@layer elements {

  /* ── NOTEBOOK HEADER ─────────────────────────────────────────────────── */
  .notebook-header {
    padding: 64px 0 40px;
    border-bottom: 1px solid var(--color-rule);
  }

  .notebook-header__label {
    font-family: var(--font-mono);
    font-size: var(--size-xs);
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--color-ink-muted);
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 16px;
  }

  .notebook-header__label::before {
    content: '';
    display: block;
    width: 32px;
    height: 1px;
    background: var(--color-rule);
  }

  .notebook-header__title {
    font-size: var(--size-2xl);
    font-weight: 500;
    letter-spacing: -0.02em;
    line-height: var(--leading-tight);
    margin-bottom: 12px;
  }

  .notebook-header__desc {
    font-size: var(--size-base);
    font-style: italic;
    color: var(--color-ink-mid);
    max-width: 52ch;
  }

  /* ── FILTER STRIP ────────────────────────────────────────────────────── */
  .filter-strip {
    display: flex;
    gap: 2px;
    padding: 28px 0;
    flex-wrap: wrap;
  }

  .filter-btn {
    font-family: var(--font-mono);
    font-size: var(--size-xs);
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--color-ink-muted);
    background: var(--color-block-bg);
    border: none;
    padding: 5px 10px;
    cursor: pointer;
    transition: all 0.12s ease;
  }

  .filter-btn:hover { color: var(--color-ink); }
  .filter-btn.active { background: var(--color-ink); color: var(--color-paper); }

  /* ── YEAR GROUP ──────────────────────────────────────────────────────── */
  .year-group {
    margin-bottom: 48px;
  }

  .year-group__heading {
    font-family: var(--font-mono);
    font-size: var(--size-xs);
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--color-ink-muted);
    padding: 16px 0;
    display: flex;
    align-items: center;
    gap: 12px;
  }

  .year-group__heading::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--color-rule);
  }

  .year-group__entries {
    display: flex;
    flex-direction: column;
    gap: 2px;
  }

  /* ── NOTE ENTRY ──────────────────────────────────────────────────────── */
  .note-entry {
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: baseline;
    gap: 24px;
    padding: 16px 24px;
    background: var(--color-block-bg);
    text-decoration: none;
    color: inherit;
    transition: background 0.12s ease;
  }

  .note-entry:hover { background: var(--color-block-hover); }
  .note-entry:hover .note-entry__arrow { color: var(--color-accent); transform: translateX(3px); }

  .note-entry[hidden] { display: none; }

  .note-entry__title {
    font-family: var(--font-body);
    font-size: var(--size-base);
    color: var(--color-ink);
    margin-bottom: 3px;
    line-height: 1.3;
  }

  .note-entry__date {
    font-family: var(--font-mono);
    font-size: var(--size-xs);
    color: var(--color-ink-muted);
    letter-spacing: 0.06em;
  }

  .note-entry__meta {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
  }

  .note-entry__tag {
    font-family: var(--font-mono);
    font-size: 9px;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--color-ink-muted);
    border: 1px solid var(--color-rule);
    padding: 2px 6px;
  }

  .note-entry__arrow {
    font-family: var(--font-mono);
    font-size: var(--size-xs);
    color: var(--color-rule);
    transition: color 0.12s ease, transform 0.12s ease;
    display: inline-block;
  }

  /* ── RESPONSIVE ──────────────────────────────────────────────────────── */
  @media (max-width: 768px) {
    .note-entry { grid-template-columns: 1fr; }
    .note-entry__meta { display: none; }
  }

}