:root {
    color-scheme: light;
    --primary: #0f766e;
    --primary-dark: #115e59;
    --primary-soft: #e6f5f3;
    --accent: #f59e0b;
    --success: #15803d;
    --success-soft: #ecfdf3;
    --danger: #b91c1c;
    --danger-soft: #fff1f2;
    --info: #2563eb;
    --surface: #ffffff;
    --background: #f4f7f7;
    --background-strong: #eaf0ef;
    --text: #14201f;
    --muted: #64748b;
    --border: #d9e2e1;
    --border-strong: #b7c8c6;
    --shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
    --shadow-lg: 0 20px 48px rgba(15, 23, 42, 0.12);
    --radius-sm: 10px;
    --radius-card: 16px;
    --radius-panel: 20px;
    --sidebar: 264px;
}

* { box-sizing: border-box; }

html { min-width: 320px; background: var(--background); }

body {
    margin: 0;
    min-height: 100vh;
    color: var(--text);
    background:
        radial-gradient(circle at 86% 4%, rgba(15, 118, 110, 0.09), transparent 28rem),
        var(--background);
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    font-size: 16px;
    line-height: 1.5;
}

button, input, select { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: inherit; }
button { color: inherit; }

button:focus-visible,
a:focus-visible,
input:focus-visible,
select:focus-visible {
    outline: 2px solid var(--info);
    outline-offset: 3px;
}

.skip-link {
    position: fixed;
    z-index: 1000;
    top: 8px;
    left: 8px;
    padding: 10px 14px;
    border-radius: 8px;
    color: #fff;
    background: var(--primary-dark);
    transform: translateY(-150%);
}
.skip-link:focus { transform: translateY(0); }

.loading-screen {
    min-height: 100vh;
    display: grid;
    place-content: center;
    justify-items: center;
    color: var(--muted);
}

.brand-mark {
    width: 44px;
    height: 44px;
    display: grid;
    place-items: center;
    border-radius: 14px 14px 14px 4px;
    color: #fff;
    background: var(--primary);
    font-size: 22px;
    font-weight: 900;
    box-shadow: var(--shadow);
}

.brand-lockup { display: flex; align-items: center; gap: 12px; text-decoration: none; }
.brand-copy { display: grid; line-height: 1.12; }
.brand-copy strong { font-size: 14px; }
.brand-copy span { color: var(--muted); font-size: 12px; }

.eyebrow {
    margin: 0 0 8px;
    color: var(--primary);
    font-size: 12px;
    font-weight: 800;
    letter-spacing: .12em;
    text-transform: uppercase;
}

h1, h2, h3, p { margin-top: 0; }
h1 { margin-bottom: 16px; font-size: clamp(32px, 4vw, 48px); line-height: 1.08; letter-spacing: -.035em; }
h2 { margin-bottom: 14px; font-size: clamp(24px, 3vw, 32px); line-height: 1.15; letter-spacing: -.025em; }
h3 { margin-bottom: 10px; font-size: 19px; line-height: 1.25; }
.lead { max-width: 680px; color: #465a58; font-size: clamp(17px, 2vw, 20px); }
.muted { color: var(--muted); }
.small { font-size: 13px; }

.button {
    min-height: 48px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 9px;
    padding: 11px 18px;
    border: 1px solid transparent;
    border-radius: 12px;
    cursor: pointer;
    text-decoration: none;
    font-weight: 750;
    transition: transform .16s ease, box-shadow .16s ease, background .16s ease;
}
.button:hover { transform: translateY(-1px); }
.button-primary { color: #fff; background: var(--primary); box-shadow: 0 8px 18px rgba(15,118,110,.18); }
.button-primary:hover { background: var(--primary-dark); }
.button-secondary { border-color: var(--border); background: var(--surface); }
.button-secondary:hover { border-color: var(--primary); color: var(--primary-dark); }
.button-danger { color: #fff; background: var(--danger); }
.button-ghost { min-height: 44px; padding: 8px 12px; border-color: transparent; color: var(--primary-dark); background: transparent; }
.button:disabled { opacity: .55; cursor: wait; transform: none; }
.button-block { width: 100%; }

.card {
    border: 1px solid var(--border);
    border-radius: var(--radius-card);
    background: var(--surface);
    box-shadow: var(--shadow);
}
.panel { padding: clamp(20px, 3vw, 32px); }

.badge {
    display: inline-flex;
    align-items: center;
    min-height: 26px;
    padding: 4px 9px;
    border: 1px solid transparent;
    border-radius: 999px;
    font-size: 12px;
    font-weight: 750;
    line-height: 1;
}
.badge-category { color: var(--primary-dark); background: var(--primary-soft); border-color: #bfe2dd; }
.badge-dlt_verified { color: #166534; background: #dcfce7; border-color: #bbf7d0; }
.badge-dlt_based { color: var(--primary-dark); background: #e6fffb; border-color: #b8e8e2; }
.badge-community_verified { color: #1d4ed8; background: #eff6ff; border-color: #bfdbfe; }
.badge-official_verified { color: #166534; background: #dcfce7; border-color: #a7e3b6; }
.badge-official_based { color: #075985; background: #e0f2fe; border-color: #bae6fd; }
.badge-third_party_verified { color: #5b21b6; background: #f5f3ff; border-color: #ddd6fe; }
.badge-needs_review, .badge-legacy_unverified { color: #92400e; background: #fffbeb; border-color: #fde68a; }

