@import url('https://fonts.googleapis.com/css2?family=DM+Sans:ital,wght@0,400;0,500;0,700;1,400&family=Nunito:ital,wght@0,700;0,800;0,900;1,700&display=swap');

/* ============================================================
   CSS 自定义属性 & 重置
   ============================================================ */
:root {
  --c-white: #ffffff;
  --c-surface: #f5f5f5;
  --c-ink: #1f1f1f;
  --c-ink-60: rgba(31,31,31,0.6);
  --c-ink-20: rgba(31,31,31,0.12);
  --c-accent: #3a56e8;
  --c-accent-light: #eef0fd;
  --c-slash: #e8e0f7;

  --shadow-sm: 0 2px 6px rgba(31,31,31,0.08), 0 1px 2px rgba(31,31,31,0.06);
  --shadow-md: 0 6px 20px rgba(31,31,31,0.10), 0 2px 6px rgba(31,31,31,0.08);
  --shadow-lg: 0 16px 40px rgba(31,31,31,0.13), 0 4px 12px rgba(31,31,31,0.09);
  --shadow-xl: 0 32px 64px rgba(31,31,31,0.16), 0 8px 20px rgba(31,31,31,0.10);

  --radius-card: 4px;
  --radius-btn: 32px;
  --radius-lg: 12px;

  --font-body: 'DM Sans', system-ui, -apple-system, sans-serif;
  --font-display: 'Nunito', var(--font-body);

  --max-w: 1160px;
  --aside-w: 220px;
  --gap: 2rem;
  --header-h: 112px;

  --z-base: 1;
  --z-card: 2;
  --z-float: 3;
  --z-overlay: 4;
}

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

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

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--c-ink);
  background: var(--c-surface);
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
a:hover { text-decoration: underline; }
ul, ol, menu { list-style: none; }

/* ============================================================
   容器
   ============================================================ */
.container {
  max-width: var(--max-w);
  margin-inline: auto;
  padding-inline: 1.25rem;
}

/* ============================================================
   页面包裹
   ============================================================ */
.page-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  position: relative;
  z-index: var(--z-base);
}

/* ============================================================
   顶部导航（两行：品牌行 + 菜单行）
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-overlay);
  background: var(--c-white);
  box-shadow: var(--shadow-md);
}

.header-brand-row {
  background: var(--c-ink);
  padding-block: 0.65rem;
}

.header-brand-row .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 900;
  color: var(--c-white);
  letter-spacing: -0.01em;
}

.logo-mark {
  width: 32px;
  height: 32px;
  border-radius: 6px;
}

.contact-link {
  font-size: 0.875rem;
  color: rgba(255,255,255,0.75);
  padding: 0.4rem 0.9rem;
  border: 1px solid rgba(255,255,255,0.25);
  border-radius: var(--radius-btn);
  transition: background 0.2s, color 0.2s;
  min-height: 40px;
  display: flex;
  align-items: center;
}

.contact-link:hover {
  background: rgba(255,255,255,0.12);
  color: var(--c-white);
  text-decoration: none;
}

/* 菜单行 */
.header-nav-row {
  background: var(--c-white);
  border-bottom: 1px solid var(--c-ink-20);
  padding-block: 0;
}

.header-nav-row .container {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.header-nav-row .container::-webkit-scrollbar { display: none; }

/* details/summary 导航 */
#site-nav {
  position: relative;
}

.nav-summary {
  display: none;
}

.nav-menu {
  display: flex;
  flex-wrap: nowrap;
  gap: 0;
}

.nav-menu li a {
  display: flex;
  align-items: center;
  padding: 0.75rem 1rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--c-ink);
  white-space: nowrap;
  border-bottom: 3px solid transparent;
  transition: color 0.2s, border-color 0.2s;
  min-height: 48px;}

.nav-menu li a:hover,
.nav-menu li a[aria-current="page"] {
  color: var(--c-accent);
  border-bottom-color: var(--c-accent);
  text-decoration: none;
}

