/* ==========================================================================
   活明白 (HowToLiveBetter) 官网样式表
   Design Language: Apple HIG Inspired / Modern Editorial / Clean Minimalist
   Responsive & Dark Mode Supported
   ========================================================================== */

/* --- CSS 变量与设计令牌 --- */
:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-serif: "New York", ui-serif, Georgia, Cambria, "Songti SC", "Source Han Serif SC", serif;
  --font-mono: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

  /* 基础明亮模式色盘 (Warm & Clean Paper) */
  --bg-primary: #fcfbf9;
  --bg-secondary: #f4f2ee;
  --bg-tertiary: #ebe7e0;
  --card-bg: #ffffff;
  --card-bg-elevated: #ffffff;
  --card-border: rgba(0, 0, 0, 0.07);
  --card-border-hover: rgba(0, 0, 0, 0.14);
  --card-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.04), 0 2px 6px -1px rgba(0, 0, 0, 0.02);
  --card-shadow-hover: 0 12px 32px -4px rgba(0, 0, 0, 0.08), 0 4px 12px -2px rgba(0, 0, 0, 0.04);

  --text-primary: #18181b;
  --text-secondary: #52525b;
  --text-tertiary: #71717a;
  --text-quaternary: #a1a1aa;

  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-light: rgba(37, 99, 235, 0.08);

  --orange: #ea580c;
  --orange-light: rgba(234, 88, 12, 0.09);
  --green: #16a34a;
  --green-light: rgba(22, 163, 74, 0.09);
  --red: #dc2626;
  --red-light: rgba(220, 38, 38, 0.09);
  --purple: #7c3aed;
  --purple-light: rgba(124, 58, 237, 0.09);

  --nav-bg: rgba(252, 251, 249, 0.82);
  --nav-border: rgba(0, 0, 0, 0.06);

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-full: 9999px;

  --container-max: 1160px;
  --transition-fast: 0.18s ease;
  --transition-normal: 0.28s cubic-bezier(0.16, 1, 0.3, 1);
}

/* 强制暗黑模式或跟随系统 */
[data-theme="dark"] {
  --bg-primary: #09090b;
  --bg-secondary: #141417;
  --bg-tertiary: #1f1f23;
  --card-bg: #131316;
  --card-bg-elevated: #1a1a1f;
  --card-border: rgba(255, 255, 255, 0.08);
  --card-border-hover: rgba(255, 255, 255, 0.18);
  --card-shadow: 0 4px 24px -2px rgba(0, 0, 0, 0.45);
  --card-shadow-hover: 0 14px 36px -4px rgba(0, 0, 0, 0.6);

  --text-primary: #f4f4f5;
  --text-secondary: #a1a1aa;
  --text-tertiary: #71717a;
  --text-quaternary: #52525b;

  --accent: #3b82f6;
  --accent-hover: #60a5fa;
  --accent-light: rgba(59, 130, 246, 0.16);

  --orange: #f97316;
  --orange-light: rgba(249, 115, 22, 0.16);
  --green: #22c55e;
  --green-light: rgba(34, 197, 94, 0.16);
  --red: #ef4444;
  --red-light: rgba(239, 68, 68, 0.16);
  --purple: #8b5cf6;
  --purple-light: rgba(139, 92, 246, 0.16);

  --nav-bg: rgba(9, 9, 11, 0.82);
  --nav-border: rgba(255, 255, 255, 0.08);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg-primary: #09090b;
    --bg-secondary: #141417;
    --bg-tertiary: #1f1f23;
    --card-bg: #131316;
    --card-bg-elevated: #1a1a1f;
    --card-border: rgba(255, 255, 255, 0.08);
    --card-border-hover: rgba(255, 255, 255, 0.18);
    --card-shadow: 0 4px 24px -2px rgba(0, 0, 0, 0.45);
    --card-shadow-hover: 0 14px 36px -4px rgba(0, 0, 0, 0.6);

    --text-primary: #f4f4f5;
    --text-secondary: #a1a1aa;
    --text-tertiary: #71717a;
    --text-quaternary: #52525b;

    --accent: #3b82f6;
    --accent-hover: #60a5fa;
    --accent-light: rgba(59, 130, 246, 0.16);

    --orange: #f97316;
    --orange-light: rgba(249, 115, 22, 0.16);
    --green: #22c55e;
    --green-light: rgba(34, 197, 94, 0.16);
    --red: #ef4444;
    --red-light: rgba(239, 68, 68, 0.16);
    --purple: #8b5cf6;
    --purple-light: rgba(139, 92, 246, 0.16);

    --nav-bg: rgba(9, 9, 11, 0.82);
    --nav-border: rgba(255, 255, 255, 0.08);
  }
}

/* --- 重置与基础设置 --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  min-height: 100vh;
  line-height: 1.65;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

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

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

button, input {
  font-family: inherit;
  font-size: inherit;
  border: none;
  background: none;
}

/* --- 布局容器 --- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

/* --- 顶部导航栏 (Navbar) --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--nav-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--nav-border);
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-icon {
  width: 38px;
  height: 38px;
  border-radius: 9px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
  border: 1px solid rgba(0, 0, 0, 0.08);
}

.brand-info {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text-primary);
}

.brand-sub {
  font-size: 0.72rem;
  color: var(--text-tertiary);
  font-weight: 500;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 26px;
  list-style: none;
}

.nav-link {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
  padding: 6px 2px;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* 主题切换开关 */
.theme-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  cursor: pointer;
  border: 1px solid var(--card-border);
  transition: all var(--transition-fast);
}

.theme-btn:hover {
  color: var(--text-primary);
  background: var(--bg-tertiary);
}

.theme-btn svg {
  width: 18px;
  height: 18px;
}

/* 按钮组 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 600;
  font-size: 0.94rem;
  padding: 10px 20px;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn-primary {
  background: var(--text-primary);
  color: var(--bg-primary);
  border: 1px solid transparent;
}

.btn-primary:hover {
  background: #333338;
  transform: translateY(-1px);
}

[data-theme="dark"] .btn-primary:hover {
  background: #e4e4e7;
}

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

.btn-secondary:hover {
  background: var(--bg-tertiary);
  transform: translateY(-1px);
}

.btn-sm {
  padding: 7px 14px;
  font-size: 0.84rem;
}

.btn-lg {
  padding: 13px 26px;
  font-size: 1.02rem;
}

/* 移动端菜单按钮 */
.mobile-toggle {
  display: none;
  width: 38px;
  height: 38px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  border: 1px solid var(--card-border);
  color: var(--text-primary);
  cursor: pointer;
}

/* --- 英雄区 (Hero Section) --- */
.hero-section {
  padding: 64px 0 72px;
  position: relative;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.95fr;
  align-items: center;
  gap: 48px;
}

.hero-badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  background: var(--orange-light);
  color: var(--orange);
  font-size: 0.84rem;
  font-weight: 600;
  margin-bottom: 20px;
}

.hero-title {
  font-size: clamp(2.2rem, 4.2vw, 3.4rem);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -0.025em;
  color: var(--text-primary);
  margin-bottom: 20px;
}

.hero-subtitle {
  font-size: clamp(1.05rem, 1.8vw, 1.25rem);
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 32px;
  max-width: 540px;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  margin-bottom: 32px;
}

.hero-meta-list {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  list-style: none;
  font-size: 0.88rem;
  color: var(--text-tertiary);
}

.hero-meta-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.hero-meta-item svg {
  width: 16px;
  height: 16px;
  color: var(--green);
}

/* --- 英雄区设备模型展示 (Device Mockup) --- */
.device-wrapper {
  position: relative;
  display: flex;
  justify-content: center;
}

.device-frame {
  width: 100%;
  max-width: 380px;
  background: var(--card-bg);
  border-radius: 40px;
  padding: 16px;
  border: 7px solid #27272a;
  box-shadow: 0 25px 60px -12px rgba(0, 0, 0, 0.2), 0 0 0 1px rgba(255, 255, 255, 0.1);
  position: relative;
}

