/* ==========================================================================
   影子云官网 (yingzi.cyou) - 纯白云端高质感主题 CSS 样式表
   ========================================================================== */

:root {
  --bg-dark: #ffffff;
  --bg-surface: #f8fafc;
  --bg-card: #ffffff;
  
  --border-color: #e2e8f0;
  --border-focus: #0284c7;
  
  --primary-brand: #0284c7;
  --primary-dark: #0369a1;
  --accent-cyan: #06b6d4;
  --accent-blue: #2563eb;
  
  --text-main: #0f172a;
  --text-muted: #475569;
  --text-light: #94a3b8;
  
  --gradient-btn: linear-gradient(135deg, #0284c7 0%, #2563eb 100%);
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 12px 32px -4px rgba(2, 132, 199, 0.08), 0 4px 12px rgba(0, 0, 0, 0.02);
  --shadow-hover: 0 20px 40px -8px rgba(2, 132, 199, 0.16), 0 8px 20px rgba(0, 0, 0, 0.04);
  
  --radius-sm: 10px;
  --radius-md: 18px;
  --radius-lg: 28px;
  --radius-full: 9999px;
  
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  font-family: var(--font-main);
  background-color: var(--bg-dark);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body {
  overflow-x: hidden;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg-dark);
  position: relative;
}

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

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

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

/* 背景云朵与飞机艺术装饰图层 */
.background-decorations {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  pointer-events: none;
  z-index: 0;
}

.bg-cloud-item {
  position: absolute;
  fill: #e0f2fe;
  opacity: 0.55;
  filter: drop-shadow(0 10px 20px rgba(2, 132, 199, 0.06));
  animation: floatCloudBg 26s infinite ease-in-out alternate;
}

.cloud-p1 {
  top: 100px;
  left: -30px;
  width: 240px;
}

.cloud-p2 {
  top: 450px;
  right: -40px;
  width: 300px;
  animation-delay: -6s;
  animation-duration: 32s;
}

.cloud-p3 {
  top: 1350px;
  left: 5%;
  width: 260px;
  animation-delay: -12s;
}

.cloud-p4 {
  top: 2300px;
  right: 6%;
  width: 280px;
  animation-delay: -18s;
}

.bg-plane-item {
  position: absolute;
  fill: var(--primary-brand);
  opacity: 0.18;
  filter: drop-shadow(0 4px 10px rgba(2, 132, 199, 0.15));
  animation: floatPlaneBg 22s ease-in-out infinite alternate;
}

.plane-p1 {
  top: 160px;
  right: 14%;
  width: 54px;
  height: 54px;
  transform: rotate(-12deg);
}

.plane-p2 {
  top: 920px;
  left: 6%;
  width: 64px;
  height: 64px;
  transform: rotate(25deg);
  animation-delay: -8s;
}

.plane-p3 {
  top: 1850px;
  right: 8%;
  width: 48px;
  height: 48px;
  transform: rotate(-35deg);
  animation-delay: -14s;
}

@keyframes floatCloudBg {
  0% { transform: translateX(0px) translateY(0px); }
  50% { transform: translateX(35px) translateY(-18px); }
  100% { transform: translateX(-25px) translateY(12px); }
}

@keyframes floatPlaneBg {
  0% { transform: translateY(0px) rotate(-12deg) scale(1); }
  50% { transform: translateY(-28px) rotate(-4deg) scale(1.06); }
  100% { transform: translateY(18px) rotate(-18deg) scale(0.96); }
}

/* Containers */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

section {
  padding: 96px 0;
  position: relative;
}

/* Header Navbar */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 78px;
}

/* 品牌 Logo 统一样式 (确保与右图白底蓝色云朵一致) */
.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--text-main);
}

.brand-logo img, .footer-brand img {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  background-color: #ffffff;
  border: 1px solid #7dd3fc;
  box-shadow: 0 2px 10px rgba(56, 189, 248, 0.15);
  object-fit: contain;
}

.brand-title {
  background: var(--gradient-btn);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 900;
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 30px;
  list-style: none;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.96rem;
  font-weight: 600;
}

.nav-links a:hover {
  color: var(--primary-brand);
}

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

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 11px 26px;
  font-size: 0.95rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  transition: var(--transition);
  cursor: pointer;
  border: 1px solid transparent;
  gap: 8px;
}

.btn-primary {
  background: var(--gradient-btn);
  color: #ffffff;
  box-shadow: 0 6px 20px rgba(2, 132, 199, 0.28);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 28px rgba(2, 132, 199, 0.4);
  color: #ffffff;
}

.btn-recommend {
  background: #f0f9ff;
  color: var(--primary-brand);
  border: 1px solid #bae6fd;
}

