.btcf-tcf-quiz {
    --btcf-red:#b51f2e;
    --btcf-red-dark:#8f1722;
    --btcf-red-soft:#fff3f4;
    --btcf-text:#20242c;
    --btcf-muted:#667085;
    --btcf-border:#e4e7ec;
    --btcf-bg:#f7f8fa;
    max-width:980px;
    margin:24px auto;
}
.btcf-tcf-quiz .qsm-quiz-form { position:relative; }
.btcf-exam-header {
    position:sticky; top:0; z-index:30;
    background:rgba(255,255,255,.97);
    border:1px solid var(--btcf-border);
    border-radius:14px;
    padding:16px 20px 13px;
    margin:0 0 24px;
    box-shadow:0 6px 20px rgba(16,24,40,.06);
    backdrop-filter:blur(8px);
}
.btcf-header-top { display:flex; align-items:center; justify-content:space-between; gap:18px; }
.btcf-section-title { color:var(--btcf-red); font-weight:800; font-size:13px; text-transform:uppercase; letter-spacing:.4px; }
.btcf-question-count { color:var(--btcf-text); font-weight:700; font-size:14px; margin-top:4px; }
.btcf-timer { min-width:92px; display:flex; align-items:center; justify-content:center; gap:7px; padding:9px 12px; background:var(--btcf-bg); border-radius:9px; color:var(--btcf-text); }
.btcf-timer strong { font-size:17px; }
.btcf-time-warning .btcf-timer, .btcf-time-over .btcf-timer { background:#fff0f1; color:#b4232d; }
.btcf-progress { height:6px; border-radius:999px; overflow:hidden; background:#edf0f3; margin-top:13px; }
.btcf-progress span { display:block; height:100%; width:0; border-radius:999px; background:var(--btcf-red); transition:width .25s ease; }
.btcf-tcf-quiz .btcf-question { background:#fff; border:1px solid var(--btcf-border); border-radius:16px; padding:28px !important; }
.btcf-tcf-quiz .mlw_qmn_new_question { color:var(--btcf-text); font-size:22px; line-height:1.45; font-weight:700; margin-bottom:8px; }
.btcf-tcf-quiz .mlw_qmn_question { color:var(--btcf-text); font-size:16px; line-height:1.7; }
.btcf-tcf-quiz .qmn_radio_answers { display:flex !important; flex-direction:column; gap:10px; margin-top:20px; }
.btcf-tcf-quiz .qmn_mc_answer_wrap { position:relative; margin:0 !important; border:1.5px solid var(--btcf-border); border-radius:11px; background:#fff; transition:.18s ease; }
.btcf-tcf-quiz .qmn_mc_answer_wrap:hover { border-color:var(--btcf-red); background:#fffafb; }
.btcf-tcf-quiz .qmn_quiz_radio { position:absolute; opacity:0; pointer-events:none; }
.btcf-tcf-quiz .qsm-input-label { width:100%; display:flex !important; align-items:center; gap:13px; padding:14px 16px !important; cursor:pointer; color:var(--btcf-text); }
.btcf-answer-letter { width:32px; height:32px; flex:0 0 32px; border-radius:50%; display:inline-flex; align-items:center; justify-content:center; background:var(--btcf-bg); color:#475467; font-size:12px; font-weight:800; }
