This is not a good solution because all the php, javascript and html code will be output the same. It raises lots of issues:

- malicious users could change your style settings and share the content the same (and maybe your pages are not ready to be shared)

- the page is heavier than expected

Moreover it's not recommended to change the template files to apply a style to a page. It is sufficient to add this code to your style.css file:

body.page .yourdivclass { /* these rules only apply for pages */ }