.btn-recommend:hover {
  background: var(--primary-brand);
  color: #ffffff;
  border-color: var(--primary-brand);
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(2, 132, 199, 0.25);
}

.btn-outline {
  background: #ffffff;
  color: var(--text-main);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.btn-outline:hover {
  border-color: var(--primary-brand);
  color: var(--primary-brand);
  background: #f0f9ff;
}

.btn-lg {
  padding: 15px 36px;
  font-size: 1.08rem;
}

/* Section Header */
.section-header {
  text-align: center;
  max-width: 740px;
  margin: 0 auto 60px auto;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  background: #e0f2fe;
  color: var(--primary-brand);
  border-radius: var(--radius-full);
  font-size: 0.88rem;
  font-weight: 700;
  margin-bottom: 18px;
}

.section-title {
  font-size: 2.4rem;
  font-weight: 900;
  color: var(--text-main);
  line-height: 1.3;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}

.section-desc {
  font-size: 1.12rem;
  color: var(--text-muted);
}

/* Hero Section */
.hero-section {
  padding: 100px 0 84px 0;
  text-align: center;
  background: radial-gradient(circle at 50% 20%, #e0f2fe 0%, #ffffff 75%);
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 22px;
  background: #ffffff;
  border: 1px solid #bae6fd;
  border-radius: var(--radius-full);
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--primary-brand);
  margin-bottom: 30px;
  box-shadow: 0 4px 16px rgba(2, 132, 199, 0.08);
}

.hero-title {
  font-size: 3.8rem;
  font-weight: 900;
  line-height: 1.16;
  letter-spacing: -1.2px;
  margin-bottom: 26px;
  color: var(--text-main);
}

.hero-title .highlight {
  background: var(--gradient-btn);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 820px;
  margin: 0 auto 44px auto;
  line-height: 1.8;
}

.hero-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  margin-bottom: 60px;
  flex-wrap: wrap;
}

.hero-features {
  display: flex;
  justify-content: center;
  gap: 40px;
  flex-wrap: wrap;
  padding-top: 36px;
  border-top: 1px solid var(--border-color);
}

.hero-feature-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--text-muted);
}

.hero-feature-item svg {
  color: var(--primary-brand);
  width: 22px;
  height: 22px;
}

/* Pricing Grid */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 26px;
  margin-top: 40px;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  position: relative;
  display: flex;
  flex-direction: column;
  transition: var(--transition);
  box-shadow: var(--shadow-md);
}

.pricing-card:hover {
  transform: translateY(-8px);
  border-color: var(--border-focus);
  box-shadow: var(--shadow-hover);
}

.pricing-card.featured {
  border: 2px solid var(--primary-brand);
  background: linear-gradient(180deg, #f0f9ff 0%, #ffffff 100%);
  box-shadow: 0 16px 36px -8px rgba(2, 132, 199, 0.18);
}

.popular-badge {
  position: absolute;
  top: -14px;
  right: 28px;
  background: var(--gradient-btn);
  color: #ffffff;
  font-size: 0.78rem;
  font-weight: 800;
  padding: 4px 16px;
  border-radius: var(--radius-full);
  letter-spacing: 0.5px;
}

.plan-name {
  font-size: 1.4rem;
  font-weight: 800;
  margin-bottom: 8px;
  color: var(--text-main);
}

.plan-desc {
  font-size: 0.92rem;
  color: var(--text-muted);
  margin-bottom: 22px;
  min-height: 44px;
}

.plan-price {
  font-size: 2.6rem;
  font-weight: 900;
  color: var(--text-main);
  margin-bottom: 26px;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.plan-price span.unit {
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 500;
}

.plan-price span.currency {
  font-size: 1.5rem;
  color: var(--primary-brand);
}

.plan-features {
  list-style: none;
  margin-bottom: 34px;
  flex-grow: 1;
}

.plan-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.plan-features li svg {
  color: var(--primary-brand);
  flex-shrink: 0;
}

/* Feature Cards Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 26px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 34px;
  transition: var(--transition);
  box-shadow: var(--shadow-md);
}

.feature-card:hover {
  border-color: var(--border-focus);
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.feature-icon {
  width: 58px;
  height: 58px;
  border-radius: var(--radius-md);
  background: #e0f2fe;
  color: var(--primary-brand);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
}

.feature-icon svg {
  width: 28px;
  height: 28px;
}

.feature-title {
  font-size: 1.3rem;
  font-weight: 800;
  margin-bottom: 12px;
  color: var(--text-main);
}

.feature-text {
  font-size: 0.98rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* Article Hub Section */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 28px;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 32px;
  display: flex;
  flex-direction: column;
  transition: var(--transition);
  box-shadow: var(--shadow-md);
}

.article-card:hover {
  border-color: var(--border-focus);
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.85rem;
  color: var(--primary-brand);
  margin-bottom: 12px;
  font-weight: 700;
}

