simple-theme-changer/src/themeChangerStyles.css

simple react component for a theme changer button

.theme-toggle,
.theme-toggle-checkbox,
.theme-toggle-label,
.theme-toggle-checkbox:checked+.theme-toggle-label,
.theme-toggle-icon,
.theme-toggle-checkbox+.theme-toggle-label .theme-toggle-icon.sun {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 60px;
  height: 30px;
  min-width: 60px;
  min-height: 30px;
}

.theme-toggle-checkbox {
  position: absolute;
  opacity: 0;
  z-index: -1;
}

.theme-toggle-label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  height: 100%;
  background-color: #333;
  border-radius: 15px;
  padding: 5px;
  transition: background-color 0.3s ease-in-out;
  cursor: pointer;
  position: relative;
}

.theme-toggle-checkbox:checked+.theme-toggle-label {
  background-color: #ddd;
}

.theme-toggle-icon {
  width: 20px;
  height: 20px;
  position: absolute;
  transition: transform 0.3s ease;
}

.theme-toggle-checkbox+.theme-toggle-label .theme-toggle-icon.sun {
  transform: translateX(30px);
}

.theme-toggle-icon.moon {
  transform: translateX(5px);
}