/* 吹雪云 (chuixueyun.cfd) - Global Stylesheet */

:root {
  --bg-primary: #070a12;
  --bg-secondary: #0f172a;
  --bg-card: rgba(30, 41, 59, 0.7);
  --bg-card-hover: rgba(47, 63, 94, 0.8);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-highlight: rgba(56, 189, 248, 0.3);
  
  --primary-cyan: #38bdf8;
  --primary-blue: #3b82f6;
  --accent-purple: #8b5cf6;
  --gradient-glow: linear-gradient(135deg, #00f2fe 0%, #4facfe 50%, #6157ff 100%);
  --gradient-btn: linear-gradient(135deg, #2563eb 0%, #0284c7 100%);
  --gradient-btn-hover: linear-gradient(135deg, #1d4ed8 0%, #0369a1 100%);
  --gradient-accent-text: linear-gradient(135deg, #7dd3fc 0%, #38bdf8 50%, #a855f7 100%);

  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 30px rgba(56, 189, 248, 0.25);
  
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 24px;

  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

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

body {
  overflow-x: hidden;
  background: radial-gradient(circle at 50% 0%, #1e293b 0%, #070a12 70%);
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
  transition: all 0.25s ease;
}

/* Header & Nav */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  backdrop-filter: blur(16px);
  background: rgba(7, 10, 18, 0.85);
  border-bottom: 1px solid var(--border-color);
}

.nav-container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-main);
}

.brand-logo {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  object-fit: cover;
  box-shadow: 0 0 15px rgba(56, 189, 248, 0.4);
}

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

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
  list-style: none;
}

.nav-link {
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 500;
}

.nav-link:hover {
  color: var(--primary-cyan);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.8rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.7rem 1.4rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  cursor: pointer;
  border: none;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.btn-primary {
  background: var(--gradient-btn);
  color: #fff;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
  background: var(--gradient-btn-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(56, 189, 248, 0.5);
}

.btn-recommend {
  background: rgba(56, 189, 248, 0.12);
  color: var(--primary-cyan);
  border: 1px solid var(--border-highlight);
}

.btn-recommend:hover {
  background: rgba(56, 189, 248, 0.25);
  transform: translateY(-2px);
}

.btn-lg {
  padding: 0.9rem 2.2rem;
  font-size: 1.05rem;
  border-radius: var(--radius-md);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text-main);
  font-size: 1.6rem;
  cursor: pointer;
}

/* Container */
.container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Section Title */
.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 3.5rem auto;
}

.section-tag {
  display: inline-block;
  padding: 0.35rem 1rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--primary-cyan);
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  border-radius: 50px;
  margin-bottom: 1rem;
}

.section-title {
  font-size: 2.2rem;
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: 1rem;
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 1.05rem;
}

/* Hero Section */
.hero {
  padding: 10rem 0 5rem 0;
  position: relative;
}

.hero-content {
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1.2rem;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  border-radius: 50px;
  font-size: 0.9rem;
  color: var(--primary-cyan);
  margin-bottom: 1.5rem;
}

.hero-title {
  font-size: 3.4rem;
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -1px;
  margin-bottom: 1.5rem;
}

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

.hero-description {
  font-size: 1.2rem;
  color: var(--text-muted);
  max-width: 720px;
  margin: 0 auto 2.5rem auto;
}

.hero-ctas {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  flex-wrap: wrap;
  margin-bottom: 4rem;
}

.hero-features-bar {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  background: var(--bg-card);
  padding: 1.5rem 2rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  backdrop-filter: blur(10px);
}

.hero-stat-item {
  text-align: center;
}

.hero-stat-val {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--primary-cyan);
}

.hero-stat-lbl {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Features Grid */
.features-section {
  padding: 5rem 0;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 2.2rem;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

.feature-card:hover {
  transform: translateY(-5px);
  border-color: var(--border-highlight);
  box-shadow: var(--shadow-glow);
}

.feature-icon {
  width: 54px;
  height: 54px;
  border-radius: 12px;
  background: rgba(56, 189, 248, 0.15);
  color: var(--primary-cyan);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 1.4rem;
}

.feature-title {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.feature-desc {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Pricing Section */
.pricing-section {
  padding: 5rem 0;
}

.pricing-tabs {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 3rem;
}

.tab-btn {
  padding: 0.8rem 1.8rem;
  border-radius: 50px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.3s ease;
}

.tab-btn.active {
  background: var(--gradient-btn);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.pricing-content-tab {
  display: none;
}

.pricing-content-tab.active {
  display: block;
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 2rem 1.5rem;
  text-align: center;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  transition: all 0.3s ease;
}

.pricing-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-highlight);
}

.pricing-card.featured {
  border-color: var(--primary-cyan);
  box-shadow: var(--shadow-glow);
  background: rgba(30, 58, 138, 0.3);
}

.pricing-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gradient-glow);
  color: #000;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 0.2rem 0.8rem;
  border-radius: 20px;
  text-transform: uppercase;
}

.pricing-name {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.pricing-traffic {
  color: var(--primary-cyan);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.pricing-price {
  font-size: 2.2rem;
  font-weight: 900;
  margin-bottom: 1.5rem;
}

.pricing-price span {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 400;
}

.pricing-features {
  list-style: none;
  text-align: left;
  margin-bottom: 1.8rem;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.pricing-features li {
  margin-bottom: 0.6rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.pricing-features li i {
  color: var(--primary-cyan);
}