/* ============================================================
   眉标 / 小标签
   ============================================================ */
.page-eyebrow {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--c-accent);
  background: var(--c-accent-light);
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-btn);
  margin-bottom: 0.75rem;
}

/* ============================================================
   Hero — 首页
   ============================================================ */
.hero-wrap {
  position: relative;
  min-height: 70vh;
  background: var(--c-ink);
  overflow: hidden;
  display: flex;
  align-items: center;
}

.hero-layer {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.hero-layer--bg {
  background: radial-gradient(ellipse at 30% 60%, rgba(58,86,232,0.18) 0%, transparent 70%);
  z-index: 1;
}

.hero-layer--mid {
  background: radial-gradient(ellipse at 80% 20%, rgba(232,224,247,0.08) 0%, transparent 60%);
  z-index: 2;
}

.hero-inner {
  position: relative;
  z-index: 3;
  max-width: var(--max-w);
  margin-inline: auto;
  padding-inline: 1.25rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: var(--gap);
  min-height: 70vh;
  padding-block: 5rem 4rem;
}

.hero-text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 1rem;
}

.hero-eyebrow {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: rgba(255,255,255,0.6);
  text-transform: uppercase;
}

.hero-h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 900;
  color: var(--c-white);
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.hero-lead {
  font-size: 1.125rem;
  color: rgba(255,255,255,0.72);
  max-width: 42ch;
  line-height: 1.6;
}

.hero-ctas {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 0.5rem;
}

.hero-media {
  position: relative;
  z-index: var(--z-float);
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-img {
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  max-height: 380px;
  object-fit: cover;
  transform: translateZ(0) perspective(800px) rotateY(-4deg) rotateX(2deg);
  transition: transform 0.4s ease;
}

.hero-img:hover {
  transform: translateZ(0) perspective(800px) rotateY(0deg) rotateX(0deg);
}

.hero-media--empty {
  width: 100%;
  min-height: 240px;
  background: linear-gradient(135deg, rgba(255,255,255,0.06) 0%, rgba(58,86,232,0.12) 100%);
  border-radius: var(--radius-lg);
  border: 2px solid rgba(255,255,255,0.1);
}

/* 斜切色带 */
.hero-slash {
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 64px;
  background: var(--c-surface);
  clip-path: polygon(0 100%, 100% 40%, 100% 100%);
  z-index: 4;
}

/* ============================================================
   指南 Hero
   ============================================================ */
.guide-hero-section {
  background: linear-gradient(135deg, var(--c-ink) 0%, #2d2d3a 100%);
  position: relative;
  overflow: hidden;
  padding-bottom: 3rem;
}

.guide-hero-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--gap);
  align-items: center;
  padding-block: 3.5rem 2rem;
}

.guide-hero-text {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.guide-h1 {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 4vw, 2.5rem);
  font-weight: 900;
  color: var(--c-white);
  line-height: 1.2;
}

.guide-hero-media {
  position: relative;
  z-index: var(--z-float);
}

.guide-hero-img {
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-lg);
  max-width: 280px;
  max-height: 200px;
  object-fit: cover;
}

.guide-meta {
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
  font-size: 0.8rem;
  color: rgba(255,255,255,0.55);
}

.guide-slash {
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  height: 48px;
  background: var(--c-surface);
  clip-path: polygon(0 100%, 100% 30%, 100% 100%);
  z-index: 4;
}

/* ============================================================
   功能页 Banner
   ============================================================ */
.feature-banner {
  background: linear-gradient(150deg, #1a1a2e 0%, #16213e 50%, var(--c-ink) 100%);
  position: relative;
  overflow: hidden;
  padding-bottom: 3rem;
}

.feature-banner-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--gap);
  align-items: center;
  padding-block: 4rem 2rem;
}

.feature-banner-text {
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
}

.feature-h1 {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 4vw, 2.75rem);
  font-weight: 900;
  color: var(--c-white);
  line-height: 1.2;
}

.feature-lead {
  font-size: 1.05rem;
  color: rgba(255,255,255,0.68);
  max-width: 44ch;
}

.feature-banner-media {
  display: flex;
  justify-content: flex-end;
}

.feature-hero-img {
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-xl);
  max-width: 100%;
  max-height: 300px;
  object-fit: cover;
}

.feature-banner-deco {
  width: 100%;
  min-height: 200px;
  background: linear-gradient(135deg, rgba(58,86,232,0.15), rgba(232,224,247,0.08));
  border-radius: var(--radius-lg);
  border: 2px solid rgba(255,255,255,0.08);
  position: relative;
  overflow: hidden;
}

.feature-banner-deco::before {
  content: '';
  position: absolute;
  top: 20px;
  left: 20px;
  right: 20px;
  bottom: 20px;
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--radius-card);
}

.feature-slash {
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  height: 48px;
  background: var(--c-surface);
  clip-path: polygon(0 70%, 100% 0%, 100% 100%, 0 100%);
  z-index: 4;
}

/* ============================================================
   FAQ 页头
   ============================================================ */
.faq-header-section {
  background: var(--c-white);
  border-bottom: 4px solid var(--c-ink);
  padding-block: 3rem 2.5rem;
  position: relative;
}

.faq-header-inner {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-width: 680px;
}

.faq-h1 {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 4vw, 2.5rem);
  font-weight: 900;
  color: var(--c-ink);
}

.faq-lead {
  font-size: 1.05rem;
  color: var(--c-ink-60);
  line-height: 1.65;
}

.faq-header-deco {
  position: absolute;
  right: 0;
  top: 0;
  bottom: 0;
  width: 30%;
  background: repeating-linear-gradient(
    -45deg,
    transparent,
    transparent 10px,
    var(--c-surface) 10px,
    var(--c-surface) 12px
  );
  opacity: 0.6;
  clip-path: polygon(30% 0%, 100% 0%, 100% 100%, 0% 100%);
}

/* ============================================================
   About 页头
   ============================================================ */
.about-hero-section {
  background: var(--c-white);
  padding-block: 3.5rem 2rem;
  position: relative;
  overflow: hidden;
  border-bottom: 4px solid var(--c-ink);
}

.about-hero-inner {
  position: relative;
}

.about-hero-layers {
  position: absolute;
  inset: -2rem;
  pointer-events: none;
}

.about-layer {
  position: absolute;
  border-radius: 50%;
}

.about-layer--1 {
  width: 400px;
  height: 400px;
  right: -100px;
  top: -100px;
  background: var(--c-surface);
  z-index: 1;
  box-shadow: var(--shadow-lg);
}

.about-layer--2 {
  width: 280px;
  height: 280px;
  right: 30px;
  top: -40px;
  background: var(--c-accent-light);
  z-index: 2;
}

.about-layer--3 {
  width: 160px;
  height: 160px;
  right: 120px;
  top: 40px;
  background: rgba(58,86,232,0.08);
  z-index: 3;
}

.about-hero-content {
  position: relative;
  z-index: 4;
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
  max-width: 640px;
}

.about-h1 {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 4vw, 2.5rem);
  font-weight: 900;
  color: var(--c-ink);
  line-height: 1.2;
}

.about-lead {
  font-size: 1.05rem;
  color: var(--c-ink-60);
}

/* ============================================================
   Privacy 页头
   ============================================================ */
.privacy-header-section {
  background: var(--c-ink);
  padding-block: 3rem 2rem;
}

.privacy-h1 {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3.5vw, 2.25rem);
  font-weight: 900;
  color: var(--c-white);
  margin-top: 0.5rem;
  margin-bottom: 0.75rem;
}

/* ============================================================
   内容区主布局（aside + main-content）
   ============================================================ */
.content-section {
  padding-block: 2.5rem 3rem;
  display: flex;
  gap: 2.5rem;
  align-items: flex-start;
}

.page-aside {
  width: var(--aside-w);
  flex-shrink: 0;
  position: sticky;
  top: calc(var(--header-h) + 1rem);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  z-index: var(--z-card);
}

.aside-block {
  background: var(--c-white);
  border: 1.5px solid var(--c-ink-20);
  border-radius: var(--radius-card);
  padding: 1.1rem 1rem;
  box-shadow: var(--shadow-sm);
}

.aside-title {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  color: var(--c-ink);
  margin-bottom: 0.5rem;
}

.aside-block hr {
  border: none;
  border-top: 2px solid var(--c-ink-20);
  margin-bottom: 0.75rem;
}

.aside-links {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.aside-links li a {
  display: block;
  font-size: 0.85rem;
  color: var(--c-ink);
  padding: 0.35rem 0.5rem;
  border-radius: 3px;
  transition: background 0.15s, color 0.15s;
  min-height: 40px;
  display: flex;
  align-items: center;
  line-height: 1.3;
}

.aside-links li a:hover {
  background: var(--c-surface);
  color: var(--c-accent);
  text-decoration: none;
}

.aside-block--cta {
  background: var(--c-accent-light);
  border-color: var(--c-accent);
}

.aside-block--cta p {
  font-size: 0.875rem;
  margin-bottom: 0.75rem;
  color: var(--c-ink);
}

.aside-block--tip {
  background: #fffbec;
  border-color: #e8d880;
}

.aside-tip-label {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  background: #e8d880;
  color: #5a4a00;
  padding: 0.1rem 0.5rem;
  border-radius: 20px;
  margin-bottom: 0.5rem;
}

.aside-block--tip p {
  font-size: 0.85rem;
  line-height: 1.5;
  color: #5a4a00;
}

.main-content {
  flex: 1;
  min-width: 0;
  position: relative;
  z-index: var(--z-base);
}

/* ============================================================
   面包屑
   ============================================================ */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  font-size: 0.8rem;
  color: rgba(255,255,255,0.55);
  margin-bottom: 0.5rem;
}

.breadcrumb li {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.breadcrumb li::after {
  content: '/';
  opacity: 0.4;
}

.breadcrumb li:last-child::after {
  display: none;
}

.breadcrumb a {
  color: rgba(255,255,255,0.6);
}

.breadcrumb a:hover {
  color: var(--c-white);
}

/* ============================================================
   正文排版
   ============================================================ */
.prose {
  font-size: 1rem;
  line-height: 1.75;
  color: var(--c-ink);
}

.prose h2 {
  font-family: var(--font-display);
  font-size: 1.45rem;
  font-weight: 800;
  margin-top: 2rem;
  margin-bottom: 0.25rem;
  line-height: 1.25;
}

.prose h2 + hr,
.prose h3 + hr {
  border: none;
  border-top: 3px solid var(--c-ink);
  margin-bottom: 1rem;
}

.prose h3 {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  margin-top: 1.5rem;
  margin-bottom: 0.25rem;
}

.prose p {
  margin-bottom: 1rem;
}

.prose ul, .prose ol {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}

.prose ul { list-style: disc; }
.prose ol { list-style: decimal; }

.prose li {
  margin-bottom: 0.4rem;
}

.prose a {
  color: var(--c-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose strong {
  font-weight: 700;
}

.prose blockquote {
  border-left: 4px solid var(--c-accent);
  padding-left: 1rem;
  color: var(--c-ink-60);
  margin: 1.25rem 0;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.25rem;
  font-size: 0.9rem;
}

.prose th, .prose td {
  border: 1px solid var(--c-ink-20);
  padding: 0.5rem 0.75rem;
  text-align: left;
}

.prose th {
  background: var(--c-ink);
  color: var(--c-white);
  font-weight: 600;
}

.prose tr:nth-child(even) td {
  background: var(--c-surface);
}

.prose img {
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-md);
  margin-block: 1.25rem;
}

/* ============================================================
   按钮（clay 质感）
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.65rem 1.5rem;
  border-radius: var(--radius-btn);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.9rem;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s;
  text-decoration: none !important;
  min-height: 44px;
  border: 2.5px solid transparent;
  line-height: 1.2;
}

.btn--clay {
  box-shadow: 0 4px 0 rgba(31,31,31,0.25), 0 2px 8px rgba(31,31,31,0.12);
}

.btn--clay:hover {
  transform: translateY(-2px);
  box-shadow: 0 7px 0 rgba(31,31,31,0.22), 0 4px 16px rgba(31,31,31,0.14);
}

.btn--clay:active {
  transform: translateY(2px);
  box-shadow: 0 1px 0 rgba(31,31,31,0.2);
}

.btn--primary {
  background: var(--c-accent);
  color: var(--c-white);
  border-color: transparent;
}

.btn--ghost {
  background: var(--c-white);
  color: var(--c-ink);
  border-color: var(--c-ink-20);
}

.btn--sm {
  padding: 0.45rem 1rem;
  font-size: 0.82rem;
  min-height: 40px;
}

/* ============================================================
   导航卡片（首页）
   ============================================================ */
.nav-cards-section {
  padding-block: 1rem 3rem;
}

.nav-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}

.nav-card {
  background: var(--c-white);
  border: 2px solid var(--c-ink);
  border-radius: var(--radius-card);
  position: relative;
  z-index: var(--card-z, 1);
  transition: transform 0.2s, box-shadow 0.2s;
  box-shadow: var(--shadow-sm);
}

.nav-card:hover {
  transform: translateY(-4px) translateZ(0);
  box-shadow: var(--shadow-lg);
}

.nav-card-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 1.1rem;
  min-height: 64px;
  text-decoration: none !important;
}

.nav-card-num {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 900;
  color: var(--c-accent);
  min-width: 2rem;
  flex-shrink: 0;
}

.nav-card-title {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--c-ink);
  line-height: 1.35;
  flex: 1;
}

.nav-card-arrow {
  color: var(--c-accent);
  font-size: 1.1rem;
  flex-shrink: 0;
  opacity: 0;
  transform: translateX(-6px);
  transition: opacity 0.2s, transform 0.2s;
}

.nav-card:hover .nav-card-arrow {
  opacity: 1;
  transform: translateX(0);
}

/* ============================================================
   子页卡片网格
   ============================================================ */
.children-section {
  padding-block: 1rem 3rem;
}

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.channel-card {
  background: var(--c-white);
  border: 2px solid var(--c-ink-20);
  border-radius: var(--radius-card);
  position: relative;
  z-index: var(--card-z, 1);
  transition: transform 0.22s, box-shadow 0.22s, border-color 0.22s;
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

.channel-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--c-accent), var(--c-slash));
  opacity: 0;
  transition: opacity 0.2s;
}

.channel-card:hover {
  transform: translateY(-5px) translateZ(0);
  box-shadow: var(--shadow-lg);
  border-color: var(--c-accent);
}

.channel-card:hover::before {
  opacity: 1;
}

.card-inner {
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  height: 100%;
}

.card-title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 800;
  line-height: 1.3;
}

.card-title a {
  color: var(--c-ink);
  text-decoration: none;
}

.card-title a:hover {
  color: var(--c-accent);
}

.card-date {
  font-size: 0.78rem;
  color: var(--c-ink-60);
}

.card-desc {
  font-size: 0.88rem;
  color: var(--c-ink-60);
  line-height: 1.55;
  flex: 1;
}

.card-link {
  font-size: 0.83rem;
  font-weight: 600;
  color: var(--c-accent);
  text-decoration: none;
  margin-top: 0.25rem;
}

.card-link:hover {
  text-decoration: underline;
}

/* ============================================================
   区块标题 + hr
   ============================================================ */
.section-title {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 900;
  color: var(--c-ink);
  margin-bottom: 0.25rem;
}

.section-title + hr {
  border: none;
  border-top: 3px solid var(--c-ink);
  margin-bottom: 1.5rem;
}

/* ============================================================
   FAQ — dl 列表
   ============================================================ */
.faq-dl-section {
  margin-top: 2.5rem;
}

.faq-dl {
  margin-top: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.faq-dl dt {
  background: var(--c-ink);
  padding: 0.85rem 1.1rem;
  border-radius: var(--radius-card) var(--radius-card) 0 0;
  margin-top: 1rem;
}

.faq-dl dt:first-of-type {
  margin-top: 0;
}

.faq-dl dt a {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--c-white);
  text-decoration: none;
}

.faq-dl dt a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.faq-dl dd {
  background: var(--c-white);
  border: 1.5px solid var(--c-ink-20);
  border-top: none;
  padding: 0.75rem 1.1rem;
  border-radius: 0 0 var(--radius-card) var(--radius-card);
  font-size: 0.9rem;
  color: var(--c-ink-60);
  line-height: 1.6;
}

/* ============================================================
   功能页操作行
   ============================================================ */
.feature-action-row {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 2rem;
  margin-bottom: 1.5rem;
  padding: 1.5rem;
  background: var(--c-white);
  border: 2px solid var(--c-ink-20);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-sm);
}

/* ============================================================
   指南页底部操作
   ============================================================ */
.guide-footer-nav {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--c-ink-20);
}

/* ============================================================
   默认页头
   ============================================================ */
.default-header-section {
  padding-block: 2.5rem 0;
}

.default-header-section h1 {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3.5vw, 2.25rem);
  font-weight: 900;
}

/* ============================================================
   页脚
   ============================================================ */
.site-footer {
  margin-top: auto;
  background: var(--c-ink);
  color: var(--c-white);
}

.footer-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  padding-block: 3rem 2rem;
}

.footer-mega-brand {
  font-family: var(--font-display);
  font-size: clamp(2rem, 6vw, 4rem);
  font-weight: 900;
  color: var(--c-white);
  opacity: 0.12;
  letter-spacing: -0.03em;
  line-height: 0.9;
  margin-bottom: 1rem;
  user-select: none;
}

.footer-address {
  font-style: normal;
  font-size: 0.88rem;
  color: rgba(255,255,255,0.6);
  line-height: 1.65;
}

.footer-about-link {
  display: inline-block;
  margin-top: 0.75rem;
  color: rgba(255,255,255,0.7);
  font-size: 0.85rem;
  border-bottom: 1px solid rgba(255,255,255,0.25);
  min-height: 40px;
  display: flex;
  align-items: center;
  width: fit-content;
}

.footer-about-link:hover {
  color: var(--c-white);
  text-decoration: none;
}

.footer-links-col {
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding-bottom: 0.5rem;
}

.footer-links-col ul {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.footer-links-col ul li a {
  display: block;
  font-size: 0.875rem;
  color: rgba(255,255,255,0.65);
  padding: 0.35rem 0;
  border-bottom: 1px solid rgba(255,255,255,0.06);
  transition: color 0.15s;
  min-height: 40px;
  display: flex;
  align-items: center;
}

.footer-links-col ul li a:hover {
  color: var(--c-white);
  text-decoration: none;
}

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-block: 1rem;
}

.footer-bottom-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.footer-copy {
  font-size: 0.8rem;
  color: rgba(255,255,255,0.4);
}

.footer-bottom-links {
  display: flex;
  gap: 1.25rem;
}

.footer-bottom-links a {
  font-size: 0.8rem;
  color: rgba(255,255,255,0.5);
  transition: color 0.15s;
  min-height: 40px;
  display: flex;
  align-items: center;
}

.footer-bottom-links a:hover {
  color: var(--c-white);
  text-decoration: none;
}

/* ============================================================
   侧边栏相关指南
   ============================================================ */
.sidebar-related {
  background: var(--c-white);
  border: 1.5px solid var(--c-ink-20);
  border-radius: var(--radius-card);
  padding: 1.1rem 1rem;
  box-shadow: var(--shadow-sm);
}

