Use Divi builder on WooCommerce single product pages.

divi-and-woo-single-product.css

/**************************************************/
/*** MAIN CODE TO MAKE SINGLE PRODUCT FULLWIDTH ***/
/**************************************************/
.woocommerce .woocommerce-breadcrumb {
    display: none; /* hides Woo breadcrumbs */
}
.single-product .clearfix {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}
.single-product .et_pb_section .clearfix, .single-product #main-footer .clearfix, .single-product .container.et_menu_container {
    display: block; 
}
.single-product #main-content .container {
    overflow: hidden;
    background: #f0f0f0; /* this color appears behind the default add to cart section */
    padding-top: 0 !important;
    width: 100% !important; /* makes it a fullwidth page */
    max-width: 100% !important; 
}
.single-product #main-content .et_pb_row,
.single-product #tab-description.woocommerce-Tabs-panel .et_pb_row, 
.single-product #tab-description.woocommerce-Tabs-panel .et_pb_row.et_pb_row_fullwidth, 
.single-product #tab-description.woocommerce-Tabs-panel .et_pb_specialty_fullwidth>.et_pb_row {
    width: 100% !important; /* makes content in tabs fullwidth */
    max-width: 100% !important;
}
 body.woocommerce.single-product #content-area div.product .woocommerce-tabs ul.tabs, 
 body.woocommerce.single-product div.product .woocommerce-tabs ul.tabs,
 .single-product #tab-description.woocommerce-Tabs-panel h2 {
     display: none; /* hide description tab and default description h2 since we're adding in manually */
}
.single-product .et_pb_section h2 {
    display: block !important; /* makes all builder h2s visible because we're hiding them above (it's not possible to be more specific above and :not() insn't an option since it only works with simple selectors */
}
.woocommerce.single-product .woocommerce-tabs {
    border: 0;
}
.single-product .woocommerce-tabs .panel {
    padding: 0 !important;
}
.woocommerce.single-product div.product .woocommerce-tabs ul.tabs:before {
    border-bottom-color: transparent;
}
.single-product.woocommerce div.product {
    display: flex;
    flex-direction: column;
}
.single-product div.woocommerce-tabs.wc-tabs-wrapper {
    order: -1; /* moves default tabs section to top */
    margin: 0;
}

/******************************************/
/*** POST TITLE H1 / TOP FEATURED IMAGE ***/
/******************************************/
.single-product .et_pb_post_title.et_pb_featured_bg {
    padding: 24% 8% 0 !important;
}
.woocommerce.single-product .et_pb_post_title.et_pb_featured_bg .et_pb_title_container {
    padding: 0 !important;
    text-align: center;
}
.single-product .et_pb_title_container h1 {
    color: #f0f0f0 !important;
    font-size: 3.3em !important;
    padding: .5em .7em;
    background: rgba(0,0,0,0.7); /* background color of h1 */
    display: inline-block;
}
@media only screen and (max-width: 767px) {
    .single-product .et_pb_post_title.et_pb_featured_bg {
        padding-top: 50% !important;
   }
    .single-product .et_pb_title_container h1 {
        font-size: 2em !important;
   }
}
@media only screen and (min-width: 768px) and (max-width: 1200px) {
    .single-product .et_pb_title_container h1 {
        font-size: 2.5em !important;
   }
}
/************************************/
/*** TESTIMONIAL / INFOBOX MODULE ***/
/************************************/
.woocommerce.single-product .et_pb_testimonial {
    padding: 12% 10% 12% 0 !important;
    display: flex;
    flex-direction: row;
}
.woocommerce.single-product .et_pb_testimonial_meta {
    font-size: 15px;
    font-style: italic;
}
.woocommerce.single-product .et_pb_testimonial:before {
    content: "\7b" !important; /* changes quotes to icon without the circle just cause I like it better lol, you can use ETs icon font library to change it to something else https://www.elegantthemes.com/blog/resources/elegant-icon-font */
    top: 5% !important;
    left: 150px !important;
    background: transparent !important;
    font-size: 80px !important;
}
.woocommerce.single-product .et_pb_testimonial_portrait {
    min-width: 150px !important; /* image width */
    min-height: 300px; /* image height */
    margin-left: -30px !important;
    margin-right: 0 !important;
    border-radius: 35px !important; /* rounded corners */
}
.woocommerce.single-product .et_pb_testimonial_portrait:before {
    border-radius: 35px !important; /* makes inner shadow match image */
    -webkit-box-shadow: inset 0 0 8px rgba(0,0,0,.3); 
    -moz-box-shadow: inset 0 0 8px rgba(0,0,0,.3);
    box-shadow: inset 0 0 8px rgba(0,0,0,.3);
}
