/* Font và box model */
* {
  box-sizing: border-box;
  font-family: 'Inter', sans-serif;
  margin: 0;
  padding: 0;
}

body {
  height: 100vh;
  color: white;
  overflow-x: hidden;
}

/* Nền */
.background {
  position: fixed;
  top: 0; left: 0;
  width: 100vw;
  height: 100vh;
  background-image: url('https://4kwallpapers.com/images/walls/thumbs_3t/5889.jpg');
  background-size: cover;
  background-position: center;
  filter: blur(2px);
  z-index: -1;
}

/* Menu */
.menu {
  position: fixed;
  top: 0; left: 0;
  width: 100%;
  display: flex;
  justify-content: center;
  gap: 30px;
  padding: 5px 0;
  background-color: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(5px);
  border-bottom: 2px solid rgba(160, 160, 160, 0.72);
  z-index: 10;
}

.menu a {
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  font-weight: bold;
  padding: 8px 12px;
  border-radius: 6px;
  transition: all 0.3s ease;
}

.menu a:hover {
  background-color: rgba(255, 255, 255, 0.2);
  transform: scale(1.05);
}

/* Nội dung chính */
.body {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding-top: 80px;
  gap: 32px;
  flex-wrap: wrap;
}

/* Form */
form {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px;
  background-color: rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(6px);
  border-radius: 10px;
  border: 2px solid rgba(160, 160, 160, 0.72);
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
  min-width: 320px;
  max-width: 400px;
  width: 100%;
}

/* Input */
input, textarea {
  width: 100%;
  padding: 10px;
  font-size: 16px;
  border-radius: 6px;
  border: 2px solid rgba(160, 160, 160, 0.72);
  background-color: rgba(255, 255, 255, 0.1);
  color: white;
  outline: none;
  transition: border-color 0.3s ease;
}

input::placeholder, textarea::placeholder {
  color: rgba(255, 255, 255, 0.7);
  opacity: 1;
}

/* Checkbox label */
label {
  display: block;
  font-size: 14px;
  margin-bottom: 4px;
  color: #fff;
}

/* Nút gửi */
button {
  padding: 10px 20px;
  font-size: 16px;
  font-weight: bold;
  text-transform: uppercase;
  color: white;
  background-color: #222;
  border: 2px solid rgba(160, 160, 160, 0.72);
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.3s ease;
  text-align: center;
}

button:hover {
  background-color: #818181;
}

/* Ghi chú bên cạnh */
.note {
  max-width: 320px;
  background: rgba(255, 255, 255, 0.7);
  border-radius: 8px;
  padding: 16px;
  font-size: 15px;
  color: #333;
  line-height: 1.5;
}

/* reCAPTCHA fix spacing */
.g-recaptcha {
  transform: scale(0.96);
  transform-origin: 0 0;
}

/* Responsive */
@media (max-width: 768px) {
  .body {
    flex-direction: column;
    align-items: center;
  }
}