/* ============================================================
   MFR Library — app.css
   Design language: "clinical instrument panel"
   - deep slate ground, single clinical-teal accent, signal amber for warnings
   - humanist serif for chapter titles (Lora), grotesk for UI (Inter),
     monospace for data/citations/scores (JetBrains Mono)
   - hairline rules, square-ish radii, data treated as readouts
   Scoped under .mfrl-* to avoid theme collisions.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Lora:ital,wght@0,500;0,600;1,500&family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500;700&display=swap');

:where(.mfrl-chapter, .mfrl-lib, .mfrl-quiz, .mfrl-exam, .mfrl-stats, .mfrl-source, .mfrl-paywall) {
    --mfrl-ink: #0d1b2a;          /* near-black slate, text */
    --mfrl-ground: #f6f8f9;       /* page panel */
    --mfrl-panel: #ffffff;
    --mfrl-line: #d3dde2;         /* hairline */
    --mfrl-line-strong: #9fb3bd;
    --mfrl-teal: #0e7c86;         /* clinical accent */
    --mfrl-teal-deep: #095159;
    --mfrl-teal-wash: #e4f1f2;
    --mfrl-amber: #b45309;        /* signal / warning */
    --mfrl-amber-wash: #fdf0dd;
    --mfrl-green: #15803d;
    --mfrl-green-wash: #e3f3e8;
    --mfrl-red: #b91c1c;
    --mfrl-red-wash: #fbe8e8;
    --mfrl-muted: #5b6b73;

    --mfrl-serif: 'Lora', Georgia, serif;
    --mfrl-sans: 'Inter', system-ui, sans-serif;
    --mfrl-mono: 'JetBrains Mono', ui-monospace, monospace;

    --mfrl-radius: 6px;
    --mfrl-shadow: 0 1px 2px rgba(13,27,42,.06), 0 8px 24px -16px rgba(13,27,42,.25);

    font-family: var(--mfrl-sans);
    color: var(--mfrl-ink);
    line-height: 1.6;
    box-sizing: border-box;
}
:where(.mfrl-chapter, .mfrl-lib, .mfrl-quiz, .mfrl-exam, .mfrl-stats, .mfrl-source, .mfrl-paywall) *,
:where(.mfrl-chapter, .mfrl-lib, .mfrl-quiz, .mfrl-exam, .mfrl-stats, .mfrl-source, .mfrl-paywall) *::before,
:where(.mfrl-chapter, .mfrl-lib, .mfrl-quiz, .mfrl-exam, .mfrl-stats, .mfrl-source, .mfrl-paywall) *::after {
    box-sizing: inherit;
}

/* ── Buttons ───────────────────────────────────── */
.mfrl-btn {
    font-family: var(--mfrl-sans);
    font-weight: 600;
    font-size: 14px;
    padding: 10px 18px;
    border-radius: var(--mfrl-radius);
    border: 1px solid transparent;
    cursor: pointer;
    transition: transform .08s ease, background .15s ease, box-shadow .15s ease;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    line-height: 1;
}
.mfrl-btn:active { transform: translateY(1px); }
.mfrl-btn--primary { background: var(--mfrl-teal); color: #fff; }
.mfrl-btn--primary:hover { background: var(--mfrl-teal-deep); }
.mfrl-btn--primary:disabled { background: var(--mfrl-line-strong); cursor: not-allowed; }
.mfrl-btn--ghost { background: transparent; color: var(--mfrl-teal-deep); border-color: var(--mfrl-line-strong); }
.mfrl-btn--ghost:hover { background: var(--mfrl-teal-wash); }
.mfrl-btn--lg { padding: 14px 28px; font-size: 16px; }

/* ── Chips / readouts ──────────────────────────── */
.mfrl-chip {
    font-family: var(--mfrl-mono);
    font-size: 11px;
    letter-spacing: .04em;
    text-transform: uppercase;
    padding: 4px 9px;
    border: 1px solid var(--mfrl-line-strong);
    border-radius: 3px;
    color: var(--mfrl-muted);
    background: var(--mfrl-panel);
}
.mfrl-chip[data-k="grile"] { color: var(--mfrl-teal-deep); border-color: var(--mfrl-teal); background: var(--mfrl-teal-wash); }

