styles

1. Why style scoped and what style scoped does?
2. Do I need style scoped for the date-range-picker? the advantages and disadvantages of it?

box-sizing

1. use box-sizing：border-box; for input box

without box-sizing: border-box; because the the icon is inside the input box with padding-left, so the input box is pushed to the right.

[Solved] add box-sizing: border-box for input box

day.off

1. Items that do not belong to the current month（ 不属于当前月份的 item）

td,
th {
  &.off,
  &.off.in-range,
  &.off.start-date,
  &.off.end-date {
    background-color: #fff;
    border-color: transparent;
    color: #999;
  }
}

without .off style: