@keyframes spinner-border {
    to { transform: rotate(360deg); }
} 
.spinner-border {
    display: inline-block;
    width: 1.3rem;
    height: 1.3rem;
    vertical-align: text-bottom;
    border: .25em solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
    -webkit-animation: spinner-border .75s linear infinite;
    animation: spinner-border .75s linear infinite;
}
.spinner-border-2x {
    display: inline-block;
    width: 2.6rem;
    height: 2.6rem;
    vertical-align: text-bottom;
    border: .25em solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
    -webkit-animation: spinner-border .75s linear infinite;
    animation: spinner-border .75s linear infinite;
}
.spinner-border-3x {
    display: inline-block;
    width: 3.9rem;
    height: 3.9rem;
    vertical-align: text-bottom;
    border: .25em solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
    -webkit-animation: spinner-border .75s linear infinite;
    animation: spinner-border .75s linear infinite;
}
.spinner-border-4x {
    display: inline-block;
    width: 5.2rem;
    height: 5.2rem;
    vertical-align: text-bottom;
    border: .25em solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
    -webkit-animation: spinner-border .75s linear infinite;
    animation: spinner-border .75s linear infinite;
}
.spinner-border-sm {
    display: inline-block;
    width: 0.8rem;
    height: 0.8rem;
    vertical-align: text-bottom;
    border: .25em solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
    -webkit-animation: spinner-border .75s linear infinite;
    animation: spinner-border .75s linear infinite;
}