:root {
    --primary-color: #1e4a7b;
    --secondary-color: #7cb342;
    --accent-color: #ff6b35;
    --text-dark: #2d3748;
    --text-light: #718096;
    --bg-light: #f7fafc;
    --bg-white: #ffffff;
    --border-color: #e2e8f0;
    --shadow: 0 2px 8px rgba(0,0,0,0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background: var(--bg-white);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.site-header {
    background: var(--bg-white);
}

.header-top {
    padding: 15px 0;
    background: linear-gradient(135deg, var(--header-gradient-start, #1e4a7b) 0%, var(--header-gradient-end, #7cb342) 100%);
}

.header-logo {
    max-height: 60px;
    width: auto;
}

.main-navigation {
    /* background: var(--bg-white); */
    /* background: var(--secondary-color); */
    background: var(--border-color);
    border-top: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow);
}

.nav-menu {
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
}

.nav-item {
    margin: 0 30px;
}

.nav-link {
    display: block;
    padding: 20px 0;
    color: var(--text-dark);
    text-decoration: none;
    font-weight: 500;
    font-size: 16px;
    transition: color 0.3s, border-bottom 0.3s;
    /* border-bottom: 3px solid transparent; */
    border-bottom: 5px solid transparent;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
    /* border-bottom-color: var(--secondary-color); */
    border-bottom-color: var(--accent-color);
}

.hero-section {
    background: linear-gradient(135deg, 
                rgba(var(--hero-gradient-start-rgb, 30, 74, 123), 0.9) 0%, 
                rgba(var(--hero-gradient-end-rgb, 124, 179, 66), 0.9) 100%),
                url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1200 400"><rect fill="%23f0f0f0"/><path d="M0,200 Q300,100 600,200 T1200,200" stroke="%23ddd" stroke-width="2" fill="none"/></svg>');
    background-size: cover;
    color: white;
    padding: 60px 0;
    text-align: center;
}

.hero-title {
    font-size: 36px;
    margin-bottom: 15px;
    font-weight: 700;
}

.hero-subtitle {
    font-size: 24px;
    margin-bottom: 10px;
    font-weight: 400;
}

.hero-date {
    font-size: 20px;
    opacity: 0.95;
}

.overview-section,
.program-section,
.participants-section {
    padding: 60px 0;
}

.lead {
    font-size: 18px;
    /* color: var(--text-light); */
    margin-bottom: 10px;
    line-height: 1.8;
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.info-card {
    background: var(--bg-white);
    padding: 30px;
    border-radius: 8px;
    box-shadow: var(--shadow);
    border-left: 4px solid var(--secondary-color);
}

.info-card h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 20px;
}

.info-card ul {
    list-style: none;
    padding-left: 0;
}

.info-card li {
    padding: 5px 0;
    border-bottom: 1px solid var(--border-color);
}

.info-card li:last-child {
    border-bottom: none;
}

.themes-section {
    margin-top: 60px;
}

.themes-section h2 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 28px;
}

.topic-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.topic-card {
    background: var(--bg-light);
    padding: 30px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.topic-card h4 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 18px;
}

.topic-card ul {
    list-style: none;
    padding-left: 0;
}

.topic-card li {
    padding: 8px 0;
    padding-left: 20px;
    position: relative;
}

.topic-card li:before {
    content: "▸";
    position: absolute;
    left: 0;
    color: var(--secondary-color);
}

.page-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 10px 0;
    text-align: center;
    /* margin-bottom: 40px; */
}

.page-header h1 {
    font-size: 36px;
    margin-bottom: 10px;
}

.schedule-overview h2,
.program-highlights h2 {
    color: var(--primary-color);
    margin-bottom: 30px;
    font-size: 28px;
}

.day-schedule {
    background: var(--bg-white);
    border-radius: 8px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
    overflow: hidden;
}

.day-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 20px 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.day-header h3 {
    font-size: 22px;
}

.day-theme {
    font-size: 14px;
    background: rgba(255,255,255,0.2);
    padding: 5px 15px;
    border-radius: 20px;
}

.schedule-items {
    padding: 20px 30px;
}

.schedule-item {
    display: flex;
    padding: 15px 0;
    border-bottom: 1px solid var(--border-color);
}

.schedule-item:last-child {
    border-bottom: none;
}

.schedule-item .time {
    flex: 0 0 140px;
    font-weight: 600;
    color: var(--primary-color);
}

.schedule-item .event {
    flex: 1;
    color: var(--text-dark);
}

.schedule-item .venue {
    flex: 0 0 250px;
    color: var(--text-light);
    font-size: 14px;
    text-align: right;
    padding-left: 15px;
}

.highlight-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.highlight-card {
    background: var(--bg-white);
    padding: 30px;
    border-radius: 8px;
    box-shadow: var(--shadow);
    border-top: 4px solid var(--accent-color);
}

.highlight-card h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 20px;
}

.filter-controls {
    display: flex;
    gap: 20px;
    margin-bottom: 40px;
    flex-wrap: wrap;
    align-items: center;
    background: var(--bg-light);
    padding: 20px;
    border-radius: 8px;
}

.filter-group {
    display: flex;
    flex-direction: column;
    gap: 5px;
}

.filter-group label {
    font-size: 14px;
    color: var(--text-light);
    font-weight: 600;
}

.filter-select,
.search-input {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 14px;
    background: var(--bg-white);
}

.search-input {
    width: 200px;
}

.participants-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 30px;
}

.participant-card {
    background: var(--bg-white);
    border-radius: 8px;
    box-shadow: var(--shadow);
    padding: 25px;
    transition: transform 0.3s, box-shadow 0.3s;
    border-top: 3px solid var(--secondary-color);
}