.btcf-tcf-quiz .qmn_mc_answer_wrap:has(.qmn_quiz_radio:checked) { border-color:var(--btcf-red); background:var(--btcf-red-soft); }
.btcf-tcf-quiz .qmn_mc_answer_wrap:has(.qmn_quiz_radio:checked) .btcf-answer-letter { background:var(--btcf-red); color:#fff; }
.btcf-audio-box { display:flex; align-items:center; gap:16px; padding:18px; margin:0 0 24px; background:var(--btcf-bg); border:1px solid #eceff2; border-radius:13px; }
.btcf-audio-icon { width:52px; height:52px; flex:0 0 52px; display:flex; align-items:center; justify-content:center; border-radius:50%; background:#fff; font-size:22px; box-shadow:0 3px 12px rgba(0,0,0,.05); }
.btcf-audio-main strong { display:block; color:var(--btcf-text); font-size:16px; }
.btcf-audio-main p { color:var(--btcf-muted); font-size:13px; margin:4px 0 10px; }
.btcf-audio-play { border:0; border-radius:8px; padding:10px 16px; background:var(--btcf-red); color:#fff; font-weight:700; cursor:pointer; }
.btcf-audio-play:hover { background:var(--btcf-red-dark); }
.btcf-audio-play:disabled { background:#a8afb8; cursor:not-allowed; }
.btcf-audio-status { color:#16833d; font-size:12px; margin-top:8px; }
.btcf-reading-grid { display:grid; grid-template-columns:minmax(0,1fr) minmax(0,1fr); gap:26px; }
.btcf-reading-passage { background:var(--btcf-bg); border:1px solid var(--btcf-border); border-radius:12px; padding:20px; align-self:start; max-height:560px; overflow:auto; }
.btcf-passage-label { color:var(--btcf-red); font-size:11px; letter-spacing:.7px; font-weight:800; margin-bottom:12px; }
.btcf-passage-text { color:#344054; line-height:1.75; }
.btcf-tcf-quiz .qsm-btn, .btcf-tcf-quiz .qmn_btn { border-radius:8px !important; padding:11px 20px !important; font-weight:700 !important; }
.btcf-tcf-quiz .qsm-next, .btcf-tcf-quiz .mlw_next { background:var(--btcf-red) !important; border-color:var(--btcf-red) !important; color:#fff !important; }
.btcf-tcf-quiz .mlw_previous, .btcf-tcf-quiz .qsm-previous { background:#fff !important; color:var(--btcf-red) !important; border:1px solid var(--btcf-red) !important; }
@media (max-width:767px){
    .btcf-tcf-quiz { margin:12px auto; }
    .btcf-exam-header { border-radius:10px; padding:13px 14px 11px; }
    .btcf-tcf-quiz .btcf-question { padding:20px 16px !important; border-radius:12px; }
    .btcf-tcf-quiz .mlw_qmn_new_question { font-size:19px; }
    .btcf-reading-grid { grid-template-columns:1fr; gap:16px; }
    .btcf-reading-passage { max-height:none; }
    .btcf-audio-box { align-items:flex-start; padding:15px; }
    .btcf-audio-icon { width:42px; height:42px; flex-basis:42px; font-size:18px; }
}

