/* ==========================================================================
   base — 基础变量、重置、全局排版
   ========================================================================== */

:root {
  --color-text: #1a1a1a;
  --color-bg: #ffffff;
  --color-accent: #1e3a8a;
  --color-accent-light: #2d4db3;
  --color-bg-soft: #f3f4f6;
  --color-muted: #6b7280;
  --color-border: #e5e7eb;
  --color-white: #ffffff;

  --font-sans: Arial, Helvetica, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-serif: Georgia, "Times New Roman", "Songti SC", serif;

  --container-width: 1200px;
  --container-padding: 24px;
  --radius: 8px;
  --radius-sm: 4px;

  --header-height: 72px;
  --transition: 0.2s ease;
}

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-accent-light);
}

ul,
ol {
  list-style: none;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-sans);
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-text);
}

h1 {
  font-size: 32px;
}

h2 {
  font-size: 24px;
}

h3 {
  font-size: 20px;
}

p {
  margin-bottom: 16px;
}

time {
  color: var(--color-muted);
  font-size: 14px;
}

/* ==========================================================================
   layout — 全站布局骨架、容器、页头、页脚
   ========================================================================== */

.site-header {
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
  height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
  flex-shrink: 0;
}

.brand-name {
  font-size: 20px;
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 0.02em;
}

.brand-tagline {
  font-size: 12px;
  color: var(--color-muted);
  margin-top: 2px;
}

.site-nav {
  margin-left: auto;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-list li a {
  display: block;
  padding: 8px 16px;
  font-size: 15px;
  font-weight: 500;
  color: var(--color-text);
  border-radius: var(--radius-sm);
  transition: background-color var(--transition), color var(--transition);
}

.nav-list li a:hover {
  color: var(--color-accent);
  background-color: var(--color-bg-soft);
}

.nav-list li a.is-current {
  color: var(--color-accent);
  background-color: rgba(30, 58, 138, 0.08);
  font-weight: 700;
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 10px;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  align-items: center;
  border-radius: var(--radius-sm);
}

.nav-toggle:hover {
  background-color: var(--color-bg-soft);
}

.nav-toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 1px;
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.site-main {
  flex: 1;
  width: 100%;
}

.site-footer {
  background-color: var(--color-bg-soft);
  border-top: 1px solid var(--color-border);
  margin-top: 64px;
}

.footer-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 48px var(--container-padding) 24px;
}

.footer-brand {
  margin-bottom: 32px;
}

.footer-slogan {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
}

.footer-desc {
  font-size: 14px;
  color: var(--color-muted);
  max-width: 480px;
  margin-bottom: 0;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  border-top: 1px solid var(--color-border);
  padding-top: 32px;
}

.footer-group h4 {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--color-text);
}

.footer-group ul li {
  margin-bottom: 10px;
}

.footer-group ul li a {
  font-size: 14px;
  color: var(--color-muted);
  transition: color var(--transition);
}

.footer-group ul li a:hover {
  color: var(--color-accent);
}

.footer-bottom {
  border-top: 1px solid var(--color-border);
  margin-top: 32px;
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-bottom p {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 0;
}

.footer-meta {
  font-size: 13px;
  color: var(--color-muted);
}

/* ==========================================================================
   components — 通用组件：面包屑、页面标题、卡片、按钮、标签、侧栏
   ========================================================================== */

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--color-muted);
  margin-bottom: 24px;
  flex-wrap: wrap;
}

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

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

.breadcrumb-sep {
  color: var(--color-muted);
  font-size: 12px;
}

.breadcrumb-current {
  color: var(--color-text);
  font-weight: 500;
}

.page-header {
  margin-bottom: 40px;
}

.page-title {
  font-size: 32px;
  color: var(--color-text);
  margin-bottom: 12px;
}

.page-description {
  font-size: 16px;
  color: var(--color-muted);
  max-width: 720px;
  line-height: 1.7;
}

.section-title {
  font-size: 24px;
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-accent);
  display: inline-block;
}

.btn-primary,
.btn-secondary {
  display: inline-block;
  padding: 12px 28px;
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background-color var(--transition), box-shadow var(--transition);
  border: none;
}

.btn-primary {
  background-color: var(--color-accent);
  color: var(--color-white);
}

.btn-primary:hover {
  background-color: var(--color-accent-light);
  color: var(--color-white);
  box-shadow: 0 4px 12px rgba(30, 58, 138, 0.2);
}

.btn-secondary {
  background-color: transparent;
  color: var(--color-accent);
  border: 1px solid var(--color-accent);
}

