Blur color at the edges above and below in Chrome Mobile

When you open the site in the Chrome browser on your Android phone, there is a blur of color along the edges (top / bottom), as shown in the picture. In this example, the upper horizontal bar is implemented via box-shadow , the lower vertical border . The problem is that at the junction with another block, when viewed from the phone, a half-pixel light bar will be visible, which spoils the design. There is no such render on the PC. How can I solve the problem? Or where to read?

Actually, there is no blur in the code:

 box-shadow: inset 0 -2px 0 0px #1d5399; 

and

 border-left: 2px solid #1d5399;