Bootstrap 5 Full-Screen Overlay Menu

<section class="wdw-stage">
  <div class="container" style="max-width:1040px">
    <div class="wdw-fs wdw-card is-open" id="wdwFs">
      <header class="wdw-fs-bar d-flex align-items-center justify-content-between px-3 px-md-4">
        <a href="#" class="wdw-brand fw-bold wdw-heading fs-5 text-decoration-none">Studio Ora</a>
        <button class="wdw-burger" type="button" id="wdwBurger" aria-expanded="true" aria-controls="wdwOverlay" aria-label="Close menu">
          <span></span><span></span><span></span>
        </button>
      </header>

      <div class="wdw-fs-hero d-flex flex-column justify-content-center px-4 px-md-5" id="wdwHero" inert>
        <span class="wdw-eyebrow">Full-screen menu</span>
        <h1 class="wdw-heading display-4 mt-2 mb-3">Tap the menu button<br>in the top right</h1>
        <p class="wdw-muted fs-5 mb-0" style="max-width:34rem">The navigation takes over the whole screen, with large links that slide in one by one. Press Escape to close it.</p>
      </div>

      <div class="wdw-overlay-fs wdw-aurora" id="wdwOverlay">
        <nav aria-label="Main">
          <ul class="list-unstyled mb-0">
            <li style="--i:0"><a href="#"><span class="wdw-num">01</span>Home</a></li>
            <li style="--i:1"><a href="#"><span class="wdw-num">02</span>About</a></li>
            <li style="--i:2"><a href="#"><span class="wdw-num">03</span>Work</a></li>
            <li style="--i:3"><a href="#"><span class="wdw-num">04</span>Contact</a></li>
          </ul>
        </nav>
      </div>
    </div>
  </div>
</section>

/* Web Designer Wall library style — shared base for every Bootstrap 5 snippet.
   Indigo accent, Plus Jakarta Sans, soft cards, pill buttons. Works in light and dark. */
@import url("https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700;800&display=swap");

:root,
[data-bs-theme="light"] {
  --wdw-font: "Plus Jakarta Sans", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --bs-body-font-family: var(--wdw-font);
  --bs-primary: #4f46e5;
  --bs-primary-rgb: 79, 70, 229;
  --bs-primary-text-emphasis: #3730a3;
  --bs-primary-bg-subtle: #eef2ff;
  --bs-primary-border-subtle: #c7d2fe;
  --bs-link-color: #4f46e5;
  --bs-link-color-rgb: 79, 70, 229;
  --bs-link-hover-color: #4338ca;
  --bs-link-hover-color-rgb: 67, 56, 202;
  --bs-focus-ring-color: rgba(79, 70, 229, 0.25);
  --bs-border-radius: 0.75rem;
  --bs-border-radius-lg: 1rem;
  --bs-border-radius-xl: 1.25rem;
  --wdw-radius-card: 1.25rem;
  --wdw-shadow: 0 1px 2px rgba(16, 24, 40, 0.05), 0 16px 40px -16px rgba(16, 24, 40, 0.22);
  --wdw-shadow-sm: 0 1px 2px rgba(16, 24, 40, 0.06), 0 4px 12px -4px rgba(16, 24, 40, 0.12);
  --wdw-stage: #f5f6fb;
}

[data-bs-theme="dark"] {
  --bs-primary: #818cf8;
  --bs-primary-rgb: 129, 140, 248;
  --bs-primary-text-emphasis: #c7d2fe;
  --bs-primary-bg-subtle: rgba(129, 140, 248, 0.14);
  --bs-primary-border-subtle: rgba(129, 140, 248, 0.35);
  --bs-link-color: #a5b4fc;
  --bs-link-color-rgb: 165, 180, 252;
  --bs-link-hover-color: #c7d2fe;
  --bs-link-hover-color-rgb: 199, 210, 254;
  --bs-focus-ring-color: rgba(129, 140, 248, 0.35);
  --wdw-shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 16px 40px -16px rgba(0, 0, 0, 0.7);
  --wdw-shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4), 0 4px 12px -4px rgba(0, 0, 0, 0.5);
  --wdw-stage: #0f1117;
}

