diff --git a/public/scripts/binary.js b/public/scripts/binary.js
index 8effa3c..443272d 100644
--- a/public/scripts/binary.js
+++ b/public/scripts/binary.js
@@ -1,10 +1,3 @@
-/* Binary simulator for Computing:Box
-   - Wrap bits every 8 (CSS handles layout)
-   - Bit width 4..64
-   - Unsigned + Two’s complement toggle (WORKING)
-   - Bulbs + toggle switches for each bit
-*/
-
 const bitsGrid = document.getElementById("bitsGrid");
 const denaryEl = document.getElementById("denaryNumber");
 const binaryEl = document.getElementById("binaryNumber");
@@ -21,42 +14,87 @@ const btnShiftRight = document.getElementById("btnShiftRight");
 const btnCustomBinary = document.getElementById("btnCustomBinary");
 const btnCustomDenary = document.getElementById("btnCustomDenary");
 
-let bitCount = clampInt(Number(bitsInput?.value ?? 8), 4, 64);
-let isTwos = false;
+let bitCount = 8;              // 4..64
+let mode = "unsigned";         // "unsigned" | "twos"
 
 // bits[0] is MSB, bits[bitCount-1] is LSB
 let bits = new Array(bitCount).fill(false);
 
+/* -----------------------------
+   Helpers
+----------------------------- */
 function clampInt(n, min, max) {
   n = Number(n);
-  if (!Number.isInteger(n)) n = min;
-  return Math.max(min, Math.min(max, n));
+  if (!Number.isFinite(n)) return min;
+  return Math.max(min, Math.min(max, Math.trunc(n)));
 }
 
-function pow2(exp) {
-  // safe up to 2^63 in JS integer precision? (JS uses float) but our usage is display/control, ok.
-  return 2 ** exp;
+function maxUnsigned(nBits) {
+  return (2 ** nBits) - 1;
+}
+
+function minTwos(nBits) {
+  return -(2 ** (nBits - 1));
+}
+
+function maxTwos(nBits) {
+  return (2 ** (nBits - 1)) - 1;
+}
+
+function bitsToUnsigned() {
+  // MSB..LSB
+  let v = 0;
+  for (let i = 0; i < bitCount; i++) {
+    if (bits[i]) v += 2 ** (bitCount - 1 - i);
+  }
+  return v;
+}
+
+function bitsToSigned() {
+  const u = bitsToUnsigned();
+  if (mode !== "twos") return u;
+  // if MSB is 1 => negative
+  if (!bits[0]) return u;
+  return u - (2 ** bitCount);
+}
+
+function setBitsFromUnsigned(u) {
+  u = clampInt(u, 0, maxUnsigned(bitCount));
+  for (let i = 0; i < bitCount; i++) {
+    const place = 2 ** (bitCount - 1 - i);
+    bits[i] = u >= place;
+    if (bits[i]) u -= place;
+  }
+}
+
+function setBitsFromSigned(s) {
+  // convert signed -> unsigned representation
+  const min = minTwos(bitCount);
+  const max = maxTwos(bitCount);
+  s = clampInt(s, min, max);
+  const u = s < 0 ? (2 ** bitCount) + s : s;
+  setBitsFromUnsigned(u);
 }
 
 /* -----------------------------
-   Build UI (bulbs + switches)
+   Build UI
 ----------------------------- */
-function buildBits(count) {
-  bitCount = clampInt(count, 4, 64);
-  bits = resizeBits(bits, bitCount);
-
+function buildBitsUI() {
   bitsGrid.innerHTML = "";
 
+  // Force wrap every 8 bits visually
+  // CSS already does repeat(8,...). Nothing else needed.
+
   for (let i = 0; i < bitCount; i++) {
-    const exp = bitCount - 1 - i;  // MSB has highest exponent
-    const value = pow2(exp);
+    const placeValue = 2 ** (bitCount - 1 - i);
 
     const bit = document.createElement("div");
     bit.className = "bit";
+
     bit.innerHTML = `
-      <div class="bulb" id="bulb-${i}" aria-hidden="true"></div>
-      <div class="bitVal">${value}</div>
-      <label class="switch" aria-label="Toggle bit ${value}">
+      <div class="bulb" id="bulb-${i}" aria-hidden="true">💡</div>
+      <div class="bitVal num">${placeValue}</div>
+      <label class="switch" aria-label="Toggle bit ${placeValue}">
         <input type="checkbox" data-index="${i}">
         <span class="slider"></span>
       </label>
@@ -65,114 +103,65 @@ function buildBits(count) {
     bitsGrid.appendChild(bit);
   }
 
