/* ==========================================================================
   克拉云 (KELAYUN) - PRECISION SIGNAL COMMERCE DESIGN SYSTEM
   ========================================================================== */

:root {
  --bg-main: #FFFFFF;
  --bg-subtle: #F7F8FA;
  --bg-alt: #F4F6F8;
  --bg-card: #FAFAF8;
  --bg-footer: #F3F5F6;
  
  --text-main: #101828;
  --text-body: #475467;
  --text-muted: #7B8493;
  
  --brand-blue: #245BFF;
  --brand-dark: #162A45;
  --signal-green: #16A085;
  --blue-light: #EEF3FF;
  --green-light: #EDF8F4;
  --border-color: #E3E7ED;
  --border-subtle: #EDF0F3;
  
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Consolas, "Liberation Mono", Menlo, monospace;
  
  --container-max: 1240px;
  --article-max: 780px;
  --header-height: 68px;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  
  --transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Reset & Box Sizing */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-body);
  line-height: 1.75;
  font-size: 1.0625rem; /* 17px */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Typography Defaults */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.025em;
}

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

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

ul, ol {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* Layout Utilities */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

.article-container {
  width: 100%;
  max-width: var(--article-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* Monospace Badges & Eyebrows */
.mono-label {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.signal-dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--signal-green);
  margin-right: 8px;
  vertical-align: middle;
}

.signal-dot.blue {
  background-color: var(--brand-blue);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px; /* 44px–48px 保持商务感 */
  padding: 10px 22px;
  font-size: 0.9375rem; /* 15px (14px–16px) */
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: var(--transition);
  white-space: nowrap;
  gap: 8px;
}

.btn-primary {
  background-color: var(--brand-blue);
  color: #FFFFFF;
  border: 1px solid var(--brand-blue);
}

.btn-primary:hover {
  background-color: #1745db;
  border-color: #1745db;
  transform: translateY(-1px);
}

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

.btn-outline:hover {
  background-color: var(--bg-subtle);
  border-color: var(--text-muted);
}

.btn-text {
  background: transparent;
  color: var(--brand-blue);
  padding: 10px 0;
}

.btn-text:hover {
  color: var(--brand-dark);
}

/* ==========================================================================
   Header (PRECISION COMMERCE HEADER)
   ========================================================================== */
.site-header {
  height: var(--header-height);
  background-color: #FFFFFF;
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
}

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

.brand-logo {
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.brand-name {
  font-size: 1.3125rem; /* 21px (20px–22px) */
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.02em;
}

.brand-en {
  font-family: var(--font-mono);
  font-size: 0.6875rem; /* 11px (10px–12px) */
  font-weight: 700;
  color: var(--text-muted);
  letter-spacing: 0.12em;
}

.nav-desktop {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-desktop a {
  font-size: 0.9375rem; /* 15px (14px–15px) */
  font-weight: 500;
  color: var(--text-body);
}

.nav-desktop a:hover,
.nav-desktop a.active {
  color: var(--brand-blue);
}

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

.header-actions .btn-plan {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-body);
  padding: 8px 12px;
}

.header-actions .btn-plan:hover {
  color: var(--brand-blue);
}

.menu-toggle {
  display: none;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 700;
  padding: 6px 12px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-main);
}

/* Mobile Navigation Dropdown */
.nav-mobile {
  display: none;
  position: absolute;
  top: var(--header-height);
  left: 0;
  width: 100%;
  background-color: #FFFFFF;
  border-bottom: 1px solid var(--border-color);
  padding: 20px 24px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.05);
}

.nav-mobile.active {
  display: block;
}

.nav-mobile-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.nav-mobile-list a {
  font-size: 1.0625rem;
  font-weight: 500;
  color: var(--text-main);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-subtle);
}

.nav-mobile-cta {
  margin-top: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* ==========================================================================
   Hero Section (FULL WIDTH STACKED HERO)
   ========================================================================== */
.hero-section {
  background-color: var(--bg-main);
  padding: 56px 0 52px 0;
  border-bottom: 1px solid var(--border-color);
}

.hero-eyebrow-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 32px;
}

.hero-eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
}

.hero-eyebrow .mono-label {
  font-size: 0.75rem; /* 12px (11px–13px) */
}

.hero-tags {
  display: flex;
  align-items: center;
  gap: 12px;
}

.hero-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem; /* 12px (11px–12px) */
  font-weight: 600;
  color: var(--brand-dark);
  background-color: var(--bg-subtle);
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

