/* ============================================================
   base — 全站基础变量、重置与字体
   ============================================================ */
:root {
  --color-primary: #0b3d5c;
  --color-primary-light: #155a7a;
  --color-secondary: #5c9bb0;
  --color-secondary-light: #e8f1f4;
  --color-paper: #f4e9d8;
  --color-paper-light: #faf5ec;
  --color-ink: #222222;
  --color-ink-light: #555555;
  --color-white: #ffffff;
  --color-border: #d9d0c0;
  --color-footer-bg: #eef4f6;
  --color-footer-text: #44555e;
  --font-heading: "Songti SC", "SimSun", "STSong", serif;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --container-width: 1200px;
  --radius: 8px;
  --shadow: 0 2px 8px rgba(11, 61, 92, 0.08);
  --space-section: 48px;
  --header-height: 64px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-ink);
  background-color: var(--color-white);
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

ul,
ol {
  list-style: none;
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-heading);
  line-height: 1.4;
  color: var(--color-primary);
}

h1 {
  font-size: 28px;
  font-weight: 700;
}

h2 {
  font-size: 20px;
  font-weight: 700;
}

h3 {
  font-size: 16px;
  font-weight: 600;
}

p {
  font-size: 14px;
  line-height: 1.8;
  color: var(--color-ink-light);
}

time {
  font-size: 12px;
  color: #888;
}

/* ============================================================
   layout — 全站统一布局骨架
   ============================================================ */
.site-body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.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 20px;
  height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.site-brand {
  font-family: var(--font-heading);
  font-size: 22px;
  font-weight: 700;
  white-space: nowrap;
}

.site-brand a {
  color: var(--color-primary);
}

.site-brand a:hover {
  color: var(--color-primary-light);
}

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

.nav-list {
  display: flex;
  gap: 8px;
}

.nav-list a {
  display: block;
  padding: 8px 16px;
  border-radius: 4px;
  font-size: 15px;
  color: var(--color-ink);
  line-height: 1.5;
}

.nav-list a:hover {
  color: var(--color-primary);
  background-color: var(--color-secondary-light);
}

.nav-list a.is-current {
  color: var(--color-white);
  background-color: var(--color-primary);
}

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

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-primary);
  border-radius: 2px;
  transition: background-color 0.2s ease;
}

.site-main {
  flex: 1;
}

.site-main.inner-main {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 32px 20px 56px;
  width: 100%;
}

.site-footer {
  background-color: var(--color-footer-bg);
  border-top: 1px solid var(--color-border);
  padding: 40px 0 0;
  margin-top: auto;
}

.footer-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 20px;
}

.footer-brand {
  padding-bottom: 24px;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 24px;
}

.footer-slogan {
  font-family: var(--font-heading);
  font-size: 18px;
  color: var(--color-primary);
  margin-bottom: 8px;
}

.footer-desc {
  font-size: 13px;
  color: var(--color-footer-text);
  max-width: 560px;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
  padding-bottom: 32px;
}

.footer-col h3 {
  font-size: 15px;
  margin-bottom: 12px;
  color: var(--color-primary);
}

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

.footer-col a {
  font-size: 13px;
  color: var(--color-footer-text);
}

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

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding: 16px 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.footer-bottom p {
  font-size: 12px;
  color: #77888f;
}

.back-to-top {
  font-size: 13px;
  color: var(--color-primary);
  white-space: nowrap;
}

.back-to-top:hover {
  color: var(--color-secondary);
}

/* 内页面包屑 */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  margin-bottom: 16px;
  color: #888;
}

.breadcrumb-sep {
  color: #bbb;
}

.breadcrumb-current {
  color: var(--color-ink-light);
}

.page-header {
  margin-bottom: 32px;
}

.page-title {
  font-size: 28px;
  margin-bottom: 8px;
}

.page-description {
  font-size: 14px;
  max-width: 720px;
}

/* ============================================================
   components — 全站通用组件
   ============================================================ */
/* 按钮 */
.btn-primary,
.btn-secondary {
  display: inline-block;
  padding: 10px 24px;
  border-radius: var(--radius);
  font-size: 15px;
  line-height: 1.6;
  text-align: center;
  transition: background-color 0.2s ease, color 0.2s ease;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

