body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: url('../img/nền.jpg') no-repeat center center/cover;
    min-height: 100vh;
    background-attachment: fixed;
    /* nền cố định khi cuộn */
    display: flex;
    flex-direction: column;
}

/* Thanh menu cố định trên cùng */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(74, 74, 138, 0.9);
    /* màu tím đậm hơi trong suốt */
    z-index: 1000;
}

/* Menu chính */
nav .menu {
    list-style: none;
    display: flex;
    justify-content: center;
    margin: 0;
    padding: 0;
}

nav .menu li {
    position: relative;
}

nav .menu li a {
    display: block;
    padding: 15px 20px;
    color: #fff;
    text-decoration: none;
}

nav .menu li:hover>a {
    background-color: #36365c;
}

/* Menu con (cấp 2) */
nav .menu li .sub-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    background-color: rgba(85, 85, 165, 0.95);
    list-style: none;
    min-width: 160px;
    margin: 0;
    padding: 0;
}

nav .menu li:hover .sub-menu {
    display: block;
}

nav .sub-menu li a {
    padding: 10px 15px;
    color: #fff;
}

nav .sub-menu li a:hover {
    background-color: #404066;
}

/* Nội dung chính */
main {
    max-width: 800px;
    margin: 120px auto 60px auto;
    /* khoảng cách trên = 120px để tránh bị menu đè */
    flex: 1;
    /* đẩy footer xuống cuối trang */
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
    text-align: center;
    background: rgba(115, 34, 75, 0.081);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
    color: rgb(255, 255, 255);
    backdrop-filter: blur(10px);
    border-radius: 25px;
    padding: 35px;
}

#main2 h1 {
    padding: 20px;
}

#main2 p {
    padding: 10px;
    text-align: justify;
}

/* Banner */
main img {
    width: 100%;
    height: auto;
    border-radius: 10px;
    margin-top: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}

/* Footer */
footer {
    text-align: center;
    background-color: rgba(74, 74, 138, 0.9);
    color: #fff;
}

/* Form tra cứu */
form label {
    display: block;
    margin: 10px 0 5px;
}

form input[type=number] {
    padding: 8px;
    width: 100%;
    max-width: 200px;
    margin-bottom: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
}

form button {
    padding: 10px 20px;
    background-color: #4a4a8a;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

form button:hover {
    background-color: #36365c;
}

/* form */
#form {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    padding-top: 80px;
    padding-bottom: 30px;
}

.card {
    background: rgba(115, 34, 75, 0.08);
    backdrop-filter: blur(10px);
    border-radius: 25px;
    padding: 30px;
    width: 400px;
    color: rgb(40, 3, 12);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
}

h2 {
    text-align: center;
    margin-bottom: 20px;
    color: rgb(40, 3, 12);
}

label {
    font-weight: bold;
    display: block;

}

input,
textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #555;
    border-radius: 10px;
    outline: none;
    font-size: 15px;
    box-sizing: border-box;
}

input:focus,
textarea:focus {
    border-color: #73224B;
    box-shadow: 0 0 5px #73224B;
}

input[type="submit"] {
    background: #73224B;
    color: #fff;
    border: none;
    cursor: pointer;
    transition: 0.3s;
    font-weight: bold;
}

input[type="submit"]:hover {
    background: #4e1532;
}

/* thongtin */
#tt {
    margin: 0;
    font-family: Arial, sans-serif;
    background: url('../img/nền.jpg') no-repeat center center/cover;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding-top: 80px;
}

#tt .card {
    background: rgba(115, 34, 75, 0.081);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
    color: rgb(40, 3, 12);
    backdrop-filter: blur(10px);
    border-radius: 25px;
    padding: 35px;
    width: 350px;
    text-align: center;
}

#tt .avatar {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    overflow: hidden;
    margin: 0 auto 20px;
    border: 2px solid black;
}

#tt .avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

#tt h2 {
    margin: 20px 0;
}

#tt p {
    margin: 10px 0;
}