.hero-h1 {
  margin-bottom: 0;
}

.hero-h1-primary {
  display: block;
  font-size: clamp(3.2rem, 4.2vw, 4.6rem); /* 约 51px–74px */
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.04em;
  color: var(--brand-blue);
  margin-bottom: 12px;
}

.hero-h1-statement {
  display: block;
  font-size: clamp(3rem, 4.5vw, 4.8rem); /* 约 48px–77px, 绝不超过 80px */
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.06; /* 1.03–1.08 */
  letter-spacing: -0.045em;
  max-width: 1050px; /* 不撑满整行 */
  margin-bottom: 20px; /* 标题与副标题间距 18px–24px */
}

.hero-h1-statement span {
  display: inline;
}

.hero-h1-sub {
  display: block;
  font-size: clamp(1.75rem, 2.3vw, 2.4rem); /* 约 28px–38px */
  font-weight: 650;
  color: var(--text-muted);
  letter-spacing: -0.02em;
  line-height: 1.35;
  margin-bottom: 24px; /* 副标题与正文间距 20px–28px */
}

.hero-desc {
  max-width: 860px; /* 820px–900px */
  font-size: 1.0625rem; /* 17px (17px–18px, 不超过 19px) */
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 30px; /* 正文与 CTA 间距 28px–34px */
}

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

/* ==========================================================================
   Signal Strip (PRECISION SIGNAL STRIP)
   ========================================================================== */
.signal-strip {
  background-color: var(--bg-subtle);
  border-bottom: 1px solid var(--border-color);
  padding: 24px 0;
}

.signal-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
}

.signal-col {
  padding: 4px 28px;
  border-left: 1px solid var(--border-color);
}

.signal-col:first-child {
  padding-left: 0;
  border-left: none;
}

.signal-col-header {
  display: flex;
  align-items: center;
  margin-bottom: 6px;
}

.signal-col-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.signal-col-val {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-main);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ==========================================================================
   Section Base & Rhythm
   ========================================================================== */
.site-section {
  padding: 88px 0;
  border-bottom: 1px solid var(--border-color);
}

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

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

.section-header-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 48px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
}

.section-index {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--brand-blue);
  letter-spacing: 0.08em;
}

.section-h2 {
  font-size: clamp(1.75rem, 3.2vw, 2.75rem);
  font-weight: 750;
  color: var(--text-main);
  letter-spacing: -0.03em;
}

/* ==========================================================================
   01 / WHY KELAYUN (Product Value)
   ========================================================================== */
.why-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 60px;
}

.why-left {
  border-right: 1px solid var(--border-color);
  padding-right: 32px;
}

.why-left-index {
  font-family: var(--font-mono);
  font-size: 3.5rem;
  font-weight: 800;
  color: var(--border-color);
  line-height: 1;
  margin-bottom: 12px;
}

.why-left-title {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--text-main);
  line-height: 1.4;
}

.why-right-statement {
  font-size: clamp(2rem, 3.6vw, 3.2rem);
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.035em;
  line-height: 1.2;
  margin-bottom: 48px;
}

.capability-rows {
  display: flex;
  flex-direction: column;
}

.capability-row {
  display: grid;
  grid-template-columns: 200px 1fr;
  align-items: baseline;
  padding: 24px 0;
  border-top: 1px solid var(--border-color);
}

.capability-row:last-child {
  border-bottom: 1px solid var(--border-color);
}

.cap-label {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--brand-blue);
  letter-spacing: 0.06em;
}

.cap-content {
  font-size: 1.0625rem;
  font-weight: 500;
  color: var(--text-main);
}

/* ==========================================================================
   02 / GLOBAL REGIONS (Region Directory)
   ========================================================================== */
.region-directory {
  display: flex;
  flex-direction: column;
  margin-top: 32px;
}

.region-row {
  display: grid;
  grid-template-columns: 340px 1fr;
  align-items: center;
  padding: 32px 0;
  border-top: 1px solid var(--border-color);
}

.region-row:last-child {
  border-bottom: 1px solid var(--border-color);
}

.region-meta {
  display: flex;
  align-items: baseline;
  gap: 16px;
}

.region-name {
  font-size: 1.625rem;
  font-weight: 750;
  color: var(--text-main);
  letter-spacing: -0.02em;
}

.region-count {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--brand-blue);
}

.location-list {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
}

.location-item {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-body);
  display: inline-flex;
  align-items: center;
}

