/* ==========================================================================
   Rain · 专栏页样式
   --------------------------------------------------------------------------
   01. 面包屑
   02. 专栏头部（英文名 / 标题 / 主线标记 / 定位描述）
   03. 内容区块（学习要点 / 关联节点）
   04. 底部操作与空状态
   ========================================================================== */

/* ==========================================================================
   01. 面包屑
   ========================================================================== */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.82rem;
  color: var(--ink-mute);
}

.breadcrumb a {
  color: var(--ink-mute);
  text-decoration: none;
  transition: color 0.25s;
}

.breadcrumb a:hover {
  color: var(--blue);
}

.breadcrumb-sep {
  opacity: 0.55;
}

#crumbCurrent {
  color: var(--ink);
  font-weight: 600;
}

/* ==========================================================================
   02. 专栏头部
   ========================================================================== */
.topic {
  max-width: 46rem;
  margin-top: 1.6rem;
}

.topic-alias {
  font-family: 'Baloo 2', 'Noto Sans SC', sans-serif;
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--blue);
}

.topic-title {
  margin-top: 0.5rem;
  font-size: clamp(1.7rem, 1.3rem + 1.6vw, 2.3rem);
  font-weight: 700; /* Tailwind preflight 会把标题字重重置为 inherit */
  line-height: 1.3;
  letter-spacing: -0.02em;
}

.topic-badge {
  display: inline-block;
  margin-top: 0.8rem;
  padding: 0.22rem 0.7rem;
  border-radius: 999px;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--blue);
  background: var(--blue-soft);
}

html.dark .topic-badge {
  color: #93c5fd;
}

.topic-summary {
  margin-top: 0.9rem;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--ink-soft);
}

/* ==========================================================================
   03. 内容区块
   ========================================================================== */
.topic-block {
  margin-top: 2.2rem;
  padding: 1.5rem 1.6rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  box-shadow: var(--shadow-sm);
}

.topic-block__title {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  margin-bottom: 1.1rem;
  font-size: 1.02rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

/* 标题前的渐变竖条 */
.topic-block__title::before {
  content: '';
  width: 4px;
  height: 16px;
  border-radius: 999px;
  background: linear-gradient(var(--blue), var(--indigo));
}

/* 标题右侧的数量胶囊（如「文章列表 1」） */
.topic-block__count {
  padding: 0.1rem 0.5rem;
  border-radius: 999px;
  background: var(--surface-2);
  font-family: 'Baloo 2', sans-serif;
  font-size: 0.76rem;
  font-weight: 700;
  color: var(--ink-mute);
}

/* 该专栏暂无文章时的占位 */
.post-empty {
  padding: 1.5rem 1.2rem;
  border-radius: var(--r-lg);
  border: 1px dashed var(--line);
  background: var(--surface-2);
  font-size: 0.88rem;
  color: var(--ink-mute);
  text-align: center;
}

/* —— 专栏下的文章列表 —— */
.post-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.post-item + .post-item {
  margin-top: 0.85rem;
}

.post-item a {
  display: flex;
  align-items: flex-start;
  gap: 0.95rem;
  padding: 1rem 1.1rem;
  border-radius: var(--r-lg);
  border: 1px solid var(--line);
  background: var(--surface-2);
  text-decoration: none;
  transition: transform 0.3s var(--ease-pop), border-color 0.25s, box-shadow 0.3s, background 0.25s;
}

.post-item a:hover,
.post-item a:focus-visible {
  transform: translateY(-3px);
  border-color: var(--blue-soft);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.post-item__index {
  flex: none;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--blue-soft), var(--indigo-soft));
  font-family: 'Baloo 2', sans-serif;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--blue);
}

html.dark .post-item__index {
  color: #93c5fd;
}

.post-item__body {
  flex: 1;
  min-width: 0;
}

.post-item__title {
  display: block;
  font-size: 0.98rem;
  font-weight: 700;
  line-height: 1.5;
  color: var(--ink);
  transition: color 0.25s;
}

