/* =====================================================
   醫院 40 周年慶大事記網頁
   全站樣式表 — css/style.css
   色彩規範：
     主色 (信任藍) #005689
     輔助色 (慶典金) #C5A059
   斷點：
     桌機 ≥ 1024px | 平板 768–1023px | 手機 < 768px
===================================================== */


/* =====================================================
   1. CSS 自訂變數 (Design Tokens)
===================================================== */
:root {
  /* 品牌色 */
  --color-primary:       #005689;  /* 信任藍 */
  --color-primary-dark:  #003f66;  /* 深藍（hover / Header scrolled）*/
  --color-gold:          #C5A059;  /* 慶典金 */
  --color-gold-dark:     #a8844a;  /* 深金（hover）*/

  /* 中性色 */
  --color-white:         #ffffff;
  --color-bg:            #f7f9fb;  /* 頁面淺灰背景 */
  --color-bg-alt:        #eef2f7;  /* 交錯 section 背景 */
  --color-text:          #1a2733;  /* 主文字深藍黑 */
  --color-text-muted:    #5a6e7f;  /* 次要文字 */

  /* 陰影（微陰影，增加層次感）*/
  --shadow-sm:  0 2px  8px rgba(0, 0, 0, .08);
  --shadow-md:  0 4px 20px rgba(0, 0, 0, .12);
  --shadow-lg:  0 8px 40px rgba(0, 0, 0, .16);

  /* 排版 */
  --font-base:  'Noto Sans TC', 'Microsoft JhengHei', sans-serif;
  --size-base:  16px;
  --lh-base:    1.75;

  /* 動畫 */
  --transition-base: 0.3s ease;

  /* Header 高度（用於 scroll-padding）*/
  --header-h: 64px;
}


/* =====================================================
   2. Reset & Base
===================================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: var(--size-base);
  scroll-behavior: smooth;
  /* 讓固定 Header 不遮住錨點目標 */
  scroll-padding-top: var(--header-h);
}

body {
  font-family: var(--font-base);
  font-size: 1rem;
  line-height: var(--lh-base);
  color: var(--color-text);
  background-color: var(--color-bg);
}

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

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

ul {
  list-style: none;
}


/* =====================================================
   3. 工具類別
===================================================== */

/* 限制最大寬度並水平置中 */
.container {
  width: 100%;
  max-width: 1140px;
  margin-inline: auto;
  padding-inline: 1.5rem;
}

/* Section 共用上下間距 */
.section {
  padding-block: 5rem;
}

.section--alt {
  background-color: var(--color-bg-alt);
}

/* Section 標題組 */
.section-title {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 700;
  color: var(--color-primary);
  text-align: center;
  letter-spacing: .05em;
}

.section-subtitle {
  margin-top: .5rem;
  font-size: 1rem;
  color: var(--color-gold);
  text-align: center;
  letter-spacing: .15em;
  text-transform: uppercase;
}


/* =====================================================
   4. 按鈕元件
===================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;       /* 觸控友善：最小 44px */
  padding: .75rem 2rem;
  border-radius: 4px;
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: .05em;
  cursor: pointer;
  transition: background-color var(--transition-base),
              color var(--transition-base),
              box-shadow var(--transition-base);
  border: 2px solid transparent;
}

/* 金色實心按鈕（主要 CTA）*/
.btn--gold {
  background-color: var(--color-gold);
  color: var(--color-white);
  border-color: var(--color-gold);
}
.btn--gold:hover,
.btn--gold:focus-visible {
  background-color: var(--color-gold-dark);
  border-color: var(--color-gold-dark);
  box-shadow: var(--shadow-md);
}

/* 藍色外框按鈕（次要）*/
.btn--outline {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.btn--outline:hover,
.btn--outline:focus-visible {
  background-color: var(--color-primary);
  color: var(--color-white);
}

/* 大尺寸修飾 */
.btn--lg {
  padding: 1rem 2.5rem;
  font-size: 1.125rem;
}


/* =====================================================
   5. Step 2｜Header
===================================================== */
#site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-h);
  /* 預設透明；捲動後 JS 加上 .scrolled，背景變深藍 */
  background-color: transparent;
  transition: background-color var(--transition-base),
              box-shadow var(--transition-base);
}

#site-header.scrolled {
  background-color: var(--color-primary-dark);
  box-shadow: var(--shadow-md);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

/* Logo */
.site-logo {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
  color: var(--color-white);
}

