evalstate's picture
download
raw
58.8 kB
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Birch rendering checker — module explainer</title>
<style data-birch-system>/*
Birch HTML Design System
Opinionated single-option stylesheet for reliable LLM-generated artifacts.
Model:
1. Design tokens as CSS variables.
2. Layout primitives as classes.
3. Semantic components as classes with data-* variants.
*/
/* ==================== 1. TOKENS ==================== */
:root {
color-scheme: light;
/* Palette */
--color-ivory: #FAF9F5;
--color-slate: #141413;
--color-clay: #D97757;
--color-clay-dark: #B85C3E;
--color-oat: #E3DACC;
--color-olive: #788C5D;
--color-rust: #B04A3F;
--color-sky: #6A8CAF;
--color-white: #FFFFFF;
--color-gray-50: #F7F5EE;
--color-gray-100: #F0EEE6;
--color-gray-150: #E8E4DA;
--color-gray-200: #DED9CD;
--color-gray-300: #D1CFC5;
--color-gray-500: #87867F;
--color-gray-700: #3D3D3A;
--color-gray-800: #242421;
/* Semantic colors */
--bg: var(--color-ivory);
--surface: var(--color-white);
--surface-tint: var(--color-gray-100);
--surface-warm: var(--color-oat);
--text: var(--color-slate);
--text-muted: var(--color-gray-500);
--text-soft: var(--color-gray-700);
--muted: var(--text-muted);
--border-color: var(--color-gray-300);
--accent: var(--color-clay);
--accent-strong: var(--color-clay-dark);
--success: var(--color-olive);
--warning: #C78E3F;
--danger: var(--color-rust);
--info: var(--color-sky);
/* Typography */
--font-serif: ui-serif, Georgia, "Times New Roman", serif;
--font-sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
--font-mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
--text-xs: 11px;
--text-sm: 12px;
--text-md: 14px;
--text-base: 15px;
--text-lg: 17px;
--text-xl: 21px;
--text-2xl: 26px;
--text-3xl: 36px;
--text-4xl: 44px;
--leading-tight: 1.15;
--leading-title: 1.25;
--leading-body: 1.55;
--leading-loose: 1.7;
/* Spacing */
--space-1: 4px;
--space-2: 8px;
--space-3: 12px;
--space-4: 16px;
--space-5: 24px;
--space-6: 32px;
--space-7: 48px;
--space-8: 64px;
--space-9: 96px;
/* Shape */
--radius-xs: 4px;
--radius-sm: 8px;
--radius-md: 12px;
--radius-lg: 16px;
--radius-xl: 20px;
--radius-pill: 999px;
--border: 1.5px solid var(--border-color);
--border-thin: 1px solid var(--border-color);
--shadow-sm: 0 1px 2px rgba(20, 20, 19, 0.06);
--shadow-md: 0 4px 14px rgba(20, 20, 19, 0.08);
--shadow-lg: 0 12px 28px rgba(20, 20, 19, 0.12);
/* Motion */
--ease: cubic-bezier(0.2, 0, 0, 1);
--ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
--dur-fast: 120ms;
--dur: 180ms;
--hover-y: -2px;
/* Page sizing */
--page-max: 1100px;
--page-pad: 28px;
--page-pad-block: 48px;
/* Legacy aliases used by source examples */
--ivory: var(--color-ivory);
--slate: var(--color-slate);
--clay: var(--color-clay);
--clay-d: var(--color-clay-dark);
--oat: var(--color-oat);
--olive: var(--color-olive);
--rust: var(--color-rust);
--sky: var(--color-sky);
--white: var(--color-white);
--gray-50: var(--color-gray-50);
--gray-100: var(--color-gray-100);
--gray-150: var(--color-gray-150);
--gray-200: var(--color-gray-200);
--gray-300: var(--color-gray-300);
--gray-500: var(--color-gray-500);
--gray-700: var(--color-gray-700);
--gray-800: var(--color-gray-800);
--serif: var(--font-serif);
--sans: var(--font-sans);
--mono: var(--font-mono);
}
/* ==================== BASE ==================== */
*,
*::before,
*::after {
box-sizing: border-box;
}
html {
background: var(--bg);
color: var(--text);
font-family: var(--font-sans);
-webkit-text-size-adjust: 100%;
}
body {
margin: 0;
background: var(--bg);
color: var(--text);
font-family: var(--font-sans);
font-size: var(--text-base);
line-height: var(--leading-body);
-webkit-font-smoothing: antialiased;
text-rendering: optimizeLegibility;
}
img,
svg {
max-width: 100%;
}
a {
color: inherit;
text-decoration-color: rgba(217, 119, 87, 0.45);
text-underline-offset: 3px;
}
a:hover {
color: var(--accent);
}
h1,
h2,
h3,
p {
margin-block: 0;
}
h1,
h2,
h3 {
font-family: var(--font-serif);
font-weight: 500;
letter-spacing: -0.01em;
line-height: var(--leading-title);
}
h1 {
font-size: clamp(32px, 5vw, var(--text-4xl));
}
h2 {
font-size: var(--text-2xl);
}
h3 {
font-size: var(--text-xl);
}
code,
kbd,
pre {
font-family: var(--font-mono);
}
code {
font-size: 0.92em;
white-space: normal;
word-break: normal;
}
h1 code,
h2 code,
h3 code {
overflow-wrap: anywhere;
word-break: break-word;
}
button,
input,
textarea,
select {
font: inherit;
}
button {
cursor: pointer;
}
::selection {
background: rgba(217, 119, 87, 0.24);
}
/* ==================== 2. LAYOUT PRIMITIVES ==================== */
.page {
width: min(100% - (var(--page-pad) * 2), var(--page-max));
margin-inline: auto;
padding-block: var(--page-pad-block) var(--space-9);
}
.page[data-size="narrow"] {
--page-max: 820px;
}
.page[data-size="wide"] {
--page-max: 1280px;
}
.page[data-size="full"] {
--page-max: 1440px;
}
.section {
margin-block: var(--section-gap, var(--space-5));
}
.section[data-gap="lg"] {
--section-gap: var(--space-6);
}
.section[data-gap="xl"] {
--section-gap: var(--space-7);
}
.section:first-child {
margin-block-start: 0;
}
.stack > .section {
margin-block: 0;
}
.rule {
border: 0;
border-top: var(--border-thin);
margin: var(--space-3) 0 var(--space-5);
}
.stack {
display: flex;
flex-direction: column;
gap: var(--stack-gap, var(--space-4));
}
.stack[data-gap="xs"] { --stack-gap: var(--space-2); }
.stack[data-gap="sm"] { --stack-gap: var(--space-3); }
.stack[data-gap="md"] { --stack-gap: var(--space-4); }
.stack[data-gap="lg"] { --stack-gap: var(--space-6); }
.stack[data-gap="xl"] { --stack-gap: var(--space-8); }
.stack > :is(.button, .btn, .chip, .badge) {
align-self: flex-start;
}
.cluster {
display: flex;
flex-wrap: wrap;
align-items: center;
gap: var(--cluster-gap, var(--space-3));
}
.cluster[data-align="start"] { align-items: flex-start; }
.cluster[data-align="end"] { align-items: flex-end; }
.cluster[data-justify="between"] { justify-content: space-between; }
.cluster[data-justify="end"] { justify-content: flex-end; }
.grid {
display: grid;
gap: var(--grid-gap, var(--space-5));
}
.grid[data-cols="2"] {
grid-template-columns: repeat(2, minmax(0, 1fr));
}
.grid[data-cols="3"] {
grid-template-columns: repeat(3, minmax(0, 1fr));
}
.grid[data-cols="4"] {
grid-template-columns: repeat(4, minmax(0, 1fr));
}
.auto-grid {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(min(100%, var(--grid-min, 240px)), 1fr));
gap: var(--grid-gap, var(--space-5));
}
.auto-grid > * {
min-width: 0;
}
.split {
display: grid;
grid-template-columns: minmax(0, 1fr) minmax(280px, var(--split-side, 360px));
