css - 横スクロール時のマットテーブルの背景色

Question

mat-tableangular 6アプリケーションで使用すると、水平スクロールの背景色を適切にmat-header-row設定できません。mat-rowCSS プロパティは、画面の表示部分にのみ適用されます。右にスクロールすると、色は割り当てられません。

テーブルには約 30 列あるので、必ず水平スクロールが必要です。

私のCSSは次のとおりです。

.mat-toolbar {
    font-size: 17px;
    font-family: inherit;
    background-color: indigo;
    max-height: 12vh;
}

.mat-elevation-z8 {
    padding: 0px;
}

.mat-table {
    overflow: auto;
    max-height: 68vh;
    min-width: 100%;
}

.mat-header-row {
    position: sticky;
    top: -.5px;
    z-index: 100;
    background-color: gainsboro;
    font-size: 12px;
    min-height: 8vh;
    color: #f5f5f5;
    padding-top: 3px;
}

.mat-row:nth-child(even) {
    background-color: floralwhite;
}

.mat-row:nth-child(odd) {
    background-color: gainsboro;
}

.mat-row {
    min-height: 8vh;
}

.no-results {
    display: flex;
    justify-content: center;
    padding: 12px;
    font-size: 12px;
    font-style: italic;
    font-family: inherit;
}

.mat-cell {
    font-family: inherit;
    font-size: 12px;
}

.mat-header-cell {
    font-size: 12px;
    font-weight: bolder;
}

.mat-cell:nth-child(1),
.mat-header-cell:nth-child(1) {
    flex: 0 0 6%;
}

.mat-cell:nth-child(2),
.mat-header-cell:nth-child(2) {
    flex: 0 0 9%;
}

.mat-cell:nth-child(3),
.mat-header-cell:nth-child(3) {
    flex: 0 0 14%;
}

.mat-cell:nth-child(4),
.mat-header-cell:nth-child(4) {
    flex: 0 0 10%;
}

.mat-cell:nth-child(5),
.mat-header-cell:nth-child(5) {
    flex: 0 0 10%;
}

.mat-cell:nth-child(6),
.mat-header-cell:nth-child(6) {
    flex: 0 0 8%;
}

.mat-cell:nth-child(7),
.mat-header-cell:nth-child(7) {
    flex: 0 0 9%;
}

.mat-cell:nth-child(8),
.mat-header-cell:nth-child(8) {
    flex: 0 0 8%;
}

.mat-cell:nth-child(9),
.mat-header-cell:nth-child(9) {
    flex: 0 0 8%;
}

.mat-cell:nth-child(10),
.mat-header-cell:nth-child(10) {
    flex: 0 0 9%;
}

.mat-cell:nth-child(11),
.mat-header-cell:nth-child(11) {
    flex: 0 0 8%;
}

.mat-cell:nth-child(12),
.mat-header-cell:nth-child(12) {
    flex: 0 0 11%;
}

.mat-cell:nth-child(13),
.mat-header-cell:nth-child(13) {
    flex: 0 0 7%;
}

.mat-cell:nth-child(14),
.mat-header-cell:nth-child(14) {
    flex: 0 0 11%;
}

.mat-cell:nth-child(15),
.mat-header-cell:nth-child(15) {
    flex: 0 0 7%;
}

.mat-cell:nth-child(16),
.mat-header-cell:nth-child(16) {
    flex: 0 0 8%;
}

.mat-column-name {
    border-right: 1px solid grey;
    align-self: stretch;
    text-align: center;
}

.mat-column-position {
    border-right: 1px solid grey;
    align-self: stretch;
    text-align: center;
}

.mat-column-weight {
    border-right: 1px solid grey;
    align-self: stretch;
    text-align: center;
}

.mat-column-symbol {
    text-align: center;
    align-self: stretch;
}

.mat-column-weight {
    align-self: stretch;
}

オーバーフロー プロパティを mat-h​​eader-row と mat-row に個別に設定しようとしました。背景色を解決しますが、ヘッダー行とデータ行は同期せずに別々にスクロールできます。

HTML ファイルは次のとおりです。

<div [@routerTransition] class="col-md-12 mat-elevation-z8" class="white-space-pre-line">
    <mat-toolbar color="primary">
        Project Times Overview Report
        <span class="spacer"></span>
        <mat-select *ngxPermissionsOnly="['attendance-all-leave-balance-read']" name="year" [(ngModel)]="selectedYear"
            class="form-control" type="text" placeholder="Year" required>
            <mat-option *ngFor="let year of yearName" [value]="year">{{year}}</mat-option>
        </mat-select> &nbsp;
        <button class="btn btn-sm btn-primary" *ngxPermissionsOnly="['attendance-all-leave-balance-read']" [disabled]="selectedYear==''"
            (click)="loadData()">View Report</button>
    </mat-toolbar>

    <div class="form">
        <mat-form-field floatPlaceholder="never" color="primary">
            <input matInput #filter placeholder="Filter">
        </mat-form-field>
    </div>

    <mat-table #table [dataSource]="dataSource" matSort class="mat-cell">
        <ng-container matColumnDef="sno">
            <mat-header-cell *matHeaderCellDef>S.No.</mat-header-cell>
            <mat-cell *matCellDef="let timesReport; let i = index;">{{i+1}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="timesCode">
            <mat-header-cell *matHeaderCellDef>Times Code</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.timesCode}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="projectName">
            <mat-header-cell *matHeaderCellDef>Project</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.projectName}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="team">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Team</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{getTeamDesc(timesReport)}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="department">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Department</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{getDeptDesc(timesReport)}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="allocatedWorkload">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Allocated PD</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.allocatedWorkload}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="activity">
            <mat-header-cell *matHeaderCellDef>Activity</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.activity}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="actualWorkload">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Actual Received PD</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.actualWorkload}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="createdBy">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Created By</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.createdBy}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="creationDate">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Creation Date</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.creationDate}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="approvedBy">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Approved By</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.approvedBy}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="approvalDate">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Approval Date</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.approvalDate}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="claimed">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Claimed PD</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.claimed}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="unclaimed">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Unclaimed PD</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.unclaimed}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="gapActualAllocated">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Gap (Actual vs Allocated)</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.gapActualAllocated}}</mat-cell>
        </ng-container>

        <ng-container matColumnDef="lossPD">
            <mat-header-cell *matHeaderCellDef mat-sort-header>Loss PD</mat-header-cell>
            <mat-cell *matCellDef="let timesReport">{{timesReport.lossPD}}</mat-cell>
        </ng-container>

        <mat-header-row *matHeaderRowDef="dispProjectTimesReportColumns"></mat-header-row>
        <mat-row *matRowDef="let row; columns: dispProjectTimesReportColumns;"></mat-row>
    </mat-table>

    <div class="no-results" [style.display]="dataSource.renderedData.length == 0 ? '' : 'none'">
        No results found
    </div>

    <mat-paginator #paginator [length]="dataSource.filteredData.length" [pageIndex]="0" [pageSize]="100"
        [pageSizeOptions]="[25, 50, 100, 200]">
    </mat-paginator>

</div>

Deepuの回答に従うと、背景は次のように表示されます。