* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial, "Hiragino Sans", "Yu Gothic", sans-serif;
    background: #f4f6f8;
    color: #1f2937;
}

header {
    background: #111827;
    color: #fff;
    padding: 16px 24px;
}

.logo {
    font-size: 20px;
    font-weight: bold;
    margin-bottom: 12px;
}

nav {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

nav a {
    color: #e5e7eb;
    text-decoration: none;
    padding: 8px 12px;
    background: #1f2937;
    border-radius: 8px;
}

nav a:hover {
    background: #374151;
}

main {
    padding: 32px;
}

h1 {
    margin-top: 0;
}

.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
    margin-top: 24px;
}

.card {
    display: block;
    background: #fff;
    color: #111827;
    text-decoration: none;
    border-radius: 14px;
    padding: 24px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.card:hover {
    transform: translateY(-2px);
}

.card h2 {
    margin-top: 0;
    font-size: 20px;
}

.panel {
    background: #fff;
    border-radius: 14px;
    padding: 24px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

table {
    width: 100%;
    border-collapse: collapse;
    background: #fff;
    border-radius: 14px;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

th, td {
    padding: 14px;
    border-bottom: 1px solid #e5e7eb;
    text-align: left;
}

th {
    background: #f9fafb;
}

.login-body {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: #111827;
}

.login-card {
    width: 380px;
    background: #fff;
    padding: 32px;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.25);
}

.login-card h1 {
    margin-bottom: 8px;
}

.login-card p {
    color: #6b7280;
}

label {
    display: block;
    margin-top: 18px;
    margin-bottom: 6px;
    font-weight: bold;
}

input {
    width: 100%;
    padding: 12px;
    border: 1px solid #d1d5db;
    border-radius: 8px;
}

button {
    width: 100%;
    margin-top: 24px;
    padding: 12px;
    background: #2563eb;
    color: #fff;
    border: none;
    border-radius: 8px;
    font-weight: bold;
    cursor: pointer;
}

button:hover {
    background: #1d4ed8;
}

.error {
    background: #fee2e2;
    color: #991b1b;
    padding: 10px;
    border-radius: 8px;
    margin: 16px 0;
}