/* ==================================================
   气泡云 (qipaoyun.lol) 第2套：液态气泡界面系统 CSS
   ================================================== */

:root {
  --bg: #F3F3F6;
  --surface: #FFFFFF;
  --surface-silver: #FBFBFC;
  --surface-soft: #ECEAF4;
  --text: #262932;
  --body-text: #606570;
  --muted: #90949C;
  
  --purple-gray-dark: #4C4F63;
  --purple-gray-mid: #6C7088;
  --purple-gray-light: #ECEAF4;
  
  --tech-purple: #7774A2;
  --tech-purple-dark: #5E5A88;
  
  --liquid-cyan: #5B929C;
  --liquid-cyan-dark: #457982;
  --liquid-cyan-light: #E7F0F1;
  
  --cold-silver: #C8CED6;
  --cold-silver-light: #EEF0F3;
  
  --copper-pink: #B27B69;
  --copper-pink-dark: #8D5E50;
  --copper-pink-light: #F4EAE7;
  
  --border: #D9DBE2;
  --border-dark: #C6C8D0;
  
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-liquid-1: 42px 58px 48px 52px / 52px 42px 58px 48px;
  --radius-liquid-2: 58px 42px 52px 48px / 42px 52px 48px 58px;
  --radius-liquid-3: 48px 52px 42px 58px / 58px 48px 52px 42px;
  
  --shadow-soft: 0 14px 48px rgba(38, 41, 50, 0.04);
  --shadow-hover: 0 18px 56px rgba(38, 41, 50, 0.08);
}

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

html {
  font-family: var(--font-main);
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.8;
  font-size: 16px;
  scroll-behavior: smooth;
}

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

a {
  color: var(--purple-gray-dark);
  text-decoration: none;
  transition: color 0.25s ease, opacity 0.25s ease;
}

a:hover {
  color: var(--liquid-cyan-dark);
}

a:focus-visible, button:focus-visible {
  outline: 2px solid var(--liquid-cyan);
  outline-offset: 3px;
  border-radius: 4px;
}

p {
  color: var(--body-text);
  line-height: 1.85;
  margin-bottom: 1.2rem;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--text);
  font-weight: 680;
  line-height: 1.35;
  letter-spacing: -0.01em;
}

h1 { font-size: 2.75rem; margin-bottom: 1rem; }
h2 { font-size: 2rem; margin-bottom: 1rem; }
h3 { font-size: 1.4rem; margin-bottom: 0.75rem; }

ul, ol {
  padding-left: 1.5rem;
  margin-bottom: 1.2rem;
  color: var(--body-text);
}

li {
  margin-bottom: 0.5rem;
}

.container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
  width: 100%;
}

/* Header & Nav */
.site-header {
  height: 72px;
  background: rgba(243, 243, 246, 0.94);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  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%;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

.logo-svg {
  width: 38px;
  height: 38px;
  flex-shrink: 0;
}

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

.brand-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--purple-gray-dark);
  line-height: 1.1;
  letter-spacing: 0.02em;
}

.brand-sub {
  font-size: 0.7rem;
  color: var(--muted);
  font-weight: 500;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 18px;
}

.nav-link {
  font-size: 0.92rem;
  color: var(--body-text);
  font-weight: 500;
  position: relative;
  padding: 6px 4px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
}

.nav-link:hover {
  color: var(--purple-gray-dark);
}

.nav-link.active {
  color: var(--purple-gray-dark);
  font-weight: 650;
}

.nav-active-dot {
  width: 8px;
  height: 8px;
  background-color: var(--liquid-cyan);
  border-radius: 4px 6px 5px 3px / 5px 3px 6px 4px;
  display: inline-block;
  animation: dotMorph 12s infinite ease-in-out;
}

.header-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 9px 20px;
  background-color: var(--purple-gray-dark);
  color: #ffffff !important;
  font-weight: 600;
  font-size: 0.9rem;
  border-radius: var(--radius-sm);
  transition: background-color 0.25s ease, transform 0.2s ease;
}

.header-cta:hover {
  background-color: var(--tech-purple-dark);
  transform: translateY(-1px);
}

