter:hover, .book-index__chapter.active { background: var(--lime); }
.book-stage {
    min-width: 0;
    padding: clamp(18px, 3vw, 34px) clamp(18px, 4vw, 58px) 92px;
    display: grid;
    grid-template-rows: auto minmax(0, 1fr);
    gap: 12px;
}
.book-index-toggle { display: none; justify-self: start; padding: 8px 12px; border: 1px solid var(--line); border-radius: 10px; background: white; color: var(--ink); font-weight: 800; }
.book-sheet {
    width: min(900px, 100%);
    min-height: 0;
    margin: 0 auto;
    padding: clamp(28px, 5vh, 56px) clamp(26px, 6vw, 78px);
    overflow: hidden;
    border: 1px solid #d9dfda;
    border-radius: 6px 24px 24px 6px;
    background:
        linear-gradient(90deg, rgba(23,50,60,.055), transparent 30px),
        #fff;
    box-shadow: 0 20px 55px rgba(23,50,60,.12);
}
.book-page { height: 100%; display: flex; flex-direction: column; justify-content: center; }
.book-page h1 { max-width: 760px; margin-bottom: clamp(15px, 2.6vh, 28px); font-size: clamp(31px, 4.8vh, 53px); line-height: 1.02; }
.book-page__lead { max-width: 720px; color: var(--muted); font-size: clamp(15px, 1.9vh, 19px); line-height: 1.55; }
.book-page__mark { width: 64px; height: 64px; margin-bottom: 28px; display: grid; place-items: center; border-radius: 20px; color: white; background: var(--green-700); font-family: Georgia, serif; font-size: 25px; }
.book-page--cover { padding-right: 10%; }
.book-page--cover h1 { font-size: clamp(38px, 6.2vh, 66px); }
.book-page__cover-meta { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 24px; }
.book-page__cover-meta span { padding: 8px 11px; border-radius: 999px; background: var(--lime); color: var(--green-900); font-size: 11px; font-weight: 800; }
.book-highlights { max-width: 710px; margin: 12px 0 0; padding: 0; display: grid; grid-template-columns: 1fr 1fr; gap: 10px; list-style: none; }
.book-highlights li { padding: 13px 15px; border-radius: 13px; background: #f2f6f3; color: var(--ink); font-size: 13px; line-height: 1.35; }
.book-concepts { display: grid; gap: clamp(14px, 2.5vh, 26px); }
.book-concepts section { padding-top: clamp(13px, 2vh, 22px); border-top: 1px solid var(--line); }
.book-concepts h2 { margin-bottom: 8px; font-family: Georgia, serif; font-size: clamp(21px, 2.9vh, 30px); font-weight: 500; line-height: 1.15; }
.book-concepts p { margin-bottom: 12px; color: var(--muted); font-size: clamp(13px, 1.65vh, 16px); line-height: 1.5; }
.book-action { padding: 11px 14px; display: grid; grid-template-columns: auto 1fr; gap: 12px; border-radius: 12px; background: var(--green-soft); font-size: clamp(12px, 1.5vh, 14px); line-height: 1.4; }
.book-action strong { color: var(--green-700); white-space: nowrap; }
.book-checklist { max-width: 740px; margin: 8px 0 0; padding: 0; display: grid; gap: 8px; list-style: none; }
.book-checklist li { padding: 10px 13px; display: grid; grid-template-columns: 24px 1fr; gap: 10px; align-items: start; border-radius: 12px; background: #f4f7f4; font-size: clamp(12px, 1.55vh, 14px); line-height: 1.38; }
.book-checklist li span { color: var(--green-700); font-weight: 900; }
.book-page--closing { align-items: flex-start; }
.book-page--closing .primary-btn { margin-top: 18px; }
.book-navigation {
    position: fixed;
    z-index: 45;
    left: 310px;
    right: 0;
    bottom: 0;
    min-height: 76px;
    padding: 12px clamp(18px, 4vw, 58px);
    display: grid;
    grid-template-columns: 150px 1fr 150px;
    gap: 14px;
    align-items: center;
    border-top: 1px solid rgba(23, 50, 60, .1);
    background: rgba(247, 249, 246, .96);
    box-shadow: 0 -10px 30px rgba(23, 50, 60, .06);
    backdrop-filter: blur(14px);
}
.book-navigation > span { overflow: hidden; color: var(--muted); text-align: center; text-overflow: ellipsis; white-space: nowrap; font-size: 12px; }
.book-navigation button { min-width: 0; }

@media (max-width: 900px) {
    .hero, .login-page { grid-template-columns: 1fr; }
    .login-story { min-height: 52vh; }
    .login-story h1 { margin-top: 45px; }
    .mode-grid { grid-template-columns: 1fr; }
    .themes-grid { grid-template-columns: repeat(2, 1fr); }
    .exam-layout { grid-template-columns: 1fr; }
    .question-nav { position: static; }
