:root{
  --primary-black:#0a0a0a;
  --secondary-black:#1a1a1a;
  --accent-red:#dc2626;
  --accent-red-light:#ef4444;
  --accent-red-dark:#b91c1c;
  --text-white:#f8fafc;
  --text-gray:#cbd5e1;
  --border-dark:#374151;
  --shadow-red:rgba(220,38,38,.2);
  --success-green:#10b981;
  --error-red:#ef4444;
  --info-blue:#3b82f6;
}

*{margin:0;padding:0;box-sizing:border-box}

body{
  font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;
  background:var(--primary-black);
  color:var(--text-white);
  line-height:1.6;
  min-height:100vh;
}

.container{
  width:100%;
  max-width:1400px;
  margin:0 auto;
  padding:0 1.5rem;
}

/* TOP BAR */
.trainer-topbar{
  background:var(--secondary-black);
  border-bottom:2px solid var(--accent-red);
  padding:1rem 0;
  position:sticky;
  top:0;
  z-index:100;
  box-shadow:0 4px 20px rgba(0,0,0,.5);
}
.trainer-topbar .container{
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:1rem;
  flex-wrap:wrap;
}
.trainer-title{
  color:var(--text-white);
  font-weight:700;
  font-size:1.2rem;
}
.trainer-actions{display:flex;gap:.75rem;flex-wrap:wrap}

/* BUTTONS */
.btn-trainer{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:.5rem;
  padding:.6rem 1.2rem;
  border-radius:8px;
  font-weight:600;
  cursor:pointer;
  transition:.2s;
  font-size:.95rem;
  background:transparent;
  color:var(--text-white);
  border:2px solid var(--border-dark);
  text-decoration:none;
  min-width:100px;
}
.btn-trainer:hover{
  border-color:var(--accent-red);
  color:var(--accent-red-light);
  transform:translateY(-2px);
  box-shadow:0 4px 12px var(--shadow-red);
}
.btn-trainer:disabled{
  opacity:.5;
  cursor:not-allowed;
  transform:none;
  box-shadow:none;
}
.btn-trainer.primary{
  background:linear-gradient(135deg,var(--accent-red),var(--accent-red-dark));
  border-color:var(--accent-red);
  color:#fff;
  box-shadow:0 4px 15px var(--shadow-red);
}
.btn-trainer.primary:hover{
  background:linear-gradient(135deg,var(--accent-red-dark),#991b1b);
  border-color:var(--accent-red-dark);
}

/* LAYOUT */
.trainer-layout{padding:2rem 0}

.trainer-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:2rem;
  margin-top:1.5rem;
}

.trainer-panel{
  background:var(--secondary-black);
  border:1px solid var(--border-dark);
  border-radius:12px;
  padding:1.5rem;
  box-shadow:0 10px 35px rgba(0,0,0,.4);
}

.trainer-panel h2,
.trainer-panel h3{
  color:var(--text-white);
  margin-bottom:1rem;
  font-weight:700;
}
.trainer-panel h2{
  font-size:1.5rem;
  border-bottom:2px solid var(--accent-red);
  padding-bottom:.5rem;
}
.trainer-panel h3{font-size:1.25rem}

.trainer-panel p,
.trainer-panel li{
  color:var(--text-gray);
  margin-bottom:.75rem;
}
.trainer-panel ul,
.trainer-panel ol{
  margin-left:1.5rem;
  margin-bottom:1rem;
}

/* LESSONS NAV */
.lessons-navigation{
  margin-bottom:1.5rem;
  padding:1.25rem;
  background:var(--secondary-black);
  border-radius:12px;
  border:1px solid var(--border-dark);
}
.lessons-navigation h3{
  margin-bottom:1rem;
  font-size:1.1rem;
  font-weight:600;
}
.lessons-list{display:flex;flex-wrap:wrap;gap:.75rem}

