body {
    font-family: 'M PLUS Rounded 1c', 'Noto Sans JP', sans-serif;
    line-height: 1.7;
}

@media (max-width: 768px) {
    .hero-header h1 {
        font-size: 1.3rem;
    }

    .container .xxxx {
        font-size: 2rem;
    }

    .hero-header h2 {
        font-size: 1.1rem;
    }

    h3 {
        font-size: 1.8rem;
    }

    .problems ul,
    .benefits ul {
        flex-direction: column;
    }

    .btn-primary,
    .btn-secondary,
    .btn-start {
        display: block;
        margin: 15px auto;
    }

    .free_plan .st {
        font-size: xx-large;
    }
}

.manga_base {
    --side-left: calc(2%);
    --side-right: calc(2%);
    position: absolute;

    width: -webkit-fill-available;
    margin: 1px;
}

.manga_title {
    text-align: center;
}

.manga_img {
    width: inherit;
}

.manga_l_div {
    position: inherit;
    width: 300px;
    left: var(--side-left);
    background-color: white;
    box-shadow: 0px 0px 8px rgba(0, 0, 0, 0.4);
}

.manga_r_div {
    position: inherit;
    width: 300px;
    right: var(--side-right);
    background-color: white;
    box-shadow: 0px 0px 8px rgba(0, 0, 0, 0.4);
}


@media (max-width: 1624px) {
    .manga_base {
        display: flex;
        align-content: anchor-center;
        width: fit-content;
        max-width: 960px;
        margin: 0 auto;
        padding: 0 20px;
        position: static;
    }

    .manga_title {
        font-size: small;
    }

    .manga_r_div {
        width: calc(100%);
        margin: 10px;
        background-color: white;
        box-shadow: 0px 0px 8px rgba(0, 0, 0, 0.4);
    }

    .manga_l_div {
        width: calc(100%);

        margin: 10px;
        background-color: white;
        box-shadow: 0px 0px 8px rgba(0, 0, 0, 0.4);
    }
}

.marker {

    background-color: #fffd82;

    padding: 2px 4px;

    display: inline;

    box-shadow: -2px 0 0 #fffd82, 2px 0 0 #fffd82;

    border-radius: 3px;
}

.main-header {
    background-color: #fff;
    border-bottom: 1px solid #ddd;
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.header-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header-logo {
    font-size: 1.6rem;
    font-weight: 700;
    color: #2c3e50;
    text-decoration: none;
}

.header-menu {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    gap: 25px;
    font-size: 1.0rem;
}

.header-menu a {
    text-decoration: none;
    color: #555;
    font-weight: 700;
    transition: color 0.3s ease;
}

.header-menu a:hover {
    color: #3498db;
}

@media (max-width: 768px) {
    .header-nav {
        flex-direction: column;
        gap: 15px;
    }

    .header-menu {
        flex-wrap: wrap;
        justify-content: center;
        gap: 15px;
    }
}


.new-tag {
    background-color: #fee2e2;
    color: #dc2626;
    font-size: 0.7rem;
    font-weight: bold;
    margin-left: 5px;
    padding: 2px 8px;
    border-radius: 9999px;
    text-transform: uppercase;
}

footer {
    background-color: #2c3e50;
    color: #bdc3c7;
    text-align: center;
    padding: 20px 0;
    font-size: 1rem;
}