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

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

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

.btn-secondary:hover {
  background-color: var(--color-secondary);
  color: var(--color-white);
}

.btn-text {
  display: inline-block;
  padding: 8px 0;
  color: var(--color-primary);
  font-size: 14px;
}

.btn-text:hover {
  color: var(--color-secondary);
}

/* 列表通用 */
.more-link {
  display: inline-block;
  margin-top: 16px;
  font-size: 14px;
  color: var(--color-primary);
}

.more-link:hover {
  color: var(--color-secondary);
}

.text-link {
  display: inline-block;
  font-size: 14px;
  color: var(--color-primary);
}

.text-link:hover {
  color: var(--color-secondary);
}

/* 侧栏 */
.sidebar {
  width: 280px;
  flex-shrink: 0;
}

.sidebar-block {
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 24px;
}

.sidebar-block h2 {
  font-size: 16px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.sidebar-links li {
  margin-bottom: 10px;
}

.sidebar-links a {
  font-size: 14px;
  color: var(--color-ink-light);
  display: inline-block;
  padding: 4px 0;
}

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

/* 相关链接 */
.related-links {
  margin-top: 32px;
  padding-top: 16px;
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  align-items: center;
}

.related-links p {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.related-links-label {
  font-size: 13px;
  color: #888;
}

.related-links-item {
  font-size: 13px;
  color: var(--color-primary);
}

/* ============================================================
   pages — 首页
   ============================================================ */
.home-main {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 20px 56px;
  width: 100%;
}

/* 首屏固定高度区 */
.hero-fixed {
  padding: 32px 0 40px;
}

.hero-visual {
  margin-bottom: 24px;
}

.hero-figure {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  width: 100%;
  height: 260px;
}

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

.hero-content {
  max-width: 720px;
  margin-bottom: 32px;
}

.hero-content h1 {
  font-size: 28px;
  margin-bottom: 12px;
}

.hero-lead {
  font-size: 16px;
  margin-bottom: 20px;
}

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

/* 首屏三列 */
.home-columns {
  display: grid;
  grid-template-columns: 1fr 1.2fr 0.9fr;
  gap: 24px;
  align-items: start;
}

.board-cards,
.hot-threads,
.notice-sidebar {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
}

.board-cards h2,
.hot-threads h2,
.notice-sidebar h2 {
  font-size: 17px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.board-card-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.board-card {
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 14px;
  transition: box-shadow 0.2s ease;
}

.board-card:hover {
  box-shadow: var(--shadow);
}

.board-card h3 {
  font-size: 15px;
  margin-bottom: 6px;
}

.board-card p {
  font-size: 13px;
  margin-bottom: 8px;
}

.meta-info {
  font-size: 12px;
  color: #888;
}

/* 热帖列表 */
.hot-list {
  display: flex;
  flex-direction: column;
}

.hot-item {
  padding: 10px 0;
  border-bottom: 1px dashed var(--color-border);
  display: flex;
  align-items: baseline;
  gap: 8px;
  flex-wrap: wrap;
}

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

.hot-item a {
  font-size: 14px;
  color: var(--color-ink);
  flex: 1;
  min-width: 160px;
}

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

.tag {
  font-size: 12px;
  background-color: var(--color-secondary-light);
  color: var(--color-primary);
  padding: 2px 8px;
  border-radius: 3px;
  white-space: nowrap;
}

.replies {
  font-size: 12px;
  color: #888;
  white-space: nowrap;
}

/* 公告侧栏 */
.notice-item {
  padding: 10px 0;
  border-bottom: 1px dashed var(--color-border);
}

.notice-item:last-of-type {
  border-bottom: none;
}

.notice-item h3 {
  font-size: 14px;
  margin-bottom: 4px;
}

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

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

.notice-item p {
  font-size: 13px;
}

.rules-digest {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.rules-digest p {
  font-size: 13px;
}

