.btn {
    text-align: center;
    padding: 5px;
    display: inline-block;
    -webkit-border-radius: 3px;
    -webkit-background-clip: padding-box;
}

.btn-primary {
    @extend .gradient-primary;
    &.hl { /* TODO */ }
}
.btn-secondary {
    @extend .gradient-secondary;
    &.hl { @extend .gradient-secondary-hl; }
}
.btn-secondary-alt {
    @extend .gradient-secondary-alt;
    &.hl { @extend .gradient-secondary-alt-hl; }
}