*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
    background-color: #f5f5f5;
    color: #333;
    line-height: 1.6;
}

/* Mobile Header */
.mobile-header {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background-color: #fff;
    border-bottom: 1px solid #e0e0e0;
    z-index: 1000;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px;
    box-sizing: border-box;
}

.mobile-header-title {
    font-size: 19px;
    font-weight: 600;
    color: #333;
    position: relative;
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    text-decoration: none;
}

.mobile-header-title-icon {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    object-fit: cover;
}

.mobile-header-title span {
    position: relative;
}

.mobile-header-title span::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 100%;
    height: 1px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 2px;
}

.container {
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 240px;
    background-color: #fff;
    border-right: 1px solid #e0e0e0;
    padding: 24px 16px;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    box-sizing: border-box;
}

.sidebar-header {
    display: flex;
    align-items: center;
    margin-bottom: 32px;
    padding-bottom: 16px;
    border-bottom: 1px solid #e0e0e0;
}

.avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    margin-right: 12px;
    overflow: hidden;
    flex-shrink: 0;
}

.avatar-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
}

.user-info h3 {
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 2px;
}

.user-info p {
    font-size: 13px;
    color: #666;
}

.nav-menu {
    list-style: none;
}

.nav-menu li {
    margin-bottom: 4px;
}

.nav-menu a {
    display: flex;
    align-items: center;
    padding: 10px 12px;
    color: #333;
    text-decoration: none;
    font-size: 15px;
    border-radius: 4px;
    transition: background-color 0.2s;
}

.nav-menu a:hover {
    background-color: #f5f5f5;
}

.nav-menu a.active {
    background-color: #f0f0f0;
    font-weight: 500;
}

.nav-icon {
    width: 20px;
    height: 20px;
    margin-right: 12px;
    opacity: 0.7;
}

/* Footer Navigation */
.footer-nav {
    display: none;
}

@media (max-width: 768px) {
    .footer-nav {
        display: block;
        margin-top: 48px;
        padding: 0;
        border-top: 1px solid #e0e0e0;
    }
}

.footer-nav-menu {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-nav-menu li {
    margin: 0;
    border-bottom: 1px solid #e0e0e0;
}

.footer-nav-menu li:first-child {
    border-top: 1px solid #e0e0e0;
}

.footer-nav-menu a {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 20px;
    color: #333;
    text-decoration: none;
    font-size: 15px;
    background-color: #fafafa;
    transition: background-color 0.2s;
}

.footer-nav-menu a:hover {
    background-color: #f5f5f5;
}

.footer-nav-menu a.active {
    background-color: #f0f0f0;
    font-weight: 500;
}

.footer-nav-menu a span {
    flex: 1;
}

.footer-nav-arrow {
    width: 20px;
    height: 20px;
    opacity: 0.5;
    flex-shrink: 0;
}

.footer-copyright {
    text-align: center;
    padding: 20px;
    color: #999;
    font-size: 13px;
    border-top: 1px solid #e0e0e0;
}

.footer-copyright p {
    margin: 0;
}

/* Mobile Menu Toggle */
.menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    width: 32px;
    height: 24px;
    background: none;
    border: none;
    padding: 0;
    cursor: pointer;
    box-shadow: none;
    position: relative;
    outline: none;
}

.menu-toggle:focus {
    outline: none;
}

.hamburger-line {
    display: block;
    width: 100%;
    height: 3px;
    min-height: 3px;
    background-color: #333 !important;
    border-radius: 2px;
    transition: all 0.3s ease;
    margin-top: 6px;
    flex-shrink: 0;
}

.hamburger-line:first-child {
    margin-top: 0;
}

.menu-toggle:hover .hamburger-line {
    background-color: #666;
}

.menu-toggle:active .hamburger-line {
    background-color: #999;
}

/* ハンバーガーメニューが開いている時の×マーク */
.menu-toggle.active {
    position: relative;
}

.menu-toggle.active .hamburger-line-1 {
    position: absolute;
    top: 50%;
    left: 50%;
    margin: 0;
    transform: translate(-50%, -50%) rotate(45deg);
    background-color: #333 !important;
    height: 3px;
    min-height: 3px;
}

