#archive-filter {
  border: 1px solid #ddd;
  border-radius: 8px;
  padding: 8px;
  background: #fff;
  font-family: inherit;
}

.year-item {
  margin-bottom: 6px;
  border-bottom: 1px solid #f1f1f1;
}

.year-header {
  font-weight: bold;
  cursor: pointer;
  padding: 6px 10px;
  background: #f8f8f8;
  border-radius: 4px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.2s;
}
.year-header:hover {
  background: #e8e8e8;
}

.year-header .arrow {
  font-size: 0.8em;
  transition: transform 0.2s;
}

.year-header.active .arrow {
  transform: rotate(180deg);
}

.month-list {
  margin-top: 5px;
  padding-left: 15px;
}

.month-item {
  padding: 4px 8px;
  cursor: pointer;
  border-radius: 3px;
  margin: 2px 0;
  transition: background 0.2s;
}
.month-item:hover {
  background: #f0f0f0;
}
.month-item.active {
  background: #0073aa;
  color: white;
  font-weight: bold;
}

.archive-posts {
  margin-top: 10px;
  list-style: none;
  padding-left: 0;
}
.archive-posts li {
  margin: 3px 0;
}
.archive-posts a {
  text-decoration: none;
  color: #0073aa;
}
.archive-posts a:hover {
  text-decoration: underline;
}