/* 启动页层，覆盖在 app 上 */
#splash {
    position: fixed;
    inset: 0; 
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #ffffff; /* 与 manifest background_color 一致 */
    z-index: 9999;
    flex-direction: column;
}
.splash-content{
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}
/* logo */
.splash-content img {
    width: 100px;
    height: 100px;
    margin-bottom: 20px;
}

/* loading spinner */
.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #007aff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 渐隐动画 */
.fade-out {
    animation: fadeOut 0.5s forwards;
}

@keyframes fadeOut {
    to { opacity: 0; visibility: hidden; }
}