.device-island {
  width: 90px;
  height: 22px;
  background: #000000;
  border-radius: var(--radius-full);
  margin: 0 auto 14px;
}

.app-screen {
  background: var(--bg-secondary);
  border-radius: 28px;
  padding: 18px 14px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  font-size: 0.82rem;
}

.app-search-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  background: var(--card-bg);
  border-radius: var(--radius-md);
  border: 1px solid var(--card-border);
  color: var(--text-tertiary);
}

.app-today-card {
  background: var(--card-bg);
  border-radius: 16px;
  padding: 14px;
  border: 1px solid var(--card-border);
  box-shadow: var(--card-shadow);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.card-tag {
  display: inline-flex;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--orange);
  background: var(--orange-light);
  padding: 2px 8px;
  border-radius: var(--radius-full);
  width: fit-content;
}

.app-card-title {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.35;
  color: var(--text-primary);
}

.app-card-quote {
  font-size: 0.78rem;
  color: var(--text-secondary);
  line-height: 1.5;
  padding-left: 8px;
  border-left: 2.5px solid var(--orange);
}

.badge-row {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 4px;
}

.badge {
  font-size: 0.68rem;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: 6px;
}

.badge-a { background: var(--green-light); color: var(--green); }
.badge-tier { background: var(--orange-light); color: var(--orange); }
.badge-benefit { background: var(--purple-light); color: var(--purple); }

.app-category-mini {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
}

.mini-cat-item {
  background: var(--card-bg);
  padding: 8px 10px;
  border-radius: 12px;
  border: 1px solid var(--card-border);
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.75rem;
  font-weight: 600;
}

.mini-cat-dot {
  width: 10px;
  height: 10px;
  border-radius: 3px;
}

/* --- 数据统计条 (Stats Banner) --- */
.stats-banner {
  padding: 32px 0;
  border-top: 1px solid var(--card-border);
  border-bottom: 1px solid var(--card-border);
  background: var(--bg-secondary);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}

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

.stat-number {
  font-size: clamp(2rem, 3.5vw, 2.8rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  line-height: 1.1;
}

.stat-label {
  font-size: 0.9rem;
  color: var(--text-tertiary);
  font-weight: 500;
}

/* --- 通用章节标题 --- */
.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 52px;
}

.section-tag {
  font-size: 0.84rem;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 10px;
  display: block;
}

.section-title {
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 14px;
  line-height: 1.25;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* --- 核心特色 (Pillars) --- */
.features-section {
  padding: 96px 0;
}

.pillars-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.pillar-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  box-shadow: var(--card-shadow);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
  display: flex;
  flex-direction: column;
}

.pillar-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--card-shadow-hover);
  border-color: var(--card-border-hover);
}

.pillar-icon-box {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
}

.pillar-icon-box svg {
  width: 26px;
  height: 26px;
}

.pillar-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.pillar-desc {
  font-size: 0.94rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 18px;
}

.pillar-check-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: auto;
  font-size: 0.86rem;
  color: var(--text-tertiary);
}

.pillar-check-list li {
  display: flex;
  align-items: center;
  gap: 8px;
}

.pillar-check-list svg {
  width: 14px;
  height: 14px;
  color: var(--green);
  flex-shrink: 0;
}

/* --- 交互式建议体验 (Interactive Tips Preview) --- */
.preview-section {
  padding: 96px 0;
  background: var(--bg-secondary);
}

.tips-explorer {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-xl);
  padding: 36px;
  box-shadow: var(--card-shadow);
}

.tips-tabs-nav {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 16px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--card-border);
  scrollbar-width: none;
}

.tips-tabs-nav::-webkit-scrollbar {
  display: none;
}

.tab-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: var(--bg-secondary);
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--transition-fast);
}

.tab-btn:hover {
  color: var(--text-primary);
  background: var(--bg-tertiary);
}

