style.css

:root{
    --line-border--fill: #3498db ;
    --line-border--empty: #e0e0e0;
}
*{
    box-sizing: border-box;
}
body{
background-color: #f6f7fb;
align-items: center;
margin: 0;
display: flex;
justify-content: center;
overflow: hidden;
height: 100vh;


}
.container{
    /* border: 1px solid red; */
    text-align: center;
}
.progress-container{
    /* border: 1px solid blue; */
    display:flex;
    justify-content: space-between;
    position:relative;
    margin-bottom: 30px;
    width: 350px;
    max-width: 100%;
}
.progress-container::before{
    content: '';
    /* border: 1px solid red; */
    background-color: var(--line-border--empty);
    position: absolute;
    top: 50%;
    left: 0;
    /* transform: translateY(-50%); */
    height: 4px;
    width: 100%;
    z-index: -1;
    transition: .4s ease;

}
.progress{
    /* border: 1px solid red; */
    background-color:var(--line-border--fill);
    position: absolute;
    top: 50%;
    left: 0;
    /* transform: translateY(-50%); */
    height: 4px;
    width: 0%;
    z-index: -1;
    transition: .4s ease;

}
#progress{
    /* border: 1px solid blue; */

}
.circle{
    background-color: #fff;
    color:#999;
    border-radius:50%;
    height:30px;
    width: 30px;
    display: flex;
    align-items: center;
    justify-content: center ;
    border: 3px solid var(--line-border--empty);
    transition: .4s  ease;
}
.circle.active{
    border-color: #3498db;
}

.btn{
    background-color: var(--line-border--fill);
    color: white;
    border-radius: 6px;
    cursor: pointer;
    padding: 8px 30px;
    margin: 5px;
    font-size: 14px;

}
.btn.active{
    transform: scale(.1);
}
.btn.focus{
    outline: 0;
}
.btn:disabled{
    background-color: var(--line-border--empty);
    cursor: not-allowed;
}