.btn-secondary:hover {
  background-color: rgba(30, 58, 138, 0.08);
  color: var(--color-accent);
  box-shadow: 0 2px 8px rgba(30, 58, 138, 0.12);
}

/* 频道标签 */
.channel-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.channel-tag {
  display: inline-block;
  padding: 10px 20px;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text);
  background-color: var(--color-bg-soft);
  border-radius: 999px;
  transition: background-color var(--transition), color var(--transition);
  border: 1px solid transparent;
}

.channel-tag:hover {
  background-color: var(--color-accent);
  color: var(--color-white);
}

/* 文章卡片 */
.latest-item {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 24px;
  padding: 20px 0;
  border-bottom: 1px solid var(--color-border);
}

.latest-text {
  flex: 1;
  min-width: 0;
}

.latest-text h3 {
  font-size: 18px;
  margin-bottom: 8px;
}

.latest-text h3 a {
  color: var(--color-text);
  transition: color var(--transition);
}

.latest-text h3 a:hover {
  color: var(--color-accent);
}

.latest-summary {
  font-family: var(--font-serif);
  font-size: 15px;
  color: var(--color-muted);
  line-height: 1.7;
  margin-bottom: 8px;
}

.latest-date {
  font-size: 13px;
  color: var(--color-muted);
}

/* 专题卡片 */
.topic-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.topic-card {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: box-shadow var(--transition), transform var(--transition);
}

.topic-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
  transform: translateY(-2px);
}

.topic-card img {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.topic-card-content,
.topic-content {
  padding: 20px;
}

.topic-card-content h3,
.topic-content h3 {
  font-size: 18px;
  margin-bottom: 8px;
}

.topic-card-content h3 a,
.topic-content h3 a {
  color: var(--color-text);
}

.topic-card-content h3 a:hover,
.topic-content h3 a:hover {
  color: var(--color-accent);
}

.topic-card-content p,
.topic-content p {
  font-family: var(--font-serif);
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  margin-bottom: 0;
}

/* 编辑推荐条目 */
.editor-picks-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.editor-pick-item {
  padding: 20px 24px;
  background-color: var(--color-bg-soft);
  border-left: 4px solid var(--color-accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  transition: background-color var(--transition);
}

.editor-pick-item:hover {
  background-color: #e9ebf0;
}

.editor-pick-item h3 {
  font-size: 16px;
  margin-bottom: 6px;
}

.editor-pick-item h3 a {
  color: var(--color-text);
}

.editor-pick-item h3 a:hover {
  color: var(--color-accent);
}

.pick-reason {
  font-size: 14px;
  color: var(--color-muted);
  margin-bottom: 0;
  line-height: 1.6;
}

/* 侧栏通用 */
.sidebar {
  min-width: 0;
}

.sidebar-inner {
  background-color: var(--color-bg-soft);
  border-radius: var(--radius);
  padding: 24px;
}

.sidebar-title {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--color-accent);
}

.sidebar-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.sidebar-list li {
  padding: 8px 0;
  border-bottom: 1px solid var(--color-border);
}

.sidebar-list li:last-child {
  border-bottom: none;
}

.sidebar-list li a {
  font-size: 14px;
  color: var(--color-text);
  line-height: 1.5;
  display: block;
}

.sidebar-list li a:hover {
  color: var(--color-accent);
}

.sidebar-list li p {
  font-size: 13px;
  color: var(--color-muted);
  margin-top: 4px;
  margin-bottom: 0;
}

/* 文本链接 */
.text-link {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--color-accent);
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
}

.text-link:hover {
  border-bottom-color: var(--color-accent);
}

/* ==========================================================================
   pages — 首页及各内页业务模块
   ========================================================================== */

/* ---------- 首页 ---------- */

.home-main {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.hero-section {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
  padding: 64px 0;
}

.hero-content {
  min-width: 0;
}

.hero-title {
  font-size: 32px;
  line-height: 1.35;
  margin-bottom: 20px;
}

.hero-lead {
  font-family: var(--font-serif);
  font-size: 18px;
  line-height: 1.8;
  color: var(--color-muted);
  margin-bottom: 32px;
}

.hero-cta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.hero-media {
  min-width: 0;
}

.hero-media img {
  width: 100%;
  height: 320px;
  object-fit: cover;
  border-radius: var(--radius);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
}

.channel-nav-section,
.latest-list-section,
.topic-cards-section,
.editor-picks-section,
.source-info-section {
  padding: 40px 0;
  border-top: 1px solid var(--color-border);
}

