::v-deep {.el-input--medium,.el-input__inner {height: 100%;background: #163670;border: 1px solid #4cc0f6;border-radius: 6px 6px 6px 6px;&::placeholder {color: #13EFFF;}}
}

效果如下：

.el-date-editor .el-range-input{&::placeholder {color: #13efff;}}

效果如下：