/* Articles Section */
.articles-section {
  padding: 5rem 0;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 2rem;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all 0.3s ease;
}

.article-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-highlight);
}

.article-tag {
  font-size: 0.8rem;
  color: var(--primary-cyan);
  font-weight: 600;
  margin-bottom: 0.75rem;
  text-transform: uppercase;
}

.article-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  line-height: 1.4;
}

.article-excerpt {
  font-size: 0.92rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.article-readmore {
  color: var(--primary-cyan);
  font-weight: 600;
  font-size: 0.9rem;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

/* Testimonials / Reviews */
.reviews-section {
  padding: 5rem 0;
}

.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.8rem;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.8rem;
}

.review-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--gradient-btn);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
  color: #fff;
}

.user-info h4 {
  font-size: 1rem;
  font-weight: 700;
}

.user-info p {
  font-size: 0.8rem;
  color: var(--text-dim);
}

.stars {
  color: #f59e0b;
  margin-bottom: 0.8rem;
  font-size: 0.9rem;
}

.review-text {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* FAQ Section */
.faq-section {
  padding: 5rem 0;
}

.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
  overflow: hidden;
}

.faq-question {
  width: 100%;
  padding: 1.25rem 1.5rem;
  background: none;
  border: none;
  text-align: left;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  padding: 0 1.5rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.faq-item.active .faq-answer {
  padding: 0 1.5rem 1.25rem 1.5rem;
  max-height: 300px;
}

.faq-icon {
  transition: transform 0.3s ease;
}

.faq-item.active .faq-icon {
  transform: rotate(180deg);
}

/* Article Detail Page Layout */
.article-page {
  padding: 8rem 0 6rem 0;
}

.article-container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-dim);
  margin-bottom: 2rem;
}

.breadcrumb a:hover {
  color: var(--primary-cyan);
}

.article-header {
  margin-bottom: 3rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 2rem;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 1rem;
}

.article-body {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #cbd5e1;
}

.article-body h2 {
  font-size: 1.7rem;
  margin: 2.5rem 0 1.2rem 0;
  color: var(--text-main);
  border-left: 4px solid var(--primary-cyan);
  padding-left: 0.8rem;
}

.article-body h3 {
  font-size: 1.3rem;
  margin: 1.8rem 0 1rem 0;
  color: var(--text-main);
}

.article-body p {
  margin-bottom: 1.4rem;
}

.article-body ul, .article-body ol {
  margin-bottom: 1.5rem;
  padding-left: 1.8rem;
}

.article-body li {
  margin-bottom: 0.5rem;
}

.article-body blockquote {
  background: rgba(56, 189, 248, 0.08);
  border-left: 4px solid var(--primary-cyan);
  padding: 1.2rem 1.5rem;
  margin: 2rem 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: #e2e8f0;
}

.cta-box {
  background: linear-gradient(135deg, rgba(30, 58, 138, 0.4) 0%, rgba(15, 23, 42, 0.8) 100%);
  border: 1px solid var(--border-highlight);
  border-radius: var(--radius-md);
  padding: 2.5rem;
  text-align: center;
  margin: 3.5rem 0;
}

.cta-box h3 {
  font-size: 1.6rem;
  margin-bottom: 1rem;
}

.cta-box p {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.internal-nav {
  display: flex;
  justify-content: space-between;
  gap: 1.5rem;
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.nav-box {
  flex: 1;
  background: var(--bg-card);
  padding: 1.2rem 1.5rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

.nav-box label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-dim);
  margin-bottom: 0.3rem;
}

.nav-box a {
  font-weight: 600;
  color: var(--primary-cyan);
  font-size: 0.95rem;
}

/* FOOTER PBN Area - Task 2 Requirements */
footer {
  background: #05070d;
  border-top: 1px solid var(--border-color);
  padding: 3rem 0 2rem 0;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-content {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.footer-brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text-main);
}

.footer-brand img {
  width: 24px;
  height: 24px;
}

.footer-desc {
  color: var(--text-dim);
  max-width: 600px;
  margin: 0 auto 1.5rem auto;
  font-size: 0.85rem;
}

/* Low-profile, sleek friendship links area */
.friendly-links {
  margin: 1.5rem auto 1.5rem auto;
  padding: 1rem 0;
  border-top: 1px dashed rgba(255, 255, 255, 0.08);
  border-bottom: 1px dashed rgba(255, 255, 255, 0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
  font-size: 0.82rem;
  color: var(--text-dim);
}

.friendly-links label {
  color: var(--text-dim);
  font-weight: 500;
}

.friendly-links a {
  color: #94a3b8;
  transition: color 0.2s ease;
}

.friendly-links a:hover {
  color: var(--primary-cyan);
}

.copyright {
  color: var(--text-dim);
  font-size: 0.8rem;
  margin-top: 1rem;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background: var(--primary-cyan);
  color: #000;
  padding: 0.8rem 1.5rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.4);
  transform: translateY(100px);
  opacity: 0;
  transition: all 0.3s ease;
  z-index: 2000;
}

.toast.show {
  transform: translateY(0);
  opacity: 1;
}

/* Mobile responsive */
@media (max-width: 900px) {
  .hero-title {
    font-size: 2.4rem;
  }
  .nav-links {
    display: none;
  }
  .mobile-menu-btn {
    display: block;
  }
  .nav-links.mobile-active {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: #0f172a;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
  }
  .internal-nav {
    flex-direction: column;
  }
}