A user needs to add borders to color swatches on product pages because white swatches are invisible against the white site background, and partially white swatches look unappealing.
Two solutions were provided:
Solution 1 (Made4uo-Ribe):
Navigate to Shopify admin → Online Store → Themes → Actions → Edit code
Open the Assets folder and locate base.css, style.css, or theme.css
On our product pages, we have colour swatches like shown below, sometimes using html colour codes and sometimes using files (for the multi-coloured products). The white color swatch is invisible because the main background colour of our site is white, and we also don’t like the look of the colour swatches that are half white. How can I add a thin black line to all swatches, not just the selected colour (grey in the example below)?
Here a thing, when you selected a color there is a border color black. What I did I colored it red. and the none selected color black border. You can change the color you like.
From your Shopify admin dashboard, click on “Online Store” and then “Themes”.
Find the theme that you want to edit and click on “Actions” and then “Edit code”.
In the “Assets” folder, click on “base.css, style.css or theme.css” file, depending on which file your theme uses to store its CSS styles. At the bottom of the file, add the following CSS code: