*{
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    display: flex;
    height: 100vh;
    overflow: hidden;
    justify-content: center;
    align-items: center;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.container{
    display: flex;
    flex-direction: column;
}
.progress-bar{
    display: flex;
    list-style: none;
    margin-bottom: 1rem;
    position: relative;
}

.progress-bar #bar{
    position: absolute;
    top: 50%;
    height: .3rem;
    width: 0%;
    background-color: blue;
    transition: all 0.4s ease-in;
}

.progress-bar::before{
    content: '';
    background-color: lightblue;
    height: .3rem;
    width: 100%;
    position: absolute;
    top: 50%;
    z-index: -2;
    opacity: .2;
}

.btn-wrapper{
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn{
   padding: 1rem;
   border-radius: 10px;
   cursor: pointer;
   margin: .5rem;
   background-color: blue;
   color: #fff;
}

.btn:disabled{
    background-color: lightblue;
    cursor: not-allowed;
}

.progress-bar .item{
    border: 4px solid lightblue;
    border-radius: 50%;
    margin-right: 2rem;
    position: relative;
    transition: all .7s ease-in-out .2s;
    background: #fff;
}

.progress-bar .item:last-child{
    margin-right: 0;
}

.progress-bar li{
    background: #fff;
    margin: 1rem;
}

.progress-bar .active{
   border-color: darkblue;
}