.woocommerce.single-product .et_pb_testimonial_description {
    margin-left: 2em !important;
}
@media only screen and (max-width: 480px) {
    .woocommerce.single-product .et_pb_testimonial {
        padding: 16% 10% 16% 0 !important;
   }
    .woocommerce.single-product .et_pb_testimonial:before {
        top: 0 !important;
   }
    .woocommerce.single-product .et_pb_testimonial_description {
        font-size: .9em;
   }
}
/***********************/
/*** GALLERY MODULES ***/
/***********************/
.woocommerce.single-product .et_pb_gallery_grid img {
    min-width: 100%;
}
.single-product .et_pb_gallery .et_pb_gallery_items {
    display: flex; /* images will stay on the same line on all screen sizes so I'd suggest max 5 per module, or remove this */
    flex-direction: row; /* flex column is set on the entire product so this is needed */
}
.single-product .et_pb_gallery {
    margin-bottom: 0 !important;
}
.single-product .et_pb_grid_item {
    width: auto;
    margin: 4px !important; /* this is the space around images that creates the gap */
    flex: 1;
    -webkit-animation: none !important;
    -moz-animation: none !important;
    animation: none !important;
}
/******************/
/*** TYPOGRAPHY ***/
/******************/
.single-product h2 {
    padding-bottom: 0;
}
/*******************************/
/*** CUSTOM COLORED DIVIDERS ***/
/*******************************/
.single-product hr { /* I'm just customizing the horizontal rule since they're easy to add in the editor, you can replace with pseudos or divider modules or whatever method you prefer */
    border-bottom-width: 0;
    border-style: solid;
    border-top-width: 8px; /* change this to make the accent line thicker */
    max-width: 60px;
    border-color: #BC741C; /* custom divider color */
    margin-top: 15px;
    margin-bottom: 15px;
}
.left-hr hr {
    margin-left: 0; /* if you have left align text with a divider add this class, default is centered */
}
.woocommerce.single-product .et_pb_testimonial_author:before { /* custom testimonial divider */
    content: "";
    position: absolute;
    bottom: 20%;
    left: -70px;
    background: #BC741C; 
    width: 60px; /* divider width */
    height: 8px; /* divider thickness */
}
/**********************************/
/*** INTRO BOX UNDER POST TITLE ***/
/**********************************/
.intro-cta .add_to_cart_inline a.button {
    display: none; /* I'm using a Woo shortcode to add the price dynamically but the button needs to be hidden as it will loop to current page */
}
.intro-cta .add_to_cart_inline { /* price styling */
    padding: 0 !important;
    margin-top: -15px;
    border: 0 !important;
    text-align: center;
    font-size: 30px;
    font-weight: 700;
}
@media only screen and (max-width: 980px) {
    .intro-cta {
        margin-left: 30px;
        margin-right: 30px;
   }
}
/************************************************************************/
/*** DEFAULT SUMMARY BOX (FEATURED IMAGE / DESCRIPTION / ADD TO CART) ***/
/************************************************************************/
.woocommerce.single-product .entry-summary .entry-title {
    display: none; /* hide default h1 because we're adding an h1 with the post title module */
}
.woocommerce.single-product div.product div.images.woocommerce-product-gallery {
    margin-top: 10%;
    margin-bottom: 0;
}
.woocommerce.single-product div.product.sale div.images.woocommerce-product-gallery {
    margin-top: 6%; 
}
.single-product .entry-summary p.price {
    margin-top: .5em;
    margin-bottom: .5em;
}
.single-product .entry-summary p.price span {
    font-size: 36px !important;
    font-weight: 700;
}
.single-product .entry-summary .product_meta {
    display: none; /* hide sku and category - optional */
}
.woocommerce.single-product div.product form.cart .variations td select {
    background: #fff; /* dropdown color */
    font-size: 18px;
    font-weight: 500;
    height: 33px;
}
.single-product .entry-summary { /* default description box */
    text-align: center;
    padding: 3% 6% 6%;
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-bottom: 0;
}
.woocommerce.single-product div.product form.cart div.quantity { /* quantity box */
    width: 100px !important;
    margin-right: 0 !important;
}
.woocommerce.single-product .quantity input.qty { /* quantity box */
    border-radius: 0;
    border: 2px solid #222 !important; 
    /* height: 52px; add this and tweak if your quantity box is shorter than your button */
    color: #222 !important;
    background: rgba(255,255,255,0.8) !important;
}
.woocommerce.single-product form.cart .button { /* default add to cart button */
    float: none !important;
