//#include<bits/stdc++.h>
#include<map>
#include<queue>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define int long long
using namespace std;
#define rep_1(i,m,n) for(int i=m;i<=n;i++)
#define mem(st) memset(st,0,sizeof st)
int read()
{
int res=0,ch,flag=0;
if((ch=getchar())=='-') //判断正负
flag=1;
else if(ch>='0'&&ch<='9') //得到完整的数
res=ch-'0';
while((ch=getchar())>='0'&&ch<='9')
res=res*10+ch-'0';
return flag?-res:res;
}
typedef long long ll;
typedef pair<int,int> pii;
typedef unsigned long long ull;
typedef pair<double,double> pdd;
const int inf = 0x3f3f3f3f;
const int N=1e5+10;
int a[N];
void work()
{
int n=read();
for(int i=1; i<=n; i++)
a[i]=read();
int ans=0;
for(int i=2; i<=n; i++)
{
if(a[i-1]<=a[i])
continue;
int l=1,r=33;
while(l<r)
{
int mid=(l+r)/2;
int res=(1ll<<mid)-1;
if(a[i-1]<=a[i]+res)
r=mid;
else
l=mid+1;
}
ans=max(ans,l);
a[i]=a[i-1];
}
printf("%d
",ans);
}
signed main()
{
int t;
cin>>t;
while(t--)
work();
return 0;
}