.rules-digest a {
  font-size: 13px;
}

/* 时间轴 */
.timeline-section {
  margin-top: 48px;
}

.timeline-section > h2 {
  font-size: 20px;
  margin-bottom: 24px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.timeline {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  position: relative;
}

.timeline-node {
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  position: relative;
}

.timeline-node::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background-color: var(--color-secondary);
  border-radius: var(--radius) var(--radius) 0 0;
}

.timeline-node h3 {
  font-size: 15px;
  margin-bottom: 8px;
}

.timeline-node h3 a {
  color: var(--color-primary);
}

.timeline-node p {
  font-size: 13px;
  margin-bottom: 8px;
}

/* 专题封面入口 */
.featured-topic {
  margin-top: 48px;
}

.featured-topic > h2 {
  font-size: 20px;
  margin-bottom: 24px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.featured-topic .topic-entry {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-bottom: 24px;
}

.topic-cover {
  overflow: hidden;
  border-radius: var(--radius);
  height: 200px;
  background-color: var(--color-secondary-light);
}

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

.topic-summary {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.topic-code {
  font-size: 12px;
  color: var(--color-secondary);
  margin-bottom: 4px;
  letter-spacing: 0.5px;
}

.topic-summary h3 {
  font-size: 18px;
  margin-bottom: 8px;
}

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

.topic-summary p {
  font-size: 14px;
  margin-bottom: 12px;
}

/* ============================================================
   pages — 版块列表页 boards
   ============================================================ */
.category-nav {
  margin-bottom: 40px;
}

.section-title {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.category-group {
  margin-bottom: 20px;
}

.category-name {
  font-size: 15px;
  margin-bottom: 8px;
  color: var(--color-primary);
}

.category-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
}

.category-links a {
  font-size: 14px;
  color: var(--color-ink-light);
  display: inline-block;
  padding: 4px 0;
}

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

.board-list {
  margin-bottom: 40px;
}

.board-list .board-card {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 20px;
  padding: 16px;
  margin-bottom: 16px;
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: box-shadow 0.2s ease;
}

.board-list .board-card:hover {
  box-shadow: var(--shadow);
}

.board-media {
  overflow: hidden;
  border-radius: var(--radius);
  height: 120px;
  background-color: var(--color-secondary-light);
}

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

.board-info {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.board-name {
  font-size: 17px;
  margin-bottom: 6px;
}

.board-desc {
  font-size: 14px;
  margin-bottom: 8px;
}

.board-meta {
  font-size: 12px;
  color: #888;
}

.board-related {
  margin-top: 8px;
}

.board-related a {
  font-size: 13px;
}

.board-note {
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
}

.board-note p {
  font-size: 14px;
  margin-bottom: 8px;
}

/* ============================================================
   pages — 热帖页 hot
   ============================================================ */
.page-layout {
  display: flex;
  gap: 32px;
  align-items: flex-start;
}

.content-area {
  flex: 1;
  min-width: 0;
}

.hot-section {
  margin-bottom: 40px;
}

.hot-section h2 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.hot-entry {
  display: flex;
  align-items: baseline;
  gap: 8px;
  flex-wrap: wrap;
  flex: 1;
}

.hot-entry a {
  font-size: 14px;
  color: var(--color-ink);
  flex: 1;
  min-width: 160px;
}

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

.hot-meta {
  font-size: 12px;
  color: #888;
  white-space: nowrap;
}

.reply-count {
  font-size: 12px;
  color: var(--color-secondary);
  white-space: nowrap;
}

.last-time {
  font-size: 12px;
  color: #aaa;
  white-space: nowrap;
}

.trend {
  font-size: 12px;
  white-space: nowrap;
}

.trend.up {
  color: #c0392b;
}

.trend.down {
  color: #27ae60;
}

.trend.steady {
  color: #888;
}

.board-tag {
  font-size: 12px;
  background-color: var(--color-paper);
  color: var(--color-primary);
  padding: 2px 8px;
  border-radius: 3px;
  white-space: nowrap;
}

.reply-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 16px;
}

.reply-card {
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 16px;
}

.reply-card blockquote {
  font-size: 14px;
  color: var(--color-ink-light);
  margin-bottom: 8px;
  border-left: 3px solid var(--color-secondary);
  padding-left: 12px;
}