-  hookSwitches();
-  syncUI();
-}
-
-function resizeBits(oldBits, newCount) {
-  // keep LSB end stable when changing bit width:
-  // align old bits to the right (LSB)
-  const out = new Array(newCount).fill(false);
-  const copy = Math.min(oldBits.length, newCount);
-
-  for (let k = 0; k < copy; k++) {
-    // copy from end (LSB)
-    out[newCount - 1 - k] = oldBits[oldBits.length - 1 - k];
-  }
-  return out;
-}
-
-function hookSwitches() {
+  // Hook switches
   bitsGrid.querySelectorAll('input[type="checkbox"][data-index]').forEach((input) => {
     input.addEventListener("change", () => {
       const i = Number(input.dataset.index);
       bits[i] = input.checked;
       updateReadout();
-      updateBulb(i);
     });
   });
+
+  syncUI();
 }
 
 /* -----------------------------
-   Mode toggle (Unsigned <-> Two’s)
+   Sync + Display
 ----------------------------- */
-function setModeTwos(on) {
-  isTwos = !!on;
-
-  modeHint.textContent = isTwos
-    ? "Tip: In two’s complement, the left-most bit (MSB) represents a negative value."
-    : "Tip: In unsigned binary, all bits represent positive values.";
-
-  // Just re-calc denary using current bit pattern
-  updateReadout();
-}
-
-modeToggle?.addEventListener("change", () => setModeTwos(modeToggle.checked));
-
-/* -----------------------------
-   Calculations
------------------------------ */
-function getUnsignedValue() {
-  let n = 0;
-  for (let i = 0; i < bitCount; i++) {
-    if (!bits[i]) continue;
-    const exp = bitCount - 1 - i;
-    n += pow2(exp);
-  }
-  return n;
-}
-
-function getTwosValue() {
-  // MSB has negative weight
-  let n = 0;
-  for (let i = 0; i < bitCount; i++) {
-    if (!bits[i]) continue;
-    const exp = bitCount - 1 - i;
-    if (i === 0) n -= pow2(exp);   // MSB
-    else n += pow2(exp);
-  }
-  return n;
-}
-
-function getDenary() {
-  return isTwos ? getTwosValue() : getUnsignedValue();
-}
-
-function getBinaryString() {
-  return bits.map(b => (b ? "1" : "0")).join("");
-}
-
-/* -----------------------------
-   UI updates
------------------------------ */
-function updateBulb(i) {
-  const bulb = document.getElementById(`bulb-${i}`);
-  if (bulb) bulb.classList.toggle("on", bits[i]);
-}
-
-function updateReadout() {
-  denaryEl.textContent = String(getDenary());
-  binaryEl.textContent = getBinaryString();
-}
-
 function syncUI() {
   bitsGrid.querySelectorAll('input[type="checkbox"][data-index]').forEach((input) => {
     const i = Number(input.dataset.index);
     input.checked = !!bits[i];
-    updateBulb(i);
+
+    const bulb = document.getElementById(`bulb-${i}`);
+    if (bulb) bulb.classList.toggle("on", !!bits[i]);
   });
+
   updateReadout();
 }
 
+function updateReadout() {
+  const binaryStr = bits.map((b) => (b ? "1" : "0")).join("");
+  binaryEl.textContent = binaryStr;
+
+  const d = bitsToSigned();
+  denaryEl.textContent = String(d);
+
+  // hint text
+  if (mode === "twos") {
+    modeHint.textContent =
+      "Tip: In two’s complement, the left-most bit (MSB) represents a negative value.";
+  } else {
+    modeHint.textContent =
+      "Tip: In unsigned binary, all bits represent positive values.";
+  }
+
+  // bulbs
+  for (let i = 0; i < bitCount; i++) {
+    const bulb = document.getElementById(`bulb-${i}`);
+    if (bulb) bulb.classList.toggle("on", !!bits[i]);
+  }
+}
+
 /* -----------------------------
-   Set from Binary / Denary
+   Input setters
 ----------------------------- */
 function setFromBinary(bin) {
   const clean = String(bin).replace(/\s+/g, "");
   if (!/^[01]+$/.test(clean)) return false;
 
   const padded = clean.slice(-bitCount).padStart(bitCount, "0");
-  bits = [...padded].map(ch => ch === "1");
+  bits = [...padded].map((ch) => ch === "1");
   syncUI();
   return true;
 }
@@ -180,48 +169,14 @@ function setFromBinary(bin) {
 function setFromDenary(n) {
   if (!Number.isInteger(n)) return false;
 