.menu-toggle.active .hamburger-line-2 {
    display: none;
}

.menu-toggle.active .hamburger-line-3 {
    position: absolute;
    top: 50%;
    left: 50%;
    margin: 0;
    transform: translate(-50%, -50%) rotate(-45deg);
    background-color: #333 !important;
    height: 3px;
    min-height: 3px;
}

/* Sidebar Overlay */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 999;
}

.sidebar-overlay.active {
    display: block;
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: 240px;
    padding: 32px;
}

.page-title {
    font-size: 25px;
    font-weight: 600;
    color: #333;
    margin-bottom: 24px;
}

/* YouTube Link Button */
.youtube-link-button {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    background-color: #fff;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    color: #333;
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    margin-bottom: 24px;
    transition: all 0.2s;
}

.youtube-link-button:hover {
    background-color: #f5f5f5;
    border-color: #d0d0d0;
}

.youtube-icon {
    width: 20px;
    height: 20px;
    fill: #FF0000;
}

/* Portfolio Grid */
.portfolio-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 24px;
}

.portfolio-item {
    background-color: #fff;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    overflow: hidden;
    transition: box-shadow 0.2s;
    cursor: pointer;
}

.portfolio-item:hover {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.portfolio-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background-color: #f0f0f0;
}

.portfolio-content {
    padding: 16px;
}

.portfolio-title {
    font-size: 17px;
    font-weight: 600;
    margin-bottom: 8px;
    color: #333;
}

.portfolio-description {
    font-size: 15px;
    color: #666;
    line-height: 1.5;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.9);
    overflow: auto;
}

.modal-content {
    background-color: #fff;
    margin: 5% auto;
    padding: 0;
    border-radius: 4px;
    width: 90%;
    max-width: 900px;
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

    .modal-close {
    position: absolute;
    top: 16px;
    right: 16px;
    color: #fff;
    font-size: 29px;
    font-weight: bold;
    cursor: pointer;
    z-index: 1001;
    background-color: rgba(0, 0, 0, 0.5);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s;
}

@media (max-width: 480px) {
    .modal-close {
        top: 12px;
        right: 12px;
        width: 36px;
        height: 36px;
        font-size: 24px;
    }
}

.modal-close:hover {
    background-color: rgba(0, 0, 0, 0.7);
}

.modal-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background-color: rgba(0, 0, 0, 0.5);
    color: #fff;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 1001;
    transition: background-color 0.2s;
    padding: 0;
}

.modal-nav:hover {
    background-color: rgba(0, 0, 0, 0.7);
}

.modal-nav svg {
    width: 24px;
    height: 24px;
}

.modal-nav-prev {
    left: calc((100% - 90%) / 2 - 50px);
}

.modal-nav-next {
    right: calc((100% - 90%) / 2 - 50px);
}

@media (max-width: 1024px) {
    .modal-nav-prev {
        left: 8px;
    }
    
    .modal-nav-next {
        right: 8px;
    }
}

.modal-nav:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

.modal-nav:disabled:hover {
    background-color: rgba(0, 0, 0, 0.5);
}

.modal-image {
    width: 100%;
    max-height: 70vh;
    object-fit: contain;
    background-color: #000;
}

.modal-body {
    padding: 24px;
}

.modal-title {
    font-size: 21px;
    font-weight: 600;
    margin-bottom: 12px;
    color: #333;
}

.modal-description {
    font-size: 15px;
    color: #666;
    line-height: 1.6;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 64px 24px;
    background-color: #fff;
    border-radius: 4px;
    border: 1px solid #e0e0e0;
}

.empty-state h3 {
    font-size: 19px;
    font-weight: 600;
    margin-bottom: 8px;
    color: #333;
}

.empty-state p {
    font-size: 15px;
    color: #666;
}

/* Responsive */
@media (max-width: 1024px) {
    .portfolio-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
        gap: 16px;
    }
}

@media (max-width: 768px) {
    .mobile-header {
        display: flex;
    }
    
    .menu-toggle {
        display: block;
    }
    
    .main-content {
        padding-top: 76px;
    }
    
    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.3s ease;
        z-index: 1000;
        width: 280px;
        padding: 24px 16px;
        box-sizing: border-box;
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .sidebar-header {
        padding-left: 0;
        padding-right: 0;
        margin-left: 0;
        margin-right: 0;
    }
    
