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>
    <linearGradient
        id="b"
        x1="19.5"
        x2="44.478"
        y1="32.011"
        y2="32.011"
        href="#a"
    />
    <path
        fill="url(#a)"
        d="M53 3.5H11A7.508 7.508 0 0 0 3.5 11v42a7.508 7.508 0 0 0 7.5 7.5h42a7.508 7.508 0 0 0 7.5-7.5V11A7.508 7.508 0 0 0 53 3.5zM57.5 53a4.505 4.505 0 0 1-4.5 4.5H11A4.505 4.505 0 0 1 6.5 53V11A4.505 4.505 0 0 1 11 6.5h42a4.505 4.505 0 0 1 4.5 4.5z"
    />
    <path
        fill="url(#b)"
        d="M43 30.5h-9.5V21a1.5 1.5 0 0 0-3 0v9.5H21a1.5 1.5 0 1 0 0 3h9.5V43a1.5 1.5 0 1 0 3 0v-9.5H43a1.5 1.5 0 0 0 0-3z"
    />
</svg>