/* 白色拟态主题 - 底部样式 */

/* ========== CSS变量定义（与header.css保持一致） ========== */
:root {
    --background-color: #ebecf0;
    --greyLight-1: #e4ebf5;
    --greyLight-2: #c8d0e7;
    --greyLight-3: #bec8e4;
    --greyDark: #6d85c1;
    --white: #fff;
    --text-a-color: #7a7e90;
    --text-a-hover: #8897d8;
    --text-li-color: #565e82;
    --primary: #6d5dfc;
    --primary-dark: #5b0eeb;
}

/* ========== 底部样式 ========== */
.footer {
    background: var(--background-color);
    color: var(--text-li-color);
    padding: 30px 0;
    box-shadow: inset 0 0.1rem 0.2rem var(--greyLight-2);
}

.footer-container {
    max-width: 2000px;
    margin: 0 auto;
    padding: 0 20px;
}

.footer-bottom {
    text-align: center;
}

.copyright {
    color: var(--text-a-color);
    font-size: 14px;
}

.beian-link {
    color: var(--text-a-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

.beian-link:hover {
    color: var(--primary);
}

/* ========== 返回顶部按钮 ========== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--background-color);
    color: var(--primary);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    box-shadow: 0.2rem 0.2rem 0.4rem var(--greyLight-2), -0.1rem -0.1rem 0.3rem var(--white);
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
}

.back-to-top svg {
    width: 28px;
    height: 28px;
}

.back-to-top svg path {
    fill: var(--primary);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: 0.3rem 0.3rem 0.6rem var(--greyLight-2), -0.2rem -0.2rem 0.5rem var(--white);
}

.back-to-top:active {
    box-shadow: inset 0.2rem 0.2rem 0.4rem var(--greyLight-2), inset -0.1rem -0.1rem 0.3rem var(--white);
    transform: translateY(-3px);
}

/* ========== 响应式设计 ========== */
@media (max-width: 768px) {
    .footer {
        padding: 20px 0;
    }

    .footer-container {
        padding: 0 5%;
    }

    .copyright {
        font-size: 12px;
        line-height: 1.6;
        text-align: center;
    }

    .beian-link {
        font-size: 12px;
    }

    .back-to-top {
        width: 44px;
        height: 44px;
        bottom: 20px;
        right: 15px;
        box-shadow: 0.2rem 0.2rem 0.4rem var(--greyLight-2), -0.1rem -0.1rem 0.3rem var(--white);
    }

    .back-to-top svg {
        width: 24px;
        height: 24px;
    }

    .back-to-top:hover {
        transform: translateY(-3px);
        box-shadow: 0.3rem 0.3rem 0.6rem var(--greyLight-2), -0.2rem -0.2rem 0.5rem var(--white);
    }
}