#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    long long ma = -1e15, need = 0;
    for (int i = 0; i < n; i++) {
      long long a;
      cin >> a;
      ma = max(a, ma);
      need = max(need, ma - a);
    }
    long long ans = 0;
    while ((1ll << ans) - 1 < need) ans++;
    cout << ans << endl;
  }
}