.source-info-section {
  border-bottom: 1px solid var(--color-border);
}

.source-info-section p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  max-width: 720px;
}

/* ---------- 频道分类页 ---------- */

.inner-main {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 32px var(--container-padding) 0;
  flex: 1;
  width: 100%;
}

.page-layout {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 40px;
  align-items: start;
}

.sidebar-left .page-layout {
  grid-template-columns: 320px 1fr;
}

.main-content {
  min-width: 0;
}

.channel-sidebar {
  background-color: var(--color-bg-soft);
  border-radius: var(--radius);
  padding: 24px;
  position: sticky;
  top: calc(var(--header-height) + 24px);
}

.channel-sidebar h2 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--color-accent);
}

.channel-nav-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-bottom: 20px;
}

.channel-nav-list li a {
  display: block;
  padding: 10px 14px;
  font-size: 14px;
  color: var(--color-text);
  border-radius: var(--radius-sm);
  transition: background-color var(--transition), color var(--transition);
}

.channel-nav-list li a:hover {
  background-color: var(--color-accent);
  color: var(--color-white);
}

.sidebar-note {
  font-size: 13px;
  color: var(--color-muted);
  line-height: 1.6;
  margin-bottom: 0;
  border-top: 1px solid var(--color-border);
  padding-top: 16px;
}

.channel-content h2 {
  font-size: 24px;
  margin-bottom: 24px;
}

.channel-item {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 24px;
  align-items: center;
  padding: 24px 0;
  border-bottom: 1px solid var(--color-border);
}

.channel-item:last-child {
  border-bottom: none;
}

.channel-text {
  min-width: 0;
}

.channel-text h3 {
  font-size: 20px;
  margin-bottom: 12px;
}

.channel-text p {
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-muted);
  margin-bottom: 12px;
}

.channel-text a {
  font-size: 14px;
  font-weight: 600;
}

.channel-figure {
  min-width: 0;
}

.channel-figure img {
  width: 100%;
  height: 160px;
  object-fit: cover;
  border-radius: var(--radius);
}

.channel-note {
  margin-top: 48px;
  padding: 32px 0;
  border-top: 1px solid var(--color-border);
}

.channel-note h2 {
  font-size: 20px;
  margin-bottom: 16px;
}

.channel-note p {
  font-size: 15px;
  color: var(--color-muted);
  line-height: 1.7;
  max-width: 720px;
}

/* ---------- 内容专题页 ---------- */

.topic-grid {
  margin-bottom: 48px;
}

.topic-grid .topic-cards {
  grid-template-columns: repeat(2, 1fr);
}

.topic-media img {
  width: 100%;
  height: 180px;
  object-fit: cover;
}

.topic-excerpt {
  font-size: 14px;
  color: var(--color-muted);
  margin-bottom: 12px;
}

.topic-link {
  font-size: 14px;
  font-weight: 600;
}

.topic-intro {
  padding: 40px 0;
  border-top: 1px solid var(--color-border);
}

.intro-layout {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 40px;
  align-items: start;
}

.intro-text {
  min-width: 0;
}

.intro-text p {
  font-size: 15px;
  line-height: 1.8;
  color: var(--color-muted);
  margin-bottom: 16px;
}

.intro-aside {
  background-color: var(--color-bg-soft);
  border-radius: var(--radius);
  padding: 24px;
}

.intro-aside h3 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--color-accent);
}

.intro-aside ul {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 16px;
}

.intro-aside ul li {
  font-size: 14px;
  color: var(--color-muted);
  padding-left: 16px;
  position: relative;
  line-height: 1.5;
}

.intro-aside ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  background-color: var(--color-accent);
  border-radius: 50%;
}

/* ---------- 阅读指南页 ---------- */

.guide-section {
  margin-bottom: 48px;
}

.guide-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.guide-card {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: box-shadow var(--transition);
}

.guide-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
}

.guide-media {
  height: 160px;
  background-color: var(--color-bg-soft);
  background-size: cover;
  background-position: center;
}

.guide-card-body {
  padding: 20px;
}

.guide-card-body h3 {
  font-size: 17px;
  margin-bottom: 8px;
}

.guide-card-body h3 a {
  color: var(--color-text);
}

.guide-card-body h3 a:hover {
  color: var(--color-accent);
}

.guide-card-body p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  margin-bottom: 0;
}

.guide-detail {
  padding-top: 40px;
  border-top: 1px solid var(--color-border);
}

.guide-article {
  margin-bottom: 40px;
  max-width: 720px;
}

.guide-article h3 {
  font-size: 20px;
  margin-bottom: 12px;
}

.guide-article p {
  font-size: 15px;
  line-height: 1.8;
  color: var(--color-muted);
  margin-bottom: 16px;
}