.post-item a:hover .post-item__title {
  color: var(--blue);
}

.post-item__summary {
  display: block;
  margin-top: 0.35rem;
  font-size: 0.85rem;
  line-height: 1.7;
  color: var(--ink-mute);
}

.post-item__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem;
  margin-top: 0.55rem;
  font-size: 0.74rem;
  color: var(--ink-mute);
}

.post-item__tags {
  color: var(--blue);
  font-weight: 600;
}

.post-item__arrow {
  flex: none;
  align-self: center;
  font-weight: 700;
  color: var(--blue);
  transition: transform 0.3s var(--ease-pop);
}

.post-item a:hover .post-item__arrow {
  transform: translateX(4px);
}

/* —— 学习要点 —— */
.topic-points {
  counter-reset: point;
  margin: 0;
  padding: 0;
  list-style: none;
}

.topic-points li {
  position: relative;
  padding-left: 2.3rem;
  margin-bottom: 0.95rem;
  font-size: 0.93rem;
  line-height: 1.75;
  color: var(--ink-soft);
}

.topic-points li:last-child {
  margin-bottom: 0;
}

.topic-points li::before {
  counter-increment: point;
  content: counter(point);
  position: absolute;
  left: 0;
  top: 0.15rem;
  display: grid;
  place-items: center;
  width: 1.55rem;
  height: 1.55rem;
  border-radius: 50%;
  font-family: 'Baloo 2', sans-serif;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--blue);
  background: var(--blue-soft);
}

html.dark .topic-points li::before {
  color: #93c5fd;
}

/* —— 关联节点 —— */
.related-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 0.85rem;
}

.related-group:last-child {
  margin-bottom: 0;
}

.related-label {
  min-width: 2.4rem;
  font-size: 0.74rem;
  font-weight: 600;
  color: var(--ink-mute);
}

.related-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.related-chip {
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--surface-2);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--ink-soft);
  text-decoration: none;
  transition: transform 0.25s var(--ease-pop), color 0.25s, border-color 0.25s, background 0.25s;
}

.related-chip:hover,
.related-chip:focus-visible {
  transform: translateY(-2px);
  color: #fff;
  border-color: transparent;
  background: linear-gradient(135deg, var(--blue), var(--indigo));
}

/* 重点节点的胶囊加一层描边提示 */
.related-chip.is-key {
  border-color: var(--blue-soft);
}

/* ==========================================================================
   04. 配套教程入口 / 底部操作与空状态
   ========================================================================== */
.topic-tutorial {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin-top: 2.2rem;
  padding: 1.1rem 1.4rem;
  border-radius: var(--r-lg);
  border: 1px solid var(--blue-soft);
  background: linear-gradient(135deg, var(--blue-soft), var(--surface) 72%);
  text-decoration: none;
  transition: transform 0.3s var(--ease-pop), box-shadow 0.3s, border-color 0.3s;
}

html.dark .topic-tutorial {
  background: linear-gradient(135deg, var(--blue-soft), var(--surface) 72%);
}

.topic-tutorial:hover,
.topic-tutorial:focus-visible {
  transform: translateY(-3px);
  border-color: var(--blue);
  box-shadow: var(--shadow);
}

.topic-tutorial__tag {
  flex: none;
  padding: 0.24rem 0.65rem;
  border-radius: 999px;
  font-size: 0.7rem;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--blue), var(--indigo));
}

.topic-tutorial__title {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--ink);
}

.topic-tutorial__arrow {
  margin-left: auto;
  font-weight: 700;
  color: var(--blue);
  transition: transform 0.3s var(--ease-pop);
}

.topic-tutorial:hover .topic-tutorial__arrow {
  transform: translateX(4px);
}

.topic-actions {
  margin-top: 2.2rem;
}

.topic-fallback {
  padding: 1.5rem;
  border-radius: var(--r-lg);
  border: 1px dashed var(--blue-soft);
  background: var(--surface);
  color: var(--ink-soft);
}

.topic-fallback a {
  color: var(--blue);
}