Android studio – Faild to resolve：com.android.support：design：26.0.1错误

"Failed to resolve: com.android.support:design:26.0.1".

我的android studio版本是3.0 beta 1.

我的gradle文件如下：

apply plugin: 'com.android.application'

android {
compileSdkVersion 26
buildToolsversion "26.0.1"
defaultConfig {
    applicationId "hojune.example"
    minSdkVersion 17
    targetSdkVersion 26
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'),'proguard-rules.pro'
    }
}
}

dependencies {
compile filetree(include: ['*.jar'],dir: 'libs')
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2',{
    exclude group: 'com.android.support',module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:26.+'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
testCompile 'junit:junit:4.12'
compile 'com.android.support:design:26.0.1'
}

我想把“设计”放到我的项目中,但我不能这样做.我该怎么做？