html, body {
    font-family: Verdana, sans-serif;
}
.main_container {
    display: flex;
    justify-content: flex-start;
    flex-wrap: wrap;
    padding: 10px;
}
.row_container {
    flex-wrap: wrap;
    display: flex;
    justify-content: flex-start;
    padding: 10px;
}
.row_item {
    padding: 10px;
}
.chart {
    padding: 10px;
}
.form-field {
    padding-top: 10px;
}
input {
    width: 100px;
    /* text-align: right; */
}
.chart {
    height: 400px; 
    width: 650px;
}
input:invalid {
    border: 2px dashed red;
}
input:valid {
    border: 1px solid black;
}