:root {
    --primary: #3498db;
    --primary-dark: #2980b9;
    --secondary: #2ecc71;
    --danger: #e74c3c;
    --warning: #f39c12;
    --light: #f8f9fa;
    --dark: #343a40;
    --border: #dee2e6;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    background-color: #f5f7fa;
    color: #333;
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 8px;
    box-shadow: var(--shadow);
    padding: 20px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border);
}

h1, h2 {
    color: var(--primary);
}

h2 {
    margin-top: 25px;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border);
}

.actions {
    display: flex;
    gap: 10px;
}

button {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.3s;
}

button:hover {
    background-color: var(--primary-dark);
}

button:disabled {
    background-color: #95a5a6;
    cursor: not-allowed;
}

.logout {
    background-color: var(--dark);
    color: white;
    text-decoration: none;
    padding: 8px 15px;
    border-radius: 4px;
    font-size: 14px;
}

.logout:hover {
    background-color: #23272b;
}

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

label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

input[type="text"],
input[type="password"],
input[type="number"],
select {
    width: 100%;
    padding: 8px 10px;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 16px;
}

.error {
    background-color: #ffebee;
    color: #c62828;
    padding: 15px;
    border-radius: 4px;
    margin-bottom: 20px;
    border-left: 4px solid #c62828;
}

.success {
    background-color: #e8f5e9;
    color: #2e7d32;
    padding: 15px;
    border-radius: 4px;
    margin-bottom: 20px;
    border-left: 4px solid #2e7d32;
}

.birthday-notice {
    background-color: #fffde7;
    color: #f57f17;
    padding: 10px 15px;
    border-radius: 4px;
    margin-bottom: 20px;
    border-left: 4px solid #f57f17;
    font-weight: bold;
}

.table-container {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 20px;
}

th, td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

th {
    background-color: var(--primary);
    color: white;
    font-weight: 600;
}

tr:hover {
    background-color: rgba(52, 152, 219, 0.05);
}

tr.birthday {
    background-color: #ffebee;
    font-weight: bold;
}

tr.birthday:hover {
    background-color: #fce4ec;
}

tfoot tr {
    background-color: #f8f9fa;
    font-weight: bold;
}