This page contains a neutral colors chart and a general-purpose color chart. You can use the colors in the palettes with either HTML or CSS. Click on the color code to select it, then you can copy and paste it. Click on the Toggle button to convert from Hex to RGB and back. The charts are printed in tabular fashion so you can narrow your browser window with the palette and compare the colors to your design side-by-side.
Do not use the color names in your code, because they are non-standard. Use either the HEX or RGB values.