linking stylesheets and scripts with functions.php

There are no errors in your code shown above and I’ve double checked to see it working correctly in a fresh WP install. It should not be the cause of your errors.

A white screen is usually any error but it’s not printed to the screen.

Take a look at the DEBUG section of the codex to change that. This might need to be dropped into your wp-config.php.

// allow debugging 
defined( 'WP_DEBUG' ) or define( 'WP_DEBUG', true );

// log errors to wp-content/debug.log
defined( 'WP_DEBUG_LOG' ) or define( 'WP_DEBUG_LOG', true );

// show errors on screen
defined( 'WP_DEBUG_DISPLAY' ) or define( 'WP_DEBUG_DISPLAY', true );