* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  background: #0f172a;
  color: #fff;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.container {
  width: 380px;
  background: #020617;
  padding: 20px;
  border-radius: 10px;
}

h1 {
  text-align: center;
  margin-bottom: 5px;
}

.subtitle {
  text-align: center;
  font-size: 13px;
  color: #94a3b8;
  margin-bottom: 20px;
}

.search-box {
  display: flex;
  gap: 10px;
}

.search-box input {
  flex: 1;
  padding: 10px;
  border-radius: 6px;
  border: none;
  outline: none;
}

.search-box button {
  padding: 10px 15px;
  border: none;
  border-radius: 6px;
  background: #22c55e;
  cursor: pointer;
  font-weight: bold;
}

.matrix {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-top: 20px;
}

.card {
  background: #020617;
  border: 1px solid #1e293b;
  padding: 15px;
  border-radius: 8px;
  text-align: center;
}

.card h3 {
  font-size: 14px;
  color: #94a3b8;
}

.card p {
  font-size: 22px;
  margin-top: 5px;
}

.easy { border-color: #22c55e; }
.medium { border-color: #facc15; }
.hard { border-color: #ef4444; }

.loader {
  margin: 20px auto;
  width: 30px;
  height: 30px;
  border: 4px solid #1e293b;
  border-top: 4px solid #22c55e;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

.hidden {
  display: none;
}

@keyframes spin {
  100% {
    transform: rotate(360deg);
  }
}