* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    background-color: #f4f7f6;
    color: #333;
}

header {
    background-color: #2c3e50;
    color: #fff;
    padding: 1rem 0;
    text-align: center;
}

nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 20px;
}

nav a {
    color: #fff;
    text-decoration: none;
    font-weight: bold;
    font-size: 1.1rem;
    padding: 5px 10px;
    border-radius: 4px;
    transition: background-color 0.3s;
}

nav a:hover {
    background-color: #34495e;
}

.container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.content-section {
    background: #fff;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

h2 {
    margin-bottom: 1.5rem;
    color: #2c3e50;
    border-bottom: 2px solid #eee;
    padding-bottom: 0.5rem;
}

.form-group {
    margin-bottom: 1rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

input[type="text"] {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
}

.btn-primary {
    display: inline-block;
    background-color: #3498db;
    color: #fff;
    padding: 0.8rem 1.5rem;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: bold;
    transition: background-color 0.3s;
}

.btn-primary:hover {
    background-color: #2980b9;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

th, td {
    border: 1px solid #ddd;
    padding: 12px;
    text-align: left;
}

th {
    background-color: #f8f9fa;
    color: #2c3e50;
}

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

#empty-msg {
    text-align: center;
    color: #777;
    margin-top: 2rem;
}