    font-size: 1.1em;
}
.woocommerce.single-product button.button.alt.disabled {
    background: #999; /* replaces Woo purple when no selection has been made on variable products */
}
.woocommerce.single-product div.product form.cart {
    display: flex;
}
.woocommerce.single-product div.product form.variations_form.cart, .woocommerce.single-product div.product form.cart .variations tr {
    display: flex;
    flex-direction: column !important;
}
.woocommerce.single-product div.product form.cart .variations td {
    font-size: 18px;
    padding-right: 0 !important;
    margin: auto;
}
.woocommerce.single-product div.product div.images .flex-control-thumbs {
    margin-top: 2%;
    }
.woocommerce div.product div.images .flex-control-thumbs li { /* these three change the gap between small default thumbnails */
    width: 23.5%; 
    margin-right: 2%;
    margin-bottom: 2%;
}
.woocommerce.single-product .pswp__caption__center, .woocommerce.single-product .mfp-title {
    display: none; /* hide titles of lightbox images - optional */
}
.woocommerce.single-product div.product form.cart .variations {
    margin-bottom: 0;
}
.woocommerce-variation-price {
    height: 46px;
    font-size: 24px;
}
.single-product #left-area {
    padding-bottom: 0;
}
@media only screen and (max-width: 768px) {
    .woocommerce.single-product div.product div.images.woocommerce-product-gallery {
        margin-top: 10%;
   }
    .woocommerce.single-product div.product div.images.woocommerce-product-gallery {
        padding-left: 6%;
        padding-right: 6%;
        box-shadow: none !important;
   }
   .woocommerce.single-product div.product div.images .woocommerce-product-gallery__trigger {
        right: 1.5em; /* nudge magnify icon for mobile and tablet */
    }
}
@media only screen and (min-width: 769px) and (max-width: 1200px) {
    .woocommerce div.product div.images {
        width: 60%;
   }
    .single-product .entry-summary {
        width: 80% !important;
   }
}
@media only screen and (min-width: 1281px) {
    .woocommerce.single-product div.product div.images .flex-control-thumbs {
        margin-left: auto;
        margin-right: auto;
        max-width: 70%;
        padding-bottom: 0 !important;
   }
}
/**************************/
/*** ERRORS AND NOTICES ***/
/**************************/
.single-product .woocommerce-error, .single-product .woocommerce-info, .single-product .woocommerce-message {
    padding: 1em 2em !important; /* ex: banner at top after you add something to the cart */
    margin-bottom: 0;
}
/************************/
/*** RELATED PRODUCTS ***/
/************************/
.single-product .related.products {
    background: #fff; /* related section background color */
    width: 100%; /* make fullwidth */
    padding-top: 8%;
    padding-bottom: 5%;
    margin: 0 auto;
    text-align: center;
}
.woocommerce.single-product .products ul, .woocommerce.single-product ul.products {
    margin: 0 14% 1em; /* adds space around related items since the section is fullwidth */
    display: flex;
}
.woocommerce.single-product ul.products li.product .woocommerce-loop-product__title { /* related section heading */
    font-size: 27px !important;
    text-align: center;
}
.single-product .related h2:after { /* add custom divider to related heading to match others */
    content: "";
    position: absolute;
    margin-top: 55px;
    left: 50%;
    transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    -webkit-transform: translate(-50%, -50%);
    background: #BC741C;
    width: 60px;
    height: 8px;
}
.single-product .related h2 { /* related products titles */
    font-size: 36px !important;
    text-align: center;
    text-transform: capitalize; /* it really bugs me that Products isn't capitalized lol - optional */
    margin-bottom: 50px;
}
.single-product .woocommerce-loop-product__title:after {
    content: none !important; /* to not apply decorative line to related product h2, we can't use :not() here */
}
.woocommerce ul.products li.product .star-rating { /* center stars if ratings are enabled */
    margin-left: auto !important;
    margin-right: auto !important;
}
.woocommerce.single-product ul.products li.product .price, .woocommerce.single-product ul.products li.product .price del, .woocommerce.single-product ul.products li.product .price ins {
    font-size: 22px;
    font-weight: 500;
}
.woocommerce.single-product ul.products li.product .price {
    color: #00adad !important;
}
.woocommerce.single-product ul.products li.product .price del { /* discounted price on sale items */
    color: #999 !important;
}
.single-product .related.products a.button {
