/* on-luyen.css – Trang Ôn luyện GPLX */

/* ===== RESET & BASE ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
    --ol-blue:    #1565C0;
    --ol-blue-d:  #0D47A1;
    --ol-blue-l:  #1E88E5;
    --ol-blue-p:  #E3F2FD;
    --ol-green:   #388E3C;
    --ol-green-l: #4CAF50;
    --ol-green-p: #E8F5E9;
    --ol-red:     #C62828;
    --ol-red-l:   #EF5350;
    --ol-red-p:   #FFEBEE;
    --ol-yellow:  #FFD600;
    --ol-orange:  #EF6C00;
    --ol-gray:    #F5F5F5;
    --ol-gray2:   #E0E0E0;
    --ol-gray3:   #BDBDBD;
    --ol-text:    #212121;
    --ol-text2:   #37474F;
    --ol-text3:   #78909C;
    --ol-font:    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Helvetica, Arial, sans-serif;
}
html { font-size: 16px; }
body {
    font-family: var(--ol-font);
    background: #f0f2f5;
    color: var(--ol-text);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== HEADER ===== */
.ol-header {
    background: var(--ol-blue);
    color: #fff;
    padding: 12px 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 4px rgba(0,0,0,.2);
}
.ol-back-btn {
    background: none;
    border: none;
    color: #fff;
    font-size: 20px;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 4px;
    text-decoration: none;
    display: flex;
    align-items: center;
}
.ol-back-btn:hover { background: rgba(255,255,255,.15); }
.ol-title {
    font-size: 18px;
    font-weight: 500;
    flex: 1;
}
.ol-hang-badge {
    background: rgba(255,255,255,.2);
    border: 1px solid rgba(255,255,255,.4);
    border-radius: 4px;
    padding: 2px 10px;
    font-size: 14px;
    font-weight: 600;
}

/* ===== LICENSE SELECTOR (in practice screen) ===== */
.ol-hang-bar {
    background: #fff;
    padding: 8px 16px;
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    border-bottom: 2px solid var(--ol-gray2);
}
.ol-hang-chip {
    border: 1.5px solid var(--ol-gray3);
    border-radius: 16px;
    padding: 4px 14px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    background: #fff;
    color: var(--ol-text2);
    transition: all .15s;
}
.ol-hang-chip:hover { border-color: var(--ol-blue); color: var(--ol-blue); }
.ol-hang-chip.active {
    background: var(--ol-blue);
    border-color: var(--ol-blue);
    color: #fff;
}

/* ===== MAIN CONTENT ===== */
.ol-main {
    flex: 1;
    max-width: 1100px;
    width: 100%;
    margin: 0 auto;
    padding: 16px;
}

/* ===== MODE TABS ===== */
.ol-mode-tabs {
    display: flex;
    gap: 0;
    background: #fff;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 1px 3px rgba(0,0,0,.1);
    margin-bottom: 16px;
}
.ol-mode-tab {
    flex: 1;
    padding: 10px 12px;
    text-align: center;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    border: none;
    background: none;
    color: var(--ol-text3);
    border-bottom: 3px solid transparent;
    transition: all .15s;
}
.ol-mode-tab:hover { color: var(--ol-blue); }
.ol-mode-tab.active {
    color: var(--ol-blue);
    border-bottom-color: var(--ol-blue);
    font-weight: 600;
}

/* ===== MENU SECTIONS ===== */
.ol-section {
    display: none;
}
.ol-section.active { display: block; }

.ol-card {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0,0,0,.1);
    overflow: hidden;
    margin-bottom: 16px;
}
.ol-card-header {
    padding: 14px 16px;
    font-size: 15px;
    font-weight: 600;
    color: var(--ol-blue);
    border-bottom: 1px solid var(--ol-gray2);
    display: flex;
    align-items: center;
    gap: 8px;
}
.ol-card-header .icon { font-size: 18px; }
.ol-card-body { padding: 12px; }

