.announcement-layout {
    display: flex;
    gap: 2rem;
    padding: 2rem;
    align-items: flex-start;
    font-family: 'Segoe UI', sans-serif;
    background-color: #fafafa;
}

.sidebar {
    width: 25%;
    max-width: 280px;
    border-right: 1px solid #ddd;
    padding-right: 1rem;
    overflow-y: auto;
    max-height: 90vh;
}

.content {
    flex: 1;
    padding: 1rem;
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}

.year-group {
    margin-bottom: 1.5rem;
}

.year-header {
    font-weight: bold;
    background: none;
    border: none;
    padding: 0.5rem 0;
    width: 100%;
    text-align: left;
    font-size: 1rem;
    cursor: pointer;
    color: #444;
    transition: color 0.2s;
}

.year-header:hover {
    color: #b0d8fa;
}

.year-list.hidden {
    display: none;
}

.announcement-link {
    margin: 0.25rem 0 0.25rem 1rem;
    padding: 0.4rem 0.5rem;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.2s, color 0.2s;
    color: #005999;
}

.announcement-link:hover {
    background-color: #eef6ff;
    color: #003366;
}

.announcement-link.active {
    background-color: #d9ecff;
    font-weight: 600;
    color: #003366;
}

.announcement-title {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.announcement-date {
    font-size: 0.9rem;
    color: #888;
    margin-bottom: 1rem;
    display: block;
}

.announcement-text {
    font-size: 1rem;
    line-height: 1.6;
    margin-bottom: 1rem;
    color: #333;
}

.announcement-image {
    max-width: 100%;
    height: auto;
    border-radius: 6px;
    margin-top: 1rem;
}