gap: var(--split-gap, var(--space-6));
align-items: start;
}
.split > * {
min-width: 0;
}
.section-head {
min-width: 0;
}
.section-rail {
display: grid;
grid-template-columns: minmax(0, 1fr) minmax(280px, var(--rail-width, 360px));
column-gap: var(--rail-gap, var(--space-6));
row-gap: var(--space-5);
align-items: start;
}
.section-rail > .section-head {
grid-column: 1 / -1;
}
.section-rail > .reference-panel,
.section-rail > aside {
align-self: start;
}
.sidebar-layout {
display: grid;
grid-template-columns: var(--sidebar-width, 240px) minmax(0, 1fr);
gap: var(--sidebar-gap, var(--space-7));
align-items: start;
}
.sidebar-layout > :first-child,
.sticky {
position: sticky;
top: var(--sticky-top, var(--space-5));
}
.bleed {
margin-inline: calc(var(--page-pad) * -1);
}
.scroll-x {
overflow-x: auto;
overscroll-behavior-inline: contain;
}
.center {
display: grid;
place-items: center;
}
.spacer {
flex: 1;
}
@media (max-width: 860px) {
:root {
--page-pad: 20px;
--page-pad-block: 40px;
}
.grid[data-cols],
.split,
.section-rail,
.sidebar-layout {
grid-template-columns: 1fr;
}
.sidebar-layout > :first-child,
.sticky {
position: static;
}
}
/* ==================== TYPOGRAPHY UTILITIES ==================== */
.eyebrow {
display: inline-flex;
align-items: center;
gap: var(--space-2);
color: var(--accent);
font-family: var(--font-mono);
font-size: var(--text-xs);
font-weight: 700;
letter-spacing: 0.08em;
text-transform: uppercase;
}
.eyebrow::before {
content: "";
width: 24px;
height: 1.5px;
background: currentColor;
}
.lede {
max-width: 720px;
color: var(--text-soft);
font-size: var(--text-lg);
line-height: 1.6;
}
.muted {
color: var(--text-muted);
}
.caption {
color: var(--text-muted);
font-family: var(--font-mono);
font-size: var(--text-sm);
}
.stat-value {
display: block;
color: var(--text);
font-family: var(--font-serif);
font-size: clamp(30px, 3.2vw, 42px);
font-variant-numeric: tabular-nums;
font-weight: 550;
letter-spacing: -0.025em;
line-height: 1;
}
.stat-card {
gap: var(--space-2);
}
.stat-card .caption {
letter-spacing: 0.08em;
text-transform: uppercase;
}
.stat-card .muted {
max-width: 34ch;
font-size: var(--text-sm);
}
.mono {
font-family: var(--font-mono);
}
/* ==================== 3. SEMANTIC COMPONENTS ==================== */
.panel,
.card {
background: var(--surface);
border: var(--border);
border-radius: var(--radius-md);
}
.panel {
padding: var(--panel-pad, var(--space-5));
}
.card {
padding: var(--card-pad, var(--space-5));
transition:
transform var(--dur-fast) var(--ease),
border-color var(--dur-fast) var(--ease),
box-shadow var(--dur-fast) var(--ease),
background-color var(--dur-fast) var(--ease);
}
.card[data-hover="lift"]:hover,
.card[data-clickable]:hover {
transform: translateY(var(--hover-y));
border-color: rgba(217, 119, 87, 0.55);
box-shadow: var(--shadow-md);
}
.card[data-clickable] {
cursor: pointer;
}
.card[data-variant="flat"] {
background: transparent;
border-color: transparent;
box-shadow: none;
}
.card[data-variant="outlined"] {
background: var(--surface);
border: var(--border);
}
.card[data-variant="elevated"] {
border-color: transparent;
box-shadow: var(--shadow-md);
}
.card[data-variant="filled"],
.card[data-tone="oat"] {
background: var(--surface-warm);
}
.card[data-tone],
.panel[data-tone],
.callout[data-tone] {
background: var(--surface);
}
.card[data-tone="danger"],
.panel[data-tone="danger"],
.callout[data-tone="danger"] {
border-color: rgba(176, 74, 63, 0.36);
}
.card[data-tone="warning"],
.panel[data-tone="warning"],
.callout[data-tone="warning"] {
border-color: rgba(199, 142, 63, 0.38);
}
.card[data-tone="success"],
.panel[data-tone="success"],
.callout[data-tone="success"] {
border-color: rgba(120, 140, 93, 0.38);
}
.card[data-tone="info"],
.panel[data-tone="info"],
.callout[data-tone="info"] {
border-color: rgba(106, 140, 175, 0.36);
}
.card[data-accent] {
position: relative;
overflow: hidden;
}
.card[data-accent]::before {
content: "";
position: absolute;
inset: 0 auto 0 0;
width: 5px;
background: var(--accent);
}
.card-head {
display: flex;
align-items: center;
gap: var(--space-3);
min-width: 0;
max-width: 100%;
}
.card-head > :first-child {
flex: 0 0 auto;
}
.card-titles {
flex: 1 1 0;
min-width: 0;
max-width: 100%;
}
.card-title {
max-width: 100%;
margin: 0;
font-family: var(--font-serif);
font-size: var(--text-xl);
font-weight: 550;
line-height: var(--leading-title);
overflow-wrap: anywhere;
}
.card-sub {
margin: 2px 0 0;
color: var(--text-muted);
font-size: var(--text-sm);
overflow-wrap: anywhere;
}
.toolbar {
display: flex;
flex-wrap: wrap;
align-items: center;
gap: var(--space-4);
padding: var(--space-4) var(--space-5);
background: var(--surface);
border: var(--border);
border-radius: var(--radius-md);
}
.toolbar[data-sticky] {
position: sticky;
top: 0;
z-index: 10;
}
.chip,
.badge {
display: inline-flex;
align-items: center;
justify-content: center;
gap: 6px;
border-radius: var(--radius-pill);
white-space: nowrap;
font-family: var(--font-mono);
font-size: var(--text-xs);
font-weight: 650;
line-height: 1;
}
.chip {
min-height: 24px;
padding: 0 10px;
color: var(--text-soft);
background: var(--surface-tint);
border: 1px solid transparent;
}
.badge {
min-height: 22px;
padding: 0 9px;
color: var(--text-muted);
background: var(--surface);
border: var(--border-thin);
text-transform: uppercase;
letter-spacing: 0.06em;
}
.chip[data-tone="clay"],
.badge[data-tone="clay"] {
color: var(--accent);
background: rgba(217, 119, 87, 0.14);
}
.chip[data-tone="olive"],
.badge[data-tone="olive"],
.chip[data-tone="success"],
.badge[data-tone="success"] {
color: var(--success);
background: rgba(120, 140, 93, 0.15);
}
.chip[data-tone="warning"],
.badge[data-tone="warning"] {
color: var(--warning);
background: rgba(199, 142, 63, 0.16);
}
.chip[data-tone="rust"],
.badge[data-tone="rust"],
.chip[data-tone="danger"],
.badge[data-tone="danger"] {
color: var(--danger);
background: rgba(176, 74, 63, 0.13);
}
.chip[data-tone="sky"],
.badge[data-tone="sky"],
.chip[data-tone="info"],
.badge[data-tone="info"] {
color: var(--info);
background: rgba(106, 140, 175, 0.14);
}
.finding {
border-left: 6px solid var(--border-color);
}
.finding[data-severity="blocker"],
.finding[data-severity="critical"],
.finding[data-severity="danger"],
.finding[data-tone="danger"] {
border-left-color: var(--danger);
}
.finding[data-severity="high"],
.finding[data-severity="warning"],
.finding[data-tone="warning"] {
border-left-color: var(--warning);
}
.finding[data-severity="medium"],
.finding[data-severity="info"],
.finding[data-tone="info"] {
border-left-color: var(--info);
}
