/* ==========================================================================
   DeepSeek · 古航海图视觉体系 (Carta Marina & Portolan Chart)
   设计风格：
   羊皮纸、罗盘玫瑰、海怪微饰与清晰数据区。
   API 开放平台像港口税则，DeepSeek 书于古典图题（Cartouche），
   未探海域留白并标明「未至之境 / Terra Incognita」。
   航线恒向线（Rhumb lines）交错织网，象征深度逻辑推理推演路径。
   ========================================================================== */

:root {
  /* 古航海图调色盘 */
  --parchment-base: #F8F4EC;         /* 羊皮纸古典暖白 */
  --parchment-warm: #F2ECE0;         /* 羊皮纸阴影层 */
  --parchment-border: #E0D5C1;       /* 羊皮纸边缘蚀刻线 */
  --nautical-navy: #183A53;          /* 大航海深海深蓝（品牌主色） */
  --nautical-navy-hover: #102738;
  --compass-bronze: #A86B32;         /* 航海铜盘金（强调辅色） */
  --compass-red: #A8332A;            /* 航海图注朱砂红 */
  --ink-primary: #25201A;            /* 航海图墨汁主字色 */
  --ink-secondary: #5C5245;          /* 航次说明次级字色 */
  --ink-subtle: #8A7F70;             /* 经纬度弱化字色 */
  
  /* 映射至全局规范变量 */
  --color-brand: var(--nautical-navy);
  --color-brand-hover: var(--nautical-navy-hover);
  --color-accent: var(--compass-bronze);
  --color-paper: var(--parchment-base);
  --color-paper-alt: var(--parchment-warm);
  --color-card-border: var(--parchment-border);
  
  /* 圆角规范 */
  --radius-card: 12px;
  --radius-btn: 12px;
  --radius-brand-box: 8px;
  --radius-capsule: 9999px;

  /* 字体系统 */
  --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
  --font-mono: "Fira Code", "Cascadia Code", "JetBrains Mono", Consolas, "Courier New", monospace;
}

/* 全局重置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  background-color: var(--color-paper);
  color: var(--ink-primary);
}

body {
  font-family: var(--font-base);
  line-height: 1.7;
  background: var(--color-paper);
  color: var(--ink-primary);
  position: relative;
  overflow-x: hidden;
}

/* 航海图恒向线（Rhumb Lines）背景装饰 */
.rhumb-lines-bg {
  background-image: 
    radial-gradient(circle at 15% 30%, rgba(168, 107, 50, 0.05) 0%, transparent 40%),
    radial-gradient(circle at 85% 70%, rgba(24, 58, 83, 0.05) 0%, transparent 45%),
    linear-gradient(45deg, transparent 49.5%, rgba(168, 107, 50, 0.035) 50%, transparent 50.5%),
    linear-gradient(-45deg, transparent 49.5%, rgba(168, 107, 50, 0.035) 50%, transparent 50.5%);
  background-size: 100% 100%, 100% 100%, 360px 360px, 360px 360px;
}

/* 容器定义 */
.container {
  width: 100%;
  max-width: 1240px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 64px;
  padding-right: 64px;
}
@media (max-width: 968px) {
  .container {
    padding-left: 32px;
    padding-right: 32px;
  }
}
@media (max-width: 640px) {
  .container {
    padding-left: 16px;
    padding-right: 16px;
  }
}

.section-wrapper {
  padding-top: 100px;
  padding-bottom: 100px;
  position: relative;
}

/* 单一对齐轴：居中区 */
.section-header-center {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 56px auto;
}
.section-title-center {
  font-size: 38px;
  font-weight: 700;
  letter-spacing: -0.8px;
  color: var(--ink-primary);
  margin-bottom: 18px;
  line-height: 1.25;
}
.section-desc-center {
  font-size: 16px;
  color: var(--ink-secondary);
  line-height: 1.7;
}

/* 按钮体系：全页只有一个主按钮层级 */
.btn-primary-solid {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background-color: var(--color-brand);
  color: #FFFFFF;
  font-size: 14px;
  font-weight: 600;
  padding: 10px 24px;
  border-radius: var(--radius-btn);
  border: 1px solid var(--color-brand);
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
  white-space: nowrap;
}
.btn-primary-solid:hover {
  background-color: var(--color-brand-hover);
  border-color: var(--color-brand-hover);
  transform: translateY(-1px);
}

