Wide and Full-width Gutenberg block options

functions.php

<?php
// Register support for Gutenberg wide images in your theme
function mytheme_setup() {
  add_theme_support( 'align-wide' );
}
add_action( 'after_setup_theme', 'mytheme_setup' );

style.css

/* This is a starting point. Customize for your theme */
.entry-content .alignwide {
    margin-left  : -80px;
    margin-right : -80px;
}
.entry-content .alignfull {
    margin-left  : calc( -100vw / 2 + 100% / 2 );
    margin-right : calc( -100vw / 2 + 100% / 2 );
    max-width    : 100vw;
}
.alignfull img {
    width: 100vw;
}