styles.css

@import url("https://fonts.googleapis.com/css2?family=Parisienne&display=swap");

:root {
  --lightBlue: #a7b7c0;
  --lightGreen: #808375;
  --mediumGreen: #6f7261;
  --darkGreen: #5e6152;
  --darkerGreen: #494b40;
  --textGreen: #7f8372;
  --almostWhite: #eeebe6;
}

body {
  background: var(--lightBlue);
  color: var(--textGreen);
  font-family: "Parisienne", cursive;
}

.envelope {
  width: 220px;
  margin: 400px auto;
  height: 120px;
  position: relative;
  background: var(--darkerGreen);
  cursor: pointer;
  box-shadow: 0px 4px 6px -3px var(--lightGreen);
}

.top,
.bottom {
  border-left: 110px solid transparent;
  border-right: 110px solid transparent;
  width: 0;
  height: 0;
  position: relative;
}

.top {
  border-bottom: 80px solid var(--lightGreen);
  top: -80px;
  transform-origin: bottom;
  z-index: 3;
  transition: all 0.8s ease;
  transform: rotateX(0deg);
}

.bottom {
  border-bottom: 80px solid var(--darkGreen);
  top: -40px;
  z-index: 4;
}

.left,
.right {
  width: 0;
  height: 0;
  border-top: 60px solid transparent;
  border-bottom: 60px solid transparent;
  top: 0;
  z-index: 4;
}

.left {
  border-left: 110px solid var(--mediumGreen);
  position: absolute;
  left: 0;
}

.right {
  border-right: 110px solid var(--mediumGreen);
  position: absolute;
  right: 0;
}

.back {
  width: 100%;
  height: 100%;
  position: absolute;
  transition: all 1s ease;
  z-index: 3;
  transition-delay: 0.4s;
  top: -100%;
}

.paper {
  width: 90%;
  height: 90%;
  background: var(--almostWhite);
  margin: 6px auto 0;
  transition: all 0.5s ease-out;
  position: absolute;
  left: 50%;
  transform: translate(-50%);
  border-radius: 0px;
  display: flex;
  flex-direction: column;
  box-sizing: border-box;
  overflow: hidden;
}

.envelope.fold .back {
  z-index: 3;
  transition-delay: 0.1s;
  top: 0;
}

.envelope.fold .top {
  transition-delay: 0.6s;
  transform: rotateX(180deg);
  z-index: 6;
}

.envelope.grow .back {
  z-index: 999;
  transform: scale(500%) translateY(20%);
  transition-duration: 2s;
}

.title {
  font-size: 0.6rem;
  margin-bottom: 10px;
  text-align: center;
}

.content {
  font-size: 0.3rem;
  text-align: center;
}

.mb-1 {
  margin-bottom: 8px;
}

.container {
  border: solid 0.5px var(--textGreen);
  display: flex;
  flex-direction: column;
  box-sizing: border-box;
  padding: 10px 15px;
  margin: 5px;
  height: 100%;
}

.flower {
  position: absolute;
  height: 60%;
  width: 60%;
  color: var(--textGreen);
  opacity: 0.1;
  z-index: -1;
  bottom: -30%;
  left: -50px;
}