How to override CSSin Wordpress - php

Question

I'm trying to create a Wordpress child theme, but I can't seem to get it to override styles in the parent theme.
functions.php
<?php
if ( ! function_exists( 'my_theme_enqueue_styles' ) ) {
add_action( 'wp_enqueue_scripts', 'my_theme_enqueue_styles' );
function my_theme_enqueue_styles() {
wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
}
}
/**
* WP Enqueue Stylesheets
*/
if ( ! function_exists( 'rev_cust_enqueue_stylesheets' ) ) {
add_action( 'wp_enqueue_scripts', 'rev_cust_enqueue_stylesheets' );
function rev_cust_enqueue_stylesheets() {
wp_enqueue_style( 'rev-main', get_template_directory_uri() . '/layout/css/rev_main.css', array(), '', 'all' );
}
}
?>
rev_main.css
#header .top-header .header-navigation ul li {
margin-left: 40px;
line-height: 1.375;
font-weight: normal !important;
font-size: 1px;
color: #fff;
text-transform: uppercase;
position: relative;
float: left;
}
Why isn't my style class not being picked?
Thank you all in advance.
UPDATE
I don't think the css file even gets picked up,
I have the child theme enabled.

Answer 1

The problem was at:
get_template_directory_uri()
in:
/**
* WP Enqueue Stylesheets
*/
if ( ! function_exists( 'rev_cust_enqueue_stylesheets' ) ) {
add_action( 'wp_enqueue_scripts', 'rev_cust_enqueue_stylesheets' );
function rev_cust_enqueue_stylesheets() {
wp_enqueue_style( 'rev-main', get_template_directory_uri() . '/layout/css/rev_main.css', array(), '', 'all' );
}
}
?>
This points to the parent theme, instead of the child theme.
It should be get_stylesheet_directory_uri as follows:
function rev_cust_enqueue_stylesheets() {
wp_enqueue_style( 'rev-main', get_stylesheet_directory_uri() . '/layout/css/rev_main.css', array(), '', 'all' );
}