.icon.add{ position: relative; }
.icon.add::before,
.icon.add::after{
    content: "";
    position: absolute;
    left: 50%; top: 50%;
    width: 60%;
    height: 2px;
    background: currentColor;
    transform: translate(-50%, -50%);
    border-radius: 999px;
}
.icon.add::after{
    transform: translate(-50%, -50%) rotate(90deg);
}