styles.css

:root {
    --primary-color: #3498db;
    --background-color: #0c0026ec;
    --button-color: #e74c3c;
    --button-hover-color: #c0392b;
    --text-color: #fff;
    --animation-duration: 1.8s;
    --fade-duration: 1.8s;
    /* 增加动画持续时间 */
}

#loadButton {
    padding: 15px 30px;
    font-size: 18px;
    cursor: pointer;
    background-color: var(--button-color);
    color: white;
    border: none;
    border-radius: 5px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    transition: background-color 0.3s, transform 0.3s;
}

#loadButton:hover {
    background-color: var(--button-hover-color);
    transform: scale(1.05);
}

#overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--background-color);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    visibility: hidden;
    opacity: 0;
    z-index: 1000;
    /* 确保覆盖页面内容 */
    transition: visibility 0s, opacity 0.5s;
}

#overlay.visible {
    visibility: visible;
    opacity: 1;
}

.loader {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100px;
    height: 100px;
}

.loader div {
    width: 20px;
    height: 20px;
    background-color: var(--primary-color);
    margin: 3px;
    border-radius: 50%;
    animation: bounce var(--animation-duration) infinite ease-in-out both;
}

.loader div:nth-child(1) {
    animation-delay: -0.32s;
}

.loader div:nth-child(2) {
    animation-delay: -0.16s;
}

@keyframes bounce {

    0%,
    80%,
    100% {
        transform: scale(0);
    }

    40% {
        transform: scale(1);
    }
}

#overlay p {
    margin-top: 20px;
    font-size: 24px;
    color: var(--text-color);
    animation: fadeIn var(--fade-duration) ease-in-out infinite;
}

@keyframes fadeIn {

    0%,
    100% {
        opacity: 0;
    }

    25%,
    75% {
        opacity: 1;
    }
}