:root{
    --green:#07C160;
    --green-dark:#059c4d;
    --green-light:#e6f9ee;
    --ink:#16181c;
    --ink-soft:#5b6470;
    --bg:#f5f7f8;
    --card:#ffffff;
    --line:#e8ecef;
    --danger:#e5484d;
    --amber:#d98a1f;
    --radius:16px;
    --radius-sm:10px;
    --shadow:0 2px 8px rgba(20,30,40,.06), 0 1px 2px rgba(20,30,40,.04);
    --shadow-lg:0 20px 50px rgba(15,25,35,.18);
    font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  }
  *{box-sizing:border-box;margin:0;padding:0;}
  html{-webkit-text-size-adjust:100%;}
  body{background:var(--bg);color:var(--ink);line-height:1.5;-webkit-font-smoothing:antialiased;overflow-x:hidden;}
  img{max-width:100%;display:block;}
  a{color:inherit;text-decoration:none;}
  button{font:inherit;cursor:pointer;border:none;background:none;color:inherit;}
  ul{list-style:none;}
  .wrap{max-width:1120px;margin:0 auto;padding:0 24px;}

  /* ---------- Preview banner ---------- */
  .preview-banner{background:#1a1a1a;color:#fff;font-size:.82rem;text-align:center;padding:9px 16px;position:relative;}
  .preview-banner b{color:#ffd166;}
  .preview-banner button{position:absolute;right:14px;top:50%;transform:translateY(-50%);color:#fff;opacity:.6;font-size:1rem;}
  .preview-banner button:hover{opacity:1;}
  .preview-banner.hidden{display:none;}

  /* ---------- Navbar ---------- */
  .navbar{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.9);backdrop-filter:blur(10px);border-bottom:1px solid var(--line);}
  .navbar .wrap{display:flex;align-items:center;justify-content:space-between;height:66px;}
  .brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:1.08rem;}
  .brand .logo-mark{width:34px;height:34px;border-radius:10px;background:linear-gradient(135deg,var(--green),var(--green-dark));display:flex;align-items:center;justify-content:center;color:#fff;font-size:1.1rem;flex-shrink:0;}
  .brand small{display:block;font-weight:500;font-size:.68rem;color:var(--ink-soft);}
  .nav-links{display:flex;align-items:center;gap:4px;}
  .nav-links a{padding:9px 14px;border-radius:9px;font-size:.88rem;font-weight:600;color:var(--ink-soft);text-decoration:none;}
  .nav-links a:hover{background:var(--bg);color:var(--ink);}
  .nav-links a.active{background:var(--green-light);color:var(--green-dark);}
  .nav-right{display:flex;align-items:center;gap:10px;}
  .admin-toggle{font-size:.76rem;color:var(--ink-soft);display:flex;align-items:center;gap:6px;padding:6px 10px;border-radius:20px;border:1px solid var(--line);}
  .admin-toggle input{accent-color:var(--green);}
  .logout-link{color:var(--danger);font-weight:700;font-size:.78rem;margin-left:2px;}
  .alert{padding:12px 15px;border-radius:10px;font-size:.85rem;margin-bottom:16px;}
  .alert-error{background:#fdeceb;color:var(--danger);}
  .alert-success{background:var(--green-light);color:var(--green-dark);}
  .alert-info{background:#eaf1ff;color:#2a5cc7;}

  .btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:11px 20px;border-radius:11px;font-weight:700;font-size:.9rem;transition:.15s;white-space:nowrap;}
  .btn-primary{background:var(--green);color:#fff;}
  .btn-primary:hover{background:var(--green-dark);}
  .btn-ghost{background:var(--bg);color:var(--ink);border:1px solid var(--line);}
  .btn-ghost:hover{background:#eef1f3;}
  .btn-outline{background:#fff;color:var(--green-dark);border:1.5px solid var(--green);}
  .btn-outline:hover{background:var(--green-light);}
  .btn-danger{background:#fdeceb;color:var(--danger);}
  .btn-danger:hover{background:var(--danger);color:#fff;}
  .btn-sm{padding:7px 12px;font-size:.78rem;border-radius:8px;}
  .btn-block{width:100%;}
  .btn:disabled{opacity:.5;cursor:not-allowed;}