.tab-btn.active {
  color: #ffffff;
  background: var(--text-primary);
}

[data-theme="dark"] .tab-btn.active {
  color: #09090b;
  background: #f4f4f5;
}

.tip-display-card {
  display: grid;
  grid-template-columns: 1.35fr 1fr;
  gap: 36px;
  align-items: start;
}

.tip-content-main {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.tip-meta-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}

.tip-badge-id {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  padding: 3px 9px;
  border-radius: 6px;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
}

.tip-heading {
  font-family: var(--font-serif);
  font-size: 1.55rem;
  font-weight: 700;
  line-height: 1.32;
  color: var(--text-primary);
}

.plain-talk-box {
  background: var(--orange-light);
  border-left: 4px solid var(--orange);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 16px 20px;
}

.plain-talk-label {
  font-size: 0.76rem;
  font-weight: 700;
  color: var(--orange);
  text-transform: uppercase;
  margin-bottom: 4px;
}

.plain-talk-text {
  font-size: 1.02rem;
  color: var(--text-primary);
  line-height: 1.6;
}

.tip-side-details {
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  padding: 24px;
  border: 1px solid var(--card-border);
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.detail-row {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.detail-label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
}

.detail-value {
  font-size: 0.92rem;
  color: var(--text-primary);
  line-height: 1.5;
}

.source-link-box {
  padding-top: 12px;
  border-top: 1px dashed var(--card-border);
  font-size: 0.82rem;
  color: var(--text-tertiary);
  word-break: break-all;
}

/* --- 6 大主题分类 (Categories Section) --- */
.categories-section {
  padding: 96px 0;
}

.categories-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.category-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--card-shadow);
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: all var(--transition-fast);
}

.category-card:hover {
  transform: translateY(-3px);
  border-color: var(--card-border-hover);
  box-shadow: var(--card-shadow-hover);
}

.cat-header {
  display: flex;
  align-items: center;
  gap: 14px;
}

.cat-icon-wrap {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  font-size: 1.2rem;
}

.cat-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
}

.cat-meta {
  font-size: 0.78rem;
  color: var(--text-tertiary);
}

.cat-subtitle {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.cat-tags-list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: auto;
}

.cat-tag-pill {
  font-size: 0.76rem;
  padding: 3px 8px;
  background: var(--bg-secondary);
  border-radius: 6px;
  color: var(--text-secondary);
}

/* --- 小组件与离线搜索亮点 --- */
.spotlight-section {
  padding: 96px 0;
  background: var(--bg-secondary);
}

.spotlight-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.spotlight-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-xl);
  padding: 36px;
  box-shadow: var(--card-shadow);
}

.widget-preview-box {
  background: linear-gradient(145deg, #1e293b, #0f172a);
  border-radius: 22px;
  padding: 20px;
  color: #ffffff;
  max-width: 320px;
  margin: 0 auto;
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.3);
}

.widget-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.75rem;
  opacity: 0.75;
  margin-bottom: 12px;
}

.widget-title {
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.35;
  margin-bottom: 8px;
}

.widget-quote {
  font-size: 0.75rem;
  opacity: 0.85;
  line-height: 1.45;
  margin-bottom: 12px;
}

/* --- 常见问题解答 (FAQ) --- */
.faq-section {
  padding: 96px 0;
}

.faq-list {
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

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

.faq-question {
  width: 100%;
  text-align: left;
  padding: 20px 24px;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}

.faq-chevron {
  width: 20px;
  height: 20px;
  transition: transform var(--transition-fast);
  color: var(--text-tertiary);
  flex-shrink: 0;
}

.faq-item.open .faq-chevron {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s cubic-bezier(0.16, 1, 0.3, 1), padding 0.3s ease;
  padding: 0 24px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.65;
}

.faq-item.open .faq-answer {
  padding-bottom: 22px;
}

/* --- 底部转化区 (Download Banner) --- */
.cta-section {
  padding: 80px 0;
}

.cta-banner {
  background: linear-gradient(135deg, #18181b 0%, #27272a 100%);
  color: #ffffff;
  border-radius: var(--radius-xl);
  padding: 64px 48px;
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.15);
}

