@keyframes pulse {
  0%, 100% {
    transform: scale(1);
    opacity: 1;
  }
  50% {
    transform: scale(1.15);
    opacity: 0.75;
  }
}

@keyframes slideDownToast {
  from {
    transform: translateY(-30px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeIn 0.25s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes shimmer {
  0% {
    background-position: -200% 0;
  }
  100% {
    background-position: 200% 0;
  }
}

.skeleton {
  background: linear-gradient(90deg, var(--bg-card-subtle) 25%, var(--border-color) 50%, var(--bg-card-subtle) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

/* Floating Action Button (FAB) for Teacher / Student quick action */
.fab-btn {
  position: absolute;
  bottom: calc(var(--nav-height) + 16px);
  right: 20px;
  width: 54px;
  height: 54px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  box-shadow: 0 10px 25px rgba(79, 70, 229, 0.4);
  cursor: pointer;
  z-index: 45;
  transition: all 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
  border: none;
}

.fab-btn:hover {
  transform: scale(1.08) rotate(90deg);
}

.fab-btn:active {
  transform: scale(0.95);
}

/* Tab filter pills */
.tab-pills {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding: 4px 2px 12px 2px;
  scrollbar-width: none;
}

.tab-pills::-webkit-scrollbar {
  display: none;
}

.pill-btn {
  padding: 8px 16px;
  border-radius: var(--radius-full);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 700;
  white-space: nowrap;
  cursor: pointer;
  transition: all 0.2s ease;
}

.pill-btn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
  box-shadow: 0 3px 10px var(--primary-glow);
}