.logo-name {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: .05em;
}

.logo-badge {
  font-size: .75rem;
  color: var(--color-gold);
  letter-spacing: .1em;
}

/* 主導覽 */
.main-nav ul {
  display: flex;
  gap: 2rem;
}

.main-nav a {
  color: var(--color-white);
  font-weight: 500;
  font-size: .95rem;
  letter-spacing: .05em;
  padding-block: .25rem;
  position: relative;
}

/* 底線懸停效果 */
.main-nav a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-gold);
  transition: width var(--transition-base);
}
.main-nav a:hover::after,
.main-nav a:focus-visible::after {
  width: 100%;
}

/* 漢堡按鈕（手機用；桌機隱藏）*/
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: .5rem;
  min-height: 44px;
  min-width: 44px;
  align-items: center;
  justify-content: center;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-white);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}


/* =====================================================
   6. Step 2｜Hero Section
===================================================== */
#hero {
  position: relative;
  min-height: 100svh;       /* 視口高度，使用 svh 支援行動瀏覽器工具列 */
  display: flex;
  align-items: center;
  overflow: hidden;
}

/* 全幅背景圖 */
.hero-bg-picture {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hero-bg-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  /* 尚未置入實際圖片時，以漸層色塊替代 */
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 60%, #007ab8 100%);
}

/* 深色遮罩，確保文字在任何背景圖上均清晰 */
.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    to bottom,
    rgba(0, 31, 55, .55) 0%,
    rgba(0, 31, 55, .70) 60%,
    rgba(0, 31, 55, .85) 100%
  );
}

/* Hero 文字內容 */
.hero-content {
  position: relative;   /* 疊在遮罩之上 */
  z-index: 1;
  color: var(--color-white);
  text-align: center;
  padding-top: var(--header-h); /* 避免被固定 Header 遮住 */
}

.hero-eyebrow {
  font-size: .9rem;
  letter-spacing: .25em;
  color: var(--color-gold);
  text-transform: uppercase;
  margin-bottom: 1rem;
}

.hero-title {
  font-size: clamp(2.25rem, 6vw, 4.5rem);
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: .08em;
  text-shadow: 0 2px 12px rgba(0, 0, 0, .4);
  margin-bottom: 1.5rem;
}

.hero-desc {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: rgba(255, 255, 255, .85);
  max-width: 520px;
  margin-inline: auto;
  margin-bottom: 2.5rem;
}

/* 向下捲動箭頭 */
.scroll-hint {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
}

.scroll-hint__arrow {
  display: block;
  width: 20px;
  height: 20px;
  border-right: 2px solid var(--color-gold);
  border-bottom: 2px solid var(--color-gold);
  transform: rotate(45deg);
  animation: bounce-down 1.6s ease-in-out infinite;
}

@keyframes bounce-down {
  0%, 100% { transform: rotate(45deg) translateY(0);    opacity: 1; }
  50%       { transform: rotate(45deg) translateY(6px);  opacity: .6; }
}


/* =====================================================
   7. Step 3｜Timeline Section
===================================================== */
#timeline .section-title {
  margin-bottom: .5rem;
}

/* ── 軌道容器：相對定位，以便繪製中軸線 ── */
.timeline {
  position: relative;
  margin-top: 4rem;
  padding-block: 1rem;
}

/* 中軸線（信任藍漸層，兩端淡出）*/
.timeline::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 3px;
  background: linear-gradient(
    to bottom,
    transparent 0%,
    var(--color-primary) 6%,
    var(--color-primary) 94%,
    transparent 100%
  );
}

/* ── 每個年份項目：3 欄 grid（左卡 ｜ 軸心 ｜ 右卡）── */
.timeline-item {
  display: grid;
  grid-template-columns: 1fr 100px 1fr;
  align-items: start;
  margin-bottom: 4rem;
  gap: 0 1.5rem;
}

.timeline-item:last-child {
  margin-bottom: 0;
}

/* 奇數項：卡片在右欄 */
.timeline-item:nth-child(odd) .timeline-axis { grid-column: 2; grid-row: 1; }
.timeline-item:nth-child(odd) .timeline-card { grid-column: 3; grid-row: 1; }

/* 偶數項：卡片在左欄，軸心仍在中間 */
.timeline-item:nth-child(even) .timeline-card { grid-column: 1; grid-row: 1; }
.timeline-item:nth-child(even) .timeline-axis { grid-column: 2; grid-row: 1; }

