body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f4f6f8;
    color: #222;
}

header {
    background: #1f2937;
    color: white;
    padding: 20px;
    text-align: center;
}

header h1 {
    margin: 0;
}

nav {
    background: #111827;
    padding: 12px;
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

nav a {
    color: white;
    text-decoration: none;
    background: #374151;
    padding: 8px 12px;
    border-radius: 6px;
}

nav a:hover {
    background: #4b5563;
}

main {
    max-width: 1100px;
    margin: 20px auto;
    background: white;
    padding: 22px;
    border-radius: 10px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

footer {
    text-align: center;
    padding: 20px;
    color: #555;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 18px;
}

th, td {
    border: 1px solid #ddd;
    padding: 9px;
    text-align: left;
}

th {
    background: #e5e7eb;
}

tr:nth-child(even) {
    background: #f9fafb;
}

.btn, button {
    display: inline-block;
    background: #2563eb;
    color: white;
    padding: 8px 12px;
    border-radius: 6px;
    text-decoration: none;
    border: none;
    cursor: pointer;
    margin: 4px 2px;
}

.btn.danger {
    background: #dc2626;
}

.btn.secondary {
    background: #4b5563;
}

form {
    max-width: 650px;
}

label {
    display: block;
    margin-top: 14px;
    font-weight: bold;
}

input, select {
    width: 100%;
    padding: 9px;
    margin-top: 5px;
    border: 1px solid #bbb;
    border-radius: 6px;
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 15px;
}

.card {
    border: 1px solid #ddd;
    border-radius: 10px;
    padding: 15px;
    background: #f9fafb;
}

.notice {
    background: #ecfdf5;
    border: 1px solid #10b981;
    color: #065f46;
    padding: 10px;
    border-radius: 6px;
}