/* =========================================================
   清晨教育 - 知识库栏目页样式（依赖 style.css 的设计变量）
   ========================================================= */

/* ---------- 导航搜索框（与导航链接同一水平线，位于"联系我们"之后） ---------- */
.main-nav { display: flex; align-items: center; gap: 12px; }
.main-nav ul { flex: 1; justify-content: flex-end; }
.nav-search {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  border: 1px solid var(--border);
  border-radius: 999px;
  overflow: hidden;
  background: var(--bg-alt);
  transition: var(--transition);
}
.nav-search:focus-within { border-color: var(--blue); background: var(--white); }
.nav-search input {
  border: none;
  outline: none;
  background: transparent;
  padding: 8px 4px 8px 16px;
  font-size: 14px;
  width: 150px;
  font-family: inherit;
  color: var(--text);
}
.nav-search button {
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 8px 12px 8px 6px;
  font-size: 14px;
}

/* ---------- 栏目 Banner ---------- */
.kb-hero {
  background: linear-gradient(120deg, var(--blue) 0%, var(--blue-dark) 55%, var(--blue-deep) 100%);
  color: var(--white);
  padding: 64px 0 56px;
  text-align: center;
}
.kb-hero h1 { font-size: 38px; letter-spacing: 6px; margin-bottom: 10px; }
.kb-hero p { font-size: 16px; color: rgba(255,255,255,0.82); }

/* ---------- 面包屑 + 工具行 ---------- */
.kb-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
  padding: 22px 0;
  border-bottom: 1px solid var(--border);
}
.breadcrumb ol { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.breadcrumb li { font-size: 14px; color: var(--text-sub); }
.breadcrumb a { color: var(--text-sub); }
.breadcrumb a:hover { color: var(--blue); }
.breadcrumb li[aria-current] { color: var(--blue-deep); font-weight: 600; }

.kb-tools { display: flex; align-items: center; gap: 24px; flex-wrap: wrap; }

/* 最新 | 最热 */
.kb-sort { display: flex; align-items: center; gap: 10px; }
.sort-btn {
  border: none;
  background: none;
  font-size: 15px;
  color: var(--text-sub);
  cursor: pointer;
  padding: 4px 2px;
  font-family: inherit;
  transition: var(--transition);
  position: relative;
}
.sort-btn.active { color: var(--blue); font-weight: 700; }
.sort-btn.active::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -3px;
  height: 2px;
  background: var(--blue);
  border-radius: 2px;
}
.sort-divider { color: var(--border); }

/* 栏目搜索框 */
.kb-search {
  display: flex;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 999px;
  overflow: hidden;
  background: var(--white);
  transition: var(--transition);
}
.kb-search:focus-within { border-color: var(--blue); box-shadow: 0 0 0 3px var(--blue-light); }
.kb-search input {
  border: none;
  outline: none;
  padding: 9px 4px 9px 18px;
  font-size: 14px;
  width: 200px;
  font-family: inherit;
  color: var(--text);
}
.kb-search button {
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 9px 14px 9px 8px;
  font-size: 14px;
}

/* ---------- 主体布局 ---------- */
.kb-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 36px;
  padding-top: 36px;
  padding-bottom: 80px;
  align-items: start;
}

/* ---------- 左侧栏目树 ---------- */
.kb-sidebar {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 18px;
  position: sticky;
  top: 92px;
}

/* 小屏栏目抽屉：桌面端不改变原有侧栏布局 */
.kb-cat-mobile { display: contents; }
.kb-cat-toggle-input,
.kb-cat-toggle,
.kb-cat-backdrop { display: none; }
.sidebar-title {
  font-size: 17px;
  color: var(--blue-deep);
  padding: 0 8px 14px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 10px;
}
.cat-parent {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  border: none;
  background: none;
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  padding: 11px 10px;
  cursor: pointer;
  border-radius: 8px;
  font-family: inherit;
  text-align: left;
  transition: var(--transition);
}
.cat-parent:hover { color: var(--blue); background: var(--bg-alt); }
.cat-arrow { font-size: 11px; color: var(--blue); width: 14px; }
.cat-children {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}
.cat-item.open .cat-children { max-height: 600px; }
.cat-children li a {
  display: block;
  font-size: 14px;
  color: var(--text-sub);
  padding: 9px 10px 9px 32px;
  border-radius: 8px;
  transition: var(--transition);
}
.cat-children li a:hover { color: var(--blue); background: var(--bg-alt); }
/* 选中项加背景色 */
.cat-children li a.active {
  color: var(--blue);
  font-weight: 600;
  background: var(--blue-light);
}

