Notification Bell with Alert in Pure Javascript & CSS

@import url("https://fonts.googleapis.com/css?family=Noto+Sans+JP:400,500&display=swap");
 
* {
  box-sizing: border-box;
  padding: 0;
  margin: 0;
}
body {
  min-height: 100vh;
  background: hsl(0, 0%, 100%);
  font-family: "Noto Sans JP", sans-serif;
}
/* display the wrapping container in the top right corner of the viewport */
.notification {
  position: fixed;
  top: 0.5rem;
  right: 1rem;
  /* align the content to the rigth */
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  color: hsl(0, 0%, 20%);
  /* hide the overflow to conceal the message when translated to the right of the container */
  overflow-x: hidden;
  /* padding to avoid cropping the box-shadow on the message */
  padding: 0.25rem;
}
 
/* reduce the size of the icon and give a white fill to the elements of the graphic */
.notification__bell {
  display: block;
  width: 48px;
  height: auto;
  fill: hsl(0, 0%, 100%);
}
/* when the .notification container is given a class of .received animate the body and clapper of the bell to swing
! animate the clapper with a slight delay as to follow through the animation of the main body
*/
.notification.received .bell__body {
  animation: swingBody 0.7s 0.02s cubic-bezier(0.455, 0.03, 0.515, 0.955);
}
.notification.received .bell__clapper {
  animation: swingClapper 0.7s 0.04s cubic-bezier(0.455, 0.03, 0.515, 0.955);
}
/* ! for both elements the rotation occurs using the parent group element as a hinge, allowing for the pendulum-like swing */
@keyframes swingBody {
  25% {
    transform: rotate(-5deg);
  }
  75% {
    transform: rotate(5deg);
  }
}
/* animation for the clapper, following the main body and with a larger rotation */
@keyframes swingClapper {
  5% {
    transform: rotate(0deg);
  }
  30% {
    transform: rotate(-8deg);
  }
  80% {
    transform: rotate(8deg);
  }
}
 
/* style the content of the message to show a grid with the dismiss button in the top right corner
|h1  |  button |
|p   |p        |
*/
.notification__message {
  display: grid;
  grid-gap: 0.2rem;
  grid-template-columns: 1fr auto;
  padding: 0.5rem 1rem;
  margin: 1rem 0;
  /* style the div as a rounded rectangle with a border on the left segment */
  background: hsl(0, 0%, 100%);
  border-radius: 10px;
  box-shadow: 0 0 5px hsla(0, 0%, 0%, 0.1), 0 2px 3px hsla(0, 0%, 0%, 0.1);
  border-left: 0.5rem solid hsl(0, 0%, 100%);
  /* by default hide the element from sight and include a transition for the chosen properties */
  transform: translateX(100%);
  opacity: 0;
  visibility: hidden;
  transition-property: transform, opacity, visibility;
  transition-duration: 0.7s;
  transition-timing-function: cubic-bezier(0.445, 0.05, 0.55, 0.95);
}
.notification__message h1 {
  font-size: 1.1rem;
  font-weight: 500;
  text-transform: capitalize;
}
.notification__message p {
  max-width: 320px;
  font-size: 0.8rem;
  grid-column: 1/-1;
}
.notification__message button {
  background: none;
  border: none;
  color: inherit;
  width: 20px;
  height: 20px;
  grid-column: 2/3;
  grid-row: 1/2;
  align-self: center;
}
.notification__message button svg {
  display: block;
  width: 100%;
  height: 100%;
}
 
/* when the .notification container has a class of .received transition the message into view */
.notification.received .notification__message {
  transform: translateX(0%);
  opacity: 1;
  visibility: visible;
}
/* change the border color according to the different modifiers
! for each modifier specify also an svg icon in the background, to highlight the message
*/
.message--info {
  border-left-color: #90dee9;
  background: url('data:image/svg+xml;utf8,'),
    hsl(0, 0%, 100%);
  background-repeat: no-repeat;
  background-size: 35px;
  background-position: 100% 100%;
}
.message--success {
  border-left-color: hsl(120, 67%, 74%);
  background: url('data:image/svg+xml;utf8,'),
    hsl(0, 0%, 100%);
  background-repeat: no-repeat;
  background-size: 35px;
  background-position: 100% 100%;
}
.message--warning {
  border-left-color: hsl(54, 67%, 74%);
  background: url('data:image/svg+xml;utf8,'),
    hsl(0, 0%, 100%);
  background-repeat: no-repeat;
  background-size: 35px;
  background-position: 100% 100%;
}
.message--danger {
  border-left-color: hsl(0, 67%, 74%);
  background: url('data:image/svg+xml;utf8,'),
    hsl(0, 0%, 100%);
  background-repeat: no-repeat;
  background-size: 35px;
  background-position: 100% 100%;
}