Add

<svg
    xmlns="http://www.w3.org/2000/svg"
    width="512"
    height="512"
    viewBox="0 0 64 64"
>
    <linearGradient
        id="a"
        x1="3.5"
        x2="60.5"
        y1="32"
        y2="32"
        gradientUnits="userSpaceOnUse"
    >
        <stop offset="0" stop-color="#ff3cac" />
        <stop offset=".5" stop-color="#784ba0" />
        <stop offset="1" stop-color="#2b86c5" />
    </linearGradient>
    <path
        fill="url(#a)"
        d="M53 3.5H11A7.503 7.503 0 0 0 3.5 11v42a7.503 7.503 0 0 0 7.5 7.5h42a7.503 7.503 0 0 0 7.5-7.5V11A7.503 7.503 0 0 0 53 3.5zm-10 30h-9.5V43a1.5 1.5 0 0 1-3 0v-9.5H21a1.5 1.5 0 0 1 0-3h9.5V21a1.5 1.5 0 0 1 3 0v9.5H43a1.5 1.5 0 0 1 0 3z"
    />
</svg>