/* ===== v0.2.1: Start screen + section transitions ===== */
.btcf-tcf-quiz.btcf-prestart .qsm-quiz-form,
.btcf-tcf-quiz.btcf-prestart .qmn_pagination { display:none !important; }
.btcf-start-screen {
    background:#fff;
    border:1px solid var(--btcf-border);
    border-radius:18px;
    padding:36px;
    box-shadow:0 12px 40px rgba(16,24,40,.08);
    text-align:center;
}
.btcf-start-badge {
    display:inline-flex;
    padding:6px 12px;
    border-radius:999px;
    background:var(--btcf-red-soft);
    color:var(--btcf-red);
    font-size:12px;
    font-weight:800;
    letter-spacing:.6px;
    margin-bottom:14px;
}
.btcf-start-screen h2 { margin:0; color:var(--btcf-text); font-size:32px; line-height:1.25; }
.btcf-start-sub { color:var(--btcf-muted); font-size:16px; margin:8px 0 26px; }
.btcf-start-sections { display:grid; grid-template-columns:repeat(3,minmax(0,1fr)); gap:12px; margin:0 0 18px; text-align:left; }
.btcf-start-section { display:flex; align-items:center; gap:12px; border:1px solid var(--btcf-border); border-radius:12px; padding:16px; background:#fff; }
.btcf-start-icon { width:40px; height:40px; flex:0 0 40px; display:flex; align-items:center; justify-content:center; border-radius:10px; background:var(--btcf-bg); font-size:19px; }
.btcf-start-section-copy { display:flex; flex-direction:column; min-width:0; }
.btcf-start-section-copy strong { color:var(--btcf-text); font-size:14px; }
.btcf-start-section-copy small { color:var(--btcf-muted); margin-top:3px; font-size:12px; }
.btcf-start-summary { display:flex; justify-content:center; gap:18px; color:#344054; font-size:14px; margin:14px 0; }
.btcf-start-note { max-width:760px; margin:18px auto; padding:13px 15px; border-radius:10px; background:#fff8e8; color:#665116; text-align:left; line-height:1.55; font-size:13px; }
.btcf-audio-test-hint {
    max-width:760px;
    margin:14px auto 2px;
    display:flex;
    align-items:center;
    justify-content:center;
    gap:8px;
    color:#475467;
    font-size:13px;
    font-weight:700;
    line-height:1.45;
}
.btcf-audio-test-hint-icon { width:18px; height:18px; flex:0 0 18px; color:var(--btcf-aqua, #1597d4); }
.btcf-start-actions { display:flex; justify-content:center; flex-wrap:wrap; gap:10px; margin-top:20px; }
.btcf-audio-test,
.btcf-start-btn,
.btcf-transition-continue { border-radius:9px; padding:12px 18px; font-weight:800; cursor:pointer; font-size:14px; }
.btcf-audio-test { border:1px solid var(--btcf-border); background:#fff; color:#344054; }
.btcf-audio-test:hover { border-color:var(--btcf-red); color:var(--btcf-red); }
.btcf-start-btn,
.btcf-transition-continue { border:1px solid var(--btcf-red); background:var(--btcf-red); color:#fff; }
.btcf-start-btn:hover,
.btcf-transition-continue:hover { background:var(--btcf-red-dark); border-color:var(--btcf-red-dark); }
.btcf-audio-test-status { min-height:18px; margin-top:10px; color:#16833d; font-size:12px; }
.btcf-transition[hidden] { display:none !important; }
.btcf-transition {
    position:fixed;
    inset:0;
    z-index:99999;
    display:flex;
    align-items:center;
    justify-content:center;
    padding:20px;
    background:rgba(17,24,39,.55);
    backdrop-filter:blur(4px);
}
.btcf-transition-card {
    width:min(520px,100%);
    background:#fff;
    border-radius:18px;
    padding:30px;
    text-align:center;
    box-shadow:0 24px 70px rgba(0,0,0,.22);
}
.btcf-transition-icon {
    width:62px;
    height:62px;
    margin:0 auto 14px;
    border-radius:50%;
    background:var(--btcf-red-soft);
    color:var(--btcf-red);
    display:flex;
    align-items:center;
    justify-content:center;
    font-size:27px;
    font-weight:800;
}
.btcf-transition-kicker { color:var(--btcf-red); font-size:11px; font-weight:800; letter-spacing:.8px; }
.btcf-transition-card h3 { margin:8px 0; color:var(--btcf-text); font-size:24px; }
.btcf-transition-copy { margin:4px 0; color:#344054; font-size:16px; font-weight:700; }
.btcf-transition-meta { margin:8px 0 18px; color:var(--btcf-muted); font-size:13px; }
.btcf-transition-auto { min-height:18px; margin-top:10px; color:var(--btcf-muted); font-size:12px; }
.btcf-tcf-quiz .qsm-progress-bar,
.btcf-tcf-quiz .pages_count { display:none !important; }
.btcf-tcf-quiz .quiz_begin { /* QSM begin page is replaced by BTCF start screen after click */ }

