Class has a dot, element does not.

header {
display: flex;
flex-wrap: wrap;
flex-direction: column;
align-items: center;
justify-content: center;
width: 100%;
}
main {
display: flex;
flex-wrap: wrap;
width: 100%;
margin: 50px 10% 10%;
}
.card {
border: 2px dotted black

}