.site-header {
    background-color: #fff;
    margin: 1em 2.5%;
    width: 95vw;
    border-radius: 5px;
    padding: 20px 30px;
    position: absolute;
    z-index: 1000;
    vertical-align: baseline;
}

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

.logo img {
    height: 50px;
}

/* ナビゲーション */
.main-nav ul {
    list-style: none;
    display: flex;
    gap: 1.5rem;
}

.main-nav a {
    position: relative;
    text-decoration: none;
    color: #00A876;
    font-size: 1.2rem;
    padding: 4px 6px;
}

.main-nav a::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -4px;
    width: 0%;
    height: 2px;
    background: #00A876;
    transition: width 0.3s ease;
}

.main-nav a:hover::after {
    width: 100%;
}

.menu-toggle {
    display: none;
    font-size: 2rem;
    color: #00A876;
    cursor: pointer;
}




@media (max-width: 768px) {
    .site-header {
        padding: 10px 20px;
    }

    .container {
        display: flex;
        flex-wrap: wrap;
        justify-content: space-between;
        align-items: center;
    }

    .logo {
        display: flex;
        align-items: center;
        justify-content: space-between;
        width: auto;
    }

    .logo img {
        height: 35px;
        width: auto;
    }

    .menu-toggle {
        display: block;
        margin-left: 20px;
        order: 0;
    }

    .main-nav {
        width: 100%;
        order: 1;
        margin-top: 10px;
    }

    .main-nav ul {
        display: none;
        flex-direction: column;
        width: 100%;
        padding: 0;
        margin: 0;
    }

    .main-nav.active ul {
        display: flex;
    }

    .main-nav a {
        display: block;
        padding: 12px 0;
        border-bottom: 1px solid #f0f0f0;
    }

    .main-nav a::after {
        display: none;
    }

    .menu-toggle i {
        transition: transform 0.3s ease;
    }

    .menu-toggle.active i {
        transform: rotate(180deg);
    }

}