@media (max-width:767px){
    .btcf-start-screen { padding:24px 16px; border-radius:13px; }
    .btcf-start-screen h2 { font-size:25px; }
    .btcf-start-sections { grid-template-columns:1fr; }
    .btcf-start-summary { flex-direction:column; gap:4px; }
    .btcf-start-actions { flex-direction:column; }
    .btcf-audio-test, .btcf-start-btn { width:100%; }
    .btcf-transition-card { padding:24px 18px; border-radius:14px; }
    .btcf-transition-card h3 { font-size:21px; }
}


/* ===== v0.3.1: TCF Simulation deferred feedback ===== */
/* QSM must never reveal correctness while the candidate is still taking the exam. */
.btcf-tcf-quiz.btcf-feedback-deferred .quick-question-res-p,
.btcf-tcf-quiz.btcf-feedback-deferred .qsm-inline-correct-info,
.btcf-tcf-quiz.btcf-feedback-deferred .qsm-correct-answer-info,
.btcf-tcf-quiz.btcf-feedback-deferred .qsm-incorrect-answer-info {
    display:none !important;
}
/* Neutralize QSM correct/incorrect classes if an older quiz had ajax_show_correct enabled. */
.btcf-tcf-quiz.btcf-feedback-deferred .qmn_correct_answer,
.btcf-tcf-quiz.btcf-feedback-deferred .qmn_incorrect_answer,
.btcf-tcf-quiz.btcf-feedback-deferred .data-correct-answer {
    color:inherit !important;
    background:inherit !important;
    border-color:inherit !important;
    box-shadow:none !important;
}
/* The only visible state during the exam is the candidate's current selection. */
.btcf-tcf-quiz.btcf-feedback-deferred .qmn_mc_answer_wrap:has(.qmn_quiz_radio:checked) {
    border-color:var(--btcf-aqua, #1597d4) !important;
    background:var(--btcf-aqua-soft, #eef9fe) !important;
}
.btcf-tcf-quiz.btcf-feedback-deferred .qmn_mc_answer_wrap:has(.qmn_quiz_radio:checked) .btcf-answer-letter {
    background:var(--btcf-aqua, #1597d4) !important;
    color:#fff !important;
}

/* ===== v0.5.0: candidate info, stable viewport, aqua selection, scored result ===== */
.btcf-tcf-quiz {
    --btcf-aqua:#1597d4;
    --btcf-aqua-dark:#087fb8;
    --btcf-aqua-soft:#eef9fe;
}

/* Giữ chiều cao vùng làm bài ổn định để footer không nhảy lên/xuống giữa các câu ngắn. */
.btcf-tcf-quiz:not(.btcf-prestart) .qsm-auto-page-row,
.btcf-tcf-quiz:not(.btcf-prestart) .qsm-page {
    min-height:clamp(520px, calc(100vh - 265px), 760px);
}

/* Trạng thái được chọn: xanh nước. Đỏ vẫn dành cho nhận diện thương hiệu/nút điều hướng. */
.btcf-tcf-quiz .qmn_mc_answer_wrap:has(.qmn_quiz_radio:checked),
.btcf-tcf-quiz.btcf-feedback-deferred .qmn_mc_answer_wrap:has(.qmn_quiz_radio:checked) {
    border-color:var(--btcf-aqua) !important;
    background:var(--btcf-aqua-soft) !important;
    box-shadow:0 0 0 1px rgba(21,151,212,.08) !important;
}
.btcf-tcf-quiz .qmn_mc_answer_wrap:has(.qmn_quiz_radio:checked) .btcf-answer-letter,
.btcf-tcf-quiz.btcf-feedback-deferred .qmn_mc_answer_wrap:has(.qmn_quiz_radio:checked) .btcf-answer-letter {
    background:var(--btcf-aqua) !important;
    color:#fff !important;
}

.btcf-candidate-card {
    max-width:820px;
    margin:22px auto 16px;
    padding:20px;
    border:1px solid var(--btcf-border);
    border-radius:14px;
    background:#fbfcfd;
    text-align:left;
}
.btcf-candidate-heading { display:flex; flex-direction:column; gap:3px; margin-bottom:15px; }
.btcf-candidate-heading strong { color:var(--btcf-text); font-size:16px; }
.btcf-candidate-heading span { color:var(--btcf-muted); font-size:12px; }
.btcf-candidate-grid { display:grid; grid-template-columns:1.2fr .85fr 1.2fr; gap:12px; }
.btcf-candidate-grid label { display:flex; flex-direction:column; gap:6px; }
.btcf-candidate-grid label > span { color:#344054; font-size:12px; font-weight:700; }
.btcf-candidate-grid em { color:var(--btcf-red); font-style:normal; }
.btcf-candidate-grid input {
    width:100%; min-height:44px; box-sizing:border-box;
    padding:10px 12px; border:1px solid #d8dee7; border-radius:9px;
    background:#fff; color:var(--btcf-text); font-size:14px; outline:none;
    transition:border-color .15s ease, box-shadow .15s ease;
}
.btcf-candidate-grid input:focus { border-color:var(--btcf-aqua); box-shadow:0 0 0 3px rgba(21,151,212,.12); }
.btcf-candidate-error { min-height:18px; margin-top:9px; color:#b42318; font-size:12px; font-weight:600; }
.btcf-start-btn:disabled { opacity:.65; cursor:wait; }