.location-item::before {
  content: "";
  display: inline-block;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background-color: var(--signal-green);
  margin-right: 8px;
}

/* ==========================================================================
   03 / DEVICES (Horizontal Device Index)
   ========================================================================== */
.device-index {
  display: flex;
  flex-direction: column;
  margin-top: 32px;
}

.device-row {
  display: grid;
  grid-template-columns: 240px 140px 1fr;
  align-items: center;
  padding: 24px 0;
  border-top: 1px solid var(--border-color);
}

.device-row:last-child {
  border-bottom: 1px solid var(--border-color);
}

.device-name-wrap {
  display: flex;
  align-items: center;
  gap: 14px;
}

.device-icon-svg {
  width: 22px;
  height: 22px;
  color: var(--brand-dark);
}

.device-name {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -0.01em;
}

.device-category {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.08em;
}

.device-desc {
  font-size: 0.9375rem;
  color: var(--text-body);
}

/* ==========================================================================
   04 / AI + MEDIA (Asymmetric Text Grid)
   ========================================================================== */
.asym-grid {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 64px;
  margin-top: 32px;
}

.asym-col {
  display: flex;
  flex-direction: column;
}

.asym-col-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding-bottom: 16px;
  border-bottom: 2px solid var(--brand-dark);
  margin-bottom: 24px;
}

.asym-title {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 750;
  color: var(--text-main);
  letter-spacing: 0.06em;
}

.asym-num {
  font-family: var(--font-mono);
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--brand-blue);
  line-height: 1;
}

.asym-list {
  display: flex;
  flex-direction: column;
}

.asym-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 0;
  border-bottom: 1px solid var(--border-color);
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-main);
}

.asym-item .item-meta {
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--text-muted);
}

/* ==========================================================================
   05 / PLANS (Specification Pricing Rows)
   ========================================================================== */
.pricing-specs {
  display: flex;
  flex-direction: column;
  margin-top: 36px;
  gap: 16px;
}

.spec-row {
  display: grid;
  grid-template-columns: 160px 140px 1fr 160px 160px;
  align-items: center;
  padding: 24px 32px;
  background-color: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: var(--transition);
}

.spec-row:hover {
  border-color: #c9d2de;
}

.spec-row.recommended {
  border-left: 3px solid var(--brand-blue);
  background-color: #FFFFFF;
  box-shadow: 0 4px 16px rgba(36, 91, 255, 0.06);
}

.spec-name-wrap {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.spec-code {
  font-family: var(--font-mono);
  font-size: 1.1875rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: 0.04em;
}

.spec-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 700;
  color: var(--brand-blue);
  background-color: var(--blue-light);
  padding: 2px 6px;
  border-radius: 4px;
  width: fit-content;
}

.spec-data {
  font-size: 1.25rem;
  font-weight: 750;
  color: var(--text-main);
}

.spec-data span {
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--text-muted);
}

.spec-desc {
  font-size: 0.9375rem;
  color: var(--text-body);
  padding-right: 20px;
}

.spec-price {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-main);
}

.spec-row.recommended .spec-price {
  color: var(--brand-blue);
}

.spec-price span {
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--text-muted);
}

/* ==========================================================================
   06 / GUIDES (Editorial Article Index)
   ========================================================================== */
.editorial-index-layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 48px;
  margin-top: 36px;
}

.editorial-left {
  border-right: 1px solid var(--border-color);
  padding-right: 24px;
}

.editorial-tag {
  font-family: var(--font-mono);
  font-size: 1.125rem;
  font-weight: 750;
  color: var(--text-main);
  letter-spacing: 0.08em;
  margin-bottom: 8px;
}

.editorial-count {
  font-family: var(--font-mono);
  font-size: 3.5rem;
  font-weight: 800;
  color: var(--brand-blue);
  line-height: 1;
}

.article-rows-wrap {
  display: flex;
  flex-direction: column;
}

.article-row {
  display: grid;
  grid-template-columns: 48px 1fr 90px 36px;
  align-items: center;
  padding: 24px 16px;
  border-top: 1px solid var(--border-color);
  transition: var(--transition);
  border-radius: var(--radius-sm);
}

.article-row:last-child {
  border-bottom: 1px solid var(--border-color);
}

.article-row:hover {
  background-color: var(--blue-light);
  padding-left: 20px;
  padding-right: 12px;
}

.article-row:hover .row-arrow {
  transform: translate(2px, -2px);
  color: var(--brand-blue);
}

