border-radius($input-border-radius, 0);\n\n  @include box-shadow($input-box-shadow);\n  @include transition($input-transition);\n\n  // Unstyle the caret on `<select>`s in IE10+.\n  &::-ms-expand {\n    background-color: transparent;\n    border: 0;\n  }\n\n  // Customize the `:focus` state to imitate native WebKit styles.\n  @include form-control-focus($ignore-warning: true);\n\n  // Placeholder\n  &::placeholder {\n    color: $input-placeholder-color;\n    // Override Firefox's unusual default opacity; see http...