How to Remove Fluid CSS in WordPress
- 1). Load your blog in a browser and right-click to view the source code. Find the tags that enclose each column of the blog, such as "<div id='header'>" or "<div class='sidebar'>". In Web design, a header is typically a full-width column above one, two or three columns in the middle of the page, followed by a footer. You need the ID or class name of each.
- 2). Log in to WordPress and navigate to "Appearance" from the left sidebar. Click the "Editor" link to load the "Edit Themes" screen. The file you need -- style.css -- will load automatically.
- 3). Go through the CSS code of your theme and find the style rules that target each of your columns:
#header {
width: 100%;
}
#content {
width: 65%;
}
#sidebar {
width: 35%;
} - 4). Figure out from the percentage values how wide you need to make each column in pixels. Replace each percentage value with a pixel value, for example:
#header {
width: 960px;
}
#content {
width: 624px;
}
#sidebar {
width: 336px;
}
Update the file when you finish making your changes.
Source...