@salesforce/design-system-react/assets/styles/table.css

Salesforce Lightning Design System for React

.slds-table-column-resizer{
    border-left: 1px solid #0176d3;
}

.grip-handle:hover, .grip-handle-active{
    border-left: 1px solid #0176d3;
}

.grip-handle:hover:before, .grip-handle-active:before{
    background-color: #0176d3;
    width: .25rem;
    height: 100%;
    content: " ";
    position: absolute;
    height: 33px;
    right: -1.4px;
}

.grip-handle:active:before{
    background-color: #0176d3;
    width: .25rem;
    height: 100%;
    content: " ";
    position: absolute;
    height: 33px;
    right: -1.4px; 
}

.grip-handle .grip-resizable  {
    background-color: #0176d3;
    width: 1px;
    height: 100vh;
    opacity: 0;
}

.slds-table_fixed-layout .grip-handle {
    position: absolute;
    z-index: 9;
    background-color: #0176d3;
    width: 1px;
    height: 100vh;
    opacity: 0;
    top: -33px;
    z-index: 9;
}

.slds-table_fixed-layout .grip-container {
    position: absolute;
}

.slds-table_header-fixed_container .grip-handle {
    position: absolute;
    top: -33px;
    z-index: 9;
}

.slds-table_header-fixed_container .grip-container {
    position: absolute;
}

.slds-table th:focus .slds-cell-fixed, .slds-table th.slds-has-focus .slds-cell-fixed, .slds-table [role="gridcell"]:focus , .slds-table [role="gridcell"].slds-has-focus{
    box-shadow: #0070d2 0 0 0 1px inset;
}

th > div > .slds-truncate {
    padding-left: 0.5rem;
    padding-right: 0.5rem;
    padding: 0.25rem 0.5rem;
    height: 2rem;
}