Preview:
.input-container.outline { 
    background-image: linear-gradient(to right, var(--clr), var(--clr)),
                      linear-gradient(to bottom, var(--clr), var(--clr)),
                      linear-gradient(to right, var(--clr), var(--clr)),
                      linear-gradient(to bottom, var(--clr), var(--clr));
    background-size:  100% 2px, 2px 100%, 100% 2px, 2px 100%;
    background-position:  0 0, 100% 0%, 100% 100%, 0 100%; 
    background-repeat: no-repeat;
}
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