.notice {
    padding: 14px 16px;
    border: 1px solid #f4d286;
    border-radius: 12px;
    color: #744a08;
    background: #fffaf0;
    font-size: 13px;
}
.error-notice { border-color: #fecaca; color: var(--danger); background: var(--danger-soft); }

/* Shared navigation */
.desktop-shell { min-height: 100vh; display: grid; grid-template-columns: var(--sidebar) minmax(0, 1fr); }
.desktop-sidebar {
    position: sticky;
    top: 0;
    height: 100vh;
    display: flex;
    flex-direction: column;
    padding: 28px 20px;
    border-right: 1px solid var(--border);
    background: rgba(255,255,255,.88);
    backdrop-filter: blur(18px);
}
.desktop-nav { display: grid; gap: 4px; margin-top: 32px; }
.nav-section { margin: 20px 12px 6px; color: #8a9998; font-size: 10px; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
.nav-link {
    min-height: 44px;
    display: flex;
    align-items: center;
    gap: 11px;
    padding: 10px 12px;
    border-radius: 11px;
    color: #526563;
    text-decoration: none;
    font-size: 14px;
    font-weight: 650;
}
.nav-link:hover, .nav-link.active { color: var(--primary-dark); background: var(--primary-soft); }
.nav-symbol { width: 24px; color: var(--primary); text-align: center; font-weight: 850; }
.sidebar-note { margin-top: auto; padding: 14px; border-radius: 12px; color: var(--muted); background: var(--background); font-size: 12px; }
.desktop-content { min-width: 0; padding: clamp(28px, 4vw, 58px); }

.tablet-shell { min-height: 100vh; background: var(--background); }
.tablet-header {
    position: sticky;
    z-index: 45;
    top: 0;
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    align-items: center;
    gap: 22px;
    padding: 14px 22px;
    border-bottom: 1px solid var(--border);
    background: rgba(255,255,255,.96);
    backdrop-filter: blur(18px);
}
.tablet-nav { min-width: 0; display: flex; justify-content: flex-end; gap: 4px; overflow-x: auto; }
.tablet-nav-link { min-height: 46px; display: inline-flex; align-items: center; padding: 8px 11px; border-radius: 10px; color: var(--muted); font-size: 13px; font-weight: 750; text-decoration: none; white-space: nowrap; }
.tablet-nav-link:hover, .tablet-nav-link.active { color: var(--primary-dark); background: var(--primary-soft); }
.tablet-content { min-width: 0; padding: 34px 28px 52px; }
.tablet-home-grid { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(280px, .8fr); gap: 20px; align-items: stretch; margin-top: 22px; }
.tablet-home-grid .sign-home-feature { height: 100%; margin-top: 0; }
.tablet-answer-key-tools { padding: 20px; }
.tablet-answer-key-tools .answer-key-controls { grid-template-columns: minmax(0, 1fr) minmax(180px, .5fr); align-items: end; }
.tablet-answer-key-tools .answer-key-match-count, .tablet-answer-key-tools .answer-key-control-actions { grid-column: 1 / -1; }
.tablet-answer-key-tools .answer-key-control-actions { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.tablet-answer-key-jumps { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; margin: 14px 0 24px; }

.mobile-shell { min-height: 100vh; padding-bottom: 86px; }
.mobile-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 18px;
    border-bottom: 1px solid var(--border);
    background: rgba(255,255,255,.92);
}
.mobile-content { padding: 22px 18px 34px; }
.mobile-bottom-nav {
    position: fixed;
    z-index: 40;
    inset: auto 0 0;
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    padding: 8px max(8px, env(safe-area-inset-right)) calc(8px + env(safe-area-inset-bottom)) max(8px, env(safe-area-inset-left));
    border-top: 1px solid var(--border);
    background: rgba(255,255,255,.96);
    backdrop-filter: blur(18px);
}
.mobile-nav-link {
    min-height: 54px;
    display: grid;
    place-items: center;
    gap: 2px;
    border-radius: 10px;
    color: var(--muted);
    text-decoration: none;
    font-size: 10px;
    font-weight: 700;
}
.mobile-nav-link strong { font-size: 17px; line-height: 1; }
.mobile-nav-link.active { color: var(--primary-dark); background: var(--primary-soft); }

