:root {
  --transition: all ease .5s;
  --color1: #f5f5f5;
  --color2: #1E1E1E;
  --color3: #c7c6c6;
}

.dark-theme {
  --color1: #121212;
  --color2: #F5F5F5;
  --color3: #1E1E1E;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

.main {
  background-color: var(--color1);
  transition: var(--transition);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.toggle-btn {
  background-color: var(--color3);
  color: var(--color2);
  width: 300px;
  height: 300px;
  border-radius: 50%;
  border: none;
  cursor: pointer;
  display: grid;
  place-content: center;
}

.toggle-btn svg {
  transition: var(--transition);
}

.toggle-btn:hover svg {
  rotate: 180deg;
}

.toggle-btn svg:last-child {
  display: none;
}

.dark-theme .toggle-btn svg:last-child {
  display: block;
}

.dark-theme .toggle-btn svg:first-child {
  display: none;
}