I cannot include material design library in my project
This is my build.gradle file
apply plugin: 'com.android.application'
android {
    compileSdkVersion 26
    buildToolsVersion "25.0.2"
    defaultConfig {
        applicationId "com.example.abdelmagied.myapplication"
        minSdkVersion 15
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:26.0.0-alpha1'
    compile 'com.android.support:design:26.0.0'
}
Every time I Sync it gives me this error:
Failed To resolve:com.android.support:design:26.0.0