Oh I see, to alternate the row colors you can do this:
1) Go to the category blog layout options and put the total amount of articles you want in leading, right now you have it set to 1 leading and 5 or whatever items, make it 0 leading.
2) Put this code in your Custom CSS area:
.items-row:nth-child(even) {background: #CCC}
.items-row:nth-child(odd) {background: #FFF}
OR, you could use this code that creates a gradient for each box:
.items-row {background: #f7e9dc; /* Old browsers */
background: -moz-linear-gradient(top, #f7e9dc 0%, #f2f2f2 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#f7e9dc), color-stop(100%,#f2f2f2)); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top, #f7e9dc 0%,#f2f2f2 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top, #f7e9dc 0%,#f2f2f2 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top, #f7e9dc 0%,#f2f2f2 100%); /* IE10+ */
background: linear-gradient(to bottom, #f7e9dc 0%,#f2f2f2 100%); /* W3C */
filter: progid
XImageTransform.Microsoft.gradient( startColorstr='#f7e9dc', endColorstr='#f2f2f2',GradientType=0 ); /* IE6-9 */
}
If you need to change the gradient you can use this tool:
http://www.colorzilla.com/gradient-editor/