#fireRainContainer {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100vh;
    overflow: hidden;
    pointer-events: none;
    z-index: 40; /* 可調整在角色前後 */
}

.fire-particle {
    position: absolute;
    top: -10vh;
    left: -10vw;

    /* 火焰形狀 */
    width: 2px;
    height: var(--h);

    /* 火焰顏色（核心） */
    background: linear-gradient(
        to bottom,
        rgba(255,255,200,0.9),
        rgba(255,160,0,0.9),
        rgba(255,40,0,0.6),
        rgba(0,0,0,0)
    );

    /* 發光 */
    box-shadow:
        0 0 6px rgba(255,120,0,0.8),
        0 0 14px rgba(255,60,0,0.6);

    opacity: 0;
    transform: rotate(-35deg);
    animation:
        fireFall var(--dur) linear infinite,
        fireFlicker 0.6s ease-in-out infinite;
}

/* 斜向移動（左上 → 右下） */
@keyframes fireFall {
    0% {
        transform: translate(-15vw, -15vh) rotate(-35deg);
        opacity: 0;
    }
    20% { opacity: 0.8; }
    80% { opacity: 0.8; }
    100% {
        transform: translate(130vw, 130vh) rotate(-35deg);
        opacity: 0;
    }
}

/* 火焰跳動 */
@keyframes fireFlicker {
    0%   { filter: brightness(1); }
    50%  { filter: brightness(1.5); }
    100% { filter: brightness(1); }
}