/* ---------- 文章列表 ---------- */
.kb-list { display: flex; flex-direction: column; gap: 22px; }
.kb-item {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 24px;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  transition: var(--transition);
}
.kb-item:hover { box-shadow: var(--shadow-hover); transform: translateY(-3px); }
.kb-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 10px;
  aspect-ratio: 3/2;
}
.kb-item-body { display: flex; flex-direction: column; min-width: 0; }
.kb-item-body h2 { font-size: 19px; line-height: 1.5; margin-bottom: 10px; }
.kb-item-body h2 a { color: var(--blue-deep); }
.kb-item-body h2 a:hover { color: var(--blue); }
.kb-item-body > p {
  font-size: 14px;
  color: var(--text-sub);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: 14px;
  flex: 1;
}
.kb-meta {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  font-size: 13px;
  color: var(--text-sub);
}
.kb-tag {
  background: var(--blue-light);
  color: var(--blue);
  border-radius: 6px;
  padding: 3px 10px;
  font-size: 12px;
  font-weight: 600;
}
.kb-views { color: #9aa9bd; }

.kb-empty {
  text-align: center;
  color: var(--text-sub);
  padding: 60px 0;
  font-size: 15px;
}

/* ---------- 分页 ---------- */
.kb-pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-top: 44px;
}
.kb-pagination a, .kb-pagination span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 38px;
  height: 38px;
  padding: 0 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--white);
  font-size: 14px;
  color: var(--text-sub);
  transition: var(--transition);
}
.kb-pagination a:hover { color: var(--blue); border-color: var(--blue); }
.kb-pagination .page-num.active {
  background: var(--blue);
  border-color: var(--blue);
  color: var(--white);
  font-weight: 700;
}
.kb-pagination .disabled { opacity: 0.45; cursor: not-allowed; }

/* =========================================================
   响应式
   ========================================================= */
@media (max-width: 1024px) {
  .kb-layout { grid-template-columns: 220px 1fr; gap: 24px; }
  .kb-item { grid-template-columns: 200px 1fr; }
  /* 头部空间收窄时保持搜索框与导航同行 */
  .header-inner { gap: 16px; }
  .main-nav a { padding: 8px 10px; font-size: 14px; }
  .nav-search input { width: 110px; }
}

@media (max-width: 768px) {
  /* 移动端：搜索框收入汉堡菜单，位于导航链接下方 */
  .main-nav { top: 100%; flex-direction: column; align-items: stretch; gap: 0; }
  .main-nav ul { justify-content: flex-start; }
  .main-nav.open { max-height: 560px; }
  .nav-search { width: calc(100% - 32px); margin: 0 16px 14px; }
  .nav-search input { flex: 1; width: auto; }
  .kb-hero { padding: 44px 0 38px; }
  .kb-hero h1 { font-size: 28px; letter-spacing: 4px; }
  .kb-toolbar { flex-direction: column; align-items: stretch; gap: 14px; }
  .kb-tools { justify-content: space-between; }
  .kb-search { flex: 1; }
  .kb-search input { width: 100%; }
  .kb-layout { grid-template-columns: minmax(0, 1fr); padding-top: 24px; }
  .kb-list-wrap { min-width: 0; }
  .kb-sidebar { position: static; }
  .kb-item { grid-template-columns: 1fr; gap: 14px; padding: 16px; }
  .kb-thumb img { aspect-ratio: 16/9; height: auto; }

  /* 知识库文章列表：小屏改为两列纵向卡片，减少长列表高度 */
  .kb-list--grid-mobile {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    align-items: stretch;
    gap: 14px;
  }

  .kb-list--grid-mobile .kb-item {
    display: flex;
    flex-direction: column;
    gap: 0;
    min-width: 0;
    padding: 0;
    overflow: hidden;
  }

  .kb-list--grid-mobile .kb-thumb {
    display: block;
  }

  .kb-list--grid-mobile .kb-thumb img {
    width: 100%;
    height: auto;
    aspect-ratio: 4 / 3;
    border-radius: 0;
  }

  .kb-list--grid-mobile .kb-item-body {
    flex: 1;
    padding: 12px 12px 14px;
  }

  .kb-list--grid-mobile .kb-item-body h2 {
    display: -webkit-box;
    -webkit-box-orient: vertical;
    -webkit-line-clamp: 2;
    overflow: hidden;
    overflow-wrap: anywhere;
    margin-bottom: 8px;
    font-size: 15px;
    line-height: 1.45;
  }

  .kb-list--grid-mobile .kb-item-body > p {
    margin-bottom: 10px;
    font-size: 12.5px;
    line-height: 1.6;
  }

