jetpack compose - Row space between

MainActivity.kt

package com.cfsuman.jetpackcompose

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.activity.compose.setContent
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.*
import androidx.compose.material.*
import androidx.compose.runtime.*
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContent {
            GetScaffold()
        }
    }


    @Composable
    fun GetScaffold(){
        Scaffold(
            topBar = {TopAppBar(
                title = {Text(
                    "Compose - Row Space Between",
                    color = Color.White)},
                backgroundColor = Color(0xFF58427C)) },
            content = {MainContent()},
            backgroundColor = Color(0xFFEDEAE0)
        )
    }


    @Composable
    fun MainContent(){
        Row(
            modifier = Modifier
                .fillMaxWidth()
                .height(200.dp)
                .padding(12.dp),
            horizontalArrangement = Arrangement.spacedBy(12.dp)
        ) {
            Box(
                Modifier
                    .fillMaxSize()
                    .weight(1f)
                    .background(Color(0xFF89CFF0))
            )

            Box(
                Modifier
                    .fillMaxSize()
                    .weight(1f)
                    .background(Color(0xFFFF91AF))
            )

            Box(
                Modifier
                    .fillMaxSize()
                    .weight(1f)
                    .background(Color(0xFFFE6F5E))
            )
        }
    }


    @Preview
    @Composable
    fun ComposablePreview(){
        //GetScaffold()
    }
}