.archive-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
    text-align: left;
    font-family: 'Georgia', serif;
}

.archive-folder {
    border: 1px solid var(--sep-color);
    transition: border-color 0.3s ease;
}

.archive-folder:hover {
    border-color: var(--accent-color);
}

.folder-header {
    padding: 15px 20px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    user-select: none;
    transition: background 0.3s ease;
}

.folder-header:hover {
    background: var(--panel-bg);
}

.folder-year {
    font-size: 1rem;
    color: var(--accent-color);
    font-family: 'Times New Roman', serif;
    letter-spacing: 0.1em;
}

.folder-icon {
    font-family: 'Courier New', monospace;
    font-size: 0.8rem;
    color: var(--latin-color);
    transition: transform 0.3s ease;
}

/* 折叠内容样式 */
.folder-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    background: rgba(255, 255, 255, 0.01);
    border-top: 0px solid var(--sep-color);
}

.archive-folder.open .folder-content {
    max-height: 500px; /* 足够容纳子项的高度 */
    border-top-width: 1px;
}

.archive-folder.open .folder-icon {
    transform: rotate(45deg); /* + 变成 x 或 简单的旋转 */
}

.sub-item {
    padding: 10px 20px;
    font-size: 0.8rem;
    color: var(--latin-color);
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: 'Courier New', monospace;
    border-left: 1px solid transparent;
    margin: 4px 0;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.sub-item:hover {
    color: var(--accent-color);
    background: var(--panel-bg);
    border-left-color: var(--accent-color);
    padding-left: 25px;
}