Change border (width, style, color) of Read More button

To change border (width, style, color) of Read More button of Content Views, please use this CSS:

/* Change border of Read More button */
.pt-cv-view .pt-cv-readmore {
    border-width: 3px !important;
    border-style: solid !important;
    border-color: red !important;
}

.pt-cv-view .pt-cv-readmore:hover {
    border-width: 3px !important;
    border-style: solid !important;
    border-color: red !important;
}

You can change values of width, style, color as you want.

Best regards,