This REPLACE statement adds to the child style definition the style element color_list, which also exists in the parent style definition. You can think of the REPLACE statement as replacing the definition of color_list in the parent style defintion. The REPLACE statement doesn't actually change the parent style definition, but PROC TEMPLATE builds the child style definition as if it had changed the parent. All style elements that use the user-defined attributes that color_list defines (fgB2, fgB1, and so forth) use the attributes that are specified in the REPLACE statement, not the ones that are specified in styles.default. Therefore, if you change a color here, you change every occurrence of the color in the HTML output. This REPLACE statement changes the values of fgA2 andfgA from a greenish blue to a pure blue and from a slightly darker greenish blue to a purple. (The first two digits of the hex value represent red, the next two represent green, and the last two represent blue.)
   replace color_list /
      'fgB2' = cx0066AA
      'fgB1' = cx004488
      'fgA4' = cxAAFFAA
      'bgA4' = cx880000
      'bgA3' = cxD3D3D3
 /* changed from cx0033AA */
      'fgA2' = cx0000FF
      'bgA2' = cxB0B0B0
      'fgA1' = cx000000
      'bgA1' = cxF0F0F0
/* changed from cx002288 */
      'fgA' = cx660099
      'bgA' = cxE0E0E0;