.finding[data-severity="low"],
.finding[data-severity="success"],
.finding[data-tone="success"] {
border-left-color: var(--success);
}
.button,
.btn {
appearance: none;
display: inline-flex;
align-items: center;
justify-content: center;
min-height: 36px;
padding: 0 14px;
border: 1.5px solid transparent;
border-radius: var(--radius-sm);
font-family: var(--font-sans);
font-size: var(--text-md);
font-weight: 650;
line-height: 1;
text-decoration: none;
transition:
transform var(--dur-fast) var(--ease),
background-color var(--dur-fast) var(--ease),
border-color var(--dur-fast) var(--ease),
box-shadow var(--dur-fast) var(--ease);
}
.button:hover,
.btn:hover {
transform: translateY(-1px);
}
.button[data-variant="primary"],
.btn-primary {
color: var(--color-white);
background: var(--color-slate);
}
.button[data-variant="primary"]:hover,
.btn-primary:hover {
background: var(--color-gray-700);
}
.button[data-variant="secondary"],
.btn-secondary {
color: var(--text);
background: var(--surface-tint);
border-color: var(--border-color);
}
.button[data-variant="ghost"],
.btn-ghost {
color: var(--text-soft);
background: transparent;
}
.button[data-variant="ghost"]:hover,
.btn-ghost:hover {
color: var(--text);
background: var(--surface-tint);
}
.button[data-variant="danger"],
.btn-danger {
color: var(--color-white);
background: var(--danger);
}
.input {
width: 100%;
min-height: 38px;
padding: 0 12px;
color: var(--text);
background: var(--surface);
border: var(--border);
border-radius: var(--radius-sm);
outline: none;
}
.input:focus {
border-color: var(--accent);
box-shadow: 0 0 0 3px rgba(217, 119, 87, 0.16);
}
.avatar {
display: inline-flex;
align-items: center;
justify-content: center;
width: var(--avatar-size, 38px);
height: var(--avatar-size, 38px);
border-radius: 50%;
color: var(--text-soft);
background: var(--surface-warm);
font-family: var(--font-mono);
font-size: var(--text-sm);
font-weight: 700;
letter-spacing: 0.02em;
flex: 0 0 auto;
}
.code-block {
margin: 0;
padding: var(--space-4) var(--space-5);
overflow-x: auto;
color: #E8E6DC;
background: var(--color-slate);
border-radius: var(--radius-md);
font-family: var(--font-mono);
font-size: var(--text-sm);
line-height: var(--leading-loose);
}
.code-block[data-kind="command"],
.code-block[data-wrap="true"],
.command-block {
max-width: 100%;
min-width: 0;
box-sizing: border-box;
white-space: pre-wrap;
overflow-wrap: anywhere;
word-break: break-word;
overflow-x: hidden;
}
.code-block[data-wrap="true"] code,
.code-block[data-kind="command"] code {
display: block;
max-width: 100%;
white-space: pre-wrap;
overflow-wrap: anywhere;
word-break: break-word;
}
.copyable {
position: relative;
}
.copyable > .code-block {
padding-inline-end: 88px;
}
.copy-button {
appearance: none;
position: absolute;
inset-block-start: var(--space-2);
inset-inline-end: var(--space-2);
display: inline-flex;
align-items: center;
justify-content: center;
min-height: 26px;
padding: 0 9px;
border: 1px solid rgba(250, 249, 245, 0.18);
border-radius: var(--radius-sm);
color: var(--color-gray-100);
background: rgba(255, 255, 255, 0.08);
font-family: var(--font-mono);
font-size: var(--text-xs);
font-weight: 700;
letter-spacing: 0.04em;
text-transform: uppercase;
transition:
background-color var(--dur-fast) var(--ease),
border-color var(--dur-fast) var(--ease),
transform var(--dur-fast) var(--ease);
}
.copy-button:hover {
transform: translateY(-1px);
border-color: rgba(250, 249, 245, 0.35);
background: rgba(255, 255, 255, 0.14);
}
.copy-button[data-copied="true"] {
color: var(--color-white);
background: rgba(120, 140, 93, 0.55);
border-color: rgba(120, 140, 93, 0.75);
}
.reference-panel {
--panel-pad: var(--space-5);
}
.callout {
padding: var(--space-5);
color: var(--text-soft);
background: var(--surface-tint);
border: var(--border);
border-inline-start: 4px solid var(--accent);
border-radius: var(--radius-md);
}
.callout[data-tone="success"] {
border-inline-start-color: var(--success);
background: rgba(120, 140, 93, 0.10);
}
.callout[data-tone="warning"] {
border-inline-start-color: var(--warning);
background: rgba(199, 142, 63, 0.11);
}
.callout[data-tone="danger"] {
border-inline-start-color: var(--danger);
background: rgba(176, 74, 63, 0.10);
}
.callout[data-tone="info"] {
border-inline-start-color: var(--info);
background: rgba(106, 140, 175, 0.11);
}
.callout-label {
display: block;
margin-bottom: var(--space-2);
color: var(--text-muted);
font-family: var(--font-mono);
font-size: var(--text-xs);
font-weight: 700;
letter-spacing: 0.09em;
text-transform: uppercase;
}
.callout > :last-child {
margin-bottom: 0;
}
.checklist {
list-style: none;
margin: 0;
padding: 0;
display: grid;
gap: var(--space-3);
}
.checklist li {
display: block !important;
position: relative !important;
min-width: 0;
padding-inline-start: calc(18px + var(--space-3));
overflow-wrap: anywhere;
}
.checklist li::before {
content: "✓";
position: absolute !important;
inset-block-start: 2px;
inset-inline-start: 0;
display: inline-flex;
align-items: center;
justify-content: center;
width: 18px;
height: 18px;
border-radius: 50%;
color: var(--success);
background: rgba(120, 140, 93, 0.12);
font-family: var(--font-mono);
font-size: 12px;
font-weight: 700;
line-height: 1;
}
.checklist code {
white-space: normal;
overflow-wrap: anywhere;
word-break: break-word;
}
.plain-list {
margin: 0;
padding-inline-start: 1.15em;
color: var(--text-soft);
}
.plain-list li {
overflow-wrap: anywhere;
}
.plain-list li + li {
margin-top: var(--space-2);
}
.plain-list li::marker {
color: var(--text-muted);
}
.insight-list,
.takeaway-list {
list-style: none;
margin: 0;
padding: 0;
display: grid;
gap: var(--space-3);
}
.insight-list li,
.takeaway-list li {
position: relative;
display: block;
padding-inline-start: calc(10px + var(--space-3));
color: var(--text-soft);
}
.insight-list li::before,
.takeaway-list li::before {
content: "";
position: absolute;
inset-block-start: 0.65em;
inset-inline-start: 0;
width: 7px;
height: 7px;
border-radius: 50%;
background: var(--accent);
}
.insight-list li > *,
.takeaway-list li > * {
min-width: 0;
}
.insight-list[data-tone="success"] li::before,
.takeaway-list[data-tone="success"] li::before {
background: var(--success);
}
.insight-list[data-tone="info"] li::before,
.takeaway-list[data-tone="info"] li::before {
background: var(--info);
}
.metric-list {
--metric-label: 132px;
--metric-value: 64px;
display: grid;
gap: var(--space-3);
}
.metric-row {
display: grid;
grid-template-columns: var(--metric-label) minmax(120px, 1fr) var(--metric-value);
gap: var(--space-3);
align-items: center;
}
.metric-row > :first-child {