/* Mobile Menu Toggle */
.mobile-menu-btn {
  display: none;
  background: none;
  border: 1px solid var(--border);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  color: var(--purple-gray-dark);
  font-weight: 600;
}

.mobile-nav-overlay {
  display: none;
  position: fixed;
  top: 72px;
  left: 0;
  width: 100%;
  height: calc(100vh - 72px);
  background: var(--bg);
  z-index: 999;
  padding: 24px;
  overflow-y: auto;
  border-top: 1px solid var(--border);
}

.mobile-nav-overlay.open {
  display: block;
}

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

.mobile-nav-links a {
  font-size: 1.1rem;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  font-weight: 500;
}

/* Common Section Layout */
.section {
  padding: 80px 0;
  position: relative;
}

.section-header {
  margin-bottom: 48px;
}

.section-tag {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--liquid-cyan-dark);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 8px;
  background: var(--liquid-cyan-light);
  padding: 4px 12px;
  border-radius: 20px;
}

.section-title {
  font-size: 2.1rem;
  color: var(--text);
  margin-bottom: 12px;
}

.section-subtitle {
  font-size: 1.15rem;
  color: var(--purple-gray-mid);
  font-weight: 400;
  max-width: 820px;
}

/* Liquid Fusion Components (Pure CSS) */
.liquid-tag-copper {
  background-color: var(--copper-pink-light);
  color: var(--copper-pink-dark);
  font-size: 0.82rem;
  font-weight: 650;
  padding: 3px 10px;
  border-radius: 12px;
  display: inline-block;
}

/* Hero Section */
.hero-section {
  padding: 60px 0 80px;
  min-height: 720px;
  position: relative;
  display: flex;
  align-items: center;
}

.hero-liquid-wrapper {
  position: relative;
  width: 100%;
  min-height: 560px;
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 36px;
  align-items: center;
}

.hero-main-content {
  z-index: 10;
  position: relative;
  padding-right: 20px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--purple-gray-light);
  padding: 6px 16px;
  border-radius: 30px;
  margin-bottom: 24px;
}

.hero-badge-text {
  font-size: 0.88rem;
  color: var(--purple-gray-dark);
  font-weight: 600;
}

.hero-h1 {
  font-size: 2.85rem;
  line-height: 1.25;
  color: var(--text);
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}

.hero-intro-text {
  font-size: 1.12rem;
  color: var(--body-text);
  margin-bottom: 32px;
  max-width: 620px;
  line-height: 1.85;
}

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

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  background-color: var(--liquid-cyan);
  color: #ffffff !important;
  font-weight: 650;
  border-radius: var(--radius-sm);
  transition: background-color 0.25s ease, transform 0.2s ease;
}

.btn-primary:hover {
  background-color: var(--liquid-cyan-dark);
  transform: translateY(-2px);
}

.btn-commercial {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  background-color: var(--purple-gray-dark);
  color: #ffffff !important;
  font-weight: 650;
  border-radius: var(--radius-sm);
  transition: background-color 0.25s ease, transform 0.2s ease;
}

.btn-commercial:hover {
  background-color: var(--tech-purple-dark);
  transform: translateY(-2px);
}

.hero-review-link {
  font-size: 0.95rem;
  color: var(--purple-gray-mid);
  font-weight: 600;
  margin-left: 8px;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.hero-review-link:hover {
  color: var(--liquid-cyan-dark);
}

/* Hero Liquid Bubble Visual Layout */
.hero-bubbles-container {
  position: relative;
  width: 100%;
  height: 520px;
}

.hero-fusion-zone {
  position: absolute;
  padding: 28px;
  box-shadow: var(--shadow-soft);
  transition: transform 0.4s ease, border-radius 0.4s ease;
  overflow: hidden;
}

.hero-fusion-zone:hover {
  transform: translateY(-4px) scale(1.008);
  box-shadow: var(--shadow-hover);
}

/* Zone 01: Plan & Data (Top Left) */
.hero-zone-01 {
  top: 10px;
  left: 0;
  width: 270px;
  height: 240px;
  background-color: var(--purple-gray-light);
  border-radius: var(--radius-liquid-1);
  border: 1px solid var(--border);
  z-index: 2;
  animation: liquidMorph1 14s ease-in-out infinite alternate;
}

