:root {
  --gold-900: #6f3d07;
  --gold-800: #8c560d;
  --gold-700: #ad741a;
  --gold-500: #d8a33d;
  --gold-300: #efd28d;
  --gold-200: #f6e5b6;
  --cream: #fffaf0;
  --paper: rgba(255, 252, 244, 0.92);
  --teal: #0d5866;
  --teal-deep: #064753;
  --shadow: 0 12px 30px rgba(116, 77, 14, 0.13);
  --soft-border: 1px solid rgba(190, 132, 34, 0.48);
  --radius: 18px;
  --content-width: 980px;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  scroll-behavior: smooth;
  background: #fff9e9;
}

body {
  min-height: 100%;
  margin: 0;
  color: var(--gold-900);
  font-family: "Noto Serif SC", "Songti SC", "STSong", "SimSun", serif;
  line-height: 1.6;
  background: transparent;
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

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

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.fixed-board {
  position: fixed;
  inset: 0;
  z-index: -2;
  overflow: hidden;
  background: #fff9e9;
  transform: translateZ(0);
  pointer-events: none;
}

.fixed-board::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: url("../images/background-board.png");
  background-position: center center;
  background-repeat: no-repeat;
  background-size: contain;
}

.fixed-board::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 50% 38%, rgba(255,255,255,0.18), rgba(255,255,255,0) 46%),
    linear-gradient(to bottom, rgba(255,255,255,0.02), rgba(255,250,235,0.08));
}


.site-shell {
  width: min(calc(100% - 32px), var(--content-width));
  margin: 0 auto;
  padding: 56px 0 80px;
}

.hero {
  text-align: center;
  margin-bottom: 32px;
  animation: fade-up 0.6s ease both;
}

.brand-title {
  margin: 0;
  font-size: clamp(3.1rem, 9vw, 6.8rem);
  line-height: 1.05;
  letter-spacing: 0.08em;
  color: transparent;
  background:
    linear-gradient(180deg, #f2d47c 0%, #b97b19 43%, #7c4507 72%, #d6a64d 100%);
  -webkit-background-clip: text;
  background-clip: text;
  filter: drop-shadow(0 4px 1px rgba(124, 69, 7, 0.11));
  font-family: "STKaiti", "KaiTi", "FangSong", serif;
  font-weight: 900;
}

.section-title {
  margin: 0;
  color: #4f2b08;
  font-size: clamp(2rem, 5.5vw, 3.8rem);
  line-height: 1.2;
  letter-spacing: 0.08em;
  text-shadow: 0 2px 0 rgba(255,255,255,0.75);
}

.section-subtitle {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin: 18px auto 0;
  font-size: clamp(1rem, 2.7vw, 1.35rem);
  font-weight: 700;
  letter-spacing: 0.08em;
  color: #84520e;
}

.section-subtitle::before,
.section-subtitle::after {
  content: "";
  width: min(18vw, 150px);
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--gold-500));
}

.section-subtitle::after {
  background: linear-gradient(90deg, var(--gold-500), transparent);
}

.department-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px 30px;
  margin-top: 36px;
}

.department-card {
  position: relative;
  min-height: 88px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px 56px 16px 24px;
  color: var(--teal-deep);
  background:
    linear-gradient(#fffdf8, #fffdf8) padding-box,
    linear-gradient(135deg, #f3d386, #b87918, #f3d386) border-box;
  border: 2px solid transparent;
  border-radius: 7px;
  box-shadow:
    0 8px 15px rgba(99, 66, 14, 0.13),
    inset 0 0 0 4px rgba(255, 247, 220, 0.88);
  font-family: "LiSu", "STLiti", "隶书", "SimLi", serif;
  font-size: clamp(1.28rem, 2.45vw, 1.72rem);
  font-weight: 400;
  letter-spacing: 0.08em;
  transition: transform 0.22s ease, box-shadow 0.22s ease, color 0.22s ease;
  animation: fade-up 0.55s ease both;
  animation-delay: var(--delay, 0ms);
}

.department-card::before,
.department-card::after {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  border-color: #c98c24;
  opacity: 0.7;
}

.department-card::before {
  left: 6px;
  top: 6px;
  border-left: 2px solid;
  border-top: 2px solid;
}

.department-card::after {
  right: 6px;
  bottom: 6px;
  border-right: 2px solid;
  border-bottom: 2px solid;
}

.department-card .arrow {
  position: absolute;
  right: 24px;
  top: 50%;
  transform: translateY(-52%);
  font-family: Arial, sans-serif;
  font-size: 2.1rem;
  font-weight: 300;
  line-height: 1;
  transition: transform 0.22s ease;
}

