*{
    box-sizing: border-box;
    padding: 0;
    margin: 0;
    font-family: sans-serif;
}

body{
    background-color: #2c3e50;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    color: #ecf0f1;
}

.container{
    text-align: center;
}

.timeline-box{
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
    margin: 30px;
    max-width: 100%;
    width: 350px;
}

.timeline{
    background: #f39c12;
    position: absolute;
    top: 50%;
    left: 0;
    transform: translateY(-50%);
    height: 4px;
    width: 0%;
    z-index: -1;
    transition: width 0.1s ease-in-out;
}

.timeline-box::before{
    content: "";
    background: #34495e;
    position: absolute;
    top: 50%;
    left: 0;
    transform: translateY(-50%);
    height: 9px;
    width: 100%;
    z-index: -1;
}

.circle{
    background: #f39c12;
    border-radius: 50%;
    color: #2c3e50;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    height: 60px;
    width: 60px;
    transition: 0.4s ease;
}

.circle.active{
    /* border-color: #f39c12; */
    color: #2c3e50;
    border: 5px solid whitesmoke;
}

.btn{
    background-color: #e74c3c;
    border: 0;
    border-radius: 6px;
    color: #ecf0f1;
    cursor: pointer;
    font-family: inherit;
    font-size: 18px;
    padding: 12px 30px;
    margin-left: 10px;
    transition: transform 0.2s ease-in-out;
}

.btn:active{
    transform: scale(0.98);
}

.btn:disabled{
    background-color: #7f8c8d;
    cursor: not-allowed;
}

.btn:focus{
    outline: none;
}