The ‘happiest’ sounding of the modes, the Ionian is identical to the major scale, so it’s highly likely you’re already playing it on guitar ... (three-note diatonic chords) upon each ...
This riff also includes a section of diatonic 3rds that outline the chords of G major, F# augmented, D# diminished and C ...
Haydn’s Symphony No. 101 in D major, ‘The Clock’, is in a major key and uses mainly diatonic chords: A dominant seventh is used at the end of the phrase before the first time bar.