min-width: 0;
}
.metric-row > :last-child {
justify-self: end;
font-family: var(--font-mono);
font-size: var(--text-sm);
}
.meter {
height: 9px;
overflow: hidden;
border-radius: var(--radius-pill);
background: var(--surface-tint);
}
.meter span {
display: block;
width: var(--value);
height: 100%;
background: var(--tone, var(--accent));
}
.flow-list {
list-style: none;
margin: 0;
padding: 0;
display: grid;
gap: var(--space-3);
}
.flow-step {
position: relative;
display: grid;
grid-template-columns: 42px minmax(0, 1fr);
gap: var(--space-3);
align-items: start;
padding: var(--space-4);
background: var(--surface);
border: var(--border);
border-radius: var(--radius-md);
}
.flow-step > .flow-num {
grid-column: 1;
}
.flow-step > :not(.flow-num) {
grid-column: 2;
min-width: 0;
}
.flow-step::after {
content: "";
position: absolute;
inset-block-start: calc(100% + 1px);
inset-inline-start: 36px;
width: 1.5px;
height: var(--space-3);
background: var(--border-color);
}
.flow-step:last-child::after {
display: none;
}
.flow-num {
display: inline-flex;
align-items: center;
justify-content: center;
width: 34px;
height: 34px;
border-radius: var(--radius-pill);
color: var(--text);
background: var(--surface-warm);
box-shadow: inset 0 0 0 1px rgba(20, 20, 19, 0.10);
font-family: var(--font-mono);
font-size: var(--text-sm);
font-weight: 700;
}
.flow-title {
margin: 0 0 var(--space-1);
font-family: var(--font-serif);
font-size: var(--text-xl);
font-weight: 550;
line-height: var(--leading-title);
}
.flow-detail {
margin: 0;
color: var(--text-soft);
}
.flow-branch {
display: grid;
grid-template-columns: repeat(2, minmax(0, 1fr));
gap: var(--space-3);
}
.flow-branch .flow-step::after {
display: none;
}
.flow-step[data-tone="success"] {
border-color: rgba(120, 140, 93, 0.38);
background: rgba(120, 140, 93, 0.08);
}
.flow-step[data-tone="warning"] {
border-color: rgba(199, 142, 63, 0.42);
background: rgba(199, 142, 63, 0.09);
}
@media (max-width: 620px) {
.metric-row {
grid-template-columns: 1fr max-content;
}
.metric-row .meter {
grid-column: 1 / -1;
order: 3;
}
.flow-branch {
grid-template-columns: 1fr;
}
}
/* ---------- Charts and numeric data ---------- */
.chart-panel {
max-width: 100%;
min-width: 0;
overflow: hidden;
}
.chart-panel > * {
min-width: 0;
}
.chart-panel svg,
svg.chart-svg {
display: block;
width: 100%;
height: auto;
}
.chart-caption {
color: var(--text-muted);
font-size: var(--text-sm);
}
.numeric-table-wrap {
overflow-x: auto;
background: var(--surface);
border: var(--border);
border-radius: var(--radius-md);
}
.numeric-table {
width: 100%;
min-width: 720px;
border-collapse: collapse;
}
.numeric-table th,
.numeric-table td {
padding: var(--space-3) var(--space-4);
border-bottom: 1px solid var(--color-gray-200);
vertical-align: middle;
}
.numeric-table th {
color: var(--text-muted);
background: var(--surface-tint);
font-family: var(--font-mono);
font-size: var(--text-xs);
font-weight: 700;
letter-spacing: 0.08em;
text-align: left;
text-transform: uppercase;
}
.numeric-table tr:last-child td {
border-bottom: 0;
}
.numeric-table .metric,
.numeric-table .num {
text-align: right;
font-variant-numeric: tabular-nums;
white-space: nowrap;
}
.numeric-table .entity,
.numeric-table .label-cell {
font-weight: 650;
}
.numeric-table .note {
color: var(--text-soft);
}
.numeric-table code {
white-space: normal;
overflow-wrap: anywhere;
word-break: break-word;
}
.numeric-table .subtle {
display: block;
margin-top: 2px;
color: var(--text-muted);
font-family: var(--font-mono);
font-size: var(--text-xs);
font-weight: 400;
}
@media (max-width: 620px) {
.numeric-table {
min-width: 0;
}
.numeric-table thead {
display: none;
}
.numeric-table tbody,
.numeric-table tr,
.numeric-table td {
display: block;
}
.numeric-table tr {
padding: var(--space-3) var(--space-4);
border-bottom: 1px solid var(--color-gray-200);
}
.numeric-table tr:last-child {
border-bottom: 0;
}
.numeric-table td {
padding: var(--space-1) 0;
border-bottom: 0;
}
.numeric-table td[data-label] {
display: flex;
justify-content: space-between;
gap: var(--space-4);
}
.numeric-table td[data-label]::before {
content: attr(data-label);
color: var(--text-muted);
font-family: var(--font-mono);
font-size: var(--text-xs);
text-transform: uppercase;
}
}
/* ---------- Diff ---------- */
.diff {
overflow-x: auto;
color: #E8E6DC;
background: var(--color-slate);
border-radius: var(--radius-md);
font-family: var(--font-mono);
font-size: 12.5px;
line-height: var(--leading-loose);
}
.diff-row {
display: grid;
grid-template-columns: 48px 18px minmax(max-content, 1fr);
align-items: baseline;
min-width: max-content;
padding-inline-end: var(--space-4);
white-space: pre;
}
.diff-row .ln {
padding-inline-end: 14px;
color: var(--color-gray-500);
text-align: right;
user-select: none;
}
.diff-row .mark {
color: var(--color-gray-500);
text-align: center;
}
.diff-row .code {
color: #E8E6DC;
}
.diff-row.ctx .code,
.diff-row[data-kind="ctx"] .code {
color: #B8B6AC;
}
.diff-row.add,
.diff-row[data-kind="add"] {
background: rgba(120, 140, 93, 0.24);
box-shadow: inset 3px 0 0 rgba(120, 140, 93, 0.78);
}
.diff-row.add .mark,
.diff-row[data-kind="add"] .mark {
color: #B9D394;
font-weight: 800;
}
.diff-row.del,
.diff-row[data-kind="del"] {
background: rgba(176, 74, 63, 0.24);
box-shadow: inset 3px 0 0 rgba(176, 74, 63, 0.82);
}
.diff-row.del .mark,
.diff-row[data-kind="del"] .mark {
color: #F19A8D;
font-weight: 800;
}
.diff-row.hunk,
.diff-row[data-kind="hunk"] {
background: rgba(255, 255, 255, 0.045);
}
.diff-row.hunk .code,
.diff-row[data-kind="hunk"] .code {
color: var(--color-gray-500);
}
.diff[data-wrap="true"] {
overflow-x: hidden;
}
.diff[data-wrap="true"] .diff-row {
grid-template-columns: 42px 18px minmax(0, 1fr);
min-width: 0;
white-space: normal;
}
.diff[data-wrap="true"] .code {
white-space: pre-wrap;
overflow-wrap: anywhere;
}
/* ---------- Timeline ---------- */
.timeline {
position: relative;
display: grid;
gap: 0;
padding-inline-start: var(--space-6);
}
.timeline:is(ol, ul) {
margin: 0;
list-style: none;
}
.timeline::before {
content: "";
position: absolute;
inset-block: 4px 4px;
inset-inline-start: 9px;
width: 1.5px;
background: var(--border-color);
}
.timeline-item,
.tl-entry {
position: relative;
display: grid;
grid-template-columns: minmax(84px, max-content) minmax(0, 1fr);
gap: var(--space-4);
padding-block: 0 var(--space-5);
}
.timeline-item:last-child,
.tl-entry:last-child {
padding-block-end: 0;
}
.timeline-item::before,
.tl-entry::before {
content: "";
position: absolute;
inset-block-start: 4px;
inset-inline-start: calc(4.25px - var(--space-6));
