Bootstrap 5 Custom Radio Buttons with Hop Animation

<section class="wdw-stage">
  <div class="container" style="max-width: 540px;">
    <form class="wdw-card p-4 p-md-5" id="hop">
      <span class="wdw-eyebrow">Question 1 of 3</span>
      <h2 class="wdw-heading h3 mb-1">Pick your answer</h2>
      <p class="wdw-muted mb-4">Choose one option. The marker hops into place.</p>
      <fieldset class="d-grid gap-3 border-0 p-0 m-0">
        <legend class="visually-hidden">Answer</legend>
        <div>
          <input class="btn-check" type="radio" name="hop" id="hop-a" value="A" checked>
          <label class="btn btn-outline-primary text-start d-flex align-items-center gap-3 hop-label" for="hop-a"><span class="hop-dot" aria-hidden="true"></span><span class="hop-letter">A</span><span class="hop-text flex-grow-1">Design the interface first</span><span class="hop-check" aria-hidden="true"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"><path d="M5 12.5l4.5 4.5L19 7.5"/></svg></span></label>
        </div>
        <div>
          <input class="btn-check" type="radio" name="hop" id="hop-b" value="B">
          <label class="btn btn-outline-primary text-start d-flex align-items-center gap-3 hop-label" for="hop-b"><span class="hop-dot" aria-hidden="true"></span><span class="hop-letter">B</span><span class="hop-text flex-grow-1">Prototype in code straight away</span><span class="hop-check" aria-hidden="true"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"><path d="M5 12.5l4.5 4.5L19 7.5"/></svg></span></label>
        </div>
        <div>
          <input class="btn-check" type="radio" name="hop" id="hop-c" value="C">
          <label class="btn btn-outline-primary text-start d-flex align-items-center gap-3 hop-label" for="hop-c"><span class="hop-dot" aria-hidden="true"></span><span class="hop-letter">C</span><span class="hop-text flex-grow-1">Write the content outline</span><span class="hop-check" aria-hidden="true"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"><path d="M5 12.5l4.5 4.5L19 7.5"/></svg></span></label>
        </div>
      </fieldset>
      <div class="d-flex align-items-center justify-content-between gap-3 mt-4">
        <p class="small wdw-muted mb-0" id="hop-out" aria-live="polite">Step 1 of 3</p>
        <button type="submit" class="btn btn-primary rounded-pill px-4" id="hop-next">Continue</button>
      </div>
    </form>
  </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 */
#hop .hop-label { --bs-btn-color: var(--bs-emphasis-color); --bs-btn-border-color: var(--bs-border-color); --bs-btn-hover-bg: var(--bs-tertiary-bg); --bs-btn-hover-color: var(--bs-emphasis-color); --bs-btn-hover-border-color: var(--bs-primary-border-subtle); --bs-btn-border-radius: 1rem; padding: 1.125rem 1.25rem; min-height: 68px; font-size: 1.0625rem; font-weight: 600; }
#hop .btn-check:checked + .hop-label { background: var(--bs-primary-bg-subtle); color: var(--bs-emphasis-color); border-color: var(--bs-primary); box-shadow: 0 0 0 .25rem var(--bs-focus-ring-color); }
#hop .btn-check:focus-visible + .hop-label { box-shadow: 0 0 0 .3rem var(--bs-focus-ring-color); }
#hop .hop-dot { position: relative; flex: none; width: 2rem; height: 2rem; border-radius: 50%; border: 2px solid var(--bs-secondary-color); }
#hop .hop-dot::after { content: ""; position: absolute; inset: 5px; border-radius: 50%; background: var(--bs-primary); transform: scale(0); }
#hop .btn-check:checked + .hop-label .hop-dot { border-color: var(--bs-primary); animation: hop-jump .5s cubic-bezier(.3,.7,.4,1); }
#hop .btn-check:checked + .hop-label .hop-dot::after { transform: scale(1); animation: hop-pop .4s .1s cubic-bezier(.3,1.6,.5,1) backwards; }
#hop .hop-letter { flex: none; width: 1.25rem; font-weight: 800; color: var(--bs-secondary-color); }
#hop .btn-check:checked + .hop-label .hop-letter { color: var(--bs-primary); }
#hop .hop-check { flex: none; width: 1.75rem; height: 1.75rem; border-radius: 50%; display: inline-flex; align-items: center; justify-content: center; background: var(--bs-primary); color: var(--bs-body-bg); opacity: 0; transform: scale(.4); transition: opacity .2s, transform .25s cubic-bezier(.3,1.6,.5,1); }
#hop .btn-check:checked + .hop-label .hop-check { opacity: 1; transform: scale(1); }
@keyframes hop-jump { 0% { transform: translateY(0) scale(1); } 35% { transform: translateY(-10px) scale(.92, 1.1); } 70% { transform: translateY(0) scale(1.1, .88); } 100% { transform: translateY(0) scale(1); } }
@keyframes hop-pop { from { transform: scale(0); } to { transform: scale(1); } }
@media (prefers-reduced-motion: reduce) { #hop .hop-dot, #hop .hop-dot::after, #hop .hop-check { animation: none !important; transition: none; } }

(function () {
  function initHopRadios() {
    var form = document.getElementById('hop');
    if (!form) return;
    var out = form.querySelector('#hop-out');
    form.addEventListener('submit', function (e) {
      e.preventDefault();
      var sel = form.querySelector('input[name="hop"]:checked');
      if (sel && out) out.textContent = 'Answer ' + sel.value + ' saved';
    });
    form.addEventListener('change', function () { if (out) out.textContent = 'Step 1 of 3'; });
  }
  initHopRadios();
})();