/* Home */
.hero-panel {
    position: relative;
    overflow: hidden;
    padding: clamp(28px, 5vw, 58px);
    border-radius: clamp(20px, 3vw, 30px);
    color: #f7fffe;
    background: linear-gradient(135deg, #0b5f59 0%, #0f766e 58%, #239b8f 100%);
    box-shadow: var(--shadow-lg);
}
.hero-panel::after {
    content: "";
    position: absolute;
    right: -80px;
    bottom: -110px;
    width: 300px;
    height: 300px;
    border: 50px solid rgba(255,255,255,.07);
    border-radius: 50%;
}
.hero-panel .eyebrow { color: #a7f3d0; }
.hero-panel h1 { max-width: 760px; }
.hero-panel .lead { color: rgba(255,255,255,.78); }
.hero-actions { position: relative; z-index: 1; display: flex; flex-wrap: wrap; gap: 12px; margin-top: 26px; }
.hero-actions .button-primary { color: var(--primary-dark); background: #fff; }
.hero-actions .button-secondary { color: #fff; border-color: rgba(255,255,255,.38); background: rgba(255,255,255,.1); }
.home-grid { display: grid; grid-template-columns: minmax(0, 1.55fr) minmax(280px, .65fr); gap: 22px; margin-top: 22px; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 16px; margin: 34px 0 16px; }
.section-heading h2 { margin: 0; font-size: 25px; }
.category-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; }
.category-card { min-height: 118px; display: flex; flex-direction: column; padding: 18px; text-decoration: none; transition: transform .16s ease, border-color .16s ease; }
.category-card:hover { transform: translateY(-2px); border-color: var(--primary); }
.category-initial { width: 36px; height: 36px; display: grid; place-items: center; margin-bottom: 15px; border-radius: 10px; color: var(--primary-dark); background: var(--primary-soft); font-size: 12px; font-weight: 900; }
.category-card strong { line-height: 1.2; }
.category-card span { margin-top: 5px; color: var(--muted); font-size: 12px; }
.stats-stack { display: grid; gap: 12px; }
.stat-card { padding: 18px; }
.stat-card .value { display: block; margin-top: 6px; font-size: 28px; font-weight: 850; letter-spacing: -.04em; }
.stat-card .label { color: var(--muted); font-size: 13px; }
.stat-card.accent { color: #fff; border-color: transparent; background: var(--primary-dark); }
.stat-card.accent .label { color: rgba(255,255,255,.7); }
.metric-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }

/* Forms and practice */
.page-header { margin-bottom: 26px; }
.page-header h1 { font-size: clamp(30px, 4vw, 42px); }
.filter-panel { padding: 20px; }
.filter-grid { display: grid; gap: 14px; }
.field { display: grid; gap: 6px; }
.field label { color: #425553; font-size: 13px; font-weight: 700; }
.field input, .field select {
    min-height: 46px;
    width: 100%;
    padding: 9px 12px;
    border: 1px solid var(--border-strong);
    border-radius: 10px;
    color: var(--text);
    background: #fff;
}
.checkbox-field { min-height: 44px; display: flex; align-items: center; gap: 10px; }
.checkbox-field input { width: 19px; height: 19px; accent-color: var(--primary); }
.practice-layout { display: grid; grid-template-columns: minmax(220px, 290px) minmax(0, 1fr); gap: 22px; align-items: start; }
.practice-main { display: grid; gap: 18px; }

.question-card { padding: clamp(22px, 3vw, 36px); }
.question-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin-bottom: 20px; }
.question-number { margin-left: auto; color: var(--muted); font-size: 13px; font-weight: 700; }
.question-text { max-width: 850px; margin-bottom: 24px; font-size: clamp(20px, 2.3vw, 28px); line-height: 1.35; }
.question-image { width: 100%; max-height: 360px; margin-bottom: 22px; border-radius: 14px; object-fit: contain; background: var(--background); }
.answer-list { display: grid; gap: 12px; }
.answer-option {
    width: 100%;
    min-height: 58px;
    display: grid;
    grid-template-columns: 38px minmax(0, 1fr);
    align-items: center;
    gap: 12px;
    padding: 11px 14px;
    border: 1px solid var(--border);
    border-radius: 13px;
    color: var(--text);
    background: #fff;
    cursor: pointer;
    text-align: left;
    transition: border-color .15s ease, background .15s ease;
}
.answer-content { min-width: 0; display: grid; gap: 10px; }
.answer-image { display: block; max-width: min(100%, 420px); max-height: 240px; object-fit: contain; border-radius: 10px; }
.answer-option:hover { border-color: var(--primary); background: #fbfefd; }
.answer-option.selected { border-color: var(--primary); background: var(--primary-soft); }
.answer-option.correct { border-color: #86d39b; background: var(--success-soft); }
.answer-option.incorrect { border-color: #f2aaaa; background: var(--danger-soft); }
.answer-marker { width: 34px; height: 34px; display: grid; place-items: center; border: 1px solid var(--border-strong); border-radius: 9px; font-weight: 850; }
.answer-option.selected .answer-marker { color: #fff; border-color: var(--primary); background: var(--primary); }
.answer-option.correct .answer-marker { color: #fff; border-color: var(--success); background: var(--success); }
.answer-option.incorrect .answer-marker { color: #fff; border-color: var(--danger); background: var(--danger); }
.question-actions { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-top: 24px; }
.feedback-card { padding: 22px; border-left: 5px solid var(--success); }
.feedback-card.incorrect-feedback { border-left-color: var(--danger); }
.feedback-title { color: var(--success); font-size: 18px; font-weight: 850; }
.incorrect-feedback .feedback-title { color: var(--danger); }
.source-line { margin-top: 16px; padding-top: 14px; border-top: 1px solid var(--border); color: var(--muted); font-size: 13px; }
.source-line a { color: var(--primary-dark); font-weight: 700; }

