#include <bits/stdc++.h>
using namespace std;
long long t, n;
int main() {
  cin >> t;
  while (t--) {
    cin >> n;
    long long ls, mi = 0;
    bool pd = false;
    cin >> ls;
    for (int i = 2; i <= n; i++) {
      long long x, lg;
      cin >> x;
      if (x < ls) {
        lg = int(floor(log2(ls - x)));
        mi = max(mi, lg);
        pd = true;
      }
      ls = max(ls, x);
    }
    if (!pd)
      cout << 0 << endl;
    else
      cout << mi + 1 << endl;
  }
  return 0;
}