.mfrl-note { color: var(--mfrl-muted); font-style: italic; padding: 12px 0; }

/* ============================================================
   CHAPTER PAGE
   ============================================================ */
.mfrl-chapter { max-width: 880px; margin: 0 auto; }
.mfrl-chapter__eyebrow {
    display: flex; justify-content: space-between; align-items: baseline;
    font-family: var(--mfrl-mono); font-size: 12px; letter-spacing: .03em;
    color: var(--mfrl-muted); border-bottom: 1px solid var(--mfrl-line);
    padding-bottom: 10px; margin-bottom: 14px;
}
.mfrl-chapter__no { color: var(--mfrl-teal); font-weight: 700; }
.mfrl-chapter__title {
    font-family: var(--mfrl-serif); font-weight: 600;
    font-size: clamp(28px, 4vw, 42px); line-height: 1.12;
    margin: 0 0 14px; color: var(--mfrl-ink); letter-spacing: -.01em;
}
.mfrl-chapter__meta { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 28px; }
.mfrl-chapter section { margin: 32px 0; }
.mfrl-chapter h2 {
    font-family: var(--mfrl-sans); font-size: 13px; font-weight: 700;
    text-transform: uppercase; letter-spacing: .08em; color: var(--mfrl-teal-deep);
    border-left: 3px solid var(--mfrl-teal); padding-left: 10px; margin: 0 0 16px;
}
.mfrl-prose { font-size: 16px; }
.mfrl-keypoints { list-style: none; padding: 0; margin: 16px 0 0; display: grid; gap: 8px; }
.mfrl-keypoints li {
    position: relative; padding: 8px 12px 8px 30px; background: var(--mfrl-ground);
    border-radius: var(--mfrl-radius); font-size: 14.5px;
}
.mfrl-keypoints li::before {
    content: '▸'; position: absolute; left: 11px; top: 8px; color: var(--mfrl-teal); font-weight: 700;
}

/* ============================================================
   SOURCE VIEWER (3 modes)
   ============================================================ */
.mfrl-source {
    border: 1px solid var(--mfrl-line); border-radius: var(--mfrl-radius);
    background: var(--mfrl-panel); overflow: hidden; box-shadow: var(--mfrl-shadow);
}
.mfrl-source__bar {
    display: flex; align-items: center; gap: 12px; justify-content: space-between;
    padding: 10px 14px; background: var(--mfrl-ink); color: #cfe3e6;
    font-family: var(--mfrl-mono); font-size: 12px; letter-spacing: .03em;
}
.mfrl-source__label { text-transform: uppercase; color: #8fb6bb; }
.mfrl-source__cite, .mfrl-source__pick { font-family: var(--mfrl-mono); font-size: 12px; }
.mfrl-source__pick {
    background: #16344a; color: #e3eef0; border: 1px solid #28506a;
    border-radius: 4px; padding: 4px 8px; max-width: 60%;
}
/* pdfjs */
.mfrl-source__canvas-wrap { position: relative; background: #eef2f4; padding: 14px; text-align: center; }
.mfrl-source__canvas { max-width: 100%; height: auto; box-shadow: 0 2px 10px rgba(0,0,0,.12); background:#fff; }
.mfrl-source__nav {
    display: flex; align-items: center; justify-content: center; gap: 14px; margin-top: 10px;
    font-family: var(--mfrl-mono); font-size: 13px; color: var(--mfrl-muted);
}
.mfrl-source__nav button {
    width: 34px; height: 34px; border: 1px solid var(--mfrl-line-strong); background: #fff;
    border-radius: 4px; cursor: pointer; font-size: 18px; line-height: 1; color: var(--mfrl-teal-deep);
}
.mfrl-source__nav button:hover { background: var(--mfrl-teal-wash); }
/* pages (screenshots) */
.mfrl-source__grid { display: grid; grid-template-columns: repeat(auto-fill,minmax(220px,1fr)); gap: 14px; padding: 14px; }
.mfrl-source__shot { margin: 0; border: 1px solid var(--mfrl-line); border-radius: 5px; overflow: hidden; background: #fff; }
.mfrl-source__shot img { width: 100%; display: block; }
.mfrl-source__shot figcaption {
    font-family: var(--mfrl-mono); font-size: 11px; color: var(--mfrl-muted);
    padding: 7px 9px; border-top: 1px solid var(--mfrl-line); background: var(--mfrl-ground);
}
/* text+highlight */
.mfrl-source__excerpt { padding: 16px 18px; font-size: 15.5px; line-height: 1.7; }
.mfrl-hl { background: var(--mfrl-amber-wash); border-bottom: 2px solid var(--mfrl-amber); padding: 0 2px; }

/* ============================================================
   QUIZ
   ============================================================ */
.mfrl-quiz { border: 1px solid var(--mfrl-line); border-radius: 10px; background: var(--mfrl-panel); padding: 0; box-shadow: var(--mfrl-shadow); }
.mfrl-quiz__progress { display: flex; align-items: center; gap: 12px; padding: 14px 18px 0; }
.mfrl-quiz__bar { flex: 1; height: 5px; background: var(--mfrl-line); border-radius: 3px; overflow: hidden; position: relative; }
.mfrl-quiz__bar > span { position: absolute; inset: 0 100% 0 0; background: var(--mfrl-teal); transition: right .3s ease; }
.mfrl-quiz__counter { font-family: var(--mfrl-mono); font-size: 12px; color: var(--mfrl-muted); }
.mfrl-quiz__stage { padding: 18px; }
.mfrl-quiz__concept { font-family: var(--mfrl-mono); font-size: 11px; text-transform: uppercase; letter-spacing: .05em; color: var(--mfrl-teal); margin-bottom: 8px; }
.mfrl-quiz__q { font-size: 18px; font-weight: 600; line-height: 1.4; margin-bottom: 16px; font-family: var(--mfrl-serif); }
.mfrl-quiz__options { display: grid; gap: 9px; }
.mfrl-quiz__opt {
    text-align: left; padding: 13px 15px; border: 1px solid var(--mfrl-line); background: var(--mfrl-panel);
    border-radius: var(--mfrl-radius); cursor: pointer; font-size: 15px; font-family: var(--mfrl-sans);
    transition: border-color .12s, background .12s; display: flex; gap: 11px; align-items: flex-start; width: 100%;
}
.mfrl-quiz__opt:hover:not(:disabled) { border-color: var(--mfrl-teal); background: var(--mfrl-teal-wash); }
.mfrl-quiz__opt[aria-pressed="true"] { border-color: var(--mfrl-teal); background: var(--mfrl-teal-wash); box-shadow: inset 0 0 0 1px var(--mfrl-teal); }
.mfrl-quiz__opt[data-state="correct"] { border-color: var(--mfrl-green); background: var(--mfrl-green-wash); }
.mfrl-quiz__opt[data-state="incorrect"] { border-color: var(--mfrl-red); background: var(--mfrl-red-wash); }
.mfrl-quiz__opt:disabled { cursor: default; }
.mfrl-quiz__optkey {
    font-family: var(--mfrl-mono); font-weight: 700; font-size: 13px; color: var(--mfrl-teal-deep);
    background: var(--mfrl-panel); border: 1px solid var(--mfrl-line-strong); border-radius: 3px;
    width: 24px; height: 24px; display: inline-flex; align-items: center; justify-content: center; flex: 0 0 auto;
}
.mfrl-quiz__explanation {
    margin-top: 14px; padding: 13px 15px; border-radius: var(--mfrl-radius); font-size: 14.5px; line-height: 1.6;
    background: var(--mfrl-ground); border-left: 3px solid var(--mfrl-teal);
}
.mfrl-quiz__explanation[data-verdict="correct"] { border-left-color: var(--mfrl-green); }
.mfrl-quiz__explanation[data-verdict="incorrect"] { border-left-color: var(--mfrl-red); }
.mfrl-quiz__explanation strong { font-family: var(--mfrl-mono); font-size: 11px; text-transform: uppercase; letter-spacing: .05em; }
.mfrl-quiz__controls { display: flex; gap: 10px; padding: 0 18px 18px; }
.mfrl-quiz__done { padding: 28px 18px; text-align: center; }
.mfrl-quiz__score { font-family: var(--mfrl-mono); font-size: 46px; font-weight: 700; color: var(--mfrl-teal); }
.mfrl-quiz__scorelbl { color: var(--mfrl-muted); margin-bottom: 18px; }

