:root{
  --primary:#4b2e83;--primary-2:#6a3fb5;--success:#16a34a;--danger:#dc2626;
  --wa:#25D366;--bg:#eef1f8;--card:#fff;--text:#1f2340;--muted:#6b7280;
  --line:#e3ddf5;--radius:16px;--shadow:0 8px 30px rgba(75,46,131,.10);
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
html,body{margin:0;padding:0}
body{font-family:"Segoe UI",Tahoma,system-ui,-apple-system,sans-serif;background:var(--bg);color:var(--text);line-height:1.7;min-height:100vh;display:flex;justify-content:center;padding:16px;font-size:16px}
.app{width:100%;max-width:820px}
.screen{display:none;animation:fade .25s ease}
.screen.active{display:block}
@keyframes fade{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.card{background:var(--card);border-radius:var(--radius);padding:26px;box-shadow:var(--shadow)}
.badge{display:inline-block;background:#f0ecfa;color:var(--primary);padding:4px 12px;border-radius:999px;font-size:13px;font-weight:700;margin-bottom:10px}
h1{font-size:1.45rem;margin:6px 0 14px;color:var(--primary)}
.muted{color:var(--muted);font-size:.95rem}
.field{display:block;margin:18px 0}
.field span{display:block;font-weight:600;margin-bottom:6px;font-size:.92rem}
input[type=text]{width:100%;padding:14px 16px;border:2px solid var(--line);border-radius:12px;font-size:1rem;text-align:right;background:#fafbff;transition:.2s}
input[type=text]:focus{outline:none;border-color:var(--primary-2);background:#fff}
.btn{display:inline-block;padding:13px 22px;border:none;border-radius:12px;font-size:1rem;font-weight:700;cursor:pointer;text-align:center;text-decoration:none;transition:.2s;width:100%;margin-top:10px}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{background:var(--primary-2)}
.btn-secondary{background:#e2e8f0;color:var(--text)}
.btn-secondary:hover{background:#cbd5e1}
.btn-success{background:var(--success);color:#fff}
.btn-success:hover{background:#15803d}
.btn-whatsapp{background:var(--wa);color:#fff}
.btn-whatsapp:hover{background:#1da851}
.hidden{display:none!important}
.quiz-header{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap;background:var(--card);padding:14px 18px;border-radius:var(--radius);box-shadow:var(--shadow);margin-bottom:14px}
.exam-title{font-weight:700;color:var(--primary);font-size:1rem;display:block}
.timer{background:#4b2e83;color:#fff;padding:8px 16px;border-radius:999px;font-weight:700;font-size:1rem;font-variant-numeric:tabular-nums}
.timer.danger{background:var(--danger);animation:pulse 1s infinite}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.6}}
.progress-wrap{display:flex;align-items:center;gap:10px;margin-bottom:14px}
.progress-bar{flex:1;height:8px;background:#e2e8f0;border-radius:8px;overflow:hidden}
#progressFill{height:100%;width:0%;background:linear-gradient(90deg,var(--primary),var(--primary-2));transition:width .3s}
.progress-text{font-size:.85rem;color:var(--muted);white-space:nowrap;font-weight:600}
.question-container{background:var(--card);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow);min-height:280px}
.question p.stem{font-size:1.05rem;font-weight:600;margin:0 0 18px;color:#2a1a5e;line-height:2}
.qnum{display:inline-flex;align-items:center;justify-content:center;background:var(--primary-2);color:#fff;width:28px;height:28px;border-radius:50%;font-size:13px;font-weight:700;margin-left:8px}
.option{display:flex;align-items:center;gap:10px;background:#faf8ff;border:2px solid var(--line);padding:14px 16px;border-radius:12px;margin-bottom:10px;cursor:pointer;transition:.15s;font-size:1rem}
.option:hover{background:#f0ecfa;border-color:#c9b8ee}
.option.selected{border-color:var(--primary);background:#ede7fb;box-shadow:0 0 0 3px rgba(75,46,131,.12)}
.option.correct{border-color:var(--success);background:#dcfce7}
