<div class="mask-parent">
  <div class="mask"></div>
</div>

@import url("https://fonts.googleapis.com/css2?family=Exo:wght@600&display=swap");

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  width: 100vw;
  min-height: 100vh;
  font-family: "Exo", Arial, sans-serif;
  background-color: #557;
  color: #fff;
  display: grid;
  padding: 30px;
  gap: 30px;
  place-content: center;
}

:root {
  --x-offset: 10px;
  --y-offset: 10px;
  --blur-radius: 10px;
  --color: #f36;
  --shadow: var(--x-offset) var(--y-offset) var(--blur-radius) var(--color);
}

.mask-parent {
  filter: drop-shadow(var(--shadow));
}

.mask {
  width: 50vh;
  aspect-ratio: 4 / 3;
  background: #09f;
  mask-image: radial-gradient(circle, #000 50%, transparent 50%);
  mask-size: cover;
  mask-position: center;
}