* {
            margin: 0;
            padding: 0;
        }
        div:nth-child(1) {
            background: red;
        }
        div:nth-child(2) {
            background: green;
        }
        div:nth-child(3) {
            background: blue;
        }
    </style>

$(document).ready(function() {
            $("div").eq(0).css({padding: 10, "text-align": "center"});
            $("div").css("width", function(index) {
                return index * 100 + 100; // 100, 200, 300
            });
        });