.row-num {
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-muted);
}

.row-content {
  padding-right: 24px;
}

.row-cat {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--brand-blue);
  margin-bottom: 4px;
}

.row-title {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.4;
  margin-bottom: 4px;
}

.row-title a {
  color: inherit;
}

.row-title a:hover {
  color: var(--brand-blue);
}

.row-excerpt {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.row-time {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-muted);
  text-align: right;
  white-space: nowrap;
}

.row-arrow {
  font-size: 1.25rem;
  color: var(--text-muted);
  text-align: right;
  transition: var(--transition);
  font-weight: 600;
}

/* ==========================================================================
   07 / NOTES (User Notes)
   ========================================================================== */
.notes-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 36px;
  margin-top: 36px;
}

.note-item {
  padding-top: 24px;
  border-top: 2px solid var(--brand-dark);
}

.note-num {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--brand-blue);
  margin-bottom: 8px;
}

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

.note-text {
  font-size: 0.9375rem;
  color: var(--text-body);
  line-height: 1.7;
}

/* ==========================================================================
   08 / FAQ (Full Width Question Rows)
   ========================================================================== */
.faq-list {
  display: flex;
  flex-direction: column;
  margin-top: 32px;
}

.faq-item {
  border-top: 1px solid var(--border-color);
  padding: 0;
}

.faq-item:last-child {
  border-bottom: 1px solid var(--border-color);
}

.faq-summary {
  display: grid;
  grid-template-columns: 48px 1fr 32px;
  align-items: center;
  padding: 24px 0;
  cursor: pointer;
  list-style: none;
  font-size: 1.1875rem;
  font-weight: 700;
  color: var(--text-main);
  transition: var(--transition);
}

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

.faq-summary:hover {
  color: var(--brand-blue);
}

.faq-num {
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-muted);
}

.faq-icon {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  color: var(--text-muted);
  text-align: right;
  transition: transform 0.2s ease;
}

details[open] .faq-icon {
  transform: rotate(45deg);
  color: var(--brand-blue);
}

.faq-content {
  padding: 0 0 28px 48px;
  font-size: 1rem;
  color: var(--text-body);
  line-height: 1.8;
}

.faq-content p + p {
  margin-top: 12px;
}

/* ==========================================================================
   Footer (PRECISION LIGHT FOOTER)
   ========================================================================== */
.site-footer {
  background-color: var(--bg-footer);
  border-top: 1px solid var(--border-color);
  padding: 64px 0 32px 0;
  color: var(--text-body);
}

.footer-top-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 48px;
  border-bottom: 1px solid var(--border-color);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding-right: 24px;
}

.footer-desc {
  font-size: 0.9375rem;
  color: var(--text-body);
  line-height: 1.7;
}

.footer-cta-box {
  margin-top: 8px;
}

.footer-col-title {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--text-main);
  margin-bottom: 18px;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-links a {
  font-size: 0.9375rem;
  color: var(--text-body);
}

.footer-links a:hover {
  color: var(--brand-blue);
}

/* Footer Recommended Links Strip */
.footer-external-strip {
  padding: 24px 0;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 24px;
}

.footer-external-label {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--text-muted);
}

.footer-external-links {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-external-links a {
  font-size: 0.875rem;
  color: var(--text-body);
}

.footer-external-links a:hover {
  color: var(--brand-blue);
  text-decoration: underline;
}

.footer-bottom {
  padding-top: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.footer-bottom-links {
  display: flex;
  gap: 20px;
}

.footer-bottom-links a:hover {
  color: var(--text-main);
}

/* ==========================================================================
   Editorial Document Styles (Articles & Guides)
   ========================================================================== */
.article-page-header {
  padding: 48px 0 36px 0;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 40px;
}

.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.breadcrumb a:hover {
  color: var(--brand-blue);
}

.breadcrumb-sep {
  color: var(--border-color);
}

.article-cat-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--brand-blue);
  background-color: var(--blue-light);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  margin-bottom: 16px;
}

.article-h1 {
  font-size: clamp(2rem, 3.8vw, 3rem);
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin-bottom: 20px;
}

.article-lead {
  font-size: 1.1875rem;
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 24px;
}

.article-meta-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--border-subtle);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* GEO Quick Answer Box */
.quick-answer {
  background-color: var(--green-light);
  border-left: 4px solid var(--signal-green);
  padding: 24px 28px;
  border-radius: var(--radius-sm);
  margin-bottom: 40px;
}

