.usonic-logo-wrapper {
    min-height: 80vh;
    margin: 0 auto;
    display: flex;
    justify-content: center;
    align-items: center;
    max-width: 60%;
}

.icon-wrapper img {
    max-width: 70px;
}

.manual-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    color: #39a953;
}

.page-content {
    max-width: 90%;
    margin: 0 auto;
    border: 1px solid #39a953;
    margin-bottom: 20px;
    padding: 20px;
}

.step-wrapper,
.specification-wrapper {
    display: flex;
    flex-direction: column;
    align-items: start;
    justify-content: start;
}

.step-img-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 20px auto;
    width: 100%;
}

.step-img-wrapper img {
    max-width: 60%;
}

.step-title,
.specification-title {
    font-size: var(--step-title-size);
    color: var(--primary-color);
    margin-bottom: 60px;
}

.step-subtitle,
.specification-subtitle {
    font-size: var(--step-subtitle-size);
    color: var(--primary-color);
    margin-bottom: 20px;
}

.step-description-wrapper {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    column-gap: 40px;
    margin-top: 60px;
}

.device-item-group {
    display: flex;
    flex-direction: column;
    align-items: start;
    justify-content: start;
}

.device-item {
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: start;
    gap: 10px;
    margin-bottom: 10px;
}

.item-no {
    border: 1px solid #000;
    border-radius: 50%;
    width: 16px;
    height: 16px;
    display: flex;
    justify-content: center;
    padding: 4px;
    align-items: center;
    font-size: var(--description-size);
}

/* new main frame */
.device-wrapper {
    display: flex;
    align-items: flex-start;
    gap: 20px;
}

.label-col {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: end;
    gap: 38px;
    margin-top: 100px;
}

.tag-row {
    position: relative;
    font-size: 18px;
    color: #333;
    padding-left: 100px;
}

.img-col img {
    height: 650px;
    /* 高度你可调 → 标签会永远贴着它 */
}



/*  */

.image-text {
    position: absolute;
    top: 114px;
    left: 27px;
    display: flex;
    flex-direction: column;
    gap: 50px;
    align-items: end;
}

.frame-description {
    margin-top: 40px;
    font-size: var(--description-size);
}


/* page 3 */
.frame-content {
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: center;
    margin: 20px auto;
}

.frame-wrapper {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 60px;
}

.navigation-wrapper {
    grid-template-columns: repeat(3, 1fr);
}

.frame-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    flex: 1;
    min-width: 0;
    text-align: center;
    gap: 12px;
    justify-content: start;
}

.frame-img {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
}

.frame-img img {
    /* max-width: 320px; */
    max-height: 480px;
    object-fit: contain;
    width: 100%;
}

.frame-img .navigation-img {
    max-height: 380px;
}

.frame-text-block {
    display: flex;
    flex-direction: column;
    gap: 8px;
    align-items: start;
    text-align: left;
}

.frame-title {
    position: relative;
}


.frame-text-block .frame-text-desc {
    text-align: left;
    font-size: var(--description-size);
}

.frame-text-block .frame-text-desc>p {
    margin: 0;
    white-space: nowrap;
    word-break: keep-all;
}

/* promt-wrapper */

.promt-wrapper {
    display: flex;
    flex-direction: column;
    align-items: start;
    justify-content: start;
    gap: 20px;
    margin: 40px auto;
    max-width: 80%;
}

/* specification */
.product-list {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    margin: 40px 0;
    /* max-width: 900px;
    margin: 0 auto; */
}

.product-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.product-img {
    width: 100px;
    height: 100px;
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 10px;
}

.product-img img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.item-name {
    font-size: var(--description-size);
    text-align: center;
    white-space: nowrap;
}

h4.table-name {
    color: #39a953;
    margin: 20px 0;
}

.spec-table {
    width: 100%;
    table-layout: fixed;
    border-collapse: collapse;
    font-size: var(--description-size);
    color: #000;
}

.spec-table td {
    width: 50%;
    border: 1px solid #000;
    padding: 5px 6px;
    vertical-align: middle;
    word-break: break-word;
}

.spec-table .highlight {
    font-weight: bold;
}

/* warning */
.warning-box {
    max-width: 800px;
    margin: 0 auto;
    font-family: sans-serif;
    color: #333;
    font-size: var(--description-size);
}

.warning-content {
    margin-bottom: 30px;
}

.warning-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
}

.warning-img img {
    width: 24px;
    height: 24px;
}

.warning-title {
    font-size: var(--step-title-size);
    color: var(--primary-color);
    font-weight: bold;
}

.warning-sub-title {
    font-size: var(--description-size);
    color: var(--primary-color);
    font-weight: bold;
    margin: 20px 0;
}

