/* ==========================================================================
   51吃瓜今日 - 全站样式表
   视觉方向：售后支持风（深蓝+浅灰，高可读，清晰信任）
   分组：base / layout / components / pages / responsive
   ========================================================================== */

/* ==========================================================================
   Base - 基础重置与全局变量
   ========================================================================== */

:root {
  --color-primary: #1a3a5c;
  --color-primary-dark: #142e4a;
  --color-bg: #f5f7fa;
  --color-surface: #ffffff;
  --color-text: #333333;
  --color-text-light: #5a6b7b;
  --color-accent: #d9a441;
  --color-border: #e3e8ee;
  --color-focus: #d9a441;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --container-width: 1200px;
  --header-height: 64px;
  --header-height-scrolled: 48px;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

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

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

ul,
ol {
  list-style: none;
}

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

h1 {
  font-size: 28px;
}

h2 {
  font-size: 22px;
}

h3 {
  font-size: 18px;
}

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

/* ==========================================================================
   Layout - 全局布局骨架
   ========================================================================== */

.site-body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-height);
  transition: height var(--transition-base), box-shadow var(--transition-base);
}

.site-header.is-scrolled {
  height: var(--header-height-scrolled);
  box-shadow: 0 2px 8px rgba(26, 58, 92, 0.08);
}

.header-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  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: 22px;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 0.02em;
}

.brand-slogan {
  font-size: 12px;
  color: var(--color-text-light);
}

.site-nav {
  display: flex;
  align-items: center;
}

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

.nav-list li a {
  display: block;
  padding: 8px 14px;
  font-size: 15px;
  font-weight: 500;
  color: var(--color-text);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-list li a:hover {
  color: var(--color-primary);
  background-color: rgba(26, 58, 92, 0.06);
}

.nav-list li a.is-current {
  color: var(--color-primary);
  background-color: rgba(26, 58, 92, 0.1);
  font-weight: 600;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 8px;
  gap: 5px;
  border-radius: var(--radius-sm);
}

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

.site-main {
  flex: 1 0 auto;
}

.site-footer {
  background-color: var(--color-primary);
  color: rgba(255, 255, 255, 0.85);
  margin-top: auto;
}

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

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

.footer-name {
  font-size: 20px;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 6px;
}

.footer-desc {
  font-size: 14px;
  line-height: 1.6;
  max-width: 420px;
  color: rgba(255, 255, 255, 0.75);
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  padding: 32px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.footer-col h3 {
  font-size: 15px;
  font-weight: 600;
  color: #ffffff;
  margin-bottom: 14px;
}

.footer-col ul li {
  margin-bottom: 8px;
}

.footer-col ul li a {
  font-size: 14px;
  color: rgba(255, 255, 255, 0.75);
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  padding-top: 24px;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.55);
}

/* ==========================================================================
   Components - 通用组件
   ========================================================================== */

/* 面包屑 */
.breadcrumb {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 16px 24px 0;
  font-size: 14px;
  color: var(--color-text-light);
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

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

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

.breadcrumb-sep {
  color: #b0b8c0;
}

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

/* 页面标题区 */
.page-header {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 32px 24px 24px;
}

.page-title {
  font-size: 28px;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 8px;
}

.page-description {
  font-size: 16px;
  color: var(--color-text-light);
  max-width: 720px;
  line-height: 1.6;
}

/* 区块标题 */
.section-title {
  font-size: 22px;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 20px;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 22px;
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}

/* ==========================================================================
   Pages - 首页
   ========================================================================== */

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

/* 首屏焦点报道 */
.hero-section {
  padding: 32px 0 16px;
}

.hero-card {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 0;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: 0 4px 16px rgba(26, 58, 92, 0.08);
}

.hero-media {
  position: relative;
  min-height: 300px;
}

.hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  position: absolute;
  inset: 0;
}

.hero-content {
  padding: 36px 32px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.hero-tag {
  display: inline-block;
  background-color: rgba(217, 164, 65, 0.15);
  color: var(--color-accent);
  font-size: 13px;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 999px;
  margin-bottom: 14px;
  align-self: flex-start;
}