/* Exam */
.exam-topbar { display: flex; align-items: center; justify-content: space-between; gap: 16px; margin-bottom: 18px; }
.exam-progress,
.performance-bar { width: 100%; height: 8px; overflow: hidden; border: 0; border-radius: 999px; appearance: none; background: #deebe9; }
.exam-progress::-webkit-progress-bar,
.performance-bar::-webkit-progress-bar { border-radius: 999px; background: #deebe9; }
.exam-progress::-webkit-progress-value,
.performance-bar::-webkit-progress-value { border-radius: 999px; background: var(--primary); transition: width .2s ease; }
.exam-progress::-moz-progress-bar,
.performance-bar::-moz-progress-bar { border-radius: 999px; background: var(--primary); }
.exam-progress-spacer { height: 16px; }
.timer { font-variant-numeric: tabular-nums; font-size: 30px; font-weight: 850; letter-spacing: -.04em; }
.timer.warning { color: var(--danger); }
.desktop-exam-layout, .tablet-exam-layout { display: grid; gap: 22px; align-items: start; }
.desktop-exam-layout { grid-template-columns: minmax(0, 1fr) 314px; }
.tablet-exam-layout { grid-template-columns: minmax(0, 1.9fr) minmax(260px, 1fr); }
.exam-context { position: sticky; top: 24px; padding: 22px; }
.context-heading { display: flex; align-items: center; justify-content: space-between; gap: 10px; }
.context-counts { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin: 18px 0; }
.context-count { padding: 12px; border-radius: 11px; background: var(--background); }
.context-count strong { display: block; font-size: 23px; }
.context-count span { color: var(--muted); font-size: 11px; }
.navigator-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 7px; margin: 18px 0; }
.navigator-button { min-width: 0; aspect-ratio: 1; border: 1px solid var(--border); border-radius: 9px; background: #fff; cursor: pointer; font-size: 12px; font-weight: 750; }
.navigator-button.answered { color: var(--primary-dark); border-color: #9fd7d1; background: var(--primary-soft); }
.navigator-button.current { color: #fff; border-color: var(--primary); background: var(--primary); }
.exam-question-actions { display: flex; justify-content: space-between; gap: 12px; margin-top: 24px; }

.mobile-exam { min-height: 100vh; padding: 0 0 86px; background: var(--background); }
.mobile-exam-header { position: sticky; z-index: 30; top: 0; padding: 12px 16px 10px; border-bottom: 1px solid var(--border); background: rgba(255,255,255,.96); }
.mobile-exam-header .exam-topbar { margin-bottom: 9px; }
.mobile-exam-header .timer { font-size: 21px; }
.mobile-exam-body { padding: 18px 14px 34px; }
.mobile-exam .question-card { box-shadow: none; }
.mobile-exam-actions { position: fixed; z-index: 35; inset: auto 0 0; display: grid; grid-template-columns: 1fr auto 1fr; gap: 8px; padding: 10px 14px calc(10px + env(safe-area-inset-bottom)); border-top: 1px solid var(--border); background: rgba(255,255,255,.97); }
.mobile-exam-actions .button:last-child { justify-self: stretch; }

.bottom-sheet-backdrop { position: fixed; z-index: 80; inset: 0; display: flex; align-items: flex-end; background: rgba(15,23,42,.45); }
.bottom-sheet { width: 100%; max-height: 82vh; overflow: auto; padding: 20px 18px calc(24px + env(safe-area-inset-bottom)); border-radius: 24px 24px 0 0; background: #fff; box-shadow: 0 -20px 50px rgba(15,23,42,.18); }
.bottom-sheet-header { display: flex; align-items: center; justify-content: space-between; }
.bottom-sheet .navigator-grid { grid-template-columns: repeat(10, 1fr); }
.hidden { display: none !important; }

/* Results, review and statistics */
.result-hero { padding: clamp(28px, 5vw, 48px); text-align: center; }
.result-hero.pass { border-color: #9bd6ab; background: linear-gradient(145deg, #fff, #eefbf2); }
.result-hero.fail { border-color: #efb2b2; background: linear-gradient(145deg, #fff, #fff1f2); }
.result-state { color: var(--success); font-size: 14px; font-weight: 900; letter-spacing: .16em; text-transform: uppercase; }
.result-hero.fail .result-state { color: var(--danger); }
.score { margin: 8px 0 0; font-size: clamp(58px, 8vw, 92px); font-weight: 900; letter-spacing: -.07em; line-height: 1; }
.score small { color: var(--muted); font-size: .34em; letter-spacing: 0; }
.result-actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; margin-top: 24px; }
.result-layout { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(260px, .6fr); gap: 22px; margin-top: 22px; }
.result-metrics { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.metric-card { padding: 18px; text-align: center; }
.metric-card strong { display: block; font-size: 30px; }
.metric-card span { color: var(--muted); font-size: 12px; }
.performance-list { display: grid; gap: 13px; }
.performance-row { display: grid; grid-template-columns: minmax(120px, 1fr) minmax(100px, 2fr) auto; align-items: center; gap: 12px; }
.performance-bar { background: #e5eeed; }
.toast { position: fixed; z-index: 200; right: 18px; bottom: 90px; max-width: 420px; box-shadow: var(--shadow-lg); }
.review-list { display: grid; gap: 18px; }
.review-card { padding: clamp(20px, 3vw, 30px); }
.review-answer { display: flex; gap: 10px; margin: 8px 0; padding: 10px 12px; border-radius: 10px; background: var(--background); }
.review-answer.correct { color: #166534; background: var(--success-soft); }
.review-answer.incorrect { color: #991b1b; background: var(--danger-soft); }
.empty-state { padding: 42px 26px; text-align: center; }

.footer-disclaimer { max-width: 920px; margin-top: 36px; color: var(--muted); font-size: 12px; }