/* Zone 02: Node & Region & Line (Right Largest) */
.hero-zone-02 {
  top: 60px;
  right: 0;
  width: 320px;
  height: 380px;
  background-color: var(--liquid-cyan-light);
  border-radius: var(--radius-liquid-2);
  border: 1px solid #C4DDE1;
  z-index: 3;
  animation: liquidMorph2 16s ease-in-out infinite alternate;
}

/* Zone 03: Client & Sub & Config (Bottom Left) */
.hero-zone-03 {
  bottom: 20px;
  left: 60px;
  width: 290px;
  height: 230px;
  background-color: var(--cold-silver-light);
  border-radius: var(--radius-liquid-3);
  border: 1px solid var(--border);
  z-index: 1;
  animation: liquidMorph3 12s ease-in-out infinite alternate;
}

/* Connecting Necks between Hero Zones */
.hero-neck-01-02 {
  position: absolute;
  top: 120px;
  right: 250px;
  width: 90px;
  height: 60px;
  background: linear-gradient(135deg, var(--purple-gray-light), var(--liquid-cyan-light));
  border-radius: 30px 40px 20px 50px;
  opacity: 0.85;
  z-index: 2;
  pointer-events: none;
}

.hero-neck-02-03 {
  position: absolute;
  bottom: 110px;
  right: 210px;
  width: 80px;
  height: 70px;
  background: linear-gradient(135deg, var(--liquid-cyan-light), var(--cold-silver-light));
  border-radius: 40px 20px 50px 30px;
  opacity: 0.85;
  z-index: 2;
  pointer-events: none;
}

.zone-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--purple-gray-dark);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.zone-desc {
  font-size: 0.88rem;
  color: var(--body-text);
  line-height: 1.6;
}

.zone-badge {
  font-size: 0.75rem;
  background: rgba(255,255,255,0.7);
  padding: 2px 8px;
  border-radius: 10px;
  color: var(--purple-gray-mid);
}

/* Section 01: Four-Concept Fused Island */
.fused-island-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  margin-bottom: 48px;
}

.fused-pair {
  position: relative;
  background: var(--surface-silver);
  border: 1px solid var(--border);
  border-radius: 28px;
  padding: 36px;
  box-shadow: var(--shadow-soft);
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.fused-pair-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px dashed var(--border);
  padding-bottom: 14px;
}

.concept-box {
  background: var(--surface);
  border-radius: 16px;
  padding: 20px;
  border: 1px solid var(--border);
  position: relative;
}

.concept-box.highlight-cyan {
  background: var(--liquid-cyan-light);
  border-color: #C4DDE1;
}

.concept-box.highlight-purple {
  background: var(--purple-gray-light);
  border-color: var(--border);
}

.concept-box h4 {
  font-size: 1.1rem;
  color: var(--purple-gray-dark);
  margin-bottom: 6px;
}

/* HTML Knowledge Table */
.knowledge-table-wrapper {
  overflow-x: auto;
  margin-top: 32px;
  background: var(--surface-silver);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 8px;
}

.knowledge-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.95rem;
}

.knowledge-table th {
  background-color: var(--purple-gray-dark);
  color: #ffffff;
  font-weight: 600;
  padding: 16px 20px;
  font-size: 0.92rem;
}

.knowledge-table th:first-child {
  border-top-left-radius: 10px;
}
.knowledge-table th:last-child {
  border-top-right-radius: 10px;
}

.knowledge-table td {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  color: var(--body-text);
  background: var(--surface);
}

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

.knowledge-table td strong {
  color: var(--text);
}

/* Section 02: Node & Region & Server Visual */
.node-region-container {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 32px;
  align-items: center;
  background: var(--surface-silver);
  border: 1px solid var(--border);
  border-radius: 32px;
  padding: 40px;
  position: relative;
}

.node-big-bubble {
  background: var(--liquid-cyan-light);
  border: 1px solid #C4DDE1;
  border-radius: 36px 48px 40px 44px;
  padding: 32px;
  position: relative;
}

