/* AI Style Back to Top Button */
.ai-back-to-top {
    position: fixed;
    right: 30px;
    bottom: 30px;
    width: 50px;
    height: 50px;
    cursor: pointer;
    z-index: 99;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

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

/* SVG Base Styles */
.ai-back-to-top svg {
    width: 100%;
    height: 100%;
}

.ai-outer {
    filter: drop-shadow(0 0 2px #31DFDF);
}

.ai-circle {
    stroke: #1599fc;
    stroke-width: 3.5;
    transition: all 0.3s ease;
    fill: none;
}

.ai-progress {
    stroke: #43e794;
    stroke-width: 3.5;
    stroke-dasharray: 126;
    stroke-dashoffset: 126;
    transform: rotate(-90deg);
    transform-origin: center;
    transition: stroke-dashoffset 0.3s ease;
    fill: none;
    filter: drop-shadow(0 0 1px #31DFDF);
}

.ai-progress::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    border: 3.5px solid #31DFDF;
    border-radius: 50%;
    opacity: 0.3;
}

.ai-arrow {
    stroke: #1599fc;
    stroke-width: 3.5;
    fill: none;
    transition: all 0.3s ease;
    animation: float 2s ease-in-out infinite;
    filter: drop-shadow(0 0 3px rgba(21, 153, 252, 0.8));
    stroke-linecap: round;
    stroke-linejoin: round;
}

.ai-back-to-top:hover .ai-circle {
    stroke: #43e794;
}

.ai-back-to-top:hover .ai-arrow {
    stroke: #43e794;
    transform: translateY(-5px);
    filter: drop-shadow(0 0 5px rgba(67, 231, 148, 0.8));
}

/* 水波纹动画 */
.ai-back-to-top::before,
.ai-back-to-top::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    border: 2px solid rgba(21, 153, 252, 0.3);
    border-radius: 50%;
    animation: ripple 2s cubic-bezier(0.23, 1, 0.32, 1) infinite;
    opacity: 0;
}

.ai-back-to-top.active::before {
    animation-delay: 0s;
}

.ai-back-to-top.active::after {
    animation-delay: 0.6s;
}

@keyframes ripple {
    0% {
        transform: scale(0.8);
        opacity: 0;
    }
    40% {
        opacity: 0.2;
    }
    100% {
        transform: scale(1.5);
        opacity: 0;
    }
}

@keyframes float {
    0% {
        transform: translateY(0);
        filter: drop-shadow(0 0 3px rgba(21, 153, 252, 0.8));
    }
    50% {
        transform: translateY(-5px);
        filter: drop-shadow(0 0 5px rgba(21, 153, 252, 0.8));
    }
    100% {
        transform: translateY(0);
        filter: drop-shadow(0 0 3px rgba(21, 153, 252, 0.8));
    }
}

.ai-back-to-top:hover::before,
.ai-back-to-top:hover::after {
    border-color: rgba(67, 231, 148, 0.3);
}