style.css

body {
  font-family: "Montserrat", sans-serif;
  font-size: 16px;
  color: #2c2c2c;
}
body a {
  color: inherit;
  text-decoration: none;
}

.header {
  max-width: 500px;
  margin: 50px auto;
  text-align: center;
}

.header__btns {
  display: flex;
  justify-content: center;
  gap: 15px;
}

.header__btn {
  transition-property: all;
  transition-duration: 0.2s;
  transition-timing-function: linear;
  transition-delay: 0s;
  padding: 10px 20px;
  margin-right: 10px;
  background-color: #fff;
  border: 1px solid #2c2c2c;
  border-radius: 3px;
  cursor: pointer;
  outline: none;
}
.header__btn:last-child {
  margin-right: 0;
}
.header__btn:hover, .header__btn.js-active {
  color: #fff;
  background-color: #2c2c2c;
}

.header__title {
  margin-bottom: 10px;
  font-weight: 500;
}

.header__subtitle {
  margin-bottom: 30px;
  font-size: 20px;
}

.content {
  width: 700px;
  max-width: 95%;
  margin: auto;
}

.effect {
  margin-bottom: 50px;
}

.effect__title {
  text-align: center;
}

.effect__cell {
  display: flex;
  justify-content: center;
  margin-bottom: 20px;
}
.effect__cell:last-child {
  margin-bottom: 0;
}

/******* COMMON NOTIFICATION STYLES *******/
.notification {
  display: flex;
  max-width: 700px;
  padding: 20px;
  border-radius: 5px;
  font-family: "Open Sans", sans-serif;
  box-sizing: border-box;
}
.notification:before {
  display: inline-flex;
  flex-shrink: 0;
  content: "";
  background-repeat: no-repeat;
  background-position: 0 0;
  background-size: contain;
}

.notification--elevation {
  box-shadow: rgba(0, 0, 0, 0.2) 0px 5px 5px -3px, rgba(0, 0, 0, 0.14) 0px 8px 10px 1px, rgba(0, 0, 0, 0.12) 0px 3px 14px 2px;
}

.notification__btn {
  border: none;
  background-image: none;
  background-color: transparent;
  cursor: pointer;
}

.notification__btn--close {
  width: 15px;
  height: 15px;
  flex-shrink: 0;
  background-size: 100% 100%;
  background-repeat: no-repeat;
  text-indent: -99999px;
}

.notification__title {
  margin-top: 0;
  margin-bottom: 10px;
}

.notification__content p {
  margin-top: 0;
  line-height: 1.5;
}
.notification__content p:last-child {
  margin-bottom: 0;
}
.notification__content a {
  text-decoration: underline;
}

/******* NOTIFICATIONS #1 *******/
.notification1 {
  gap: 20px;
}
.notification1:before {
  display: inline-flex;
  width: 30px;
  height: 30px;
  flex-shrink: 0;
  content: "";
  background-size: contain;
}
@media (min-width: 500px) {
  .notification1:before {
    width: 40px;
    height: 40px;
  }
}

.notification1--success:before {
  background-image: url("https://assets.codepen.io/3341051/check.svg");
}
.notification1--success a {
  color: #006600;
}

.notification1--warning:before {
  background-image: url("https://assets.codepen.io/3341051/warning.svg");
}
.notification1--warning a {
  color: #d26a0f;
}

.notification1--danger:before {
  background-image: url("https://assets.codepen.io/3341051/danger.svg");
}
.notification1--danger a {
  color: #bb0202;
}

.notification1__title--success {
  color: #008e00;
}

.notification1__title--warning {
  color: #f18c33;
}

.notification1__title--danger {
  color: #fd0d0d;
}

@media (min-width: 500px) {
  .notification1__content {
    margin-right: 30px;
  }
}

.notification1__close {
  background-image: url("https://assets.codepen.io/3341051/cancel.svg");
}

/******* NOTIFICATIONS #2 *******/
.notification2 {
  flex-wrap: wrap;
  justify-content: center;
  border: 2px solid;
}
@media (min-width: 500px) {
  .notification2 {
    flex-wrap: nowrap;
    justify-content: flex-start;
    gap: 20px;
  }
}
.notification2:before {
  display: inline-flex;
  width: 35px;
  height: 35px;
  flex-shrink: 0;
  content: "";
  background-color: #fff;
  background-position: 50%;
  border-radius: 50%;
  border: 10px solid;
}

.notification2--success {
  background-color: #d6ffd6;
  border-color: #008e00;
}
.notification2--success:before {
  background-size: 75%;
  background-image: url(https://assets.codepen.io/3341051/check2.svg);
  border-color: #008e00;
}

.notification2--warning {
  background-color: #fcdfc5;
  border-color: #f18c33;
}
.notification2--warning:before {
  background-size: 70%;
  background-image: url(https://assets.codepen.io/3341051/warning2.svg);
  border-color: #f18c33;
}

.notification2--danger {
  background-color: #ffd6d6;
  border-color: #fd0d0d;
}
.notification2--danger:before {
  background-size: 55%;
  background-image: url(https://assets.codepen.io/3341051/danger2.svg);
  border-color: #fd0d0d;
}

