.preloader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--bg-primary);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    transition: opacity 0.5s ease-in-out;
}

.preloader.fade-out {
    opacity: 0;
    pointer-events: none;
}

.loader {
    width: 50px;
    height: 50px;
    border: 3px solid var(--text-secondary);
    border-radius: 50%;
    border-top-color: var(--accent-color);
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.back-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--accent-color);
    color: var(--bg-primary);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 99;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background-color: var(--accent-color-hover);
    transform: translateY(-3px);
}