.sidebar-related hr {
  border: none;
  border-top: 2px solid var(--c-ink-20);
  margin-bottom: 0.75rem;
}

/* ============================================================
   动效：交错列表 + hover 微交互
   ============================================================ */
@media (prefers-reduced-motion: no-preference) {
  .stagger-list > * {
    opacity: 0;
    transform: translateY(20px);
    animation: stagger-in 0.45s ease forwards;
  }

  .stagger-list > *:nth-child(1) { animation-delay: 0.05s; }
  .stagger-list > *:nth-child(2) { animation-delay: 0.10s; }
  .stagger-list > *:nth-child(3) { animation-delay: 0.15s; }
  .stagger-list > *:nth-child(4) { animation-delay: 0.20s; }
  .stagger-list > *:nth-child(5) { animation-delay: 0.25s; }
  .stagger-list > *:nth-child(6) { animation-delay: 0.30s; }
  .stagger-list > *:nth-child(7) { animation-delay: 0.35s; }
  .stagger-list > *:nth-child(8) { animation-delay: 0.40s; }

  @keyframes stagger-in {
    to { opacity: 1; transform: translateY(0); }
  }

  .btn--clay {
    will-change: transform;
  }
}

@media (prefers-reduced-motion: reduce) {
  .stagger-list > * {
    opacity: 1;
    transform: none;
    animation: none;
  }
  * {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

/* ============================================================
   移动端断点
   ============================================================ */
@media (max-width: 768px) {
  :root {
    --aside-w: 100%;
    --header-h: 96px;
  }

  /* 品牌行 */
  .brand-name { font-size: 1.1rem; }

  /* 导航切换为 details */
  .nav-summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.6rem 0;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--c-ink);
    list-style: none;
    min-height: 44px;
  }

  .nav-summary::-webkit-details-marker { display: none; }

  .nav-summary::after {
    content: '▾';
    font-size: 0.8rem;
    transition: transform 0.2s;
  }

  #site-nav[open] .nav-summary::after {
    transform: rotate(180deg);
  }

  .nav-menu {
    flex-direction: column;
    padding-bottom: 0.5rem;
    border-top: 1px solid var(--c-ink-20);
  }

  .nav-menu li a {
    padding: 0.55rem 0.5rem;
    border-bottom: 1px solid var(--c-ink-20);
    border-left: none;
    min-height: 44px;
  }

  /* Hero */
  .hero-inner {
    grid-template-columns: 1fr;
    min-height: auto;
    padding-block: 3rem 5rem;
  }

  .hero-media { display: none; }

  .hero-h1 { font-size: 1.8rem; }

  /* Guide hero */
  .guide-hero-inner {
    grid-template-columns: 1fr;
  }

  .guide-hero-media { display: none; }

  /* Feature banner */
  .feature-banner-inner {
    grid-template-columns: 1fr;
  }

  .feature-banner-media { display: none; }

  /* 内容区 */
  .content-section {
    flex-direction: column;
  }

  .page-aside {
    position: static;
    width: 100%;
  }

  /* 页脚 */
  .footer-inner {
    grid-template-columns: 1fr;
  }

  .footer-mega-brand { font-size: 2.5rem; }

  .footer-bottom-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }

  /* 卡片网格 */
  .cards-grid,
  .nav-cards-grid {
    grid-template-columns: 1fr;
  }

  /* About 层叠装饰在小屏隐藏 */
  .about-hero-layers { display: none; }

  /* FAQ 装饰 */
  .faq-header-deco { display: none; }

  /* 操作行 */
  .feature-action-row,
  .guide-footer-nav {
    flex-direction: column;
  }

  .feature-action-row .btn,
  .guide-footer-nav .btn {
    width: 100%;
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .hero-ctas {
    flex-direction: column;
  }

  .hero-ctas .btn {
    width: 100%;
    justify-content: center;
  }

  .breadcrumb { font-size: 0.75rem; }
}