.reply-meta {
  font-size: 12px;
  color: #888;
}

.reply-figure {
  margin-top: 8px;
  overflow: hidden;
  border-radius: var(--radius);
  height: 80px;
}

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

.side-block {
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 24px;
}

.side-block h2 {
  font-size: 16px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag-list a {
  font-size: 13px;
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 4px 12px;
  color: var(--color-ink-light);
}

.tag-list a:hover {
  background-color: var(--color-secondary-light);
  color: var(--color-primary);
  border-color: var(--color-secondary);
}

.category-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.category-list a {
  font-size: 14px;
  color: var(--color-ink-light);
  padding: 4px 0;
}

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

/* ============================================================
   pages — 专题页 topic
   ============================================================ */
.layout-shell {
  display: flex;
  gap: 32px;
  align-items: flex-start;
}

.main-content {
  flex: 1;
  min-width: 0;
}

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

.current-topic h2 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.topic-feature {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
}

.topic-feature .topic-cover {
  width: 100%;
  height: 280px;
  border-radius: 0;
}

.topic-info {
  padding: 24px;
}

.topic-number {
  font-size: 13px;
  color: var(--color-secondary);
  margin-bottom: 8px;
  letter-spacing: 0.5px;
}

.topic-info h2 {
  font-size: 20px;
  margin-bottom: 12px;
  border-bottom: none;
  padding-bottom: 0;
}

.topic-desc {
  font-size: 14px;
  margin-bottom: 16px;
}

.topic-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

.topic-tags li {
  font-size: 12px;
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 2px 10px;
  color: var(--color-ink-light);
}

.topic-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.past-topics {
  margin-bottom: 48px;
}

.past-topics h2 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

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

.past-topic-item {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 16px;
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 12px;
  transition: box-shadow 0.2s ease;
}

.past-topic-item:hover {
  box-shadow: var(--shadow);
}

.topic-thumb {
  overflow: hidden;
  border-radius: var(--radius);
  height: 80px;
  background-color: var(--color-secondary-light);
}

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

.past-topic-info {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.past-topic-info h3 {
  font-size: 15px;
  margin-bottom: 4px;
}

.past-topic-info h3 a {
  color: var(--color-ink);
}

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

.topic-date {
  font-size: 12px;
  color: #888;
}

/* ============================================================
   pages — 归档页 archive
   ============================================================ */
.year-index {
  margin-bottom: 40px;
}

.year-index h2 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.year-links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.year-link {
  display: inline-block;
  padding: 8px 20px;
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 16px;
  color: var(--color-primary);
  font-family: var(--font-heading);
}

.year-link:hover {
  background-color: var(--color-secondary-light);
  border-color: var(--color-secondary);
}

.monthly-list {
  margin-bottom: 48px;
}

.monthly-list h2 {
  font-size: 18px;
  margin-bottom: 24px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.archive-group {
  margin-bottom: 32px;
}

.archive-group h3 {
  font-size: 16px;
  margin-bottom: 12px;
  padding-left: 12px;
  border-left: 3px solid var(--color-secondary);
}

.archive-items {
  display: flex;
  flex-direction: column;
}

.archive-item {
  padding: 8px 0;
  border-bottom: 1px dashed var(--color-border);
  display: flex;
  align-items: baseline;
  gap: 8px;
  flex-wrap: wrap;
}

.archive-link {
  font-size: 14px;
  color: var(--color-ink);
  flex: 1;
  min-width: 160px;
}

.archive-link:hover {
  color: var(--color-primary);
}

.archive-meta {
  font-size: 12px;
  color: #888;
  white-space: nowrap;
}

.archive-replies {
  font-size: 12px;
  color: var(--color-secondary);
  white-space: nowrap;
}

.archive-board {
  font-size: 12px;
  background-color: var(--color-secondary-light);
  color: var(--color-primary);
  padding: 2px 8px;
  border-radius: 3px;
  white-space: nowrap;
}

