.container{
    margin:0 auto;
    max-width: 400px;
    text-align: center;
    padding: 20px;
    font-family: "Roboto",sans-serif;
}
.title{
    font-size: 36px;
    margin-bottom:10px;
    color: #2c3e50;
}
.timer{
    font-size: 72px;
    color: #2c3e50;
}
button{
    font-size: 18px;
    padding: 10px 20px;
    margin:10px;
    color: white;
    border:none;
    border-radius: 4px;
    cursor: pointer;
    text-transform: uppercase;
    transition: opacity .3s
    ease-in-out ;
}
button:hover{
    opacity: 0.7;
}
#start{
    background-color: #27ae60;
}
#stop{
    background-color: #c0392b;
}
#reset{
    background-color: #7f8c8d;
}