Hebrew Rtl Best Practices

Hebrew RTL Best Practices

Instructions

Step 1: Set Up Document Direction

Always start with the HTML attribute (not just CSS):

<html lang="he" dir="rtl">

This tells browsers, screen readers, and CSS to use RTL as the base direction.

Step 2: Use CSS Logical Properties

NEVER use physical directional properties for layout:

This ensures the layout automatically mirrors in RTL mode.

When you genuinely need a direction-specific rule that logical properties cannot express, prefer the :dir() pseudo-class over [dir="rtl"] attribute selectors:

/* Modern: matches the resolved direction, including dir="auto" and inheritance */
.chevron:dir(rtl) { transform: scaleX(-1); }

/* Older approach: only matches an explicit dir attribute on/above the element */
[dir="rtl"] .chevron { transform: scaleX(-1); }

:dir() is part of Selectors Level 4 and resolves the computed direction, so it also works for elements whose direction comes from dir="auto" or from an ancestor, where an attribute selector would miss them. Browser support: Chrome and Edge shipped it in version 120 (late 2023), Firefox has supported it for years, and Safari added it in 16.4, so it is now Baseline (widely available). For older-browser support, keep an [dir="rtl"] fallback rule or use a logical property instead. Check current support at https://caniuse.com/css-dir-pseudo.

Step 3: Handle Bidirectional Text

When mixing Hebrew and English/numbers:

/* Isolate embedded LTR content */
.ltr-content {
  unicode-bidi: isolate;
  direction: ltr;
}

/* Mixed or unknown-direction content: each paragraph picks its own base direction */
.user-content {
  unicode-bidi: plaintext;
}

Do not use unicode-bidi: bidi-override for mixed content. It switches off the implicit part of the bidi algorithm and lays every character out strictly in the direction value, so English inside an RTL override renders letter-reversed. Reserve it (or <bdo>) for deliberately forcing a known visual order.

Common bidi issues:

• Phone numbers written with spaces (050 321 4450) or a +972 prefix appearing scrambled: wrap in <bdo dir="ltr">. A plain hyphenated 050-321-4450 already stays intact, because a single hyphen between two numbers joins them into one number run.
• Punctuation at wrong end of sentence: Use unicode-bidi: isolate
• URLs/emails in Hebrew text: Wrap in <span dir="ltr">

Numbers and dates: Standalone numbers and DD/MM/YYYY dates inside Hebrew text usually render fine because digits are weak-LTR, but a number that is immediately followed by a sign, currency, or a second number can flip. When a value must keep a fixed visual order, isolate it with <span dir="ltr"> or unicode-bidi: isolate rather than trusting the default bidi resolution.

Format the value, then isolate it. Bidi isolation only stops a correct string from flipping; it does not produce the right string. Use Intl to format, then isolate: Intl.NumberFormat('he-IL', { style: 'currency', currency: 'ILS' }) for shekel amounts and Intl.DateTimeFormat('he-IL') for dates, and wrap the output in <bdi> (or unicode-bidi: isolate) if it sits inline in Hebrew prose. Do not force dir="ltr" on he-IL output: the currency string carries its own right-to-left marks (U+200F) and is laid out for an RTL context, so forcing LTR moves the ₪ to the other side of the number. The distinction: force dir="ltr" on raw digit strings such as phone numbers, which carry no direction marks, and only isolate Intl output, which does. Devs commonly conflate the two and apply bidi fixes to a formatting bug (or vice versa).

Hebrew dates need the calendar extension. Intl.DateTimeFormat('he-IL') resolves to the Gregorian calendar (resolvedOptions().calendar === 'gregory'), so a Hebrew locale alone will not give you a Hebrew date. Request the calendar through the -u-ca- Unicode extension: Intl.DateTimeFormat('he-IL-u-ca-hebrew') formats 20 September 2026 as 9 בתשרי 5787. Use it for holiday, yahrzeit, and dual-date displays, and keep the Gregorian format for anything users file with an authority.

Form inputs need dir="auto". Put dir="auto" on every <input> and <textarea> so each value resolves its own base direction. This is the most visible end-user RTL bug: an email or an English word typed into a Hebrew form jumps to the wrong side without it. Note that the placeholder does not trigger auto-detection, so set the resting direction with CSS if the empty-field look matters. Two exceptions. A type="tel" input is already LTR by default (the HTML spec gives a tel input without dir an LTR directionality), so leave dir off it. For email and url fields most values are Latin, so set dir="ltr" deliberately: with dir="auto" a value that starts with Hebrew, such as an address on the Hebrew-script domain .ישראל, flips the field to RTL mid-typing. Weigh that against the cost: dir="ltr" also left-aligns a Hebrew placeholder.

