The header is too prominent currently. We've found that the following works quite well:

• reduce the height of the header (e.g. top padding to 5px).
• set a background color of our very light gray (color 24: #f2f2f2). The list of rows then slides nicely underneath the header.
• set bottom border to only 1px (remove "medium")
• set font-weight to "normal"
• try to set font color to "#666". If too light, try "#333".