/* ===== FIXED EXAM SETS (2-column grid) ===== */
.ol-de-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    gap: 8px;
}
.ol-de-btn {
    border: 1.5px solid var(--ol-gray2);
    border-radius: 6px;
    padding: 8px 4px;
    text-align: center;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    background: #fff;
    color: var(--ol-text2);
    transition: all .15s;
}
.ol-de-btn:hover {
    border-color: var(--ol-blue);
    color: var(--ol-blue);
    background: var(--ol-blue-p);
}
.ol-de-btn:active {
    background: var(--ol-blue);
    color: #fff;
}

/* ===== PRACTICE TYPE BUTTONS ===== */
.ol-menu-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 12px;
}
.ol-menu-item {
    border: 1.5px solid var(--ol-gray2);
    border-radius: 8px;
    padding: 16px;
    cursor: pointer;
    background: #fff;
    text-align: left;
    transition: all .2s;
    display: flex;
    align-items: flex-start;
    gap: 12px;
}
.ol-menu-item:hover {
    border-color: var(--ol-blue);
    background: var(--ol-blue-p);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(21,101,192,.15);
}
.ol-menu-icon {
    width: 40px;
    height: 40px;
    border-radius: 8px;
    background: var(--ol-blue-p);
    color: var(--ol-blue);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    flex-shrink: 0;
}
.ol-menu-item:hover .ol-menu-icon {
    background: var(--ol-blue);
    color: #fff;
}
.ol-menu-text h3 {
    font-size: 14px;
    font-weight: 600;
    color: var(--ol-text);
    margin-bottom: 4px;
}
.ol-menu-text p {
    font-size: 12px;
    color: var(--ol-text3);
    line-height: 1.4;
}

/* Critical item gets special red accent */
.ol-menu-item.critical { border-color: #FFCDD2; }
.ol-menu-item.critical:hover { border-color: var(--ol-red); background: var(--ol-red-p); }
.ol-menu-item.critical .ol-menu-icon { background: #FFCDD2; color: var(--ol-red); }
.ol-menu-item.critical:hover .ol-menu-icon { background: var(--ol-red); color: #fff; }

/* ===== PROGRESS BAR CHO BẢNG THÀNH TÍCH ÔN LUYỆN ===== */
.ol-progress-card {
    margin-top: 12px;
    padding: 12px;
    background: linear-gradient(135deg,#F8FAFC,#F1F5F9);
    border: 1px solid #E2E8F0;
    border-radius: 10px;
}
.ol-progress-card .ol-progress-head {
    display: flex; align-items: center; justify-content: space-between;
    font-size: 12px; color: var(--ol-text3); margin-bottom: 6px;
}
.ol-progress-card .ol-progress-head strong { color: var(--ol-blue); font-size: 13px; }
.ol-progress-bar {
    width: 100%;
    height: 10px;
    background: #E2E8F0;
    border-radius: 999px;
    overflow: hidden;
    box-shadow: inset 0 1px 2px rgba(0,0,0,0.06);
}
.ol-progress-bar > span {
    display: block;
    height: 100%;
    background: linear-gradient(90deg, var(--ol-blue-l), var(--ol-blue));
    transition: width .35s ease;
    border-radius: 999px;
}
.ol-progress-bar.full > span { background: linear-gradient(90deg,#22C55E,#16A34A); }
.ol-progress-bar.partial > span { background: linear-gradient(90deg,#F59E0B,#D97706); }
.ol-progress-stats {
    display: grid;
    grid-template-columns: repeat(3, minmax(0,1fr));
    gap: 8px;
    margin-top: 10px;
    font-size: 11.5px;
    color: var(--ol-text3);
}
.ol-progress-stats .lbl { font-size: 10.5px; opacity: .85; text-transform: uppercase; letter-spacing: .3px; margin-bottom: 2px; }
.ol-progress-stats .val { font-size: 14px; font-weight: 800; color: var(--ol-text); }
.ol-progress-stats .val.green { color: #15803D; }
.ol-progress-stats .val.red   { color: #B91C1C; }

