#include <bits/stdc++.h>
using namespace std;
long long v2[34];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int t;
  cin >> t;
  for (int i = 0; i <= 33; ++i) {
    if (i == 0) {
      v2[i] = 1;
    } else {
      v2[i] = 2 * v2[i - 1];
    }
  }
  while (t--) {
    int n;
    cin >> n;
    vector<long long> v(n);
    for (int i = 0; i < n; ++i) {
      cin >> v[i];
    }
    int ans = 0;
    for (int i = 1; i < n; ++i) {
      if (v[i] < v[i - 1]) {
        long long aux = 0;
        int k = 0;
        long long dif = v[i - 1] - v[i];
        for (int j = 0; j < 34; ++j) {
          aux += v2[j];
          if (aux >= dif) {
            ans = max(ans, j + 1);
            k = j;
            break;
          }
        }
        v[i] += dif;
      }
    }
    cout << ans << endl;
  }
  return 0;
}
