.milestone_list {
    float:left;
    width: 15%;
    margin: 1em 0 0 15px;
}

.milestone {
    border: #d7d7d7 solid 1px;
    margin-bottom: 18px;
}

.milestone h4 {
    background: #f7f7f7;
    font-weight: bold;
    font-size: 12px;
    text-align: center;
    border-bottom: 1px solid #999;
    height: 17px;
    margin: 0;
    padding: 0;
}

.milestone td {
    font-size: 11px;
    color: #555;
}

.milestone_list {
    float:left;
    width: 15%;
    margin: 1em 0 0 15px;
}

.milestone {
    border: #d7d7d7 solid 1px;
    margin-bottom: 18px;
}

.milestone h4 {
    background: #f7f7f7;
    font-weight: bold;
    font-size: 12px;
    text-align: center;
    border-bottom: 1px solid #999;
    height: 17px;
    margin: 0;
    padding: 0;
}

.milestone table {
    padding: 0 4px;
}

.milestone td {
    font-size: 11px;
    color: #555;
}

Add a little padding around the milestone table.
Add a little padding around the milestone table.