html {
    scroll-behavior: smooth;
}

.product-intro {
    background-color: #E5E5EA;
    font-family: 'IBM Plex Sans JP', sans-serif;
}

.product-intro__header {
    background-color: var(--name-bg, var(--brand-color, #FFD700));
    height: 111px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.product-intro__name {
    font-size: 48px;
    font-weight: 700;
    line-height: 60px;
    color: var(--name-color, #000);
    margin: 0;
    text-align: center;
}

.product-intro__container {
    position: relative;
    display: flex;
    align-items: stretch;
    background-color: #fff;
    min-height: 600px;
}

.product-intro__image {
    width: 55%;
    flex-shrink: 0;
    position: relative;
    overflow: hidden;
}

.product-intro__image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    aspect-ratio: 4 / 3;
    display: block;
}

.product-intro__image .product-intro__image--sp {
    display: none;
}

.product-intro__content {
    flex: 1;
    padding: 90px 80px;
    display: flex;
    flex-direction: column;
    background-color: var(--intro-bg, #fff);
}

.product-intro__inner {
    width: 100%;
}

.product-intro__title {
    font-size: 32px;
    font-weight: 700;
    line-height: 48px;
    color: var(--intro-color, #000);
    margin: 0 0 50px;
}

.product-intro__description {
    font-size: 18px;
    line-height: 39px;
    font-weight: 450;
    color: var(--intro-color, #333);
    text-align: justify;
}

.product-intro__description p {
    margin: 0 0 20px;
}

.product-intro__description p:last-child {
    margin-bottom: 0;
}

.brand-nav {
    width: 100%;
    height: 90px;
    background-color: var(--nav-bg-color, #000);
    position: relative;
    display: flex;
    align-items: center;
    z-index: 100;
}

.brand-nav--fixed {
    position: fixed;
    top: -90px;
    left: 0;
    width: 100%;
    transition: top 0.35s ease;
    z-index: 999;
}

.brand-nav--fixed.brand-nav--visible {
    top: 0;
}

.brand-nav__container {
    width: 100%;
    display: flex;
    justify-content: space-between;
    gap: 0;
    align-items: center;
    padding: 0 195px;
    height: 60px;
}

/* 5 items */
.brand-nav__container:has(.brand-nav__item:nth-child(5)):not(:has(.brand-nav__item:nth-child(6))) {
    padding: 0 125px;
}

/* 6+ items */
.brand-nav__container:has(.brand-nav__item:nth-child(6)) {
    padding: 0 125px;
}

.brand-nav__item {
    color: var(--nav-text-color, #fff);
    font-family: 'Roboto Flex', sans-serif;
    font-size: 18px;
    font-weight: 600;
    text-decoration: none;
    transition: color 0.3s;
}

.brand-nav__item--active {
    color: var(--brand-color, #FFD700);
}

@media (hover: hover) {
    .brand-nav__item:hover {
        color: var(--brand-color, #FFD700);
    }
}

@media (max-width: 1025px) and (min-width: 768px) {
    .product-intro__header {
        height: 60px;
    }

    .product-intro__name {
        font-size: 36px;
        line-height: 60px;
    }

    .product-intro__container {
        min-height: 500px;
    }

    .product-intro__image {
        width: 60%;
    }

    .product-intro__content {
        padding: 100px 30px 40px;
    }

    .product-intro__title {
        font-size: 18px;
        line-height: 1.3;
        margin-bottom: 25px;
        word-break: break-all;
        text-wrap: wrap;
    }

    .product-intro__description {
        font-size: 14px;
        font-weight: 500;
        line-height: 27px;
        word-break: break-all;
        text-wrap: wrap;
    }

    .product-intro__description p {
        word-break: break-all;
        text-wrap: wrap;
    }

    .brand-nav {
        height: 70px;
    }

    .brand-nav--fixed {
        top: -70px;
    }

    .brand-nav__container {
        width: 100%;
        padding: 0 115px;
        justify-content: space-between;
        gap: 0;
    }

    .brand-nav__container:has(.brand-nav__item:nth-child(5)):not(:has(.brand-nav__item:nth-child(6))) {
        padding: 0 45px;
    }

    .brand-nav__container:has(.brand-nav__item:nth-child(6)) {
        padding: 0 45px;
    }

    .brand-nav__item {
        font-size: 15px;
        font-weight: 600;
    }
}

@media (max-width: 768px) {
    .product-intro__header {
        height: 45px;
    }

    .product-intro__name {
        font-size: 18px;
        line-height: 1.2;
    }

    .product-intro__container {
        flex-direction: column;
        padding-bottom: 200px;
        min-height: auto;
        background-color: var(--brand-color, #FFD700);
    }

    .product-intro__image {
        width: 100%;
        height: auto;
    }

    .product-intro__image .product-intro__image--pc {
        display: none;
    }

    .product-intro__image .product-intro__image--sp {
        display: block;
        aspect-ratio: 3 / 4;
    }

    .product-intro__image img {
        height: auto;
    }

    .product-intro__content {
        position: absolute;
        bottom: 0;
        right: 0;
        width: 90%;
        max-width: 380px;
        padding: 55px 45px;
        aspect-ratio: 1 / 1;
        background-color: var(--intro-bg, #fff);
        box-sizing: border-box;
    }

    .product-intro__title {
        font-size: 18px;
        line-height: 1.5;
        margin-bottom: 20px;
    }

    .product-intro__description {
        font-size: 14px;
        line-height: 1.8;
        word-break: break-all;
        text-wrap: wrap;
    }

    .product-intro__description p {
        margin-bottom: 15px;
        word-break: break-all;
        text-wrap: wrap;
    }

    .brand-nav__container,
    .brand-nav__container:has(.brand-nav__item:nth-child(4)):not(:has(.brand-nav__item:nth-child(5))),
    .brand-nav__container:has(.brand-nav__item:nth-child(5)):not(:has(.brand-nav__item:nth-child(6))),
    .brand-nav__container:has(.brand-nav__item:nth-child(6)) {
        width: 100%;
        flex-wrap: wrap;
        height: auto;
        padding: 10px;
        gap: 5px;
        justify-content: space-between;
        margin: 0;
    }

    /* 3 items only: auto spacing */
    .brand-nav__container:has(.brand-nav__item:nth-child(3)):not(:has(.brand-nav__item:nth-child(4))) {
        gap: 0;
        padding-left: 50px;
        padding-right: 50px;
    }

    .brand-nav__item {
        font-size: 12px;
    }
}