Block Quote in Post Issue

When I use a block quote in posts the text is encased in a grey box with a thin red line on the left hand side. Is there any way that this can be changed and if so where?


the code is placed on styles.css but its recommended if you change it using simple custom css plugin:

and here is the css code that you might to edit:

.hentry blockquote {
    border-left: 3px solid #d65050;

.hentry blockquote {
    background-color: #333;
    color: #fff;
    font-size: 16px;
    font-style: italic;
    line-height: 23px;
    margin-bottom: 30px;
    padding: 30px 35px;
    position: relative;