/* ── 軸心：年份徽章容器 ── */
.timeline-axis {
  display: flex;
  justify-content: center;
  padding-top: 1.5rem;   /* 對齊卡片標題高度 */
  position: relative;
  z-index: 1;            /* 疊在中軸線之上 */
}

/* 年份圓形徽章（信任藍）*/
.timeline-year-badge {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 68px;
  height: 68px;
  border-radius: 50%;
  background-color: var(--color-primary);
  color: var(--color-white);
  font-size: .9rem;
  font-weight: 700;
  letter-spacing: .03em;
  /* 雙層光暈：白環 + 藍環，製造浮雕感 */
  box-shadow:
    0 0 0 5px var(--color-bg),
    0 0 0 8px var(--color-primary),
    var(--shadow-sm);
}

/* 40 周年高亮版本（慶典金）*/
.timeline-year-badge--highlight {
  background-color: var(--color-gold);
  box-shadow:
    0 0 0 5px var(--color-bg),
    0 0 0 8px var(--color-gold),
    var(--shadow-sm);
}

/* ── 卡片 ── */
.timeline-card {
  background-color: var(--color-white);
  border-radius: 10px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.timeline-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

/* 40 周年卡片：頂部金色邊條強調 */
.timeline-card--highlight {
  border-top: 4px solid var(--color-gold);
}

/* 卡片圖片區（16:9 比例，無圖時顯示淺灰底）*/
.timeline-card__img-wrap {
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background-color: var(--color-bg-alt);
}

.timeline-card__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .5s ease;
}

.timeline-card:hover .timeline-card__img {
  transform: scale(1.05);
}

/* 卡片文字區 */
.timeline-card__body {
  padding: 1.5rem;
}

/* 標籤（信任藍）*/
.timeline-card__tag {
  display: inline-block;
  padding: .2rem .75rem;
  border-radius: 2px;
  background-color: var(--color-primary);
  color: var(--color-white);
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .1em;
  margin-bottom: .75rem;
}

/* 標籤（慶典金：40 周年用）*/
.timeline-card__tag--gold {
  background-color: var(--color-gold);
}

/* 卡片標題 */
.timeline-card__title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.45;
  margin-bottom: .75rem;
}

/* 卡片內文 */
.timeline-card__text {
  font-size: .95rem;
  color: var(--color-text-muted);
  line-height: 1.85;
}


/* =====================================================
   8. Timeline Accordion（折疊式時間軸）
===================================================== */

.timeline-accordion {
  margin-top: 3rem;
  border: 1px solid #dde6ef;
  border-radius: 10px;
  overflow: hidden;
}

/* 每個年代區塊 */
.tl-era {
  border-bottom: 1px solid #dde6ef;
}
.tl-era:last-child {
  border-bottom: none;
}

/* 年代標題按鈕 */
.tl-era__header {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.25rem 1.5rem;
  background: var(--color-white);
  border: none;
  cursor: pointer;
  text-align: left;
  transition: background var(--transition-base);
  min-height: 44px;
}

.tl-era__header:hover,
.tl-era.is-open .tl-era__header {
  background: var(--color-bg-alt);
}

.tl-era__label {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--color-primary);
  flex: 1;
}

.tl-era__range {
  font-size: .875rem;
  color: var(--color-text-muted);
}

.tl-era__count {
  font-size: .78rem;
  background: var(--color-bg);
  border: 1px solid #dde6ef;
  padding: .2rem .65rem;
  border-radius: 20px;
  color: var(--color-text-muted);
  white-space: nowrap;
}

/* 展開箭頭 */
.tl-era__arrow {
  flex-shrink: 0;
  width: 9px;
  height: 9px;
  border-right: 2px solid var(--color-primary);
  border-bottom: 2px solid var(--color-primary);
  transform: rotate(45deg);
  transition: transform var(--transition-base);
  margin-left: .25rem;
}

.tl-era.is-open .tl-era__arrow {
  transform: rotate(-135deg);
}

/* 折疊主體：預設收合 */
.tl-era__body {
  max-height: 0;
  overflow: hidden;
  transition: max-height .4s ease;
}

.tl-era.is-open .tl-era__body {
  max-height: 2000px;
}

/* 里程碑列表 */
.tl-era__list {
  padding: .5rem 1.5rem 1.25rem 2.75rem; /* 左側多留空間給線條與圓點 */
  border-top: 1px solid #dde6ef;
  position: relative;
}

