App.css

html {
  box-sizing: border-box;
}

*, *::before, *::after {
  box-sizing: inherit;
  margin: 0;
  padding: 0;
}

body {
  background-color: #f3f3f3;
}

.logout {
  border: none;
  outline: none;
  background: transparent;
  cursor: pointer;
}