width: 11px;
height: 11px;
border: 2px solid var(--surface);
border-radius: 50%;
background: var(--accent);
box-shadow: 0 0 0 1.5px var(--accent);
}
.timeline-item:not(:has(> .timeline-time, > .tl-time)),
.tl-entry:not(:has(> .timeline-time, > .tl-time)) {
display: block;
}
.timeline-time,
.tl-time {
color: var(--text-muted);
font-family: var(--font-mono);
font-size: var(--text-sm);
white-space: nowrap;
}
.timeline-body,
.tl-body {
min-width: 0;
color: var(--text-soft);
}
.timeline-body strong,
.tl-body strong {
color: var(--text);
}
@media (max-width: 620px) {
.timeline-item,
.tl-entry {
grid-template-columns: 1fr;
gap: var(--space-1);
}
}
/* ---------- Flowchart ---------- */
.flowchart {
display: block;
width: 100%;
height: auto;
}
svg.flow,
svg.flowchart {
display: block;
width: 100%;
height: auto;
}
.flow text,
.flowchart text {
fill: var(--text);
font-family: var(--font-sans);
font-size: 12px;
}
.flow .sub,
.flowchart .sub {
fill: var(--text-muted);
font-size: 10px;
}
.flow-edge,
.edge {
fill: none;
stroke: var(--text-muted);
stroke-width: 1.5;
}
.flow-edge[data-kind="yes"],
.edge.yes {
stroke: var(--success);
}
.flow-edge[data-kind="no"],
.edge.no {
stroke: var(--danger);
stroke-dasharray: 4 4;
}
/* SVG flow nodes */
.flow-node,
.flow .node {
cursor: pointer;
transition: transform var(--dur-fast) var(--ease);
}
.flow-node:hover,
.flow .node:hover {
transform: translateY(-1px);
}
.flow-node rect,
.flow .node rect {
fill: var(--surface);
stroke: var(--border-color);
stroke-width: 1.5;
rx: 8;
}
.flow-node path,
.flow .node.gate path {
fill: var(--surface);
stroke: var(--border-color);
stroke-width: 1.5;
}
.flow-node[data-shape="term"] rect,
.flow .node.term rect {
fill: var(--surface-tint);
rx: 22;
}
.flow-node[data-kind="ok"] rect,
.flow .node.ok rect {
fill: rgba(120, 140, 93, 0.12);
stroke: var(--success);
}
.flow-node[data-kind="bad"] rect,
.flow .node.bad rect {
fill: rgba(176, 74, 63, 0.10);
stroke: var(--danger);
}
.flow-node.active rect,
.flow-node.active path,
.flow .node.active rect,
.flow .node.active path {
stroke: var(--accent);
stroke-width: 2;
}
/* HTML flow nodes, for non-SVG diagrams */
div.flow-node {
padding: var(--space-3) var(--space-4);
background: var(--surface);
border: var(--border);
border-radius: var(--radius-sm);
transition:
transform var(--dur-fast) var(--ease),
border-color var(--dur-fast) var(--ease),
box-shadow var(--dur-fast) var(--ease);
}
div.flow-node:hover {
transform: translateY(var(--hover-y));
border-color: rgba(217, 119, 87, 0.55);
box-shadow: var(--shadow-sm);
}
div.flow-node[data-shape="term"] {
border-radius: var(--radius-pill);
background: var(--surface-tint);
}
div.flow-node[data-kind="ok"] {
border-color: var(--success);
background: rgba(120, 140, 93, 0.12);
}
div.flow-node[data-kind="bad"] {
border-color: var(--danger);
background: rgba(176, 74, 63, 0.10);
}
@media (prefers-reduced-motion: reduce) {
*,
*::before,
*::after {
scroll-behavior: auto !important;
transition-duration: 0.01ms !important;
animation-duration: 0.01ms !important;
animation-iteration-count: 1 !important;
}
}
/* Responsive safety net for generated artifacts. */
p,
li {
overflow-wrap: anywhere;
}
@media (max-width: 860px) {
.split,
.section-rail,
.sidebar-layout {
grid-template-columns: minmax(0, 1fr) !important;
}
.split > *,
.section-rail > *,
.sidebar-layout > *,
.chart-panel {
width: 100%;
max-width: 100%;
min-width: 0;
}
}</style>
<style>
.flow-svg { width: 100%; height: auto; max-width: 720px; }
.flow-svg text { font-family: inherit; font-size: 11px; fill: var(--text-muted); }
.flow-svg .node-num { font-size: 13px; font-weight: 600; fill: var(--surface); }
.flow-svg .node-label { font-size: 11px; fill: var(--text); }
.numeric-table code,
.numeric-table .note { white-space: normal; overflow-wrap: anywhere; word-break: break-word; }
</style>
</head>
<body>
<main class="page stack" data-gap="lg">
<header class="stack" data-gap="sm">
<div class="eyebrow">Module explainer</div>
<h1>How the Birch rendering checker turns HTML into a report.</h1>
<p class="lede">A new-contributor map of <code>scripts/check_birch_renderings.py</code>: the static parsers, the optional headless-Chrome geometry audit, and the JSON/Markdown/PNG outputs you must keep stable when you modify a rendering eval.</p>
<div class="cluster">
<span class="chip" data-tone="olive">Static + visual smoke</span>
<span class="chip">Two CLI modes</span>
<span class="chip" data-tone="info">Deterministic-first</span>
</div>
</header>
<!-- 1. Mental model -->
<section class="section stack" data-gap="lg">
<div class="section-head">
<div>
<span class="eyebrow">1. Mental model</span>
<h2>One pipeline, two input shapes, one report.</h2>
</div>
</div>
<div class="auto-grid" style="--grid-min: 240px">
<article class="card stack" data-variant="outlined" data-gap="sm">
<span class="caption">Input</span>
<h3>Pairs or artifacts</h3>
<p>Either <code>--pair reference:candidate</code> or repeated <code>--artifact path</code>. The two modes are mutually exclusive; mixing them raises <code>SystemExit("use either --artifact or --pair, not both")</code>.</p>
</article>
<article class="card stack" data-variant="outlined" data-gap="sm">
<span class="caption">Engine</span>
<h3>Parse, then optionally render</h3>
<p>An <code>html.parser.HTMLParser</code> stack extracts tags, classes, CSS vars and structural contracts. If a Chrome binary is on <code>PATH</code>, the same HTML is rendered headless and a JS audit is injected to measure geometry.</p>
</article>
<article class="card stack" data-variant="outlined" data-gap="sm">
<span class="caption">Output</span>
<h3>Findings, not opinions</h3>
<p>Every check produces a <code>Finding(level, name, evidence)</code>. Levels are <code>pass</code>, <code>warn</code>, <code>fail</code>, <code>note</code>. The process exits non-zero on any <code>fail</code> (or any <code>warn</code> under <code>--fail-on-warn</code>).</p>
</article>
</div>
<aside class="callout stack" data-tone="info" data-gap="xs">
<span class="callout-label">Key distinction</span>
<p><strong>Artifact mode is candidate-only.</strong> The module docstring states it explicitly: artifact mode "does not self-compare screenshots; it captures rendered evidence and flags egregious visible breakage that static parsing cannot see." True <code>--pair</code> mode is for the small <code>DEFAULT_PAIRS</code> set in <code>scripts/check_birch_renderings.py</code>.</p>
</aside>
</section>
<!-- 2. Runtime path -->
<section class="section stack" data-gap="lg">
<div class="section-head">
<div>
<span class="eyebrow">2. Runtime path</span>
<h2>From an HTML file to <code>reports/birch-rendering-check.{json,md}</code>.</h2>
</div>
</div>
<div class="panel chart-panel stack" data-gap="sm">
<svg class="flow-svg chart-svg" viewBox="0 0 720 170" role="img" aria-label="Six-stage flow: parse HTML, run contract parsers, optional Chrome render, optional Pillow palette metrics, geometry audit, write JSON and Markdown report.">
<title>Rendering checker runtime path</title>
<desc>Numbered nodes 1 through 6 connected left-to-right. Nodes 3, 4 and 5 sit on the optional headless-Chrome branch. The full ordered list follows the diagram.</desc>
<!-- connectors -->
<line x1="80" y1="70" x2="170" y2="70" stroke="var(--border-color)" stroke-width="1.5" fill="none"/>
<line x1="230" y1="70" x2="320" y2="70" stroke="var(--border-color)" stroke-width="1.5" fill="none"/>
<line x1="380" y1="70" x2="470" y2="70" stroke="var(--border-color)" stroke-width="1.5" fill="none"/>
<line x1="530" y1="70" x2="620" y2="70" stroke="var(--border-color)" stroke-width="1.5" fill="none"/>
<!-- branch from node 3 down to optional render lane (visual annotation) -->
<line x1="350" y1="100" x2="350" y2="130" stroke="var(--border-color)" stroke-width="1" stroke-dasharray="3 3" fill="none"/>
<!-- node 1: parse -->
<circle cx="50" cy="70" r="22" fill="var(--accent)" stroke="none"/>
<text class="node-num" x="50" y="74" text-anchor="middle">1</text>
<text class="node-label" x="50" y="118" text-anchor="middle">page_stats</text>
<!-- node 2: contract -->
<circle cx="200" cy="70" r="22" fill="var(--accent)" stroke="none"/>
<text class="node-num" x="200" y="74" text-anchor="middle">2</text>
<text class="node-label" x="200" y="118" text-anchor="middle">contract_findings</text>
<!-- node 3: optional capture -->
<circle cx="350" cy="70" r="22" fill="var(--olive, #788C5D)" stroke="none"/>
<text class="node-num" x="350" y="74" text-anchor="middle">3</text>
<text class="node-label" x="350" y="118" text-anchor="middle">Chrome capture</text>
<text x="350" y="148" text-anchor="middle" font-style="italic">optional</text>
<!-- node 4: pillow metrics -->
<circle cx="500" cy="70" r="22" fill="var(--olive, #788C5D)" stroke="none"/>
<text class="node-num" x="500" y="74" text-anchor="middle">4</text>
<text class="node-label" x="500" y="118" text-anchor="middle">palette / blackish</text>
<!-- node 5: geometry -->
<circle cx="650" cy="70" r="22" fill="var(--olive, #788C5D)" stroke="none"/>
<text class="node-num" x="650" y="74" text-anchor="middle">5</text>
<text class="node-label" x="650" y="118" text-anchor="middle">geometry_audit</text>
</svg>
<p class="chart-caption">Nodes correspond to functions in <code>scripts/check_birch_renderings.py</code>. The clay nodes (1–2) always run; the olive nodes (3–5) only run when <code>find_chrome()</code> finds a Chromium/Chrome binary. A final write step (node 6 below) always runs.</p>
</div>
<ol class="flow-list">
<li class="flow-step">
<span class="flow-num">1</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">Parse HTML into <code>PageStats</code></h3>
<p class="flow-detail"><code>page_stats(path)</code> reads the file, locates the <code>&lt;style data-birch-system&gt;</code> block, runs <code>StatsParser</code> (tag/class/data-attr counts, inline styles, stylesheet links, text words), and collects defined/used CSS variables.</p>
</div>
</li>
<li class="flow-step">
<span class="flow-num">2</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">Run static contract parsers</h3>
<p class="flow-detail"><code>contract_findings()</code> runs seven structural parsers — <code>GridListParser</code>, <code>ChecklistParser</code>, <code>MetricRowParser</code>, <code>DiffRowParser</code>, <code>DiffPolarityParser</code>, <code>FlowStepParser</code>, <code>TimelineParser</code> — plus <code>svg_visual_findings()</code> for <code>fill</code>/<code>stroke</code> defaults.</p>
</div>
</li>
<li class="flow-step">
<span class="flow-num">3</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">Capture a headless screenshot (optional)</h3>
<p class="flow-detail">If <code>find_chrome()</code> returns a binary, <code>capture()</code> invokes <code>--headless=new --screenshot</code>. For <code>deep:*</code> viewports, <code>measure_document_height()</code> first injects a temp HTML in the same directory to read <code>scrollHeight</code>.</p>
</div>
</li>
<li class="flow-step">
<span class="flow-num">4</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">Compute Pillow palette/blackish metrics</h3>
<p class="flow-detail"><code>artifact_screenshot_metrics()</code> (or <code>screenshot_metrics()</code> in pair mode) downsamples the PNG, then compares pixels against the <code>PALETTE</code> dict to flag <code>palette_drift</code>, <code>blank_render</code>, or <code>black_pixel_fraction</code>.</p>
</div>
</li>
<li class="flow-step">
<span class="flow-num">5</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">Inject the JS geometry audit</h3>
<p class="flow-detail"><code>geometry_audit()</code> writes the HTML to a temp directory with a <code>&lt;base&gt;</code> tag plus a window-load script. Chrome dumps the DOM; the audit reads <code>data-birch-audit</code> JSON and turns it into overflow, squeeze, metric-alignment, and code-wrap findings.</p>
</div>
</li>
<li class="flow-step" data-tone="success">
<span class="flow-num">6</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">Write JSON + Markdown, exit code</h3>
<p class="flow-detail"><code>main()</code> writes <code>--out</code> (default <code>reports/birch-rendering-check.json</code>) and <code>--markdown</code> via <code>render_markdown()</code>. Process exits <code>1</code> when <code>summary.failures &gt; 0</code> or <code>summary.warnings &gt; 0</code> under <code>--fail-on-warn</code>.</p>
</div>
</li>
</ol>
</section>
<!-- 3. File tour -->
<section class="section stack" data-gap="lg">
<div class="section-head">
<div>
<span class="eyebrow">3. File tour</span>
<h2>Read these six files in this order.</h2>
</div>
</div>
<ol class="flow-list">
<li class="flow-step">
<span class="flow-num">1</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">scripts/check_birch_renderings.py</h3>
<p class="flow-detail">Start at <code>main()</code><code>check_artifact()</code> / <code>compare_pair()</code><code>page_stats()</code><code>contract_findings()</code> → the seven <code>*Parser</code> classes → <code>geometry_audit()</code><code>render_markdown()</code>. The module docstring at the top is the cleanest single-paragraph mental model.</p>
</div>
</li>
<li class="flow-step">
