body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    margin: 0;
    padding: 0;
}

.container {
    width: 80%;
    margin: auto;
    background: white;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.header img {
    width: 100%;
    display: block;
}

.nav {
    background: #0073e6;
    padding: 10px 0;
}

.nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    color: white;
}

.nav ul a {
    text-decoration: none;
    color: white;
    font-weight: bold;
    padding: 10px;
}

.nav a:hover {
    background: #005bb5;
    border-radius: 5px;
}

.adside {
    display: flex;
    gap: 20px;
    padding: 20px;
}

.left {
    width: 15%;
    background: #eee;
    padding: 5px;
    border-radius: 5px;
}

.right {
    width: 85%;
    background: #fff;
    padding: 20px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    border-radius: 5px;
}

.footer {
    text-align: center;
    background: #ffcccc;
    padding: 10px;
    margin-top: 20px;
}

.form-container {
    width: 80%;
    max-width: 400px;
    padding: 20px;
}

.form-container h2 {
    text-align: center;
    color: #333;
}

.form-container input {
    width: 100%;
    padding: 10px;
    margin: 10px 0;
}

.form-container button {
    width: 100%;
    padding: 10px;
    background: #0073e6;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 16px;
}

.form-container button:hover {
    background: #005bb5;
}

.adside {
    display: flex;
    gap: 20px;
    margin: 20px;
}

form {
    width: 400px;
    margin: 20px auto;
}

form h3 {
    text-align: center;
    margin-bottom: 15px;
}

form label {
    display: inline-block;
    width: 120px;
    margin-bottom: 10px;
    vertical-align: top;
}

form input[type="text"],
form input[type="file"],
form input[type="number"],
form select {
    width: 250px;
    padding: 5px;
    margin-bottom: 10px;
}

form button {
    padding: 8px 12px;
    margin-right: 10px;
    cursor: pointer;
}

table {
    width: 100%;
    /* border-collapse: collapse; */
    table-layout: fixed;
}

th,
td {
    border: 1px solid #ccc;
    padding: 5px;
    text-align: center;
    word-wrap: break-word;
}

.dropdown .button {
    padding: 10px 16px;
    background: #3498db;
    color: #fff;
    cursor: pointer;
    border-radius: 4px;
    width: 100%;
    /* chiếm toàn bộ chiều ngang li */
    box-sizing: border-box;
}

.menu a {
    display: block;
    padding: 10px 14px;
    color: #333;
    text-decoration: none;
    white-space: nowrap;
    /* không xuống dòng */
}

.menu a:hover {
    background: #a0c1d4;
}

.dropdown {
    position: relative;
    padding: 5px;
}

.dropdown:hover .menu {
    display: block;
}

.menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    background: white;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    min-width: 100px;
    z-index: 1000;
}