-  if (!isTwos) {
-    const min = 0;
-    const max = pow2(bitCount) - 1;
-    if (n < min || n > max) return false;
-
-    // unsigned fill from MSB->LSB
-    let remaining = n;
-    bits = bits.map((_, i) => {
-      const exp = bitCount - 1 - i;
-      const value = pow2(exp);
-      if (remaining >= value) {
-        remaining -= value;
-        return true;
-      }
-      return false;
-    });
-
-    syncUI();
-    return true;
+  if (mode === "twos") {
+    if (n < minTwos(bitCount) || n > maxTwos(bitCount)) return false;
+    setBitsFromSigned(n);
+  } else {
+    if (n < 0 || n > maxUnsigned(bitCount)) return false;
+    setBitsFromUnsigned(n);
   }
 
-  // Two's complement bounds
-  const min = -pow2(bitCount - 1);
-  const max = pow2(bitCount - 1) - 1;
-  if (n < min || n > max) return false;
-
-  // Convert to raw unsigned representation:
-  // if negative, represent as 2^bitCount + n
-  let raw = n;
-  if (raw < 0) raw = pow2(bitCount) + raw;
-
-  let remaining = raw;
-  bits = bits.map((_, i) => {
-    const exp = bitCount - 1 - i;
-    const value = pow2(exp);
-    if (remaining >= value) {
-      remaining -= value;
-      return true;
-    }
-    return false;
-  });
-
   syncUI();
   return true;
 }
@@ -230,72 +185,89 @@ function setFromDenary(n) {
    Shifts
 ----------------------------- */
 function shiftLeft() {
-  // drop MSB, append 0 at LSB
+  // left shift: drop MSB, append 0
   bits.shift();
   bits.push(false);
   syncUI();
 }
 
 function shiftRight() {
-  // unsigned: logical shift right (prepend 0)
-  // twos: arithmetic shift right (prepend old MSB)
+  // right shift:
+  // unsigned = logical (prepend 0)
+  // twos = arithmetic (preserve MSB)
   const msb = bits[0];
   bits.pop();
-  bits.unshift(isTwos ? msb : false);
+  bits.unshift(mode === "twos" ? msb : false);
   syncUI();
 }
 
 /* -----------------------------
-   Bit width controls
+   Mode + Bit width
 ----------------------------- */
-function applyBitCount(next) {
-  const v = clampInt(next, 4, 64);
-  bitsInput.value = String(v);
-  buildBits(v);
+function setMode(nextMode) {
+  if (nextMode !== "unsigned" && nextMode !== "twos") return;
+
+  // keep the *bit pattern* the same, just interpret differently
+  mode = nextMode;
+  updateReadout();
 }
 
-btnBitsUp?.addEventListener("click", () => applyBitCount(bitCount + 1));
-btnBitsDown?.addEventListener("click", () => applyBitCount(bitCount - 1));
+function setBitCount(nextCount) {
+  nextCount = clampInt(nextCount, 4, 64);
 
-bitsInput?.addEventListener("change", () => {
-  applyBitCount(Number(bitsInput.value));
-});
+  if (nextCount === bitCount) return;
+
+  // preserve current binary string as much as possible (keep least significant bits)
+  const currentBinary = bits.map((b) => (b ? "1" : "0")).join("");
+  bitCount = nextCount;
+  bitsInput.value = String(bitCount);
+
+  bits = new Array(bitCount).fill(false);
+  buildBitsUI();
+  setFromBinary(currentBinary); // reapply into new width (LSB-preserving)
+}
 
 /* -----------------------------
-   Buttons
+   Wire up controls
 ----------------------------- */
-btnShiftLeft?.addEventListener("click", shiftLeft);
-btnShiftRight?.addEventListener("click", shiftRight);
-
-btnCustomBinary?.addEventListener("click", () => {
-  const v = prompt(`Enter a ${bitCount}-bit binary number:`);
-  if (v === null) return;
-  if (!setFromBinary(v)) alert("Invalid input. Use only 0 and 1.");
+modeToggle.addEventListener("change", () => {
+  setMode(modeToggle.checked ? "twos" : "unsigned");
 });
 
