Add this code to the Custom CSS field on the Settings tab of your Blog widget’s settings:
/* Title */
[class*="card-content__CardContentTitle"] {
color: #f1f;
}
/* Excerpt */
[class*="card-content__CardContentTitle"]+div {
color: brown;
}
/* Date Author */
[class*="card-content__CardContentTitle"]+div+div {
color: gold;
}