/* Chủ đề Ninja School - Xanh lam bạc */
body {
  font-family: 'Poppins', sans-serif;
  background: radial-gradient(circle at center, #0b1e34, #060d18);
  color: #e0e8ff;
  margin: 0;
  padding: 0;
  overflow-x: hidden;
}

canvas#ninjaCanvas {
  position: fixed;
  top: 0;
  left: 0;
  z-index: -1;
}

h1, h2, h3 {
  color: #7fd2ff;
  text-shadow: 0 0 8px #5eb6ff;
}

.card {
  background: rgba(15, 25, 40, 0.8);
  border: 1px solid #3b6ea5;
  border-radius: 15px;
  padding: 20px;
  margin: 15px;
  box-shadow: 0 0 12px rgba(100,150,255,0.2);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 0 20px rgba(130,190,255,0.4);
}

button {
  background: linear-gradient(90deg, #2d74d4, #4fb0ff);
  border: none;
  border-radius: 8px;
  color: #fff;
  padding: 10px 18px;
  cursor: pointer;
  font-weight: 600;
  box-shadow: 0 0 10px rgba(79,176,255,0.5);
  transition: background 0.3s, transform 0.2s;
}
button:hover {
  background: linear-gradient(90deg, #4fb0ff, #6fd6ff);
  transform: scale(1.05);
}

input, select {
  background: #102540;
  border: 1px solid #357ebd;
  border-radius: 6px;
  color: #fff;
  padding: 10px;
  width: 100%;
  box-sizing: border-box;
}

.container {
  max-width: 900px;
  margin: 80px auto;
  text-align: center;
}

.navbar {
  background: rgba(10,20,35,0.8);
  padding: 10px 20px;
  border-bottom: 1px solid #3b6ea5;
  box-shadow: 0 0 8px rgba(100,150,255,0.2);
}
.navbar a {
  color: #a8d4ff;
  text-decoration: none;
  margin: 0 10px;
}
.navbar a:hover {
  color: #fff;
}