-btnCustomDenary?.addEventListener("click", () => {
-  const min = isTwos ? -pow2(bitCount - 1) : 0;
-  const max = isTwos ? (pow2(bitCount - 1) - 1) : (pow2(bitCount) - 1);
+btnBitsUp.addEventListener("click", () => setBitCount(bitCount + 1));
+btnBitsDown.addEventListener("click", () => setBitCount(bitCount - 1));
+
+bitsInput.addEventListener("change", () => setBitCount(bitsInput.value));
+bitsInput.addEventListener("keydown", (e) => {
+  if (e.key === "Enter") setBitCount(bitsInput.value);
+});
+
+btnShiftLeft.addEventListener("click", shiftLeft);
+btnShiftRight.addEventListener("click", shiftRight);
+
+btnCustomBinary.addEventListener("click", () => {
+  const v = prompt(`Enter a ${bitCount}-bit binary number:`);
+  if (v === null) return;
+  if (!setFromBinary(v)) alert("Invalid binary. Use only 0 and 1.");
+});
+
+btnCustomDenary.addEventListener("click", () => {
+  const min = mode === "twos" ? minTwos(bitCount) : 0;
+  const max = mode === "twos" ? maxTwos(bitCount) : maxUnsigned(bitCount);
 
   const v = prompt(`Enter a denary number (${min} to ${max}):`);
   if (v === null) return;
 
   const n = Number(v);
   if (!Number.isInteger(n) || !setFromDenary(n)) {
-    alert(`Invalid input. Enter an integer from ${min} to ${max}.`);
+    alert(`Invalid denary. Enter an integer from ${min} to ${max}.`);
   }
 });
 
 /* -----------------------------
-   INIT
+   Init
 ----------------------------- */
-function init() {
-  // default mode: unsigned
-  setModeTwos(false);
-  modeToggle.checked = false;
-
-  // build initial bits
-  applyBitCount(bitCount);
-}
-
-init();
+bitsInput.value = String(bitCount);
+modeToggle.checked = false; // unsigned by default
+buildBitsUI();
+updateReadout();
diff --git a/src/components/Footer.astro b/src/components/Footer.astro
new file mode 100644
index 0000000..1dd990e
--- /dev/null
+++ b/src/components/Footer.astro
@@ -0,0 +1,13 @@
+<footer class="siteFooter">
+  <div class="inner">
+    <div class="muted">Computer Science Concept Simulators</div>
+    <div class="muted">© {new Date().getFullYear()} Computing:Box · Created with ❤️ by Mr Lyall</div>
+    <div class="muted">Powered by ADCM Networks</div>
+  </div>
+
+  <style>
+    .siteFooter{ border-top:1px solid rgba(255,255,255,.10); background:rgba(0,0,0,.12); }
+    .inner{ max-width:1200px; margin:0 auto; padding:18px 20px; display:flex; flex-direction:column; gap:6px; }
+    .muted{ color:rgba(255,255,255,.60); font-size:13px; }
+  </style>
+</footer>
diff --git a/src/components/Header.astro b/src/components/Header.astro
new file mode 100644
index 0000000..a3e916a
--- /dev/null
+++ b/src/components/Header.astro
@@ -0,0 +1,22 @@
+<header class="siteHeader">
+  <div class="inner">
+    <a class="brand" href="/">Computing:Box</a>
+
+    <nav class="nav">
+      <a href="/binary">Binary</a>
+      <a href="/hexadecimal/gcse-hexadecimal">Hexadecimal</a>
+      <a href="/hex-colours">Hex Colours</a>
+      <a href="/logic-gates">Logic Gates</a>
+      <a href="/about">About</a>
+    </nav>
+  </div>
+
+  <style>
+    .siteHeader{ border-bottom:1px solid rgba(255,255,255,.10); background:rgba(0,0,0,.12); }
+    .inner{ max-width:1200px; margin:0 auto; padding:14px 20px; display:flex; align-items:center; justify-content:space-between; gap:16px; }
+    .brand{ color:#fff; text-decoration:none; font-weight:800; letter-spacing:.02em; }
+    .nav{ display:flex; gap:14px; flex-wrap:wrap; }
+    .nav a{ color:rgba(255,255,255,.85); text-decoration:none; font-weight:700; font-size:14px; }
+    .nav a:hover{ color:#fff; text-decoration:underline; }
+  </style>
+</header>
diff --git a/src/layouts/BaseLayout.astro b/src/layouts/BaseLayout.astro
index 7a7a8de..588c172 100644
--- a/src/layouts/BaseLayout.astro
+++ b/src/layouts/BaseLayout.astro
@@ -1,26 +1,29 @@
 ---
-import SiteHeader from "../components/SiteHeader.astro";
-import SiteFooter from "../components/SiteFooter.astro";
+import Header from "../components/Header.astro";
+import Footer from "../components/Footer.astro";
 