/* ---------- 深度解读页 ---------- */

.insight-section {
  margin-bottom: 48px;
}

.insight-section h2 {
  font-size: 22px;
  margin-bottom: 12px;
}

.insight-section > p {
  font-size: 15px;
  color: var(--color-muted);
  margin-bottom: 24px;
  max-width: 720px;
}

.insight-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.insight-item {
  padding: 20px 24px;
  background-color: var(--color-bg-soft);
  border-radius: var(--radius);
  transition: background-color var(--transition);
}

.insight-item:hover {
  background-color: #e9ebf0;
}

.item-text h3 {
  font-size: 17px;
  margin-bottom: 8px;
}

.item-text h3 a {
  color: var(--color-text);
}

.item-text h3 a:hover {
  color: var(--color-accent);
}

.item-text p {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.6;
  margin-bottom: 8px;
}

.insight-item > a {
  font-size: 14px;
  font-weight: 600;
}

.item-date {
  display: block;
  font-size: 13px;
  color: var(--color-muted);
  margin-top: 8px;
}

/* ---------- 404 页 ---------- */

.error-main {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 80px var(--container-padding);
  flex: 1;
}

.error-content {
  text-align: center;
  max-width: 560px;
}

.error-content h1 {
  font-size: 48px;
  color: var(--color-accent);
  margin-bottom: 16px;
}

.error-lead {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 12px;
}

.error-text {
  font-size: 15px;
  color: var(--color-muted);
  margin-bottom: 32px;
}

.error-action {
  display: inline-block;
  padding: 12px 32px;
  background-color: var(--color-accent);
  color: var(--color-white);
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  transition: background-color var(--transition);
}

.error-action:hover {
  background-color: var(--color-accent-light);
  color: var(--color-white);
}

/* ==========================================================================
   responsive — 移动端适配
   ========================================================================== */

@media (max-width: 1024px) {
  .page-layout {
    grid-template-columns: 1fr 280px;
    gap: 24px;
  }

  .sidebar-left .page-layout {
    grid-template-columns: 280px 1fr;
  }

  .hero-section {
    gap: 32px;
  }

  .channel-item {
    grid-template-columns: 1fr 200px;
  }
}

@media (max-width: 900px) {
  .page-layout {
    grid-template-columns: 1fr;
  }

  .sidebar-left .page-layout {
    grid-template-columns: 1fr;
  }

  .channel-sidebar {
    position: static;
    order: -1;
  }

  .sidebar {
    order: -1;
  }

  .intro-layout {
    grid-template-columns: 1fr;
  }

  /* 移动端导航 */
  .nav-toggle {
    display: flex;
    margin-left: auto;
  }

  .site-nav {
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-border);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.08);
    margin-left: 0;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 0;
  }

  .nav-list.is-open {
    display: flex;
  }

  .nav-list li a {
    padding: 14px 24px;
    border-radius: 0;
    border-bottom: 1px solid var(--color-border);
  }

  .nav-list li:last-child a {
    border-bottom: none;
  }

  .footer-links {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
  }
}

@media (max-width: 768px) {
  :root {
    --container-padding: 16px;
  }

  .header-inner {
    height: 64px;
  }

  .brand-tagline {
    display: none;
  }

  .hero-section {
    grid-template-columns: 1fr;
    padding: 40px 0;
    gap: 24px;
  }

  .hero-media {
    order: -1;
  }

  .hero-media img {
    height: 220px;
  }

  .hero-title {
    font-size: 26px;
  }

  .hero-lead {
    font-size: 16px;
  }

  .topic-cards,
  .topic-grid .topic-cards {
    grid-template-columns: 1fr;
  }

  .channel-item {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .channel-figure img {
    height: 180px;
  }

  .guide-list {
    grid-template-columns: 1fr;
  }

  .latest-item {
    flex-direction: column;
    gap: 8px;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .page-title {
    font-size: 26px;
  }

  .section-title {
    font-size: 20px;
  }
}

@media (max-width: 480px) {
  .hero-cta {
    flex-direction: column;
    align-items: stretch;
  }

  .btn-primary,
  .btn-secondary {
    text-align: center;
  }

  .footer-links {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .editor-pick-item {
    padding: 16px;
  }

  .channel-tags {
    gap: 8px;
  }

  .channel-tag {
    padding: 8px 16px;
    font-size: 13px;
  }

  .error-content h1 {
    font-size: 36px;
  }
}