.archive-date {
  font-size: 12px;
  color: #aaa;
  white-space: nowrap;
}

.topic-archive {
  margin-bottom: 40px;
}

.topic-archive h2 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.topic-archive-list {
  display: flex;
  flex-direction: column;
}

.topic-archive-item {
  padding: 8px 0;
  border-bottom: 1px dashed var(--color-border);
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.topic-number {
  font-size: 12px;
  color: var(--color-secondary);
  white-space: nowrap;
}

.topic-archive-item a {
  font-size: 14px;
  color: var(--color-ink);
}

.topic-archive-item a:hover {
  color: var(--color-primary);
}

.archive-sidebar {
  width: 280px;
  flex-shrink: 0;
}

/* ============================================================
   pages — 新手指南页 guide
   ============================================================ */
.sidebar-left {
  display: flex;
  gap: 32px;
  align-items: flex-start;
}

.guide-index {
  width: 280px;
  flex-shrink: 0;
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  position: sticky;
  top: calc(var(--header-height) + 20px);
}

.guide-index h2 {
  font-size: 16px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.guide-index ul {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.guide-index a {
  display: block;
  padding: 8px 12px;
  font-size: 14px;
  color: var(--color-ink-light);
  border-radius: 4px;
  line-height: 1.5;
}

.guide-index a:hover {
  background-color: var(--color-secondary-light);
  color: var(--color-primary);
}

.guide-more {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--color-border);
}

.guide-more a {
  display: inline-block;
  padding: 4px 0;
  font-size: 13px;
  color: var(--color-primary);
}

.guide-content {
  flex: 1;
  min-width: 0;
}

.guide-section {
  margin-bottom: 48px;
  scroll-margin-top: calc(var(--header-height) + 20px);
}

.guide-section h2 {
  font-size: 18px;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.guide-section > p {
  font-size: 14px;
  margin-bottom: 16px;
}

.step-list {
  counter-reset: step;
  margin: 16px 0;
}

.step-list li {
  counter-increment: step;
  position: relative;
  padding: 8px 0 8px 40px;
  font-size: 14px;
  color: var(--color-ink-light);
  line-height: 1.8;
}

.step-list li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 8px;
  width: 28px;
  height: 28px;
  background-color: var(--color-primary);
  color: var(--color-white);
  border-radius: 50%;
  font-size: 13px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-body);
}

.step-list a {
  font-size: 14px;
}

.plain-list {
  margin: 16px 0;
}

.plain-list li {
  padding: 8px 0 8px 20px;
  position: relative;
  font-size: 14px;
  color: var(--color-ink-light);
  line-height: 1.8;
}

.plain-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 16px;
  width: 8px;
  height: 8px;
  background-color: var(--color-secondary);
  border-radius: 50%;
}

.guide-figure {
  margin: 20px 0;
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}

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

.guide-figure figcaption {
  padding: 8px 12px;
  font-size: 12px;
  color: #888;
  background-color: var(--color-paper-light);
}

/* ============================================================
   pages — 规则页 rules
   ============================================================ */
.phase-aside {
  width: 280px;
  flex-shrink: 0;
}

.aside-inner {
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  position: sticky;
  top: calc(var(--header-height) + 20px);
}

.aside-inner h2 {
  font-size: 16px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.phase-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.phase-list a {
  display: block;
  padding: 8px 12px;
  font-size: 14px;
  color: var(--color-ink-light);
  border-radius: 4px;
  line-height: 1.5;
}

.phase-list a:hover {
  background-color: var(--color-secondary-light);
  color: var(--color-primary);
}

.aside-note {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--color-border);
}

.aside-note p {
  font-size: 13px;
  margin-bottom: 8px;
}

.rules-content-wrap {
  flex: 1;
  min-width: 0;
}

.rules-figure {
  margin-bottom: 24px;
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}

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

.rules-figure figcaption {
  padding: 8px 12px;
  font-size: 12px;
  color: #888;
  background-color: var(--color-paper-light);
}

.rule-section {
  margin-bottom: 40px;
  scroll-margin-top: calc(var(--header-height) + 20px);
}

