popup.css

body {
  font-family: sans-serif;
}

.add-custom {
  background: none;
  border: none;
  height: 1.3rem;
  width: 1.3rem;
  border: 1px solid black;
  cursor: pointer;
}

.submit {
  margin: 1em 0 0 0.2em;
  padding: 0.4em 0.6em;
  border: none;
  background-color: black;
  color: white;
  font-weight: 700;
  cursor: pointer;
}

.submit:hover {
  background-color: #333;
}

.form-bottom {
  padding-top: 1em;
  display: grid;
  place-items: center;
}

fieldset input[type="text"] {
  display: none;
}

fieldset {
  position: relative;
  min-width: 18rem;
}

/* Switch and Sliders */
.switch {
  --switch-height: 1rem;
  --switch-width: 2rem;
  --switch-padding-h: 0.2rem;
  --switch-padding-v: 0.08rem;
  --slider-diameter: calc(var(--switch-width) / 2 - var(--switch-padding-h));
  --slider-transition: calc(
    var(--switch-width) - var(--slider-diameter) - 2 * var(--switch-padding-h)
  );
  position: absolute;
  right: 1rem;
  top: 0.3rem;
  display: inline-block;
  width: var(--switch-width);
  height: var(--switch-height);
}

.switch input {
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  border-radius: 0.5rem;
  background-color: #ccc;
  transition: 0.4s;
}

.slider:before {
  position: absolute;
  content: "";
  height: var(--slider-diameter);
  width: var(--slider-diameter);
  left: var(--switch-padding-h);
  top: var(--switch-padding-v);
  border-radius: 50%;
  background-color: #fff;
  transition: 0.4s;
}

.switch input:checked + .slider {
  background-color: #222;
}

.switch input:checked + .slider:before {
  transform: translateX(var(--slider-transition));
}