.department-card:hover,
.department-card:focus-visible {
  transform: translateY(-4px);
  color: #0b6c7b;
  box-shadow:
    0 14px 24px rgba(99, 66, 14, 0.18),
    inset 0 0 0 4px rgba(255, 247, 220, 0.95);
  outline: none;
}

.department-card:hover .arrow,
.department-card:focus-visible .arrow {
  transform: translate(5px, -52%);
}

.top-nav {
  width: min(calc(100% - 32px), var(--content-width));
  margin: 0 auto;
  padding-top: 22px;
  display: flex;
  justify-content: flex-start;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border: 1px solid rgba(179, 116, 21, 0.46);
  border-radius: 999px;
  color: var(--gold-800);
  background: rgba(255, 252, 244, 0.78);
  box-shadow: 0 6px 16px rgba(111, 61, 7, 0.09);
  backdrop-filter: blur(8px);
  font-size: 0.95rem;
  font-weight: 700;
  transition: transform 0.2s ease, background 0.2s ease;
}

.back-link:hover,
.back-link:focus-visible {
  transform: translateY(-2px);
  background: rgba(255, 255, 255, 0.96);
  outline: none;
}

.poster-list {
  display: grid;
  gap: 28px;
  margin-top: 32px;
}

.poster-card {
  overflow: hidden;
  border: var(--soft-border);
  border-radius: var(--radius);
  background: var(--paper);
  box-shadow: var(--shadow);
  backdrop-filter: blur(6px);
  animation: fade-up 0.65s ease both;
  animation-delay: var(--delay, 0ms);
}

.poster-image-link {
  position: relative;
  display: block;
  margin: 14px 14px 0;
  overflow: hidden;
  border-radius: 12px;
  background: #f4ead3;
  border: 1px solid rgba(194, 135, 33, 0.4);
}

.poster-image-link img {
  width: 100%;
  height: auto;
  transition: transform 0.5s ease, filter 0.5s ease;
}

.poster-hover {
  position: absolute;
  inset: auto 18px 18px auto;
  padding: 8px 16px;
  border-radius: 999px;
  color: #fff;
  background: rgba(76, 42, 5, 0.78);
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.25s ease, transform 0.25s ease;
  font-size: 0.92rem;
  letter-spacing: 0.06em;
}

.poster-image-link:hover img,
.poster-image-link:focus-visible img {
  transform: scale(1.018);
  filter: saturate(1.04);
}

.poster-image-link:hover .poster-hover,
.poster-image-link:focus-visible .poster-hover {
  opacity: 1;
  transform: translateY(0);
}

.poster-card-footer {
  padding: 14px 18px 20px;
  text-align: center;
}

.poster-card-footer h2 {
  margin: 0 0 10px;
  color: #6b400b;
  font-size: 1.35rem;
  letter-spacing: 0.16em;
}

.detail-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-width: 150px;
  padding: 8px 22px;
  border: 1px solid #d29a3a;
  border-radius: 999px;
  color: #8b5a12;
  background: rgba(255,255,255,0.72);
  font-weight: 700;
  letter-spacing: 0.08em;
  transition: transform 0.2s ease, color 0.2s ease, background 0.2s ease;
}

.detail-button:hover,
.detail-button:focus-visible {
  transform: translateY(-2px);
  color: #fff;
  background: #a66c15;
  outline: none;
}

.detail-layout {
  display: grid;
  gap: 22px;
  margin-top: 30px;
}

.detail-poster-frame,
.detail-info-card {
  border: var(--soft-border);
  border-radius: var(--radius);
  background: var(--paper);
  box-shadow: var(--shadow);
  backdrop-filter: blur(7px);
}

.detail-poster-frame {
  padding: 14px;
  overflow: hidden;
}

.detail-poster-frame img {
  width: 100%;
  height: auto;
  border-radius: 11px;
  border: 1px solid rgba(194, 135, 33, 0.36);
}

.detail-info-card {
  position: relative;
  padding: 28px 34px 34px;
}

.detail-info-card::before {
  content: "";
  position: absolute;
  left: 34px;
  right: 34px;
  top: 76px;
  border-top: 1px dashed rgba(174, 112, 22, 0.58);
}

.info-row {
  position: relative;
}

.author-line {
  margin: 0 0 40px;
  font-size: clamp(1.25rem, 3vw, 1.65rem);
  font-weight: 700;
  letter-spacing: 0.08em;
}