.notification2__btn-bar {
  display: inline-flex;
  order: -1;
  width: 100%;
  justify-content: flex-end;
}
@media (min-width: 500px) {
  .notification2__btn-bar {
    order: 0;
    width: auto;
  }
}

.notification2__close {
  background-image: url("https://assets.codepen.io/3341051/cancel2.svg");
}

.notification2__content {
  margin-top: 20px;
  text-align: center;
}
@media (min-width: 500px) {
  .notification2__content {
    margin-top: 0;
    margin-right: 30px;
    text-align: left;
  }
}

/******* NOTIFICATIONS #3 *******/
.notification3 {
  flex-wrap: wrap;
  justify-content: center;
  border-top: 7px solid;
  border-top-left-radius: 0;
  border-top-right-radius: 0;
  border-bottom-left-radius: 5px;
}
@media (min-width: 500px) {
  .notification3 {
    flex-wrap: nowrap;
    justify-content: flex-start;
    gap: 20px;
    border-top: 0;
    border-left: 7px solid;
    border-top-right-radius: 5px;
    border-bottom-left-radius: 0;
  }
}
.notification3:before {
  width: 60px;
  height: 60px;
  align-self: center;
  flex-shrink: 0;
  content: "";
  border-radius: 50%;
  background-position: 50%;
}

.notification3--success {
  background-color: #d6ffd6;
  border-color: #008e00;
}
.notification3--success:before {
  background-color: #008e00;
  background-size: 60%;
  background-image: url(https://assets.codepen.io/3341051/check3.svg);
}

.notification3--warning {
  background-color: #fcdfc5;
  border-color: #f18c33;
}
.notification3--warning:before {
  background-color: #f18c33;
  background-size: 60%;
  background-image: url(https://assets.codepen.io/3341051/warning3.svg);
}

.notification3--danger {
  background-color: #ffd6d6;
  border-color: #fd0d0d;
}
.notification3--danger:before {
  background-color: #fd0d0d;
  background-size: 50%;
  background-image: url(https://assets.codepen.io/3341051/danger3.svg);
}

.notification3__content {
  margin-top: 20px;
  text-align: center;
}
@media (min-width: 500px) {
  .notification3__content {
    margin-top: 0;
    margin-right: 30px;
    text-align: left;
  }
}

.notification3__btn-bar {
  display: inline-flex;
  order: -1;
  width: 100%;
  justify-content: flex-end;
}
@media (min-width: 500px) {
  .notification3__btn-bar {
    order: 0;
    width: auto;
  }
}

.notification3__close {
  background-image: url("https://assets.codepen.io/3341051/cancel2.svg");
}

/******* NOTIFICATIONS #4 *******/
.notification4 {
  position: relative;
  padding: 0 20px 0 0;
  flex-wrap: wrap;
}
@media (min-width: 500px) {
  .notification4 {
    flex-wrap: nowrap;
    gap: 20px;
  }
}
.notification4:before {
  position: absolute;
  top: 0;
  left: 0;
  width: 60px;
  height: 100%;
  flex-shrink: 0;
  content: "";
  background-position: 50%;
}
@media (min-width: 500px) {
  .notification4:before {
    width: 80px;
  }
}

.notification4--success:before {
  background-color: #008e00;
  background-size: 35px auto;
  background-image: url(https://assets.codepen.io/3341051/check3.svg);
}
@media (min-width: 500px) {
  .notification4--success:before {
    background-size: 40px auto;
  }
}
.notification4--success a {
  color: #006600;
}

.notification4--warning:before {
  background-color: #f18c33;
  background-size: 35px auto;
  background-image: url(https://assets.codepen.io/3341051/warning3.svg);
}
@media (min-width: 500px) {
  .notification4--warning:before {
    background-size: 40px auto;
  }
}
.notification4--warning a {
  color: #d26a0f;
}

.notification4--danger:before {
  background-color: #fd0d0d;
  background-size: 30px auto;
  background-image: url(https://assets.codepen.io/3341051/danger3.svg);
}
@media (min-width: 500px) {
  .notification4--danger:before {
    background-size: 35px auto;
  }
}
.notification4--danger a {
  color: #bb0202;
}

.notification4__title--success {
  color: #008e00;
}

.notification4__title--warning {
  color: #f18c33;
}

.notification4__title--danger {
  color: #fd0d0d;
}

.notification4__content {
  padding: 20px 0;
  margin-left: 80px;
}
@media (min-width: 500px) {
  .notification4__content {
    margin-left: 100px;
    margin-right: 30px;
  }
}

.notification4__btn-bar {
  display: inline-flex;
  padding-top: 20px;
  width: 100%;
  order: -1;
  justify-content: flex-end;
}
@media (min-width: 500px) {
  .notification4__btn-bar {
    width: auto;
    order: 0;
  }
}

.notification4__close {
  background-image: url("https://assets.codepen.io/3341051/cancel.svg");
}