ant-design/style/mixins/input.less

.ant-input(){
  position: relative;
  display: inline-block;
  margin: 0 0;
  padding: 4px 10px;
  border-radius: 6px 6px;
  border: 1px solid #d9d9d9;
  background-color: #ffffff;
  color: #666;
  line-height: 1.5;
  -webkit-transform: border 0.3s cubic-bezier(0.35, 0, 0.25, 1), background 0.3s cubic-bezier(0.35, 0, 0.25, 1), box-shadow 0.3s cubic-bezier(0.35, 0, 0.25, 1);
  transform: border 0.3s cubic-bezier(0.35, 0, 0.25, 1), background 0.3s cubic-bezier(0.35, 0, 0.25, 1), box-shadow 0.3s cubic-bezier(0.35, 0, 0.25, 1);

  &:hover {
    border-color: #23c0fa;
  }

  &:focus {
    border-color: #23c0fa;
    box-shadow: 0 0 3px #23c0fa;
  }
}

.input() {
  position: relative;
  display: block;
  padding: @input-padding-vertical-base @input-padding-horizontal;
  width: 100%;
  font-size: @input-font-size;
  line-height: @line-height-base;
  color: @input-color;
  background-color: @input-bg;
  background-image: none;
  border: 1px solid @input-border-color;
  border-radius: @input-border-radius;
  // Reset placeholder
  .placeholder();
  .transition(~"border @{duration-300} @{ease-in-out}, background @{duration-300} @{ease-in-out}, box-shadow @{duration-300} @{ease-in-out}");

  &:not([disabled]):hover {
    border-color: @input-hover-border-color;
  }

  &:focus {
    @color-rgba: rgba(red(@input-focus-border-color), green(@input-focus-border-color), blue(@input-focus-border-color), .8);
    border-color: @input-focus-border-color;
    outline: 0;
    box-shadow: 0 0 3px @color-rgba;
  }

  &[disabled],
  &[readonly],
  fieldset[disabled] & {
    background-color: @input-disabled-bg;
    opacity: 1; 
  }

  &[disabled],
  fieldset[disabled] & {
    cursor: @cursor-disabled;
  }

  // Reset height for `textarea`s
  textarea& {
    height: auto;
  }

  // Size
  &-lg {
    padding: @input-padding-lg;
    font-size: @input-font-size-lg;
  }

  &-sm {
    padding: @input-padding-vertical-sm @input-padding-horizontal;
    font-size: @input-font-size-sm;
  }
}