/* ==========================================================================
   好鸭云 Nice Duck Official Stylesheet
   Theme: Modern White / Glassmorphism / Duck Elements
   ========================================================================== */

/* Google Fonts - Inter & Outfit */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&display=swap');

:root {
  /* Color Palette - Premium White & Soft Grey */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #f1f3f5;
  --card-bg: rgba(255, 255, 255, 0.85);
  --card-border: rgba(230, 235, 240, 0.8);
  
  /* Text Colors */
  --text-primary: #1a1e21;
  --text-secondary: #495057;
  --text-muted: #868e96;
  
  /* Accents - Nice Duck Theme (Yellow/Orange) */
  --duck-yellow: #ffd000;
  --duck-yellow-hover: #ffc000;
  --duck-orange: #ff8c00;
  --duck-shadow: rgba(255, 208, 0, 0.3);
  --accent-blue: #0076ff; /* For security/trust highlights */

  /* Font Families */
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-heading: 'Outfit', var(--font-body);
  
  /* Layout */
  --max-width: 1200px;
  --border-radius-sm: 8px;
  --border-radius-md: 16px;
  --border-radius-lg: 24px;
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
}

/* CSS Reset & Base Styles */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  background-image: linear-gradient(rgba(255, 255, 255, 0.94), rgba(255, 255, 255, 0.94)), url('../images/duck_bg.jpg');
  background-size: 360px 360px;
  background-repeat: repeat;
  background-attachment: fixed;
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.25;
}

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

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

/* Text Gradient Effect (White-to-Black Style)
   To maintain legibility on a white background, we use a sleek gradient from light charcoal-grey to deep solid black. */
.text-gradient {
  background: linear-gradient(180deg, #7c8893 0%, #111518 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  color: var(--text-primary); /* Fallback */
  display: inline-block;
}

/* Header & Navigation */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--card-border);
  transition: var(--transition-normal);
}

.header.scrolled {
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.04);
  background: rgba(255, 255, 255, 0.9);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.25rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.5rem;
  font-weight: 800;
  font-family: var(--font-heading);
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--duck-orange) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.logo img {
  width: 32px;
  height: 32px;
  object-fit: contain;
  filter: drop-shadow(0 2px 4px rgba(255,208,0,0.4));
}

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

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

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

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--text-primary);
  margin: 5px 0;
  transition: var(--transition-fast);
}

/* ==========================================================================
   BUTTON STYLE: DUCK BUTTON (按钮变鸭子)
   A premium custom styled button that shapes into a duck and wiggles on hover.
   ========================================================================== */
.duck-btn {
  display: inline-flex;
  align-items: center;
  position: relative;
  cursor: pointer;
  padding: 0.75rem 2.2rem;
  background-color: var(--duck-yellow);
  border: 2px solid var(--text-primary);
  border-radius: 40px 50px 30px 40px; /* Custom organic duck shape */
  box-shadow: 4px 4px 0px var(--text-primary), 0 8px 20px var(--duck-shadow);
  color: var(--text-primary) !important;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.05rem;
  transition: all 0.25s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  user-select: none;
  z-index: 10;
}

/* Duck Beak (嘴巴) */
.duck-btn::after {
  content: '';
  position: absolute;
  right: -10px;
  top: 50%;
  transform: translateY(-50%);
  width: 14px;
  height: 12px;
  background-color: var(--duck-orange);
  border: 2px solid var(--text-primary);
  border-radius: 0 50% 50% 0;
  transition: var(--transition-fast);
  transform-origin: left center;
}

/* Duck Tail (屁股/尾巴) */
.duck-btn::before {
  content: '';
  position: absolute;
  left: -6px;
  top: 35%;
  width: 10px;
  height: 15px;
  background-color: var(--duck-yellow);
  border-left: 2px solid var(--text-primary);
  border-top: 2px solid var(--text-primary);
  border-radius: 50% 0 0 50%;
  transform: rotate(-15deg);
  transition: var(--transition-fast);
}

/* Wing Icon / Indicator (翅膀) */
.duck-wing {
  display: inline-block;
  width: 16px;
  height: 12px;
  background-color: rgba(0, 0, 0, 0.1);
  border: 1.5px solid var(--text-primary);
  border-radius: 50% 50% 50% 50%;
  margin-right: 8px;
  position: relative;
  transition: var(--transition-fast);
  transform-origin: left bottom;
}

/* Eye element (眼睛) */
.duck-eye {
  position: absolute;
  right: 12px;
  top: 10px;
  width: 4px;
  height: 4px;
  background-color: var(--text-primary);
  border-radius: 50%;
}