.region-small-bubble {
  background: var(--purple-gray-light);
  border: 1px solid var(--border);
  border-radius: 32px 24px 36px 28px;
  padding: 24px;
}

.server-text-tag {
  display: inline-block;
  font-size: 0.8rem;
  color: var(--muted);
  background: var(--bg);
  padding: 4px 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  margin-top: 12px;
}

/* Section 03: Four Region Liquid Terms */
.four-regions-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.region-liquid-card {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 28px;
  transition: transform 0.25s ease;
}

.region-liquid-card:nth-child(1) {
  border-radius: 36px 24px 30px 40px;
  background: var(--purple-gray-light);
}
.region-liquid-card:nth-child(2) {
  border-radius: 24px 36px 40px 30px;
  background: var(--liquid-cyan-light);
}
.region-liquid-card:nth-child(3) {
  border-radius: 40px 30px 24px 36px;
  background: var(--cold-silver-light);
}
.region-liquid-card:nth-child(4) {
  border-radius: 30px 40px 36px 24px;
  background: var(--copper-pink-light);
}

.region-liquid-card:hover {
  transform: translateY(-3px);
}

/* Section 05: Three-Bubble Fused Structure (Client, Sub, Config) */
.three-bubble-structure {
  position: relative;
  background: var(--surface-silver);
  border: 1px solid var(--border);
  border-radius: 36px;
  padding: 44px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.client-bubble-large {
  background: var(--liquid-cyan-light);
  border: 1px solid #C4DDE1;
  border-radius: 44px 36px 52px 40px;
  padding: 36px;
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.node-inner-circle {
  background: var(--surface);
  border: 2px dashed var(--liquid-cyan);
  border-radius: 50%;
  width: 110px;
  height: 110px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--liquid-cyan-dark);
  margin-top: 16px;
  align-self: flex-end;
  text-align: center;
}

.sub-config-stack {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.sub-bubble-top {
  background: var(--purple-gray-light);
  border-radius: 32px 40px 24px 36px;
  padding: 24px;
  border: 1px solid var(--border);
}

.config-bubble-bottom {
  background: var(--cold-silver-light);
  border-radius: 24px 36px 40px 28px;
  padding: 24px;
  border: 1px solid var(--border);
}

.flow-step-num {
  display: inline-block;
  width: 26px;
  height: 26px;
  background: var(--purple-gray-dark);
  color: #fff;
  border-radius: 50%;
  text-align: center;
  line-height: 26px;
  font-size: 0.8rem;
  font-weight: 700;
  margin-right: 8px;
}

/* Section 06: Two Connected Large Bubbles (Clash & Clash Verge) */
.clash-fusion-wrapper {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
  position: relative;
}

.clash-bubble {
  background: var(--purple-gray-light);
  border: 1px solid var(--border);
  border-radius: 40px 52px 36px 48px;
  padding: 36px;
}

.clash-verge-bubble {
  background: var(--liquid-cyan-light);
  border: 1px solid #C4DDE1;
  border-radius: 52px 40px 48px 36px;
  padding: 36px;
}

/* Section 07: Device Liquid Island Group */
.device-island-group {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.device-island {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 28px;
  position: relative;
}

.device-island.win { background: var(--purple-gray-light); }
.device-island.mac { background: var(--cold-silver-light); }
.device-island.android { background: var(--liquid-cyan-light); }
.device-island.iphone { background: var(--copper-pink-light); }

/* Section 08: Two Liquid Knowledge Bubbles (DNS & System Proxy) */
.dns-proxy-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.dns-bubble {
  background: var(--liquid-cyan-light);
  border: 1px solid #C4DDE1;
  border-radius: 44px 32px 50px 38px;
  padding: 36px;
}

.proxy-bubble {
  background: var(--purple-gray-light);
  border: 1px solid var(--border);
  border-radius: 32px 44px 38px 50px;
  padding: 36px;
}

/* Section 09: Three Layer Fused Structure (AI & Streaming) */
.platform-fusion-structure {
  background: var(--surface-silver);
  border: 1px solid var(--border);
  border-radius: 36px;
  padding: 40px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.ai-layer {
  background: var(--purple-gray-light);
  border-radius: 24px;
  padding: 28px;
}

