/* SCROLL TO TOP */
.scroll-to-top-btn {
    position: fixed; bottom: 30px; left: 50%; right: auto; transform: translateX(-50%) translateY(100px);
    background: var(--accent); color: var(--black); border: var(--border); border-radius: 50%;
    width: 60px; height: 60px; display: flex; align-items: center; justify-content: center;
    font-family: var(--font-bold); font-size: 0.9rem; cursor: pointer; z-index: 900;
    box-shadow: 6px 6px 0 var(--black); 
    transition: opacity 0.4s ease, transform 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275), background 0.3s, box-shadow 0.3s;
    opacity: 0; pointer-events: none; text-decoration: none;
}
.scroll-to-top-btn.show { opacity: 1; pointer-events: auto; transform: translateX(-50%) translateY(0); }
.scroll-to-top-btn:hover { 
    transform: translateX(-50%) translateY(-5px) scale(1.1); 
    box-shadow: 8px 8px 0 var(--primary); background: var(--bg); color: var(--primary); 
}