.ui-box {
    border-style: solid;
    border-width: 8px;
    border-image-slice: 30% fill;
    background-clip: padding-box;
    padding: 0;
}

.box-a { border-image-source: url('../Img/UI_Box_A.png'); }
.box-b { border-image-source: url('../Img/UI_Box_B.png'); }
.box-c { border-image-source: url('../Img/UI_Box_C.png'); }
.box-g { 
    border-image-source: url('../Img/UI_Box_G.png');
    border-width: 16px;
    border-image-slice: 33% fill;
}
.box-g:hover { border-image-source: url('../Img/UI_Box_G_Hovered.png'); }