/* ===== CHAPTER GRID ===== */
.ol-chapter-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 12px;
}
.ol-chapter-btn {
    border: 1.5px solid var(--ol-gray2);
    border-radius: 8px;
    padding: 14px;
    cursor: pointer;
    background: #fff;
    text-align: left;
    transition: all .15s;
    display: flex;
    align-items: center;
    gap: 12px;
}
.ol-chapter-btn:hover {
    border-color: var(--ol-blue);
    background: var(--ol-blue-p);
}
.ol-chapter-num {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--ol-blue);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 700;
    flex-shrink: 0;
}
.ol-chapter-btn:hover .ol-chapter-num { background: var(--ol-blue-d); }
.ol-chapter-info h4 {
    font-size: 13px;
    font-weight: 600;
    color: var(--ol-text);
    margin-bottom: 2px;
}
.ol-chapter-info p {
    font-size: 12px;
    color: var(--ol-text3);
}

/* ===== RANGE GRID ===== */
.ol-range-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 8px;
}
.ol-range-btn {
    border: 1.5px solid var(--ol-gray2);
    border-radius: 6px;
    padding: 10px 8px;
    text-align: center;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    background: #fff;
    color: var(--ol-text2);
    transition: all .15s;
}
.ol-range-btn:hover { border-color: var(--ol-blue); color: var(--ol-blue); background: var(--ol-blue-p); }

/* Custom range input */
.ol-custom-range {
    display: flex;
    gap: 8px;
    align-items: center;
    padding: 8px 0;
    flex-wrap: wrap;
}
.ol-custom-range input[type=number] {
    width: 80px;
    padding: 8px;
    border: 1.5px solid var(--ol-gray3);
    border-radius: 6px;
    font-size: 14px;
    text-align: center;
}
.ol-custom-range input:focus { outline: none; border-color: var(--ol-blue); }
.ol-custom-range span { color: var(--ol-text3); font-size: 14px; }
.ol-custom-go {
    padding: 8px 20px;
    background: var(--ol-blue);
    color: #fff;
    border: none;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
}
.ol-custom-go:hover { background: var(--ol-blue-d); }

/* ===== PRACTICE SCREEN (question view) ===== */
.ol-practice-screen {
    display: none;
    position: fixed;
    inset: 0;
    background: #f0f2f5;
    z-index: 200;
    flex-direction: column;
}
.ol-practice-screen.active { display: flex; }

/* Practice header */
.ol-prac-header {
    background: var(--ol-blue);
    color: #fff;
    padding: 10px 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    position: sticky;
    top: 0;
    z-index: 10;
    box-shadow: 0 2px 4px rgba(0,0,0,.2);
}
.ol-prac-title-bar {
    flex: 1;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 15px;
    font-weight: 500;
}
.ol-prac-progress {
    font-size: 13px;
    opacity: .85;
    white-space: nowrap;
}
.ol-prac-close {
    background: rgba(255,255,255,.2);
    border: none;
    color: #fff;
    font-size: 16px;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
}
.ol-prac-close:hover { background: rgba(255,255,255,.35); }

/* Practice body: question + answer + explanation */
.ol-prac-body {
    flex: 1;
    overflow-y: auto;
    padding: 16px;
    max-width: 820px;
    width: 100%;
    margin: 0 auto;
}

