When creating your site style sheet(s), try to keep things in a modular fashion. This way when debugging your CSS you can have those modules quarantined for easy inspection.

For Example...........

@charset "UTF-8"
/* CSS Document */

/* =============================================================================

   Reset Styles

   ========================================================================== */

/* =============================================================================

   Layout Styles

   ========================================================================== */


/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Global Page LAYOUT STYLES */

your-code-here {.........}


/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Page Specific LAYOUT STYLES */

/*HOME*/
your-code-here {.........}
/*ABOUT US*/
your-code-here {.........}

/* =============================================================================

   COLOR STYLES

   ========================================================================== */


/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Global Color LAYOUT STYLES */

your-code-here {.........}

/*xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Page Specific Color LAYOUT STYLES */

/*HOME*/
your-code-here {.........}
/*ABOUT US*/
your-code-here {.........}