/* =================================
   SCROLL TO TOP BUTTON
   ================================= */

.scroll-top-btn {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 3.5rem;
    height: 3.5rem;
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    z-index: 999;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.scroll-top-btn::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 50%;
    padding: 2px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-mid));
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask-composite: exclude;
    opacity: 0.5;
    transition: opacity 0.3s ease;
}

.scroll-top-btn i {
    font-size: 1.25rem;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-mid));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    transition: all 0.3s ease;
}

/* Active State (Visible) */
.scroll-top-btn.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

/* Hover State */
.scroll-top-btn:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0, 102, 255, 0.25);
    background: rgba(255, 255, 255, 0.1);
}

.scroll-top-btn:hover::before {
    opacity: 1;
}

/* Click/Active State */
.scroll-top-btn:active {
    transform: scale(0.95);
}

/* Responsive */
@media (max-width: 768px) {
    .scroll-top-btn {
        bottom: 1.5rem;
        right: 1.5rem;
        width: 3rem;
        height: 3rem;
    }
}