  .user-chip{display:flex;align-items:center;gap:8px;padding:6px 12px 6px 6px;border-radius:30px;background:var(--bg);border:1px solid var(--line);font-size:.82rem;font-weight:600;}
  .avatar{width:28px;height:28px;border-radius:50%;background:linear-gradient(135deg,#6d8bff,#a06dff);color:#fff;display:flex;align-items:center;justify-content:center;font-size:.75rem;font-weight:800;}

  /* ---------- Views ---------- */
  .view{display:none;animation:fadeIn .25s ease;}
  .view.active{display:block;}
  @keyframes fadeIn{from{opacity:0;transform:translateY(6px);}to{opacity:1;transform:translateY(0);}}

  /* ---------- Hero ---------- */
  .hero{padding:64px 0 40px;text-align:center;background:
    radial-gradient(600px 300px at 15% 0%, rgba(7,193,96,.10), transparent),
    radial-gradient(600px 300px at 85% 0%, rgba(7,193,96,.08), transparent);}
  .hero-badge{display:inline-flex;align-items:center;gap:7px;background:var(--green-light);color:var(--green-dark);font-size:.78rem;font-weight:700;padding:7px 14px;border-radius:30px;margin-bottom:18px;}
  .hero h1{font-size:2.5rem;font-weight:800;letter-spacing:-.02em;max-width:720px;margin:0 auto 16px;}
  .hero h1 span{color:var(--green);}
  .hero p{color:var(--ink-soft);font-size:1.05rem;max-width:560px;margin:0 auto 28px;}
  .hero-actions{display:flex;gap:12px;justify-content:center;flex-wrap:wrap;}
  .hero-stats{display:flex;gap:36px;justify-content:center;margin-top:44px;flex-wrap:wrap;}
  .hero-stats div{text-align:center;}
  .hero-stats .num{font-size:1.5rem;font-weight:800;color:var(--green-dark);}
  .hero-stats .lbl{font-size:.78rem;color:var(--ink-soft);}

  /* ---------- Section ---------- */
  .section{padding:44px 0;}
  .section-head{display:flex;align-items:flex-end;justify-content:space-between;margin-bottom:22px;flex-wrap:wrap;gap:10px;}
  .section-head h2{font-size:1.5rem;font-weight:800;}
  .section-head p{color:var(--ink-soft);font-size:.9rem;margin-top:4px;}
  .filter-chips{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:24px;}
  .chip{padding:8px 15px;border-radius:30px;background:#fff;border:1px solid var(--line);font-size:.82rem;font-weight:600;color:var(--ink-soft);}
  .chip.active{background:var(--ink);color:#fff;border-color:var(--ink);}

  /* ---------- Course grid/card ---------- */
  .course-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(270px,1fr));gap:20px;}
  .course-card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);transition:.18s;cursor:pointer;display:flex;flex-direction:column;}
  .course-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg);}
  .course-thumb{height:140px;display:flex;align-items:center;justify-content:center;font-size:2.6rem;position:relative;overflow:hidden;}
  .course-thumb img{width:100%;height:100%;object-fit:cover;}
  .course-thumb .owned-badge{position:absolute;top:10px;right:10px;background:var(--green);color:#fff;font-size:.68rem;font-weight:700;padding:4px 9px;border-radius:20px;z-index:2;}
  .course-body{padding:16px 18px 18px;display:flex;flex-direction:column;gap:8px;flex:1;}
  .course-cat{font-size:.72rem;font-weight:700;color:var(--green-dark);text-transform:uppercase;letter-spacing:.03em;}
  .course-body h3{font-size:1.02rem;font-weight:700;line-height:1.35;}
  .course-desc{font-size:.82rem;color:var(--ink-soft);flex:1;}
  .course-meta{display:flex;align-items:center;gap:10px;font-size:.75rem;color:var(--ink-soft);}
  .course-foot{display:flex;align-items:center;justify-content:space-between;margin-top:6px;padding-top:12px;border-top:1px solid var(--line);}
  .price{font-weight:800;font-size:1.05rem;color:var(--ink);}
  .price small{font-weight:500;color:var(--ink-soft);text-decoration:line-through;font-size:.78rem;margin-right:6px;}

