/* --- Back To Top Premium Button --- */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    z-index: 9999;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px) scale(0.8);
    transition: all 0.5s cubic-bezier(0.23, 1, 0.32, 1);
}

[data-theme="dark"] .back-to-top {
    background: rgba(255, 255, 255, 0.05);
    border-color: rgba(255, 255, 255, 0.1);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

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

.back-to-top:hover {
    transform: translateY(-5px) scale(1.05);
    box-shadow: 0 15px 40px rgba(109, 40, 217, 0.2);
    border-color: var(--primary-violet);
}

[data-theme="dark"] .back-to-top:hover {
    box-shadow: 0 0 25px rgba(109, 40, 217, 0.4);
}

/* Scroll Progress Ring */
.btt-progress-svg {
    position: absolute;
    top: -1px;
    left: -1px;
    width: calc(100% + 2px);
    height: calc(100% + 2px);
    transform: rotate(-90deg);
}

.btt-progress-circle {
    fill: none;
    stroke: var(--primary-violet);
    stroke-width: 2.5;
    stroke-linecap: round;
    stroke-dasharray: 157; /* 2 * PI * R (R=25) */
    stroke-dashoffset: 157;
    transition: stroke-dashoffset 0.1s linear;
}

/* Icon */
.back-to-top i {
    font-size: 1.5rem;
    color: var(--text-primary-light);
    transition: color 0.3s ease;
    z-index: 2;
}

[data-theme="dark"] .back-to-top i {
    color: var(--text-primary-dark);
}

.back-to-top:hover i {
    color: var(--primary-violet);
}

/* Responsive */
@media (max-width: 768px) {
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 44px;
        height: 44px;
    }
    
    .back-to-top i {
        font-size: 1.25rem;
    }
}