text-wrap Balance & Pretty

:root {
  --bg: #0c0d10;
  --surface: #15161b;
  --surface-2: #1d1f27;
  --ink: #e9eaf0;
  --muted: #9a9cab;
  --accent: #8b5cf6;
  --accent-2: #22d3ee;
  --ok: #34d399;
  --warn: #fbbf24;
  --danger: #f87171;
  --line: rgba(255, 255, 255, 0.10);
  --line-2: rgba(255, 255, 255, 0.18);
  --r-sm: 8px;
  --r-md: 12px;
  --r-lg: 16px;
  --measure: 30ch;
}

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Inter", system-ui, sans-serif;
  line-height: 1.5;
  color: var(--ink);
  background:
    radial-gradient(1100px 600px at 82% -8%, rgba(139, 92, 246, 0.16), transparent 60%),
    radial-gradient(900px 520px at 6% 108%, rgba(34, 211, 238, 0.12), transparent 60%),
    var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.stage {
  max-width: 1080px;
  margin: 0 auto;
  padding: clamp(20px, 4vw, 52px) clamp(16px, 4vw, 40px) 56px;
}

/* ---------- Masthead ---------- */
.masthead {
  margin-bottom: 28px;
}

.eyebrow {
  margin: 0 0 12px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent-2);
}

.masthead__title {
  margin: 0 0 14px;
  font-size: clamp(30px, 6vw, 52px);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.05;
  text-wrap: balance;
}

.grad {
  background: linear-gradient(92deg, var(--accent), #c4b5fd);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.grad--2 {
  background: linear-gradient(92deg, var(--accent-2), #a5f3fc);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.masthead__sub {
  margin: 0;
  max-width: 62ch;
  color: var(--muted);
  font-size: clamp(15px, 2vw, 17px);
  text-wrap: pretty;
}

/* ---------- Controls ---------- */
.controls {
  display: grid;
  gap: 16px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: linear-gradient(180deg, var(--surface-2), var(--surface));
  box-shadow: 0 22px 50px -30px rgba(0, 0, 0, 0.9);
}

.controls__group {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 10px;
}

.switch {
  position: relative;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: rgba(255, 255, 255, 0.02);
  cursor: pointer;
  transition: border-color 0.18s ease, background 0.18s ease, transform 0.1s ease;
}

.switch:hover {
  border-color: var(--line-2);
  background: rgba(255, 255, 255, 0.05);
}

.switch:active {
  transform: translateY(1px);
}

.switch input {
  position: absolute;
  opacity: 0;
  width: 1px;
  height: 1px;
  pointer-events: none;
}

.switch__track {
  flex: 0 0 auto;
  width: 40px;
  height: 24px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--line-2);
  transition: background 0.2s ease, border-color 0.2s ease;
  position: relative;
}

.switch__thumb {
  position: absolute;
  top: 50%;
  left: 3px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--muted);
  transform: translateY(-50%);
  transition: transform 0.22s cubic-bezier(0.34, 1.56, 0.64, 1), background 0.2s ease;
}

.switch input:checked ~ .switch__track {
  background: linear-gradient(92deg, var(--accent), var(--accent-2));
  border-color: transparent;
}

.switch input:checked ~ .switch__track .switch__thumb {
  transform: translate(16px, -50%);
  background: #fff;
}

.switch input:focus-visible ~ .switch__track {
  outline: 2px solid var(--accent-2);
  outline-offset: 3px;
}

.switch__label {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.switch__label code {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 12.5px;
  color: var(--ink);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.switch__label small {
  font-size: 11px;
  color: var(--muted);
}

.switch__flag {
  margin-left: auto;
  align-self: flex-start;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--warn);
  border: 1px solid rgba(251, 191, 36, 0.4);
  background: rgba(251, 191, 36, 0.1);
  padding: 2px 6px;
  border-radius: 999px;
}

.switch.is-unsupported {
  opacity: 0.62;
  cursor: not-allowed;
}

.switch.is-unsupported:hover {
  border-color: var(--line);
  background: rgba(255, 255, 255, 0.02);
}

/* ---------- Measure slider ---------- */
.controls__measure {
  padding-top: 4px;
}

