A lot of the times a website's <body>
tag will have a class on it like...
<body class="about"> <!-- for the about page -->
or
<body class="home"> <!-- for the homepage -->
and so on. You can do something like this to target it on individual pages:
.button-upload {
float: left; /* It's floated left most the time */
}
.about .button-upload {
float: right; /* Not on the about page, though! */
}