.btn-outline-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background-color: #FFFFFF;
  color: var(--ink-primary);
  font-size: 14px;
  font-weight: 500;
  padding: 10px 24px;
  border-radius: var(--radius-btn);
  border: 1px solid var(--parchment-border);
  text-decoration: none;
  cursor: pointer;
  transition: border-color 0.2s ease, background-color 0.2s ease;
  white-space: nowrap;
}
.btn-outline-secondary:hover {
  border-color: var(--color-brand);
  background-color: var(--parchment-base);
}

.btn-ghost-nav {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  color: var(--ink-secondary);
  font-size: 14px;
  font-weight: 500;
  padding: 8px 16px;
  border-radius: var(--radius-btn);
  border: none;
  text-decoration: none;
  transition: color 0.2s ease;
  cursor: pointer;
}
.btn-ghost-nav:hover {
  color: var(--color-brand);
}

/* ==========================================================================
   导航：固定在顶部，高 64px。白底约 80% 透明，背后模糊，底边一条极浅分割线
   ========================================================================== */
.navbar-fixed {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 64px;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(224, 213, 193, 0.7);
  z-index: 1000;
}
.navbar-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}
.nav-brand-logo {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-brand-box);
  object-fit: cover;
  border: 1px solid var(--parchment-border);
}
.nav-brand-text {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.5px;
  color: var(--ink-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}
.cartouche-tag {
  font-size: 11px;
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--compass-bronze);
  background: rgba(168, 107, 50, 0.1);
  padding: 2px 7px;
  border-radius: 4px;
  border: 1px solid rgba(168, 107, 50, 0.25);
  letter-spacing: 0.5px;
}

.nav-links-center {
  display: flex;
  align-items: center;
  gap: 36px;
}
.nav-link-item {
  font-size: 14px;
  color: var(--ink-secondary);
  text-decoration: none;
  font-weight: 400;
  transition: color 0.2s ease;
}
.nav-link-item:hover, .nav-link-item.active {
  color: var(--color-brand);
}

.nav-actions-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* 移动端菜单抽屉 */
.mobile-menu-btn {
  display: none;
  background: transparent;
  border: 1px solid var(--parchment-border);
  padding: 6px;
  border-radius: 6px;
  cursor: pointer;
  color: var(--ink-primary);
}
.mobile-menu-drawer {
  display: none;
  position: fixed;
  top: 64px;
  left: 0;
  right: 0;
  background: #FFFFFF;
  border-bottom: 1px solid var(--parchment-border);
  padding: 20px 32px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.06);
  z-index: 999;
}
.mobile-menu-drawer.open {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.mobile-nav-item {
  font-size: 15px;
  color: var(--ink-primary);
  text-decoration: none;
  padding: 8px 0;
  border-bottom: 1px dashed var(--parchment-border);
}

@media (max-width: 968px) {
  .nav-links-center { display: none; }
  .mobile-menu-btn { display: flex; align-items: center; }
}

/* ==========================================================================
   首屏：两列 1:1，间距 60px，上内边距约 140px，最小高度约一屏
   古航海图图题卷轴（Cartouche）风格
   ========================================================================== */
.hero-section {
  padding-top: 140px;
  padding-bottom: 90px;
  min-height: calc(100vh - 64px);
  display: flex;
  align-items: center;
  position: relative;
  background: linear-gradient(180deg, #FFFFFF 0%, var(--parchment-base) 100%);
}
.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

/* 左栏内容 */
.hero-left-col {
  text-align: left;
}

/* 1. 胶囊公告（小圆点 + 一句发布信息） */
.hero-capsule {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: #FFFFFF;
  border: 1px solid var(--parchment-border);
  padding: 6px 16px;
  border-radius: var(--radius-capsule);
  font-size: 13px;
  color: var(--ink-secondary);
  margin-bottom: 24px;
}
.capsule-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--compass-bronze);
  animation: nauticalPulse 2s infinite ease-in-out;
}
@keyframes nauticalPulse {
  0%, 100% { opacity: 0.4; transform: scale(0.9); }
  50% { opacity: 1; transform: scale(1.2); }
}