.article-meta span.date {
  color: var(--text-light);
  font-weight: 500;
}

.article-card-title {
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
  line-height: 1.45;
}

.article-card-title a {
  color: var(--text-main);
}

.article-card-title a:hover {
  color: var(--primary-brand);
}

.article-summary {
  font-size: 0.96rem;
  color: var(--text-muted);
  margin-bottom: 24px;
  line-height: 1.7;
  flex-grow: 1;
}

.article-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.94rem;
  font-weight: 700;
  color: var(--primary-brand);
}

.article-link:hover {
  gap: 10px;
}

/* Reviews Section */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  box-shadow: var(--shadow-md);
}

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

.user-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--gradient-btn);
  color: #ffffff;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.15rem;
}

.user-info .name {
  font-weight: 800;
  color: var(--text-main);
  font-size: 1.05rem;
}

.user-info .role {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.stars {
  color: #f59e0b;
  font-size: 0.95rem;
  letter-spacing: 2px;
}

.review-text {
  font-size: 0.96rem;
  color: var(--text-muted);
  line-height: 1.68;
  font-style: italic;
}

/* FAQ Accordion */
.faq-list {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

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

.faq-item[open] {
  border-color: var(--border-focus);
}

.faq-question {
  padding: 22px 28px;
  font-weight: 800;
  font-size: 1.08rem;
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  list-style: none;
}

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

.faq-question::after {
  content: "+";
  font-size: 1.5rem;
  color: var(--primary-brand);
  transition: var(--transition);
}

.faq-item[open] .faq-question::after {
  content: "−";
}

.faq-answer {
  padding: 0 28px 24px 28px;
  color: var(--text-muted);
  font-size: 0.98rem;
  line-height: 1.75;
}

/* Article Detail Pages Styling */
.article-detail-container {
  max-width: 880px;
  margin: 40px auto 80px auto;
  padding: 0 24px;
}

.article-header {
  margin-bottom: 36px;
  text-align: center;
}

.article-title-lg {
  font-size: 2.5rem;
  font-weight: 900;
  color: var(--text-main);
  line-height: 1.3;
  margin-bottom: 16px;
}

.article-body {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 44px;
  font-size: 1.08rem;
  line-height: 1.9;
  color: #334155;
  box-shadow: var(--shadow-md);
}

.article-body h2 {
  font-size: 1.65rem;
  font-weight: 800;
  color: var(--text-main);
  margin: 38px 0 18px 0;
  padding-bottom: 10px;
  border-bottom: 2px solid #f1f5f9;
}

.article-body h3 {
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--primary-brand);
  margin: 26px 0 14px 0;
}

.article-body p {
  margin-bottom: 22px;
}

.article-body ul, .article-body ol {
  margin: 0 0 26px 26px;
}

.article-body li {
  margin-bottom: 10px;
}

.article-body blockquote {
  border-left: 4px solid var(--primary-brand);
  background: #f0f9ff;
  padding: 18px 24px;
  margin: 26px 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-style: italic;
  color: #0369a1;
}

.article-cta-box {
  background: linear-gradient(135deg, #e0f2fe 0%, #f0f9ff 100%);
  border: 1px solid #bae6fd;
  border-radius: var(--radius-md);
  padding: 34px;
  text-align: center;
  margin: 40px 0;
}

.article-cta-box h3 {
  font-size: 1.45rem;
  color: var(--text-main);
  margin-bottom: 10px;
}

.article-cta-box p {
  color: var(--text-muted);
  margin-bottom: 20px;
}

.article-navigation {
  display: flex;
  justify-content: space-between;
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
}

/* Footer & PBN Links (Core Requirement) */
.site-footer {
  background: #f8fafc;
  border-top: 1px solid var(--border-color);
  padding: 56px 0 32px 0;
  margin-top: auto;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 24px;
  text-align: center;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-main);
}

/* PBN Friendly Links Zone (任务 2：页脚 PBN 权重管道) */
.pbn-links-area {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
  margin-top: 14px;
  padding-top: 18px;
  border-top: 1px solid #e2e8f0;
  font-size: 0.85rem;
  color: var(--text-light);
}

.pbn-links-label {
  color: var(--text-muted);
  font-weight: 600;
}

.pbn-link-item {
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 500;
  transition: var(--transition);
}

.pbn-link-item:hover {
  color: var(--primary-brand);
  text-decoration: underline;
}

/* Responsive */
@media (max-width: 992px) {
  .hero-title {
    font-size: 3rem;
  }
  .nav-links {
    display: none;
  }
}

@media (max-width: 640px) {
  .hero-title {
    font-size: 2.2rem;
  }
  .section-title {
    font-size: 1.8rem;
  }
  .article-body {
    padding: 26px;
  }
}