/* Complete answer key */
.answer-key-header { max-width: 940px; }
.answer-key-totals { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 22px; }
.answer-key-totals span { min-height: 42px; display: inline-flex; align-items: center; gap: 6px; padding: 8px 13px; border: 1px solid #bfe2dd; border-radius: 999px; color: var(--primary-dark); background: var(--primary-soft); font-size: 13px; }
.answer-key-totals strong { font-size: 17px; }
.answer-key-layout { display: grid; grid-template-columns: minmax(230px, 280px) minmax(0, 1fr); gap: 24px; align-items: start; }
.answer-key-sidebar { position: sticky; top: 24px; padding: 22px; }
.answer-key-controls { display: grid; gap: 16px; }
.answer-key-controls input,
.answer-key-controls select { width: 100%; min-height: 48px; padding: 10px 12px; border: 1px solid var(--border-strong); border-radius: 11px; color: var(--text); background: #fff; }
.answer-key-match-count { margin: 0; color: var(--muted); font-size: 13px; }
.answer-key-match-count strong { color: var(--text); font-size: 18px; }
.answer-key-control-actions { display: grid; gap: 6px; }
.answer-key-sidebar-nav { display: grid; gap: 8px; margin-top: 22px; padding-top: 18px; border-top: 1px solid var(--border); }
.answer-key-sidebar-nav a { min-height: 52px; display: grid; grid-template-columns: 38px minmax(0, 1fr); align-items: center; gap: 8px; padding: 8px 10px; border-radius: 10px; color: var(--text); text-decoration: none; }
.answer-key-sidebar-nav a:hover { color: var(--primary-dark); background: var(--primary-soft); }
.answer-key-sidebar-nav strong { font-size: 20px; }
.answer-key-sidebar-nav span { color: var(--muted); font-size: 13px; }
.answer-key-section { scroll-margin-top: 24px; }
.answer-key-section + .answer-key-section { margin-top: 48px; }
.answer-key-section .section-heading { align-items: center; margin-top: 0; }
.answer-key-section .section-heading .eyebrow { margin-bottom: 5px; }
.answer-key-question-list { display: grid; gap: 12px; }
.answer-key-question { overflow: clip; }
.answer-key-question summary { min-height: 78px; display: grid; grid-template-columns: 42px minmax(0, 1fr) 28px; align-items: center; gap: 14px; padding: 16px 18px; cursor: pointer; list-style: none; }
.answer-key-question summary::-webkit-details-marker { display: none; }
.answer-key-question[open] summary { border-bottom: 1px solid var(--border); background: #fbfefd; }
.answer-key-number { width: 38px; height: 38px; display: grid; place-items: center; border-radius: 11px; color: var(--primary-dark); background: var(--primary-soft); font-size: 13px; font-weight: 850; }
.answer-key-summary-copy { min-width: 0; display: grid; gap: 8px; }
.answer-key-summary-copy > strong { line-height: 1.35; }
.answer-key-badges { display: flex; flex-wrap: wrap; gap: 6px; }
.answer-key-toggle { position: relative; width: 28px; height: 28px; border-radius: 50%; background: var(--background-strong); }
.answer-key-toggle::before,
.answer-key-toggle::after { content: ""; position: absolute; top: 13px; left: 8px; width: 12px; height: 2px; border-radius: 2px; background: var(--primary-dark); }
.answer-key-toggle::after { transform: rotate(90deg); transition: transform .15s ease; }
.answer-key-question[open] .answer-key-toggle::after { transform: rotate(0); }
.answer-key-question-body { padding: 20px 22px 24px 74px; }
.answer-key-thai { margin-bottom: 14px; color: var(--muted); }
.answer-key-choices { display: grid; gap: 8px; }
.answer-key-choice { min-height: 50px; display: grid; grid-template-columns: 34px minmax(0, 1fr) auto; align-items: center; gap: 10px; padding: 9px 12px; border: 1px solid var(--border); border-radius: 11px; background: var(--background); }
.answer-key-choice > span:nth-child(2) { min-width: 0; display: grid; gap: 2px; }
.answer-key-choice small { color: var(--muted); font-size: 12px; }
.answer-key-choice.correct { border-color: #86d39b; background: var(--success-soft); }
.answer-key-choice.correct .answer-marker { color: #fff; border-color: var(--success); background: var(--success); }
.correct-label { color: #166534; font-size: 12px; font-weight: 800; }
.answer-key-explanation { margin-top: 18px; padding: 16px; border-left: 4px solid var(--primary); border-radius: 0 10px 10px 0; background: var(--primary-soft); }
.answer-key-explanation p { margin: 5px 0 0; }
.answer-key-question-body .source-line { margin-bottom: 0; }
.answer-key-sign-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
.answer-key-sign { min-width: 0; display: grid; grid-template-columns: 148px minmax(0, 1fr); overflow: hidden; }
.answer-key-sign-visual { min-height: 220px; display: grid; place-items: center; padding: 16px; background: linear-gradient(145deg, #fbfdfd, #edf5f4); }
.answer-key-sign-visual img { width: 100%; height: 150px; object-fit: contain; }
.answer-key-sign-copy { min-width: 0; padding: 18px; }
.answer-key-sign-copy h3 { margin: 12px 0 4px; }
.answer-key-sign-copy h3 a { text-decoration: none; }
.answer-key-sign-copy h3 a:hover { color: var(--primary-dark); text-decoration: underline; }
.answer-key-sign-copy p { margin-bottom: 12px; font-size: 14px; }
.answer-key-sign-copy .answer-key-thai { font-size: 13px; }
.answer-key-sign-copy .driver-action { margin-bottom: 0; padding-top: 10px; border-top: 1px solid var(--border); }
.answer-key-jumps { display: none; }
.answer-key-mobile-tools { display: none; }
.answer-key-empty { margin-top: 20px; }
.answer-key-item[hidden],
.answer-key-section[hidden],
.answer-key-empty[hidden] { display: none !important; }