<bdi> vs <bdo>: use <bdo dir="ltr"> only when you want to force a direction (it overrides the bidi algorithm). For user-generated or unknown-direction content, prefer <bdi>, which isolates the content so its direction is auto-detected and cannot leak into the surrounding text:

<!-- User name could be Hebrew or Latin; bdi isolates it either way -->
<p>שלום, <bdi>{{ userName }}</bdi>, ברוך הבא</p>

Pair dir with lang on embedded runs. dir only fixes visual order. Mark an English term inside Hebrew prose as <span lang="en" dir="ltr">: speech synthesizers and Braille translators use the language tag to switch language mode, and :lang() font and hyphenation rules key on it. Without it, assistive tech has no signal to leave Hebrew mode for that run.

For free-text fields, dir="auto" (or unicode-bidi: plaintext in CSS) lets the browser pick the base direction per value, which is the correct default for comments, names, and search queries where you do not know the language in advance.

Shadows and gradients do not auto-flip. CSS logical properties mirror layout, but box-shadow, text-shadow, and linear-gradient offsets/angles are physical and stay fixed when direction flips. A shadow offset of 4px 4px that looks correct in LTR will point the "wrong" way relative to an RTL layout. The same physical-not-logical trap applies to transform-origin, background-position, and translateX-based keyframe animations (slide-in drawers, carousels, progress shimmer). Flip each explicitly with a :dir(rtl) (or [dir="rtl"]) override when its direction is meaningful.

Step 4: Mirror Directional Icons

Icon mirroring is one of the highest-frequency RTL bugs. The rule: mirror icons whose meaning is tied to reading direction, leave everything else alone.

Mirror these (their direction encodes "forward/back/next/previous" relative to reading order):

• Navigation arrows, back/forward buttons, breadcrumb chevrons
• "Send" / submit arrows, carousel and pagination arrows
• Indentation, list-nesting, and reply arrows
• Progress indicators that imply forward motion

Do NOT mirror these (mirroring makes them wrong or unrecognizable):

• Logos and brand marks
• Checkmarks and X / close icons
• Media play buttons (a play button always points right, it refers to the timeline, not reading direction)
• Clocks and analog-time icons (clockwise is universal)
• Icons depicting real-world objects with a fixed orientation (a phone handset, a magnifying glass with the handle, most product icons)

Technique, mirror with a horizontal flip transform:

/* Flip only when the document direction is RTL */
.icon-directional:dir(rtl) { transform: scaleX(-1); }

<!-- Tailwind: rtl: variant for the cases logical properties cannot cover -->
<button class="rtl:-scale-x-100">
  <ArrowLeftIcon />
</button>

Many icon sets (for example Material Symbols) already ship RTL-aware variants, prefer those over flipping when available, because a flipped icon can mis-render fine detail or embedded text.

Step 5: Hebrew Typography

Recommended font stack:

font-family: 'Heebo', 'Assistant', 'Rubik', 'Noto Sans Hebrew', sans-serif;

Typography settings:

html[dir="rtl"] body {
  line-height: 1.7;
  letter-spacing: normal; /* no tracking on running text */
}

Letter-spacing is a Hebrew emphasis device, so do not ban it globally. Keep running text at letter-spacing: normal, but Hebrew typography deliberately uses letter-spacing (tracking) to emphasise names, terms, and concepts. A blanket letter-spacing: 0 !important reset in an RTL theme strips that legitimate emphasis.

Hebrew has no letter case. The widely used modern scripts with case are Latin, Greek, Armenian, and Cyrillic, Hebrew is not among them, so text-transform: uppercase / capitalize and font-variant: small-caps are no-ops on Hebrew letters. They are not no-ops on the Latin words embedded in the same element: a shared design-system button or heading that uppercases its label leaves the Hebrew untouched while shouting "GMAIL" or "PDF" beside it. Remove case transforms from the RTL theme rather than assuming they do nothing.

Nikkud and cantillation marks need vertical room. Vowel points are combining marks that sit below or above the base letter and enlarge the effective glyph box. A tight line-height (1.2 or less) clips them or collides them with the line above, which is the practical reason for the 1.7 recommended here. Some Latin-first webfonts also ship Hebrew letters without the nikkud glyphs, so test any pointed text (liturgy, children's content, dictionaries) in the actual font before shipping.

Step 6: Framework-Specific Setup

Tailwind CSS RTL (v4, current; logical utilities since v3.3):

Prefer logical property utilities over rtl:/ltr: variants:

<!-- Bad: requires two classes, breaks without dir attribute -->
<div class="ltr:ml-4 rtl:mr-4">...</div>

<!-- Good: single class, auto-mirrors based on dir -->
<div class="ms-4">...</div>

Reserve rtl: / ltr: variants only for cases logical properties cannot handle (e.g., directional icons, transforms).

