#include <bits/stdc++.h>
using namespace std;
const int INF = 2147483647;
const int INF2 = 0x3f3f3f3f;
const long long INF64 = 1e18;
const double INFD = 1e30;
const double EPS = 1e-9;
const double PI = acos(-1);
const int MOD = 998244353;
template <typename T>
inline T read() {
  T X = 0, w = 0;
  char ch = 0;
  while (!isdigit(ch)) {
    w |= ch == '-';
    ch = getchar();
  }
  while (isdigit(ch)) X = (X << 3) + (X << 1) + (ch ^ 48), ch = getchar();
  return w ? -X : X;
}
const int MAXN = 100005;
int n, m, k;
int dr[4] = {1, 0, -1, 0};
int dc[4] = {0, 1, 0, -1};
int dr2[8] = {1, 1, 1, -1, -1, -1, 0, 0};
int dc2[8] = {1, 0, -1, 1, 0, -1, 1, -1};
int CASE = 1;
int arr[MAXN];
void solve() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &arr[i]);
  }
  int curmax = arr[1];
  int num = 0;
  for (int i = 2; i <= n; i++) {
    if (arr[i] < curmax) {
      num = max(num, curmax - arr[i]);
    }
    curmax = max(curmax, arr[i]);
  }
  if (!num) {
    printf("0\n");
  } else {
    long long ans = 0;
    for (long long i = 1; i <= num; i *= 2) {
      ans++;
    }
    printf("%lld\n", ans);
  }
}
int main() {
  int T = read<int>();
  while (T--) {
    solve();
  }
  return 0;
}