.quick-answer h2 {
  font-size: 1.1875rem;
  font-weight: 750;
  color: #0d6352;
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.quick-answer p {
  font-size: 1rem;
  color: #1a4d41;
  line-height: 1.8;
}

/* Table of Contents */
.toc-box {
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  margin-bottom: 48px;
}

.toc-title {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 750;
  color: var(--text-main);
  letter-spacing: 0.06em;
  margin-bottom: 16px;
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.toc-list a {
  font-size: 0.9375rem;
  color: var(--text-body);
}

.toc-list a:hover {
  color: var(--brand-blue);
  text-decoration: underline;
}

/* Article Body Content */
.article-content {
  font-size: 1.0625rem;
  line-height: 1.9;
  color: var(--text-body);
}

.article-content h2 {
  font-size: 1.75rem;
  font-weight: 750;
  color: var(--text-main);
  margin-top: 56px;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-color);
}

.article-content h3 {
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--text-main);
  margin-top: 36px;
  margin-bottom: 16px;
}

.article-content p {
  margin-bottom: 24px;
}

.article-content strong {
  color: var(--text-main);
  font-weight: 650;
}

.article-content ul,
.article-content ol {
  margin-bottom: 28px;
  padding-left: 24px;
}

.article-content ul {
  list-style: disc;
}

.article-content ol {
  list-style: decimal;
}

.article-content li {
  margin-bottom: 10px;
  line-height: 1.8;
}

.article-content blockquote {
  border-left: 3px solid var(--brand-blue);
  padding: 16px 24px;
  background-color: var(--blue-light);
  color: var(--brand-dark);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 32px 0;
}

/* Data Tables */
.table-responsive {
  width: 100%;
  overflow-x: auto;
  margin: 36px 0;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9375rem;
}

.data-table th {
  background-color: var(--bg-subtle);
  color: var(--text-main);
  font-weight: 700;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-color);
  white-space: nowrap;
}

.data-table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-body);
}

.data-table tr:last-child td {
  border-bottom: none;
}

.data-table tr:hover td {
  background-color: var(--bg-alt);
}

/* Article Internal Linking Box */
.article-cta-box {
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--brand-blue);
  border-radius: var(--radius-md);
  padding: 32px;
  margin: 56px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
}

.article-cta-text h3 {
  font-size: 1.25rem;
  margin-bottom: 6px;
}

.article-cta-text p {
  font-size: 0.9375rem;
  color: var(--text-body);
  margin-bottom: 0;
}

/* Related Articles Box */
.related-articles {
  margin-top: 64px;
  padding-top: 36px;
  border-top: 1px solid var(--border-color);
}

.related-title {
  font-size: 1.375rem;
  font-weight: 750;
  margin-bottom: 24px;
}

.related-links {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.related-item {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 12px 16px;
  background-color: var(--bg-subtle);
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.related-item:hover {
  background-color: var(--blue-light);
}

.related-item a {
  font-weight: 600;
  color: var(--text-main);
}

.related-item span {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Category Page Intro */
.cat-page-header {
  padding: 56px 0 40px 0;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 48px;
}

.cat-intro-p {
  max-width: 820px;
  font-size: 1.125rem;
  color: var(--text-body);
  line-height: 1.8;
  margin-top: 16px;
}

/* Static Pages Layout */
.static-page-header {
  padding: 56px 0 40px 0;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 48px;
}

.static-page-content {
  font-size: 1.0625rem;
  line-height: 1.9;
  color: var(--text-body);
  margin-bottom: 80px;
}

.static-page-content h2 {
  font-size: 1.625rem;
  font-weight: 750;
  margin-top: 48px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 10px;
}

.static-page-content p {
  margin-bottom: 20px;
}

.static-page-content ul {
  list-style: disc;
  padding-left: 24px;
  margin-bottom: 24px;
}

.static-page-content li {
  margin-bottom: 8px;
}

/* Sitemap Groups */
.sitemap-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 40px;
  margin-top: 36px;
}

.sitemap-group {
  border-top: 2px solid var(--brand-dark);
  padding-top: 20px;
}

.sitemap-group h3 {
  font-size: 1.25rem;
  font-weight: 750;
  margin-bottom: 16px;
}

.sitemap-group ul {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.sitemap-group a {
  color: var(--brand-blue);
  font-size: 1rem;
}