.idea-line {
  margin: 0;
  color: #6e430e;
  font-size: clamp(1.1rem, 2.7vw, 1.45rem);
  line-height: 2;
  text-align: justify;
  letter-spacing: 0.06em;
}

.info-label {
  color: #5a3108;
  font-weight: 900;
}

.page-kicker {
  margin-top: 12px;
  color: #a06a17;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.15em;
}

.back-to-top {
  position: fixed;
  right: 20px;
  bottom: 22px;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(175, 112, 19, 0.45);
  border-radius: 50%;
  color: #754608;
  background: rgba(255, 252, 244, 0.88);
  box-shadow: 0 8px 20px rgba(111, 61, 7, 0.16);
  backdrop-filter: blur(8px);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 0.2s ease, visibility 0.2s ease, transform 0.2s ease;
  z-index: 20;
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-3px);
}

.site-footer {
  margin: 40px 0 0;
  text-align: center;
  color: rgba(111, 61, 7, 0.68);
  font-size: 0.88rem;
  letter-spacing: 0.06em;
}

@keyframes fade-up {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 760px) {
  .site-shell {
    width: min(calc(100% - 24px), var(--content-width));
    padding-top: 34px;
  }

  .brand-title {
    letter-spacing: 0.03em;
  }

  .section-title {
    letter-spacing: 0.04em;
  }

  .section-subtitle {
    gap: 9px;
    letter-spacing: 0.04em;
  }

  .department-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
  }

  .department-card {
    min-height: 72px;
    padding: 12px 42px 12px 14px;
    font-size: 1.35rem;
    letter-spacing: 0.03em;
  }

  .department-card .arrow {
    right: 16px;
  }

  .poster-card {
    border-radius: 14px;
  }

  .poster-image-link {
    margin: 9px 9px 0;
  }

  .detail-info-card {
    padding: 24px 22px 28px;
  }

  .detail-info-card::before {
    left: 22px;
    right: 22px;
    top: 70px;
  }

  .idea-line {
    line-height: 1.85;
    letter-spacing: 0.03em;
  }
}

@media (max-width: 420px) {
  .department-grid {
    grid-template-columns: 1fr;
  }

  .department-card {
    min-height: 66px;
    font-size: 1.18rem;
  }

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

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}

/* ===== V4 WIDE LOCKED BOARD LAYOUT ===== */
:root {
  /*
   * 新版底板画幅为 1.05:1，较上一版明显加宽。
   * 底板和内容滚动区共用同一组尺寸，浏览器缩放时同步变化。
   */
  --board-aspect: 1.05;
  --board-render-width: min(100vw, calc(100vh * var(--board-aspect)));
  --board-render-height: calc(var(--board-render-width) / var(--board-aspect));
  --board-safe-width: calc(var(--board-render-width) * 0.84);
}

@supports (height: 100svh) {
  :root {
    --board-render-width: min(100vw, calc(100svh * var(--board-aspect)));
  }
}

html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
}

body {
  position: relative;
  background: #fff8e7;
}

/* 加宽底板与内容容器严格共用同一画幅。 */
.fixed-board {
  position: fixed;
  z-index: 0;
  inset: auto;
  left: 50%;
  top: 50%;
  width: var(--board-render-width);
  height: var(--board-render-height);
  overflow: hidden;
  transform: translate(-50%, -50%) translateZ(0);
  background: #fff9e9;
  box-shadow: 0 0 38px rgba(108, 69, 9, 0.12);
  pointer-events: none;
}

.fixed-board::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: url("../images/background-board-wide.png");
  background-position: center center;
  background-repeat: no-repeat;
  background-size: 100% 100%;
}

.fixed-board::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 50% 38%, rgba(255,255,255,0.16), rgba(255,255,255,0) 48%),
    linear-gradient(to bottom, rgba(255,255,255,0.02), rgba(255,250,235,0.07));
}

/* 内容只在底板内部滚动，任何浏览器缩放比例下都不会跑出底板。 */
.board-scroll {
  position: fixed;
  z-index: 1;
  left: 50%;
  top: 50%;
  width: var(--board-render-width);
  height: var(--board-render-height);
  overflow-x: hidden;
  overflow-y: auto;
  overscroll-behavior: contain;
  -webkit-overflow-scrolling: touch;
  transform: translate(-50%, -50%);
  scrollbar-width: none;
  outline: none;
}

.board-scroll::-webkit-scrollbar {
  width: 0;
  height: 0;
}

.site-shell,
.top-nav {
  width: var(--board-safe-width);
  max-width: none;
  margin-left: auto;
  margin-right: auto;
}