.duck-btn:hover {
  transform: translateY(-3px) scale(1.03);
  background-color: var(--duck-yellow-hover);
  box-shadow: 6px 6px 0px var(--text-primary), 0 12px 25px var(--duck-shadow);
  animation: duckWobble 0.6s ease-in-out infinite alternate;
}

.duck-btn:hover .duck-wing {
  animation: wingFlap 0.3s ease-in-out infinite alternate;
}

.duck-btn:hover::after {
  transform: translateY(-50%) rotate(15deg) scale(1.1);
}

.duck-btn:active {
  transform: translateY(2px) scale(0.98);
  box-shadow: 2px 2px 0px var(--text-primary), 0 4px 10px var(--duck-shadow);
}

/* Duck Animations */
@keyframes duckWobble {
  0% { transform: translateY(-3px) rotate(-1.5deg); }
  100% { transform: translateY(-3px) rotate(1.5deg); }
}

@keyframes wingFlap {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(-35deg); }
}

/* Duck Button Small Version (for pricing/cards) */
.duck-btn-sm {
  font-size: 0.95rem;
  padding: 0.6rem 1.6rem;
  border-radius: 30px 40px 24px 30px;
}
.duck-btn-sm::after {
  width: 10px;
  height: 9px;
  right: -8px;
}
.duck-btn-sm::before {
  width: 8px;
  height: 12px;
  left: -5px;
}

/* ==========================================================================
   HOMEPAGE DUCK BACKGROUND ELEMENTS (鸭子背景元素)
   Floating cute duck shapes behind content with low opacity.
   ========================================================================== */
.duck-bg-container {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  pointer-events: none;
  z-index: 1;
}

.duck-bg-element {
  position: absolute;
  opacity: 0.04; /* Very subtle white-themed background */
  fill: var(--text-primary);
  animation: floatBackground 20s infinite linear;
}

.duck-bg-element.yellow {
  opacity: 0.07;
  fill: var(--duck-yellow);
}

.duck-bg-1 {
  top: 15%;
  left: 5%;
  width: 120px;
  animation-duration: 25s;
}

.duck-bg-2 {
  top: 30%;
  right: 8%;
  width: 160px;
  animation-duration: 35s;
  animation-delay: -5s;
}

.duck-bg-3 {
  bottom: 25%;
  left: 8%;
  width: 140px;
  animation-duration: 30s;
  animation-delay: -12s;
}

.duck-bg-4 {
  bottom: 8%;
  right: 15%;
  width: 100px;
  animation-duration: 22s;
  animation-delay: -3s;
}

@keyframes floatBackground {
  0% {
    transform: translateY(0) rotate(0deg) translateX(0);
  }
  33% {
    transform: translateY(-15px) rotate(5deg) translateX(10px);
  }
  66% {
    transform: translateY(10px) rotate(-5deg) translateX(-15px);
  }
  100% {
    transform: translateY(0) rotate(0deg) translateX(0);
  }
}

/* ==========================================================================
   SECTIONS LAYOUT
   ========================================================================== */

/* Hero Section */
.hero {
  position: relative;
  padding: 10rem 2rem 6rem;
  background: radial-gradient(circle at 80% 20%, rgba(255, 208, 0, 0.05) 0%, rgba(255, 255, 255, 0) 50%), var(--bg-primary);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  min-height: 85vh;
  justify-content: center;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--card-border);
  border-radius: 50px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.hero-tag span {
  width: 8px;
  height: 8px;
  background-color: var(--duck-orange);
  border-radius: 50%;
  display: inline-block;
  animation: pulse 1.5s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.9); opacity: 0.6; }
  50% { transform: scale(1.2); opacity: 1; }
  100% { transform: scale(0.9); opacity: 0.6; }
}

.hero h1 {
  font-size: 3.8rem;
  letter-spacing: -0.03em;
  max-width: 900px;
  margin-bottom: 1.5rem;
}

.hero p {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 650px;
  margin-bottom: 3rem;
  font-weight: 400;
}

.hero-actions {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 3rem;
  margin-top: 6rem;
  max-width: 800px;
  width: 100%;
}

.stat-item h3 {
  font-size: 2rem;
  color: var(--text-primary);
}

.stat-item p {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin: 0;
}

/* Feature Section */
.section {
  position: relative;
  padding: 6rem 2rem;
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-header {
  text-align: center;
  max-width: 600px;
  margin: 0 auto 4rem;
}

