.period-info {
    margin: 20px;
    padding: 20px;
    background-color: #f8f9fa;
    border-radius: 8px;
    border: 1px solid #ddd;
    font-family: Arial, sans-serif;
}
.period-box {
    display: inline-block;
    margin: 10px;
    padding: 15px;
    border-radius: 6px;
    min-width: 200px;
    text-align: center;
}
.period1 { background-color: #e8f5e8; border-left: 4px solid green; }
.period2 { background-color: #f0e8f5; border-left: 4px solid purple; }
.period3 { background-color: #ffe8e8; border-left: 4px solid red; }
.overall { background-color: #e8f0ff; border-left: 4px solid blue; }
.method-note { margin-top: 20px; font-size: 14px; color: #666; }