body { font-family: var(--wdw-font); -webkit-font-smoothing: antialiased; }

/* Bootstrap compiles its blue into these components; point them at the accent. */
.btn-primary {
  --bs-btn-bg: var(--bs-primary); --bs-btn-border-color: var(--bs-primary);
  --bs-btn-hover-bg: #4338ca; --bs-btn-hover-border-color: #4338ca;
  --bs-btn-active-bg: #3730a3; --bs-btn-active-border-color: #3730a3;
  --bs-btn-disabled-bg: var(--bs-primary); --bs-btn-disabled-border-color: var(--bs-primary);
  --bs-btn-focus-shadow-rgb: var(--bs-primary-rgb);
}
[data-bs-theme="dark"] .btn-primary { --bs-btn-color: #0f1117; --bs-btn-hover-bg: #a5b4fc; --bs-btn-hover-border-color: #a5b4fc; --bs-btn-hover-color: #0f1117; --bs-btn-active-color: #0f1117; }
.btn-outline-primary {
  --bs-btn-color: var(--bs-primary); --bs-btn-border-color: var(--bs-primary);
  --bs-btn-hover-bg: var(--bs-primary); --bs-btn-hover-border-color: var(--bs-primary);
  --bs-btn-active-bg: var(--bs-primary); --bs-btn-active-border-color: var(--bs-primary);
  --bs-btn-focus-shadow-rgb: var(--bs-primary-rgb);
}
.btn { --bs-btn-font-weight: 600; min-height: 44px; display: inline-flex; align-items: center; justify-content: center; gap: .5rem; }
.btn-sm { min-height: 36px; }
.form-control, .form-select { min-height: 44px; border-radius: .75rem; }
.form-control:focus, .form-select:focus, .form-check-input:focus { border-color: rgba(var(--bs-primary-rgb), .6); box-shadow: 0 0 0 .25rem var(--bs-focus-ring-color); }
.form-check-input:checked { background-color: var(--bs-primary); border-color: var(--bs-primary); }
.nav-pills { --bs-nav-pills-link-active-bg: var(--bs-primary); }
.nav { --bs-nav-link-color: var(--bs-secondary-color); --bs-nav-link-hover-color: var(--bs-emphasis-color); }
.pagination { --bs-pagination-active-bg: var(--bs-primary); --bs-pagination-active-border-color: var(--bs-primary); --bs-pagination-color: var(--bs-body-color); --bs-pagination-focus-box-shadow: 0 0 0 .25rem var(--bs-focus-ring-color); }
.progress, .progress-stacked { --bs-progress-bar-bg: var(--bs-primary); }
.list-group { --bs-list-group-active-bg: var(--bs-primary); --bs-list-group-active-border-color: var(--bs-primary); }
.dropdown-menu { --bs-dropdown-link-active-bg: var(--bs-primary); border-radius: .875rem; box-shadow: var(--wdw-shadow-sm); }
.accordion { --bs-accordion-active-bg: var(--bs-primary-bg-subtle); --bs-accordion-active-color: var(--bs-primary-text-emphasis); --bs-accordion-btn-focus-box-shadow: 0 0 0 .25rem var(--bs-focus-ring-color); }
.badge { font-weight: 600; }

/* Library building blocks — use these instead of re-inventing them per snippet. */
.wdw-stage { min-height: 100vh; display: flex; align-items: center; background: var(--wdw-stage); padding-block: 3rem; }
.wdw-card { background: var(--bs-body-bg); border: 1px solid var(--bs-border-color-translucent); border-radius: var(--wdw-radius-card); box-shadow: var(--wdw-shadow); }
.wdw-card-sm { background: var(--bs-body-bg); border: 1px solid var(--bs-border-color-translucent); border-radius: 1rem; box-shadow: var(--wdw-shadow-sm); }
.wdw-aurora { position: relative; color: #fff; background: radial-gradient(60% 55% at 100% 0, #818cf8 0, transparent 70%), radial-gradient(65% 60% at 0 100%, #ec4899 0, transparent 65%), #1e1b4b; }
.wdw-eyebrow { display: inline-block; font-size: .75rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; color: var(--bs-primary); }
.wdw-heading { font-weight: 800; letter-spacing: -.02em; color: var(--bs-emphasis-color); }
.wdw-muted { color: var(--bs-secondary-color); }
.wdw-icon { width: 2.75rem; height: 2.75rem; flex: none; display: inline-flex; align-items: center; justify-content: center; border-radius: .875rem; background: var(--bs-primary-bg-subtle); color: var(--bs-primary); }

