.btn-primary {
    color: #fff;
    background-color: #052439;
    border-color: #052439;
}

.btn-primary:hover {
    color: #fff;
    background-color: #041d2f; /* un poco más oscuro */
    border-color: #031724;     /* más oscuro aún */
}

.btn-check:focus + .btn-primary, .btn-primary:focus {
    color: #fff;
    background-color: #041d2f;
    border-color: #031724;
    box-shadow: 0 0 0 .25rem rgba(5, 36, 57, 0.5); /* sombra basada en el color base */
}

.btn-check:active + .btn-primary,
.btn-check:checked + .btn-primary,
.btn-primary.active,
.btn-primary:active,
.show > .btn-primary.dropdown-toggle {
    color: #fff;
    background-color: #031724;
    border-color: #02131d;
}

.btn-check:active + .btn-primary:focus,
.btn-check:checked + .btn-primary:focus,
.btn-primary.active:focus,
.btn-primary:active:focus,
.show > .btn-primary.dropdown-toggle:focus {
    box-shadow: 0 0 0 .25rem rgba(5, 36, 57, 0.5);
}

.btn-primary.disabled, .btn-primary:disabled {
    color: #fff;
    background-color: #052439;
    border-color: #052439;
}