/* ═══════════════════════════════════════════════════════
   Electromagnetic Induction — Clay Design System Extensions
   ═══════════════════════════════════════════════════════ */

/* ── Sidebar Toggle Button ── */
.sidebar-toggle {
  display: none;
  position: fixed;
  top: 72px;
  left: 12px;
  z-index: 200;
  align-items: center;
  gap: 6px;
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid rgba(160,150,180,0.15);
  border-radius: 20px;
  padding: 8px 14px;
  font-family: var(--font-heading);
  font-size: 13px;
  font-weight: 700;
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--dur-fast) var(--ease-smooth);
  box-shadow: var(--shadow-card);
}
.sidebar-toggle:hover {
  background: rgba(255,255,255,1);
  border-color: var(--accent);
  color: var(--accent);
}
.sidebar-toggle i {
  font-size: 14px;
}

/* ── Content Sidebar ── */
.content-sidebar {
  position: fixed;
  top: 64px;
  left: 0;
  bottom: 0;
  z-index: 150;
  width: 220px;
  background: rgba(255,255,255,0.80);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-right: 1px solid rgba(160,150,180,0.12);
  overflow-y: auto;
  padding: 20px 0;
  transition: transform 0.35s var(--ease-smooth);
  display: flex;
  flex-direction: column;
  scrollbar-width: thin;
  scrollbar-color: rgba(160,150,180,0.2) transparent;
}
.content-sidebar::-webkit-scrollbar { width: 4px; }
.content-sidebar::-webkit-scrollbar-thumb { background: rgba(160,150,180,0.2); border-radius: 4px; }

.content-sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 20px 16px;
  border-bottom: 1px solid rgba(160,150,180,0.08);
  margin-bottom: 12px;
}
.content-sidebar-brand {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 15px;
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}
.sidebar-close {
  display: none;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 18px;
  cursor: pointer;
  padding: 4px;
  border-radius: 8px;
  transition: all var(--dur-fast);
}
.sidebar-close:hover {
  background: rgba(160,150,180,0.1);
  color: var(--text-primary);
}

.content-sidebar-links {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 0 12px;
}
.content-sidebar-link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: 12px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  text-decoration: none;
  transition: all var(--dur-fast) var(--ease-smooth);
  font-family: var(--font-heading);
}
.content-sidebar-link:hover {
  background: rgba(124,58,237,0.06);
  color: var(--text-primary);
}
.content-sidebar-link.active {
  background: rgba(124,58,237,0.1);
  color: var(--accent);
}
.sidebar-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border-radius: 8px;
  background: rgba(160,150,180,0.1);
  font-size: 11px;
  font-weight: 800;
  color: var(--text-muted);
  flex-shrink: 0;
  transition: all var(--dur-fast);
}
.content-sidebar-link.active .sidebar-num {
  background: rgba(124,58,237,0.15);
  color: var(--accent);
}
.sidebar-label {
  line-height: 1.2;
}

/* ── Content Main (wrapper) ── */
.content-main {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 24px;
  transition: all 0.35s var(--ease-smooth);
}

h1 {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: clamp(2rem,4vw,3rem);
  text-align: center;
  color: var(--text-primary);
  margin-bottom: 32px;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.learning-outcomes {
  background: rgba(124,58,237,0.04);
  border-left: 4px solid var(--accent);
  border-radius: 16px;
  padding: 16px 20px;
  margin-bottom: 20px;
}
.learning-outcomes h4 {
  font-family: var(--font-heading);
  font-size: 14px;
  color: var(--accent);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.learning-outcomes ul {
  list-style: none;
  padding: 0;
}
.learning-outcomes li {
  font-size: 14px;
  color: var(--text-muted);
  padding: 4px 0;
  padding-left: 20px;
  position: relative;
}
.learning-outcomes li::before {
  content: "\2713";
  position: absolute;
  left: 0;
  color: var(--accent-emerald);
  font-weight: 700;
}

.formula {
  background: linear-gradient(135deg,rgba(124,58,237,0.05),rgba(219,39,119,0.04));
  border-radius: 20px;
  padding: 20px 24px;
  margin: 16px 0;
  text-align: center;
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
}

.example {
  background: rgba(245,158,11,0.04);
  border-left: 4px solid var(--accent-amber);
  border-radius: 16px;
  padding: 14px 18px;
  margin: 14px 0;
  font-size: 14px;
  color: var(--text-muted);
}
.example p {
  color: var(--text-muted);
}
.example ul {
  padding-left: 20px;
  margin-top: 8px;
}
.example li {
  margin-bottom: 4px;
}