/* 左側垂直連接線：展開時從上往下繪製 */
.tl-era__list::before {
  content: '';
  position: absolute;
  left: 1.75rem;
  top: .75rem;
  bottom: .75rem;
  width: 2px;
  background: linear-gradient(
    to bottom,
    var(--color-primary) 0%,
    rgba(0, 86, 137, .2) 100%
  );
  transform: scaleY(0);
  transform-origin: top;
  transition: transform .45s ease;
}

.tl-era.is-open .tl-era__list::before {
  transform: scaleY(1);
}

/* 單一里程碑列項 */
.tl-milestone {
  display: flex;
  align-items: flex-start;
  gap: 1.25rem;
  padding: 1rem 0;
  border-bottom: 1px solid #eef2f7;
}

.tl-milestone:last-child {
  border-bottom: none;
}

/* 年份欄 */
.tl-milestone__year {
  flex-shrink: 0;
  min-width: 44px;
  font-size: .85rem;
  font-weight: 700;
  color: var(--color-primary);
  padding-top: .15rem;
  letter-spacing: .03em;
  position: relative;
}

/* 年份圓點，對齊左側連接線 */
.tl-milestone__year::before {
  content: '';
  position: absolute;
  left: -1.25rem;
  top: .55rem;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background-color: var(--color-primary);
  border: 2px solid var(--color-white);
  box-shadow: 0 0 0 2px var(--color-primary);
  z-index: 1;
}

.tl-milestone__year--gold {
  color: var(--color-gold);
}

.tl-milestone--highlight .tl-milestone__year::before {
  background-color: var(--color-gold);
  box-shadow: 0 0 0 2px var(--color-gold);
}

/* 文字區 */
.tl-milestone__content {
  flex: 1;
}

.tl-milestone__title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: .35rem;
  line-height: 1.45;
}

.tl-milestone__text {
  font-size: .9rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* 縮圖（可選，有圖片才顯示）*/
.tl-milestone__img-wrap {
  flex-shrink: 0;
}

.tl-milestone__img {
  width: 120px;
  height: 80px;
  object-fit: cover;
  border-radius: 6px;
  display: block;
}

/* 40周年高亮列項 */
.tl-milestone--highlight .tl-milestone__title {
  color: var(--color-gold);
}

/* ── RWD：手機版 ── */
@media (max-width: 767px) {
  .tl-era__header {
    flex-wrap: wrap;
    gap: .5rem;
    padding: 1rem;
  }

  .tl-era__range {
    order: 3;
    font-size: .8rem;
  }

  .tl-era__count {
    order: 4;
  }

  .tl-era__arrow {
    order: 2;
  }

  .tl-era__list {
    padding: .5rem 1rem 1rem;
  }

  .tl-milestone {
    flex-wrap: wrap;
    gap: .75rem;
  }

  .tl-milestone__img-wrap {
    order: -1;
    width: 100%;
  }

  .tl-milestone__img {
    width: 100%;
    height: 160px;
  }
}


/* =====================================================
   9. Step 5｜Flipbook Section
===================================================== */

/* Section 背景：規格書指定的優雅淺灰 */
#flipbook {
  background-color: #F8F9FA;
}

/* 翻頁書整體包裝：統一圓角與陰影 */
.flipbook-wrap {
  margin-top: 2.5rem;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  background-color: #F8F9FA;
}

/* ── 觸發區（點擊前）── */
.flipbook-trigger {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2rem;
  min-height: 300px;
  padding: 3rem 2rem;
  background: linear-gradient(145deg, #eef2f7 0%, #e4ecf4 100%);
  border: 2px dashed #c0d0df;
  border-radius: 12px;
  text-align: center;
}

.flipbook-cover-hint {
  color: var(--color-text-muted);
}

.flipbook-cover-hint svg {
  width: 72px;
  height: 72px;
  margin-inline: auto;
  margin-bottom: .75rem;
  opacity: .45;
}

.flipbook-cover-hint p {
  font-size: .95rem;
  letter-spacing: .03em;
}

/* ── 載入動畫（點擊後、DearFlip 就緒前）── */
.flipbook-loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  min-height: 300px;
  color: var(--color-text-muted);
  font-size: .95rem;
}

/* CSS 旋轉環形動畫 */
.flipbook-spinner {
  width: 52px;
  height: 52px;
  border: 5px solid #dde5ee;
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: flipbook-spin .85s linear infinite;
}

@keyframes flipbook-spin {
  to { transform: rotate(360deg); }
}

/* ── DearFlip 翻頁書容器 ── */
/* 桌機固定 600px；手機版由 RWD 區塊控制 */
.flipbook-container {
  width: 100%;
  height: 600px;
}

