/* Toàn trang */
body {
  background: url('assets/images/background.jpg') no-repeat center center fixed;
  background-size: cover;
  font-family: 'Open Sans', sans-serif;
  color: #fff;
  margin: 0;
  height: 100vh;
  overflow-x: hidden;
}

/* Navbar */
.navbar {
  background: rgba(255, 255, 255, 0.2);
  backdrop-filter: blur(10px);
  box-shadow: 0 0 15px rgba(0, 0, 0, 0.3);
  padding-top: 18px !important;
  padding-bottom: 18px !important;
  border-bottom: 2px solid rgba(0,0,0,0.2);
}

.navbar-nav .nav-link {
  color: #111 !important;
  font-weight: 600;
  font-size: 16px;
  border: 2px solid #000;
  border-radius: 8px;
  padding: 8px 16px;
  margin: 0 4px;
  background: rgba(255,255,255,0.85);
  transition: all 0.3s ease;
  text-transform: uppercase;
}

.navbar-nav .nav-link:hover {
  background-color: #000;
  color: #fff !important;
  transform: scale(1.07);
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
}

/* Logo */
.logo-img {
  height: 190px;
  transition: 0.3s;
}
.logo-img:hover {
  transform: scale(1.05);
}
.navbar-brand img {
  margin-top: 10px; 
  transition: all 0.3s ease;
}

/* Căn vị trí form */
.auth-layout {
  margin-top: 120px; 
}

/* Khung form */
.card.card-body {
  width: 420px;
  max-width: 90%;
  margin: 0 auto;
  padding: 35px 40px;
  border-radius: 25px;
  background: rgba(255, 255, 255, 0.5);
  box-shadow: 0 0 30px rgba(0, 200, 255, 0.4);
  backdrop-filter: blur(12px);
}

/* Tiêu đề form */
.card.card-body h3 {
  font-size: 26px;
  color: #007bff;
  font-weight: bold;
  text-align: center;
  margin-bottom: 25px;
}

/* Input */
.form-control {
  font-size: 15px;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid #ccc;
  transition: 0.3s;
}
.form-control:focus {
  border-color: #007bff;
  box-shadow: 0 0 8px rgba(0, 150, 255, 0.3);
}

/* Checkbox */
.form-check {
  margin: 12px 0;
  text-align: left;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: #007bff;
}

/* Link quên mật khẩu */
.form-group.text-center.mb-3 a {
  color: #ff4444;
  font-weight: 600;
  text-decoration: none;
}
.form-group.text-center.mb-3 a:hover {
  text-decoration: underline;
  color: #ffcc00;
}

/* Nút */
.btn-primary {
  font-size: 16px;
  padding: 10px;
  border-radius: 8px;
  transition: 0.3s;
  background: linear-gradient(90deg, #007bff, #00bfff);
  border: none;
  box-shadow: 0 3px 8px rgba(0, 123, 255, 0.3);
}
.btn-primary:hover {
  transform: scale(1.05);
  box-shadow: 0 6px 15px rgba(0, 191, 255, 0.5);
}

/* Dòng "Bạn chưa có tài khoản?" */
.form-group_dk {
  text-align: center;
  margin-top: 10px;
}
.form-group_dk a {
  font-size: 15px;
  text-decoration: none;
  transition: all 0.3s ease;
  color: #ff3333; 
}
.form-group_dk a strong.text-primary {
  color: #00bfff; 
  font-weight: 700;
}
.form-group_dk a:hover strong.text-primary {
  color: #ffcc00; 
  text-shadow: 0 0 8px rgba(255, 255, 255, 0.9);
}

/* Hiệu ứng tuyết */
.snow-container {
  position: fixed;
  top: 0;
  left: 0;
  pointer-events: none;
  width: 100%;
  height: 100%;
  overflow: hidden;
  z-index: 9999;
}
.snowflake {
  position: absolute;
  top: -10px;
  color: #fff;
  animation: fall linear infinite;
}
@keyframes fall {
  0% { transform: translateY(0) rotate(0deg); }
  100% { transform: translateY(100vh) rotate(360deg); }
}