.btcf-result-screen {
    --btcf-red:#b51f2e; --btcf-aqua:#1597d4; --btcf-text:#20242c; --btcf-muted:#667085; --btcf-border:#e4e7ec;
    max-width:980px; margin:28px auto; padding:34px;
    background:#fff; border:1px solid var(--btcf-border); border-radius:20px;
    box-shadow:0 14px 48px rgba(16,24,40,.09);
}
.btcf-result-kicker { color:var(--btcf-red); font-size:12px; font-weight:900; letter-spacing:.8px; margin-bottom:14px; }
.btcf-result-hero { display:grid; grid-template-columns:190px 1fr; gap:28px; align-items:center; padding:24px; background:#f8fafc; border-radius:16px; }
.btcf-result-level {
    width:160px; height:160px; border-radius:50%; margin:auto;
    display:flex; flex-direction:column; justify-content:center; align-items:center;
    background:#fff; border:8px solid #e8f6fc; box-shadow:inset 0 0 0 2px var(--btcf-aqua);
}
.btcf-result-level small { color:var(--btcf-muted); font-size:11px; text-align:center; }
.btcf-result-level strong { color:var(--btcf-aqua); font-size:50px; line-height:1; margin-top:5px; }
.btcf-result-summary h2 { margin:0 0 8px; color:var(--btcf-text); font-size:28px; }
.btcf-result-summary p { margin:0; color:#475467; line-height:1.65; }
.btcf-result-meta { display:flex; gap:14px; flex-wrap:wrap; margin-top:18px; }
.btcf-result-meta span { padding:8px 12px; border-radius:999px; background:#fff; border:1px solid var(--btcf-border); color:#475467; font-size:13px; }
.btcf-result-meta b { color:var(--btcf-text); }
.btcf-result-sections { display:grid; grid-template-columns:repeat(3,minmax(0,1fr)); gap:14px; margin:22px 0; }
.btcf-result-section { padding:18px; border:1px solid var(--btcf-border); border-radius:14px; }
.btcf-result-section-head { display:flex; justify-content:space-between; gap:8px; align-items:flex-start; min-height:42px; }
.btcf-result-section-head strong { color:#344054; font-size:13px; line-height:1.35; }
.btcf-result-section-head span { flex:0 0 auto; padding:4px 8px; border-radius:999px; background:var(--btcf-aqua-soft,#eef9fe); color:var(--btcf-aqua); font-size:11px; font-weight:900; }
.btcf-result-section-score { display:flex; justify-content:space-between; gap:10px; align-items:flex-end; margin:12px 0 8px; }
.btcf-result-section-score b { color:var(--btcf-text); font-size:22px; }
.btcf-result-section-score small { color:var(--btcf-muted); text-align:right; line-height:1.35; }
.btcf-result-bar { height:7px; border-radius:999px; background:#edf2f5; overflow:hidden; }
.btcf-result-bar span { display:block; height:100%; border-radius:inherit; background:var(--btcf-aqua); }
.btcf-result-contact { display:flex; flex-wrap:wrap; gap:10px 20px; padding:15px 18px; background:#fafafa; border-radius:12px; color:#475467; font-size:12px; }
.btcf-result-note { margin-top:16px; padding:14px 16px; border-radius:11px; background:#fff8e8; color:#665116; font-size:12px; line-height:1.6; }
.btcf-result-reload { margin-top:20px; border:1px solid var(--btcf-red); background:var(--btcf-red); color:#fff; border-radius:9px; padding:11px 18px; font-weight:800; cursor:pointer; }
.btcf-result-reload:hover { background:#8f1722; }

@media (max-width:767px){
    .btcf-tcf-quiz:not(.btcf-prestart) .qsm-auto-page-row,
    .btcf-tcf-quiz:not(.btcf-prestart) .qsm-page { min-height:460px; }
    .btcf-candidate-grid { grid-template-columns:1fr; }
    .btcf-result-screen { margin:14px auto; padding:20px 14px; border-radius:14px; }
    .btcf-result-hero { grid-template-columns:1fr; padding:18px 14px; text-align:center; }
    .btcf-result-summary h2 { font-size:23px; }
    .btcf-result-meta { justify-content:center; }
    .btcf-result-sections { grid-template-columns:1fr; }
    .btcf-result-contact { flex-direction:column; gap:7px; }
}
.btcf-tcf-quiz .qmn_mc_answer_wrap:hover {
    border-color:var(--btcf-aqua) !important;
    background:#f8fdff !important;
}
.btcf-result-loading { max-width:980px; margin:30px auto; padding:36px; text-align:center; color:#475467; font-weight:700; background:#fff; border:1px solid #e4e7ec; border-radius:16px; }