/* Traffic-sign library and practice */
.sign-home-feature { display: flex; align-items: center; justify-content: space-between; gap: 24px; margin-top: 22px; padding: clamp(22px, 4vw, 34px); border-color: #b8ddd8; background: linear-gradient(120deg, #fff, #effaf8); }
.sign-home-feature h2 { margin-bottom: 8px; }
.sign-home-feature p:not(.eyebrow) { max-width: 680px; margin-bottom: 0; color: #465a58; }
.sign-home-feature .hero-actions { flex: 0 0 auto; margin-top: 0; }
.sign-home-feature .button-primary,
.sign-detail .button-primary,
.statistics-signs .button-primary { color: #fff; background: var(--primary); }
.sign-home-feature .button-secondary,
.sign-detail .button-secondary,
.statistics-signs .button-secondary { color: var(--text); border-color: var(--border); background: #fff; }
.sign-library-header { display: flex; flex-direction: column; align-items: flex-start; }
.sign-filter-panel { display: grid; grid-template-columns: minmax(200px, 1.5fr) minmax(180px, 1fr) minmax(190px, 1fr) auto; align-items: end; gap: 14px; padding: 18px; }
.sign-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(178px, 1fr)); gap: 14px; }
.sign-card { min-width: 0; overflow: hidden; color: inherit; text-decoration: none; transition: transform .16s ease, border-color .16s ease, box-shadow .16s ease; }
.sign-card:hover { transform: translateY(-3px); border-color: #8bc8c1; box-shadow: var(--shadow-lg); }
.sign-card-image { position: relative; min-height: 168px; display: grid; place-items: center; padding: 18px; background: linear-gradient(145deg, #fbfdfd, #edf5f4); }
.sign-card-image img { width: 100%; height: 138px; object-fit: contain; }
.sign-card-copy { min-width: 0; display: grid; gap: 5px; padding: 15px; }
.sign-card-copy strong { line-height: 1.25; }
.sign-code { width: fit-content; display: inline-flex; min-height: 24px; align-items: center; padding: 3px 8px; border-radius: 999px; color: var(--primary-dark); background: var(--primary-soft); font-size: 12px; font-weight: 850; }
.pagination { display: flex; align-items: center; justify-content: center; gap: 18px; margin-top: 24px; }
.pagination .disabled { pointer-events: none; opacity: .45; }
.back-link { min-height: 44px; display: inline-flex; align-items: center; margin-bottom: 18px; color: var(--primary-dark); font-weight: 750; text-decoration: none; }
.sign-detail { display: grid; grid-template-columns: minmax(280px, .75fr) minmax(0, 1.25fr); overflow: hidden; }
.sign-detail-visual { min-height: 520px; display: grid; place-items: center; align-content: center; gap: 22px; padding: clamp(28px, 5vw, 52px); background: linear-gradient(145deg, #fafffe, #e9f4f2); }
.sign-detail-visual img { width: 100%; max-width: 380px; max-height: 400px; object-fit: contain; }
.sign-detail-copy { padding: clamp(26px, 5vw, 52px); }
.thai-name { color: var(--muted); font-size: 22px; }
.source-panel { margin-top: 26px; padding-top: 20px; border-top: 1px solid var(--border); }
.source-panel h2 { font-size: 19px; }
.source-panel p { color: var(--muted); font-size: 13px; }
.source-panel a { color: var(--primary-dark); font-weight: 700; }
.sign-setup-layout { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(280px, .85fr); gap: 22px; align-items: start; }
.sign-session-form { display: grid; gap: 20px; }
.sign-session-form fieldset { margin: 0; padding: 0; border: 0; }
.sign-session-form legend { margin-bottom: 8px; color: #425553; font-size: 13px; font-weight: 700; }
.choice-chips { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; }
.choice-chips label { cursor: pointer; }
.choice-chips input { position: absolute; opacity: 0; pointer-events: none; }
.choice-chips span { min-height: 48px; display: grid; place-items: center; padding: 8px; border: 1px solid var(--border-strong); border-radius: 11px; background: #fff; font-size: 13px; font-weight: 750; text-align: center; }
.choice-chips input:checked + span { color: #fff; border-color: var(--primary); background: var(--primary); }
.choice-chips input:focus-visible + span { outline: 2px solid var(--info); outline-offset: 3px; }
.sign-session-topbar { position: sticky; z-index: 24; top: 0; display: flex; align-items: center; justify-content: space-between; gap: 12px; margin: -18px 0 18px; padding: 12px 16px; border: 1px solid var(--border); border-radius: 0 0 14px 14px; background: rgba(255,255,255,.96); box-shadow: var(--shadow); backdrop-filter: blur(14px); }
.sign-session-topbar span { color: var(--muted); font-size: 13px; }
.sign-practice-layout { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 22px; align-items: start; }
.sign-question-workspace { min-width: 0; display: grid; gap: 18px; }
.sign-question-card { padding: clamp(20px, 3vw, 34px); }
.sign-question-card h1 { margin: 22px 0 18px; font-size: clamp(23px, 3vw, 32px); text-align: center; }
.practice-sign-image { min-height: 260px; display: grid; place-items: center; padding: 18px; border-radius: 16px; background: linear-gradient(145deg, #fbfdfd, #eaf4f2); }
.practice-sign-image img { width: 100%; height: 300px; object-fit: contain; }
.sign-answer-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
.sign-answer { min-height: 64px; display: grid; grid-template-columns: 36px minmax(0, 1fr); align-items: center; gap: 12px; padding: 11px 14px; border: 1px solid var(--border); border-radius: 13px; color: var(--text); background: #fff; cursor: pointer; text-align: left; }
.sign-answer > span { width: 34px; height: 34px; display: grid; place-items: center; border: 1px solid var(--border-strong); border-radius: 9px; color: var(--primary-dark); font-weight: 850; }
.sign-answer:hover { border-color: var(--primary); background: #fbfefd; }
.sign-answer.selected { border-color: var(--primary); background: var(--primary-soft); }
.sign-answer.correct { border-color: #86d39b; background: var(--success-soft); }
.sign-answer.incorrect { border-color: #f2aaaa; background: var(--danger-soft); }
.sign-answer.correct > span { color: #fff; border-color: var(--success); background: var(--success); }
.sign-answer.incorrect > span { color: #fff; border-color: var(--danger); background: var(--danger); }
.sign-feedback { padding: 22px; border-left: 5px solid var(--success); }
.sign-feedback.incorrect-feedback { border-left-color: var(--danger); }
.sign-session-status { position: sticky; top: 20px; max-height: calc(100vh - 40px); overflow: auto; padding: 20px; }
.sign-session-status .sign-feedback { margin: 18px 0 0; padding: 16px; box-shadow: none; }
.sign-status-heading { display: flex; align-items: flex-start; justify-content: space-between; gap: 8px; }
.sign-status-heading h2 { font-size: 21px; }
.sign-session-status progress { width: 100%; height: 8px; accent-color: var(--primary); }
.sign-navigator { display: grid; grid-template-columns: repeat(5, 1fr); gap: 7px; max-height: 280px; margin: 18px 0; overflow: auto; }
.sign-session-actions { position: sticky; z-index: 25; bottom: 0; display: grid; grid-template-columns: 1fr auto 1fr; gap: 10px; margin-top: 18px; padding: 10px; border: 1px solid var(--border); border-radius: 14px 14px 0 0; background: rgba(255,255,255,.96); box-shadow: 0 -8px 24px rgba(15,23,42,.08); }
.sign-session-actions .button:last-child { justify-self: stretch; }
.mobile-sign-nav-button, .mobile-sign-nav-close { display: none; }
.compact-sign-grid { grid-template-columns: repeat(auto-fill, minmax(160px, 220px)); justify-content: center; }
.mistake-type-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.mistake-type-card { padding: clamp(22px, 4vw, 34px); }
.mistake-type-card .hero-actions .button-primary { color: #fff; background: var(--primary); }
.mistake-type-card .hero-actions .button-secondary { color: var(--text); border-color: var(--border); background: #fff; }
.mistake-type-icon { width: 46px; height: 46px; display: grid; place-items: center; margin-bottom: 18px; border-radius: 13px; color: var(--primary-dark); background: var(--primary-soft); font-weight: 900; }
.sign-mistake-type { border-color: #aad7d1; }
.statistics-signs { margin-top: 42px; }
.statistics-signs > .panel { margin-top: 16px; }
.image-error-card { max-width: 260px; padding: 14px; border: 1px dashed #e6b56a; border-radius: 10px; color: #744a08; background: #fffaf0; font-size: 12px; text-align: center; }

