button {
 border: none;
 padding: 0.7em 2em;
 font-size: 18px;
 font-family: inherit;
 background-blend-mode: multiply;
 color: rgb(235, 234, 234);
 border-radius: 9px;
 background: linear-gradient(225deg, #181818, #2e2e2e);
 box-shadow: -5px 5px 10px #191919,
             5px -5px 10px #292929;
}

button:hover {
 background: #212121;
 transition: background 1s ease;
 box-shadow: -5px 5px 10px #191919,
             5px -5px 10px #292929;
}

button:active {
 transition: box-shadow .1s ease;
 border-radius: 9px;
 background: #212121;
 box-shadow: inset -5px 5px 10px #191919,
              inset 5px -5px 10px #292929;
}

span {
 opacity: 0.5;
 transition: opacity 0.2s ease;
}

button:hover span {
 opacity: 0.7;
}