/* Reset CSS */
body, h1, h2, h3, p, ul, ol, li, form, input, button, select {
    margin: 0;
    padding: 0;
    box-sizing: border-box; 
}

body {
    font-family: Arial, sans-serif;
    background-color: #f5f5f5;
    color: #333;
    padding: 20px; 
}

/* Layout chính */
.container {
    max-width: 800px;
    margin: 0 auto;
    background: #fff;
    border: 1px solid #ddd;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    padding: 20px;
}

/* Tiêu đề */
h1 {
    text-align: center;
    font-size: 24px;
    margin-bottom: 20px;
    color: #007bff;
}

/* Form */
form {
    margin-bottom: 20px;
}

form label {
    font-weight: bold;
    display: block;
    margin-bottom: 8px;
    color: #555;
}

form input[type="text"], 
form select, 
form input[type="color"] {
    width: 100%;
    padding: 10px;
    margin-bottom: 20px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 16px;
}

form button {
    background-color: #007bff;
    color: #fff;
    border: none;
    padding: 10px 15px;
    border-radius: 5px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.3s;
}

form button:hover {
    background-color: #0056b3;
}

/* Bảng hiển thị */
table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 20px;
}

table th, table td {
    border: 1px solid #ddd;
    padding: 10px;
    text-align: left;
}

table th {
    background-color: #f4f4f4;
    color: #333;
}

table tr:nth-child(even) {
    background-color: #f9f9f9;
}

/* Thông báo */
.message {
    padding: 10px;
    margin-bottom: 20px;
    border-radius: 5px;
    font-size: 14px;
}

.message.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.message.error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

/* Button điều hướng */
.nav-buttons {
    text-align: center;
    margin-bottom: 20px;
}

.nav-buttons a {
    text-decoration: none;
    background-color: #007bff;
    color: #fff;
    padding: 10px 15px;
    border-radius: 5px;
    margin: 0 5px;
    font-size: 16px;
    display: inline-block;
    transition: background-color 0.3s;
    width: 100%;
}

.nav-buttons a:hover {
    background-color: #0056b3;
}

.button {
    border-radius: 20px;
    padding: 10px 20px;
    background-color: green;
    width: 100%;
    color: #fff;
    font-size: 18px;
}