Alter The Image Width In The 1 Column Left Image & Right Content Grid

/* edit globally (can also be added in the VC custom CSS to target a specific page only) */
body .entries.left-thumbs .entry .entry-media { width: 20% }
body .entries.left-thumbs .entry .entry-details { width: 76% }

/* target specific grid */
.my-custom-class .entries.left-thumbs .entry .entry-media { width: 20% }
.my-custom-class .entry .entry-details { width: 76% }