.hero-content h1 {
  font-size: 26px;
  line-height: 1.3;
  margin-bottom: 12px;
}

.hero-summary {
  font-size: 15px;
  color: var(--color-text-light);
  line-height: 1.7;
  margin-bottom: 20px;
}

.hero-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-weight: 600;
  color: var(--color-primary);
}

.hero-link::after {
  content: "→";
  transition: transform var(--transition-fast);
}

.hero-link:hover::after {
  transform: translateX(4px);
}

/* 频道分类导航条 */
.channel-strip {
  padding: 32px 0;
}

.channel-strip h2 {
  font-size: 22px;
  margin-bottom: 6px;
}

.section-desc {
  color: var(--color-text-light);
  font-size: 14px;
  margin-bottom: 20px;
  max-width: 640px;
}

.channel-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.channel-tag {
  display: inline-flex;
  align-items: center;
  padding: 8px 18px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text);
  transition: border-color var(--transition-fast), color var(--transition-fast),
    background-color var(--transition-fast);
}

.channel-tag:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background-color: rgba(26, 58, 92, 0.04);
}

/* 最新动态 */
.latest-section {
  padding: 16px 0 32px;
}

.section-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

.section-head h2 {
  font-size: 22px;
}

.section-more {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-primary);
}

.latest-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.latest-item {
  padding: 18px 0;
  border-bottom: 1px solid var(--color-border);
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
  align-items: baseline;
}

.latest-item:first-child {
  padding-top: 0;
}

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

.latest-item h3 {
  font-size: 17px;
  font-weight: 600;
}

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

.latest-item h3 a:hover {
  color: var(--color-primary);
}

.item-summary {
  font-size: 14px;
  color: var(--color-text-light);
  grid-column: 1 / -1;
  margin-top: -6px;
  max-width: 860px;
}

.latest-item time {
  font-size: 13px;
  white-space: nowrap;
}

/* 专题推荐 */
.topic-section {
  padding: 32px 0;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

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

.topic-card:hover {
  box-shadow: 0 6px 20px rgba(26, 58, 92, 0.1);
  transform: translateY(-2px);
}

.topic-card img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.topic-card h3 {
  padding: 16px 16px 4px;
  font-size: 17px;
}

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

.topic-card h3 a:hover {
  color: var(--color-primary);
}

.card-summary {
  padding: 0 16px 16px;
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.6;
}

/* 编辑推荐 */
.picks-section {
  padding: 32px 0;
}

.picks-section h2 {
  font-size: 22px;
  margin-bottom: 20px;
}

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

.pick-item {
  background-color: var(--color-surface);
  border-radius: var(--radius-md);
  padding: 18px 20px;
  border-left: 3px solid var(--color-accent);
}

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

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

.pick-content h3 a:hover {
  color: var(--color-primary);
}

.pick-reason {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.6;
}

/* 来源与反馈 */
.source-section {
  padding: 32px 0;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  margin-top: 16px;
}

.source-section h2 {
  font-size: 20px;
  padding: 0 24px;
  margin-bottom: 12px;
}

.source-content {
  padding: 0 24px;
}

.source-content p {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.7;
  margin-bottom: 10px;
}

.source-content a {
  font-weight: 500;
}

/* ==========================================================================
   Pages - 内页通用
   ========================================================================== */

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

/* 频道分类页 */
.channel-section {
  padding: 8px 0 32px;
}

.channel-section h2 {
  font-size: 22px;
  margin-bottom: 20px;
}

.channel-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.channel-card {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 24px;
  border: 1px solid var(--color-border);
  transition: box-shadow var(--transition-base), transform var(--transition-base);
}

.channel-card:hover {
  box-shadow: 0 6px 20px rgba(26, 58, 92, 0.08);
  transform: translateY(-2px);
}

.channel-card img {
  width: 48px;
  height: 48px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  margin-bottom: 14px;
}

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

.channel-card p {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.6;
  margin-bottom: 12px;
}

.channel-card a {
  font-size: 14px;
  font-weight: 500;
}

.channel-desc-section {
  padding: 24px 0 32px;
}

.channel-desc-section h2 {
  font-size: 22px;
  margin-bottom: 16px;
}

.desc-content {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 24px;
  border: 1px solid var(--color-border);
}