  /* ---------- Course detail ---------- */
  .detail-hero{display:grid;grid-template-columns:1.3fr 1fr;gap:36px;padding:40px 0;align-items:start;}
  @media (max-width:820px){.detail-hero{grid-template-columns:1fr;}}
  .breadcrumb{font-size:.8rem;color:var(--ink-soft);margin-bottom:18px;display:flex;gap:6px;align-items:center;}
  .breadcrumb button{color:var(--green-dark);font-weight:600;}
  .detail-thumb{height:220px;border-radius:var(--radius);display:flex;align-items:center;justify-content:center;font-size:4rem;margin-bottom:20px;overflow:hidden;}
  .detail-thumb img{width:100%;height:100%;object-fit:cover;}
  .detail-hero h1{font-size:1.7rem;font-weight:800;margin-bottom:10px;}
  .detail-hero .course-desc{font-size:.95rem;line-height:1.7;}
  .curriculum{margin-top:24px;}
  .curriculum h4{font-size:.95rem;font-weight:700;margin-bottom:10px;}
  .lesson-row{display:flex;align-items:center;gap:12px;padding:12px 14px;border:1px solid var(--line);border-radius:10px;margin-bottom:8px;background:#fff;font-size:.86rem;}
  .lesson-row .num{width:24px;height:24px;border-radius:50%;background:var(--bg);display:flex;align-items:center;justify-content:center;font-size:.72rem;font-weight:700;color:var(--ink-soft);flex-shrink:0;}
  .lesson-row.locked{color:var(--ink-soft);}
  .lesson-row .lock-ic{margin-left:auto;color:var(--ink-soft);font-size:.9rem;}
  .lesson-row .play-ic{margin-left:auto;color:var(--green-dark);font-size:.9rem;font-weight:700;}

  .buy-card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow);position:sticky;top:90px;}
  .buy-price{font-size:2rem;font-weight:800;margin-bottom:4px;}
  .buy-price small{font-size:1rem;color:var(--ink-soft);text-decoration:line-through;font-weight:500;margin-right:8px;}
  .buy-sub{font-size:.8rem;color:var(--ink-soft);margin-bottom:18px;}
  .buy-feature{display:flex;gap:9px;align-items:flex-start;font-size:.83rem;color:var(--ink-soft);margin-bottom:10px;}
  .buy-feature .ic{color:var(--green-dark);font-weight:800;}
  .owned-panel{text-align:center;padding:14px;background:var(--green-light);border-radius:12px;color:var(--green-dark);font-weight:700;font-size:.88rem;}

  /* ---------- Modal ---------- */
  .modal-overlay{position:fixed;inset:0;background:rgba(15,20,25,.55);display:none;align-items:center;justify-content:center;z-index:200;padding:20px;}
  .modal-overlay.active{display:flex;}
  .modal{background:#fff;border-radius:18px;width:100%;max-width:420px;padding:28px;box-shadow:var(--shadow-lg);max-height:90vh;overflow-y:auto;position:relative;}
  .modal-close{position:absolute;top:16px;right:16px;font-size:1.1rem;color:var(--ink-soft);width:30px;height:30px;border-radius:50%;display:flex;align-items:center;justify-content:center;}
  .modal-close:hover{background:var(--bg);}
  .modal h3{font-size:1.15rem;font-weight:800;margin-bottom:6px;}
  .modal .sub{font-size:.83rem;color:var(--ink-soft);margin-bottom:20px;}
  .tab-switch{display:flex;background:var(--bg);border-radius:10px;padding:4px;margin-bottom:20px;}
  .tab-switch button{flex:1;padding:9px;border-radius:8px;font-size:.82rem;font-weight:700;color:var(--ink-soft);}
  .tab-switch button.active{background:#fff;color:var(--ink);box-shadow:var(--shadow);}
  .field{margin-bottom:14px;}
  .field label{display:block;font-size:.78rem;font-weight:700;color:var(--ink-soft);margin-bottom:6px;}
  .field input,.field select,.field textarea{width:100%;padding:11px 13px;border:1.5px solid var(--line);border-radius:10px;font-size:.9rem;font-family:inherit;}
  .field input:focus,.field select:focus,.field textarea:focus{outline:none;border-color:var(--green);}
  .otp-inputs{display:flex;gap:8px;margin-bottom:16px;}
  .otp-inputs input{width:100%;text-align:center;font-size:1.2rem;font-weight:700;padding:10px 0;}
  .google-btn{display:flex;align-items:center;justify-content:center;gap:10px;width:100%;padding:12px;border:1.5px solid var(--line);border-radius:10px;font-weight:700;font-size:.88rem;background:#fff;}
  .google-btn:hover{background:var(--bg);}
  .hint{font-size:.74rem;color:var(--ink-soft);background:var(--bg);padding:9px 11px;border-radius:8px;margin-top:6px;}

