Bootstrap 5 Month Pagination with Year Switcher

<section class="wdw-stage">
  <div class="container" style="max-width:960px;min-width:0">
    <div class="wdw-card p-4 p-md-5">
      <div class="d-flex flex-wrap justify-content-between align-items-center gap-3 mb-4">
        <div><span class="wdw-eyebrow">Calendar</span><h2 class="wdw-heading h3 mt-1 mb-0">Browse by month</h2></div>
        <div class="d-flex align-items-center gap-2">
          <button type="button" class="btn btn-outline-secondary rounded-circle p-0" style="width:44px" id="mpPrev" aria-label="Previous month"><svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="m15 6-6 6 6 6"/></svg></button>
          <span class="fw-bold fs-5 text-body-emphasis text-center" style="min-width:4.5rem" id="mpYear">2026</span>
          <button type="button" class="btn btn-outline-secondary rounded-circle p-0" style="width:44px" id="mpNext" aria-label="Next month"><svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="m9 6 6 6-6 6"/></svg></button>
        </div>
      </div>
      <div class="mp p-1 rounded-4 bg-body-tertiary border" role="radiogroup" aria-label="Month" id="mpList"></div>
      <div class="d-flex align-items-center gap-2 mt-4 mb-2"><h3 class="h6 fw-bold mb-0" id="mpOut" role="status" aria-live="polite"></h3><span class="small wdw-muted d-inline-flex align-items-center gap-1 ms-auto"><span class="mp-dot-key" aria-hidden="true"></span>Has events</span></div>
      <ul class="list-group list-group-flush" id="mpEvents"></ul>
    </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 */
.mp { display: grid; grid-template-columns: repeat(12, 1fr); gap: .25rem; }
@media (max-width: 767.98px) { .mp { grid-template-columns: repeat(4, 1fr); } }
.mp .btn { --bs-btn-border-color: transparent; --bs-btn-color: var(--bs-body-color); --bs-btn-hover-color: var(--bs-primary); --bs-btn-hover-bg: var(--bs-primary-bg-subtle); --bs-btn-hover-border-color: transparent; --bs-btn-active-color: #fff; position: relative; padding-inline: 0; border-radius: 50rem; }
[data-bs-theme="dark"] .mp .btn { --bs-btn-active-color: #0f1117; }
.mp .btn-check:checked + .btn { color: var(--bs-btn-active-color); }
.mp .btn-check:focus-visible + .btn { box-shadow: 0 0 0 .25rem var(--bs-focus-ring-color); }
.mp-dot { position: absolute; bottom: 5px; left: 50%; width: 4px; height: 4px; margin-left: -2px; border-radius: 50%; background: currentColor; opacity: 0; }
.mp .has-ev .mp-dot { opacity: .7; }
.mp-dot-key { width: 6px; height: 6px; border-radius: 50%; background: var(--bs-primary); }
.mp-date { width: 3rem; flex: none; }

function initMonthPagination() {
  const list = document.getElementById('mpList');
  if (!list) return;
  const names = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'];
  const full = ['January','February','March','April','May','June','July','August','September','October','November','December'];
  const titles = [['Design review','Team workshop'],['Product launch','Community meetup'],['Customer webinar','Roadmap planning'],['Open office hours','Release party'],['Hackathon','Partner briefing']];
  const times = ['10:00','13:30','16:00'];
  const yearEl = document.getElementById('mpYear');
  const out = document.getElementById('mpOut');
  const evList = document.getElementById('mpEvents');
  const prev = document.getElementById('mpPrev');
  const next = document.getElementById('mpNext');
  const now = new Date();
  const minIdx = (now.getFullYear() - 1) * 12;
  const maxIdx = (now.getFullYear() + 1) * 12 + 11;
  let idx = now.getFullYear() * 12 + now.getMonth();

  const hasEvents = (i) => i % 5 !== 0;
  const eventsFor = (i) => hasEvents(i) ? [0, 1, 2].map((k) => ({
    day: 3 + ((i * 3 + k * 9) % 24),
    title: titles[(i + k) % titles.length][k % 2],
    time: times[(i + k) % 3]
  })).sort((a, b) => a.day - b.day) : [];

  list.innerHTML = names.map((n, m) => '<div><input type="radio" class="btn-check" name="mpMonth" id="mp' + m + '" value="' + m + '" autocomplete="off"><label class="btn btn-outline-primary w-100 fw-semibold" for="mp' + m + '" aria-label="' + full[m] + '">' + n + '<span class="mp-dot" aria-hidden="true"></span></label></div>').join('');
  const radios = list.querySelectorAll('input');
  const labels = list.querySelectorAll('label');

  function update() {
    const year = Math.floor(idx / 12);
    const month = idx % 12;
    yearEl.textContent = year;
    radios.forEach((r, m) => {
      const i = year * 12 + m;
      r.checked = m === month;
      r.disabled = i < minIdx || i > maxIdx;
      labels[m].classList.toggle('has-ev', hasEvents(i));
    });
    prev.disabled = idx <= minIdx;
    next.disabled = idx >= maxIdx;
    out.textContent = 'Events in ' + full[month] + ' ' + year;
    const evs = eventsFor(idx);
    evList.innerHTML = evs.length ? evs.map((e) => '<li class="list-group-item bg-transparent px-0 d-flex align-items-center gap-3"><span class="mp-date wdw-icon text-center fw-bold" style="width:3rem">' + e.day + '</span><span class="fw-semibold">' + e.title + '</span><span class="ms-auto small wdw-muted">' + names[month] + ' ' + e.day + ', ' + e.time + '</span></li>').join('') : '<li class="list-group-item bg-transparent px-0 wdw-muted">No events this month.</li>';
  }

  radios.forEach((r) => r.addEventListener('change', () => { idx = Math.floor(idx / 12) * 12 + Number(r.value); update(); }));
  prev.addEventListener('click', () => { if (idx > minIdx) { idx--; update(); } });
  next.addEventListener('click', () => { if (idx < maxIdx) { idx++; update(); } });
  update();
}
initMonthPagination();