:root {
  --c-bg: #ffffff;
  --c-fg: #0f172a;
  --c-muted: #475569;
  --c-brand: #0ea5e9;
  --c-bdr: #e2e8f0;
  --c-card: #f8fafc;
  --toc-width: 280px;
  --max-w: 1200px;
  --container: 1200px;
  --content: 780px;
  --brand: #0a66c2;
  --ink: #111;
  --muted: #666;
  --bg: #fff;
  --panel: #fafafa;
  --border: #eee;
  --radius: 12px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, "Noto Sans SC",
    "PingFang SC", sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.75;
  font-size: 16px;
}

/* 移动端字体适配 */
@media (max-width: 768px) {
  body {
    font-size: 14px;
    line-height: 1.6;
  }
}

a {
  color: var(--c-brand);
  text-decoration: none
}

a:hover {
  text-decoration: underline
}

/* 顶部封面 */
header.hero {
  background: linear-gradient(180deg, var(--brand), #0a5ad1);
  color: #fff;
  padding: 20px 16px; /* 移动端减少内边距 */
}

.hero-wrap {
  max-width: var(--container);
  margin: 0 auto;
  display: flex;
  gap: 16px; /* 移动端减小间距 */
  align-items: center;
  flex-wrap: wrap;
}

.hero h1 {
  font-size: 24px; /* 移动端缩小标题 */
  line-height: 1.2;
  margin: 0 0 8px;
}

@media (min-width: 768px) {
  .hero h1 {
    font-size: 32px;
  }
  header.hero {
    padding: 40px 20px;
  }
}

.hero p {
  margin: 0;
  color: #e6f2ff;
  font-size: 14px;
}

.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 16px;
  width: 100%;
}

main {
  display: block; /* 移动端默认单列 */
  width: 100%;
}

@media (min-width: 1024px) {
  main {
    display: grid;
    grid-template-columns: 1fr var(--toc-width);
    gap: 32px
  }
}

article {
  width: 100%;
  padding: 0;
}

.post-title {
  font-size: 28px;
  line-height: 1.2;
  margin: 16px 0
}

@media (min-width: 768px) {
  .post-title {
    font-size: 36px;
  }
}

.meta {
  color: var(--c-muted);
  font-size: 14px
}

.cover {
  margin: 16px 0; /* 移动端减小间距 */
  background: var(--c-card);
  border: 1px solid var(--c-bdr);
  border-radius: 16px;
  overflow: hidden;
  width: 100%;
}

figure {
  margin: 0;
  width: 100%;
}

figure img {
  display: block;
  width: 100%;
  height: auto;
  /* 移动端图片自适应 */
  max-width: 100%;
}

figure figcaption {
  padding: 8px 12px;
  font-size: 12px;
  color: var(--c-muted);
}

/* 移动端目录样式优化 */
.toc-inline {
  margin: 20px 0;
  padding: 16px;
  background: var(--c-card);
  border-radius: 8px;
  border: 1px solid var(--c-bdr);
}

.toc-inline h2 {
  font-size: 18px;
  margin-bottom: 8px;
}

.toc-inline ol {
  padding-left: 20px;
}

.toc-inline li {
  margin: 4px 0;
}

/* 右侧目录浮窗 - 移动端隐藏，大屏显示 */
.toc-card {
  margin-top: 20px;
  border: 1px solid var(--c-bdr);
  border-radius: 16px;
  background: var(--c-card);
  padding: 16px;
}

@media (min-width: 1024px) {
  .toc-card {
    position: sticky;
    top: 90px;
    max-height: 80vh;
    overflow: auto
  }
}

.toc-card h3 {
  margin: 0 0 8px 0;
  font-size: 14px;
  color: var(--c-muted)
}

.toc {
  list-style: none;
  padding-left: 0;
  margin: 0
}

.toc li {
  margin: 6px 0
}

.toc a {
  display: block;
  font-size: 14px;
  line-height: 1.4
}

.toc a.active {
  font-weight: 600
}

.content {
  margin: 16px 0;
  width: 100%;
}

.content h2 {
  margin-top: 24px; /* 移动端减小间距 */
  padding-top: 12px;
  border-top: 1px dashed var(--c-bdr);
  font-size: 20px;
}

@media (min-width: 768px) {
  .content h2 {
    margin-top: 36px;
    font-size: 24px;
  }
}

.content h3 {
  margin-top: 20px;
  font-size: 18px;
}

blockquote {
  margin: 16px 0;
  padding: 12px 16px;
  border-left: 4px solid var(--c-brand);
  background: #f0f9ff;
  border-radius: 8px
}

/* 表格移动端适配 - 横向滚动 */
.table-wrap {
  overflow: auto;
  border: 1px solid var(--c-bdr);
  border-radius: 12px;
  margin: 16px 0;
  width: 100%;
}

table {
  border-collapse: collapse;
  width: 100%;
  font-size: 14px
}

th,
td {
  border-bottom: 1px solid var(--c-bdr);
  padding: 10px 12px;
  text-align: left
}

th {
  background: #f1f5f9
}

/* 行动召唤按钮 - 移动端适配 */
.cta {
  display: flex;
  flex-direction: column; /* 移动端垂直排列 */
  align-items: stretch;
  justify-content: center;
  gap: 16px;
  background: linear-gradient(180deg, #e0f2fe, #f0f9ff);
  border: 1px solid var(--c-bdr);
  border-radius: 16px;
  padding: 20px 16px;
  margin: 24px 0;
}

@media (min-width: 768px) {
  .cta {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    padding: 20px;
  }
}

.btn {
  display: inline-block;
  padding: 12px 20px; /* 移动端加大点击区域 */
  border-radius: 999px;
  border: 1px solid var(--c-brand);
  background: var(--c-brand);
  color: #fff;
  font-weight: 600;
  text-align: center;
  /* 移动端按钮全屏宽 */
  width: 100%;
}

@media (min-width: 768px) {
  .btn {
    width: auto;
    padding: 10px 16px;
  }
}

/* 相关文章网格 - 移动端单列 */
.grid {
  display: grid;
  gap: 16px;
  width: 100%;
}

.grid-2 {
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .grid-2 {
    grid-template-columns: repeat(2, 1fr);
  }
}

.related-card {
  border: 1px solid var(--c-bdr);
  border-radius: 16px;
  padding: 16px;
  background: #fff;
  width: 100%;
}

footer {
  margin-top: 40px;
  padding: 24px 0;
  border-top: 1px solid var(--c-bdr);
  color: var(--c-muted);
  font-size: 14px;
}

.internal-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 12px 0
}

.tag {
  font-size: 12px;
  border: 1px solid var(--c-bdr);
  border-radius: 999px;
  padding: 6px 10px;
  background: #fff
}

strong {
  color: red;
}

.w-100 {
  width: 100%;
}

.img-radius {
  border-radius: 8px;
}

/* FAQ 折叠面板移动端优化 */
details {
  margin: 8px 0;
  padding: 12px;
  background: var(--c-card);
  border-radius: 8px;
  border: 1px solid var(--c-bdr);
}

summary {
  font-weight: 600;
  cursor: pointer;
  user-select: none;
}

details p {
  margin-top: 8px;
  padding-left: 8px;
}

/* 面包屑导航移动端适配 */
.breadcrumb {
  font-size: 14px;
  color: var(--c-muted);
  margin-bottom: 16px;
}
/* 返回顶部按钮 */
.back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--c-brand);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  z-index: 999;
  border: none;
  outline: none;
}
.back-to-top.show {
  opacity: 1;
  visibility: visible;
}
.back-to-top:hover {
  background: #0284c7;
  transform: translateY(-3px);
}