.desc-content p {
  font-size: 15px;
  color: var(--color-text);
  line-height: 1.8;
  margin-bottom: 14px;
}

.desc-content p:last-child {
  margin-bottom: 0;
}

.channel-related {
  padding: 8px 0 24px;
}

.channel-related h3 {
  font-size: 18px;
  margin-bottom: 14px;
}

.channel-related ul {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.channel-related ul li a {
  display: inline-block;
  padding: 6px 14px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: 14px;
  color: var(--color-text);
}

.channel-related ul li a:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* 内容专题页 */
.section-heading {
  margin-bottom: 24px;
}

.section-heading h2 {
  font-size: 22px;
  margin-bottom: 6px;
}

.section-heading p {
  color: var(--color-text-light);
  font-size: 15px;
}

.topic-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.topic-card-link {
  display: block;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--color-border);
  transition: box-shadow var(--transition-base), transform var(--transition-base);
  height: 100%;
}

.topic-card-link:hover {
  box-shadow: 0 6px 20px rgba(26, 58, 92, 0.1);
  transform: translateY(-2px);
}

.topic-figure {
  aspect-ratio: 16 / 9;
  overflow: hidden;
}

.topic-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.topic-body {
  padding: 16px;
}

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

.topic-body p {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.6;
  margin-bottom: 10px;
}

.topic-meta {
  font-size: 13px;
  color: var(--color-accent);
  font-weight: 500;
}

.topic-intro {
  padding: 32px 0;
}

.intro-inner {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 32px;
  align-items: center;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 32px;
  border: 1px solid var(--color-border);
}

.intro-text h2 {
  font-size: 22px;
  margin-bottom: 14px;
}

.intro-text p {
  font-size: 15px;
  color: var(--color-text);
  line-height: 1.8;
  margin-bottom: 12px;
}

.intro-text p:last-child {
  margin-bottom: 0;
}

.intro-figure {
  border-radius: var(--radius-md);
  overflow: hidden;
}

.intro-figure img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

/* 实用指南页 */
.page-layout {
  display: grid;
  gap: 32px;
}

.sidebar-left {
  grid-template-columns: 260px 1fr;
}

.sidebar-left .guide-toc {
  grid-column: 1;
}

.sidebar-left .guide-content {
  grid-column: 2;
}

.guide-toc {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 20px;
  border: 1px solid var(--color-border);
  align-self: start;
  position: sticky;
  top: calc(var(--header-height) + 20px);
}

.guide-toc h2 {
  font-size: 16px;
  margin-bottom: 14px;
}

.guide-toc ul li {
  margin-bottom: 4px;
}

.guide-toc ul li a {
  display: block;
  padding: 8px 12px;
  font-size: 14px;
  color: var(--color-text);
  border-radius: var(--radius-sm);
  border-left: 2px solid transparent;
  transition: color var(--transition-fast), border-color var(--transition-fast),
    background-color var(--transition-fast);
}

.guide-toc ul li a:hover {
  color: var(--color-primary);
  border-left-color: var(--color-accent);
  background-color: rgba(26, 58, 92, 0.04);
}

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

.guide-list {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 24px;
  border: 1px solid var(--color-border);
  margin-bottom: 24px;
}

.guide-list h2 {
  font-size: 20px;
  margin-bottom: 10px;
}

.guide-list p {
  font-size: 15px;
  color: var(--color-text);
  line-height: 1.7;
  margin-bottom: 16px;
}

.guide-media {
  border-radius: var(--radius-md);
  overflow: hidden;
}

.guide-media img {
  width: 100%;
  aspect-ratio: 21 / 9;
  object-fit: cover;
}

.guide-media figcaption {
  padding: 10px 12px;
  font-size: 13px;
  color: var(--color-text-light);
  background-color: var(--color-bg);
}

.guide-steps {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.step-block {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 24px;
  border: 1px solid var(--color-border);
  scroll-margin-top: calc(var(--header-height) + 20px);
}

.step-block h3 {
  font-size: 18px;
  margin-bottom: 10px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--color-border);
}

