Keep your layouts flexible: * Avoid specifying widths and especially heights of individual elements unless really necessary. Allow the content to determine dimensions. * Set percentage based widths on overall containers (columns / grids). Allow these to constrain the dimensions of elements within. (Simplify your page structure as much as possible and don't overuse these.) * Use max-width to prevent elements from exceeding the dimensions of their containers: img {max-width: 100%;}