.email-studio-viewport-toggle button,
.icon-button {
  display: inline-grid;
  place-items: center;
  width: 32px;
  height: var(--control-compact);
  padding: 0;
  border: 0;
  border-radius: 6px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
}

.email-studio-viewport-toggle button:hover,
.icon-button:hover { color: var(--navy); background: #fff; }
.email-studio-viewport-toggle button.active { color: var(--navy); background: #fff; box-shadow: 0 1px 5px rgba(20, 18, 61, .12); }
.email-studio-viewport-toggle button:disabled,
.icon-button:disabled { cursor: not-allowed; opacity: .35; }