  /* Payment modal specifics */
  .qr-box{width:190px;height:190px;margin:0 auto 16px;border-radius:14px;background:
    repeating-linear-gradient(45deg,#1a1a1a 0 6px, #fff 6px 12px) center/70% 70% no-repeat,
    #fff;border:1.5px solid var(--line);display:flex;align-items:center;justify-content:center;position:relative;}
  .qr-box::before{content:"QPay QR";position:absolute;bottom:-26px;left:0;right:0;text-align:center;font-size:.72rem;color:var(--ink-soft);font-weight:700;}
  .invoice-box{background:var(--bg);border-radius:10px;padding:12px 14px;font-size:.8rem;display:flex;justify-content:space-between;margin:22px 0 16px;}
  .invoice-box b{font-family:monospace;}
  .pay-status{display:flex;align-items:center;gap:8px;justify-content:center;font-size:.82rem;color:var(--ink-soft);margin-bottom:16px;}
  .dot-pulse{width:8px;height:8px;border-radius:50%;background:var(--amber);animation:pulse 1.2s infinite;}
  @keyframes pulse{0%,100%{opacity:1;}50%{opacity:.3;}}
  .success-box{text-align:center;padding:20px 0;}
  .success-check{width:64px;height:64px;border-radius:50%;background:var(--green-light);color:var(--green-dark);font-size:2rem;display:flex;align-items:center;justify-content:center;margin:0 auto 16px;}

  /* ---------- Dashboard ---------- */
  .empty-state{text-align:center;padding:70px 20px;color:var(--ink-soft);}
  .empty-state .ic{font-size:2.4rem;margin-bottom:14px;}
  .empty-state h3{color:var(--ink);font-size:1.1rem;margin-bottom:6px;}

  /* ---------- Lesson / video player ---------- */
  .lesson-wrap{max-width:880px;margin:0 auto;padding:36px 0;}
  .video-frame{position:relative;background:#0d0f12;border-radius:16px;aspect-ratio:16/9;display:flex;align-items:center;justify-content:center;overflow:hidden;user-select:none;}
  .video-frame .play-btn{width:70px;height:70px;border-radius:50%;background:rgba(255,255,255,.14);border:2px solid rgba(255,255,255,.5);display:flex;align-items:center;justify-content:center;color:#fff;font-size:1.6rem;}
  .watermark{position:absolute;color:rgba(255,255,255,.35);font-size:.78rem;font-weight:700;pointer-events:none;white-space:nowrap;transition:top 4s linear, left 4s linear;}
  .protect-banner{display:flex;align-items:center;gap:10px;background:#fff4e5;color:#8a5a00;border:1px solid #ffe1ae;padding:12px 16px;border-radius:12px;font-size:.8rem;margin-top:16px;}
  .lesson-list-side{margin-top:26px;}
  .lesson-list-side .lesson-row{cursor:pointer;}
  .lesson-list-side .lesson-row.current{border-color:var(--green);background:var(--green-light);}