/* Question card */
.ol-q-card {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0,0,0,.1);
    overflow: hidden;
    margin-bottom: 12px;
}
.ol-q-header {
    padding: 10px 14px;
    display: flex;
    align-items: center;
    gap: 8px;
    border-bottom: 1px solid var(--ol-gray2);
    font-size: 13px;
    color: var(--ol-text3);
}
.ol-q-num {
    font-weight: 700;
    color: var(--ol-blue);
}
.ol-q-critical-badge {
    background: var(--ol-red);
    color: #fff;
    font-size: 11px;
    font-weight: 700;
    padding: 1px 6px;
    border-radius: 3px;
    letter-spacing: .5px;
}
.ol-q-chapter-tag {
    margin-left: auto;
    font-size: 12px;
    background: var(--ol-gray);
    padding: 1px 8px;
    border-radius: 3px;
}
.ol-q-content {
    padding: 14px;
    font-size: 15px;
    line-height: 1.6;
    color: var(--ol-text);
}
.ol-q-image {
    display: block;
    max-width: 100%;
    max-height: 300px;
    margin: 8px auto;
    border-radius: 4px;
    border: 1px solid var(--ol-gray2);
}

/* Options */
.ol-options { padding: 0 14px 14px; }
.ol-opt {
    border: 2px solid var(--ol-gray2);
    border-radius: 6px;
    padding: 10px 12px;
    margin-bottom: 8px;
    cursor: pointer;
    display: flex;
    align-items: flex-start;
    gap: 10px;
    transition: all .15s;
    font-size: 14px;
    line-height: 1.5;
}
.ol-opt:hover { border-color: var(--ol-blue); background: var(--ol-blue-p); }
.ol-opt.selected { border-color: var(--ol-blue); background: var(--ol-blue-p); }
.ol-opt.correct { border-color: var(--ol-green); background: var(--ol-green-p); }
.ol-opt.wrong { border-color: var(--ol-red); background: var(--ol-red-p); }
.ol-opt.disabled { cursor: default; pointer-events: none; }
.ol-opt-num {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    border: 1.5px solid var(--ol-gray3);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: 700;
    flex-shrink: 0;
    color: var(--ol-text3);
    background: #fff;
}
.ol-opt.selected .ol-opt-num { border-color: var(--ol-blue); color: var(--ol-blue); background: var(--ol-blue-p); }
.ol-opt.correct .ol-opt-num { border-color: var(--ol-green); color: var(--ol-green); background: var(--ol-green); color: #fff; }
.ol-opt.wrong .ol-opt-num { border-color: var(--ol-red); color: var(--ol-red); background: var(--ol-red); color: #fff; }

/* Explanation */
.ol-explanation {
    background: #FFF8E1;
    border: 1px solid #FFE082;
    border-radius: 6px;
    padding: 12px 14px;
    margin: 0 14px 14px;
    font-size: 13.5px;
    line-height: 1.6;
    color: #5D4037;
}
.ol-explanation::before {
    content: '💡 Giải thích: ';
    font-weight: 700;
    color: var(--ol-orange);
}
.ol-explanation.no-expl::before {
    content: '✓ Đáp án đúng.';
    font-weight: 700;
    color: var(--ol-green);
}

