/* ===================================================================
   TAG Internet - 烈焰橙红与黑耀深渊流光极客视觉设计系统 (2026)
   Theme: Obsidian Abyss (#0b0a09) & Flame Amber Glow (#ff6b35 -> #f7c59f)
   =================================================================== */

:root {
  --bg-primary: #0b0a09;
  --bg-secondary: #12100e;
  --bg-tertiary: #191613;
  --bg-card: rgba(22, 19, 17, 0.72);
  --bg-card-hover: rgba(32, 27, 23, 0.9);
  
  /* Flame Amber Gradient Palette */
  --flame-primary: #ff6b35;
  --flame-secondary: #f7c59f;
  --flame-hot: #ff4500;
  --flame-amber: #ff9f1c;
  --flame-glow: rgba(255, 107, 53, 0.4);
  --flame-glow-soft: rgba(255, 107, 53, 0.15);
  --flame-gradient: linear-gradient(135deg, #ff6b35 0%, #f7c59f 100%);
  --flame-gradient-hot: linear-gradient(135deg, #ff4500 0%, #ff6b35 50%, #f7c59f 100%);
  
  /* Borders & Glassmorphism */
  --border-glass: rgba(255, 107, 53, 0.18);
  --border-glass-bright: rgba(255, 107, 53, 0.48);
  --border-card: rgba(255, 255, 255, 0.08);
  
  /* Typography Colors */
  --text-main: #fcfcfd;
  --text-muted: #a6a3a0;
  --text-sub: #787470;
  --text-highlight: #ff8c5a;
  
  /* Fonts */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", Consolas, "Liberation Mono", Menlo, Courier, monospace;

  /* Shadows */
  --shadow-glow: 0 0 35px rgba(255, 107, 53, 0.28);
  --shadow-card: 0 16px 40px rgba(0, 0, 0, 0.6);
  --shadow-button: 0 8px 25px rgba(255, 107, 53, 0.35);

  --transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-primary);
  color: var(--text-main);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  line-height: 1.65;
  background-color: var(--bg-primary);
  background-image: 
    radial-gradient(circle at 50% 0%, rgba(255, 107, 53, 0.12) 0%, transparent 60%),
    radial-gradient(circle at 10% 40%, rgba(255, 69, 0, 0.05) 0%, transparent 40%),
    radial-gradient(circle at 90% 70%, rgba(247, 197, 159, 0.04) 0%, transparent 40%),
    linear-gradient(to bottom, rgba(11, 10, 9, 0.98), #0b0a09);
  background-attachment: fixed;
  overflow-x: hidden;
  min-height: 100vh;
}

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

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

ul {
  list-style: none;
}

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

/* Typography Helpers */
.text-gradient {
  background: var(--flame-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

.text-mono {
  font-family: var(--font-mono);
}

/* Section Header */
.section-header {
  text-align: center;
  max-width: 800px;
  margin: 0 auto 60px;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(255, 107, 53, 0.08);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--flame-secondary);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 16px;
  box-shadow: 0 0 15px rgba(255, 107, 53, 0.1);
}

.section-tag .pulse-dot {
  width: 7px;
  height: 7px;
  background-color: var(--flame-primary);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--flame-primary);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

.section-title {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 18px;
  line-height: 1.25;
}

.section-desc {
  font-size: 1.1rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* Floating Glass Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: rgba(11, 10, 9, 0.82);
  border-bottom: 1px solid rgba(255, 107, 53, 0.12);
  transition: var(--transition);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.45rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-main);
}

.brand-logo .logo-icon {
  width: 36px;
  height: 36px;
  background: var(--flame-gradient);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #0b0a09;
  font-weight: 900;
  box-shadow: 0 0 20px rgba(255, 107, 53, 0.45);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-link {
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 500;
  position: relative;
  padding: 6px 0;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-main);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--flame-gradient);
  transition: width 0.3s ease;
  box-shadow: 0 0 8px var(--flame-primary);
}

.nav-link:hover::after {
  width: 100%;
}

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

/* Button Styles */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 26px;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition);
  border: 1px solid transparent;
  text-align: center;
  white-space: nowrap;
}

.btn-primary {
  background: var(--flame-gradient);
  color: #0b0a09;
  font-weight: 700;
  box-shadow: var(--shadow-button);
  position: relative;
  overflow: hidden;
}

.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.35), transparent);
  transition: 0.6s ease;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 30px rgba(255, 107, 53, 0.55);
}

.btn-primary:hover::before {
  left: 100%;
}

.btn-outline {
  background: rgba(255, 255, 255, 0.03);
  border-color: var(--border-glass);
  color: var(--text-main);
  backdrop-filter: blur(8px);
}

.btn-outline:hover {
  background: rgba(255, 107, 53, 0.1);
  border-color: var(--flame-primary);
  color: var(--flame-secondary);
  box-shadow: 0 0 20px rgba(255, 107, 53, 0.25);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 8px 18px;
  font-size: 0.88rem;
  border-radius: var(--radius-sm);
}

