:root {
    --bg: #fafbfc;
    --card: #fff;
    --text: #1a1a2e;
    --accent: #2563eb;
    --accent2: #7c3aed;
    --border: #e5e7eb;
    --green: #059669;
    --red: #dc2626;
    --orange: #d97706;
    --radius: 12px
}

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

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 20px
}

header {
    background: linear-gradient(135deg, #1e3a5f 0%, #2563eb 100%);
    color: #fff;
    padding: 48px 0;
    text-align: center
}

header h1 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 8px
}

header p {
    opacity: .85;
    font-size: 1rem
}

nav.toc {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    margin: 24px 0
}

nav.toc h2 {
    font-size: 1.1rem;
    margin-bottom: 12px;
    color: var(--accent)
}

nav.toc ol {
    padding-left: 20px
}

nav.toc li {
    margin: 4px 0
}

nav.toc a {
    color: var(--text);
    text-decoration: none;
    border-bottom: 1px dashed var(--border)
}

nav.toc a:hover {
    color: var(--accent);
    border-bottom-color: var(--accent)
}

section {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px;
    margin: 24px 0
}

section h2 {
    font-size: 1.4rem;
    color: var(--accent);
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--accent)
}

section h3 {
    font-size: 1.1rem;
    color: var(--accent2);
    margin: 20px 0 10px
}

.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px
}

.grid-3 {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 20px
}

@media(max-width:768px) {

    .grid-2,
    .grid-3 {
        grid-template-columns: 1fr
    }
}

.chart-box {
    background: var(--bg);
    border-radius: 8px;
    padding: 16px;
    text-align: center
}

.chart-box h4 {
    font-size: .85rem;
    margin-bottom: 8px;
    color: #555
}

.chart-box canvas {
    max-height: 260px
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 16px 0;
    font-size: .9rem
}

th,
td {
    padding: 8px 12px;
    border: 1px solid var(--border);
    text-align: left
}

th {
    background: #f0f4ff;
    font-weight: 600;
    color: var(--accent)
}

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

.formula-box {
    background: #f0f4ff;
    border-left: 4px solid var(--accent);
    border-radius: 0 8px 8px 0;
    padding: 16px 20px;
    margin: 16px 0
}

.formula-box .label {
    font-weight: 600;
    color: var(--accent);
    font-size: .85rem;
    margin-bottom: 4px
}

.excel-box {
    background: #fff8f0;
    border-left: 4px solid var(--orange);
    border-radius: 0 8px 8px 0;
    padding: 16px 20px;
    margin: 16px 0
}

.excel-box .label {
    font-weight: 600;
    color: var(--orange);
    font-size: .85rem;
    margin-bottom: 4px
}

.excel-box code {
    background: #fef3e2;
    padding: 2px 6px;
    border-radius: 4px;
    font-size: .85rem
}

.stat-card {
    background: var(--bg);
    border-radius: 8px;
    padding: 20px;
    text-align: center
}

.stat-card .value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent)
}

.stat-card .label {
    font-size: .85rem;
    color: #666
}

.badge {
    display: inline-block;
    padding: 2px 10px;
    border-radius: 12px;
    font-size: .8rem;
    font-weight: 600
}

.badge-green {
    background: #d1fae5;
    color: #065f46
}

.badge-yellow {
    background: #fef3c7;
    color: #92400e
}

.badge-red {
    background: #fee2e2;
    color: #991b1b
}