:root {
    --primary-bg: #f7f9fc;
    --card-bg: #ffffff;
    --border-color: #e5e7eb;
    --accent: #3b82f6;
    --text-color: #1f2937;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 24px 12px 48px;
    font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--primary-bg);
    color: var(--text-color);
}

.page-container {
    max-width: 860px;
    margin: 0 auto;
    background: var(--card-bg);
    padding: 28px 24px;
    border-radius: 16px;
    box-shadow: 0 8px 28px rgba(0, 0, 0, 0.06);
    border: 1px solid var(--border-color);
}

.top-nav {
    display: flex;
    gap: 12px;
    align-items: center;
    justify-content: flex-start;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

.top-nav a,
.top-nav button {
    color: var(--accent);
    font-weight: 600;
    text-decoration: none;
    background: transparent;
    border: 1px solid var(--accent);
    border-radius: 10px;
    padding: 8px 14px;
    cursor: pointer;
    transition: background 0.15s ease, color 0.15s ease, box-shadow 0.15s ease;
}

.top-nav button {
    color: #fff;
    background: var(--accent);
}

.top-nav a:hover,
.top-nav button:hover {
    background: #e3ecff;
    color: #1d4ed8;
    box-shadow: 0 4px 10px rgba(59, 130, 246, 0.2);
}

h1, h2, h3 {
    margin-top: 0;
}

.section-card {
    padding: 16px;
    border-radius: 12px;
    background: #f9fafb;
    border: 1px solid var(--border-color);
    margin-bottom: 16px;
}

.age-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 6px 12px;
    border-radius: 999px;
    background: linear-gradient(135deg, #eef2ff, #e0f2fe);
    color: #1e3a8a;
    font-weight: 700;
    min-width: 64px;
    text-align: center;
    border: 1px solid #c7d2fe;
}

.list-stack {
    list-style: none;
    padding: 0;
    margin: 0;
    display: grid;
    gap: 12px;
}

.card-row {
    padding: 16px;
    border-radius: 14px;
    border: 1px solid var(--border-color);
    background: #ffffff;
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.05);
}

.form-grid {
    display: grid;
    gap: 12px;
}

label {
    font-weight: 600;
    display: block;
    margin-bottom: 6px;
}

input, textarea, select {
    width: 100%;
    padding: 10px 12px;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    font-size: 14px;
}

button[type="submit"],
button[type="button"] {
    background: var(--accent);
    color: #fff;
    padding: 10px 16px;
    border: none;
    border-radius: 10px;
    font-weight: 700;
    cursor: pointer;
    transition: background 0.15s ease, box-shadow 0.15s ease;
}

button[type="submit"]:hover,
button[type="button"]:hover {
    background: #1d4ed8;
    box-shadow: 0 6px 14px rgba(59, 130, 246, 0.35);
}

.helper-text {
    color: #4b5563;
}

.message-success {
    color: #15803d;
    font-weight: 700;
}

.message-error {
    color: #b91c1c;
    font-weight: 700;
}