    .result-hero { grid-template-columns: auto 1fr; }
    .result-badge { grid-column: 1 / -1; justify-self: start; }
    .study-material-card { grid-template-columns: 1fr; }
    .study-material-card .primary-btn { justify-self: start; }
    .book-reader__layout { grid-template-columns: 1fr; }
    .book-index {
        position: fixed;
        z-index: 80;
        inset: 72px auto 0 0;
        width: min(340px, 90vw);
        transform: translateX(-105%);
        box-shadow: 20px 0 50px rgba(23,50,60,.2);
        transition: transform .2s ease;
    }
    .book-index.open { transform: translateX(0); }
    .book-index__head button, .book-index-toggle { display: block; }
    .book-navigation { left: 0; }
}
@media (max-width: 640px) {
    .topbar { height: 64px; }
    .brand small, .user-email { display: none; }
    .main { width: min(100% - 24px, 1180px); padding-top: 20px; }
    .hero-copy, .readiness-card { border-radius: 21px; }
    .hero-copy { min-height: auto; padding: 30px 24px; }
    .hero-copy h1 { font-size: 39px; }
    .readiness-card { padding: 23px; }
    .themes-grid { grid-template-columns: 1fr; }
    .history-row { grid-template-columns: 1fr auto; padding: 16px; }
    .history-row > *:nth-child(2), .history-row > *:nth-child(4) { display: none; }
    .history-row > *:last-child { display: none; }
    .section-heading { align-items: start; flex-direction: column; }
    .login-story { min-height: 54vh; padding: 30px 24px; }
    .login-story h1 { margin-top: 50px; font-size: 42px; }
    .login-panel { padding: 18px; }
    .login-card { padding: 28px 22px; border-radius: 22px; }
    .exam-topbar-inner { width: calc(100% - 24px); grid-template-columns: 1fr auto; min-height: 64px; }
    .exam-title span { display: none; }
    .timer { min-width: 88px; font-size: 17px; }
    .exit-btn { display: none; }
    .exam-layout { width: calc(100% - 20px); padding: 12px 0 108px; }
    .question-card { min-height: auto; padding: 23px 18px; border-radius: 18px; }
    .question-card h1 { margin: 26px 0 24px; font-size: 25px; }
    .answer { min-height: 64px; padding: 12px; grid-template-columns: 32px 1fr; }
    .question-actions { position: fixed; z-index: 25; left: 0; right: 0; bottom: 0; margin: 0; padding: 10px 12px calc(10px + env(safe-area-inset-bottom)); background: rgba(255,255,255,.97); border-top: 1px solid var(--line); }
    .question-actions button { flex: 1; min-width: 0 !important; }
    .question-nav { display: none; }
    .result-hero { padding: 28px 22px; gap: 18px; }
    .result-score { font-size: 55px; }
    .result-hero h1 { font-size: 30px; }
    .result-toolbar .secondary-btn { width: 100%; }
    .study-material-card { padding: 25px 21px; gap: 20px; }
    .study-material-card .primary-btn { width: 100%; }
    .book-reader { min-height: 560px; }
    .book-reader__header { height: 64px; grid-template-columns: 1fr auto; gap: 12px; }
    .book-reader__header .brand small, .book-reader__header .ghost-btn { display: none; }
    .book-reader__position { width: 125px; }
    .book-reader__layout { height: calc(100dvh - 64px); min-height: 496px; }
    .book-index { top: 64px; }
    .book-stage { padding: 10px 10px calc(82px + env(safe-area-inset-bottom)); gap: 8px; }
    .book-index-toggle { font-size: 12px; }
    .book-sheet { padding: 22px 20px; border-radius: 5px 17px 17px 5px; }
    .book-page h1 { font-size: clamp(28px, 5.4vh, 38px); }
    .book-page__lead { font-size: clamp(13px, 2.2vh, 16px); }
    .book-page__mark { width: 48px; height: 48px; margin-bottom: 16px; border-radius: 15px; font-size: 19px; }
    .book-page--cover { padding-right: 0; }
    .book-highlights { grid-template-columns: 1fr; gap: 6px; }
    .book-highlights li:nth-child(n+4) { display: none; }
    .book-concepts { gap: 10px; }
    .book-concepts h2 { font-size: clamp(19px, 3.2vh, 24px); }
    .book-action { grid-template-columns: 1fr; gap: 3px; }
    .book-checklist li:nth-child(n+5) { display: none; }
    .book-navigation { min-height: 70px; padding: 9px 10px calc(9px + env(safe-area-inset-bottom)); grid-template-columns: 1fr 1fr; gap: 8px; }
    .book-navigation > span { display: none; }
}
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; }
}