#btn-back-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 1030;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
}
#btn-back-to-top.show {
    opacity: 1;
    visibility: visible;
}
.rounded-circle {
    width: 30px;
    height: 30px;
    text-align: center;
    padding: 0;
    font-size: 12px;
    line-height: 1.428571429;
    border-radius: 15px;
}
.rounded-circle.btn-lg {
    width: 50px;
    height: 50px;
    padding: 0;
    font-size: 18px;
    line-height: 1.33;
    border-radius: 25px;
}

/* Logo color inversion for dark theme */
[data-bs-theme="dark"] .navbar-brand img {
    filter: invert(1);
}