body{ background:url(http://ferdinand.jp/wp-content/uploads/2020/09/ea376a2cfc3f5b4288078e5663f33860_s-1.jpg); } .p-info { /* background: #ffffff; */ /* color: #000000; */ } .p-triangle::before { z-index: -1; position: absolute; top: -1px; left: 0; border-width: 75px; border-style: solid; border-color: #0000; content: ""; -webkit-filter: drop-shadow(2px 2px 4px rgba(0, 0, 0, 0.5)); filter: drop-shadow(2px 2px 4px rgba(0, 0, 0, 0.5)); }