<span class="flow-num">2</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">styles/birch-system.css</h3>
<p class="flow-detail">The 1673-line source of truth for tokens, classes, and grid contracts (<code>.flow-step</code>, <code>.metric-row</code>, <code>.diff-row</code>, <code>.timeline-item</code>). <code>css_defined_vars()</code> reads this file to populate <code>system_defined_vars</code>, which drives <code>no_unknown_css_vars</code>.</p>
</div>
</li>
<li class="flow-step">
<span class="flow-num">3</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">docs/birch-llm-style-guide.md</h3>
<p class="flow-detail">Recipe routing and the primitive index. The "Quick primitive index" and the strict-component descriptions match the checker's parsers one-for-one; treat it as the user-facing spec the checker enforces.</p>
</div>
</li>
<li class="flow-step">
<span class="flow-num">4</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">evals/charts/build_chart_brief.py</h3>
<p class="flow-detail">A worked example of producing an artifact the checker is happy with: composes <code>.chart-panel</code>, <code>.numeric-table</code>, <code>.metric-row</code>, and a Matplotlib SVG. Useful as a regression fixture when you modify a parser.</p>
</div>
</li>
<li class="flow-step">
<span class="flow-num">5</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">scripts/birch_mpl.py</h3>
<p class="flow-detail">Defines the <code>COLORS</code> and <code>PALETTE</code> the checker's Pillow stage tries to match (<code>palette_close_fraction</code>). <code>svg_string()</code> strips Matplotlib metadata; if you change the SVG postprocessing here, expect <code>svg_chart_mark_presentation</code> in the checker to react.</p>
</div>
</li>
<li class="flow-step">
<span class="flow-num">6</span>
<div class="stack" data-gap="xs">
<h3 class="flow-title">evals/charts/run_eval.py</h3>
<p class="flow-detail">The minimal end-to-end driver. It calls the builder, then runs the checker at four viewports (<code>desktop</code>, <code>mobile</code>, <code>deep</code>, <code>mobile-deep</code>). Copy this shape when adding a new eval; the checker has no opinion on builders, only on outputs.</p>
</div>
</li>
</ol>
</section>
<!-- 4. Gotchas -->
<section class="section stack" data-gap="lg">
<div class="section-head">
<div>
<span class="eyebrow">4. Gotchas</span>
<h2>Quiet ways to break an existing eval.</h2>
</div>
</div>
<ul class="insight-list">
<li><span><strong>Birch CSS minimum bytes.</strong> The <code>uses_birch_system_css</code> check requires both <code>BIRCH_CSS_MIN_BYTES = 10_000</code> bytes inside <code>&lt;style data-birch-system&gt;</code> <em>and</em> every signature in <code>BIRCH_CSS_SIGNATURES</code>. Truncating the placeholder for token savings is a silent failure.</span></li>
<li><span><strong>Any line starting with <code>+</code> fails.</strong> <code>no_patch_markers</code> checks <code>html.splitlines()</code>; even a leading <code>+</code> in an unindented prose line will flip the check. Wrap diff polarity in <code>&lt;span class="mark"&gt;</code>.</span></li>
<li><span><strong>Diff polarity is independent of the marker.</strong> A <code>.diff-row</code> with mark <code>+</code> must also carry <code>.add</code> or <code>data-kind="add"</code>; otherwise <code>diff_row_polarity</code> flags it. Same for <code>-</code> / <code>.del</code>.</span></li>
<li><span><strong>Strict-children parsers count loose text.</strong> <code>FlowStepParser</code>, <code>DiffRowParser</code>, and <code>MetricRowParser</code> walk direct children at <code>depth == 1</code>. Whitespace text nodes are fine, but a stray <code>&lt;p&gt;</code> beside <code>.flow-num</code> will fail <code>flow_step_contract</code>.</span></li>
<li><span><strong>Geometry audit needs a working <code>&lt;base&gt;</code>.</strong> <code>geometry_audit()</code> copies the HTML to a temp dir and prepends <code>&lt;base href="file://.../"&gt;</code> so <code>styles/birch-system.css</code> resolves. If you pre-injected your own <code>&lt;base&gt;</code>, the relative stylesheet link may break and the audit will silently run against unstyled HTML.</span></li>
<li><span><strong>SVG chart marks default to black fill.</strong> Any <code>&lt;polyline&gt;</code> or chart-class <code>&lt;path&gt;</code> without <code>fill="none"</code> and an explicit <code>stroke</code> raises <code>svg_chart_mark_presentation</code>. Hand-written charts are the usual offenders.</span></li>
<li><span><strong>Local CSS budget is loose but watched.</strong> Over <code>2500</code> bytes of page-local CSS produces a warning (<code>local_css_size</code>); gradients in local CSS produce a hard failure (<code>no_birch_gradients</code>).</span></li>
<li><span><strong>Deep viewports rewrite themselves.</strong> <code>measure_document_height()</code> writes <code>.{stem}-measure-*.html</code> next to your artifact for the height probe. If the artifact directory is read-only, deep capture quietly falls back to the requested window height.</span></li>
</ul>
</section>
<!-- 5. Extension points -->
<section class="section stack" data-gap="lg">
<div class="section-head">
<div>
<span class="eyebrow">5. Extension points</span>
<h2>Where to plug new behavior in.</h2>
</div>
</div>
<div class="auto-grid" style="--grid-min: 260px">
<article class="card stack" data-variant="outlined" data-gap="sm">
<span class="caption">Add a structural contract</span>
<h3>New <code>HTMLParser</code> subclass</h3>
<p>Model it on <code>MetricRowParser</code>: track <code>in_*</code> + <code>depth</code>, capture direct children at <code>depth == 1</code>, append to a <code>bad_*</code> list, then feed and consume in <code>contract_findings()</code>.</p>
</article>
<article class="card stack" data-variant="outlined" data-gap="sm">
<span class="caption">Add a class to the vocabulary</span>
<h3><code>BIRCH_CLASSES</code> / <code>LAYOUT_CLASSES</code> / <code>SEMANTIC_CLASSES</code></h3>
<p>Three sets at the top of the module. Adding a class to <code>SEMANTIC_CLASSES</code> changes the <code>uses_semantic_components</code> warning threshold (currently <code>SEMANTIC_CLASS_MIN = 6</code>).</p>
</article>
<article class="card stack" data-variant="outlined" data-gap="sm">
<span class="caption">Add a geometry check</span>
<h3>JS branch in <code>geometry_audit()</code></h3>
<p>Extend the embedded <code>&lt;script&gt;</code> to push a new array onto <code>data-birch-audit</code>, then add a matching branch in <code>geometry_findings()</code>. Mirror the pass/fail symmetry of <code>layout_overflow</code>.</p>
</article>