/* Component */
.wdw-fs { position: relative; height: 520px; overflow: hidden; display: flex; flex-direction: column; }
.wdw-fs-bar { height: 72px; flex: none; position: relative; z-index: 5; }
.wdw-fs-hero { flex: 1; }
.wdw-burger { position: relative; width: 44px; height: 44px; border: 0; border-radius: 50%; background: var(--bs-tertiary-bg); display: inline-flex; flex-direction: column; align-items: center; justify-content: center; gap: 5px; color: var(--bs-emphasis-color); transition: background .2s; }
.wdw-burger:hover { background: var(--bs-secondary-bg); }
.wdw-burger:focus-visible { outline: 3px solid var(--bs-primary); outline-offset: 2px; }
.wdw-burger span { display: block; width: 18px; height: 2px; border-radius: 2px; background: currentColor; transition: transform .35s cubic-bezier(.4, 0, .2, 1), opacity .2s; }
.wdw-burger[aria-expanded="true"] { background: rgba(255, 255, 255, .16); color: #fff; }
.wdw-burger[aria-expanded="true"]:focus-visible { outline-color: #fff; }
.wdw-burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.wdw-burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.wdw-burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
.wdw-brand { transition: color .3s; }
.wdw-fs.is-open .wdw-brand { color: #fff; }
.wdw-overlay-fs { position: absolute; inset: 0; z-index: 4; display: flex; align-items: center; padding: 72px 2rem 1rem; clip-path: circle(0 at calc(100% - 2.75rem) 2.25rem); visibility: hidden; transition: clip-path .6s cubic-bezier(.65, 0, .35, 1), visibility 0s linear .6s; }
.wdw-fs.is-open .wdw-overlay-fs { clip-path: circle(150% at calc(100% - 2.75rem) 2.25rem); visibility: visible; transition-delay: 0s; }
.wdw-overlay-fs a { display: inline-flex; align-items: baseline; gap: 1rem; padding: .25rem 0; color: #fff; text-decoration: none; font-size: clamp(2rem, 6vw, 3.5rem); font-weight: 800; letter-spacing: -.02em; opacity: 0; transform: translateY(24px); transition: opacity .3s, transform .3s; }
.wdw-fs.is-open .wdw-overlay-fs a { opacity: 1; transform: none; transition: opacity .4s calc(.25s + var(--i) * .07s), transform .4s calc(.25s + var(--i) * .07s); }
.wdw-fs.is-open .wdw-overlay-fs a:hover, .wdw-fs.is-open .wdw-overlay-fs a:focus-visible { opacity: .72; transition-delay: 0s; }
.wdw-overlay-fs a:focus-visible { outline: 3px solid #fff; outline-offset: 4px; border-radius: .5rem; }
.wdw-num { font-size: .8rem; font-weight: 700; letter-spacing: .1em; opacity: .6; }
@media (max-width: 575.98px) { .wdw-fs { height: 560px; } .wdw-overlay-fs { padding-inline: 1.5rem; } }
@media (prefers-reduced-motion: reduce) { .wdw-overlay-fs, .wdw-overlay-fs a, .wdw-burger span { transition: none !important; } }

(function initFullscreenMenu() {
  var root = document.getElementById('wdwFs');
  var btn = document.getElementById('wdwBurger');
  var overlay = document.getElementById('wdwOverlay');
  var hero = document.getElementById('wdwHero');
  if (!root || !btn || !overlay) return;
  var links = overlay.querySelectorAll('a');
  function setOpen(open, focusTarget) {
    root.classList.toggle('is-open', open);
    btn.setAttribute('aria-expanded', open);
    btn.setAttribute('aria-label', open ? 'Close menu' : 'Open menu');
    overlay.inert = !open;
    if (hero) hero.inert = open;
    if (open && focusTarget === 'first' && links[0]) setTimeout(function () { links[0].focus({ preventScroll: true }); }, 350);
    if (!open && focusTarget === 'burger') btn.focus();
  }
  // Starts open so the menu is visible on load; the hero stays inert while it is.
  setOpen(true);
  btn.addEventListener('click', function () {
    var open = btn.getAttribute('aria-expanded') !== 'true';
    setOpen(open, open ? 'first' : null);
  });
  document.addEventListener('keydown', function (e) {
    if (!root.classList.contains('is-open')) return;
    if (e.key === 'Escape') { setOpen(false, 'burger'); return; }
    if (e.key !== 'Tab' || !links.length) return;
    var first = links[0], last = links[links.length - 1];
    var active = document.activeElement;
    if (e.shiftKey && (active === btn || !root.contains(active))) { e.preventDefault(); last.focus(); }
    else if (e.shiftKey && active === first) { e.preventDefault(); btn.focus(); }
    else if (!e.shiftKey && active === last) { e.preventDefault(); btn.focus(); }
    else if (!e.shiftKey && !root.contains(active)) { e.preventDefault(); first.focus(); }
  });
  links.forEach(function (a) {
    a.addEventListener('click', function (e) { e.preventDefault(); setOpen(false, 'burger'); });
  });
})();