.sitemap-group a:hover {
  text-decoration: underline;
}

/* 404 Page */
.error-layout {
  padding: 100px 0;
  text-align: center;
}

.error-code {
  font-family: var(--font-mono);
  font-size: clamp(5rem, 12vw, 9rem);
  font-weight: 800;
  color: var(--border-color);
  line-height: 1;
  margin-bottom: 20px;
}

.error-title {
  font-size: 2rem;
  font-weight: 750;
  margin-bottom: 16px;
}

.error-desc {
  font-size: 1.125rem;
  color: var(--text-muted);
  max-width: 500px;
  margin: 0 auto 36px auto;
}

.error-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-h1-primary {
    font-size: clamp(2.875rem, 4.8vw, 3.5rem); /* 46px–56px */
    margin-bottom: 10px;
  }
  .hero-h1-statement {
    font-size: clamp(2.75rem, 5vw, 3.625rem); /* 44px–58px */
    margin-bottom: 18px;
  }
  .hero-h1-sub {
    font-size: clamp(1.625rem, 2.8vw, 2rem); /* 26px–32px */
    margin-bottom: 22px;
  }
  .hero-desc {
    font-size: 1.0625rem; /* 16px–17px */
    margin-bottom: 26px;
  }

  .signal-grid {
    grid-template-columns: repeat(2, 1fr);
    row-gap: 24px;
  }
  .signal-col:nth-child(3) {
    border-left: none;
    padding-left: 0;
  }
  
  .why-layout {
    grid-template-columns: 1fr;
    gap: 36px;
  }
  .why-left {
    border-right: none;
    padding-right: 0;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 24px;
  }
  
  .spec-row {
    grid-template-columns: 140px 110px 1fr 130px 140px;
    padding: 20px;
  }
  
  .footer-top-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 36px;
  }
}

@media (max-width: 860px) {
  .nav-desktop,
  .header-actions .btn-plan {
    display: none;
  }
  .menu-toggle {
    display: block;
  }
  
  .region-row {
    grid-template-columns: 1fr;
    gap: 16px;
    padding: 24px 0;
  }
  
  .device-row {
    grid-template-columns: 1fr auto;
    row-gap: 8px;
  }
  .device-desc {
    grid-column: 1 / -1;
  }
  
  .asym-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  
  .editorial-index-layout {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  .editorial-left {
    border-right: none;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 20px;
  }
  
  .article-row {
    grid-template-columns: 36px 1fr 32px;
  }
  .row-time {
    display: none;
  }
  
  .notes-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }
  
  .sitemap-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}

@media (max-width: 640px) {
  :root {
    --header-height: 62px;
  }
  body {
    font-size: 1rem;
  }
  .container,
  .article-container {
    padding-left: 18px;
    padding-right: 18px;
  }
  .site-section {
    padding: 60px 0;
  }
  
  .hero-section {
    padding: 36px 0 30px 0;
  }
  .hero-h1-primary {
    font-size: clamp(2.375rem, 8vw, 2.75rem); /* 38px–44px */
    margin-bottom: 8px;
  }
  .hero-h1-statement {
    font-size: clamp(2.375rem, 8.5vw, 2.875rem); /* 38px–46px */
    line-height: 1.15;
    margin-bottom: 16px;
  }
  .hero-h1-statement span {
    display: block; /* 移动端自然拆成两行，避免强行塞在一行 */
  }
  .hero-h1-sub {
    font-size: clamp(1.375rem, 5.5vw, 1.6875rem); /* 22px–27px */
    line-height: 1.35;
    margin-bottom: 18px;
  }
  .hero-desc {
    font-size: 1rem; /* 16px */
    line-height: 1.75;
    margin-bottom: 24px;
  }
  .hero-cta-group {
    flex-direction: column;
    align-items: stretch;
  }
  .hero-cta-group .btn {
    width: 100%;
  }
  
  .signal-grid {
    grid-template-columns: 1fr;
    gap: 18px;
  }
  .signal-col {
    border-left: none;
    padding: 0;
  }
  
  .capability-row {
    grid-template-columns: 1fr;
    gap: 8px;
    padding: 18px 0;
  }
  
  /* Mobile Pricing: Vertical Spec Rows */
  .spec-row {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    padding: 20px;
  }
  .spec-desc {
    padding-right: 0;
  }
  .spec-row .btn {
    width: 100%;
    margin-top: 8px;
  }
  
  .article-row {
    grid-template-columns: 28px 1fr 24px;
    padding: 18px 8px;
  }
  .row-title {
    font-size: 1rem;
  }
  
  .footer-top-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
}

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