.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: #fff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    z-index: 1000;
}
.header-inner {
    max-width: 90%;
    margin: 0 auto;
    padding: 10px 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.site-logo {
    margin: 0;
    width: 120px;
}
@media (max-width: 1200px) {
    .site-logo {
        margin: 0;
        width: 80px;
    }
}
.site-logo a {
    text-decoration: none;
}
.site-logo a img{
    width: 100%;
}
.nav-menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
}
@media (max-width: 1200px) {
    .nav-menu {
        display: block;
        position: fixed;
        top: 0;
        right: -300px;
        width: 300px;
        height: 100vh;
        background: #fff;
        padding: 80px 30px 30px;
        box-shadow: -2px 0 4px rgba(0,0,0,0.1);
        transition: transform 0.3s ease;
        overflow-y: auto;
    }
}
.nav-menu a {
    text-decoration: none;
    color: #333;
    position: relative;  /* 下線のための位置基準 */
    display: block;
    padding:0 25px;
    border-left: 1px solid #ddd;
    text-align: center;
}
@media screen and (max-width: 1200px) {
    .nav-menu a {
        border-left: 0;
    }
}
.jp-nav-menu-item {
    font-size: 15px;
    margin-bottom: 2px;
}
.en-nav-menu-item {
    font-size: 12px;
    color: #666;
}
.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -20px;
    left: 50%;  /* 中心から開始 */
    transform: translateX(-50%);  /* 中心位置を調整 */
    width: 0;
    height: 2px;
    background: #333;
    transition: width 0.3s ease;
}
@media screen and (max-width: 1200px) {
    .nav-menu a::after {
        height: 1px;
        bottom: -5px; 
    }
}
.nav-menu a:hover::after {
    width: 100%;
}
.nav-menu a .jp-nav-menu-item {
    font-size: 1.3rem;
}
.nav-menu a .en-nav-menu-item {
    font-size: 1rem;
    font-family: 'Outfit', sans-serif;
    letter-spacing: 0.15em;
}
.nav-menu li:last-child a{
    border-right: 1px solid #ddd;
}
@media screen and (max-width: 1200px) {
    .nav-menu li:last-child a{
        border-right: 0;
        margin-bottom: 0;
    }
}
@media (max-width: 1200px) {
    .nav-menu.active {
        transform: translateX(-300px);
    }
    .nav-menu li:first-child {
        border-top: 1px solid #ddd;
    }
    .nav-menu li {
        padding: 20px 0;
        border-bottom: 1px solid #ddd;
    }
}
.hamburger {
    display: none;
    border: none;
    background: none;
    cursor: pointer;
    padding: 0;
    width: 30px;
    height: 20px;
    position: relative;
    z-index: 1001;
}
@media (max-width: 1200px) {
    .hamburger {
        display: block;
    }
}
.hamburger span {
    display: block;
    width: 100%;
    height: 1px;
    background-color: #333;
    position: absolute;
    transition: all 0.3s;
}
.hamburger span:nth-child(1) { top: 0; }
.hamburger span:nth-child(2) { top: 9px; }
.hamburger span:nth-child(3) { bottom: 0; }
@media (max-width: 979px) {
    .hamburger.active span:nth-child(1) {
        transform: rotate(45deg);
        top: 9px;
    }
    .hamburger.active span:nth-child(2) {
        opacity: 0;
    }
    .hamburger.active span:nth-child(3) {
        transform: rotate(-45deg);
        bottom: 9px;
    }
}