/* === 1. Reset & Basic Settings === */
html {
    scroll-behavior: smooth;
}
body {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    font-family: 'Noto Sans JP', Arial, sans-serif;
    color: #333;
    padding-top: 65px; 
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    box-sizing: border-box;
}
main {
    flex-grow: 1;
}
a {
    color: #007bff;
    text-decoration: none;
    overflow-wrap: break-word;
}
a:hover {
    text-decoration: underline;
}
img {
    max-width: 100%;
    height: auto;
}

/* === 2. Common Layout === */
/* --- Navigation Bar --- */
.navbar {
    position: fixed;
    top: 0; left: 0; width: 100%;
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: auto;
    padding: 0 20px;
    height: 65px;
}
.logo { font-size: 22px; font-weight: bold; }
.logo a { color: #333; text-decoration: none; }
.nav-links { list-style: none; display: flex; margin: 0; padding: 0; }
.nav-links a { color: #333; padding: 8px 15px; margin: 0 5px; border-radius: 4px; transition: background-color 0.3s; text-decoration: none; }
.nav-links a:hover { background-color: #e9ecef; text-decoration: none; }
.menu-toggle { display: none; background: none; border: none; font-size: 28px; cursor: pointer; }

/* --- Main Content Wrapper --- */
.wrap {
    max-width: 1200px;
    margin: 40px auto;
    background-color: #ffffff;
    box-shadow: 0 0 15px rgba(0,0,0,0.07);
}

/* --- Section --- */
.session {
    padding: 50px 40px;
    border-bottom: 1px solid #e9ecef;
}
.session:last-child { border-bottom: none; }
.sub-section-heading {
    font-size: 26px;
    font-weight: bold;
    color: #333;
    margin-top: 50px;
    margin-bottom: 25px;
    border-bottom: 2px solid #eee;
    padding-bottom: 8px;
}

/* --- Footer --- */
footer {
    background-color: #343a40;
    color: #adb5bd;
    padding: 30px 0;
    font-size: 14px;
}
.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    text-align: right;
}
footer a { color: #ced4da; margin-right: 15px; }
footer a:hover { color: white; }

/* === 3. Archive Notice === */
.archive-notice {
    background-color: #fff3cd;
    color: #856404;
    border-bottom: 1px solid #ffeeba;
    padding: 15px 40px;
    font-size: 16px;
    text-align: left;
}

/* === 4. Page Specific Styles === */
/* --- ページ専用ヘッダー --- */
.page-specific-header {
    background: #2c3e50;
    color: white;
    padding: 60px 20px;
    text-align: center;
}
.page-specific-header-content h1 {
    margin: 0;
    font-size: 36px;
}
.page-specific-header-content p {
    margin: 10px 0 0 0;
    font-size: 18px;
    opacity: 0.9;
}

/* --- 活動内容グリッド --- */
.activity-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
}
.activity-card {
    background: #f8f9fa;
    padding: 25px;
    border-radius: 8px;
}
.activity-card h4 {
    margin-top: 0;
    font-size: 18px;
}
.activity-card p {
    margin-bottom: 0;
    line-height: 1.8;
    color: #555;
}

/* --- タイムライン --- */
.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
}
.timeline::after {
    content: '';
    position: absolute;
    width: 3px;
    background-color: #e9ecef;
    top: 0;
    bottom: 0;
    left: 15px;
    margin-left: -1.5px;
}
.timeline-item {
    padding: 10px 40px;
    position: relative;
    background-color: inherit;
}
.timeline-dot {
    content: '';
    position: absolute;
    width: 15px;
    height: 15px;
    border-radius: 50%;
    background-color: white;
    border: 4px solid #007bff;
    top: 24px;
    left: 15px;
    transform: translateX(-50%);
    z-index: 1;
}
.timeline-content {
    padding: 20px;
    background-color: white;
    border: 1px solid #e9ecef;
    border-radius: 8px;
}
.timeline-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    font-weight: bold;
}
.event-badge {
    padding: 4px 12px;
    border-radius: 15px;
    font-size: 12px;
    color: white;
}
.event-badge.finished { background-color: #6c757d; }

.event-details {
    list-style: none;
    padding: 0;
    margin: 0;
    line-height: 1.8;
    font-size: 15px;
}

/* === 5. Responsive (Mobile) === */
@media (max-width: 768px) {
    body { padding-top: 60px; }
    .nav-container { height: 60px; }
    .nav-links { display: none; flex-direction: column; background: white; position: absolute; top: 60px; right: 0; width: 100%; box-shadow: 0 4px 5px rgba(0,0,0,0.1); }
    .nav-links.active { display: flex; }
    .nav-links li { text-align: center; border-top: 1px solid #f0f0f0; }
    .nav-links a { display: block; padding: 15px; margin: 0; }
    .menu-toggle { display: block; }
    
    .wrap { margin: 20px 0; }
    .session { padding: 40px 20px; }
    .archive-notice { padding: 15px 20px; }

    .activity-grid { grid-template-columns: 1fr; }
    
    .timeline::after { left: 15px; }
    .timeline-item { padding-left: 40px; padding-right: 15px; }
    .timeline-dot { left: 15px; }
}