Editing mutliple features of a theme

I am trying to edit multiple features of a child theme. I have been using the preview of my webpage to determine the changes I want to make and editing the code in responsive design mode. I then copy the changes into the theme’s stylesheet. I have found that the first change I entered was successful but subsequent changes haven’t been, and then the final one in a sequence of four was successful. I’m not sure whether I’m trying to edit features that can’t be changed or if I’ve just missed something obvious in the coding. Also, is there an easier way to apply changes than what I am currently doing?

I’m using a child theme based on ‘Mantra’ and the code I’ve entered is as follows:

[ Moderator note: please wrap code in backticks or use the code button. ]

/*
Theme Name: Chris's Theme
Description: Child theme for Mantra Theme
Author: Chris Huston
Template: mantra
*/

@import url("../mantra/style.css");

#access {
    display: block;
    float: left;
    margin: 0px auto 0px;
}
#front-text2 h1 {
    font-size: 28px;
    line-height: 28px;
    margin-top: 0px;
    margin-bottom: 0px;
}
#frontpage blockquote {
    width: 88%;
    max-width: 88% !important;
    margin-bottom: 20px;
    font-size: 10px;
    line-height: 22px;
    color: rgb(68, 68, 68);
}
blockquote {
    border: 1px solid rgb(238, 238, 238);
    padding: 5px;
    display: block;
    background-color: rgb(250, 250, 250);
    font-style: italic;
    max-width: 90% !important;
    margin: 0px auto;
    clear: both;
    float: none;
    color: rgb(153, 153, 153);
    border-radius: 5px 5px 5px 5px;
    box-shadow: 0px 0px 3px rgb(255, 255, 255) inset;
}