.site-shell {
  padding-top: clamp(28px, 4.8%, 54px);
  padding-bottom: clamp(44px, 7%, 82px);
}

.top-nav {
  padding-top: clamp(14px, 2.5%, 26px);
}

.hero {
  margin-bottom: clamp(20px, 3.5%, 34px);
}

/* 主要文字均跟随底板宽度同步缩放。 */
.brand-title {
  font-size: clamp(2.8rem, calc(var(--board-render-width) * 0.080), 6.1rem);
}

.section-title {
  font-size: clamp(1.9rem, calc(var(--board-render-width) * 0.043), 3.5rem);
}

.section-subtitle {
  gap: clamp(8px, calc(var(--board-render-width) * 0.012), 15px);
  margin-top: clamp(12px, calc(var(--board-render-width) * 0.016), 18px);
  font-size: clamp(0.96rem, calc(var(--board-render-width) * 0.0175), 1.32rem);
}

.section-subtitle::before,
.section-subtitle::after {
  width: calc(var(--board-render-width) * 0.12);
  max-width: 150px;
}

/* 首页部门区域：三列状态下保证所有名称单行显示。 */
.department-grid {
  gap:
    clamp(13px, calc(var(--board-render-width) * 0.015), 18px)
    clamp(16px, calc(var(--board-render-width) * 0.019), 22px);
  margin-top: clamp(24px, calc(var(--board-render-width) * 0.029), 34px);
}

.department-card {
  min-width: 0;
  min-height: clamp(78px, calc(var(--board-render-width) * 0.071), 92px);
  padding:
    clamp(12px, calc(var(--board-render-width) * 0.014), 17px)
    clamp(38px, calc(var(--board-render-width) * 0.040), 46px)
    clamp(12px, calc(var(--board-render-width) * 0.014), 17px)
    clamp(14px, calc(var(--board-render-width) * 0.018), 21px);
  font-family: "LiSu", "STLiti", "隶书", "SimLi", serif;
  font-size: clamp(1.55rem, calc(var(--board-render-width) * 0.033), 2.18rem);
  font-weight: 500;
  line-height: 1;
  letter-spacing: 0.03em;
  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.84);
}

.department-card.is-medium {
  letter-spacing: 0.022em;
}

.department-card.is-long {
  font-size: clamp(1.48rem, calc(var(--board-render-width) * 0.0305), 2.05rem);
  letter-spacing: 0.018em;
}

.department-name {
  display: block;
  min-width: 0;
  white-space: nowrap;
  word-break: keep-all;
  line-height: 1;
}

.department-card .arrow {
  right: clamp(12px, calc(var(--board-render-width) * 0.016), 19px);
  font-size: clamp(1.85rem, calc(var(--board-render-width) * 0.031), 2.35rem);
}

/* 二、三级页面内容同样限制在加宽底板的中央安全区。 */
.poster-list,
.detail-layout {
  width: 100%;
}

.poster-list {
  gap: clamp(20px, calc(var(--board-render-width) * 0.024), 28px);
  margin-top: clamp(24px, calc(var(--board-render-width) * 0.029), 34px);
}

.poster-card,
.detail-poster-frame,
.detail-info-card {
  width: 100%;
}

.poster-card-footer h2 {
  font-size: clamp(1.2rem, calc(var(--board-render-width) * 0.0215), 1.5rem);
}

.author-line {
  font-size: clamp(1.22rem, calc(var(--board-render-width) * 0.0235), 1.7rem);
}

.idea-line {
  font-size: clamp(1.05rem, calc(var(--board-render-width) * 0.0205), 1.45rem);
}

.page-kicker {
  font-size: clamp(0.92rem, calc(var(--board-render-width) * 0.016), 1.08rem);
}

/* 返回顶部按钮固定在加宽底板右下角内。 */
.back-to-top {
  right: calc((100vw - var(--board-render-width)) / 2 + 16px);
  bottom: calc((100vh - var(--board-render-height)) / 2 + 16px);
}

@supports (height: 100svh) {
  .back-to-top {
    bottom: calc((100svh - var(--board-render-height)) / 2 + 16px);
  }
}

/*
 * 中等宽度浏览器使用双列，进一步给部门名称留出空间。
 */
@media (max-width: 1100px) {
  :root {
    --board-safe-width: calc(var(--board-render-width) * 0.86);
  }

  .department-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 13px 18px;
  }
}

