.btn-flat {
    background-color: rgba(0,0,0,0.2);
}

.btn-flat:hover {
    background-color: rgba(0,0,0,0.1);
}


/* do not group these rules */
*::-webkit-input-placeholder {
    color: grey;
}
*:-moz-placeholder {
    /* FF 4-18 */
    color: grey;
}
*::-moz-placeholder {
    /* FF 19+ */
    color: grey;
}
*:-ms-input-placeholder {
    /* IE 10+ */
    color: grey;
}