Change the background color in a twitter bootstrap modal?

To change the color via:

CSS

Put these styles in your stylesheet after the bootstrap styles:

.modal-backdrop {
   background-color: red;
}

Less

Changes the bootstrap-variables to:

@modal-backdrop-bg:           red;

Source

Sass

Changes the bootstrap-variables to:

$modal-backdrop-bg:           red;

Source

Bootstrap-Customizer

Change @modal-backdrop-bg to your desired color:

getbootstrap.com/customize/

You can also remove the backdrop via Javascript or by setting the color to transparent.