 const { title = "Computing:Box" } = Astro.props;
 ---
+
 <!doctype html>
 <html lang="en">
   <head>
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width,initial-scale=1" />
     <title>{title}</title>
-
-    <!-- Global site styles -->
-    <link rel="stylesheet" href="/styles/global.css" />
   </head>
-  <body>
-    <SiteHeader />
 
-    <main class="site-main">
+  <body>
+    <Header />
+    <main class="page">
       <slot />
     </main>
+    <Footer />
 
-    <SiteFooter />
+    <style>
+      :root{ --bg:#1f2027; --text:#e8e8ee; }
+      body{ margin:0; background:var(--bg); color:var(--text); font-family:system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif; }
+      .page{ min-height: calc(100vh - 140px); }
+    </style>
   </body>
 </html>
diff --git a/src/pages/binary.astro b/src/pages/binary.astro
index a1a0949..4c6cd92 100644
--- a/src/pages/binary.astro
+++ b/src/pages/binary.astro
@@ -1,21 +1,19 @@
 ---
 import BaseLayout from "../layouts/BaseLayout.astro";
+import "../styles/binary.css";
 ---
 
 <BaseLayout title="Binary | Computing:Box">
-  <!-- Page-specific CSS -->
-  <link rel="stylesheet" href="/styles/binary.css" />
-
-  <main class="wrap">
+  <div class="wrap">
     <section class="topGrid">
-      <!-- LEFT: readout + buttons + bits -->
+      <!-- LEFT -->
       <div>
         <div class="readout">
           <div class="label">Denary</div>
-          <div id="denaryNumber" class="num denary">0</div>
+          <div id="denaryNumber" class="num">0</div>
 
           <div class="label">Binary</div>
-          <div id="binaryNumber" class="num binary">00000000</div>
+          <div id="binaryNumber" class="num">00000000</div>
 
           <div class="controls">
             <button class="btn" id="btnCustomBinary" type="button">Custom Binary</button>
@@ -27,25 +25,23 @@ import BaseLayout from "../layouts/BaseLayout.astro";
 
         <div class="divider"></div>
 
-        <!-- Bits render here (JS builds bulbs + switches) -->
         <section class="bits" id="bitsGrid" aria-label="Bit switches"></section>
       </div>
 
-      <!-- RIGHT: mode + bit width -->
+      <!-- RIGHT -->
       <aside class="panelCol">
         <div class="card">
           <div class="cardTitle">Mode</div>
 
           <div class="toggleRow">
-            <div class="toggleLabel" id="lblUnsigned">Unsigned</div>
+            <div class="toggleLabel">Unsigned</div>
 
-            <!-- SAME SWITCH STYLE as bit switches -->
             <label class="switch" aria-label="Toggle mode">
               <input id="modeToggle" type="checkbox" />
               <span class="slider"></span>
             </label>
 
-            <div class="toggleLabel" id="lblTwos">Two’s complement</div>
+            <div class="toggleLabel">Two’s complement</div>
           </div>
 
           <div class="hint" id="modeHint">
@@ -77,12 +73,11 @@ import BaseLayout from "../layouts/BaseLayout.astro";
             <button class="miniBtn" id="btnBitsUp" type="button" aria-label="Increase bits">+</button>
           </div>
 
-          <div class="hint">Minimum 4 bits, maximum 64 bits. Display wraps every 8 bits.</div>
+          <div class="hint">Minimum 4 bits, maximum 64 bits.</div>
         </div>
       </aside>
     </section>
-  </main>
+  </div>
 