@media (min-width: 1200px) {
    .desktop-only { display: block; }
}

@media (min-width: 768px) and (max-width: 1199px) {
    .tablet-header .brand-copy span { display: none; }
    .tablet-home-grid { grid-template-columns: 1fr 1fr; }
    .category-grid { grid-template-columns: repeat(2, 1fr); }
    .stats-stack { grid-template-columns: repeat(2, 1fr); }
    .practice-layout { grid-template-columns: minmax(210px, .75fr) minmax(0, 1.75fr); }
    .filter-grid { grid-template-columns: repeat(2, 1fr); }
    .tablet-exam-layout { grid-template-columns: minmax(0, 1.9fr) minmax(250px, 1fr); }
    .tablet-exam-layout .exam-context { position: sticky; top: 90px; max-height: calc(100vh - 112px); overflow: auto; }
    .result-layout { grid-template-columns: 1fr; }
    .answer-key-sign-list { grid-template-columns: 1fr; }
    .tablet-home-grid .sign-home-feature { align-items: flex-start; flex-direction: column; }
    .sign-filter-panel { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .sign-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .sign-card-image { min-height: 156px; }
    .sign-detail { grid-template-columns: 1fr; }
    .sign-detail-visual { min-height: 360px; }
    .sign-practice-layout { grid-template-columns: minmax(0, 1.9fr) minmax(260px, 1fr); }
    .sign-session-status { position: sticky; top: 90px; max-height: calc(100vh - 112px); }
    .sign-answer-list { grid-template-columns: 1fr; }
}

