* {
    margin: 0;
    padding: 0;
}
.box {
    background: #ffffff;
}

/* 主要内容 */
main {
    box-sizing: border-box;
    background-color: #fff;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

main section {
    display: flex;
    align-items: center;
    justify-content: center;
}

main section h2 {
    font-family: Helvetica, Helvetica;
    font-weight: bold;
    font-size: 40px;
    color: #3f2f2f;
    line-height: 60px;
    letter-spacing: 1px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    text-align: center;
    margin: 60px 0;
}

/* 关于我们 */
.about-us {
    width: 100%;
    background: #ffffff;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 56px 160px;
    box-sizing: border-box;
    font-family: Helvetica;
    font-size: 18px;
    color: #555555;
    line-height: 40px;
}

.about-us h2 {
    font-family: Helvetica, Helvetica;
    font-weight: bold;
    font-size: 22px;
    color: #333333;
    line-height: 26px;
}

.about-us-button {
    display: flex;
    align-items: center;
    justify-content: center;
    background: url("../../images/about-us-button.png") no-repeat center center;
    background-size: cover;
    width: 100%;
    padding: 15px;
    margin-top: 40px;
    font-family: Helvetica;
    font-size: 18px;
    color: #ffffff;
    line-height: 34px;
    box-sizing: border-box;
}
.about-us-button img {
    width: 86px;
    height: 67px;
    margin-right: 10px;
}

.abouts-us-subtitle {
    font-family: Helvetica;
    font-size: 18px;
    color: #333333;
    line-height: 26px;
    letter-spacing: 1px;
    margin: 20px 0;
}
.about-us-text {
    font-family: Helvetica;
    font-size: 18px;
    color: #555555;
    line-height: 40px;
    text-align: center;
}

/* 响应式适配：小屏幕下堆叠排列 */
@media (max-width: 768px) {
    /* Header响应式优化 */
    header {
        padding: 0 15px;
        height: auto;
        min-height: 70px;
    }

    header .left img {
        width: 50px;
        height: 40px;
        margin-right: 10px;
    }

    header .left h1 {
        font-size: 14px;
        line-height: 16px;
        max-width: 200px;
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
    }

    header .right .phone {
        margin-right: 10px;
    }

    header .right .phone img {
        width: 18px;
        height: 18px;
        margin-right: 5px;
    }

    header .right .phone p {
        font-size: 12px;
        line-height: 14px;
    }

    header .right .language img {
        width: 18px;
        height: 18px;
        margin-right: 5px;
    }

    header .right .language p {
        width: 30px;
        height: 25px;
        font-size: 12px;
        line-height: 20px;
        margin-right: 5px;
    }

    /* Nav响应式优化 */
    nav {
        height: auto;
        padding: 10px 0;
    }

    nav ul {
        width: 95%;
        flex-wrap: wrap;
    }

    nav ul li a {
        margin-right: 15px;
        margin-bottom: 5px;
        font-size: 14px;
    }

    /* About-us-tag响应式优化 - 中等屏幕 */
    .about-us {
        padding: 40px 20px;
    }

    /* Explore-box响应式优化 - 中等屏幕 */
    .explore-box {
        padding: 20px 40px;
    }

    .explore-box h2 {
        font-size: 20px;
        margin-bottom: 30px;
    }

    /* Footer响应式优化 */
    .footer-container {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }

    .footer-brand {
        margin-bottom: 20px;
    }
}

/* 超小屏幕适配 */
@media (max-width: 500px) {
    header .left h1 {
        max-width: 120px;
        font-size: 12px;
    }

    header .right .phone {
        display: none; /* 在极小屏幕隐藏电话号码 */
    }

    nav ul {
        width: 100%;
        justify-content: space-around;
    }

    nav ul li a {
        margin-right: 5px;
        font-size: 12px;
    }
    .choose-us {
        margin: 30px 0;
    }

    .choose-us h2 {
        font-size: 18px;
        line-height: 22px;
    }
}