    font-size: .7em; /* make buttons smaller */
}
@media only screen and (max-width: 767px) {
    .woocommerce.single-product ul.products li.product:nth-child(3n) {
        display: none; /* on small screens the third product drops below so it looks bad but making them be inline would be too tight, so this removes it */
   }
    .woocommerce.single-product ul.products li.product:nth-child(n) {
        margin: 0 2% 11% 2% !important;
        min-width: 46%;
        width: 100%!important;
   }
}
@media only screen and (max-width: 980px) {
    .woocommerce.single-product .products ul, .woocommerce.single-product ul.products {
        margin: 0 8% 1em;
   }
}
@media only screen and (max-width: 1280px) {
    .woocommerce.single-product ul.products li.product .woocommerce-loop-product__title {
        font-size: 24px !important;
   }
}
/******************************************/
/*************** SALE BADGES **************/
/******************************************/
.woocommerce.single-product div.product.sale .et_pb_title_container:before, .single-product span.onsale {
    display: block;
    text-align: center;
    background: #00adad !important;
    color: #fff;
    font-weight: 700 !important;
    border: 0;
}
.woocommerce.single-product div.product.sale .et_pb_title_container:before { /* badge above h1 post title */
    content: "SALE!"!important;
    position: absolute;
    top: -1.8em;
    right: 35%;
    font-family: inherit;
    font-size: 1em;
    padding: 0;
    width: 70px;
    height: 70px;
    line-height: 70px;
    border-radius: 50%;
    transform: rotate(6deg);
    -webkit-transform: rotate(6deg);
}
.single-product span.onsale { /* badge on default summary box */
    position: relative;
    margin-top: 8% !important;
    margin-bottom: -8% !important;
    top: 20px !important;
    left: -15% !important;
    width: 120px;
    height: 120px;
    font-size: 1.8em;
    line-height: 120px!important;
    padding: 0 !important;
    text-transform: uppercase;
    border-radius: 50% !important;
    transform: rotate(-8deg);
    -webkit-transform: rotate(-8deg);
}
.woocommerce.single-product ul.products li.product .onsale { /* badge on related products */
    position: absolute;
    top: -20px !important;
    font-size: 1em !important;
    width: 70px;
    height: 70px;
    line-height: 70px !important;
  }
@media only screen and (max-width: 768px) {
    .single-product span.onsale {
        left: -30% !important;
		width: 90px !important;
		height: 90px !important;
		line-height: 90px !important;
   }
    .woocommerce.single-product div.product.sale .et_pb_title_container:before {
        top: -1.7em;
        right: 25%;
        font-size: .7em;
        width: 50px;
        height: 50px;
        line-height: 50px !important;
   }
}
@media only screen and (max-width: 1024px) {
    .single-product span.onsale {
        font-size: 1.2em;
   }
    .woocommerce.single-product ul.products li.product .onsale {
        font-size: .8em !important;
        width: 60px !important;
        height: 60px !important;
        line-height: 60px!important;
   }
}
/*************************************************************************************************************/
/*** SEPARATE MEDIA QUERIES FOR TYPOGRAPHY ON LARGE SCREENS - OPTIONAL AND MAY BE MOOT BASED ON YOUR FONTS ***/
/*************************************************************************************************************/
@media only screen and (min-width: 1600px) {
	body .woocommerce.single-product p,
	.woocommerce.single-product p {
		font-size: 22px !important;
		line-height: 1.6em;
	}
	.woocommerce-single-product .et_pb_blurb p,
	.woocommerce.single-product .et_pb_testimonial_meta {
		font-size: 18px !important;
	}
	span.woocommerce-Price-amount.amount {
		font-size: 30px;
	}
	.woocommerce.single-product .et_pb_title_container h1 {
		font-size: 4em !important;
	}
	.woocommerce.single-product h2,
	.woocommerce.single-product .related h2 {
		font-size: 2.5em !important;
	}
	.woocommerce.single-product h3,
	.woocommerce.single-product ul.products li.product h2.woocommerce-loop-product__title {
		font-size: 1.8em !important;
	}
	.woocommerce.single-product span.onsale,
	.woocommerce.single-product ul.products li.product .onsale,
	.woocommerce.single-product div.product.sale .et_pb_title_container:before {
		font-size: 2em !important;
		width: 140px !important;
    	height: 140px !important;
    	line-height: 140px!important;
	}
	.woocommerce.single-product .et_pb_button.et_pb_promo_button {
		font-size: 1.2em !important;
	}
	.woocommerce.single-product .et_pb_blurb .et-pb-icon {
		font-size: 40px !important;
	}
}