.btn-lg {
  padding: 16px 36px;
  font-size: 1.05rem;
}

/* Hero Section */
.hero-section {
  position: relative;
  padding: 100px 0 80px;
  text-align: center;
  overflow: hidden;
}

.hero-bg-glow {
  position: absolute;
  top: 15%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 700px;
  height: 400px;
  background: radial-gradient(ellipse at center, rgba(255, 107, 53, 0.22) 0%, transparent 70%);
  filter: blur(70px);
  z-index: -1;
  pointer-events: none;
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: rgba(255, 107, 53, 0.08);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-full);
  padding: 8px 22px;
  margin-bottom: 28px;
  font-size: 0.9rem;
  color: var(--flame-secondary);
  box-shadow: 0 0 25px rgba(255, 107, 53, 0.15);
}

.hero-pill .fire-icon {
  font-size: 1.1rem;
}

.hero-title {
  font-size: 3.75rem;
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 860px;
  margin: 0 auto 40px;
  line-height: 1.8;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  margin-bottom: 50px;
  flex-wrap: wrap;
}

.hero-status-bar {
  display: inline-flex;
  align-items: center;
  gap: 24px;
  background: rgba(22, 19, 17, 0.6);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-full);
  padding: 12px 30px;
  font-size: 0.9rem;
  color: var(--text-muted);
  box-shadow: var(--shadow-card);
}

.status-item {
  display: flex;
  align-items: center;
  gap: 8px;
}

.status-item strong {
  color: var(--text-main);
  font-family: var(--font-mono);
}

.status-dot {
  width: 8px;
  height: 8px;
  background-color: #10b981;
  border-radius: 50%;
  box-shadow: 0 0 8px #10b981;
}

/* Feature Matrix Cards */
.features-section {
  padding: 90px 0;
  position: relative;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.glass-card {
  background: var(--bg-card);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  padding: 36px 30px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-card);
}

.glass-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--flame-gradient);
  opacity: 0;
  transition: var(--transition);
}

.glass-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-glass-bright);
  background: var(--bg-card-hover);
  box-shadow: var(--shadow-glow), var(--shadow-card);
}

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

.card-icon-wrapper {
  width: 58px;
  height: 58px;
  background: rgba(255, 107, 53, 0.1);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  color: var(--flame-primary);
  margin-bottom: 24px;
  box-shadow: 0 0 20px rgba(255, 107, 53, 0.15);
}

.card-title {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 14px;
  color: var(--text-main);
}

.card-desc {
  color: var(--text-muted);
  font-size: 0.98rem;
  line-height: 1.7;
  margin-bottom: 20px;
}

.card-metric-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  padding-top: 18px;
}

.metric-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.88rem;
  color: var(--text-sub);
}

.metric-value {
  color: var(--flame-secondary);
  font-family: var(--font-mono);
  font-weight: 600;
}

/* Pricing Section */
.pricing-section {
  padding: 90px 0;
  background: linear-gradient(180deg, transparent, rgba(22, 19, 17, 0.4) 50%, transparent);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  transition: var(--transition);
  box-shadow: var(--shadow-card);
}

.pricing-card.popular {
  border-color: var(--flame-primary);
  background: rgba(30, 24, 20, 0.85);
  box-shadow: var(--shadow-glow), 0 20px 50px rgba(0, 0, 0, 0.7);
  transform: scale(1.03);
}

.pricing-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--flame-gradient-hot);
  color: #0b0a09;
  font-weight: 800;
  font-size: 0.8rem;
  padding: 4px 18px;
  border-radius: var(--radius-full);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  box-shadow: 0 4px 15px rgba(255, 69, 0, 0.45);
}

.pricing-header {
  margin-bottom: 26px;
}

.plan-name {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.plan-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.pricing-price {
  margin-bottom: 30px;
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.price-currency {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--flame-primary);
}

.price-amount {
  font-size: 3rem;
  font-weight: 900;
  font-family: var(--font-mono);
  color: var(--text-main);
  line-height: 1;
}

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

.pricing-features {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 34px;
  flex-grow: 1;
}

.feature-check {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  font-size: 0.95rem;
  color: var(--text-muted);
}

.check-icon {
  color: var(--flame-primary);
  font-weight: bold;
  flex-shrink: 0;
  margin-top: 2px;
}

/* Articles / Technical Showcase Section */
.articles-section {
  padding: 90px 0;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.article-card {
  background: var(--bg-card);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-card);
}

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

.article-visual {
  height: 200px;
  background: linear-gradient(135deg, rgba(255, 107, 53, 0.15) 0%, rgba(18, 16, 14, 0.8) 100%);
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  border-bottom: 1px solid var(--border-glass);
  overflow: hidden;
}

.article-visual-pattern {
  position: absolute;
  inset: 0;
  background-image: 
    radial-gradient(rgba(255, 107, 53, 0.25) 1px, transparent 1px);
  background-size: 16px 16px;
  opacity: 0.4;
}