.shared-factor-bar {
  background: var(--copper-pink-light);
  border-radius: 20px;
  padding: 20px;
  text-align: center;
  font-weight: 650;
  color: var(--copper-pink-dark);
}

.streaming-layer {
  background: var(--liquid-cyan-light);
  border-radius: 24px;
  padding: 28px;
}

.platform-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
}

.chip {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--purple-gray-dark);
}

/* Section 10: Separated Bubbles Misconception Area */
.separated-concepts-grid {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.concept-not-equal-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 20px 28px;
  box-shadow: var(--shadow-soft);
}

.concept-left, .concept-right {
  font-size: 1.05rem;
  font-weight: 650;
  color: var(--purple-gray-dark);
  flex: 1;
}

.concept-right {
  text-align: right;
}

.not-equal-sign {
  width: 44px;
  height: 44px;
  background: var(--purple-gray-dark);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  font-weight: 700;
  flex-shrink: 0;
  margin: 0 20px;
}

/* Section 11: Knowledge Review Summary Card */
.review-summary-card {
  background: linear-gradient(135deg, var(--purple-gray-light) 0%, var(--liquid-cyan-light) 100%);
  border: 1fr solid var(--border);
  border-radius: 36px;
  padding: 48px;
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 40px;
  align-items: center;
  box-shadow: var(--shadow-soft);
}

.review-summary-left h3 {
  font-size: 1.8rem;
  margin-bottom: 16px;
}

/* Section 12: Liquid Price Band (液态价目带) */
.liquid-price-band-wrapper {
  background: var(--surface-silver);
  border: 1px solid var(--border);
  border-radius: 40px;
  padding: 40px;
  box-shadow: var(--shadow-soft);
  position: relative;
}

.liquid-price-band {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 20px;
  position: relative;
}

.price-plan-zone {
  padding: 32px 24px;
  border-radius: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  border: 1px solid var(--border);
  transition: transform 0.3s ease;
  position: relative;
}

.price-plan-zone:hover {
  transform: translateY(-4px);
}

/* Plan Specific Styling */
.plan-light {
  background: var(--surface-silver);
}

.plan-daily {
  background: var(--liquid-cyan-light);
  border-color: #C4DDE1;
}

.plan-master {
  background: var(--purple-gray-light);
  border: 2px solid var(--purple-gray-dark);
  transform: scale(1.03);
  z-index: 5;
}

.plan-high {
  background: var(--cold-silver-light);
}

.plan-long {
  background: var(--copper-pink-light);
  border-color: #E2C9C2;
}

.plan-badge-master {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--copper-pink-dark);
  color: #fff;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 4px 14px;
  border-radius: 12px;
  white-space: nowrap;
}

.plan-name {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--purple-gray-dark);
  margin-bottom: 6px;
}

.plan-traffic {
  font-size: 0.95rem;
  color: var(--purple-gray-mid);
  font-weight: 600;
  margin-bottom: 16px;
}

.plan-price-num {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--text);
  line-height: 1;
}

.plan-price-unit {
  font-size: 0.85rem;
  color: var(--muted);
}

.plan-features {
  list-style: none;
  padding: 0;
  margin: 20px 0;
  font-size: 0.88rem;
}

.plan-features li {
  margin-bottom: 8px;
  color: var(--body-text);
}

.plan-cta {
  display: block;
  text-align: center;
  padding: 10px 16px;
  background: var(--purple-gray-dark);
  color: #fff !important;
  font-weight: 650;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  transition: background 0.25s ease;
}

.plan-cta:hover {
  background: var(--tech-purple-dark);
}

/* Section 13: Knowledge Article Center (液态知识目录) */
.article-center-categories {
  display: flex;
  flex-direction: column;
  gap: 36px;
}

.category-knowledge-block {
  background: var(--surface-silver);
  border: 1px solid var(--border);
  border-radius: 28px;
  padding: 36px;
}

