:root {
    --bg: #f9f8f6;
    --surface: #ffffff;
    --border: #e2e0db;
    --text-primary: #1a1a1a;
    --text-secondary: #555550;
    --text-muted: #999;
    --accent: #2a2a2a;
    --line-simple: #1a1a1a;
    --line-compound: #888;
    --max-width: 768px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    background: var(--bg);
    color: var(--text-primary);
    font-family: "Source Sans 3", sans-serif;
    font-weight: 400;
    font-size: 20px;
    line-height: 1.75;
}

/* ── Layout ── */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* ── Header ── */
header {
    padding: 72px 0 48px;
    border-bottom: 1px solid var(--border);
}

.byline {
    font-size: 14px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 20px;
}

h1 {
    font-family: "Lora", Georgia, serif;
    font-size: clamp(2rem, 5vw, 2.8rem);
    font-weight: 600;
    line-height: 1.2;
    color: var(--text-primary);
    margin-bottom: 20px;
}

.subtitle {
    font-size: 1.2rem; /* Increased for better intro impact */
    color: var(--text-secondary);
    max-width: 65ch; /* Better line length for reading */
    line-height: 1.6;
}

.meta {
    margin-top: 28px;
    font-size: 13px;
    color: var(--text-muted);
    display: flex;
    gap: 20px;
}

/* ── Table of Contents ── */
.toc {
    margin: 48px 0;
    padding: 28px 32px;
    border: 1px solid var(--border);
    background: var(--surface);
}

.toc-title {
    font-size: 14px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 14px;
}

.toc ol {
    list-style: none;
    counter-reset: toc-counter;
}

.toc li {
    counter-increment: toc-counter;
    display: flex;
    align-items: baseline;
    gap: 10px;
    padding: 5px 0;
    border-bottom: 1px solid var(--border);
}

.toc li:last-child {
    border-bottom: none;
}

.toc li::before {
    content: counter(toc-counter, decimal-leading-zero);
    font-size: 13px; /* Slightly larger for visibility */
    color: var(--text-muted);
    font-variant-numeric: tabular-nums;
    flex-shrink: 0;
}

.toc a {
    color: var(--text-primary);
    text-decoration: none;
    font-size: 1.1rem; /* Increased from 0.95rem */
    transition: color 0.15s;
}

.toc a:hover {
    color: var(--text-muted);
}

/* ── Article body ── */
article {
    padding: 56px 0 96px;
}

section {
    margin-bottom: 64px;
}

h2 {
    font-family: "Lora", Georgia, serif;
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 20px;
    padding-top: 8px;
}

h3 {
    font-family: "Source Sans 3", sans-serif;
    font-size: 15px;
    font-weight: 600;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 16px;
}

p {
    color: var(--text-secondary);
    font-size: 1.2rem; /* This will now respect your body's 20px */
    margin-bottom: 24px;
}

p:last-child {
    margin-bottom: 0;
}

strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* ── Formula block ── */
.formula-block {
    margin: 28px 0;
    padding: 24px 28px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-left: 3px solid var(--text-primary);
}

.formula-label {
    font-size: 14px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 12px;
}

.formula {
    font-family: "Lora", Georgia, serif;
    font-size: 1.15rem;
    color: var(--text-primary);
    line-height: 1.6;
}

.formula sub,
.formula sup {
    font-size: 0.7em;
}

.formula-note {
    margin-top: 14px;
    font-size: 0.85rem;
    color: var(--text-muted);
    line-height: 1.5;
}

/* ── Comparison table ── */
.compare-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1px;
    background: var(--border);
    border: 1px solid var(--border);
    margin: 28px 0;
}

.compare-cell {
    background: var(--surface);
    padding: 20px 22px;
}

.compare-cell.header {
    background: var(--accent);
    color: white;
    font-size: 0.8rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.compare-cell p {
    font-size: 1.05rem; /* Increased from 0.9rem */
    margin: 0;
}

.compare-cell .amount {
    font-family: "Lora", serif;
    font-size: 1.6rem; /* Increased from 1.3rem */
    color: var(--text-primary);
    margin-bottom: 4px;
}