.option.wrong{border-color:var(--danger);background:#fee2e2}
.option .letter{background:var(--primary-2);color:#fff;width:28px;height:28px;border-radius:8px;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:14px;flex-shrink:0}
.option.selected .letter{background:var(--primary)}
.option.correct .letter{background:var(--success)}
.option.wrong .letter{background:var(--danger)}
.quiz-footer{display:flex;gap:10px;margin-top:14px}
.quiz-footer .btn{flex:1}
.score{font-size:1.4rem;text-align:center;margin:18px 0;font-weight:800;color:var(--primary)}
.review{max-height:60vh;overflow-y:auto;padding-left:6px;margin-bottom:10px}
.review-item{border-right:4px solid var(--primary);padding:12px 14px;margin-bottom:10px;background:#f8fafc;border-radius:10px;font-size:.95rem;line-height:1.9}
.review-item.correct{border-color:var(--success);background:#f0fdf4}
.review-item.wrong{border-color:var(--danger);background:#fef2f2}
.review-item .rev-head{font-weight:700;margin-bottom:6px}
.review-item .rev-line{margin:3px 0}
.review-item .rev-correct{color:var(--success);font-weight:600}
.review-item .rev-wrong{color:var(--danger);font-weight:600}
.lessons{margin-top:12px}
.unit-block{margin-bottom:20px}
.unit-title{background:var(--primary);color:#fff;padding:10px 16px;border-radius:10px;font-weight:700;font-size:1rem;margin-bottom:10px}
.lesson-item{display:flex;justify-content:space-between;align-items:center;padding:12px 16px;background:#faf8ff;border:1px solid var(--line);border-radius:10px;margin-bottom:8px;cursor:pointer;transition:.2s;text-decoration:none;color:inherit;font-weight:600}
.lesson-item:hover{background:#ede7fb;border-color:var(--primary-2);transform:translateX(-3px)}
.lesson-item .arrow{color:var(--primary-2);font-weight:700}
.exam-item{background:#fff7ed;border-color:#fdba74;color:#9a3412}
.exam-item:hover{background:#ffedd5}
.exam-item .arrow{color:#ea580c}
.stage-links{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:16px;padding-bottom:16px;border-bottom:1px solid var(--line)}
.stage-links a{flex:1;min-width:110px;text-align:center;padding:9px 12px;background:#f0ecfa;color:var(--primary);border-radius:10px;text-decoration:none;font-size:.85rem;font-weight:700}
.stage-links a:hover{background:var(--primary);color:#fff}
.stage-links a.active{background:var(--primary);color:#fff}
.leaderboard{margin:14px 0}
.leader-item{display:flex;justify-content:space-between;align-items:center;padding:12px 16px;border-bottom:1px solid var(--line);font-weight:600;gap:10px}
.leader-item:first-child{background:linear-gradient(90deg,#fef3c7,#fde68a);border-radius:10px;border-bottom:none}
.leader-item:nth-child(2){background:#f1f5f9;border-radius:10px}
.leader-item:nth-child(3){background:#fef3c7;border-radius:10px}
.leader-item .rank{background:var(--primary);color:#fff;width:30px;height:30px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:14px;flex-shrink:0}
.leader-item:first-child .rank{background:#d97706}
.leader-item .name{flex:1;text-align:right}
.leader-item .pct{color:var(--primary);font-weight:800;font-variant-numeric:tabular-nums}
.leader-item .date{color:var(--muted);font-size:.78rem;font-weight:400}
@media (max-width:640px){
  body{padding:10px;font-size:15px}
  .card{padding:18px;border-radius:14px}
  h1{font-size:1.2rem}
  .question-container{padding:16px;min-height:240px}
  .question p.stem{font-size:1rem;line-height:1.9}
  .option{padding:12px 14px;font-size:.95rem}
  .quiz-header{padding:12px 14px}
  .timer{font-size:.92rem;padding:6px 12px}
  .exam-title{font-size:.92rem}
  .btn{padding:12px 16px;font-size:.95rem}
  .quiz-footer{flex-direction:column}
  .score{font-size:1.15rem}
  mjx-container{font-size:.92em!important}
}
mjx-container{max-width:100%;overflow-x:auto;overflow-y:hidden}