.d-flex {
    display: flex;
}

.justify-center {
    justify-content: center;
}

.align-center {
    align-items: center;
}

.ma-auto { margin: auto; }
.ma-1 { margin: 4px; }
.ma-2 { margin: 8px; }
.ma-3 { margin: 12px; }
.ma-4 { margin: 16px; }

.mt-auto { margin-top: auto; }
.mt-1 { margin-top: 4px; }
.mt-2 { margin-top: 8px; }
.mt-3 { margin-top: 12px; }
.mt-4 { margin-top: 16px; }

.mb-auto { margin-bottom: auto; }
.mb-1 { margin-bottom: 4px; }
.mb-2 { margin-bottom: 8px; }
.mb-3 { margin-bottom: 12px; }
.mb-4 { margin-bottom: 16px; }

.ml-auto { margin-left: auto; }
.ml-1 { margin-left: 4px; }
.ml-2 { margin-left: 8px; }
.ml-3 { margin-left: 12px; }
.ml-4 { margin-left: 16px; }

.mr-auto { margin-right: auto; }
.mr-1 { margin-right: 4px; }
.mr-2 { margin-right: 8px; }
.mr-3 { margin-right: 12px; }
.mr-4 { margin-right: 16px; }