  .kb-list--grid-mobile .kb-meta {
    gap: 5px 8px;
    font-size: 11px;
  }

  .kb-list--grid-mobile .kb-tag {
    padding: 2px 6px;
    font-size: 11px;
  }
}

/* 小屏：右侧固定“栏目”按钮 + 右侧分类抽屉 */
@media (max-width: 768px) {
  .kb-cat-mobile {
    display: block;
    height: 0;
  }

  .kb-cat-toggle-input {
    display: block;
    position: fixed;
    width: 1px;
    height: 1px;
    opacity: 0;
    pointer-events: none;
    overflow: hidden;
    clip-path: inset(50%);
  }

  .kb-cat-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    position: fixed;
    right: 0;
    top: 50%;
    z-index: 98;
    transform: translateY(-50%);
    padding: 16px 10px;
    border-radius: 10px 0 0 10px;
    background: var(--blue);
    color: var(--white);
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 4px;
    line-height: 1;
    writing-mode: vertical-rl;
    cursor: pointer;
    box-shadow: 0 6px 18px rgba(11, 99, 229, 0.28);
    user-select: none;
  }

  #kbCatToggle:checked ~ .kb-layout .kb-cat-toggle {
    background: var(--blue-dark);
  }

  #kbCatToggle:focus-visible ~ .kb-layout .kb-cat-toggle {
    outline: 3px solid rgba(11, 99, 229, 0.35);
    outline-offset: 2px;
  }

  /* 小屏默认隐藏排序/搜索；打开栏目抽屉后固定到抽屉顶部 */
  .kb-tools--drawer {
    display: none;
  }

  #kbCatToggle:checked ~ .container .kb-tools--drawer {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
    position: fixed;
    top: 64px;
    right: 46px;
    z-index: 97;
    width: min(78vw, 320px);
    padding: 16px 18px;
    background: var(--white);
    border-left: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    border-radius: 14px 0 0 0;
    box-sizing: border-box;
  }

  #kbCatToggle:checked ~ .container .kb-tools--drawer .kb-search {
    width: 100%;
    display: flex;
  }

  #kbCatToggle:checked ~ .container .kb-tools--drawer .kb-search input {
    flex: 1 1 auto;
    width: auto;
    min-width: 0;
  }

  #kbCatToggle:checked ~ .container .kb-tools--drawer .kb-search button {
    flex: 0 0 auto;
  }

  .kb-cat-backdrop {
    display: block;
    position: fixed;
    inset: 64px 0 0 0;
    z-index: 94;
    background: rgba(10, 37, 64, 0.45);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s ease, visibility 0.25s ease;
  }

  .kb-cat-mobile .kb-sidebar {
    position: fixed;
    top: 64px;
    right: 46px;
    bottom: 0;
    z-index: 95;
    width: min(78vw, 320px);
    max-height: none;
    margin: 0;
    padding: 150px 18px calc(24px + env(safe-area-inset-bottom));
    border-radius: 14px 0 0 0;
    box-shadow: -12px 0 30px rgba(10, 37, 64, 0.18);
    overflow-y: auto;
    transform: translateX(calc(100% + 46px));
    visibility: hidden;
    transition: transform 0.28s ease, visibility 0.28s ease;
    -webkit-overflow-scrolling: touch;
  }

  #kbCatToggle:checked ~ .kb-layout .kb-cat-backdrop {
    opacity: 1;
    visibility: visible;
  }

  #kbCatToggle:checked ~ .kb-layout .kb-sidebar {
    transform: translateX(0);
    visibility: visible;
  }
}

@media (max-width: 480px) {
  .kb-list--grid-mobile {
    gap: 10px;
  }

  .kb-list--grid-mobile .kb-item-body {
    padding: 10px;
  }

  .kb-list--grid-mobile .kb-item-body h2 {
    margin-bottom: 6px;
    font-size: 14px;
    line-height: 1.4;
  }

  .kb-list--grid-mobile .kb-item-body > p {
    margin-bottom: 8px;
    font-size: 12px;
    line-height: 1.55;
  }

  .kb-list--grid-mobile .kb-meta {
    gap: 4px 6px;
    font-size: 11px;
  }
}

/* ---------- CTA 横幅 ---------- */
.cta-band {
  background: linear-gradient(120deg, var(--blue) 0%, var(--blue-dark) 60%, var(--blue-deep) 100%);
  padding: 80px 0;
  text-align: center;
  color: var(--white);
}
.cta-inner h2 { font-size: 34px; margin-bottom: 12px; }
.cta-inner p { font-size: 17px; color: rgba(255,255,255,0.85); margin-bottom: 32px; }
.cta-inner .hero-actions { justify-content: center; margin-bottom: 0; }