html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  font-family: "Poppins", sans-serif;
}

#bg-video {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: -1; /* video nằm dưới */
}

body {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  min-height: 100vh;
  padding: 30px;
  background: linear-gradient(135deg, #ffecd2, #fcb69f); /* fallback nếu video lỗi */
  overflow-y: auto; /* cho phép scroll nếu nội dung dài */
}

.container {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 900px;
}

.card {
  background: rgba(255,255,255,0.9);
  border-radius: 20px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.15);
  padding: 30px;
  margin-bottom: 20px;
  text-align: center;
  animation: fadeIn 0.8s ease-in-out;
}

/* text */
h2 {
  margin-bottom: 15px;
  color: #333;
}
h3 {
  margin: 10px 0;
  color: #444;
}

/* input, button */
input, button {
  width: 100%;
  padding: 12px;
  margin: 8px 0;
  border-radius: 10px;
  border: 1px solid #ddd;
  font-size: 16px;
  outline: none;
  transition: 0.3s;
}
input:focus {
  border-color: #f77f00;
  box-shadow: 0 0 5px #f77f00;
}
button {
  border: none;
  background: linear-gradient(135deg, #f77f00, #ffba08);
  color: white;
  cursor: pointer;
  font-weight: bold;
}
button:hover {
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(247,127,0,0.4);
}

/* bảng */
table {
  width: 100%;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}
th, td {
  padding: 10px;
  border: 1px solid #ddd;
  text-align: center;
}

/* hiệu ứng */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-10px); }
  to   { opacity: 1; transform: translateY(0); }
}