Design.css

/* コンテンツ幅の拡張 */
#content, .breadcrumb {
	width: 55%; /* 80%〜95%の範囲を推奨 */
}

#content, #blog-title, .breadcrumb  {
	min-width: 800px;
}

.header-image-enable #blog-title-inner {
	background: no-repeat center;
	background-size: cover;
}

#main {
	margin-right: 300px;
}

.entry-content img, .entry-content iframe, .entry-content embed { 
	max-width: 100%;
}

#box2 {
	margin-left: -300px;
	float: right;
}

.page-entry .pager-next a,.page-entry .pager-prev a, .page-archive .pager-next a, .page-archive .pager-prev a {
	width: 48%;
}

.page-index .pager-next a , .page-search .pager-next a, .pager, #wrapper  {
	width: 100%;
}