.umb-expansion-panel {
    background: @white;
    border-radius: 3px;
    margin-bottom: 20px;
    box-shadow: 0 1px 1px 0 rgba(0, 0, 0, 0.16);
}

.umb-expansion-panel__header {
    padding: 10px 20px;
    font-weight: bold;
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: @black;
    width: 100%;

    &:hover .umb-expansion-panel__expand,
    &:focus .umb-expansion-panel__expand {
        color: @gray-6;
    }
}

.umb-expansion-panel__expand {
    color: @gray-8;
}

.umb-expansion-panel__content {
    padding: 20px;
    border-top: 1px solid @gray-9;
}

.umb-expansion-panel {
    background: @white;
    border-radius: 3px;
    margin-bottom: 20px;
    box-shadow: 0 1px 1px 0 rgba(0, 0, 0, 0.16);
}

.umb-expansion-panel__header {
    box-sizing: border-box;
    padding: 10px 20px;
    font-weight: bold;
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: @black;
    width: 100%;

    &:hover .umb-expansion-panel__expand,
    &:focus .umb-expansion-panel__expand {
        color: @gray-6;
    }
}

.umb-expansion-panel__expand {
    color: @gray-8;
}

.umb-expansion-panel__content {
    padding: 20px;
    border-top: 1px solid @gray-9;
}

Fix expansion panel header causing horizontal overflow
Fix expansion panel header causing horizontal overflow