.lesson-link{
  display:inline-block;
  padding:.6rem 1rem;
  background:var(--primary-black);
  border:2px solid var(--border-dark);
  border-radius:8px;
  text-decoration:none;
  color:var(--text-gray);
  font-size:.9rem;
  font-weight:500;
  transition:.2s;
  min-width:60px;
  text-align:center;
}
.lesson-link:hover{
  border-color:var(--accent-red);
  color:var(--accent-red-light);
  transform:translateY(-2px);
  box-shadow:0 4px 12px var(--shadow-red);
}
.lesson-link.active{
  background:rgba(220,38,38,.1);
  border-color:var(--accent-red);
  color:var(--accent-red-light);
  font-weight:600;
}

/* PAGINATION */
.lesson-pagination{
  display:flex;
  justify-content:space-between;
  align-items:center;
  margin:1.5rem 0;
  padding:1rem 0;
  border-top:1px solid var(--border-dark);
  border-bottom:1px solid var(--border-dark);
}
.btn-pagination{
  padding:.7rem 1.5rem;
  background:var(--secondary-black);
  border:2px solid var(--border-dark);
  border-radius:8px;
  color:var(--text-white);
  font-weight:600;
  cursor:pointer;
  transition:.2s;
  min-width:160px;
}
.btn-pagination:hover:not(:disabled){
  border-color:var(--accent-red);
  color:var(--accent-red-light);
  transform:translateY(-2px);
  box-shadow:0 4px 12px var(--shadow-red);
}
.btn-pagination:disabled{opacity:.4;cursor:not-allowed;transform:none;box-shadow:none}
.progress-text{font-weight:700;color:var(--text-white);font-size:1.05rem}

/* HINT */
.hint{
  background:rgba(59,130,246,.1);
  border-left:4px solid var(--info-blue);
  padding:1rem;
  margin:1rem 0;
  border-radius:0 8px 8px 0;
}
.hint h4{color:var(--info-blue);margin-bottom:.5rem}

/* QUIZ OPTIONS (важно для логики тестирования) */
.options-list{display:flex;flex-direction:column;gap:10px}

.option-item{
  display:flex;
  align-items:flex-start;
  gap:10px;
  padding:10px 12px;
  border-radius:10px;
  border:1px solid var(--border-dark);
  background:rgba(255,255,255,.02);
  cursor:pointer;
  transition:.15s;
}
.option-item:hover{
  border-color:var(--accent-red);
  transform:translateY(-1px);
}
.option-item input{margin-top:3px}

.option-prefix{
  min-width:22px;
  font-weight:700;
  color:var(--text-white);
}
.option-text{color:var(--text-gray)}

.option-item.correct{
  border-color:var(--success-green);
  background:rgba(16,185,129,.12);
}
.option-item.incorrect{
  border-color:var(--error-red);
  background:rgba(239,68,68,.12);
}
.option-item.selected{
  box-shadow:0 0 0 2px rgba(220,38,38,.18);
}

.explanation-block{
  margin-top:12px;
  padding:12px;
  border-radius:10px;
  border:1px dashed rgba(203,213,225,.35);
  background:rgba(255,255,255,.02);
}
.explanation-block h4{margin-bottom:6px;color:var(--text-white)}
.explanation-block p{margin:0;color:var(--text-gray)}

.hidden{display:none}

/* MOBILE */
@media (max-width:1024px){
  .trainer-grid{grid-template-columns:1fr;gap:1.5rem}
}
@media (max-width:768px){
  .container{padding:0 1rem}
  .trainer-topbar .container{flex-direction:column;align-items:stretch}
  .trainer-actions{justify-content:center}
  .btn-trainer{flex:1;min-width:0}
  .trainer-title{text-align:center}
  .lesson-pagination{flex-direction:column;gap:1rem}
  .btn-pagination{width:100%;min-width:0}
  .progress-text{order:-1;margin-bottom:.5rem}
  .lessons-list{justify-content:center}
}