.slider {
  display: block;
}

.slider__top {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 8px;
}

.slider__top output {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 13px;
  color: var(--accent-2);
  font-weight: 500;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: #fff;
  border: 3px solid var(--accent);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
  transition: transform 0.12s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.12);
}

input[type="range"]::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: #fff;
  border: 3px solid var(--accent);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
}

input[type="range"]:focus-visible {
  outline: 2px solid var(--accent-2);
  outline-offset: 4px;
}

/* ---------- Status ---------- */
.status {
  margin: 16px 0 22px;
  font-size: 13.5px;
  color: var(--ink);
  display: flex;
  align-items: center;
  gap: 8px;
}

.status::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ok);
  box-shadow: 0 0 0 4px rgba(52, 211, 153, 0.16);
  flex: 0 0 auto;
}

/* ---------- Columns ---------- */
.columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}

.col {
  position: relative;
  padding: 22px 22px 26px;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--surface);
  overflow: hidden;
}

.col--on {
  border-color: rgba(139, 92, 246, 0.35);
  box-shadow: 0 0 0 1px rgba(139, 92, 246, 0.12) inset,
    0 24px 60px -34px rgba(139, 92, 246, 0.55);
}

.col__tag {
  display: inline-block;
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 11px;
  letter-spacing: 0.02em;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 3px 10px;
  margin-bottom: 16px;
}

.col--on .col__tag {
  color: #e9d9ff;
  border-color: rgba(139, 92, 246, 0.5);
  background: rgba(139, 92, 246, 0.12);
}

.headline {
  margin: 0 0 12px;
  max-width: var(--measure);
  font-size: clamp(20px, 3.2vw, 26px);
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.16;
  text-wrap: normal;
}

.col--on .headline {
  text-wrap: balance;
}

.byline {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12.5px;
  color: var(--muted);
  margin-bottom: 16px;
}

.byline .dot {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  flex: 0 0 auto;
}

.prose {
  max-width: var(--measure);
  font-family: "Source Serif 4", Georgia, serif;
  font-size: 16px;
  line-height: 1.62;
  color: #d7d9e4;
  text-wrap: normal;
}

.col--on .prose {
  text-wrap: pretty;
}

.prose p {
  margin: 0 0 1em;
}

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

/* Hanging punctuation — toggled per column */
.prose.is-hang {
  hanging-punctuation: first last;
}

/* Drop cap — toggled per column */
.prose.is-dropcap p:first-of-type::first-letter {
  -webkit-initial-letter: 3;
  initial-letter: 3;
  font-family: "Source Serif 4", Georgia, serif;
  font-weight: 600;
  color: var(--accent);
  margin-right: 0.08em;
  padding-right: 0.04em;
}

/* Fallback drop cap when initial-letter is unsupported */
@supports not (initial-letter: 3) {
  .prose.is-dropcap p:first-of-type::first-letter {
    font-size: 3.1em;
    line-height: 0.86;
    float: left;
    padding: 0.02em 0.08em 0 0;
    color: var(--accent);
    font-weight: 600;
  }
}

/* ---------- Legend ---------- */
.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 22px;
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-size: 12.5px;
  color: var(--muted);
}

.legend__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.chip {
  width: 12px;
  height: 12px;
  border-radius: 3px;
  flex: 0 0 auto;
}

.chip--bal {
  background: var(--accent);
}

.chip--orphan {
  background: var(--accent-2);
}

.chip--hang {
  background: var(--ok);
}

/* ---------- Responsive ---------- */
@media (max-width: 780px) {
  .columns {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 520px) {
  .stage {
    padding: 22px 16px 44px;
  }

  .controls__group {
    grid-template-columns: 1fr;
  }

  .headline {
    max-width: none;
  }

  .prose {
    max-width: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
  }
}

(function () {
  "use strict";

