body {
    font-family: Arial, sans-serif;
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
    text-align: center;
}

.button-group {
    margin-bottom: 30px;
}

button {
    padding: 10px 20px;
    margin: 0 10px;
    font-size: 18px;
    cursor: pointer;
    border: 2px solid #3498db;
    background-color: white;
    color: #3498db;
    border-radius: 5px;
    transition: all 0.3s;
}

button.selected {
    background-color: #3498db;
    color: white;
}

button:hover {
    background-color: #3498db;
    color: white;
}

.stats {
    display: flex;
    justify-content: space-around;
    margin-top: 30px;
}

.stat-box {
    padding: 20px;
    border: 1px solid #ddd;
    border-radius: 5px;
    background-color: #f9f9f9;
    width: 45%;
}

.stat-label {
    font-weight: bold;
    color: #555;
    margin-bottom: 10px;
}

.stat-value {
    font-size: 24px;
    color: #333;
}

.timeline {
    margin-top: 20px;
    border-left: 3px solid #3498db;
    padding-left: 20px;
    max-width: 100%;
}

.checkpoint {
    margin-bottom: 30px;
    padding: 15px;
    background-color: #f9f9f9;
    border-radius: 8px;
    border: 1px solid #ddd;
    position: relative;
}

.checkpoint::before {
    content: "";
    position: absolute;
    left: -21px;
    top: 20px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: #3498db;
}

.checkpoint-name {
    font-weight: bold;
    color: #3498db;
    margin-bottom: 10px;
    font-size: 18px;
}

.checkpoint-date {
    font-size: 14px;
    color: #666;
    margin-bottom: 15px;
}

.checkpoint-stats {
    display: flex;
    justify-content: space-between;
    gap: 10px;
}

.checkpoint-stat {
    flex: 1;
    text-align: center;
    padding: 8px;
    background-color: #fff;
    border-radius: 4px;
    border: 1px solid #eee;
}

.checkpoint-stat-label {
    font-size: 12px;
    color: #888;
    margin-bottom: 5px;
}

.checkpoint-stat-value {
    font-size: 16px;
    font-weight: bold;
    color: #333;
}

.checkpoint.current {
    background-color: #e8f4fc;
    border-color: #3498db;
}

.checkpoint.current::before {
    background-color: #2980b9;
}

.checkpoint.future {
    opacity: 0.7;
    background-color: #f5f5f5;
}

.checkpoint.future::before {
    background-color: #bdc3c7;
}

.checkpoint.past {
    background-color: #f0f8f0;
    border-color: #2ecc71;
}

.checkpoint.past::before {
    background-color: #27ae60;
}