/* ========== 顶部导航 ========== */
.main-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 64px;
    background: var(--md-sys-color-primary);
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: var(--md-sys-elevation-level1);
    z-index: 1000;
    color: var(--md-sys-color-on-primary);
}
.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 600;
    font-size: 20px;
}
.user-info {
    display: flex;
    align-items: center;
    gap: 16px;
    font-size: 14px;
}

/* 应用主容器 */
.app-container {
    display: flex;
    height: calc(100vh - 64px);
    overflow: hidden;
}

/* PC侧边栏 */
.sidebar {
    width: 280px;
    background: var(--md-sys-color-surface);
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 24px;
    border-right: 1px solid var(--md-sys-color-outline-variant);
    transition: transform var(--md-sys-motion-duration-medium) var(--md-sys-motion-easing-standard);
    flex-shrink: 0;
}
.sidebar-section {
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.sidebar-title {
    font-size: 12px;
    font-weight: 500;
    color: var(--md-sys-color-on-surface-variant);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding-left: 12px;
    margin-bottom: 4px;
}
.sidebar-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    border-radius: var(--md-sys-shape-corner-extra-large);
    cursor: pointer;
    color: var(--md-sys-color-on-surface-variant);
    transition: all var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard);
    position: relative !important;
    padding-right: 40px !important;
}
.sidebar-item span {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    flex: 1;
}
.sidebar-item:hover { background: var(--md-sys-color-surface-variant); }
.sidebar-item.active {
    background: var(--md-sys-color-primary-container) !important;
    color: var(--md-sys-color-on-primary-container) !important;
    font-weight: 600;
    box-shadow: var(--md-sys-elevation-level1);
}
.sidebar-item .material-icons { font-size: 20px; }

/* 侧边栏删除按钮hover显示 */
.sidebar-item .group-delete-btn {
    display: none !important;
    position: absolute !important;
    right: 4px !important;
    top: 50% !important;
    transform: translateY(-50%) !important;
    width: 36px !important;
    height: 36px !important;
    border-radius: 50% !important;
    background: transparent !important;
    border: none !important;
    color: #666 !important;
    cursor: pointer !important;
    z-index: 10 !important;
}
.sidebar-item:hover .group-delete-btn {
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
}

/* 移动端分组切换按钮 */
.mobile-group-toggle { display: none; }
#mobile-current-group {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 130px;
}

/* 主内容区 */
.main-content {
    flex: 1;
    padding: 24px;
    overflow-y: auto;
    position: relative;
    min-width: 0;
    width: 100%;
}
.page-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 24px;
}
.page-title {
    font-size: var(--md-sys-typescale-headline-small-size);
    font-weight: var(--md-sys-typescale-headline-small-weight);
    line-height: var(--md-sys-typescale-headline-small-line-height);
    color: var(--md-sys-color-on-surface);
    transition: opacity var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard);
}
.page-actions { display: flex; gap: 8px; }

.action-bar {
    display: flex;
    gap: 16px;
    margin-bottom: 24px;
    flex-wrap: wrap;
    align-items: center;
}