.category-block-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 14px;
}

.category-block-title {
  font-size: 1.4rem;
  color: var(--purple-gray-dark);
}

.article-list-rows {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.article-row-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.article-row-item:hover {
  border-color: var(--liquid-cyan);
  transform: translateX(4px);
}

.article-row-main {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  flex: 1;
}

.article-id-tag {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--liquid-cyan-dark);
  background: var(--liquid-cyan-light);
  padding: 4px 10px;
  border-radius: 8px;
  flex-shrink: 0;
}

.article-row-title-def {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.article-row-title {
  font-size: 1.05rem;
  font-weight: 650;
  color: var(--text);
}

.article-row-def {
  font-size: 0.88rem;
  color: var(--body-text);
}

.article-row-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 0.82rem;
  color: var(--muted);
  flex-shrink: 0;
}

/* Section 14: Knowledge FAQ (融合问答区) */
.faq-accordion-container {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item-fused {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 18px;
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.faq-question-btn {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 22px 28px;
  font-size: 1.08rem;
  font-weight: 650;
  color: var(--purple-gray-dark);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.faq-toggle-icon {
  font-size: 1.2rem;
  font-weight: 400;
  transition: transform 0.3s ease;
}

.faq-answer-content {
  padding: 0 28px 24px;
  background: var(--surface-silver);
  color: var(--body-text);
  font-size: 0.95rem;
  line-height: 1.8;
  border-top: 1px dashed var(--border);
}

.faq-item-fused.active .faq-toggle-icon {
  transform: rotate(45deg);
}

/* Page Specific Header (Category / Article / Standard) */
.page-hero-banner {
  background: linear-gradient(135deg, var(--purple-gray-light) 0%, var(--liquid-cyan-light) 100%);
  border-bottom: 1px solid var(--border);
  padding: 60px 0;
}

.breadcrumb-nav {
  font-size: 0.88rem;
  color: var(--muted);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb-nav a {
  color: var(--purple-gray-mid);
}

.breadcrumb-nav a:hover {
  color: var(--purple-gray-dark);
}

/* Article Layout */
.article-page-container {
  padding: 60px 0 100px;
}

.article-layout-grid {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 48px;
}

.article-main-body {
  max-width: 820px;
  background: var(--surface-silver);
  border: 1px solid var(--border);
  border-radius: 28px;
  padding: 48px;
}

.quick-conclusion-box {
  background: var(--surface-soft);
  border-left: 4px solid var(--liquid-cyan-dark);
  border-radius: 12px;
  padding: 24px;
  margin-bottom: 36px;
  position: relative;
  overflow: hidden;
}

.quick-conclusion-box h3 {
  font-size: 1.15rem;
  color: var(--purple-gray-dark);
  margin-bottom: 8px;
}

.article-content h2 {
  font-size: 1.65rem;
  margin-top: 2.2rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 8px;
}

.article-content h3 {
  font-size: 1.25rem;
  margin-top: 1.8rem;
  margin-bottom: 0.75rem;
}

.article-sidebar-toc {
  position: sticky;
  top: 100px;
  align-self: start;
  background: var(--surface-silver);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 24px;
}

.toc-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--purple-gray-dark);
  margin-bottom: 14px;
}

.toc-list {
  list-style: none;
  padding: 0;
  margin: 0;
  font-size: 0.88rem;
}

.toc-list li {
  margin-bottom: 8px;
}

.toc-list a {
  color: var(--body-text);
}

.toc-list a:hover {
  color: var(--purple-gray-dark);
}

/* Footer Section (深紫灰知识Footer) */
.site-footer {
  background-color: var(--purple-gray-dark);
  color: #F7F7F9;
  padding: 64px 0 32px;
  border-top: 1px solid var(--border-dark);
  position: relative;
  overflow: hidden;
}

.footer-bg-curve-1 {
  position: absolute;
  top: -100px;
  right: -100px;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(91, 146, 156, 0.06) 0%, rgba(0,0,0,0) 70%);
  border-radius: 50%;
  pointer-events: none;
}