/* ============================================================
   EXAM
   ============================================================ */
.mfrl-exam { border: 1px solid var(--mfrl-line); border-radius: 10px; background: var(--mfrl-panel); padding: 24px; box-shadow: var(--mfrl-shadow); }
.mfrl-exam__title { font-family: var(--mfrl-serif); font-size: 26px; margin: 0 0 6px; }
.mfrl-exam__lede { color: var(--mfrl-muted); margin: 0 0 20px; }
.mfrl-exam__row { display: flex; gap: 18px; flex-wrap: wrap; margin-bottom: 16px; }
.mfrl-exam__row label { font-size: 13px; font-weight: 600; display: flex; flex-direction: column; gap: 6px; }
.mfrl-exam__row select { font-family: var(--mfrl-mono); padding: 8px 12px; border: 1px solid var(--mfrl-line-strong); border-radius: var(--mfrl-radius); font-size: 15px; }
.mfrl-exam__scope { margin: 8px 0 20px; }
.mfrl-exam__scope summary { cursor: pointer; font-size: 14px; color: var(--mfrl-teal-deep); font-weight: 600; }
.mfrl-exam__chips { display: grid; grid-template-columns: repeat(auto-fill,minmax(220px,1fr)); gap: 6px; margin-top: 12px; }
.mfrl-checkchip { display: flex; gap: 8px; align-items: center; font-size: 13px; padding: 6px 8px; border: 1px solid var(--mfrl-line); border-radius: 4px; cursor: pointer; }
.mfrl-checkchip:hover { background: var(--mfrl-ground); }
.mfrl-exam__timer {
    position: sticky; top: 10px; float: right; font-family: var(--mfrl-mono); font-size: 20px; font-weight: 700;
    background: var(--mfrl-ink); color: #cfe3e6; padding: 8px 14px; border-radius: var(--mfrl-radius); z-index: 5;
}
.mfrl-exam__timer[data-low="1"] { background: var(--mfrl-red); color: #fff; }
.mfrl-exam__qcard { border: 1px solid var(--mfrl-line); border-radius: var(--mfrl-radius); padding: 16px; margin-bottom: 12px; }
.mfrl-exam__qnum { font-family: var(--mfrl-mono); font-size: 12px; color: var(--mfrl-muted); }
.mfrl-exam__qtext { font-weight: 600; margin: 6px 0 12px; font-size: 16px; }
.mfrl-exam__result-score { font-family: var(--mfrl-mono); font-size: 54px; font-weight: 700; }
.mfrl-exam__result-score[data-pass="1"] { color: var(--mfrl-green); }
.mfrl-exam__result-score[data-pass="0"] { color: var(--mfrl-amber); }

/* ============================================================
   STATS
   ============================================================ */
.mfrl-stats__cards { display: grid; grid-template-columns: repeat(auto-fit,minmax(160px,1fr)); gap: 14px; margin-bottom: 26px; }
.mfrl-stat { border: 1px solid var(--mfrl-line); border-radius: 10px; padding: 20px; background: var(--mfrl-panel); box-shadow: var(--mfrl-shadow); }
.mfrl-stat__num { font-family: var(--mfrl-mono); font-size: 38px; font-weight: 700; color: var(--mfrl-teal); line-height: 1; }
.mfrl-stat__lbl { color: var(--mfrl-muted); font-size: 13px; margin-top: 8px; }
.mfrl-stats h3 { font-family: var(--mfrl-sans); font-size: 13px; text-transform: uppercase; letter-spacing: .07em; color: var(--mfrl-teal-deep); margin: 0 0 12px; }
.mfrl-stats__weak ul { list-style: none; padding: 0; margin: 0 0 26px; display: grid; gap: 6px; }
.mfrl-stats__weak li { display: flex; justify-content: space-between; align-items: center; padding: 9px 13px; background: var(--mfrl-ground); border-radius: var(--mfrl-radius); }
.mfrl-weak__c { font-size: 14px; }
.mfrl-weak__a { font-family: var(--mfrl-mono); font-weight: 700; color: var(--mfrl-green); }
.mfrl-weak__a[data-low="1"] { color: var(--mfrl-red); }
.mfrl-table { width: 100%; border-collapse: collapse; font-size: 14px; }
.mfrl-table th { text-align: left; font-family: var(--mfrl-mono); font-size: 11px; text-transform: uppercase; letter-spacing: .04em; color: var(--mfrl-muted); border-bottom: 2px solid var(--mfrl-line-strong); padding: 8px 10px; }
.mfrl-table td { padding: 9px 10px; border-bottom: 1px solid var(--mfrl-line); }
.mfrl-table td:nth-child(n+2), .mfrl-table th:nth-child(n+2) { font-family: var(--mfrl-mono); text-align: right; }

