#solve-button {
font-family: "Sen", sans-serif;
position: absolute;
top: 15px;
right: 15px;
display: inline-block;
background-color: #f5f5f5;
font-size: 15px;
padding: 5px 10px;
margin: 2.5px 0;
border: 2px solid black;
border-radius: 5px;
cursor: pointer;
-webkit-transition-property: color, background-color;
transition-property: color, background-color;
-webkit-transition-duration: 250ms;
transition-duration: 250ms;
}

#solve-button:hover {
background-color: #0c75e8;
color: white;
}