css 雪花

 

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    overflow-x: hidden;
    transition: background-color 0.3s, color 0.3s;
    position: relative;
}

body::before {
    content: "❄️";
    position: fixed;
    top: -30px;
    left: 5%;
    font-size: 14px;
    opacity: 0;
    z-index: -1;
    pointer-events: none;
    animation: snowfall 4s linear infinite;
}

body::after {
    content: "❄️";
    position: fixed;
    top: -25px;
    left: 30%;
    font-size: 12px;
    opacity: 0;
    z-index: -1;
    pointer-events: none;
    animation: snowfall 5s linear infinite 1s;
}

body .snow-1 {
    content: "❄️";
    position: fixed;
    top: -20px;
    left: 55%;
    font-size: 16px;
    opacity: 0;
    z-index: -1;
    pointer-events: none;
    animation: snowfall 6s linear infinite 2s;
}

body .snow-2 {
    content: "❄️";
    position: fixed;
    top: -35px;
    left: 80%;
    font-size: 13px;
    opacity: 0;
    z-index: -1;
    pointer-events: none;
    animation: snowfall 4.5s linear infinite 0.5s;
}

body .snow-3 {
    content: "❄️";
    position: fixed;
    top: -15px;
    left: 15%;
    font-size: 11px;
    opacity: 0;
    z-index: -1;
    pointer-events: none;
    animation: snowfall 5.5s linear infinite 1.5s;
}

body .snow-4 {
    content: "❄️";
    position: fixed;
    top: -30px;
    left: 70%;
    font-size: 15px;
    opacity: 0;
    z-index: -1;
    pointer-events: none;
    animation: snowfall 4.8s linear infinite 2.5s;
}

@keyframes snowfall {
    0% {
        transform: translateY(0) translateX(0);
        opacity: 0;
    }

    10% {
        opacity: 0.8;
    }

    25% {
        transform: translateY(25vh) translateX(10px);
    }

    50% {
        transform: translateY(50vh) translateX(25px);
    }

    75% {
        transform: translateY(75vh) translateX(40px);
    }

    90% {
        opacity: 0.6;
    }

    100% {
        transform: translateY(100vh) translateX(60px);
        opacity: 0;
    }
}