How to edit mobile layout?

Theme responsive layout is handled by media queries. The appropriate width values of iDevices are listed below:

• @media only screen and (max-width: 990px) – iPad portrait
• @media only screen and (min-width: 739px) and (max-width: 990px) – also iPad portrait (with lower bound)
• @media only screen and (min-width: 479px) and (max-width: 739px) – iPhone landscape
• @media only screen and (max-width: 479px) – iPhone portrait
• @media only screen and (min-width: 998px) – also iPad portrait (for specific web-sites width)

You can try to add new media queries in Theme Options -> Advanced -> Custom CSS