/* ── 下載按鈕（桌機版，翻頁書下方）── */
.flipbook-actions {
  margin-top: 1.5rem;
  text-align: center;
}

/* ── 手機版備用下載區塊（桌機隱藏）── */
.flipbook-mobile-fallback {
  display: none;
  text-align: center;
  margin-top: 2rem;
}

.flipbook-mobile-fallback p {
  margin-bottom: 1rem;
  color: var(--color-text-muted);
  font-size: .95rem;
}


/* =====================================================
   9. 導讀播放器
===================================================== */
.podcast-player {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin: 2rem auto 0;
  max-width: 640px;
  background: var(--color-white);
  border: 1px solid #dde5ee;
  border-radius: 12px;
  padding: 1.25rem 1.5rem;
  box-shadow: var(--shadow-sm);
}

.podcast-player__info {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.podcast-player__icon {
  font-size: 2rem;
  line-height: 1;
}

.podcast-player__title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-primary);
}

.podcast-player__desc {
  font-size: .85rem;
  color: var(--color-text-muted);
  margin-top: .2rem;
}

.podcast-player__audio {
  width: 100%;
  accent-color: var(--color-primary);
}


/* =====================================================
   11. 歲月留影 Section
===================================================== */
#history .section-title { margin-bottom: .5rem; }

.history-hint {
  text-align: center;
  font-size: .875rem;
  color: var(--color-text-muted);
  margin-top: .75rem;
  letter-spacing: .05em;
}

.history-strip-wrap {
  margin-top: 2.5rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
  scrollbar-color: var(--color-primary) transparent;
}

.history-strip-wrap::-webkit-scrollbar { height: 6px; }
.history-strip-wrap::-webkit-scrollbar-thumb {
  background: var(--color-primary);
  border-radius: 3px;
}

.history-strip {
  display: flex;
  align-items: flex-end;
  gap: 1rem;
  padding: 1rem 2rem 1.5rem;
  scroll-snap-type: x mandatory;
  width: max-content;
}

.history-year-flag {
  flex-shrink: 0;
  align-self: flex-end;
  padding: .4rem .9rem;
  background: var(--color-primary);
  color: var(--color-white);
  font-size: .85rem;
  font-weight: 700;
  letter-spacing: .1em;
  border-radius: 4px;
  margin-bottom: .25rem;
}

.history-item {
  flex-shrink: 0;
  width: 240px;
  scroll-snap-align: start;
  cursor: zoom-in;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform .25s ease, box-shadow .25s ease;
  margin: 0;
}

.history-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.history-item img {
  display: block;
  width: 100%;
  height: 180px;
  object-fit: cover;
}

/* ── 燈箱 ── */
.history-lightbox {
  position: fixed;
  inset: 0;
  z-index: 200;
  background: rgba(0, 0, 0, .92);
  display: flex;
  align-items: center;
  justify-content: center;
}

.history-lightbox[hidden] { display: none; }

.history-lb__figure {
  max-width: 90vw;
  max-height: 90vh;
  margin: 0;
  text-align: center;
}

.history-lb__figure img {
  max-width: 100%;
  max-height: 85vh;
  object-fit: contain;
  border-radius: 4px;
}

.history-lb__figure figcaption {
  margin-top: .75rem;
  color: rgba(255, 255, 255, .6);
  font-size: .875rem;
  letter-spacing: .05em;
}

.history-lb__close,
.history-lb__prev,
.history-lb__next {
  position: absolute;
  background: none;
  border: none;
  color: var(--color-white);
  font-size: 2.5rem;
  cursor: pointer;
  padding: .5rem 1rem;
  opacity: .75;
  transition: opacity .2s;
  line-height: 1;
}

.history-lb__close:hover,
.history-lb__prev:hover,
.history-lb__next:hover { opacity: 1; }

.history-lb__close { top: 1rem;  right: 1.5rem; font-size: 1.5rem; }
.history-lb__prev  { left: 1rem; top: 50%; transform: translateY(-50%); }
.history-lb__next  { right: 1rem; top: 50%; transform: translateY(-50%); }

@media (max-width: 767px) {
  .history-item       { width: 180px; }
  .history-item img   { height: 140px; }
}


/* =====================================================
   10. 歷年典藏特刊 Section
===================================================== */
.archive-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
  margin-top: 3rem;
}

.archive-card {
  background: var(--color-white);
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: box-shadow var(--transition-base), transform var(--transition-base);
}

