Transparent background in post content

http://www.3dsolex.com

the text is now in top and bottom of child css.

I do not expect this to work, I have not seen anyone who has been able to make it work..

I do not understand, how it can be so hellishly difficult to just turn
off the background? Must be thousands who wish this and just give
up..

The side menu seems to manage it…

Theme will not install, “broken theme”

/*
Theme Name: Twenty Fifteen Child
Theme URI: https://wordpress.org/themes/twentyfifteen
Author: the WordPress team
Author URI: https://wordpress.org/
Description: Our 2015 default theme is clean, blog-focused, and designed for clarity. Twenty Fifteen’s simple, straightforward typography is readable on a wide variety of screen sizes, and suitable for multiple languages. We designed it using a mobile-first approach, meaning your content takes center-stage, regardless of whether your visitors arrive by smartphone, tablet, laptop, or desktop computer.
Version: 1.0
License: GNU General Public License v2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
Tags: black, blue, gray, pink, purple, white, yellow, dark, light, two-columns, left-sidebar, fixed-layout, responsive-layout, accessibility-ready, custom-background, custom-colors, custom-header, custom-menu, editor-style, featured-images, microformats, post-formats, rtl-language-support, sticky-post, threaded-comments, translation-ready
Text Domain: twentyfifteen-child

This theme, like WordPress, is licensed under the GPL.
Use it to make something cool, have fun, and share what you’ve learned with others.
*/

Functions.php
<?php
add_action( ‘wp_enqueue_scripts’, ‘theme_enqueue_styles’ );
function theme_enqueue_styles() {
wp_enqueue_style( ‘twentyfifteen’, get_template_directory_uri() . ‘/style.css’ );

}
/**
* Twenty Fifteen functions and definitions
*
* Set up the theme and provides some helper functions, which are used in the
* theme as custom template tags. Others are attached to action and filter

http://www.3dsolex.com
If I activate the childe theme it goes blank.
Here are the top of my files:
/*
Theme Name: Twenty Fifteen Child
Template: twentyfifteen
*/
/**
* Table of Contents
*

and

<?php
add_action( ‘wp_enqueue_scripts’, ‘theme_enqueue_styles’ );
function theme_enqueue_styles() {
wp_enqueue_style( ‘twentyfifteen’, get_template_directory_uri() . ‘/style.css’ );

}

If I activate it, the entire site goes white..

<?php
add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles' );
function theme_enqueue_styles() {
wp_enqueue_style( 'twentyfifteen', get_template_directory_uri() . '/style.css' );

}
/**
 * Twenty Fifteen functions and definitions
 *
 * Set up the theme and provides some helper functions, which are used in

[The rest of the code has been moderated]