.logo {
    display: inline-flex;
    align-items: center;
    height: 1em; /* or inherit from font-size if ye prefer */
}

.logo svg {
    width: 100%;
    height: 100%;
    display: block;
    overflow: visible; /* let the glow spill out */
}

.logo svg * {
    animation: glow 10s infinite linear;
}