.btn-vk {
    background-color: #1877f2;
    border-color: #1877f2;
    color: #fff;
    transition: background-color 0.3s ease, border-color 0.3s ease, transform 0.3s ease;
}

.btn-vk:hover {
    background-color: #0d5bbf;
    border-color: #0d5bbf;
    transform: translateY(-2px);
    color: #fff;
}