design has been broken in WordPress child theme [closed]

It seems like all the css files are not laoding, you can check what’s not loading the source code and add that or simply replace your functions.php with the following code for Hestia theme.

<?php
if ( !defined( 'ABSPATH' ) ) exit;

if ( !function_exists( 'hestia_child_parent_css' ) ):
    function hestia_child_parent_css() {
        wp_enqueue_style( 'hestia_child_parent', trailingslashit( get_template_directory_uri() ) . 'style.css', array( 'bootstrap' ) );
    if( is_rtl() ) {
        wp_enqueue_style( 'hestia_child_parent_rtl', trailingslashit( get_template_directory_uri() ) . 'style-rtl.css', array( 'bootstrap' ) );
    }

    }
endif;
add_action( 'wp_enqueue_scripts', 'hestia_child_parent_css', 10 );

/**
 * Import options from the parent theme
 *
 * @since 1.0.0
 */
function hestia_child_get_parent_options() {
    $hestia_mods = get_option( 'theme_mods_hestia' );
    if ( ! empty( $hestia_mods ) ) {
        foreach ( $hestia_mods as $hestia_mod_k => $hestia_mod_v ) {
            set_theme_mod( $hestia_mod_k, $hestia_mod_v );
        }
    }
}
add_action( 'after_switch_theme', 'hestia_child_get_parent_options' );

Source for the snippet: How to create a Child theme for Hestia