:root{ 
    --white:#fff; 
    --color: #D31122;
    --main-color:#A1051D;
}

.btn{
    color: var(--white);
    background: var(--color); 
    font-family:'Roboto Condensed', sans-serif;
    font-size: 18px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    padding: 8px 15px;
    border-radius: 0;
    border: none;
    position: relative;
    box-shadow: -4px -4px 0px var(--white);
    z-index: 1;
    transition: all 0.35s;
} 

.btn:hover,
.btn:focus{ 
    color: var(--white); 
    box-shadow: 4px 4px 0px var(--white), 10px 10px 0px var(--main-color);
}

.btn:before{
    content: "";
    background: var(--main-color);
    width: 100%;
    height: 100%;
    position: absolute;
    left: 0;
    top: 0;
    transition: 0.3s all;
    z-index: -1;
}

.btn:hover:before{ width: 50%; }

@media only screen and (max-width: 767px){
    .btn{ margin-bottom: 30px; }
}