/* ========== 侧边栏 ========== */
.sidebar {
    width: var(--sidebar-width);
    min-width: var(--sidebar-width);
    height: 100vh;
    background: var(--color-sidebar);
    border-right: 2px solid var(--color-border);
    display: flex;
    flex-direction: column;
    padding: 20px 16px;
    gap: 16px;
    overflow-y: auto;
    z-index: 10;
    flex-shrink: 0;
}

.sidebar-header {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.sidebar-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text);
    text-align: center;
    padding: 8px 0;
    letter-spacing: 2px;
}

.sidebar-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.conversation-list {
    flex: 1;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding: 4px 0;
    min-height: 0;
}

.conversation-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 16px;
    background: var(--color-white);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition);
    border: 2px solid transparent;
    font-size: var(--font-size-md);
    box-shadow: var(--shadow-sm);
    position: relative;
}
.conversation-item:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-md);
    transform: translateX(2px);
}
.conversation-item.active {
    border-color: var(--color-primary);
    background: var(--color-primary-light);
    font-weight: 700;
}
.conversation-info {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.conversation-title {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size: var(--font-size-md);
    font-weight: 600;
}
.conversation-meta {
    font-size: var(--font-size-xs);
    color: var(--color-text-light);
    white-space: nowrap;
}
.conversation-delete {
    flex-shrink: 0;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: none;
    background: transparent;
    cursor: pointer;
    font-size: 20px;
    color: var(--color-text-light);
    transition: all var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 1;
}
.conversation-delete:hover {
    background: #fce4e4;
    color: var(--color-danger);
}

.no-conversations {
    text-align: center;
    padding: 30px 16px;
    color: var(--color-text-light);
    font-size: var(--font-size-md);
    line-height: 1.8;
}
.no-conversations .icon {
    font-size: 48px;
    display: block;
    margin-bottom: 12px;
}