blue square background, for banner, poster, event, celebrations and various works

abstract background backdrop banner template bright colored copy empty focus gradation luminous marketing mix modern pattern smooth surface vibrant watercolor blend blue poster blur blurred blurry colorful composition digital effect graphic layout media post sale simple social space square squared texture textured trendy vivid wall material banner poster background template layout marketing sale ad advertisement web online plain promo event party celebration media social anniversary fashion empty story promotion professional post company corporate insert abstract text words color blend colorful raster card greeting entertainment textures texture textured gradient pattern festive holiday happy announcements birthday backgrounds square