Gracias por el curso

*::before,
*::after {
 box-sizing: border-box;
}

:root {
 --border-radius-x: 180px;
 --border-radius-y: 100px;
}
.play {
 width: 180px;
 height: 180px;
 margin-left: 180px;
 margin-top: 75px;
 background: transparent;
 border-width: 90px 0 90px 180px;
 border-style: solid;
 border-color: transparent  transparent  transparent white;
}

.box {
 width: 500px;
 height: 350px;
 background: hsl(10, 90%, 50%);
 margin: 100px auto;
 padding-top: 0.1px;
 border-top-left-radius: var(--border-radius-x) var(--border-radius-y);
 border-top-right-radius: var(--border-radius-x) var(--border-radius-y);
 border-bottom-right-radius: var(--border-radius-x) var(--border-radius-y);
 border-bottom-left-radius: var(--border-radius-x) var(--border-radius-y);
}~~~