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

body {
    font-family: "Segoe UI", "Helvetica Neue", sans-serif;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;

    /* 固定背景颜色：苹果绿 */
    background-color: #8BC34A; /* 你也可以用 #A8E063 等更亮一点的苹果绿 */
}

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

.welcome-box {
    text-align: center;
    background: rgba(0, 0, 0, 0.4);
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
}

.welcome-box h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.welcome-box p {
    font-size: 1.2rem;
    color: #ddd;
}