nav {
  background-color: rgba(0, 0, 0, 0.614);
  padding: 15px 0;
  text-align: center;
  position: sticky;
  top: 0;
  width: 100%;
  position: relative;
  color: white;
}
#check {
  display: none;
}
#check:checked ~ .content {
  transform: translateY(0);
}
nav .content {
  background: rgb(0, 0, 0);
  position: absolute;
  top: 100%;
  left: 0;
  width: 100%;
  transform: translateY(-200%);
  transition: 0.5s;
}

nav li {
  padding: 5px 0;
}
.card {
  width: 28%;
  background-color: khaki;
  display: inline-block;
  margin: 20px 30px;
}
.text h2 {
  font-family: "Courier New", Courier, monospace;
  letter-spacing: 8px;
}
.card img {
  width: 100%;
}
.text {
  padding: 10px 30px;
}
.text p {
  text-align: center;
}
.text form {
  text-align: center;
}
button {
  padding: 5px 15px;
  display: block;
  margin: 20px auto;
  background-color: aquamarine;
}
.cards {
  background-image: linear-gradient(to right, lightblue, lightgreen);
  padding: 30px;
}
.q {
  color: red;
}
.k {
  color: blue;
}