/* Practice nav footer */
.ol-prac-footer {
    position: fixed;
    left: 0; right: 0; bottom: 0;
    z-index: 100;
    background: #fff;
    border-top: 1px solid var(--ol-gray2);
    padding: 10px 12px 0;
    padding-bottom: calc(12px + env(safe-area-inset-bottom, 0px) + var(--nav-extra, 52px));
    display: flex;
    align-items: center;
    gap: 8px;
    box-shadow: 0 -6px 20px rgba(0,0,0,.12);
    flex-shrink: 0;
    max-height: none;
    overflow: visible;
}
.ol-prac-nav-btn {
    padding: 8px 18px;
    border: 1.5px solid var(--ol-gray3);
    border-radius: 6px;
    background: #fff;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    color: var(--ol-text2);
    transition: all .15s;
}
.ol-prac-nav-btn:hover { border-color: var(--ol-blue); color: var(--ol-blue); }
.ol-prac-nav-btn:disabled { opacity: .4; cursor: default; }
.ol-prac-nav-btn.primary {
    background: var(--ol-blue);
    border-color: var(--ol-blue);
    color: #fff;
}
.ol-prac-nav-btn.primary:hover { background: var(--ol-blue-d); }
.ol-prac-answers {
    flex: 1;
    display: flex;
    gap: 4px;
    flex-wrap: nowrap;
    overflow-x: auto;
    overflow-y: hidden;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    max-height: 34px;
    align-items: center;
}
.ol-prac-answers::-webkit-scrollbar { display: none; }
.ol-prac-qdot {
    flex: 0 0 auto;
    width: 26px;
    height: 26px;
    border-radius: 4px;
    border: 1.5px solid var(--ol-gray3);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 600;
    cursor: pointer;
    background: #fff;
    color: var(--ol-text3);
    transition: all .1s;
}
.ol-prac-qdot:hover { border-color: var(--ol-blue); color: var(--ol-blue); }
.ol-prac-qdot.current { border-color: var(--ol-blue); background: var(--ol-blue); color: #fff; }
.ol-prac-qdot.answered { border-color: var(--ol-green); background: var(--ol-green-p); color: var(--ol-green); }
.ol-prac-qdot.correct-dot { border-color: var(--ol-green); background: var(--ol-green); color: #fff; }
.ol-prac-qdot.wrong-dot { border-color: var(--ol-red); background: var(--ol-red); color: #fff; }

/* Result bar */
.ol-result-bar {
    background: var(--ol-green-p);
    border: 1px solid var(--ol-green);
    border-radius: 6px;
    padding: 8px 14px;
    margin: 0 14px 14px;
    font-size: 14px;
    font-weight: 600;
    color: var(--ol-green);
    text-align: center;
}
.ol-result-bar.fail { background: var(--ol-red-p); border-color: var(--ol-red); color: var(--ol-red); }

/* ===== LOADING ===== */
.ol-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 60px 20px;
    color: var(--ol-text3);
}
.ol-loading-spinner {
    width: 36px;
    height: 36px;
    border: 3px solid var(--ol-gray2);
    border-top-color: var(--ol-blue);
    border-radius: 50%;
    animation: ol-spin .8s linear infinite;
    margin-bottom: 12px;
}
@keyframes ol-spin { to { transform: rotate(360deg); } }

/* ===== RESPONSIVE ===== */
@media (max-width: 600px) {
    .ol-menu-grid { grid-template-columns: 1fr; }
    .ol-chapter-grid { grid-template-columns: 1fr; }
    .ol-de-grid { grid-template-columns: repeat(auto-fill, minmax(60px, 1fr)); }
    .ol-prac-qdot { width: 22px; height: 22px; font-size: 10px; }
    .ol-prac-answers { gap: 2px; max-height: 30px; }
}

/* Mobile tối ưu thiết bị thật */
@media (max-width: 480px) {
    html { font-size: 15px; }

    /* Header compact */
    .ol-header { padding: 10px 12px; padding-top: calc(10px + env(safe-area-inset-top, 0px)); }
    .ol-title { font-size: 15px; }
    .ol-hang-badge { width: 36px; height: 36px; font-size: 12px; }

    /* Hang bar scroll ngang */
    .ol-hang-bar { padding: 8px 12px; gap: 6px; overflow-x: auto; }
    .ol-hang-chip { padding: 6px 12px; font-size: 12px; min-height: 32px; }

    /* Main padding */
    .ol-main { padding: 12px; }
    .ol-card { margin-bottom: 12px; }
    .ol-card-body { padding: 12px; }

    /* Menu items lớn hơn */
    .ol-menu-item { padding: 12px; min-height: 64px; }
    .ol-menu-icon { width: 40px; height: 40px; font-size: 22px; }
    .ol-menu-text h3 { font-size: 14px; }
    .ol-menu-text p { font-size: 12px; }

    /* Chapter cards */
    .ol-chapter-btn { padding: 12px; min-height: 64px; }
    .ol-chapter-num { width: 36px; height: 36px; font-size: 14px; }