.icon-title {
    font-size: var(--step-subtitle-size);
    font-weight: bold;
}

.warning-paragraph {
    margin-bottom: 10px;
}

.warning-list {
    padding-left: 20px;
    list-style: disc;
}

/* battery-info */
.battery-disposal {
    min-height: 800px;
    display: flex;
    flex-direction: column;
    align-items: start;
    justify-content: space-between;
}

.battery-content {
    margin: 40px 0;
}

.used-batteries {
    margin: 40px 0;
}

.used-batteries h4,
.leak-battries h4 {
    font-size: var(--description-size);
    margin-bottom: 10px;
}

.used-batteries>p,
.leak-battries>p,
.manufacture-wrapper {
    font-size: var(--description-size);
}

.text-indent {
    text-indent: 1.5em;
}

.battery-notice {
    margin: 20px 0;
    font-size: var(--description-size);
}

.cerification-icon img {
    max-width: 220px;
}

#englishContent .certification-wrapper {
    margin: 40px 0;
}

#englishContent .image-text {
    position: absolute;
    top: 140px;
    left: 18px;
    display: flex;
    flex-direction: column;
    gap: 62px;
    align-items: end;
}

/* video */
#chineseContent .usonic-logo-wrapper {
    min-height: 20vh;
}

#chineseContent .manual-wrapper {
    padding-top: 40px;
}

.video-wrapper {
    position: relative;
    max-width: 90%;
    margin: 80px auto;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
    font-size: 0;
    border-radius: 10px;
    overflow: hidden;
    cursor: pointer;
}

.video-wrapper video {
    width: 100%;
    height: auto;
    display: block;
}

.video-cover {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 5;
    transition: opacity 0.3s ease;
}

.video-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.play-btn {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: rgba(0, 0, 0, 0.8);
    border: none;
    width: 80px;
    height: 80px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    z-index: 10;
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

.play-btn:hover {
    background: rgba(20 20 20, 1);
    transform: translate(-50%, -50%) scale(1.1);
}

.video-wrapper.playing .video-cover {
    opacity: 0;
    pointer-events: none;
}

.video-wrapper.playing .play-btn {
    opacity: 0.7;
    background: rgba(0, 0, 0, 0.6);
    transform: translate(-50%, -50%) scale(0.8);
}

.video-wrapper.playing .play-btn svg {
    transform: scale(0.8);
}

.video-wrapper.controls-hidden .play-btn {
    opacity: 0;
    pointer-events: none;
    transform: translate(-50%, -50%) scale(0.6);
}

/* back to top */
.back-to-top {
    position: fixed;
    right: 28px;
    bottom: 35px;
    width: 48px;
    height: 48px;
    background: #39a953;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity .4s ease, transform .3s ease;
    z-index: 999;
}

.back-to-top svg {
    width: 22px;
    height: 22px;
    fill: #fff;
}

/* 出现 */
.back-to-top.show {
    opacity: 1;
    pointer-events: auto;
}

/* hover 动效 */
.back-to-top:hover {
    transform: scale(1.12);
}

@media (max-width: 768px) {
    .content {
        max-width: 100%;
        padding: 0 8px;
    }

    .tabs {
        max-width: 100%;
    }

    .page-content {
        max-width: 100%;
        padding: 10px;
    }

    .product-list {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
        width: 100%;
    }

    /* back to top */
    .back-to-top {
        width: 54px;
        height: 54px;
        bottom: calc(20px + env(safe-area-inset-bottom));
        right: 15px;
        border-radius: 50%;
        box-shadow: 0 4px 12px rgba(0, 0, 0, .25);
    }

    .back-to-top svg {
        width: 25px;
        height: 25px;
    }

    .back-to-top:hover {
        transform: none;
        /* 移动端禁用hover */
    }

    .frame-wrapper {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
        padding: 8px;
    }

    .frame-img img,
    .frame-img .navigation-img {
        max-height: 260px;
        width: 100%;
    }

    .frame-group {
        gap: 14px;
    }

    .frame-title {
        font-size: 16px;
        margin-top: 12px;
    }

    .frame-title.min-h{
        min-height: 48px;
    }

    .frame-title::before {
        left: -12px;
    }

    .frame-text-block .frame-text-desc>p {
        white-space: normal;
        word-break: break-word;
        font-size: 13px;
        line-height: 1.5;
    }

    .step-description-wrapper {
        gap: 20px;
    }

    .step-img-wrapper img {
        max-width: 90%;
    }

    .label-col {
        gap: 20px;
    }

    .tag-row {
        padding-left: 0;
        font-size: 16px;
    }
}


@media (max-width: 480px) {
    :root{
        --step-title-size: 20px;
        --step-subtitle-size: 16px;
        --description-size: 12px;
    }

    .device-item{
        gap: 8px;
    }

    .tag-row{
        font-size: 14px;
    }

}