    .nav-menu {
        padding-left: 0;
        margin-left: 0;
    }
    
    .nav-menu li {
        width: 100%;
    }
    
    .nav-menu a {
        width: 100%;
        padding: 12px 16px;
        box-sizing: border-box;
    }
    
    .main-content {
        margin-left: 0;
        padding: 16px;
        padding-top: 76px;
    }
    
    .footer-nav {
        display: block;
        margin-top: 32px;
    }
    
    .footer-nav-menu a {
        padding: 18px 16px;
        font-size: 14px;
    }
    
    .footer-nav-arrow {
        width: 18px;
        height: 18px;
    }
    
    .page-title {
        font-size: 21px;
        margin-bottom: 16px;
    }
    
    .youtube-link-button {
        padding: 10px 16px;
        font-size: 14px;
        margin-bottom: 16px;
    }
    
    .youtube-icon {
        width: 18px;
        height: 18px;
    }
    
    .portfolio-grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .portfolio-image {
        height: 180px;
    }
    
    .modal-content {
        width: 95%;
        margin: 10% auto;
    }
    
    .modal-image {
        max-height: 50vh;
    }
    
    .modal-body {
        padding: 16px;
    }
    
    .modal-title {
        font-size: 19px;
    }
    
    .modal-nav {
        width: 40px;
        height: 40px;
    }
    
    .modal-nav svg {
        width: 20px;
        height: 20px;
    }
    
    .modal-nav-prev {
        left: 8px;
    }
    
    .modal-nav-next {
        right: 8px;
    }
    
    .modal-content {
        width: 95%;
    }
    
    .sidebar-overlay.active {
        display: block;
    }
}

@media (max-width: 480px) {
    .mobile-header {
        height: 56px;
        padding: 0 12px;
    }
    
    .mobile-header-title {
        font-size: 17px;
    }
    
    .mobile-header-title span::after {
        height: 1px;
        bottom: -3px;
    }
    
    .menu-toggle {
        width: 32px;
        height: 20px;
    }
    
    .hamburger-line {
        height: 3px;
        min-height: 3px;
        background-color: #333 !important;
        margin-top: 5px;
    }
    
    .hamburger-line:first-child {
        margin-top: 0;
    }
    
    .sidebar {
        width: 260px;
        padding: 20px 12px;
        box-sizing: border-box;
    }
    
    .sidebar-header {
        padding-left: 0;
        padding-right: 0;
        margin-left: 0;
        margin-right: 0;
    }
    
    .nav-menu {
        padding-left: 0;
        margin-left: 0;
    }
    
    .nav-menu li {
        width: 100%;
    }
    
    .nav-menu a {
        width: 100%;
        padding: 10px 12px;
        box-sizing: border-box;
    }
    
    .main-content {
        padding: 12px;
        padding-top: 72px;
    }
    
    .footer-nav {
        margin-top: 0;
    }
    
    .footer-nav-menu a {
        padding: 16px 14px;
        font-size: 13px;
    }
    
    .footer-nav-arrow {
        width: 16px;
        height: 16px;
    }
    
    .footer-copyright {
        padding: 12px;
        font-size: 11px;
    }
    
    .page-title {
        font-size: 19px;
    }
    
    .youtube-link-button {
        padding: 8px 14px;
        font-size: 13px;
        margin-bottom: 12px;
    }
    
    .youtube-icon {
        width: 16px;
        height: 16px;
    }
    
    .portfolio-content {
        padding: 12px;
    }
    
    .portfolio-title {
        font-size: 16px;
    }
    
    .portfolio-description {
        font-size: 14px;
    }
    
    .modal-content {
        width: 100%;
        margin: 0;
        border-radius: 0;
        max-height: 100vh;
        height: 100vh;
        justify-content: center;
        background-color: #000;
    }
    
    .modal-image {
        max-height: 70vh;
        margin: auto;
        background-color: #000;
    }
    
    .modal-body {
        padding: 12px;
        background-color: #fff;
    }
    
    .modal-title {
        font-size: 17px;
    }
    
    .modal-description {
        font-size: 14px;
    }
    
    .modal-nav {
        width: 36px;
        height: 36px;
    }
    
    .modal-nav svg {
        width: 18px;
        height: 18px;
    }