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

:root {
  --dark-mode: #222f3e;
  --light-mode: #fff;
}

body.light {
  --dark-mode: #fff;
  --light-mode: #222f3e;
}

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: var(--dark-mode);
  transition: all 0.4s ease;
}

.container {
  font-family: helvetica;
  border: 2px solid white;
  width: 300px;
  text-align: center;
  background-color: var(--light-mode);
  color: var(--light-mode);
  border-radius: 5px;
  transition: all 0.4s ease;
}

h2 {
  margin: 20px auto;
  background-color: var(--dark-mode);
  color: var(--light-mode);
  width: 140px;
  padding: 5px;
  border-radius: 2px;
  transition: all 0.4s ease;
}

.display {
  font-size: 28px;
  font-weight: 700;
  color: var(--dark-mode);
  transition: all 0.4s ease;
}

.buttons {
  margin: 20px;
}

.buttons .btn {
  font-size: 26px;
  font-weight: 700;
  border-radius: 50%;
  border: none;
  outline: none;
  cursor: pointer;
  background-color: var(--dark-mode);
  color: var(--light-mode);
  width: 40px;
  height: 40px;
  transition: all 0.4s ease;
}

.toggler {
  position: absolute;
  top: 20px;
  left: 40px;
  padding: 10px;
  font-size: 16px;
  border-radius: 2px;
  border: none;
  cursor: pointer;
  outline: none;
  color: var(--dark-mode);
  background-color: var(--light-mode);
  transition: all 0.4s ease;
}