-  <!-- Page-specific JS -->
   <script type="module" src="/scripts/binary.js"></script>
 </BaseLayout>
diff --git a/src/styles/binary.css b/src/styles/binary.css
index 6a03738..9d68932 100644
--- a/src/styles/binary.css
+++ b/src/styles/binary.css
@@ -1,68 +1,274 @@
-.binary-container {
-  max-width: 1100px;
-  margin: auto;
-  padding: 2rem;
-  color: #e0e0e0;
+:root{
+  --bg:#1f2027;
+  --panel2: rgba(255,255,255,.04);
+  --text:#e8e8ee;
+  --muted:#a9acb8;
+  --accent:#33ff7a;
+  --accent-dim: rgba(51,255,122,.15);
+  --line: rgba(255,255,255,.12);
 }
 
-.display {
-  text-align: center;
+@font-face{
+  font-family:"DSEG7ClassicRegular";
+  src:
+    url("/fonts/DSEG7Classic-Regular.woff") format("woff"),
+    url("/fonts/DSEG7Classic-Regular.ttf") format("truetype");
+  font-weight:400;
+  font-style:normal;
+  font-display:swap;
 }
 
-.label {
-  font-size: 1.2rem;
-  opacity: 0.7;
+.wrap{
+  max-width:1200px;
+  margin:0 auto;
+  padding:32px 20px 60px;
 }
 
-.number {
-  font-size: 3rem;
-  margin-bottom: 1rem;
-  color: #00ff66;
+.topGrid{
+  display:grid;
+  grid-template-columns: 1fr 340px;
+  gap:28px;
+  align-items:start;
 }
 
-.controls {
-  margin-top: 1rem;
+.readout{
+  text-align:center;
+  padding:10px 10px 0;
 }
 
-.controls button {
-  margin: 0.25rem;
-  padding: 0.6rem 1rem;
-  font-size: 1rem;
+.label{
+  letter-spacing:.18em;
+  font-weight:800;
+  color:var(--muted);
+  text-transform:uppercase;
+  font-size:14px;
+  margin-top:10px;
 }
 
-.bits {
-  display: grid;
-  grid-template-columns: repeat(8, 1fr);
-  gap: 1rem;
-  margin-top: 3rem;
+.num{
+  font-family:"DSEG7ClassicRegular", ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
+  font-weight:400;
+  color:var(--accent);
+  text-shadow: 0 0 18px var(--accent-dim);
 }
 
-.bit {
-  width: 40px;
-  height: 80px;
-  background: #333;
-  border-radius: 20px;
-  position: relative;
-  cursor: pointer;
+#denaryNumber{
+  font-size:84px;
+  line-height:1.0;
+  margin:6px 0 16px;
 }
 
-.bit::after {
-  content: "";
-  width: 32px;
-  height: 32px;
-  background: #555;
-  border-radius: 50%;
-  position: absolute;
-  bottom: 6px;
-  left: 4px;
-  transition: all 0.2s ease;
+#binaryNumber{
+  font-size:62px;
+  letter-spacing:.12em;
+  line-height:1.0;
+  margin:6px 0 18px;
+  word-break:break-word;
 }
 
-.bit.on {
-  background: #00c853;
+.controls{
+  margin-top:10px;
+  display:flex;
+  gap:12px;
+  justify-content:center;
+  flex-wrap:wrap;
 }
 
