/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    background-color: rgba(26, 26, 26, 0.9);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 0;
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 999;
    -webkit-tap-highlight-color: rgba(255, 255, 255, 0.1);
    touch-action: manipulation;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background-color: rgba(31, 31, 31, 0.95);
    border-color: rgba(255, 255, 255, 0.15);
    transform: translateY(-2px);
}

.back-to-top:active {
    transform: translateY(0);
}

.back-to-top svg {
    width: 20px;
    height: 20px;
    stroke: currentColor;
}

/* Loading skeleton for projects */
.project-card.loading {
    pointer-events: none;
}

.project-card.loading .project-image {
    background: linear-gradient(90deg, #161616 25%, #1a1a1a 50%, #161616 75%);
    background-size: 200% 100%;
    animation: loading-shimmer 1.5s infinite;
}

@keyframes loading-shimmer {
    0% {
        background-position: 200% 0;
    }
    100% {
        background-position: -200% 0;
    }
}