/*
 * 浏览器继续放大或在手机端打开时切换为单列，
 * 保证部门名称始终不换行。
 */
@media (max-width: 760px) {
  :root {
    --board-safe-width: calc(var(--board-render-width) * 0.86);
  }

  .site-shell {
    padding-top: clamp(22px, 4.5%, 36px);
  }

  .department-grid {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .department-card,
  .department-card.is-long {
    min-height: 74px;
    padding-left: 20px;
    padding-right: 50px;
    font-size: clamp(1.58rem, calc(var(--board-render-width) * 0.052), 1.95rem);
    letter-spacing: 0.055em;
  }
}

/* ===== V4 WIDE BOARD AND NO-WRAP DEPARTMENTS ===== */
:root {
  /*
   * 桌面端将底板由原来的竖向 3:4 画幅横向扩展为约 1.14:1。
   * 内容区与底板继续共用同一尺寸，因此缩放时仍保持同步。
   */
  --board-wide-ratio: 1.14;
  --board-render-width: min(96vw, calc(100vh * var(--board-wide-ratio)));
  --board-render-height: calc(var(--board-render-width) / var(--board-wide-ratio));
  --board-safe-width: calc(var(--board-render-width) * 0.88);
}

@supports (height: 100svh) {
  :root {
    --board-render-width: min(96vw, calc(100svh * var(--board-wide-ratio)));
  }
}

/* 横向加宽后的底板仍与内容区域完全重合。 */
.fixed-board,
.board-scroll {
  width: var(--board-render-width);
  height: var(--board-render-height);
}

/* 首页内容区域适当向两侧展开，整体更舒展。 */
.site-shell,
.top-nav {
  width: var(--board-safe-width);
}

.department-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  column-gap: clamp(16px, calc(var(--board-render-width) * 0.020), 26px);
  row-gap: clamp(13px, calc(var(--board-render-width) * 0.015), 20px);
}

.department-card {
  min-width: 0;
  min-height: clamp(82px, calc(var(--board-render-width) * 0.072), 98px);
  padding:
    clamp(14px, calc(var(--board-render-width) * 0.015), 18px)
    clamp(40px, calc(var(--board-render-width) * 0.043), 52px)
    clamp(14px, calc(var(--board-render-width) * 0.015), 18px)
    clamp(14px, calc(var(--board-render-width) * 0.018), 22px);
  font-family: "LiSu", "STLiti", "隶书", "SimLi", serif;
  font-size: clamp(1.68rem, calc(var(--board-render-width) * 0.032), 2.24rem);
  font-weight: 500;
  line-height: 1;
  letter-spacing: 0.035em;
  white-space: nowrap;
  word-break: keep-all;
  overflow: hidden;
}

.department-name {
  display: block;
  max-width: 100%;
  white-space: nowrap;
  word-break: keep-all;
  text-wrap: nowrap;
}

.department-card .arrow {
  right: clamp(13px, calc(var(--board-render-width) * 0.016), 20px);
  font-size: clamp(1.9rem, calc(var(--board-render-width) * 0.034), 2.4rem);
}

/* 桌面常见高度较小时仍保证长部门名称单行显示。 */
@media (min-width: 761px) and (max-height: 820px) {
  .department-card {
    min-height: 78px;
    padding-left: 14px;
    padding-right: 40px;
    font-size: clamp(1.62rem, calc(var(--board-render-width) * 0.031), 1.92rem);
    letter-spacing: 0.025em;
  }

  .department-grid {
    column-gap: 16px;
  }
}

/* 手机端恢复更适合竖屏的底板比例，并继续保持部门名称单行。 */
@media (max-width: 760px) {
  :root {
    --board-wide-ratio: 0.80;
    --board-render-width: min(100vw, calc(100svh * var(--board-wide-ratio)));
    --board-render-height: calc(var(--board-render-width) / var(--board-wide-ratio));
    --board-safe-width: calc(var(--board-render-width) * 0.84);
  }

  .department-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 12px;
  }

  .department-card {
    min-height: 76px;
    padding-left: 12px;
    padding-right: 36px;
    font-size: clamp(1.35rem, calc(var(--board-render-width) * 0.053), 1.72rem);
    letter-spacing: 0.02em;
  }

  .department-card .arrow {
    right: 12px;
  }
}

@media (max-width: 520px) {
  .department-grid {
    grid-template-columns: 1fr;
  }

  .department-card {
    min-height: 74px;
    padding-left: 18px;
    padding-right: 42px;
    font-size: clamp(1.62rem, calc(var(--board-render-width) * 0.068), 1.95rem);
    letter-spacing: 0.055em;
  }
}