<svg viewBox="0 0 330 340" width="200">
  <defs>
    <filter id="shadow">
      <feDropShadow dx="3" dy="2" stdDeviation="4" flood-color="#000" flood-opacity="1" />
    </filter>
  </defs>
  <path d="M150,10 290,290 10,290z" fill="red" transform="translate(0,0)" />
  <g transform="translate(30,30)">
    <path d="M150,10 290,290 10,290z" fill="#000" filter="url(#shadow)" />
    <path d="M150,10 290,290 10,290z" fill="#333" />
  </g>
</svg>

body {
  background: #333;
}