Some utilities have no logical form and stay physical in v4: translate-x-* (slide-in drawers and sheets), origin-left / origin-right, and bg-linear-to-r / bg-linear-to-l. Pair each with an rtl: override, for example -translate-x-full rtl:translate-x-full for a drawer that enters from the start edge.

Tailwind v4 note: v4 (GA since early 2025, currently v4.3) uses CSS-first configuration (@import "tailwindcss" in CSS) instead of tailwind.config.js. Logical utilities work identically in both v3 and v4. As of v4.2 (February 2026) the logical inset utilities start-*/end-* are deprecated in favor of inset-s-*/inset-e-* (the old names still work; no removal date has been announced); the margin/padding utilities ms-*/me-*/ps-*/pe-* are unaffected.

Next.js App Router:

// app/[locale]/layout.tsx (a plain app/layout.tsx receives no locale param)
import { Heebo } from 'next/font/google';

const heebo = Heebo({
  subsets: ['hebrew', 'latin'],
  weight: ['400', '500', '700'],
});

export default async function RootLayout({
  children,
  params,
}: {
  children: React.ReactNode;
  params: Promise<{ locale: string }>;
}) {
  const { locale } = await params;
  const isRTL = locale === 'he';

  return (
    <html lang={locale} dir={isRTL ? 'rtl' : 'ltr'}>
      <body className={heebo.className}>{children}</body>
    </html>
  );
}

next/font self-hosts the font (no external Google Fonts requests, zero layout shift).

React with MUI:

Current MUI (v9 as of 2026) uses the official fork @mui/stylis-plugin-rtl, not the older community stylis-plugin-rtl package. The official fork fixes CSS-layers issues and supports current Stylis versions; this has been the recommended setup since MUI v6.

import { createTheme, ThemeProvider } from '@mui/material/styles';
import { CacheProvider } from '@emotion/react';
import createCache from '@emotion/cache';
import rtlPlugin from '@mui/stylis-plugin-rtl';
import { prefixer } from 'stylis';

const cacheRtl = createCache({
  key: 'muirtl',
  stylisPlugins: [prefixer, rtlPlugin],
});

const theme = createTheme({ direction: 'rtl' });

In the Next.js App Router, pass the same options to MUI's AppRouterCacheProvider (from @mui/material-nextjs/v16-appRouter, matching your Next.js major) instead of building a separate cache: <AppRouterCacheProvider options={{ key: 'muirtl', stylisPlugins: [prefixer, rtlPlugin] }}>, with <ThemeProvider theme={theme}> inside it. Its options prop is passed straight to Emotion's createCache.

@mui/stylis-plugin-rtl exposes only a default export, so a named import { rtlPlugin } compiles but yields undefined, and Emotion silently skips the plugin: the app looks LTR with no error. Confirm the exact import name and setup against the current MUI RTL guide (https://mui.com/material-ui/customization/right-to-left/) for your MUI version.

Portalled UI (modals, dropdowns, tooltips, toasts). Components rendered through a portal (React createPortal, Radix, MUI Menu, Floating UI) mount at document.body and inherit direction from there, but many libraries assume LTR. Set dir on <html> AND pass the library's own direction setting: Radix needs a <DirectionProvider dir="rtl"> wrapper, MUI needs direction: 'rtl' in the theme. Otherwise popovers open on the wrong side even when the rest of the page is correct.

Step 7: Common Pitfalls to Check

1. Directional icons -- mirror them (see Step 4 for which icons to flip and which to leave)
2. Progress bars -- should fill from right to left
3. Sliders/carousels -- swipe direction should reverse
4. Form labels -- should be right-aligned
5. Breadcrumbs -- separator direction should reverse
6. Tables -- columns reorder automatically, but force numeric, code, and date cells back to LTR with <td dir="ltr">, and align them consistently (for example text-align: end; alignment alone does not change direction)
7. Charts -- x-axis may need to reverse for Hebrew readers (SVG has no logical properties, so use the charting library's reversed/rtl option, not CSS)
8. Shadows and gradients -- physical offsets/angles do not auto-flip (see Step 3)
9. Fixed and sticky chrome (headers, toasts, FABs, drawers) -- hardcoded left: 0 / right: 0 does not flip; use inset-inline-start / inset-inline-end
10. Scrollbars sit on the left in RTL -- reserve space with scrollbar-gutter: stable (Tailwind v4.3+: scrollbar-gutter-stable) to avoid reflow; text-wrap: balance improves Hebrew headings