  // Shared article body. First paragraph opens with a quote so hanging-punctuation
  // and the drop cap both have something to act on. Deliberately worded to produce
  // a short "orphan" last line unless text-wrap: pretty intervenes.
  var BODY = [
    "“The line breaks nobody notices are the ones doing the most work,” says every " +
      "typographer who has ever agonized over a single ragged edge. For decades the browser " +
      "greedily filled each line and moved on, occasionally stranding one lonely word.",
    "text-wrap: pretty asks the engine to look ahead across the whole paragraph, trading a " +
      "little speed for a smoother right edge and, crucially, no orphaned final word dangling " +
      "on a line of its own.",
    "For headings, text-wrap: balance evens out the length of every line so a two-line title " +
      "never leaves a single small word marooned below a very long one. It is quietly the most " +
      "flattering line of CSS you can add to a page."
  ];

  var proseOff = document.getElementById("prose-off");
  var proseOn = document.getElementById("prose-on");

  function render(el) {
    el.innerHTML = BODY.map(function (t) {
      return "<p>" + t + "</p>";
    }).join("");
  }
  render(proseOff);
  render(proseOn);

  // ---- Feature detection -------------------------------------------------
  function supported(prop, value) {
    try {
      return window.CSS && CSS.supports(prop, value);
    } catch (e) {
      return false;
    }
  }

  var FEATURES = {
    "tw-balance": supported("text-wrap", "balance"),
    "tw-pretty": supported("text-wrap", "pretty"),
    "hang": supported("hanging-punctuation", "first"),
    // Safari ships the prefixed form; accept either.
    "dropcap":
      supported("initial-letter", "3") || supported("-webkit-initial-letter", "3")
  };

  var els = {
    balance: document.getElementById("tw-balance"),
    pretty: document.getElementById("tw-pretty"),
    hang: document.getElementById("hang"),
    dropcap: document.getElementById("dropcap")
  };

  var status = document.getElementById("status");

  function markUnsupported(inputId) {
    var input = document.getElementById(inputId);
    if (!input) return;
    var wrapper = input.closest(".switch");
    var flag = wrapper ? wrapper.querySelector("[data-flag]") : null;
    if (!FEATURES[inputId]) {
      input.checked = false;
      input.disabled = true;
      if (wrapper) wrapper.classList.add("is-unsupported");
      if (flag) flag.hidden = false;
    }
  }
  Object.keys(FEATURES).forEach(markUnsupported);

  // ---- Apply state -------------------------------------------------------
  var onHeadline = proseOn.parentElement.querySelector(".headline");

  function apply() {
    // Heading balance (ON column). When unsupported, class simply has no effect.
    onHeadline.style.textWrap = els.balance.checked ? "balance" : "normal";

    // Body pretty (ON column).
    proseOn.style.textWrap = els.pretty.checked ? "pretty" : "normal";

    // Hanging punctuation + drop cap apply to BOTH columns so the effect is
    // isolated from the balance/pretty comparison.
    proseOff.classList.toggle("is-hang", els.hang.checked);
    proseOn.classList.toggle("is-hang", els.hang.checked);
    proseOff.classList.toggle("is-dropcap", els.dropcap.checked);
    proseOn.classList.toggle("is-dropcap", els.dropcap.checked);

    announce();
  }

  function announce() {
    var on = [];
    if (els.balance.checked) on.push("balance");
    if (els.pretty.checked) on.push("pretty");
    if (els.hang.checked) on.push("hanging punctuation");
    if (els.dropcap.checked) on.push("drop cap");

    var msg;
    if (on.length === 0) {
      msg = "All enhancements off — both columns now use plain, greedy line wrapping.";
    } else {
      var list =
        on.length === 1
          ? on[0]
          : on.slice(0, -1).join(", ") + " and " + on[on.length - 1];
      msg =
        "Active: " +
        list +
        ". The right column shows the difference against plain wrapping on the left.";
    }
    status.textContent = msg;
  }

  ["balance", "pretty", "hang", "dropcap"].forEach(function (k) {
    els[k].addEventListener("change", apply);
  });

  // ---- Measure slider ----------------------------------------------------
  var measure = document.getElementById("measure");
  var measureOut = document.getElementById("measure-out");

  function setMeasure() {
    var ch = measure.value + "ch";
    document.documentElement.style.setProperty("--measure", ch);
    measureOut.textContent = ch;
  }
  measure.addEventListener("input", setMeasure);

  // ---- Init --------------------------------------------------------------
  setMeasure();
  apply();
})();

