/* ==========================================================================
   一分机场 (yifenjic.sbs) - Thermal Paper Receipt & Micro-Billing Theme
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Courier+Prime:ital,wght@0,400;0,700;1,400&family=Inter:wght@300;400;500;600;700;800&family=Noto+Sans+SC:wght@300;400;500;700;900&display=swap');

:root {
  /* Color Palette */
  --bg-paper: #EDEBE3;
  --bg-paper-dark: #E4E1D7;
  --receipt-white: #FFFFFF;
  --receipt-offwhite: #FAFAFA;
  
  --ink-primary: #1A1A1E;
  --ink-secondary: #4A4A52;
  --ink-muted: #7E7E8A;
  --ink-border: #D8D6CC;

  --stamp-red: #D92B2B;
  --stamp-red-bg: rgba(217, 43, 43, 0.08);
  --stamp-red-glow: rgba(217, 43, 43, 0.25);

  --brand-green: #00A86B;
  --brand-green-hover: #008F5B;
  --brand-green-light: #E6F6F0;
  --brand-green-border: #00A86B;

  --accent-orange: #FF7A00;
  --accent-orange-dark: #E06000;

  /* Typography */
  --font-sans: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: 'Courier Prime', SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace;

  /* Shadows */
  --shadow-receipt: 0 12px 32px rgba(0, 0, 0, 0.08), 0 2px 6px rgba(0, 0, 0, 0.04);
  --shadow-hover: 0 20px 40px rgba(0, 0, 0, 0.12), 0 4px 12px rgba(0, 0, 0, 0.06);
  --shadow-stamp: 0 4px 12px rgba(217, 43, 43, 0.15);

  /* Transitions */
  --tr-fast: 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  --tr-smooth: 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-paper);
}

body {
  font-family: var(--font-sans);
  color: var(--ink-primary);
  background-color: var(--bg-paper);
  background-image: 
    radial-gradient(rgba(0, 0, 0, 0.03) 1px, transparent 0),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.6), rgba(237, 235, 227, 0.8));
  background-size: 24px 24px, 100% 100%;
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

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

/* Layout Utilities */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.narrow-container {
  max-width: 900px;
  margin: 0 auto;
}

/* Receipt Sawtooth Clip-Path Edge */
.receipt-card {
  background: var(--receipt-white);
  border-radius: 4px 4px 0 0;
  box-shadow: var(--shadow-receipt);
  position: relative;
  border: 1px solid rgba(0, 0, 0, 0.05);
  border-bottom: none;
  transition: transform var(--tr-smooth), box-shadow var(--tr-smooth);
}

.receipt-card::after {
  content: '';
  display: block;
  width: 100%;
  height: 16px;
  background: radial-gradient(circle, transparent, transparent 50%, var(--receipt-white) 50%, var(--receipt-white) 100%);
  background-size: 16px 32px;
  background-position: center bottom;
  position: absolute;
  bottom: -16px;
  left: 0;
}

.receipt-sawtooth-bottom {
  position: relative;
  margin-bottom: 24px;
}

.receipt-sawtooth-bottom::after {
  content: "";
  position: absolute;
  bottom: -12px;
  left: 0;
  width: 100%;
  height: 12px;
  background-image: linear-gradient(135deg, var(--receipt-white) 50%, transparent 50%),
                    linear-gradient(225deg, var(--receipt-white) 50%, transparent 50%);
  background-position: top left;
  background-size: 16px 12px;
  background-repeat: repeat-x;
}

/* Thermal Paper Header & Logo */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(237, 235, 227, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px dashed var(--ink-border);
  padding: 16px 0;
}

.nav-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.35rem;
  color: var(--ink-primary);
  letter-spacing: -0.5px;
}

.brand-badge {
  background: var(--stamp-red);
  color: #fff;
  font-size: 0.72rem;
  padding: 2px 8px;
  border-radius: 2px;
  font-weight: 700;
  font-family: var(--font-mono);
  letter-spacing: 1px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
  font-size: 0.95rem;
  font-weight: 500;
}

.nav-links a {
  color: var(--ink-secondary);
  transition: color var(--tr-fast);
  position: relative;
  padding: 4px 0;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--ink-primary);
}

.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--stamp-red);
}

.cta-button {
  background: var(--brand-green);
  color: #ffffff;
  padding: 10px 22px;
  border-radius: 50px;
  font-weight: 700;
  font-size: 0.95rem;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  box-shadow: 0 4px 14px rgba(0, 168, 107, 0.3);
  transition: all var(--tr-fast);
  border: none;
  cursor: pointer;
}