<article class="card stack" data-variant="outlined" data-gap="sm">
<span class="caption">Add a palette tone</span>
<h3><code>PALETTE</code> dict</h3>
<p>Adds the colour to the Pillow palette-close comparison and the <code>is_palette_hex()</code> tolerance check. Keep the tuple aligned with <code>scripts/birch_mpl.py:COLORS</code>.</p>
</article>
<article class="card stack" data-variant="outlined" data-gap="sm">
<span class="caption">Add a viewport profile</span>
<h3><code>VIEWPORTS</code> in <code>evals/charts/run_eval.py</code></h3>
<p>The checker accepts any <code>name:WIDTHxHEIGHT</code> via <code>--viewport</code>. Names containing <code>deep</code> activate <code>measure_document_height()</code>; everything else uses the literal height.</p>
</article>
<article class="card stack" data-variant="outlined" data-gap="sm">
<span class="caption">Tune a threshold</span>
<h3>Module-level constants</h3>
<p><code>BIRCH_CSS_MIN_BYTES</code>, <code>SEMANTIC_CLASS_MIN</code>, the <code>0.55</code> palette floor in <code>screenshot_findings()</code>, and the <code>2500</code>-byte local-CSS warning all live as named constants. Change them one at a time; the eval drivers expect stable thresholds.</p>
</article>
</div>
</section>
<!-- 6. Where to change behavior (precise pointers) -->
<section class="section stack" data-gap="lg">
<div class="section-head">
<div>
<span class="eyebrow">6. Where to change behavior</span>
<h2>Precise pointers for common edits.</h2>
</div>
</div>
<div class="numeric-table-wrap">
<table class="numeric-table">
<thead>
<tr>
<th class="label-cell">If you want to change…</th>
<th>Edit here</th>
<th>Affects finding</th>
</tr>
</thead>
<tbody>
<tr>
<td class="entity">CSS vocabulary tolerated by the checker</td>
<td><code>styles/birch-system.css</code></td>
<td><code>no_unknown_css_vars</code></td>
</tr>
<tr>
<td class="entity">Default <code>--pair</code> set</td>
<td><code>DEFAULT_PAIRS</code> in <code>scripts/check_birch_renderings.py</code></td>
<td>which files run when no <code>--pair</code> is given</td>
</tr>
<tr>
<td class="entity">Required minimum Birch CSS size</td>
<td><code>BIRCH_CSS_MIN_BYTES</code></td>
<td><code>uses_birch_system_css</code></td>
</tr>
<tr>
<td class="entity">Strict child contract for a primitive</td>
<td>The matching <code>*Parser</code> class</td>
<td><code>flow_step_contract</code>, <code>metric_row_contract</code>, <code>diff_row_contract</code>, <code>timeline_item_contract</code></td>
</tr>
<tr>
<td class="entity">Palette tolerance / new tone</td>
<td><code>PALETTE</code> and <code>is_palette_hex()</code></td>
<td><code>local_literal_colors</code>, <code>palette_drift</code></td>
</tr>
<tr>
<td class="entity">Geometry threshold (overflow, squeeze, code wrap)</td>
<td>JS audit + <code>geometry_findings()</code></td>
<td><code>layout_overflow</code>, <code>code_wrap_underfill</code>, <code>pathological_text_wrapping</code></td>
</tr>
<tr>
<td class="entity">Report destination</td>
<td>CLI defaults <code>--out</code>, <code>--markdown</code>, <code>--screenshots-dir</code></td>
<td>file paths only</td>
</tr>
</tbody>
</table>
</div>
</section>
<!-- 7. Commands and outputs -->
<section class="section stack" data-gap="lg">
<div class="section-head">
<div>
<span class="eyebrow">7. Commands and outputs</span>
<h2>Run it locally; know what you wrote.</h2>
</div>
</div>
<div class="section-rail">
<div class="stack" data-gap="md">
<article class="card stack" data-variant="outlined" data-gap="sm">
<h3>Check one artifact</h3>
<pre class="code-block" data-kind="command" data-wrap="true">uv run --with pillow python scripts/check_birch_renderings.py --artifact 24-birch-chart-brief.html</pre>
<p class="muted">Writes <code>reports/birch-rendering-check.json</code> and <code>reports/birch-rendering-check.md</code>; prints both paths.</p>
</article>
<article class="card stack" data-variant="outlined" data-gap="sm">
<h3>Run the bundled eval at four viewports</h3>
<pre class="code-block" data-kind="command" data-wrap="true">uv run python evals/charts/run_eval.py</pre>
<p class="muted">Rebuilds <code>24-birch-chart-brief.html</code> via <code>build_chart_brief.py</code>, then runs the checker for <code>desktop:1365x900</code>, <code>mobile:390x900</code>, <code>deep:1365x2400</code>, and <code>mobile-deep:390x3000</code>.</p>
</article>
<article class="card stack" data-variant="outlined" data-gap="sm">
<h3>Compare a reference / candidate pair</h3>
<pre class="code-block" data-kind="command" data-wrap="true">uv run --with pillow python scripts/check_birch_renderings.py --pair 05-design-system.html:05-design-system-birch.html</pre>
<p class="muted">Adds <code>deltas</code>, an amplified diff PNG, and a three-up contact sheet to the report.</p>
</article>
</div>
<aside class="reference-panel stack" data-gap="md">
<h3>Outputs you can rely on</h3>
<ul class="plain-list">
<li><code>reports/birch-rendering-check.json</code> — full payload with <code>mode</code>, <code>artifacts</code>/<code>pairs</code>, <code>summary</code>.</li>
<li><code>reports/birch-rendering-check.md</code> — table of findings with level/check/evidence per artifact.</li>
<li><code>reports/birch-screenshots/&lt;stem&gt;-&lt;viewport&gt;.png</code> — one PNG per artifact × viewport.</li>
<li><code>reports/birch-screenshots/&lt;ref&gt;__vs__&lt;cand&gt;-diff.png</code> — pair mode only, brightness-amplified.</li>
<li><code>reports/birch-screenshots/&lt;ref&gt;__vs__&lt;cand&gt;-contact.png</code> — pair mode three-up source / candidate / diff.</li>
</ul>
<h3>Process exit</h3>
<ul class="plain-list">
<li><code>0</code> when <code>summary.failures == 0</code>.</li>
<li><code>1</code> on any <code>fail</code>, or any <code>warn</code> under <code>--fail-on-warn</code>.</li>
</ul>
</aside>
</div>
</section>
<!-- 8. Don't break this -->
<section class="section stack" data-gap="md">
<aside class="callout stack" data-tone="warning" data-gap="xs">
<span class="callout-label">Before you commit</span>
<p>Run the eval driver against an artifact you have not touched (<code>evals/charts/run_eval.py</code> is the cheapest). If <code>summary.failures</code> changes for an unrelated artifact, your parser, threshold, or audit edit has broader reach than intended — bisect by reverting one constant or one parser at a time.</p>
</aside>
</section>
</main>
</body>
</html>

Xet Storage Details

Size:
58.8 kB
·
Xet hash:
d75a761dfc6f254aa98776de232ef696fa56453db1f825d3bc5d0af90c4f4465

Xet efficiently stores files, intelligently splitting them into unique chunks and accelerating uploads and downloads. More info.