.advent-calendar__day {
position: relative;
float: left;
width: 15%;
height: 100px;
margin: 10px 10px 0 0;
}
.advent-calendar__day--future {
background-size: contain;
background-repeat: no-repeat;
}
.advent-calendar__day-number {
position: absolute;
bottom: 0;
right: 0;
padding: 0.1em;
font-size: 2.5em;
line-height: 1;
background-color: white;
}