body {
    margin: 0;
    font-family: Inter, Arial, sans-serif;
    background: #f3f5f9;
    color: #1f2937;
}

.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 1.5rem;
    background: #2d3748;
    color: #f8fafc;
}

.app-header a {
    color: #e2e8f0;
    text-decoration: none;
    border: 1px solid rgba(226, 232, 240, 0.5);
    padding: 0.5rem 0.85rem;
    border-radius: 0.5rem;
}

.container {
    max-width: 900px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.card {
    background: #ffffff;
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
    border-radius: 1rem;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.card h2 {
    margin-top: 0;
}

label {
    display: block;
    margin-bottom: 0.4rem;
    font-weight: 600;
}

input[type="text"], input[type="password"], select, textarea {
    width: 100%;
    padding: 0.85rem 1rem;
    margin-bottom: 1rem;
    border: 1px solid #cbd5e1;
    border-radius: 0.75rem;
    background: #f8fafc;
    font-size: 1rem;
}

textarea {
    resize: vertical;
}

button, .button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.85rem 1.25rem;
    border: none;
    border-radius: 0.75rem;
    background: #2563eb;
    color: white;
    font-weight: 700;
    cursor: pointer;
    text-decoration: none;
}

button:hover, .button:hover {
    background: #1d4ed8;
}

table {
    width: 100%;
    border-collapse: collapse;
}

table th, table td {
    text-align: left;
    padding: 0.85rem 0.75rem;
    border-bottom: 1px solid #e2e8f0;
}

.alert {
    border-radius: 0.75rem;
    padding: 1rem;
    margin-bottom: 1rem;
}

.alert-error {
    background: #fef2f2;
    border: 1px solid #fecaca;
    color: #991b1b;
}

.alert-success {
    background: #ecfdf5;
    border: 1px solid #6ee7b7;
    color: #065f46;
}

.footnote {
    color: #475569;
    font-size: 0.95rem;
}

.question-block {
    margin-bottom: 1rem;
}

.child-block {
    margin-bottom: 1.5rem;
}