html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    overflow: hidden;
}

body {
    background: linear-gradient(
        120deg,
        #0b132b,
        #1c2541,
        #3a506b,
        #5bc0be
    );
    background-size: 400% 400%;
    animation: bgFlow 18s ease infinite;
}

@keyframes bgFlow {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

canvas {
    position: fixed;
    inset: 0;
    pointer-events: none; /* 🔥 关键：彻底解决鼠标卡顿 */
    z-index: -1;
}