.participant-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.participant-card[style*="display: none"] {
    display: none !important;
}

.participant-avatar {
    text-align: center;
    margin-bottom: 20px;
}

.participant-avatar img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    border: 3px solid var(--border-color);
}

.participant-info {
    text-align: center;
}

.participant-name {
    color: var(--primary-color);
    font-size: 20px;
    margin-bottom: 5px;
}

.participant-role {
    color: var(--accent-color);
    font-weight: 600;
    font-size: 14px;
    margin-bottom: 10px;
}

.participant-field {
    color: var(--text-light);
    font-size: 14px;
    margin-bottom: 5px;
    font-style: italic;
}

.participant-title,
.participant-affiliation,
.participant-location {
    font-size: 14px;
    color: var(--text-dark);
    margin-bottom: 3px;
}

.participant-website {
    display: inline-block;
    margin-top: 10px;
    color: var(--primary-color);
    text-decoration: none;
    font-size: 14px;
    font-weight: 600;
}

.participant-website:hover {
    color: var(--secondary-color);
}

.participant-bio {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid var(--border-color);
    position: relative;
}

.bio-text {
    color: var(--text-light);
    font-size: 13px;
    line-height: 1.35;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    text-overflow: ellipsis;
    transition: all 0.3s ease;
    text-align: start;
}

.participant-bio.expanded .bio-text {
    -webkit-line-clamp: unset;
    display: block;
}

.bio-toggle {
    margin-top: 10px;
    background: none;
    border: none;
    color: var(--secondary-color);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    padding: 5px 0;
    transition: color 0.3s;
}

.bio-toggle:hover {
    color: var(--primary-color);
    text-decoration: underline;
}

/* Organizers Logo Bar */
.organizers-bar {
    background: linear-gradient(135deg, #f5f5f5 0%, #ffffff 100%);
    border-top: 1px solid #e0e0e0;
    border-bottom: 1px solid #e0e0e0;
    padding: 25px 20px;
    margin-top: 60px;
}

.organizers-logos {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 30px;
    flex-wrap: wrap;
    max-width: 1000px;
    margin: 0 auto;
}

.organizer-logo {
    flex: 1;
    min-width: 120px;
    max-width: 180px;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: transform 0.3s ease, opacity 0.3s ease;
    opacity: 0.8;
    text-decoration: none;
}

.organizer-logo:hover {
    transform: translateY(-3px);
    opacity: 1;
}

.organizer-logo img {
    max-width: 100%;
    height: auto;
    max-height: 60px;
    object-fit: contain;
    transition: transform 0.3s ease, opacity 0.3s ease;
}

.organizer-logo:hover img {
    transform: scale(1.05);
}

.logo-img {
    display: block;
}

/* Option 2: Card Style */
.organizers-section {
    /* background: #fafafa; */
    padding: 35px 20px;
    /* border-bottom: 3px solid #1e4a7b; */
}

.organizers-label {
    text-align: center;
    font-size: 0.9rem;
    font-weight: 600;
    color: #666;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 25px;
}

.organizers-cards {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
    max-width: 1000px;
    margin: 0 auto;
}

.organizer-card {
    background: white;
    padding: 20px 25px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
    text-decoration: none;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 180px;
    height: 90px;
}

.organizer-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 16px rgba(30, 74, 123, 0.2);
}

.organizer-card img {
    max-height: 50px;
    max-width: 160px;
    width: auto;
    height: auto;
    object-fit: contain;
}

.site-footer {
    /* background: var(--text-dark); */
    background: var(--primary-color);
    color: white;
    padding: 60px 0 20px;
    margin-top: 80px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h3 {
    color: var(--secondary-color);
    margin-bottom: 15px;
    font-size: 18px;
}

.footer-list,
.footer-links {
    list-style: none;
}

.footer-list li,
.footer-links li {
    padding: 5px 0;
}

.footer-list a {
    color: var(--footer-link-color, #7cb342);  /* テーマに応じて変更可能 */
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-list a:hover {
    color: var(--footer-link-hover, #9ccc65);  /* テーマに応じて変更可能 */
    text-decoration: underline;
}

.footer-links a {
    color: rgba(255,255,255,0.8);
    text-decoration: none;
}

.footer-links a:hover {
    color: var(--secondary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255,255,255,0.1);
    color: rgba(255,255,255,0.6);
}

@media (max-width: 768px) {
    .nav-menu {
        /* flex-direction: column; */
    }

    .nav-item {
        margin: 0;
        width: 100%;
        text-align: center;
    }

    .hero-title {
        font-size: 28px;
    }

    .hero-subtitle {
        font-size: 20px;
    }

    .topic-cards {
        grid-template-columns: 1fr;
    }

    .day-header {
        flex-direction: column;
        gap: 10px;
    }

    .schedule-item {
        flex-direction: column;
        gap: 5px;
    }

    .filter-controls {
        flex-direction: column;
        align-items: stretch;
    }

    .search-input {
        width: 100%;
    }

    .schedule-item .time {
       flex: unset;
    }

    .schedule-item .venue {
        flex: unset;
        text-align: left;
        padding-left: 0;
        font-size: 13px;
        margin-top: 5px;
    }

    .organizers-logos {
        gap: 15px;
    }

    .organizer-logo {
        min-width: 100px;
    }

    .organizers-cards {
        gap: 15px;
    }

    .organizer-card {
        min-width: 100px;
    }

}