.step-block > p {
  font-size: 15px;
  color: var(--color-text);
  line-height: 1.7;
  margin-bottom: 16px;
}

.step-list {
  counter-reset: step;
}

.step-list li {
  counter-increment: step;
  position: relative;
  padding-left: 40px;
  margin-bottom: 12px;
  font-size: 15px;
  line-height: 1.7;
}

.step-list li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 2px;
  width: 26px;
  height: 26px;
  background-color: var(--color-primary);
  color: #ffffff;
  font-size: 13px;
  font-weight: 600;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step-block > p:last-child {
  margin-bottom: 0;
}

.step-block > p a {
  font-weight: 500;
}

/* 深度解读页 */
.article-list {
  padding: 8px 0 32px;
}

.article-items {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.article-row {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 20px;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--color-border);
  transition: box-shadow var(--transition-base);
}

.article-row:hover {
  box-shadow: 0 6px 20px rgba(26, 58, 92, 0.08);
}

.article-media {
  min-height: 140px;
}

.article-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.article-content {
  padding: 20px 20px 20px 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-width: 0;
}

.article-title {
  font-size: 18px;
  margin-bottom: 8px;
}

.article-title a {
  color: var(--color-text);
}

.article-title a:hover {
  color: var(--color-primary);
}

.article-meta {
  font-size: 13px;
  color: var(--color-text-light);
  margin-bottom: 8px;
}

.article-summary {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.6;
  margin-bottom: 12px;
}

.article-link {
  font-size: 14px;
  font-weight: 500;
  align-self: flex-start;
}

.analysis-framework {
  padding: 32px 0;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 32px;
  border: 1px solid var(--color-border);
}

.framework-intro {
  margin-bottom: 24px;
}

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

.framework-steps {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-bottom: 24px;
}

.framework-step {
  background-color: var(--color-bg);
  border-radius: var(--radius-md);
  padding: 20px;
}

.framework-step-title {
  font-size: 16px;
  margin-bottom: 8px;
  color: var(--color-primary);
}

.framework-step p {
  font-size: 14px;
  color: var(--color-text-light);
  line-height: 1.6;
}

.framework-note {
  font-size: 14px;
  color: var(--color-text-light);
  border-top: 1px solid var(--color-border);
  padding-top: 16px;
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.framework-note a {
  font-weight: 500;
}

.related-links {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  padding: 24px 0;
}

.related-links-label {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-primary);
  margin-right: 4px;
}

.related-links-item {
  display: inline-block;
  padding: 6px 14px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: 14px;
  color: var(--color-text);
}

.related-links-item:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* 常见问题页 */
.faq-section {
  padding: 8px 0 32px;
}

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

.faq-item {
  background-color: var(--color-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  overflow: hidden;
}

.faq-item summary {
  padding: 18px 20px;
  font-size: 16px;
  font-weight: 600;
  color: var(--color-text);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  transition: color var(--transition-fast);
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  font-size: 22px;
  font-weight: 400;
  color: var(--color-primary);
  transition: transform var(--transition-fast);
  flex-shrink: 0;
}

.faq-item[open] summary::after {
  content: "−";
}

.faq-item summary:hover {
  color: var(--color-primary);
}

.faq-item p {
  padding: 0 20px 18px;
  font-size: 15px;
  color: var(--color-text-light);
  line-height: 1.7;
}

.feedback-section {
  padding: 24px 0 32px;
}

.feedback-content {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 24px;
  border: 1px solid var(--color-border);
}

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

.feedback-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 16px;
}

.feedback-list li {
  font-size: 15px;
  line-height: 1.7;
}

.feedback-list strong {
  color: var(--color-primary);
  margin-right: 6px;
}

.feedback-list a {
  font-weight: 500;
}

.feedback-content > p:last-child {
  margin-bottom: 0;
}

.faq-figure {
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-top: 20px;
}

.faq-figure img {
  width: 100%;
  aspect-ratio: 21 / 6;
  object-fit: cover;
}

.faq-figure figcaption {
  padding: 10px 12px;
  font-size: 13px;
  color: var(--color-text-light);
  background-color: var(--color-bg);
}