/* 2. 品牌色产品名，约 42px，字距略紧 */
.hero-product-name {
  font-size: 42px;
  font-weight: 800;
  letter-spacing: -1.2px;
  color: var(--color-brand);
  line-height: 1.15;
  margin-bottom: 12px;
}

/* 3. 主张，约 24px，字距略宽 */
.hero-proposition {
  font-size: 24px;
  font-weight: 500;
  letter-spacing: 0.8px;
  color: var(--ink-primary);
  margin-bottom: 20px;
  line-height: 1.4;
}

/* 4. 灰色介绍，最宽约 600px */
.hero-description {
  max-width: 600px;
  font-size: 16px;
  color: var(--ink-secondary);
  line-height: 1.7;
  margin-bottom: 30px;
}

/* 5. 两个入口 */
.hero-actions-row {
  display: flex;
  gap: 16px;
  margin-bottom: 28px;
}

/* 6. 一条品牌色信息条（三行以内） */
.hero-info-banner {
  max-width: 600px;
  background: rgba(24, 58, 83, 0.06);
  border-left: 3px solid var(--color-brand);
  padding: 12px 18px;
  border-radius: 0 8px 8px 0;
  font-size: 13.5px;
  color: #1A3E5C;
  line-height: 1.6;
  margin-bottom: 28px;
}

/* 7. 三条短信任点，带小勾 */
.hero-trust-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.trust-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  color: var(--ink-secondary);
}
.trust-item svg {
  width: 16px;
  height: 16px;
  color: var(--color-brand);
  flex-shrink: 0;
}

/* 右栏：最宽约 460px 演示卡片，圆角约 20px */
.hero-right-col {
  display: flex;
  justify-content: flex-end;
}
.demo-window-card {
  width: 100%;
  max-width: 460px;
  background: #FFFFFF;
  border: 1px solid var(--parchment-border);
  border-radius: 20px;
  box-shadow: 0 20px 45px rgba(37, 32, 26, 0.08);
  overflow: hidden;
  text-align: left;
}

/* 顶栏仿窗口（三个圆点 + 右侧小标题） */
.demo-header {
  height: 44px;
  background: var(--parchment-warm);
  border-bottom: 1px solid var(--parchment-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
}
.demo-dots {
  display: flex;
  gap: 6px;
}
.demo-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: #D3C7B5;
}
.demo-title {
  font-size: 12px;
  font-family: var(--font-mono);
  color: var(--ink-secondary);
}

/* 对话区 */
.demo-body {
  padding: 22px 20px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  background: #FFFFFF;
}

/* 用户气泡 */
.chat-bubble-user {
  align-self: flex-end;
  background: #ECE5D7;
  color: var(--ink-primary);
  padding: 12px 16px;
  border-radius: 14px 14px 2px 14px;
  font-size: 13.5px;
  line-height: 1.6;
  max-width: 90%;
}

/* AI 回复区 */
.chat-bubble-ai {
  align-self: flex-start;
  border-left: 3px solid var(--color-brand);
  background: #FAF7F0;
  padding: 14px 16px;
  border-radius: 0 14px 14px 14px;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--ink-primary);
  width: 100%;
}
.ai-role {
  font-weight: 700;
  color: var(--color-brand);
  font-size: 12px;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

/* 深色等宽代码块 */
.demo-code-block {
  background: #1C242B;
  color: #E2ECF2;
  border-radius: 8px;
  padding: 12px 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.5;
  margin-top: 10px;
  overflow-x: auto;
}
.code-comment { color: #7B8E9B; }
.code-keyword { color: #D89552; font-weight: 600; }
.code-string { color: #6FB89F; }
.code-func { color: #E5BE72; }