.article-tag {
  position: absolute;
  top: 16px;
  left: 16px;
  background: rgba(11, 10, 9, 0.8);
  border: 1px solid var(--border-glass);
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 0.78rem;
  font-family: var(--font-mono);
  color: var(--flame-secondary);
}

.article-badge-icon {
  font-size: 3.2rem;
  color: var(--flame-primary);
  filter: drop-shadow(0 0 15px rgba(255, 107, 53, 0.5));
}

.article-content {
  padding: 30px;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 0.82rem;
  color: var(--text-sub);
  margin-bottom: 12px;
  font-family: var(--font-mono);
}

.article-title {
  font-size: 1.35rem;
  font-weight: 700;
  line-height: 1.45;
  margin-bottom: 14px;
  color: var(--text-main);
  transition: var(--transition);
}

.article-card:hover .article-title {
  color: var(--flame-secondary);
}

.article-summary {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 24px;
  flex-grow: 1;
}

.article-readmore {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--flame-primary);
  margin-top: auto;
}

.article-readmore:hover {
  gap: 12px;
  color: var(--flame-secondary);
}

/* Reviews Section */
.reviews-section {
  padding: 90px 0;
  background: linear-gradient(180deg, transparent, rgba(22, 19, 17, 0.4) 50%, transparent);
}

.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.review-card {
  background: var(--bg-card);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  box-shadow: var(--shadow-card);
  transition: var(--transition);
}

.review-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-glass-bright);
}

.review-stars {
  color: #ff9f1c;
  font-size: 1.1rem;
  margin-bottom: 16px;
  letter-spacing: 2px;
}

.review-text {
  font-size: 0.96rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 22px;
  font-style: italic;
}

.review-user {
  display: flex;
  align-items: center;
  gap: 14px;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  padding-top: 16px;
}

.user-avatar {
  width: 44px;
  height: 44px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-glass);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  color: var(--flame-primary);
  font-family: var(--font-mono);
}

.user-info h4 {
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--text-main);
}

.user-info p {
  font-size: 0.82rem;
  color: var(--text-sub);
}

/* FAQ Accordion Section */
.faq-section {
  padding: 90px 0;
}

.faq-container {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--bg-card);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}

.faq-item:hover {
  border-color: var(--border-glass-bright);
}

.faq-summary {
  padding: 22px 28px;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  list-style: none;
  user-select: none;
  color: var(--text-main);
  transition: var(--transition);
}

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

.faq-icon {
  font-size: 1.25rem;
  color: var(--flame-primary);
  transition: transform 0.3s ease;
}

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

details[open] .faq-summary {
  color: var(--flame-secondary);
  border-bottom: 1px solid rgba(255, 107, 53, 0.12);
}

.faq-body {
  padding: 22px 28px;
  font-size: 0.98rem;
  color: var(--text-muted);
  line-height: 1.75;
}

/* Call to Action Banner */
.cta-banner-section {
  padding: 70px 0 100px;
}

.cta-banner {
  background: radial-gradient(circle at 50% 50%, rgba(255, 107, 53, 0.15) 0%, rgba(18, 16, 14, 0.95) 100%);
  border: 1px solid var(--border-glass-bright);
  border-radius: var(--radius-lg);
  padding: 60px 40px;
  text-align: center;
  box-shadow: var(--shadow-glow), var(--shadow-card);
  position: relative;
  overflow: hidden;
}

.cta-banner-title {
  font-size: 2.4rem;
  font-weight: 800;
  margin-bottom: 16px;
}

.cta-banner-desc {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 680px;
  margin: 0 auto 36px;
}

/* Footer Section */
.site-footer {
  background: #070605;
  border-top: 1px solid rgba(255, 107, 53, 0.12);
  padding: 70px 0 35px;
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 40px;
  margin-bottom: 50px;
}

.footer-col h4 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 20px;
}

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

.footer-col a {
  font-size: 0.92rem;
  color: var(--text-muted);
}

.footer-col a:hover {
  color: var(--flame-secondary);
  padding-left: 4px;
}

.footer-about p {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-top: 14px;
  max-width: 320px;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  padding-top: 30px;
  font-size: 0.85rem;
  color: var(--text-sub);
  flex-wrap: wrap;
  gap: 16px;
}

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

.footer-seo-links a {
  color: var(--text-sub);
}

.footer-seo-links a:hover {
  color: var(--flame-primary);
}

/* Responsive Media Queries */
@media (max-width: 1024px) {
  .features-grid,
  .pricing-grid,
  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .pricing-card.popular {
    transform: none;
  }
  
  .footer-top {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .hero-title {
    font-size: 2.6rem;
  }
  
  .hero-subtitle {
    font-size: 1.05rem;
  }
  
  .features-grid,
  .pricing-grid,
  .articles-grid,
  .reviews-grid {
    grid-template-columns: 1fr;
  }
  
  .nav-menu {
    display: none;
  }
  
  .hero-status-bar {
    flex-direction: column;
    gap: 8px;
    border-radius: var(--radius-md);
  }
  
  .footer-top {
    grid-template-columns: 1fr;
    gap: 30px;
  }
  
  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}