    /* Range buttons */
    .ol-range-btn { padding: 10px; min-height: 44px; font-size: 13px; }
    .ol-custom-range { flex-wrap: wrap; gap: 8px; }
    .ol-custom-range input { width: 70px; padding: 10px; font-size: 14px; }

    /* Practice screen */
    .ol-prac-header { padding: 8px 10px; padding-top: calc(8px + env(safe-area-inset-top, 0px)); }
    .ol-prac-close { width: 36px; height: 36px; font-size: 16px; }
    .ol-prac-title-bar { font-size: 14px; }
    .ol-prac-progress { font-size: 11px; }

    .ol-q-card { margin: 8px; padding: 12px; }
    .ol-q-content { font-size: 14px; line-height: 1.5; }
    .ol-q-image { max-height: 220px; margin: 10px 0; }
    .ol-opt {
        padding: 14px 12px;
        margin-bottom: 8px;
        font-size: 14px;
        min-height: 52px; /* vùng chạm lớn hơn cho ngón tay */
        border-radius: 8px;
    }
    .ol-opt-num { width: 28px; height: 28px; font-size: 13px; font-weight: 700; }

    /* Badge điểm liệt nổi bật trên mobile */
    .ol-q-critical-badge {
        display: inline-block;
        background: #fef2f2;
        color: #dc2626;
        border: 1px solid #fecaca;
        font-size: 11px;
        font-weight: 700;
        padding: 3px 8px;
        border-radius: 4px;
        margin-left: 6px;
        letter-spacing: 0.3px;
    }

    /* Practice footer */
    .ol-prac-footer {
        position: fixed !important;
        left: 0; right: 0; bottom: 0;
        padding: 10px 8px 0;
        gap: 6px;
        padding-bottom: calc(16px + env(safe-area-inset-bottom, 0px) + var(--nav-extra, 52px));
        background: #fff;
        border-top: 1px solid var(--ol-gray2);
        flex-shrink: 0;
        max-height: none;
        overflow: visible;
        z-index: 100;
        box-shadow: 0 -6px 20px rgba(0,0,0,.14);
    }
    .ol-prac-body, .ol-practice-screen .ol-prac-body {
        padding-bottom: calc(80px + env(safe-area-inset-bottom, 0px) + var(--nav-extra, 52px)) !important;
    }
    .ol-prac-nav-btn { padding: 10px; min-height: 44px; font-size: 13px; }

    /* Mode tabs */
    .ol-mode-tabs { padding: 8px 12px; }
    .ol-mode-tab { padding: 8px 12px; min-height: 36px; font-size: 13px; }

    /* Wrong card */
    .ol-wrong-count { font-size: 11px !important; padding: 2px 8px !important; }
}

/* Safe area cho iPhone notch */
@supports (padding: max(0px)) {
    .ol-header {
        padding-top: max(10px, env(safe-area-inset-top));
    }
    .ol-prac-footer {
        padding-bottom: max(16px, calc(12px + env(safe-area-inset-bottom, 0px)));
    }
}

/* Touch target & feedback */
.ol-opt, .ol-menu-item, .ol-range-btn, .ol-chapter-btn,
.ol-hang-chip, .ol-prac-nav-btn, .ol-mode-tab, .ol-de-btn,
.ol-prac-qdot, .ol-prac-close, #btnWrongQuestions, .ol-btn-text,
#btnResetWrong, #btnCritical, #btnRandomExam {
    touch-action: manipulation;
    -webkit-tap-highlight-color: rgba(21, 101, 192, 0.15);
}

.ol-opt:active, .ol-menu-item:active, .ol-range-btn:active,
.ol-chapter-btn:active, .ol-prac-qdot:active {
    opacity: 0.85;
}

/* Landscape: header ngang gọn */
@media (max-width: 900px) and (orientation: landscape) {
    .ol-header { padding: 6px 12px; }
    .ol-card { padding: 8px; }
    .ol-card-body { padding: 10px; }
}