style.css

html, body {
  height: 100%;
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
  position: static;
}

.flex-container {
  display: flex;
  align-items: center;
  justify-content: center;
}

.flex-button {
  display: flex;
  align-items: center;
  justify-content: center;
  outline: none;
}

blockquote {
  min-height: 5em;
  padding: 1em 4em;
  font: 1em/150% sans-serif;
  position: relative;
  background-color: lightblue;
  border-radius: 10px;
  width: 100%;

  transition: opacity 1s ease-out;
  opacity: 1;
  z-index: 1;
}

blockquote::before,
blockquote::after {
  position: absolute;
  height: 3rem;
  font: 6rem/100% Georgia, "Times New Roman", Times, serif;
}

blockquote::before {
  content: "“";
  top: 0.3rem;
  left: 0.9rem;
}

blockquote::after {
  content: "”";
  bottom: 0.3rem;
  right: 0.8rem;
}

blockquote i {
  display: block;
  font-size: 0.8em;
  margin-top: 1rem;
  text-align: right;
}

.btn {
  border: none;
  background-color: white;
  font-size: 2rem;
  outline: none;
  cursor: pointer;
  
}

.btn-rotate {
  border: none;
  background-color: white;
  font-size: 2rem;
  outline: none;
  cursor: pointer;
  
}

@keyframes loading-rotate {
  0% {
    transform: rotate(0);
  }
  100% {
    transform: rotate(360deg);
  }
}

body.loading .btn-rotate:first-child {
  animation: loading-rotate infinite 1s ease-out;
}

body.loading blockquote {
  opacity: .0;
}