Step 8: Verify the RTL Layout

Authoring rules are not enough, verify before shipping:

• Flip the whole app to dir="rtl" and scan for anything that did not move (it is still using a physical property).
• Test one canonical mixed string in every text surface: שלום John +972 50-123-4567 ₪1,234 exercises Hebrew, Latin, an international phone number, and a currency amount at once.
• Open every modal, dropdown, tooltip, and toast (portalled UI is the most common RTL miss).
• Check fixed/sticky chrome, charts/SVG, and form fields with dir="auto".
• Automate it: render the same pages twice under dir="rtl" and dir="ltr" in Playwright and screenshot-diff them. Manual flipping is the step teams skip first, and a physical property that creeps back in shows up as a pixel diff long before a user reports it.

Examples

Example 1: Convert LTR Component to RTL

User says: "Make this card component work in Hebrew"

Before (LTR-only):

.card {
  margin-left: 16px;
  padding-right: 12px;
  text-align: left;
  border-left: 3px solid blue;
}

After (RTL-compatible):

.card {
  margin-inline-start: 16px;
  padding-inline-end: 12px;
  text-align: start;
  border-inline-start: 3px solid blue;
}

With Tailwind, replace ml-4 pr-3 text-left border-l-4 with ms-4 pe-3 text-start border-s-4.

Example 2: Bidi Text Issue

User says: "Numbers are showing backwards in my Hebrew text"

<!-- Wrong: space-separated groups render in reverse order (4450 321 050) -->
<p>התקשרו אלינו: 050 321 4450</p>

<!-- Wrong: the +972 prefix jumps to the far end (50-321-4450 972+) -->
<p>התקשרו אלינו: +972 50-321-4450</p>

<!-- Correct: isolate the LTR content -->
<p>התקשרו אלינו: <span dir="ltr">+972 50-321-4450</span></p>

A hyphen-only number such as 050-321-4450 renders correctly without help, so check the actual format before blaming bidi. Use unicode-bidi: isolate with direction: ltr on the containing span for CSS-only solutions.

Example 3: Tailwind RTL Navigation

User says: "My sidebar is on the wrong side in Hebrew"

<!-- Bad: sidebar stuck on left -->
<aside class="fixed left-0 w-64">...</aside>

<!-- Good: sidebar auto-mirrors (inset-s-0; start-0 is the deprecated alias) -->
<aside class="fixed inset-s-0 w-64">...</aside>

<!-- Back arrow icon still needs rtl: variant (horizontal flip, not rotate-180 which also flips vertically) -->
<button class="rtl:-scale-x-100">
  <ArrowLeftIcon />
</button>

Bundled Resources

References

• references/css-logical-properties.md - Complete physical-to-logical CSS property mapping table (margin, padding, border, positioning, text alignment, sizing) plus Hebrew font stack recommendations for sans-serif, serif, and monospace. Consult when converting any LTR stylesheet to RTL-compatible logical properties or choosing Hebrew web fonts.

Gotchas

• CSS text-align: left is wrong for Hebrew. Use text-align: start which respects the document direction. Agents frequently hardcode left alignment in CSS.
• margin-left and padding-right do not flip in RTL mode. Use CSS logical properties: margin-inline-start and padding-inline-end instead. Agents trained on LTR CSS will generate physical properties.
• Flexbox row direction auto-reverses in RTL, but row-reverse also reverses, causing a double-flip back to LTR order. Agents may add row-reverse thinking it creates RTL, but it actually creates LTR within an RTL context.
• Phone numbers, credit card numbers, code, file paths, and CLI commands must remain LTR even inside RTL containers. Wrap inline values in <bdo dir="ltr">, and set code, pre, kbd, samp { direction: ltr; unicode-bidi: isolate; } once in the RTL theme so every code block and keyboard shortcut is covered. Agents often let these inherit RTL, which moves a trailing slash or flag to the wrong end.
• In an RTL scroll container, scrollLeft is 0 at the start (rightmost) position and becomes increasingly NEGATIVE toward the end. Custom carousels and "next" buttons written as el.scrollLeft += 300, or clamped with Math.max(0, ...), scroll the wrong way or stick at the start. Use el.scrollBy({ left: isRtl ? -300 : 300 }) and treat scrollLeft <= 0 as the normal RTL range.

Reference Links

Troubleshooting

Error: "Text alignment looks wrong"

Cause: Using text-align: left instead of text-align: start Solution: Replace all left/right in text-align with start/end.

Error: "Layout not mirroring"

Cause: Using physical margin/padding instead of logical properties Solution: Replace all margin-left/margin-right with margin-inline-start/margin-inline-end.