/* 底部三个点正在输入 */
.typing-indicator {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 4px 8px;
  width: fit-content;
}
.typing-dot {
  width: 6px;
  height: 6px;
  background: var(--color-brand);
  border-radius: 50%;
  opacity: 0.35;
  animation: nauticalTyping 1.4s infinite ease-in-out;
}
.typing-dot:nth-child(1) { animation-delay: 0s; }
.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }
@keyframes nauticalTyping {
  0%, 80%, 100% { transform: scale(0.8); opacity: 0.35; }
  40% { transform: scale(1.2); opacity: 1; }
}

@media (max-width: 968px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 48px;
  }
  .hero-right-col {
    justify-content: flex-start;
  }
}

/* ==========================================================================
   能力区：浅色底，上下细分割线。
   标题居中 38px，说明居中且最宽约 720px。下面 6 张卡，桌面 3 列，间距 28px。
   每张卡白底、1px 浅灰边、圆角 12px、内边距 28px；上方 48px 线性图标。
   悬停上移约 4px，边框变为品牌色。标题 18px，说明 14px 灰色。
   窄于 968px 改为 2 列，窄于 640px 改为 1 列。
   ========================================================================== */
.abilities-section {
  background-color: var(--parchment-warm);
  border-top: 1px solid var(--parchment-border);
  border-bottom: 1px solid var(--parchment-border);
}
.ability-grid-6 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}
.ability-card {
  background: #FFFFFF;
  border: 1px solid var(--parchment-border);
  border-radius: var(--radius-card);
  padding: 28px;
  text-align: left;
  transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}
.ability-card:hover {
  transform: translateY(-4px);
  border-color: var(--color-brand);
  box-shadow: 0 12px 28px rgba(24, 58, 83, 0.08);
}
.ability-icon-box {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: rgba(24, 58, 83, 0.08);
  border: 1px solid rgba(24, 58, 83, 0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-brand);
  margin-bottom: 20px;
}
.ability-card-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--ink-primary);
  margin-bottom: 10px;
}
.ability-card-desc {
  font-size: 14px;
  color: var(--ink-secondary);
  line-height: 1.7;
}

@media (max-width: 968px) {
  .ability-grid-6 {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (max-width: 640px) {
  .ability-grid-6 {
    grid-template-columns: 1fr;
  }
}

/* ==========================================================================
   产品矩阵：白底。标题样式与能力区相同。
   4 张卡，桌面 4 列，间距 24px；窄于 1200px 改为 2 列，窄于 640px 改为 1 列。
   小角标、名称、一行彩色副题、两行说明、底部分割线下的两个元信息。
   角标只用字重和文案区分角色，颜色不超过品牌色加一个强调色。
   ========================================================================== */
.matrix-section {
  background-color: #FFFFFF;
}
.matrix-grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.matrix-card {
  background: var(--parchment-base);
  border: 1px solid var(--parchment-border);
  border-radius: var(--radius-card);
  padding: 24px;
  text-align: left;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: transform 0.2s ease, border-color 0.2s ease;
}
.matrix-card:hover {
  transform: translateY(-3px);
  border-color: var(--color-brand);
}
.matrix-badge {
  position: absolute;
  top: 18px;
  right: 18px;
  font-size: 11px;
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--color-brand);
  background: rgba(24, 58, 83, 0.08);
  padding: 2px 8px;
  border-radius: 4px;
}
.matrix-badge.accent-alt {
  color: var(--compass-bronze);
  background: rgba(168, 107, 50, 0.1);
}
.matrix-name {
  font-size: 20px;
  font-weight: 700;
  color: var(--ink-primary);
  margin-top: 8px;
  margin-bottom: 6px;
}
.matrix-sub {
  font-size: 13px;
  font-weight: 600;
  color: var(--color-brand);
  margin-bottom: 12px;
}
.matrix-desc {
  font-size: 13.5px;
  color: var(--ink-secondary);
  line-height: 1.6;
  margin-bottom: 20px;
  flex-grow: 1;
}
.matrix-meta-row {
  border-top: 1px solid var(--parchment-border);
  padding-top: 14px;
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  font-family: var(--font-mono);
  color: var(--ink-subtle);
}

@media (max-width: 1200px) {
  .matrix-grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (max-width: 640px) {
  .matrix-grid-4 {
    grid-template-columns: 1fr;
  }
}