.compare-cell .amount.muted {
    color: var(--text-muted);
}

.compare-cell .diff {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* ── Chart section ── */
.chart-container {
    background: var(--surface);
    border: 1px solid var(--border);
    padding: 32px 28px;
    margin: 28px 0;
}

.sliders {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 20px;
    margin-bottom: 32px;
}

@media (max-width: 560px) {
    .sliders {
        grid-template-columns: 1fr;
    }
    .compare-grid {
        grid-template-columns: 1fr;
    }
}

.slider-group label {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    font-size: 14px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.slider-group label span {
    font-family: "Lora", serif;
    font-size: 1rem;
    text-transform: none;
    letter-spacing: 0;
    color: var(--text-primary);
}

input[type="range"] {
    width: 100%;
    height: 2px;
    background: var(--border);
    outline: none;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 14px;
    height: 14px;
    background: var(--text-primary);
    border-radius: 50%;
    cursor: pointer;
}

input[type="range"]::-moz-range-thumb {
    width: 14px;
    height: 14px;
    background: var(--text-primary);
    border-radius: 50%;
    border: none;
    cursor: pointer;
}

.chart-legend {
    display: flex;
    gap: 24px;
    margin-bottom: 20px;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.legend-dot {
    width: 24px;
    height: 2px;
    background: var(--line-simple);
}

.legend-dot.compound {
    background: var(--line-compound);
    border-top: 2px dashed var(--line-compound);
    height: 0;
}

canvas {
    width: 100% !important;
}

/* ── Result callout ── */
.result-callout {
    margin-top: 24px;
    padding: 18px 22px;
    background: var(--bg);
    border: 1px solid var(--border);
    font-size: 1.1rem;
    color: var(--text-secondary);
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.result-callout .item strong {
    display: block;
    font-size: 1.4rem;
    color: var(--text-primary);
}

/* ── Takeaway ── */
.takeaway {
    border-top: 1px solid var(--border);
    padding-top: 40px;
}

.takeaway blockquote {
    font-family: "Lora", Georgia, serif;
    font-size: 1.2rem;
    font-style: italic;
    color: var(--text-secondary);
    line-height: 1.65;
    border-left: 2px solid var(--border);
    padding-left: 20px;
    margin: 24px 0;
}

/* ── Footer ── */
footer {
    border-top: 1px solid var(--border);
    padding: 32px 0 48px;
    font-size: 0.85rem;
    color: var(--text-muted);
}

footer a {
    color: var(--text-muted);
}

footer a:hover {
    color: var(--text-primary);
}

/* ── Loan table specific styles ── */
.loan-container {
    background: var(--surface);
    border: 1px solid var(--border);
    padding: 32px 28px;
    margin: 28px 0;
}

.table-wrap {
    overflow-x: auto;
    margin-top: 28px;
    max-height: 420px;
    overflow-y: auto;
    border: 1px solid var(--border);
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.88rem;
    font-variant-numeric: tabular-nums;
}

thead th {
    background: var(--accent);
    color: white;
    font-size: 11px;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    padding: 12px 14px;
    text-align: right;
    position: sticky;
    top: 0;
    z-index: 1;
}

thead th:first-child {
    text-align: center;
}

tbody tr:nth-child(even) {
    background: var(--bg);
}

tbody td {
    padding: 10px 14px;
    text-align: right;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border);
    font-size: 0.9rem;
}

tbody td:first-child {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.8rem;
}

tbody tr:last-child td {
    color: var(--text-primary);
    font-weight: 600;
    background: var(--surface);
    border-top: 2px solid var(--border);
    border-bottom: none;
}

.summary-row {
    display: flex;
    gap: 0;
    margin-top: 20px;
    border: 1px solid var(--border);
}

.summary-item {
    flex: 1;
    padding: 16px 18px;
    border-right: 1px solid var(--border);
}

.summary-item:last-child {
    border-right: none;
}

.summary-item .label {
    font-size: 11px;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 6px;
}

.summary-item .value {
    font-family: "Lora", serif;
    font-size: 1.15rem;
    color: var(--text-primary);
}

@media (max-width: 560px) {
    .summary-row {
        flex-direction: column;
    }
    .summary-item {
        border-right: none;
        border-bottom: 1px solid var(--border);
    }
    .summary-item:last-child {
        border-bottom: none;
    }
}