.footer-bg-curve-2 {
  position: absolute;
  bottom: -50px;
  left: -50px;
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, rgba(178, 123, 105, 0.05) 0%, rgba(0,0,0,0) 70%);
  border-radius: 50%;
  pointer-events: none;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(4, 1fr);
  gap: 36px;
  margin-bottom: 48px;
}

.footer-brand p {
  color: #D2D3DD;
  font-size: 0.9rem;
  margin-top: 12px;
  max-width: 280px;
}

.footer-col-title {
  font-size: 1rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 18px;
  position: relative;
  display: inline-block;
}

.footer-col-title::after {
  content: '';
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--liquid-cyan);
  margin-top: 4px;
}

.footer-links {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-links li {
  margin-bottom: 10px;
}

.footer-links a {
  color: #D2D3DD;
  font-size: 0.88rem;
}

.footer-links a:hover {
  color: #ffffff;
}

.footer-friends-bar {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 24px;
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
  font-size: 0.85rem;
  color: #D2D3DD;
}

.footer-friends-bar a {
  color: #D2D3DD;
}

.footer-friends-bar a:hover {
  color: #ffffff;
}

.footer-bottom-copyright {
  text-align: center;
  font-size: 0.82rem;
  color: #90949C;
  border-top: 1px solid rgba(255,255,255,0.05);
  padding-top: 24px;
}

/* Animations */
@keyframes liquidMorph1 {
  0% { border-radius: 42px 58px 48px 52px / 52px 42px 58px 48px; }
  50% { border-radius: 58px 42px 52px 48px / 42px 52px 48px 58px; }
  100% { border-radius: 48px 52px 42px 58px / 58px 48px 52px 42px; }
}

@keyframes liquidMorph2 {
  0% { border-radius: 52px 48px 58px 42px / 48px 58px 42px 52px; }
  50% { border-radius: 42px 58px 48px 52px / 58px 42px 52px 48px; }
  100% { border-radius: 58px 42px 52px 48px / 42px 52px 48px 58px; }
}

@keyframes liquidMorph3 {
  0% { border-radius: 48px 52px 42px 58px / 58px 48px 52px 42px; }
  50% { border-radius: 52px 48px 58px 42px / 48px 58px 42px 52px; }
  100% { border-radius: 42px 58px 48px 52px / 52px 42px 58px 48px; }
}

@keyframes dotMorph {
  0%, 100% { border-radius: 4px 6px 5px 3px / 5px 3px 6px 4px; }
  50% { border-radius: 6px 4px 3px 5px / 3px 5px 4px 6px; }
}

/* Responsive Media Queries */
@media (max-width: 1100px) {
  .hero-liquid-wrapper {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .hero-bubbles-container {
    height: 440px;
  }
  .liquid-price-band {
    grid-template-columns: repeat(2, 1fr);
  }
  .plan-master {
    transform: none;
    grid-column: span 2;
  }
}

@media (max-width: 900px) {
  .main-nav { display: none; }
  .mobile-menu-btn { display: block; }
  
  .article-layout-grid {
    grid-template-columns: 1fr;
  }
  .article-sidebar-toc {
    display: none;
  }
  
  .fused-island-grid,
  .four-regions-grid,
  .three-bubble-structure,
  .clash-fusion-wrapper,
  .device-island-group,
  .dns-proxy-grid,
  .review-summary-card,
  .node-region-container {
    grid-template-columns: 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 600px) {
  h1 { font-size: 2.1rem; }
  h2 { font-size: 1.6rem; }
  
  .liquid-price-band {
    grid-template-columns: 1fr;
  }
  .plan-master {
    grid-column: span 1;
  }
  
  .hero-bubbles-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
    height: auto;
  }
  
  .hero-fusion-zone {
    position: relative;
    width: 100% !important;
    height: auto !important;
    top: auto !important;
    left: auto !important;
    right: auto !important;
    bottom: auto !important;
    border-radius: 20px !important;
  }
  
  .hero-neck-01-02, .hero-neck-02-03 {
    display: none;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
  }
  
  .concept-not-equal-row {
    flex-direction: column;
    gap: 10px;
    text-align: center;
  }
  .concept-right { text-align: center; }
  .not-equal-sign { margin: 8px 0; }
}

@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;
  }
}