@media (max-width: 767px) {
    body { background: var(--background); }
    h1 { font-size: 34px; }
    .brand-copy span { display: none; }
    .hero-panel { padding: 28px 22px; }
    .hero-actions { display: grid; }
    .home-grid, .practice-layout, .result-layout { grid-template-columns: 1fr; }
    .category-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .category-card { min-height: 108px; padding: 15px; }
    .category-card span { display: none; }
    .stats-stack { grid-template-columns: 1fr 1fr; }
    .metric-grid, .result-metrics { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .result-metrics .metric-card:last-child { grid-column: 1 / -1; }
    .question-card { padding: 20px 16px; }
    .question-meta { align-items: flex-start; }
    .question-number { width: 100%; margin-left: 0; }
    .question-text { font-size: 21px; }
    .answer-option { min-height: 60px; }
    .question-actions { align-items: stretch; flex-direction: column; }
    .performance-row { grid-template-columns: 1fr auto; }
    .performance-bar { grid-column: 1 / -1; grid-row: 2; }
    .result-actions { display: grid; }
    .bottom-sheet .navigator-grid { grid-template-columns: repeat(5, 1fr); }
    .answer-key-header .lead { font-size: 16px; }
    .answer-key-totals { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .answer-key-totals span { justify-content: center; border-radius: 12px; text-align: center; }
    .answer-key-jumps { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; margin-bottom: 12px; }
    .answer-key-mobile-tools { display: block; padding: 16px; }
    .answer-key-controls-mobile { gap: 12px; }
    .answer-key-control-actions { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
    .answer-key-control-actions .button { min-width: 0; padding-inline: 8px; font-size: 13px; }
    .answer-key-section + .answer-key-section { margin-top: 38px; }
    .answer-key-section .section-heading { align-items: flex-start; }
    .answer-key-section .section-heading h2 { font-size: 23px; }
    .answer-key-question summary { min-height: 72px; grid-template-columns: 34px minmax(0, 1fr) 26px; gap: 10px; padding: 14px 12px; }
    .answer-key-number { width: 32px; height: 32px; }
    .answer-key-summary-copy > strong { font-size: 14px; }
    .answer-key-question-body { padding: 16px 12px 18px; }
    .answer-key-choice { grid-template-columns: 34px minmax(0, 1fr); }
    .answer-key-choice .correct-label { grid-column: 2; }
    .answer-key-sign-list { grid-template-columns: 1fr; }
    .answer-key-sign { grid-template-columns: 112px minmax(0, 1fr); }
    .answer-key-sign-visual { min-height: 180px; padding: 10px; }
    .answer-key-sign-visual img { height: 116px; }
    .answer-key-sign-copy { padding: 14px 12px; }
    .answer-key-sign-copy h3 { font-size: 17px; }
    .answer-key-sign-copy p { font-size: 13px; }
    .sign-home-feature { align-items: stretch; flex-direction: column; }
    .sign-home-feature .hero-actions { display: grid; }
    .sign-filter-panel { grid-template-columns: 1fr; }
    .sign-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
    .sign-card-image { min-height: 132px; padding: 12px; }
    .sign-card-image img { height: 112px; }
    .sign-card-copy { padding: 12px; }
    .sign-card-copy strong { font-size: 14px; }
    .pagination { justify-content: space-between; gap: 8px; }
    .pagination span { font-size: 12px; }
    .sign-detail { grid-template-columns: 1fr; }
    .sign-detail-visual { min-height: 300px; padding: 26px; }
    .sign-detail-visual img { max-height: 250px; }
    .sign-detail-copy { padding: 22px 18px; }
    .sign-setup-layout, .mistake-type-grid { grid-template-columns: 1fr; }
    .choice-chips { grid-template-columns: repeat(2, 1fr); }
    .sign-session-topbar { top: 0; margin: -22px -18px 14px; border-inline: 0; border-radius: 0; }
    .sign-practice-layout { grid-template-columns: 1fr; }
    .practice-sign-image { min-height: 220px; padding: 12px; }
    .practice-sign-image img { height: 240px; }
    .sign-question-card { padding: 18px 14px; box-shadow: none; }
    .sign-answer-list { grid-template-columns: 1fr; }
    .sign-answer { min-height: 60px; }
    .sign-session-status { position: fixed; z-index: 90; inset: auto 0 0; top: auto; max-height: 82vh; overflow: auto; padding: 22px 18px calc(24px + env(safe-area-inset-bottom)); border-radius: 24px 24px 0 0; transform: translateY(110%); transition: transform .2s ease; box-shadow: 0 -24px 60px rgba(15,23,42,.24); }
    .sign-session-status::before { content: ""; position: fixed; z-index: -1; inset: -100vh 0 100%; background: rgba(15,23,42,.4); pointer-events: none; opacity: 0; transition: opacity .2s ease; }
    .sign-session-status.open { transform: translateY(0); }
    .sign-session-status.open::before { opacity: 1; }
    .mobile-sign-nav-button, .mobile-sign-nav-close { display: inline-flex; }
    .sign-session-actions { position: fixed; z-index: 35; inset: auto 0 71px; margin: 0; padding: 9px 12px; border-inline: 0; border-radius: 0; }
    .mobile-content:has(.sign-practice-layout) { padding-bottom: 96px; }
    .compact-sign-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

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