:root{
  --primary:#1f3864;
  --accent:#2e75b6;
  --gold:#c9a227;
  --bg:#f5f7fa;
  --card:#ffffff;
  --text:#222;
  --muted:#666;
  --success:#2e8b57;
  --danger:#c0392b;
  --border:#ddd;
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:'Segoe UI',Roboto,Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.6}
.container{max-width:1100px;margin:0 auto;padding:0 20px}
.topbar{background:var(--primary);color:#fff;padding:12px 0;position:sticky;top:0;z-index:100;box-shadow:0 2px 6px rgba(0,0,0,.15)}
.topbar .container{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:10px}
.brand{color:#fff;text-decoration:none;font-size:1.4rem;font-weight:700}
nav a{color:#fff;text-decoration:none;margin-left:14px;font-size:.95rem}
nav a:hover{text-decoration:underline}
.user{margin-left:14px;opacity:.85;font-size:.9rem}
.btn{display:inline-block;padding:8px 16px;border-radius:6px;text-decoration:none;border:none;cursor:pointer;font-size:.95rem;transition:.15s}
.btn-primary{background:var(--accent);color:#fff}
.btn-primary:hover{background:#1f5fa0}
.btn-sm{padding:5px 12px;font-size:.85rem}
.btn-success{background:var(--success);color:#fff}
.btn-danger{background:var(--danger);color:#fff}
.btn-outline{background:transparent;border:1px solid var(--accent);color:var(--accent)}
.progress-bar{height:4px;background:rgba(255,255,255,.2)}
.progress-fill{height:100%;background:var(--gold);transition:width .3s}
main{padding:24px 0 60px}
.footer{background:#e9ecf1;padding:20px 0;margin-top:40px;font-size:.85rem;color:var(--muted)}
.card{background:var(--card);border-radius:10px;padding:24px;box-shadow:0 2px 8px rgba(0,0,0,.06);margin-bottom:20px}
.card h2,.card h3{color:var(--primary);margin-bottom:12px}
.grid{display:grid;gap:16px}
.grid-2{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}
.grid-3{grid-template-columns:repeat(auto-fit,minmax(220px,1fr))}
.module-card{border-left:4px solid var(--accent);transition:transform .15s}
.module-card:hover{transform:translateY(-3px)}
.module-card.done{border-left-color:var(--success)}
.badge{display:inline-block;padding:3px 10px;border-radius:12px;font-size:.75rem;font-weight:600;background:#e0e6f0;color:var(--primary)}
.badge-done{background:#d6f0e0;color:var(--success)}
.badge-lock{background:#eee;color:#999}
.lesson-content h1,.lesson-content h2,.lesson-content h3{color:var(--primary);margin:18px 0 8px}
.lesson-content p{margin:10px 0}
.lesson-content ul,.lesson-content ol{margin:10px 0 10px 24px}
.lesson-content li{margin:4px 0}
.lesson-content table{width:100%;border-collapse:collapse;margin:14px 0}
.lesson-content th,.lesson-content td{border:1px solid var(--border);padding:8px 10px}
.lesson-content th{background:var(--primary);color:#fff}
.lesson-content .formula{background:#f0f4fa;padding:12px 16px;border-left:4px solid var(--gold);font-family:monospace;margin:12px 0;border-radius:4px}
.lesson-content .callout{background:#fff8e1;border-left:4px solid var(--gold);padding:12px 16px;margin:12px 0;border-radius:4px}
.lesson-content .case-box{background:#e8f1fa;border-left:4px solid var(--accent);padding:12px 16px;margin:12px 0;border-radius:4px}
.hero{background:linear-gradient(135deg,var(--primary),var(--accent));color:#fff;padding:40px 24px;border-radius:12px;margin-bottom:24px}
.hero h1{font-size:2rem;margin-bottom:8px}
.quiz-option{display:block;padding:12px 16px;border:1px solid var(--border);border-radius:8px;margin:8px 0;cursor:pointer;transition:.15s}
.quiz-option:hover{border-color:var(--accent);background:#f0f6fc}
.quiz-option input{margin-right:8px}
.quiz-result{padding:16px;border-radius:8px;margin:16px 0;font-weight:600}
.quiz-result.ok{background:#d6f0e0;color:var(--success)}
.quiz-result.bad{background:#fde2e2;color:var(--danger)}
.exercise-box{background:#f9fafc;border:1px dashed var(--accent);padding:16px;border-radius:8px;margin:14px 0}
.answer-reveal{background:#f0f4fa;padding:12px 16px;border-radius:6px;margin-top:10px;display:none}
.stat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:12px;margin:16px 0}
.stat{background:var(--card);padding:14px;border-radius:8px;text-align:center;box-shadow:0 1px 4px rgba(0,0,0,.05)}
.stat .num{font-size:1.6rem;font-weight:700;color:var(--primary)}
.stat .lbl{font-size:.8rem;color:var(--muted)}
.form-group{margin-bottom:14px}
.form-group label{display:block;margin-bottom:4px;font-weight:600;font-size:.9rem}
.form-group input,.form-group textarea,.form-group select{width:100%;padding:10px 12px;border:1px solid var(--border);border-radius:6px;font-size:.95rem}
.form-group input:focus{border-color:var(--accent);outline:none}
.alert{padding:12px 16px;border-radius:6px;margin:12px 0}
.alert-error{background:#fde2e2;color:var(--danger)}
.alert-success{background:#d6f0e0;color:var(--success)}
.muted{color:var(--muted);font-size:.85rem}
.text-center{text-align:center}
.mt-2{margin-top:12px}
.mb-2{margin-bottom:12px}
a.link{color:var(--accent)}
table.data{width:100%;border-collapse:collapse;margin:12px 0}
table.data th,table.data td{border:1px solid var(--border);padding:8px}
table.data th{background:var(--primary);color:#fff}
@media(max-width:600px){.topbar .container{flex-direction:column;align-items:flex-start}}