To change layout of prodct page in woocommerce, and if specially you want to change the width of product summary and featured image, then use below code:

 

h1, h2, h3, h4, h5, h6 {
color: #e53b3b;
}

@media (min-width: 768px) {
.storefront-full-width-content.single-product div.product .images {
width: 60%;
}
}

@media (min-width: 768px) {
.storefront-full-width-content.single-product div.product .summary {
width: 30%;
}
}