Cannot change images caption

Hello,

I have a problem with the images caption. It appears a black line on the left of the caption, and the text is left aligned. So I want to erase the black line and to change the alignment and the color and font of the caption. How can I do that? I apologise for my misunderstanding, I am new on this environment. I write down what appears on my css theme style:

/* CAPTION
—————– */
p img,
.wp-caption {
margin-top: 8px;
}

.wp-caption {
background: whitesmoke;
max-width: 96%;
padding: 15px 10px 10px;
-webkit-transition: all 0.15s ease-in-out;
-webkit-transition-delay: 0s;
-moz-transition: all 0.15s ease-in-out 0s;
-o-transition: all 0.15s ease-in-out 0s;
transition: all 0.15s ease-in-out 0s;
margin-bottom: 10px;
}
.wp-caption img {
display: block;
margin: 0 auto;
max-width: 98%;
}
.wp-caption:hover {
background: #eeeeee;
}
.wp-caption .wp-caption-text {
color: #333333;
font-size: 12px;
margin: 0;
padding: 15px 0 5px 40px;
position: relative;
}
.wp-caption .wp-caption-text:before {
content: ‘\2014’;
font-style: normal;
margin-right: 5px;
position: absolute;
left: 10px;
top: 15px;
}

Thanks for all.