<div style="position:relative; background-color:#fff; margin:20px 5px 15px 5px; padding:20px 10px 10px 10px; border:solid 1px #ddd; box-shadow:1px 2px 5px rgba(0,0,0,.3);">右上にマステが貼られた紙に書く文章<div style="position:absolute; top:-10px; right:-5px; display:block; transform:rotate(5deg); -webkit-transform:rotate(5deg); border-left:dotted 2px rgba(0,0,0,.2); border-right:dotted 2px rgba(0,0,0,.2); box-shadow:0 0 3px rgba(0,0,0,.3); background-image: repeating-linear-gradient(-45deg, rgba(255,221,102,.3), rgba(255,221,102,.3) 8px, rgba(255,255,255,.3) 8px, rgba(255,255,255,.3) 16px); padding:3px 20px; font-size:1.2em;">マステに書く文字</div></div>