.rule-section h2 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

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

.rule-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 16px;
}

.rule-item h3 {
  font-size: 15px;
  margin-bottom: 6px;
}

.rule-item p {
  font-size: 14px;
}

/* ============================================================
   pages — 计划页 plan
   ============================================================ */
.plan-timeline {
  margin-bottom: 48px;
}

.plan-timeline h2 {
  font-size: 18px;
  margin-bottom: 24px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.plan-stage {
  position: relative;
  padding: 0 0 32px 32px;
  border-left: 2px solid var(--color-secondary);
  margin-left: 8px;
}

.plan-stage:last-child {
  padding-bottom: 0;
}

.stage-marker {
  position: relative;
  margin-bottom: 8px;
}

.stage-marker::before {
  content: "";
  position: absolute;
  left: -37px;
  top: 6px;
  width: 12px;
  height: 12px;
  background-color: var(--color-secondary);
  border-radius: 50%;
  border: 3px solid var(--color-white);
  box-shadow: 0 0 0 2px var(--color-secondary);
}

.stage-badge {
  display: inline-block;
  font-size: 12px;
  background-color: var(--color-secondary-light);
  color: var(--color-primary);
  padding: 2px 10px;
  border-radius: 3px;
  margin-bottom: 8px;
}

.plan-stage h3 {
  font-size: 17px;
  margin-bottom: 8px;
}

.plan-stage > p {
  font-size: 14px;
  margin-bottom: 8px;
}

.stage-status {
  font-size: 13px;
  color: #888;
}

.participate {
  margin-bottom: 48px;
}

.participate h2 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.participate-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  align-items: start;
}

.participate-media figure {
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}

.participate-media img {
  width: 100%;
  height: 220px;
  object-fit: cover;
}

.participate-media figcaption {
  padding: 8px 12px;
  font-size: 12px;
  color: #888;
  background-color: var(--color-paper-light);
}

.participate-text p {
  font-size: 14px;
  margin-bottom: 12px;
}

.participate-links {
  margin: 16px 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.participate-links a {
  font-size: 14px;
}

.plan-sidebar {
  width: 280px;
  flex-shrink: 0;
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
}

.plan-sidebar h2 {
  font-size: 16px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.plan-sidebar ul {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.plan-sidebar a {
  font-size: 14px;
  color: var(--color-ink-light);
}

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

/* ============================================================
   pages — 反馈页 feedback
   ============================================================ */
.feedback-intro {
  margin-bottom: 48px;
}

.feedback-intro h2 {
  font-size: 18px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.content-media {
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  margin-bottom: 16px;
}

.content-media-inline {
  max-width: 640px;
}

.content-media img {
  width: 100%;
  height: 220px;
  object-fit: cover;
}

.content-media figcaption {
  padding: 8px 12px;
  font-size: 12px;
  color: #888;
  background-color: var(--color-paper-light);
}

.feedback-intro > p {
  font-size: 14px;
  margin-bottom: 16px;
}

.channel-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin: 16px 0;
}

.channel-item {
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 16px;
}

.channel-item h3 {
  font-size: 15px;
  margin-bottom: 6px;
}

.channel-item p {
  font-size: 14px;
}

.process-steps {
  margin-bottom: 48px;
  background-color: var(--color-paper-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
}

.process-steps h2 {
  font-size: 18px;
  margin-bottom: 8px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.process-steps > p {
  font-size: 14px;
  margin-bottom: 20px;
}

.process-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  counter-reset: process;
}

.process-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 16px;
  position: relative;
}

.process-num {
  display: inline-block;
  width: 28px;
  height: 28px;
  background-color: var(--color-primary);
  color: var(--color-white);
  border-radius: 50%;
  font-size: 13px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 8px;
  font-family: var(--font-body);
}

.process-item h3 {
  font-size: 15px;
  margin-bottom: 6px;
}

.process-item p {
  font-size: 13px;
}

.public-replies {
  margin-bottom: 48px;
}

.public-replies h2 {
  font-size: 18px;
  margin-bottom: 8px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-secondary);
}