/* ============================================================
   LIBRARY INDEX
   ============================================================ */
.mfrl-lib__bar { display: flex; align-items: center; gap: 14px; margin-bottom: 22px; }
.mfrl-lib__search { flex: 1; font-family: var(--mfrl-sans); font-size: 16px; padding: 13px 16px; border: 1px solid var(--mfrl-line-strong); border-radius: var(--mfrl-radius); background: var(--mfrl-panel); }
.mfrl-lib__search:focus { outline: 2px solid var(--mfrl-teal); outline-offset: 1px; border-color: var(--mfrl-teal); }
.mfrl-lib__count { font-family: var(--mfrl-mono); font-size: 12px; color: var(--mfrl-muted); white-space: nowrap; }
.mfrl-lib__section { margin-bottom: 30px; }
.mfrl-lib__sectitle { font-family: var(--mfrl-sans); font-size: 12px; font-weight: 700; text-transform: uppercase; letter-spacing: .08em; color: var(--mfrl-teal-deep); border-bottom: 1px solid var(--mfrl-line); padding-bottom: 8px; margin: 0 0 14px; display: flex; align-items: center; gap: 8px; }
.mfrl-lib__grid { display: grid; grid-template-columns: repeat(auto-fill,minmax(280px,1fr)); gap: 12px; }
.mfrl-card { display: block; text-decoration: none; color: inherit; border: 1px solid var(--mfrl-line); border-radius: 8px; padding: 16px; background: var(--mfrl-panel); transition: border-color .12s, transform .08s, box-shadow .15s; }
.mfrl-card:hover { border-color: var(--mfrl-teal); transform: translateY(-2px); box-shadow: var(--mfrl-shadow); }
.mfrl-card__no { font-family: var(--mfrl-mono); font-size: 11px; color: var(--mfrl-teal); font-weight: 700; }
.mfrl-card__title { font-family: var(--mfrl-serif); font-size: 18px; font-weight: 600; margin: 4px 0 10px; line-height: 1.25; }
.mfrl-card__meta { display: flex; gap: 6px; flex-wrap: wrap; }
.mfrl-card__concepts { margin-top: 10px; display: flex; flex-wrap: wrap; gap: 4px; }
.mfrl-card__concept { font-family: var(--mfrl-mono); font-size: 10px; color: var(--mfrl-muted); background: var(--mfrl-ground); border-radius: 3px; padding: 2px 6px; }
.mfrl-card__concept mark { background: var(--mfrl-amber-wash); }
.mfrl-lib__empty { color: var(--mfrl-muted); font-style: italic; padding: 30px; text-align: center; }

/* ============================================================
   PAYWALL
   ============================================================ */
.mfrl-paywall { max-width: 560px; margin: 30px auto; text-align: center; border: 1px solid var(--mfrl-line); border-radius: 12px; padding: 40px 28px; background: var(--mfrl-panel); box-shadow: var(--mfrl-shadow); }
.mfrl-paywall__lock { font-size: 40px; margin-bottom: 10px; }
.mfrl-paywall__title { font-family: var(--mfrl-serif); font-size: 26px; margin: 0 0 12px; }
.mfrl-paywall__lede { color: var(--mfrl-muted); font-size: 15px; margin: 0 0 22px; }
.mfrl-paywall__cta { display: flex; gap: 10px; justify-content: center; margin-top: 18px; }

/* ── Responsive ────────────────────────────────── */
@media (max-width: 640px) {
    .mfrl-quiz__q { font-size: 17px; }
    .mfrl-source__pick { max-width: 50%; }
    .mfrl-exam__timer { font-size: 17px; padding: 6px 10px; }
}
/* ── Reduced motion ────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
    .mfrl-btn, .mfrl-card, .mfrl-quiz__bar > span { transition: none; }
}

/* ── Difficulty selector ── */
.mfrl-quiz__diff{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:14px}
.mfrl-quiz__diff-label{font-size:13px;color:#64748b;font-weight:600}
.mfrl-diff-btn{border:1px solid #cbd5e1;background:#fff;color:#334155;border-radius:999px;padding:5px 14px;font-size:13px;cursor:pointer;transition:all .15s;font-family:inherit}
.mfrl-diff-btn:hover{border-color:#0e7c86;color:#0e7c86}
.mfrl-diff-btn.is-active{background:#0e7c86;border-color:#0e7c86;color:#fff}