The sun's spectrum is very complex, and indeed there are a lot of "lines" both light and dark (emission and absorption) amidst a sea of what looks to be continuous frequencies. Note that the atoms you study in a textbook are idealizations. read more
The photosphere emits all the electromagnetic radiation of a continuous spectrum, when it pass through the solar atmosphere, certain radiations are absorbed by the molecules, so the absorption spectrum gives the details of the solar atmosphere. read more
I got a doubt here, i,e even the sunlight has the radiations emitted by the atoms of the elements which compose the sun, still spectra is continuous, which is in opposition to the statement that atomic spectra is discontinuous. read more