body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f8f9fa;
    color: #333;
    margin: 0;
    padding: 0;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.auth-container {
    max-width: 400px;
    margin: 50px auto;
    background: #fff;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

h1, h2, h3 {
    color: #2c3e50;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 600;
}

.form-control, input[type="text"], input[type="password"], input[type="number"], select {
    width: 100%;
    padding: 10px;
    border: 1px solid #ced4da;
    border-radius: 4px;
    box-sizing: border-box;
}

.btn {
    display: inline-block;
    font-weight: 400;
    text-align: center;
    white-space: nowrap;
    vertical-align: middle;
    user-select: none;
    border: 1px solid transparent;
    padding: 0.375rem 0.75rem;
    font-size: 1rem;
    line-height: 1.5;
    border-radius: 0.25rem;
    cursor: pointer;
    text-decoration: none;
}

.btn-primary {
    color: #fff;
    background-color: #007bff;
    border-color: #007bff;
}

.btn-primary:hover {
    background-color: #0056b3;
    border-color: #004a99;
}

.btn-danger {
    color: #fff;
    background-color: #dc3545;
    border-color: #dc3545;
}

.btn-danger:hover {
    background-color: #c82333;
    border-color: #bd2130;
}

.alert {
    padding: 10px;
    margin-bottom: 15px;
    border-radius: 4px;
}

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

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

table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1rem;
    background-color: transparent;
}

table th, table td {
    padding: 0.75rem;
    vertical-align: top;
    border-top: 1px solid #dee2e6;
}

table thead th {
    vertical-align: bottom;
    border-bottom: 2px solid #dee2e6;
    text-align: left;
}

nav {
    background-color: #343a40;
    padding: 10px 20px;
}

nav a {
    color: #fff;
    text-decoration: none;
    margin-right: 15px;
}

nav a:hover {
    text-decoration: underline;
}

.footer {
    text-align: center;
    padding: 20px;
    margin-top: 40px;
    border-top: 1px solid #dee2e6;
    font-size: 14px;
}

.footer a {
    color: #007bff;
    text-decoration: none;
    margin: 0 10px;
}

.upload-area {
    border: 2px dashed #007bff;
    border-radius: 8px;
    padding: 40px;
    text-align: center;
    background-color: #f8f9fa;
    margin-bottom: 20px;
}