.section-header h2 {
  font-size: 2.25rem;
  margin-bottom: 1rem;
}

.section-header p {
  color: var(--text-secondary);
  font-size: 1.05rem;
}

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.feature-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  padding: 2.5rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.015);
  transition: var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.03);
  border-color: rgba(255, 208, 0, 0.4);
}

.feature-icon {
  width: 50px;
  height: 50px;
  background-color: var(--bg-secondary);
  border-radius: var(--border-radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
  border: 1px solid var(--card-border);
  transition: var(--transition-normal);
}

.feature-card:hover .feature-icon {
  background-color: var(--duck-yellow);
  border-color: var(--text-primary);
}

.feature-icon svg {
  width: 24px;
  height: 24px;
  fill: var(--text-primary);
}

.feature-card h3 {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* ==========================================================================
   PRICING CARD STYLING (白色卡片与黄色鸭子按钮)
   ========================================================================== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  align-items: stretch;
  margin-top: 1rem;
}

.pricing-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-lg);
  padding: 3rem 2.5rem;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition-normal);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.01);
}

.pricing-card.popular {
  border: 2px solid var(--text-primary);
  box-shadow: 0 20px 40px rgba(255, 208, 0, 0.1);
  transform: scale(1.03);
}

.pricing-card.popular::before {
  content: '推荐';
  position: absolute;
  top: 1.25rem;
  right: 1.25rem;
  background: var(--duck-yellow);
  border: 1.5px solid var(--text-primary);
  color: var(--text-primary);
  font-weight: 800;
  font-size: 0.75rem;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
}

.pricing-header h3 {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.pricing-header p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 1.5rem;
}

.pricing-price {
  margin-bottom: 2rem;
  display: flex;
  align-items: baseline;
}

.pricing-price .currency {
  font-size: 1.5rem;
  font-weight: 700;
}

.pricing-price .amount {
  font-size: 3.5rem;
  font-weight: 800;
  font-family: var(--font-heading);
  line-height: 1;
}

.pricing-price .period {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-left: 0.25rem;
}

.pricing-features {
  list-style: none;
  margin-bottom: 3rem;
  flex-grow: 1;
}

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.pricing-features li svg {
  width: 18px;
  height: 18px;
  fill: var(--duck-orange);
  flex-shrink: 0;
}

.pricing-card .duck-btn {
  width: 100%;
  justify-content: center;
}

/* ==========================================================================
   USER REVIEWS / TESTIMONIALS (用户评价)
   ========================================================================== */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.review-card {
  background: var(--bg-secondary);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  padding: 2rem;
  position: relative;
}

.review-stars {
  display: flex;
  gap: 0.25rem;
  margin-bottom: 1rem;
}

.review-stars svg {
  width: 16px;
  height: 16px;
  fill: var(--duck-yellow);
}

.review-text {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
  font-style: italic;
}

.review-user {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.review-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--duck-yellow);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  color: var(--text-primary);
  font-size: 0.9rem;
  border: 1.5px solid var(--text-primary);
}

.review-info h4 {
  font-size: 0.95rem;
  margin: 0;
}

.review-info p {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin: 0;
}

/* ==========================================================================
   FAQ SECTION (常见问题)
   ========================================================================== */
.faq-container {
  max-width: 800px;
  margin: 0 auto;
}

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

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

.faq-icon {
  width: 20px;
  height: 20px;
  transition: var(--transition-normal);
  fill: var(--text-secondary);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s cubic-bezier(0, 1, 0, 1);
  padding: 0 1.5rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.faq-item.active {
  border-color: var(--text-primary);
  background: var(--bg-primary);
}

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

.faq-item.active .faq-answer {
  max-height: 500px;
  padding-bottom: 1.5rem;
  transition: max-height 0.5s ease-in-out;
}

/* ==========================================================================
   ARTICLES SECTION (文章网格)
   ========================================================================== */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.article-card {
  background: var(--bg-primary);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  overflow: hidden;
  transition: var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.article-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.03);
  border-color: var(--text-primary);
}

.article-image {
  height: 180px;
  background: var(--bg-secondary);
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.article-image svg {
  width: 60px;
  height: 60px;
  fill: var(--duck-yellow);
  opacity: 0.8;
}

.article-content {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.article-meta {
  display: flex;
  gap: 1rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.article-title {
  font-size: 1.15rem;
  margin-bottom: 0.75rem;
  line-height: 1.4;
}

.article-excerpt {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  flex-grow: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-link {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-primary);
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}

.article-link svg {
  width: 14px;
  height: 14px;
  transition: var(--transition-fast);
}

.article-card:hover .article-link svg {
  transform: translateX(4px);
}

/* =style.css for ARTICLE DETAIL pages */
.article-container {
  max-width: 800px;
  margin: 8rem auto 4rem;
  padding: 0 2rem;
}

