/* ===== CSS Variables ===== */
:root {
    --primary-color: #1E8E75;
    --secondary-color: #1D0266;
    --background-color: #ffffff;
    --text-color: #333333;
    --light-gray: #f8f9fa;
    --border-color: #e0e0e0;
}

/* ===== Base Styles ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Archivo Narrow', sans-serif;
    font-weight: 400;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
}

p {
    margin-bottom: 0;
}

ul,
ol {
    padding-left: 0 !important;
}

/* ===== Header Styles ===== */
.main-header {
    /* position: fixed を削除し、position: relative を追加 */
    position: relative;
    /* z-index を指定して、他の要素より手前に表示されるようにする */
    z-index: 1000;
    background-color: var(--primary-color);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.main-header .navbar {
    padding: 0.5rem 0;
}

.navbar-brand .logo-text {
    font-size: 1.8rem;
    font-weight: 700;
    color: white;
    text-decoration: none;
}

.desktop-nav .navbar-nav {
    margin-left: auto;
}

.desktop-nav .nav-link {
    color: white !important;
    font-weight: 500;
    padding: 0.5rem 1rem;
    transition: all 0.3s ease;
}

.desktop-nav .nav-link:hover {
    color: #e0e0e0 !important;
}

.dropdown-menu {
    background-color: white;
    border: none;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    border-radius: 0;
    margin-top: 0.5rem;
}

.dropdown-item {
    color: var(--text-color);
    padding: 0.5rem 1rem;
    transition: all 0.3s ease;
}

.dropdown-item:hover {
    background-color: var(--light-gray);
    color: var(--primary-color);
}

/* ===== Mobile Menu Styles (MODIFIED) ===== */
.mobile-menu-toggle {
    cursor: pointer;
}

.hamburger-menu {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.1);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 4px;
    transition: all 0.3s ease;
}

.hamburger-menu:hover {
    background-color: rgba(255, 255, 255, 0.2);
}

.hamburger-menu span {
    width: 20px;
    height: 2px;
    background-color: white;
    transition: all 0.3s ease;
}

.hamburger-menu.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger-menu.active span:nth-child(2) {
    opacity: 0;
}

.hamburger-menu.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
}

.mobile-menu-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background-color: rgba(30, 142, 117, 0.95);
    z-index: 999;
    display: none;
    align-items: center;
    justify-content: center;
    overflow-y: auto;
    padding: 60px 0;
}

.mobile-menu-overlay.active {
    display: flex;
}

.mobile-menu-content {
    width: 90%;
}

.mobile-nav {
    list-style: none;
    text-align: left;
    padding: 0;
}

.mobile-nav li {
    margin: 0.5rem 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.mobile-nav li:last-child {
    border-bottom: none;
}

.mobile-nav a {
    color: white;
    text-decoration: none;
    font-size: 1.2rem;
    font-weight: 500;
    transition: all 0.3s ease;
    display: block;
    padding: 0.75rem 0;
}

.mobile-nav a:hover {
    color: #e0e0e0;
}

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

.mobile-nav .submenu-toggle .fa-chevron-down {
    transition: transform 0.3s ease;
}

.mobile-nav .submenu-toggle[aria-expanded="true"] .fa-chevron-down {
    transform: rotate(180deg);
}

.mobile-submenu {
    list-style: none;
    padding-left: 1.5rem;
    border-radius: 5px;
    margin-top: 0.5rem;
}

.mobile-submenu li {
    border-bottom: none;
    margin: 0;
}

.mobile-submenu li a {
    font-size: 1rem;
    padding: 0.5rem 0;
}

/* ===== Hero Section Styles ===== */
.hero-section {
    position: relative;
    height: 500px;
    overflow: hidden;
}

.hero-slider {
    height: 100%;
}

.hero-slider .slide {
    height: 500px;
    position: relative;
}

.hero-slider .slide img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-content {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    z-index: 10;
}

.hero-logo {
    text-align: center;
    color: white;
}

.main-title {
    font-size: 5.7rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
    line-height: 0.7;
}

.main-title .year {
    color: var(--primary-color);
}

.subtitle {
    font-size: 1.5rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
}

.event-date {
    background-color: var(--primary-color);
    color: white;
    /* border-radius: 5px; */
    font-weight: 600;
    margin-bottom: 0.5rem;
    display: inline-block;
    width: 100%;
    text-align: center;
    font-size: 1.5rem;
}

.event-location {
    font-size: 1.2rem;
    font-weight: 500;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
}

/* ===== Main Content Styles ===== */
.main-content {
    padding: 4rem 0 0;
    margin-top: 0;
}

.section-title {
    color: var(--primary-color);
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 2rem;
    border-left: 4px solid var(--primary-color);
    padding-left: 1rem;
}

/* ===== Important Dates Styles ===== */
.dates-list {}

.date-item {
    display: flex;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.date-item:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.date-badge {
    background-color: var(--primary-color);
    color: white;
    padding: 0.3rem 1rem;
    font-weight: 600;
    min-width: 120px;
    text-align: center;
    margin-right: 1rem;
}

.date-description {
    font-weight: 500;
    color: var(--text-color);
}

/* ===== News Section Styles ===== */
.news-item {
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    overflow-y: scroll;
    height: 200px;
}

.news-item-box {
    border-bottom: 1px solid var(--border-color);
}

.news-date {
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 0.5rem;
}

.news-badge {
    background-color: #dc3545;
    color: white;
    padding: 0.2rem 0.5rem;
    font-size: 0.7rem;
    font-weight: 600;
    margin-left: 0.5rem;
}