  /* ---------- Admin ---------- */
  .admin-shell{padding:36px 0;}
  .admin-tabs{display:flex;gap:6px;margin-bottom:26px;border-bottom:1px solid var(--line);}
  .admin-tabs button{padding:11px 16px;font-size:.86rem;font-weight:700;color:var(--ink-soft);border-bottom:2px solid transparent;}
  .admin-tabs button.active{color:var(--green-dark);border-color:var(--green);}
  .stat-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:14px;margin-bottom:28px;}
  .stat-card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px;}
  .stat-card .num{font-size:1.5rem;font-weight:800;}
  .stat-card .lbl{font-size:.78rem;color:var(--ink-soft);margin-top:2px;}
  table{width:100%;border-collapse:collapse;background:#fff;border:1px solid var(--line);border-radius:14px;overflow:hidden;}
  th,td{text-align:left;padding:13px 16px;font-size:.85rem;border-bottom:1px solid var(--line);}
  th{background:var(--bg);color:var(--ink-soft);font-weight:700;font-size:.74rem;text-transform:uppercase;letter-spacing:.03em;}
  tr:last-child td{border-bottom:none;}
  .status-pill{padding:4px 10px;border-radius:20px;font-size:.72rem;font-weight:700;}
  .status-pill.pub{background:var(--green-light);color:var(--green-dark);}
  .status-pill.draft{background:#f1f2f4;color:var(--ink-soft);}
  .row-actions{display:flex;gap:6px;}
  .price-input-row{display:flex;align-items:center;gap:10px;}
  .price-input-row input{width:130px;padding:8px 10px;border:1.5px solid var(--line);border-radius:8px;font-size:.86rem;font-weight:700;}
  .price-input-row input.changed{border-color:var(--amber);background:#fff9ec;}
  .save-hint{font-size:.72rem;color:var(--amber);font-weight:700;}
  .form-card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:22px;margin-bottom:24px;}
  .field-row{display:grid;grid-template-columns:1fr 1fr;gap:14px;}
  .toast{position:fixed;bottom:26px;left:50%;transform:translateX(-50%) translateY(20px);background:var(--ink);color:#fff;padding:13px 20px;border-radius:10px;font-size:.85rem;font-weight:600;opacity:0;pointer-events:none;transition:.25s;z-index:400;display:flex;align-items:center;gap:8px;}
  .toast.show{opacity:1;transform:translateX(-50%) translateY(0);}
  .toast .ic{color:var(--green);}

  .security-note{background:var(--bg);border:1px dashed var(--line);border-radius:12px;padding:16px 18px;font-size:.8rem;color:var(--ink-soft);line-height:1.7;margin-top:22px;}
  .security-note b{color:var(--ink);}

  footer{padding:40px 0;text-align:center;color:var(--ink-soft);font-size:.8rem;border-top:1px solid var(--line);margin-top:30px;}

  /* ================================================================
     Гар утасны дэлгэц — орчин үеийн, амьсгалах зайтай харагдацын тохиргоо
     Анхаар: доорх бүх утга нь desktop-ийн 24px-ээс БАГА болохгүй —
     гар утсанд зай багасгах биш, харин илүү уужим санагдуулахыг зорьсон.
     ================================================================ */
  @media (max-width:720px){
    .wrap{padding:0 24px;}
    .navbar .wrap{height:64px;}
    .nav-links{display:none;}

    .hero{padding:56px 0 44px;}
    .hero-badge{margin-bottom:20px;}
    .hero h1{font-size:2rem;line-height:1.28;margin-bottom:18px;}
    .hero p{font-size:1rem;line-height:1.6;margin-bottom:30px;}
    .hero-actions{flex-direction:column;align-items:stretch;gap:12px;}
    .hero-actions .btn{width:100%;padding:15px 22px;}
    .hero-stats{gap:28px;margin-top:40px;}

    .section{padding:48px 0;}
    .section-head{flex-direction:column;align-items:flex-start;gap:14px;margin-bottom:26px;}

    .course-grid{grid-template-columns:1fr;gap:18px;}
    .field-row{grid-template-columns:1fr;gap:12px;}

    .detail-hero{gap:30px;padding:32px 0;}
    .buy-card{position:static;padding:24px;}

    .btn{padding:14px 22px;font-size:.95rem;}
    .btn-sm{padding:9px 14px;}

    .stat-row{grid-template-columns:repeat(2,1fr);gap:12px;}
    .admin-tabs{overflow-x:auto;-webkit-overflow-scrolling:touch;}
    .admin-shell{padding:28px 0;}

    table{display:block;overflow-x:auto;-webkit-overflow-scrolling:touch;}
  }

  @media (max-width:380px){
    .hero h1{font-size:1.75rem;}
    .brand small{display:none;}
  }