[data-theme="dark"] .cta-banner {
  background: linear-gradient(135deg, #131316 0%, #1f1f23 100%);
  border: 1px solid var(--card-border);
}

.cta-title {
  font-size: clamp(2rem, 3.5vw, 2.8rem);
  font-weight: 800;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.cta-subtitle {
  font-size: 1.15rem;
  opacity: 0.85;
  max-width: 580px;
  margin: 0 auto 36px;
  line-height: 1.6;
}

.cta-btn-group {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

/* --- 页脚 (Footer) --- */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--card-border);
  padding: 64px 0 36px;
  margin-top: auto;
}

.footer-top {
  display: grid;
  grid-template-columns: 1.8fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-brand-desc {
  font-size: 0.88rem;
  color: var(--text-tertiary);
  line-height: 1.65;
  margin-top: 12px;
  max-width: 320px;
}

.footer-col-title {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.footer-link-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.footer-link-list a:hover {
  color: var(--text-primary);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  padding-top: 32px;
  border-top: 1px solid var(--card-border);
  font-size: 0.82rem;
  color: var(--text-tertiary);
}

.footer-disclaimer {
  font-size: 0.78rem;
  color: var(--text-quaternary);
  line-height: 1.5;
  margin-top: 12px;
}

/* --- 隐私协议与条款专属排版 (Article Page) --- */
.policy-header {
  padding: 64px 0 40px;
  border-bottom: 1px solid var(--card-border);
  background: var(--bg-secondary);
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-tertiary);
  margin-bottom: 16px;
}

.policy-title {
  font-size: clamp(2rem, 3.5vw, 2.6rem);
  font-weight: 800;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.policy-meta {
  font-size: 0.9rem;
  color: var(--text-tertiary);
}

.policy-content-wrapper {
  padding: 56px 0 96px;
}

.policy-body {
  max-width: 820px;
  margin: 0 auto;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--text-secondary);
}

.policy-body h2 {
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 44px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--card-border);
}

.policy-body h3 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 28px 0 12px;
}

.policy-body p {
  margin-bottom: 16px;
}

.policy-body ul, .policy-body ol {
  margin: 12px 0 20px 24px;
}

.policy-body li {
  margin-bottom: 8px;
}

.policy-highlight-card {
  background: var(--green-light);
  border: 1px solid var(--green);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin: 24px 0 32px;
  color: var(--text-primary);
}

.policy-highlight-card strong {
  color: var(--green);
}

/* --- 回到顶部按钮 --- */
.back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  background: var(--card-bg);
  color: var(--text-primary);
  border: 1px solid var(--card-border);
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.12);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-fast);
  z-index: 90;
}

.back-to-top.show {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  transform: translateY(-2px);
  background: var(--bg-tertiary);
}

/* --- 移动端响应式断点 --- */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 40px;
    text-align: center;
  }

  .hero-subtitle {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-cta-group, .hero-meta-list {
    justify-content: center;
  }

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

  .spotlight-grid {
    grid-template-columns: 1fr;
    gap: 36px;
  }

  .footer-top {
    grid-template-columns: repeat(2, 1fr);
    gap: 36px;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    position: fixed;
    top: 68px;
    left: 0;
    width: 100%;
    background: var(--nav-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: stretch;
    padding: 24px;
    gap: 16px;
    border-bottom: 1px solid var(--nav-border);
    transform: translateY(-120%);
    transition: transform var(--transition-normal);
    box-shadow: var(--card-shadow);
  }

  .nav-menu.open {
    transform: translateY(0);
  }

  .mobile-toggle {
    display: flex;
  }

  .nav-actions .btn-download {
    display: none;
  }

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

  .pillars-grid, .categories-grid {
    grid-template-columns: 1fr;
  }

  .tip-display-card {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .tips-explorer {
    padding: 20px;
  }

  .cta-banner {
    padding: 44px 20px;
  }

  .footer-top {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}