.cta-button:hover {
  background: var(--brand-green-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 168, 107, 0.4);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--ink-primary);
}

/* Red Rubber Stamps */
.stamp {
  display: inline-block;
  font-family: var(--font-mono);
  font-weight: 900;
  text-transform: uppercase;
  color: var(--stamp-red);
  border: 3px double var(--stamp-red);
  padding: 6px 16px;
  border-radius: 4px;
  letter-spacing: 2px;
  transform: rotate(-4deg);
  background: var(--stamp-red-bg);
  box-shadow: var(--shadow-stamp);
  user-select: none;
  animation: stampPop 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.stamp-lg {
  font-size: 1.75rem;
  padding: 10px 24px;
  border-width: 4px;
  transform: rotate(-6deg);
}

.stamp-sm {
  font-size: 0.85rem;
  padding: 3px 10px;
  border-width: 2px;
  transform: rotate(-2deg);
}

@keyframes stampPop {
  0% { opacity: 0; transform: scale(1.6) rotate(-15deg); }
  100% { opacity: 1; transform: scale(1) rotate(-4deg); }
}

/* Monospace Receipt Lines & Dividers */
.receipt-header-meta {
  font-family: var(--font-mono);
  color: var(--ink-muted);
  font-size: 0.85rem;
  border-bottom: 2px dashed var(--ink-border);
  padding-bottom: 12px;
  margin-bottom: 20px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.receipt-divider {
  border-bottom: 2px dashed var(--ink-border);
  margin: 24px 0;
  position: relative;
}

.receipt-divider-dots {
  border-bottom: 1px dotted var(--ink-muted);
  margin: 16px 0;
}

.dot-leader {
  flex-grow: 1;
  border-bottom: 1px dotted var(--ink-border);
  margin: 0 10px;
  position: relative;
  top: -4px;
}

.receipt-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  margin-bottom: 8px;
}

.receipt-row-title {
  font-weight: 700;
  color: var(--ink-primary);
}

.receipt-row-value {
  font-weight: 700;
  color: var(--ink-primary);
}

/* Barcode Element */
.barcode-container {
  text-align: center;
  padding: 20px 0 10px 0;
  font-family: var(--font-mono);
}

.barcode-bars {
  height: 48px;
  width: 260px;
  margin: 0 auto 8px auto;
  background-image: repeating-linear-gradient(
    90deg,
    #111 0px, #111 2px,
    transparent 2px, transparent 4px,
    #111 4px, #111 7px,
    transparent 7px, transparent 9px,
    #111 9px, #111 10px,
    transparent 10px, transparent 14px,
    #111 14px, #111 18px,
    transparent 18px, transparent 20px,
    #111 20px, #111 22px
  );
}

.barcode-text {
  font-size: 0.8rem;
  letter-spacing: 4px;
  color: var(--ink-muted);
}

/* Hero Section */
.hero-section {
  padding: 60px 0 40px 0;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
}

.hero-text-side h1 {
  font-size: 2.75rem;
  font-weight: 900;
  line-height: 1.2;
  margin-bottom: 20px;
  letter-spacing: -1px;
}

.hero-text-side h1 span.highlight {
  color: var(--stamp-red);
  background: linear-gradient(180deg, transparent 70%, rgba(217, 43, 43, 0.15) 70%);
}

.hero-description {
  font-size: 1.15rem;
  color: var(--ink-secondary);
  margin-bottom: 32px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 32px;
}

.secondary-button {
  background: var(--receipt-white);
  color: var(--ink-primary);
  border: 2px solid var(--ink-border);
  padding: 10px 22px;
  border-radius: 50px;
  font-weight: 700;
  font-size: 0.95rem;
  transition: all var(--tr-fast);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.secondary-button:hover {
  border-color: var(--ink-primary);
  background: var(--receipt-offwhite);
}

.hero-badges {
  display: flex;
  align-items: center;
  gap: 20px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--ink-muted);
}

.badge-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.badge-dot {
  width: 8px;
  height: 8px;
  background: var(--brand-green);
  border-radius: 50%;
  display: inline-block;
  box-shadow: 0 0 8px var(--brand-green);
}

.hero-receipt-wrapper {
  padding: 30px;
}

/* Pricing Section - Match User Reference Image */
.pricing-section {
  padding: 80px 0;
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 50px auto;
}

.section-tag {
  font-family: var(--font-mono);
  color: var(--stamp-red);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin-bottom: 8px;
  display: block;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 900;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}

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

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

.price-card {
  background: #FFFFFF;
  border: 2px solid var(--brand-green);
  border-radius: 20px;
  padding: 36px 28px 32px 28px;
  position: relative;
  display: flex;
  flex-direction: column;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.05);
  transition: transform var(--tr-smooth), box-shadow var(--tr-smooth);
}

