Using two CSS classes on one element [duplicate]

Answer 1

Instead of using multiple CSS classes, to address your underlying problem you can use the :focus pseudo-selector:

input[type="text"] {
   border: 1px solid grey;
   width: 40%;
   height: 30px;
   border-radius: 0;
}
input[type="text"]:focus {
   border: 1px solid #5acdff;
}