page title with h2 tags..

Hello, I saw that the title page is written in <h2> and not <h1>. If I want to change the font, size, color of the title pages, I have to change this value in style.css

h2 {
	font-size: 26px;
        text-align: center;
        font-family: 'Monotype Corsiva';
        color:#FF4D00;
}

Why the title depends on the h2? my problem? When I create a new page I think the title is with h1 tag because, for example, if I do not insert the h2 tags, wordpress seo plugin Yoast tells me that h2 is missing (rightly). So the problem is only in viewing the site? My site is www. Salento casa vacanza . net The title page is "affitto casa vacanze nel Salento" Thanks