body {
  font-family: system-ui, sans-serif;
  background-color: #f8f9fa;
}
.sidebar {
  position: fixed;
  top: 56px;
  left: 0;
  width: 250px;
  height: calc(100vh - 56px);
  overflow-y: auto;
  background-color: #fff;
  border-right: 1px solid #dee2e6;
  z-index: 1000;
}
.sidebar .nav-link {
  color: #333;
  display: flex;
  align-items: center;
  gap: 10px;
}
.sidebar .nav-link:hover {
  background-color: #f1f1f1;
}
.nav-link.active {
  background-color: #e9ecef;
  font-weight: bold;
  border-radius: 6px;
}
.nav-section-title {
  font-size: 0.8rem;
  color: #888;
  text-transform: uppercase;
  padding: 0.75rem 1rem 0.25rem;
}
.nav-icon-btn {
  background-color: #f1f1f1;
  border-radius: 20%;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #333;
  font-size: 1.2rem;
  text-decoration: none;
  transition: all 0.3s ease;
}
.nav-icon-btn:hover {
  background-color: #e0e0e0;
  color: #dc3545;
}
.icon-group {
  display: flex;
  align-items: center;
  flex-wrap: nowrap;
  gap: 0.5rem;
  overflow-x: auto;
}
.icon-group a {
  flex-shrink: 0;
}
@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    left: -250px;
    top: 56px;
    width: 250px;
    transition: left 0.3s;
    z-index: 1010;
  }
  .sidebar.show {
    left: 0;
  }
  .overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    z-index: 1000;
  }
}
@media (min-width: 768px) {
  .container {
    margin-left: 260px;
  }
}
@media (min-width: 1080px) {
  .search-input {
    width: 400px;
  }
}
@media (min-width: 1810px) {
  .d-xxxl-block {
    display: flex !important;
  }
  .search-input {
    width: 800px;
  }
}
.sidebar-right {
  position: fixed;
  top: 56px; /* 和 header 对齐 */
  right: 0;
  height: calc(100vh - 56px);
  overflow-y: auto;
  background-color: #fff;
  border-left: 1px solid #dee2e6;
  z-index: 1000;
}
.quickie-wrapper:focus-within .quickie-hint {
  display: block !important;
}
.bold-first-sentence strong {
  font-weight: bold;
}
.breathing-btn {
  animation: breathing 2s ease-in-out infinite;
  box-shadow: 0 0 0 rgba(13, 110, 253, 0.5);
  transition: transform 0.3s ease-in-out, box-shadow 0.3s ease-in-out;
}

@keyframes breathing {
  0% {
    transform: scale(1);
    box-shadow: 0 0 0 0 rgba(204, 204, 204, 0.5);
  }
  50% {
    transform: scale(1.05);
    box-shadow: 0 0 15px 6px  rgba(204, 204, 204, 0.4);
  }
  100% {
    transform: scale(1);
    box-shadow: 0 0 0 0 rgba(204, 204, 204, 0.5);
  }
}

/* ---------- 单页排版 ---------- */
.single-page {
  overflow: hidden;
}
.single-page .card-body {
  padding: 2rem 2.25rem;
}
.single-page-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: #1a1a1a;
  line-height: 1.4;
  padding-bottom: 0.8rem;
  margin-bottom: 1.6rem;
  border-bottom: 1px solid #e9ecef;
  position: relative;
}
.single-page-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 56px;
  height: 3px;
  border-radius: 3px;
  background-color: #0d6efd;
}

/* 正文排版 */
.single-content {
  color: #2b2b2b;
  font-size: 0.975rem;
  line-height: 1.85;
}
.single-content > :last-child {
  margin-bottom: 0;
}
.single-content p {
  margin-bottom: 1.15rem;
}
.single-content h2,
.single-content h3,
.single-content h4,
.single-content h5 {
  color: #1a1a1a;
  font-weight: 700;
  line-height: 1.4;
  margin-top: 1.75rem;
  margin-bottom: 0.85rem;
}
.single-content h2 {
  font-size: 1.4rem;
  padding-bottom: 0.45rem;
  border-bottom: 1px dashed #dee2e6;
}
.single-content h3 {
  font-size: 1.22rem;
}
.single-content h4 {
  font-size: 1.08rem;
}
.single-content ul,
.single-content ol {
  padding-left: 1.35rem;
  margin-bottom: 1.15rem;
}
.single-content li {
  margin-bottom: 0.4rem;
}
.single-content ul li::marker {
  color: #0d6efd;
}
.single-content ol li::marker {
  color: #6c757d;
  font-weight: 600;
}
.single-content strong {
  font-weight: 600;
  color: #0f1114;
}
.single-content a {
  color: #0d6efd;
  text-decoration: none;
}
.single-content a:hover {
  text-decoration: underline;
}
.single-content blockquote {
  margin: 1.25rem 0;
  padding: 0.9rem 1.25rem;
  border-left: 4px solid #0d6efd;
  border-radius: 0 0.375rem 0.375rem 0;
  background-color: #f8f9fa;
  color: #495057;
}
.single-content blockquote p:last-child {
  margin-bottom: 0;
}
.single-content img {
  max-width: 100%;
  height: auto;
  border-radius: 0.5rem;
  margin: 0.75rem 0;
}
.single-content code {
  background-color: #f1f3f5;
  border-radius: 0.25rem;
  padding: 0.15rem 0.4rem;
  font-size: 0.875em;
  color: #d63384;
}
.single-content pre {
  background-color: #212529;
  color: #f8f9fa;
  border-radius: 0.5rem;
  padding: 1rem 1.25rem;
  overflow-x: auto;
  margin-bottom: 1.15rem;
}
.single-content pre code {
  background: none;
  color: inherit;
  padding: 0;
  font-size: 0.9rem;
}
.single-content hr {
  margin: 1.5rem 0;
  border-color: #e9ecef;
  opacity: 1;
}
.single-content table {
  width: 100%;
  margin-bottom: 1.15rem;
  border-collapse: collapse;
}
.single-content th,
.single-content td {
  border: 1px solid #dee2e6;
  padding: 0.5rem 0.75rem;
}
.single-content th {
  background-color: #f8f9fa;
}