/* ==========================================================================
   开发者区：左右 1:1，间距 60px，窄于 1200px 改为上下堆叠
   港口税则风格（Port Tariff）与最短可运行调用
   左：左对齐标题约 34px、一段说明、4 条带勾选项、一个描边按钮链到文档
   右：深色代码面板，圆角 12px，等宽字体，语法着色
   ========================================================================== */
.dev-section {
  background-color: var(--parchment-warm);
  border-top: 1px solid var(--parchment-border);
  border-bottom: 1px solid var(--parchment-border);
}
.dev-flex-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.dev-left-col {
  text-align: left;
}
.dev-title {
  font-size: 34px;
  font-weight: 700;
  letter-spacing: -0.6px;
  color: var(--ink-primary);
  line-height: 1.25;
  margin-bottom: 18px;
}
.dev-desc {
  font-size: 15.5px;
  color: var(--ink-secondary);
  line-height: 1.7;
  margin-bottom: 24px;
}
.dev-checklist {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 32px;
}
.dev-check-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 14px;
  color: var(--ink-primary);
}
.dev-check-item .check-icon {
  width: 18px;
  height: 18px;
  color: var(--color-brand);
  flex-shrink: 0;
  margin-top: 2px;
}

/* 深色代码面板 */
.code-panel-box {
  background: #182026;
  border: 1px solid #2F3B44;
  border-radius: var(--radius-card);
  overflow: hidden;
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.14);
  text-align: left;
}
.code-panel-header {
  height: 42px;
  background: #11171C;
  border-bottom: 1px solid #253038;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
}
.code-pre {
  padding: 20px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  color: #E6EEF4;
}

@media (max-width: 1200px) {
  .dev-flex-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

/* ==========================================================================
   动态区：标题行两端对齐，左侧标题，右侧「查看全部」
   下面一张通栏列表，小标签（最多两种：PORT / LOG）、标题、日期。
   悬停只改变行背景。窄于 640px 时日期换到标题下方。
   ========================================================================== */
.news-section {
  background: #FFFFFF;
}
.news-header-between {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 32px;
  border-bottom: 2px solid var(--parchment-border);
  padding-bottom: 16px;
}
.news-main-title {
  font-size: 32px;
  font-weight: 700;
  letter-spacing: -0.6px;
  color: var(--ink-primary);
}
.news-view-all {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-brand);
  text-decoration: none;
}
.news-view-all:hover {
  text-decoration: underline;
}

.news-full-list {
  border: 1px solid var(--parchment-border);
  border-radius: var(--radius-card);
  overflow: hidden;
}
.news-row-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  background: #FFFFFF;
  border-bottom: 1px solid var(--parchment-border);
  text-decoration: none;
  transition: background-color 0.2s ease;
}
.news-row-item:last-child {
  border-bottom: none;
}
.news-row-item:hover {
  background-color: var(--parchment-base);
}
.news-left-info {
  display: flex;
  align-items: center;
  gap: 16px;
}
.news-tag {
  font-size: 11px;
  font-family: var(--font-mono);
  font-weight: 700;
  padding: 3px 8px;
  border-radius: 4px;
}
.tag-port {
  background: rgba(24, 58, 83, 0.1);
  color: var(--color-brand);
}
.tag-log {
  background: rgba(168, 107, 50, 0.12);
  color: var(--compass-bronze);
}
.news-title-text {
  font-size: 15px;
  font-weight: 500;
  color: var(--ink-primary);
}
.news-date {
  font-size: 13px;
  font-family: var(--font-mono);
  color: var(--ink-subtle);
  white-space: nowrap;
}

@media (max-width: 640px) {
  .news-row-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
}

