.module-layout {
  display:grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 22px;
}
.sidebar {
  position: sticky;
  top: 92px;
  align-self:start;
  padding: 18px;
}
.sidebar h3 { margin: 0 0 14px; }
.sidebar a {
  display:block;
  color: var(--muted);
  text-decoration:none;
  padding: 10px 12px;
  border-radius: 12px;
  border:1px solid transparent;
}
.sidebar a:hover { color: var(--text); background: rgba(255,255,255,.035); border-color: rgba(255,255,255,.08); }
.lesson-main { display:grid; gap: 20px; }
.lesson-header {
  padding: clamp(24px, 4vw, 40px);
  position:relative;
  overflow:hidden;
}
.lesson-header::before {
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background: radial-gradient(circle at 84% 24%, rgba(45,226,255,.12), transparent 28%), radial-gradient(circle at 16% 82%, rgba(183,108,255,.08), transparent 30%);
}
.lesson-header > * { position:relative; z-index:2; }
.lesson-header h1 {
  margin: 10px 0 14px;
  font-size: clamp(2.1rem, 4vw, 4.4rem);
  line-height: 1.02;
  letter-spacing: -.045em;
}
.lesson-header .lesson-author { color: var(--muted); font-weight: 700; }
.lesson-block {
  padding: 24px;
}
.lesson-block h2 { margin: 0 0 14px; font-size: 1.55rem; }
.lesson-block p, .lesson-block li { color: var(--muted); line-height: 1.78; }
.objectives {
  display:grid;
  grid-template-columns: repeat(2, minmax(0,1fr));
  gap: 12px;
  padding: 0;
  list-style:none;
}
.objectives li {
  padding: 15px;
  border-radius: 16px;
  background: rgba(255,255,255,.035);
  border:1px solid rgba(255,255,255,.07);
}
.explain-grid, .calc-grid, .application-grid {
  display:grid;
  grid-template-columns: repeat(2, minmax(0,1fr));
  gap: 14px;
}
.explain-card, .calc-card, .application-card {
  padding: 17px;
  border-radius: 18px;
  background: rgba(255,255,255,.035);
  border:1px solid rgba(255,255,255,.07);
}
.formula-display {
  padding: 20px;
  border-radius: 20px;
  background: rgba(3,8,15,.82);
  border:1px solid rgba(45,226,255,.20);
  color: #c1fff7;
  font-size: clamp(1.15rem, 2vw, 1.7rem);
  font-weight: 900;
  overflow-x:auto;
}
.lesson-nav {
  display:flex;
  justify-content:space-between;
  gap: 12px;
  flex-wrap:wrap;
  padding: 18px;
}
.quiz-card {
  padding: 16px;
  border-radius: 18px;
  background: rgba(255,255,255,.035);
  border:1px solid rgba(255,255,255,.08);
  margin-bottom: 14px;
}
.quiz-options { display:flex; flex-direction:column; gap: 8px; margin-top: 12px; }
.quiz-options button {
  text-align:left;
  border:1px solid rgba(255,255,255,.08);
  background: rgba(255,255,255,.035);
  color: var(--text);
  padding: 12px 13px;
  border-radius: 12px;
  cursor:pointer;
}
.quiz-options button.correct { border-color: rgba(53,242,160,.5); background: rgba(53,242,160,.12); }
.quiz-options button.wrong { border-color: rgba(255,79,109,.5); background: rgba(255,79,109,.12); }
.answer-feedback { color: var(--muted); min-height: 24px; margin-top: 9px; }
@media(max-width: 1180px) {
  .module-layout { grid-template-columns: 1fr; }
  .sidebar { position:relative; top:0; }
  .objectives, .explain-grid, .calc-grid, .application-grid { grid-template-columns: 1fr; }
}

/* v09 deep academic blocks */
.deep-learning-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.deep-card {
  padding: 18px;
  border-radius: 18px;
  background: rgba(255,255,255,.035);
  border: 1px solid rgba(255,255,255,.08);
}

.deep-card strong {
  display: block;
  color: #dffaff;
  margin-bottom: 8px;
  font-size: .98rem;
}

.deep-card p {
  margin: 0;
}

.runtime-diagnostics {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 90;
  display: grid;
  gap: 2px;
  max-width: min(360px, calc(100vw - 36px));
  padding: 12px 14px;
  border-radius: 16px;
  background: rgba(5,8,15,.82);
  border: 1px solid rgba(255,255,255,.10);
  box-shadow: 0 18px 42px rgba(0,0,0,.38);
  backdrop-filter: blur(12px);
  font-size: .82rem;
}

.runtime-diagnostics strong {
  color: var(--text);
  letter-spacing: .06em;
  text-transform: uppercase;
  font-size: .72rem;
}

.runtime-diagnostics span {
  color: var(--muted);
  line-height: 1.35;
}

.runtime-ok { border-color: rgba(53,242,160,.22); }
.runtime-warn { border-color: rgba(255,184,77,.36); }

@media(max-width: 720px) {
  .deep-learning-grid { grid-template-columns: 1fr; }
  .runtime-diagnostics { display: none; }
}