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <title>text-wrap Balance &amp; Pretty</title>
  <link rel="preconnect" href="https://fonts.googleapis.com" />
  <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
  <link
    href="https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&family=Source+Serif+4:opsz,[email protected],400;8..60,600&display=swap"
    rel="stylesheet"
  />
  <link rel="stylesheet" href="style.css" />
</head>
<body>
  <main class="stage">
    <header class="masthead">
      <p class="eyebrow">CSS Text &amp; Inline modules</p>
      <h1 class="masthead__title">text-wrap: <span class="grad">balance</span> &amp; <span class="grad grad--2">pretty</span></h1>
      <p class="masthead__sub">
        The same headline and article, rendered twice. Flip the switches and watch the
        browser's line breaker even out ragged headings, banish orphaned last words, and
        drop a serif cap into the margin — all in CSS, no layout math.
      </p>
    </header>

    <section class="controls" aria-label="Typography controls">
      <div class="controls__group" role="group" aria-label="Wrapping features">
        <label class="switch" data-prop="text-wrap-heading">
          <input type="checkbox" id="tw-balance" checked />
          <span class="switch__track"><span class="switch__thumb"></span></span>
          <span class="switch__label">
            <code>text-wrap: balance</code>
            <small>headings</small>
          </span>
          <span class="switch__flag" data-flag hidden>unsupported</span>
        </label>

        <label class="switch" data-prop="text-wrap-body">
          <input type="checkbox" id="tw-pretty" checked />
          <span class="switch__track"><span class="switch__thumb"></span></span>
          <span class="switch__label">
            <code>text-wrap: pretty</code>
            <small>body copy</small>
          </span>
          <span class="switch__flag" data-flag hidden>unsupported</span>
        </label>

        <label class="switch" data-prop="hanging-punctuation">
          <input type="checkbox" id="hang" />
          <span class="switch__track"><span class="switch__thumb"></span></span>
          <span class="switch__label">
            <code>hanging-punctuation</code>
            <small>optical margin</small>
          </span>
          <span class="switch__flag" data-flag hidden>unsupported</span>
        </label>

        <label class="switch" data-prop="initial-letter">
          <input type="checkbox" id="dropcap" />
          <span class="switch__track"><span class="switch__thumb"></span></span>
          <span class="switch__label">
            <code>initial-letter: 3</code>
            <small>drop cap</small>
          </span>
          <span class="switch__flag" data-flag hidden>unsupported</span>
        </label>
      </div>

      <div class="controls__measure">
        <label class="slider" for="measure">
          <span class="slider__top">
            <span>Column width</span>
            <output id="measure-out" for="measure">30ch</output>
          </span>
          <input type="range" id="measure" min="18" max="48" step="1" value="30" />
        </label>
      </div>
    </section>

    <p class="status" id="status" role="status" aria-live="polite">
      Balance and Pretty are on. Compare the two columns below.
    </p>

    <div class="columns">
      <!-- OFF column: plain wrapping baseline -->
      <article class="col col--off" aria-label="Default wrapping (no text-wrap)">
        <div class="col__tag">text-wrap: normal</div>
        <h2 class="headline">Great typography is invisible until the moment it isn't</h2>
        <div class="byline">
          <span class="dot"></span>
          <span>The Line Break Review</span>
          <span aria-hidden="true">·</span>
          <span>7 min read</span>
        </div>
        <div class="prose" id="prose-off"></div>
      </article>

      <!-- ON column: enhanced wrapping -->
      <article class="col col--on" aria-label="Enhanced wrapping (text-wrap balance and pretty)">
        <div class="col__tag">balance + pretty</div>
        <h2 class="headline">Great typography is invisible until the moment it isn't</h2>
        <div class="byline">
          <span class="dot"></span>
          <span>The Line Break Review</span>
          <span aria-hidden="true">·</span>
          <span>7 min read</span>
        </div>
        <div class="prose" id="prose-on"></div>
      </article>
    </div>

    <footer class="legend">
      <span class="legend__item"><i class="chip chip--bal"></i> balanced heading lines</span>
      <span class="legend__item"><i class="chip chip--orphan"></i> orphan / widow removed</span>
      <span class="legend__item"><i class="chip chip--hang"></i> punctuation in the margin</span>
    </footer>
  </main>

  <script src="script.js"></script>
</body>
</html>