.archive-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}

.archive-card__cover {
  aspect-ratio: 3 / 4;
  overflow: hidden;
}

.archive-card__cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .4s ease;
}

.archive-card:hover .archive-card__cover img {
  transform: scale(1.04);
}

.archive-card__body {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: .75rem;
}

.archive-card__year {
  font-size: .85rem;
  color: var(--color-gold);
  font-weight: 600;
  letter-spacing: .1em;
}

.archive-card__title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1.4;
}


/* =====================================================
   10. Footer
===================================================== */
#site-footer {
  background-color: var(--color-primary-dark);
  color: rgba(255, 255, 255, .7);
  text-align: center;
  padding-block: 1.5rem;
  font-size: .875rem;
  letter-spacing: .05em;
}


/* =====================================================
   10. 捲動觸發動畫（IntersectionObserver 驅動）
       JS 將為可見元素加上 .is-visible class
===================================================== */
.fade-up {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity .6s ease, transform .6s ease;
}

.fade-up.is-visible {
  opacity: 1;
  transform: translateY(0);
}


/* =====================================================
   11. RWD 斷點 — 平板 (768px – 1023px)
===================================================== */
@media (max-width: 1023px) {
  .section {
    padding-block: 4rem;
  }

  /* Timeline：縮小軸心欄寬 */
  .timeline-item {
    grid-template-columns: 1fr 80px 1fr;
    gap: 0 1rem;
    margin-bottom: 3rem;
  }

  .timeline-year-badge {
    width: 58px;
    height: 58px;
    font-size: .8rem;
  }
}


/* =====================================================
   12. RWD 斷點 — 手機 (< 768px)
===================================================== */
@media (max-width: 767px) {

  /* Header：顯示漢堡鈕，隱藏橫向導覽 */
  .nav-toggle {
    display: flex;
  }

  .main-nav {
    display: none;           /* 收合；JS 加 .nav-open 展開 */
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    background-color: var(--color-primary-dark);
    padding: 1.5rem;
    box-shadow: var(--shadow-lg);
  }

  .main-nav.nav-open {
    display: block;
  }

  .main-nav ul {
    flex-direction: column;
    gap: 0;
  }

  .main-nav a {
    display: block;
    padding-block: .875rem;
    border-bottom: 1px solid rgba(255, 255, 255, .1);
    font-size: 1rem;
  }

  /* ── Timeline：單欄靠左排列 ── */
  /* 軸線移到最左側 */
  .timeline::before {
    left: 24px;
    transform: none;
  }

  /* 所有項目改為 2 欄（軸心 | 卡片），消除左右交錯 */
  .timeline-item {
    grid-template-columns: 48px 1fr;
    margin-bottom: 2rem;
    gap: 0 1rem;
  }

  /* 不分奇偶，軸心固定第 1 欄，卡片固定第 2 欄 */
  .timeline-item:nth-child(odd)  .timeline-axis,
  .timeline-item:nth-child(even) .timeline-axis {
    grid-column: 1;
    grid-row: 1;
  }

  .timeline-item:nth-child(odd)  .timeline-card,
  .timeline-item:nth-child(even) .timeline-card {
    grid-column: 2;
    grid-row: 1;
  }

  .timeline-axis {
    padding-top: 1rem;
  }

  .timeline-year-badge {
    width: 46px;
    height: 46px;
    font-size: .7rem;
    box-shadow:
      0 0 0 3px var(--color-bg),
      0 0 0 5px var(--color-primary);
  }

  .timeline-year-badge--highlight {
    box-shadow:
      0 0 0 3px var(--color-bg),
      0 0 0 5px var(--color-gold);
  }

  /* Hero：行動裝置文字左對齊，提升閱讀舒適度 */
  .hero-content {
    text-align: left;
  }

  .hero-desc {
    margin-inline: 0;
  }

  .section {
    padding-block: 3rem;
  }

  /* Flipbook：手機版隱藏翻頁器，改顯示下載按鈕 */
  .flipbook-wrap,
  .flipbook-actions {
    display: none;
  }

  .flipbook-mobile-fallback {
    display: block;
  }

  /* 若日後開放手機版翻頁書，容器改為自動高度 */
  .flipbook-container {
    height: auto;
    min-height: 420px;
  }

  /* 典藏特刊：單欄置中 */
  .archive-grid {
    grid-template-columns: 1fr;
    max-width: 360px;
    margin-inline: auto;
  }
}