.public-replies > p {
  font-size: 14px;
  margin-bottom: 16px;
}

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

.reply-item {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 16px;
}

.reply-item h3 {
  font-size: 15px;
  margin-bottom: 4px;
}

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

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

.reply-meta {
  font-size: 12px;
  color: #888;
  margin-bottom: 8px;
}

.reply-item > p {
  font-size: 14px;
  margin-bottom: 8px;
}

.reply-item > a {
  font-size: 13px;
}

.feedback-sidebar {
  width: 280px;
  flex-shrink: 0;
}

/* ============================================================
   pages — 404 页
   ============================================================ */
.error-main {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
  padding: 48px 20px;
}

.error-content {
  text-align: center;
  max-width: 480px;
}

.error-code {
  font-family: var(--font-heading);
  font-size: 72px;
  font-weight: 700;
  color: var(--color-secondary);
  line-height: 1.2;
  margin-bottom: 16px;
}

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

.error-desc {
  font-size: 14px;
  margin-bottom: 24px;
}

.error-home {
  display: inline-block;
  padding: 10px 24px;
  background-color: var(--color-primary);
  color: var(--color-white);
  border-radius: var(--radius);
  font-size: 15px;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.error-home:hover {
  background-color: var(--color-primary-light);
  color: var(--color-white);
}

/* ============================================================
   responsive — 响应式
   ============================================================ */
@media (max-width: 1024px) {
  .home-columns {
    grid-template-columns: 1fr 1fr;
  }

  .notice-sidebar {
    grid-column: 1 / -1;
  }

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

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

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

  .participate-content {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .header-inner {
    padding: 0 16px;
  }

  .nav-toggle {
    display: flex;
  }

  .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: var(--shadow);
  }

  .nav-list {
    display: none;
    flex-direction: column;
    padding: 12px 16px;
    gap: 4px;
  }

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

  .nav-list a {
    padding: 12px 16px;
    font-size: 16px;
    border-radius: 4px;
  }

  .site-main.inner-main {
    padding: 24px 16px 40px;
  }

  .home-main {
    padding: 0 16px 40px;
  }

  /* 首页移动端顺序：公告摘要 → 热帖列表 → 版块卡片 */
  .home-columns {
    display: flex;
    flex-direction: column;
    gap: 16px;
  }

  .notice-sidebar {
    order: -1;
  }

  .hot-threads {
    order: 0;
  }

  .board-cards {
    order: 1;
  }

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

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

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

  .topic-cover {
    height: 180px;
  }

  /* 内页移动端布局 */
  .page-layout {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    order: 2;
  }

  .content-area {
    order: 1;
  }

  .layout-shell {
    flex-direction: column;
  }

  .main-content {
    width: 100%;
  }

  .sidebar-left {
    flex-direction: column;
  }

  .guide-index,
  .phase-aside {
    width: 100%;
    position: static;
    order: 2;
  }

  .guide-content,
  .rules-content-wrap {
    order: 1;
    width: 100%;
  }

  .archive-sidebar,
  .plan-sidebar,
  .feedback-sidebar {
    width: 100%;
  }

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

  .board-media {
    height: 160px;
  }

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

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

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

  .participate-content {
    grid-template-columns: 1fr;
  }

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

  .topic-thumb {
    height: 140px;
  }

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

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
}

@media (max-width: 480px) {
  .board-card-grid {
    grid-template-columns: 1fr;
  }

  .hero-figure {
    height: 200px;
  }

  .hero-content h1 {
    font-size: 24px;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .btn-primary,
  .btn-secondary {
    width: 100%;
  }

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

  .year-links {
    gap: 8px;
  }

  .year-link {
    padding: 6px 14px;
    font-size: 14px;
  }

  .hot-item {
    flex-direction: column;
    gap: 4px;
  }

  .hot-item a {
    min-width: 0;
  }

  .hot-entry {
    flex-direction: column;
    gap: 4px;
  }

  .hot-entry a {
    min-width: 0;
  }

  .archive-item {
    flex-direction: column;
    gap: 4px;
  }

  .archive-link {
    min-width: 0;
  }

  .topic-archive-item {
    flex-direction: column;
    gap: 4px;
  }

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