/* v0.5.1 result transport/finalization states */
.btcf-finalize-error{max-width:760px;margin:18px auto;padding:18px 20px;border:1px solid #f0b6b6;border-radius:14px;background:#fff7f7;color:#7a271a;box-shadow:0 8px 24px rgba(16,24,40,.06)}
.btcf-finalize-error strong{display:block;font-size:17px;margin-bottom:5px}
.btcf-finalize-error p{margin:0 0 12px;line-height:1.55}
.btcf-finalize-error button,.btcf-result-error .btcf-result-retry{border:0;border-radius:10px;padding:11px 18px;background:#1796d2;color:#fff;font-weight:700;cursor:pointer}
.btcf-finalize-error button:hover,.btcf-result-error .btcf-result-retry:hover{filter:brightness(.96)}
.btcf-result-error{max-width:760px;margin:32px auto;text-align:center;padding:42px 32px}
.btcf-result-error h2{margin:8px 0 10px;color:#101828}
.btcf-result-error p{max-width:600px;margin:0 auto 20px;color:#475467;line-height:1.65}

/* ===== v0.6.0: release hardening / server resume ===== */
.btcf-resume-note {
    max-width:820px;
    margin:12px auto 4px;
    padding:10px 14px;
    border:1px solid #b9e2f5;
    border-radius:10px;
    background:#f2fbff;
    color:#087fb8;
    font-size:13px;
    font-weight:700;
    text-align:center;
}

/* ===== v0.6.8: listening split layout + clean icons + question navigation ===== */
.btcf-icon-svg {
    width:22px;
    height:22px;
    display:block;
}
.btcf-button-icon {
    width:18px;
    height:18px;
    display:block;
    flex:0 0 18px;
}
.btcf-start-icon {
    color:var(--btcf-aqua, #1597d4);
}
.btcf-start-actions .btcf-audio-test,
.btcf-start-actions .btcf-start-btn {
    display:inline-flex;
    align-items:center;
    justify-content:center;
    gap:8px;
}

/* Listening: media/prompt on the left, answer choices on the right. */
.btcf-tcf-quiz .btcf-question.btcf-listening-ready {
    padding:24px !important;
}
.btcf-listening-grid {
    display:grid;
    grid-template-columns:minmax(280px,.82fr) minmax(360px,1.18fr);
    gap:24px;
    align-items:start;
}
.btcf-listening-left,
.btcf-listening-right {
    min-width:0;
}
.btcf-listening-left {
    display:flex;
    flex-direction:column;
    gap:16px;
    padding:20px;
    border:1px solid #e6ebf0;
    border-radius:14px;
    background:#f8fafc;
}
.btcf-listening-left .btcf-audio-box {
    margin:0;
    background:#fff;
}
.btcf-listening-left .mlw_qmn_new_question,
.btcf-listening-left .mlw_qmn_question {
    margin:0;
}
.btcf-listening-left img {
    max-width:100%;
    height:auto;
    border-radius:10px;
}
.btcf-listening-right {
    padding:4px 0 0;
}
.btcf-listening-answer-label {
    margin:0 0 10px;
    color:var(--btcf-muted);
    font-size:11px;
    font-weight:800;
    letter-spacing:.65px;
}
.btcf-listening-right .qmn_radio_answers {
    margin-top:0 !important;
}
.btcf-listening-ready .btcf-audio-icon {
    color:var(--btcf-aqua, #1597d4);
}

@media (max-width: 820px) {
    .btcf-listening-grid {
        grid-template-columns:1fr;
        gap:16px;
    }
    .btcf-listening-left {
        padding:16px;
    }
    .btcf-listening-right {
        padding-top:0;
    }
}