-.bit.on::after {
-  bottom: 42px;
-  background: #eaffea;
+.btn{
+  background:rgba(255,255,255,.06);
+  border:1px solid rgba(255,255,255,.14);
+  color:#fff;
+  padding:12px 14px;
+  border-radius:12px;
+  font-weight:800;
+  cursor:pointer;
+  min-width:160px;
+}
+.btn:active{ transform:translateY(1px); }
+
+.divider{
+  margin-top:26px;
+  border-top:1px solid var(--line);
+}
+
+/* Right panels */
+.panelCol{ display:flex; flex-direction:column; gap:14px; }
+.card{
+  background:var(--panel2);
+  border:1px solid rgba(255,255,255,.10);
+  border-radius:14px;
+  padding:14px;
+}
+.cardTitle{
+  letter-spacing:.18em;
+  font-weight:900;
+  color:var(--muted);
+  text-transform:uppercase;
+  font-size:12px;
+  margin:0 0 10px;
+}
+.hint{
+  color:var(--muted);
+  font-size:12px;
+  margin-top:8px;
+  line-height:1.35;
+}
+
+/* Toggle switch (used for Mode AND each bit) */
+.toggleRow{
+  display:flex;
+  align-items:center;
+  justify-content:space-between;
+  gap:10px;
+}
+.toggleLabel{
+  color:var(--text);
+  font-weight:800;
+  font-size:14px;
+}
+
+.switch{
+  position:relative;
+  width:56px;
+  height:34px;
+  display:inline-block;
+  flex:0 0 auto;
+}
+.switch input{
+  opacity:0;
+  width:0;
+  height:0;
+  position:absolute;
+}
+.slider{
+  position:absolute;
+  inset:0;
+  background:rgba(255,255,255,.10);
+  border:1px solid rgba(255,255,255,.14);
+  border-radius:999px;
+  transition:.18s ease;
+}
+.slider::before{
+  content:"";
+  position:absolute;
+  height:28px;
+  width:28px;
+  left:3px;
+  top:2px;
+  background:rgba(255,255,255,.92);
+  border-radius:50%;
+  transition:.18s ease;
+}
+.switch input:checked + .slider{
+  background:rgba(51,255,122,.20);
+  border-color:rgba(51,255,122,.55);
+}
+.switch input:checked + .slider::before{
+  transform:translateX(22px);
+  background:var(--accent);
+}
+
+/* Bit width control */
+.bitWidthRow{
+  display:grid;
+  grid-template-columns:44px 1fr 44px;
+  gap:10px;
+  align-items:center;
+}
+.miniBtn{
+  height:44px;
+  width:44px;
+  border-radius:12px;
+  background:rgba(255,255,255,.06);
+  border:1px solid rgba(255,255,255,.14);
+  color:#fff;
+  cursor:pointer;
+  font-weight:900;
+  font-size:18px;
+}
+.bitInputWrap{
+  background:rgba(255,255,255,.06);
+  border:1px solid rgba(255,255,255,.14);
+  border-radius:12px;
+  padding:10px 12px;
+  display:flex;
+  align-items:center;
+  justify-content:space-between;
+  gap:12px;
+}
+.bitInputLabel{
+  color:var(--muted);
+  font-size:12px;
+  font-weight:900;
+  letter-spacing:.18em;
+  text-transform:uppercase;
+}
+.bitInput{
+  width:86px;
+  text-align:right;
+  background:transparent;
+  border:none;
+  outline:none;
+  color:var(--accent);
+  font-family:"DSEG7ClassicRegular", ui-monospace, monospace;
+  font-size:28px;
+}
+.bitInput::-webkit-outer-spin-button,
+.bitInput::-webkit-inner-spin-button{ -webkit-appearance:none; margin:0; }
+
+/* Bits grid — force rows of 8, NO horizontal scrollbar */
+.bits{
+  margin-top:26px;
+  padding-top:22px;
+  display:grid;
+  grid-template-columns: repeat(8, minmax(90px, 1fr));
+  gap:18px;
+  align-items:end;
+  text-align:center;
+}
+
+/* Each bit */
+.bit{
+  display:flex;
+  flex-direction:column;
+  align-items:center;
+  gap:10px;
+  padding:8px 4px;
+}
+
+/* 💡 bulb */
+.bulb{
+  font-size:22px;
+  line-height:1;
+  opacity:.18;
+  filter: grayscale(100%);
+  transform: translateY(2px);
+  user-select:none;
+}
+.bulb.on{
+  opacity:1;
+  filter: none;
+  text-shadow: 0 0 14px rgba(255,216,107,.55);
+}
+
+.bitVal{
+  font-family:"DSEG7ClassicRegular", ui-monospace, monospace;
+  font-size:30px;
+  color:var(--text);
+  opacity:.95;
+  line-height:1;
+  min-height:34px;
+}
+
+@media (max-width: 980px){
+  .topGrid{ grid-template-columns: 1fr; }
+  #denaryNumber{ font-size:72px; }
+  #binaryNumber{ font-size:52px; }
+  .bits{ grid-template-columns: repeat(4, minmax(90px, 1fr)); } /* still neat on phones */
+}
+
+@media (max-width: 520px){
+  #denaryNumber{ font-size:62px; }
+  #binaryNumber{ font-size:44px; }
+  .btn{ min-width:140px; }
 }