/* ==========================================================================
   未至之境留白展示区 (Terra Incognita Blank Area)
   海图未探海域留白并注明「未至之境」
   ========================================================================== */
.terra-incognita-section {
  background: #FCFBF7;
  border-top: 1px dashed var(--parchment-border);
  border-bottom: 1px dashed var(--parchment-border);
  padding: 80px 0;
  position: relative;
  overflow: hidden;
}
.terra-incognita-box {
  border: 2px dashed rgba(168, 107, 50, 0.35);
  border-radius: 16px;
  padding: 48px 36px;
  background: rgba(248, 244, 236, 0.6);
  text-align: center;
  position: relative;
}
.terra-stamp {
  display: inline-block;
  border: 2px solid var(--compass-red);
  color: var(--compass-red);
  padding: 4px 14px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: 2px;
  text-transform: uppercase;
  transform: rotate(-3deg);
  margin-bottom: 16px;
}
.terra-title {
  font-size: 26px;
  font-weight: 700;
  color: var(--ink-primary);
  margin-bottom: 12px;
}
.terra-desc {
  max-width: 680px;
  margin: 0 auto;
  font-size: 15px;
  color: var(--ink-secondary);
  line-height: 1.8;
}

/* ==========================================================================
   下载区：居中。标题、一句平台说明，然后主按钮 + 描边次按钮。
   窄于 640px 时按钮纵向排列并保持居中，不要拉成全宽。
   ========================================================================== */
.download-section {
  background: var(--parchment-warm);
  border-top: 1px solid var(--parchment-border);
  text-align: center;
}
.download-inner {
  max-width: 680px;
  margin: 0 auto;
}
.download-title {
  font-size: 34px;
  font-weight: 700;
  color: var(--ink-primary);
  margin-bottom: 16px;
  letter-spacing: -0.6px;
}
.download-subtext {
  font-size: 16px;
  color: var(--ink-secondary);
  line-height: 1.7;
  margin-bottom: 36px;
}
.download-buttons-group {
  display: inline-flex;
  gap: 16px;
  justify-content: center;
}
@media (max-width: 640px) {
  .download-buttons-group {
    flex-direction: column;
    align-items: center;
    width: auto;
  }
  .download-buttons-group a {
    width: auto;
    min-width: 200px;
  }
}

/* ==========================================================================
   页脚：白底，顶部分割线。四列，比例约 2:1:1:1。
   第一列是字标和两行品牌说明；其余三列是分组链接。底部一条版权与备案。
   ========================================================================== */
.footer-section {
  background: #FFFFFF;
  border-top: 1px solid var(--parchment-border);
  padding-top: 72px;
  padding-bottom: 40px;
}
.footer-top-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 56px;
  text-align: left;
}
.footer-brand-col {
  padding-right: 24px;
}
.footer-brand-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}
.footer-logo-img {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-brand-box);
  border: 1px solid var(--parchment-border);
}
.footer-brand-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink-primary);
}
.footer-desc-lines {
  font-size: 14px;
  color: var(--ink-secondary);
  line-height: 1.7;
}

.footer-col-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--ink-primary);
  margin-bottom: 18px;
}
.footer-link-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.footer-link-item a {
  font-size: 14px;
  color: var(--ink-secondary);
  text-decoration: none;
  transition: color 0.2s ease;
}
.footer-link-item a:hover {
  color: var(--color-brand);
}

.footer-bottom-bar {
  border-top: 1px solid var(--parchment-border);
  padding-top: 28px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  color: var(--ink-subtle);
  flex-wrap: wrap;
  gap: 12px;
}

@media (max-width: 968px) {
  .footer-top-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }
}
@media (max-width: 640px) {
  .footer-top-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }
}

/* 图片图鉴卡片 */
.gallery-item {
  border-radius: var(--radius-card);
  overflow: hidden;
  border: 1px solid var(--parchment-border);
  background: #FFFFFF;
}
.gallery-img {
  width: 100%;
  height: auto;
  display: block;
}
.gallery-caption {
  padding: 12px 16px;
  font-size: 13px;
  color: var(--ink-secondary);
  background: var(--parchment-base);
  border-top: 1px solid var(--parchment-border);
  text-align: left;
}

/* scroll-perf: keep first screen painted, defer the rest, drop blur on small screens */
main > section:not(:first-of-type) {
  content-visibility: auto;
  contain-intrinsic-size: auto 720px;
}
img {
  max-width: 100%;
}
@media (max-width: 968px) {
  .site-header,
  .nav-drawer,
  header {
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
  }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}