인라인(inline) 요소
태그 : span, a, small, big, em, u, s, del, br, q, b, strong,
mark, sub, sup, video, audio
블록(block) 요소
태그 : div, table, figure, figcaption, caption, header,
nav, footer, section, article, aside, p, blockquoute, ul,
ol, li, td, th, form, hr, h1~h6
인라인블록(inline-block) 요소
태그 : img, button, fontawesome