.news-title {
    font-weight: 600;
    color: var(--text-color);
    margin-left: 0.5em;
}

/* ===== Welcome Section Styles ===== */
.welcome-content {
    line-height: 1.8;
}

.welcome-content p {
    margin-bottom: 1.5rem;
    text-align: justify;
}

.welcome-content p:last-child {
    margin-bottom: 0;
}

/* ===== Sidebar Styles ===== */
.sidebar {
    padding-left: 2rem;
}

.sidebar-widget {}

.call-papers-btn {
    background-color: #0C7A9E;
    border-color: #0C7A9E;
    font-weight: 600;
    padding: 1rem;
    font-size: 1.8rem;
    line-height: 1.2;
    box-shadow: 2px 2px 8px gray;
}

.call-papers-btn:hover {
    background-color: #138496;
    border-color: #117a8b;
}

.abstract-btn {
    background-color: #C12427;
    border-color: #C12427;
    font-weight: 600;
    padding: 1rem;
    font-size: 1.8rem;
    line-height: 1.2;
    box-shadow: 2px 2px 8px gray;
}

.abstract-btn:hover {
    background-color: #c82333;
    border-color: #bd2130;
}

.contact-widget {
    background-color: white;
}

.widget-title {
    color: var(--primary-color);
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--primary-color);
}

.contact-info p {
    margin-bottom: 0;
    font-size: 1.2rem;
}

.contact-email {
    color: var(--primary-color);
    text-decoration: none;
}

.contact-email:hover {
    text-decoration: underline;
}

/* ===== Sponsors Section Styles ===== */
.sponsors-section {}

.sponsor-item {
    background-color: white;
    padding: 1rem;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.sponsor-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.15);
}

.sponsor-item img {
    border-radius: 5px;
}

/* ===== Footer Styles (MODIFIED) ===== */
.main-footer {
    background-color: var(--background-color);
    color: var(--text-color);
    padding: 2.2rem 0 0;
    border-top: 1px solid var(--primary-color);
}

.footer-logo {
    border-bottom: 1px solid;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--primary-color);
}

.footer-title {
    color: var(--secondary-color);
    font-size: 5.5rem;
    font-weight: 700;
    line-height: 0.7;
}

.footer-subtitle {
    color: var(--text-color);
    font-weight: 600;
    font-size: 1.2rem;
}

.footer-title .year {
    color: var(--primary-color);
}

.footer-date span {
    color: var(--primary-color);
}

.footer-menu {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    padding: 0;
    margin: 0;
}


.footer-menu li {
    padding: 0 1rem;
    border-right: 1px solid #000;
}

.footer-menu li:last-child {
    border-right: none;
}

.footer-menu a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
}

.footer-menu ul {
    text-align: center;
}

.footer-menu ul li {
    list-style: none;
    font-size: 0.8em;
    border-right: none;
}

.footer-menu ul li a {
    color: #ccc;
}




.footer-menu a:hover {
    color: var(--primary-color);
}

.footer-copyright {
    color: #fff;
    font-size: 0.9rem;
    background-color: var(--secondary-color);
    text-align: center;
    padding: 0.8rem 0;
}

/* ===== Back to Top Button ===== */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background-color: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: none;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    z-index: 1000;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.back-to-top:hover {
    background-color: var(--secondary-color);
    transform: translateY(-3px);
}

.back-to-top.show {
    display: flex;
}

/* ===== Responsive Styles ===== */
@media (max-width: 991.98px) {
    .sidebar {
        padding-left: 0;
        margin-top: 3rem;
    }

    .hero-logo {
        text-align: center;
    }

    .main-title {
        font-size: 5rem;
    }

    .footer-menu {
        flex-direction: column;
        gap: 0.5rem;
    }

    .footer-menu li {
        border-right: none;
        padding: 0.25rem 0;
        border-bottom: 1px solid var(--border-color);
    }

    .footer-menu li:last-child {
        border-bottom: none;
    }
}

@media (max-width: 767.98px) {
    .main-title {
        font-size: 2.5rem;
    }

    .subtitle {
        font-size: 1.2rem;
    }

    .hero-logo {
        padding: 1rem;
    }

    .main-content {
        padding: 2rem 0;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .date-item {
        flex-direction: column;
        align-items: flex-start;
        text-align: left;
    }

    .date-badge {
        margin-right: 0;
        margin-bottom: 0.5rem;
        min-width: auto;
    }

    .back-to-top {
        bottom: 1rem;
        right: 1rem;
        width: 45px;
        height: 45px;
    }
}

@media (max-width: 575.98px) {
    .main-title {
        font-size: 4rem;
    }

    .hero-content {
        padding: 1rem;
    }

    .container {
        padding-left: 1rem;
        padding-right: 1rem;
    }
}

/* ===== Slick Carousel Custom Styles ===== */
.slick-dots {
    display: none !important;
}

.slick-arrow {
    display: none !important;
}

.hero-slider .slick-slide {
    outline: none;
}

/* ===== Lightbox2 Custom Styles ===== */
.lb-data .lb-caption {
    font-family: 'Archivo Narrow', sans-serif;
}

/* ===== Animation Classes ===== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== Utility Classes ===== */
.text-primary-custom {
    color: var(--primary-color) !important;
}

.bg-primary-custom {
    background-color: var(--primary-color) !important;
}

.text-secondary-custom {
    color: var(--secondary-color) !important;
}

.bg-secondary-custom {
    background-color: var(--secondary-color) !important;
}

/* モバイルメニュー表示中のbodyスクロール禁止 */
.menu-open {
    overflow: hidden;
}