style.css

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

:root {
  --text-fade-time: 0.5s;
  --container-shrink-time: 1s;
}

* {
  box-sizing: border-box;
}

body {
  font-family: 'Muli', sans-serif;
  background-color: #f0f0f0;
}

h1 {
  margin: 50px 0 30px;
  text-align: center;
}

.faq-container {
  max-width: 600px;
  margin: 0 auto;
}

.faq {
  background-color: transparent;
  border: 1px solid #9fa4a8;
  border-radius: 10px;
  margin: 20px 0;
  padding: 30px;
  position: relative;
  overflow: hidden;
  transition: 0.3s ease-in-out;
  transition: background-color var(--container-shrink-time) ease-in-out var(--text-fade-time),
    box-shadow var(--container-shrink-time) ease-in-out var(--text-fade-time);
}

.faq.active {
  background-color: #fff;
  box-shadow: 0 3px 6px rgba(0, 0, 0, 0.1), 0 3px 6px rgba(0, 0, 0, 0.1);
  transition: background-color var(--container-shrink-time) ease-in-out, box-shadow var(--container-shrink-time) ease-in-out;
}

.faq::before,
.faq::after {
  content: '\f075';
  font-family: 'Font Awesome 5 Free';
  color: #2acc71;
  font-size: 7rem;
  position: absolute;
  opacity: 0;
  top: 20px;
  left: 20px;
  z-index: 0;
  transition: opacity var(--container-shrink-time) ease-in-out var(--text-fade-time);
}

.faq::before {
  color: #3498db;
  top: -10px;
  left: -30px;
  transform: rotateY(180deg);
}

.faq.active::before,
.faq.active::after {
  opacity: 0.2;
  transition: opacity var(--container-shrink-time) ease-in-out;
}

.faq-title {
  margin: 0 35px 0 0;
}

.faq-text {
  display: block;
  font-size: 0.1px;
  opacity: 0;
  margin: 0;
  padding: 0;
  transition: margin var(--container-shrink-time) ease-in-out var(--text-fade-time), padding var(--container-shrink-time) ease-in-out var(--text-fade-time),
    font-size var(--container-shrink-time) ease-in-out var(--text-fade-time), opacity var(--text-fade-time) ease-in-out;
}

.faq.active .faq-text {
  opacity: 1;
  font-size: inherit;
  margin: 30px 0 0;
  transition: margin var(--container-shrink-time) ease-in-out, padding var(--container-shrink-time) ease-in-out,
    font-size var(--container-shrink-time) ease-in-out, opacity var(--text-fade-time) ease-in-out var(--container-shrink-time);
}

.faq-toggle {
  background-color: transparent;
  border: 0;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  padding: 0;
  position: absolute;
  top: 30px;
  right: 30px;
  height: 30px;
  width: 30px;
}

.faq-toggle:focus {
  outline: 0;
}

.faq-toggle .fa-times {
  display: none;
}

.faq.active .faq-toggle .fa-times {
  display: block;
}

.faq-toggle .fa-chevron-down {
  display: block;
}

.faq.active .faq-toggle .fa-chevron-down {
  display: none;
}

.faq.active .faq-toggle {
  background-color: #9fa4a8;
  color: #fff;
}