First of all, style is a literary term which describes the manner in which the story is being told. In the case of "Casey at the Bat," the poem (or ballad) is a narrative being told by an unnamed speaker, but obviously one who has great admiration for the slugging main character. The theme is baseball, of course, and there are multiple references to the sport, including many 19th century terms and allusions. The character of Casey is probably based on the old baseball hero, Mike "King" Kelly, for which a famous song, "Slide, Kelly, Slide" was written. The poem is written in rhyming verse separated into four-line stanzas with an AABB rhyme scheme. Beginning in a realistic, somber tone, since the local Mudville nine is losing and the outcome appears hopeless, it moves on to a hopeful and almost mythic narrative once the local superstar Casey struts to the plate. There is great humor within the lines, and the poem concludes with a highly ironic and totally unexpected twist at the end.
style is all abt de grammer present in the novel like idioms, tense, letter, simili, metafor. pharses etc.