.timeline {
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
    background-color: var(--secondary-color);
    color: white;
}

.timeline::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    height: 6px;
    background-color: white;
    z-index: 1;
}

.timeline-item {
    position: relative;
    text-align: center;
    z-index: 2;
}

.timeline-item .circle {
    width: 70px;
    height: 70px;
    border-radius: 50%;
    background-color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 10px;
    transition: background-color 0.3s, color 0.3s;
}

.timeline-item i {
    font-size: 30px;
    color: var(--secondary-color);
    transition: color 0.3s;
}

.timeline-item.active .circle {
    background-color: var(--secondary-color);
    -webkit-box-shadow: inset 0px 0px 0px 5px rgb(255, 255, 255);
    -moz-box-shadow: inset 0px 0px 0px 5px rgb(255, 255, 255);
    box-shadow: inset 0px 0px 0px 5px rgb(255, 255, 255);
}

.timeline-item.active i {
    color: white;
}

.timeline-item span {
    display: block;
    font-size: 18px;
}

.year {
    font-size: 16px;
    margin-bottom: 10px;
}

.timeline-item:hover .circle {
    background-color: var(--secondary-color);
    cursor: pointer;
    -webkit-box-shadow: inset 0px 0px 0px 5px rgb(255, 255, 255);
    -moz-box-shadow: inset 0px 0px 0px 5px rgb(255, 255, 255);
    box-shadow: inset 0px 0px 0px 5px rgb(255, 255, 255);
}

.timeline-item:hover i {
    color: white;
}

.content-tab {
    display: none;
    padding: 20px;
    color: #333;
    margin-top: 20px;
    border-radius: 10px;
}

.content-tab.active {
    display: block;
}