.article-header {
  margin-bottom: 3rem;
}

.article-header h1 {
  font-size: 2.75rem;
  margin-bottom: 1rem;
}

.article-body {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.8;
}

.article-body h2 {
  font-size: 1.6rem;
  margin: 2.5rem 0 1rem;
  color: var(--text-primary);
}

.article-body h3 {
  font-size: 1.25rem;
  margin: 1.8rem 0 0.8rem;
  color: var(--text-primary);
}

.article-body p {
  margin-bottom: 1.5rem;
}

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

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

.article-body strong {
  color: var(--text-primary);
}

.article-body blockquote {
  border-left: 4px solid var(--duck-yellow);
  background-color: var(--bg-secondary);
  padding: 1rem 1.5rem;
  margin: 2rem 0;
  font-style: italic;
  border-radius: 0 var(--border-radius-sm) var(--border-radius-sm) 0;
}

.article-footer {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--card-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.article-back {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
}

.article-back svg {
  width: 16px;
  height: 16px;
  transform: rotate(180deg);
}

/* ==========================================================================
   FOOTER
   ========================================================================== */
.footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--card-border);
  padding: 5rem 2rem 3rem;
  position: relative;
  z-index: 2;
}

.footer-container {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 4rem;
}

.footer-brand h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.footer-brand p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 1.5rem;
  max-width: 320px;
}

.footer-heading {
  font-size: 0.95rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 0.75rem;
}

.footer-links a {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.footer-links a:hover {
  color: var(--text-primary);
  padding-left: 4px;
}

.footer-newsletter p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.newsletter-form {
  display: flex;
  gap: 0.5rem;
}

.newsletter-input {
  flex-grow: 1;
  padding: 0.75rem 1rem;
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-sm);
  background-color: var(--bg-primary);
  font-family: inherit;
  font-size: 0.9rem;
  outline: none;
}

.newsletter-input:focus {
  border-color: var(--text-primary);
}

.newsletter-form .duck-btn {
  padding: 0.75rem 1.2rem;
  border-radius: 8px;
}
.newsletter-form .duck-btn::after, .newsletter-form .duck-btn::before {
  display: none; /* simple button */
}

.footer-bottom {
  max-width: var(--max-width);
  margin: 4rem auto 0;
  padding-top: 2rem;
  border-top: 1px solid var(--card-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ==========================================================================
   RESPONSIVE DESIGN (适配移动端)
   ========================================================================== */
@media (max-width: 1024px) {
  .hero h1 {
    font-size: 3rem;
  }
  .pricing-grid, .reviews-grid, .articles-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-card.popular {
    transform: scale(1);
    margin: 0;
  }
  .footer-container {
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    position: fixed;
    top: 73px;
    left: 0;
    width: 100%;
    height: calc(100vh - 73px);
    background-color: var(--bg-primary);
    flex-direction: column;
    padding: 3rem 2rem;
    gap: 2rem;
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all 0.4s cubic-bezier(0.1, 0.9, 0.2, 1);
    border-top: 1px solid var(--card-border);
  }
  
  .nav-menu.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-toggle {
    display: block;
  }

  .nav-toggle.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  
  .nav-toggle.active span:nth-child(2) {
    opacity: 0;
  }
  
  .nav-toggle.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .hero {
    padding: 8rem 1.5rem 4rem;
  }

  .hero h1 {
    font-size: 2.4rem;
  }

  .hero p {
    font-size: 1.1rem;
    margin-bottom: 2rem;
  }

  .hero-actions {
    flex-direction: column;
    width: 100%;
    gap: 1rem;
  }

  .hero-actions .duck-btn, .hero-actions .secondary-btn {
    width: 100%;
    justify-content: center;
  }

  .hero-stats {
    gap: 1.5rem;
    margin-top: 4rem;
  }

  .stat-item h3 {
    font-size: 1.5rem;
  }

  .pricing-grid, .reviews-grid, .articles-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .footer-container {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }

  .article-header h1 {
    font-size: 2rem;
  }
}

/* Secondary Button Style */
.secondary-btn {
  display: inline-flex;
  align-items: center;
  padding: 0.75rem 2rem;
  border-radius: 40px;
  border: 2px solid var(--text-primary);
  font-weight: 700;
  font-size: 1.05rem;
  font-family: var(--font-heading);
  background: transparent;
  color: var(--text-primary);
  transition: var(--transition-fast);
}

.secondary-btn:hover {
  background-color: var(--bg-secondary);
  transform: translateY(-2px);
}