.explanation {
  background: rgba(14,165,233,0.04);
  border-left: 4px solid var(--accent-blue);
  border-radius: 16px;
  padding: 14px 18px;
  margin: 14px 0;
  font-size: 14px;
  color: var(--text-muted);
  font-style: italic;
}

.sim-wrapper {
  background: linear-gradient(135deg,rgba(16,185,129,0.04),rgba(14,165,233,0.03));
  border: 1px solid rgba(160,150,180,0.1);
  border-radius: 24px;
  padding: 24px;
  margin: 20px 0;
  transition: all var(--dur-med) var(--ease-smooth);
}
.sim-wrapper:hover {
  border-color: rgba(124,58,237,0.25);
}
.sim-header h4 {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 8px;
}
.sim-header p {
  font-size: 14px;
  color: var(--text-muted);
  margin-bottom: 12px;
}
.sim-body {
  position: relative;
  width: 100%;
  border-radius: 16px;
  overflow: hidden;
  background: #f8f7fc;
  border: 1px solid rgba(160,150,180,0.08);
}
.sim-body canvas {
  display: block;
  width: 100%;
  height: auto;
}
.sim-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  margin-top: 12px;
}
.sim-control-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.sim-control-group label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  font-family: var(--font-heading);
}
.sim-control-group input[type="range"] {
  accent-color: var(--accent);
  width: 130px;
}
.sim-readout {
  display: inline-block;
  background: rgba(124,58,237,0.06);
  border: 1px solid rgba(124,58,237,0.12);
  border-radius: 14px;
  padding: 4px 12px;
  font-size: 13px;
  font-family: var(--font-heading);
  font-weight: 600;
  color: var(--accent);
  margin-left: 8px;
}

/* Button overrides */
.sim-btn,.quiz-btn,.sim-wrapper button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: none;
  border-radius: var(--radius-btn);
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  padding: 10px 22px;
  cursor: pointer;
  transition: all var(--dur-fast);
  text-decoration: none;
  line-height: 1;
  min-height: 44px;
  background: linear-gradient(135deg,var(--accent-light),var(--accent));
  color: #fff;
  box-shadow: var(--shadow-btn);
}
.sim-btn:hover,.quiz-btn:hover,.sim-wrapper button:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-btn-hover);
}
.sim-btn:active,.quiz-btn:active,.sim-wrapper button:active {
  transform: scale(0.95);
  box-shadow: var(--shadow-pressed);
}
.secondary,.sim-btn.secondary {
  background: #fff !important;
  color: var(--text-primary) !important;
  box-shadow: var(--shadow-btn) !important;
}
.secondary:hover,.sim-btn.secondary:hover {
  transform: translateY(-2px) !important;
  box-shadow: var(--shadow-btn-hover) !important;
}

.quiz-container {
  background: rgba(255,255,255,0.4);
  border: 1px solid rgba(160,150,180,0.1);
  border-radius: 24px;
  padding: 24px;
}
.quiz-question {
  background: rgba(255,255,255,0.5);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid rgba(160,150,180,0.1);
  border-radius: 20px;
  padding: 20px;
  margin-bottom: 16px;
  transition: all var(--dur-med) var(--ease-smooth);
}
.quiz-question:hover {
  background: rgba(255,255,255,0.7);
}
.quiz-question p {
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
  font-family: var(--font-heading);
}
.quiz-question label {
  display: block;
  padding: 8px 14px;
  margin: 4px 0;
  border-radius: 14px;
  font-size: 14px;
  color: var(--text-muted);
  cursor: pointer;
  transition: background var(--dur-fast);
}
.quiz-question label:hover {
  background: rgba(124,58,237,0.05);
}
.quiz-question input[type="radio"] {
  margin-right: 10px;
  accent-color: var(--accent);
}

.result {
  background: rgba(16,185,129,0.06);
  border: 1px solid rgba(16,185,129,0.2);
  border-radius: 20px;
  padding: 16px 20px;
  margin-top: 16px;
  text-align: center;
  font-weight: 700;
  color: var(--accent-emerald);
}

.footer {
  text-align: center;
  color: var(--text-muted);
  padding: 24px;
  font-size: 13px;
}

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s var(--ease-smooth),transform 0.6s var(--ease-smooth);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width:768px) {
  .sidebar-toggle { display: flex; }
  .content-sidebar {
    transform: translateX(-100%);
    width: 260px;
  }
  .content-sidebar.open {
    transform: translateX(0);
  }
  .sidebar-close { display: block; }
  .content-main {
    padding: 0 16px;
    margin-left: 0;
  }
  .content-sidebar-links { justify-content: flex-start; }
  .sim-wrapper,.card { padding: 16px; }
}