/* 404 页 */
.error-main {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 80px 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
}

.error-panel {
  text-align: center;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 48px 40px;
  border: 1px solid var(--color-border);
  max-width: 560px;
  width: 100%;
}

.error-code {
  font-size: 72px;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: 16px;
}

.error-panel h1 {
  font-size: 24px;
  margin-bottom: 12px;
}

.error-desc {
  font-size: 15px;
  color: var(--color-text-light);
  margin-bottom: 24px;
}

.error-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  background-color: var(--color-primary);
  color: #ffffff;
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 24px;
  transition: background-color var(--transition-fast);
}

.error-btn:hover {
  background-color: var(--color-primary-dark);
  color: #ffffff;
}

.error-links {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.error-links a {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-primary);
  padding: 6px 12px;
}

/* ==========================================================================
   Responsive - 响应式
   ========================================================================== */

@media (max-width: 1024px) {
  .channel-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

@media (max-width: 768px) {
  :root {
    --header-height: 56px;
  }

  .header-inner {
    padding: 0 16px;
    gap: 16px;
  }

  .brand-name {
    font-size: 19px;
  }

  .brand-slogan {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    box-shadow: 0 4px 12px rgba(26, 58, 92, 0.08);
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-base);
  }

  .site-nav.is-open {
    max-height: 360px;
    overflow-y: auto;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    padding: 8px 16px 16px;
    gap: 0;
  }

  .nav-list li a {
    padding: 12px 8px;
    border-radius: var(--radius-sm);
    font-size: 15px;
  }

  .home-main,
  .inner-main {
    padding: 0 16px 32px;
  }

  .breadcrumb {
    padding: 12px 16px 0;
  }

  .page-header {
    padding: 24px 16px 20px;
  }

  .page-title {
    font-size: 24px;
  }

  .hero-card {
    grid-template-columns: 1fr;
  }

  .hero-media {
    min-height: 200px;
  }

  .hero-media img {
    position: relative;
    aspect-ratio: 16 / 9;
  }

  .hero-content {
    padding: 24px 20px;
  }

  .hero-content h1 {
    font-size: 22px;
  }

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

  .latest-item {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .latest-item time {
    grid-row: auto;
  }

  .item-summary {
    grid-column: 1;
  }

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

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

  .intro-inner {
    grid-template-columns: 1fr;
    padding: 24px 20px;
    gap: 20px;
  }

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

  .sidebar-left .guide-toc {
    grid-column: 1;
  }

  .sidebar-left .guide-content {
    grid-column: 1;
  }

  .guide-toc {
    position: static;
  }

  .guide-toc ul {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
  }

  .guide-toc ul li {
    margin-bottom: 0;
  }

  .guide-toc ul li a {
    border-left: none;
    border: 1px solid var(--color-border);
    padding: 6px 12px;
    font-size: 13px;
  }

  .guide-toc ul li a:hover {
    border-left-color: var(--color-border);
  }

  .article-row {
    grid-template-columns: 1fr;
  }

  .article-content {
    padding: 0 20px 20px;
  }

  .article-media {
    aspect-ratio: 16 / 9;
  }

  .article-media img {
    position: relative;
  }

  .framework-steps {
    grid-template-columns: 1fr;
  }

  .analysis-framework {
    padding: 24px 20px;
  }

  .footer-inner {
    padding: 32px 16px 20px;
  }

  .footer-links {
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    padding: 24px 0;
  }

  .footer-brand {
    margin-bottom: 24px;
  }

  .error-main {
    padding: 48px 16px;
  }

  .error-panel {
    padding: 32px 20px;
  }

  .error-code {
    font-size: 56px;
  }
}

@media (max-width: 480px) {
  .footer-links {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .channel-tags {
    gap: 8px;
  }

  .channel-tag {
    padding: 6px 14px;
    font-size: 13px;
  }

  .topic-card h3 {
    font-size: 16px;
  }

  .step-block {
    padding: 20px 16px;
  }

  .faq-item summary {
    padding: 16px 16px;
    font-size: 15px;
  }

  .faq-item p {
    padding: 0 16px 16px;
  }
}