.price-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 40px rgba(0, 168, 107, 0.12);
}

.price-card.popular {
  border-width: 3px;
  box-shadow: 0 15px 35px rgba(0, 168, 107, 0.15);
}

.popular-badge {
  position: absolute;
  top: -16px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(135deg, #FF7A00, #FF5500);
  color: #FFFFFF;
  font-size: 0.82rem;
  font-weight: 800;
  padding: 4px 18px;
  border-radius: 20px;
  white-space: nowrap;
  box-shadow: 0 4px 12px rgba(255, 85, 0, 0.35);
  letter-spacing: 0.5px;
}

.plan-suitability {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--brand-green);
  margin-bottom: 12px;
}

.plan-data-limit {
  font-size: 2.75rem;
  font-weight: 900;
  color: #1C2421;
  line-height: 1;
  margin-bottom: 12px;
  font-family: var(--font-sans);
}

.plan-price-row {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-bottom: 8px;
}

.plan-price-num {
  font-size: 3rem;
  font-weight: 900;
  color: var(--brand-green);
  line-height: 1;
}

.plan-price-unit {
  font-size: 0.95rem;
  color: var(--ink-secondary);
  font-weight: 500;
}

.plan-billing-breakdown {
  font-size: 0.85rem;
  color: var(--ink-muted);
  margin-bottom: 24px;
  padding-bottom: 20px;
  border-bottom: 1px solid #EAEAEA;
}

.plan-features {
  list-style: none;
  margin-bottom: 32px;
  flex-grow: 1;
}

.plan-features li {
  font-size: 0.95rem;
  color: #2D3A34;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 500;
}

.plan-features li .check-icon {
  color: var(--brand-green);
  font-weight: 900;
}

.btn-green-filled {
  background: var(--brand-green);
  color: #FFFFFF;
  border: none;
  padding: 14px;
  border-radius: 30px;
  font-size: 1rem;
  font-weight: 700;
  text-align: center;
  display: block;
  width: 100%;
  cursor: pointer;
  transition: all var(--tr-fast);
  box-shadow: 0 4px 12px rgba(0, 168, 107, 0.25);
}

.btn-green-filled:hover {
  background: var(--brand-green-hover);
  box-shadow: 0 6px 18px rgba(0, 168, 107, 0.4);
  transform: translateY(-2px);
}

.btn-green-outline {
  background: transparent;
  color: var(--brand-green);
  border: 2px solid var(--brand-green);
  padding: 14px;
  border-radius: 30px;
  font-size: 1rem;
  font-weight: 700;
  text-align: center;
  display: block;
  width: 100%;
  cursor: pointer;
  transition: all var(--tr-fast);
}

.btn-green-outline:hover {
  background: var(--brand-green-light);
  transform: translateY(-2px);
}

/* Features Grid */
.features-section {
  padding: 70px 0;
}

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

.feature-card {
  padding: 32px 24px;
}

.feature-icon {
  width: 52px;
  height: 52px;
  background: var(--brand-green-light);
  color: var(--brand-green);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 20px;
  font-weight: bold;
}

.feature-card h3 {
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--ink-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Target Audience Section */
.audience-section {
  padding: 70px 0;
}

.audience-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.audience-card {
  text-align: center;
  padding: 28px 20px;
}

.audience-avatar {
  font-size: 2.5rem;
  margin-bottom: 14px;
}

.audience-card h4 {
  font-size: 1.1rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.audience-card p {
  font-size: 0.88rem;
  color: var(--ink-secondary);
}

/* Tutorial Quick Guide Section */
.tutorial-preview-section {
  padding: 70px 0;
}

.tutorial-steps-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-top: 30px;
}

.step-card {
  position: relative;
  padding: 28px 20px;
}

.step-number {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 900;
  color: var(--stamp-red);
  margin-bottom: 12px;
}

.step-card h4 {
  font-size: 1.1rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.step-card p {
  font-size: 0.9rem;
  color: var(--ink-secondary);
  line-height: 1.5;
}

/* Testimonials / Reviews Section */
.testimonials-section {
  padding: 70px 0;
}

.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.testimonial-card {
  padding: 28px 24px;
}

.testimonial-stars {
  color: #FFB800;
  font-size: 1.1rem;
  margin-bottom: 12px;
}

.testimonial-text {
  font-size: 0.95rem;
  color: var(--ink-primary);
  line-height: 1.6;
  margin-bottom: 20px;
  font-style: italic;
}

.testimonial-user {
  display: flex;
  align-items: center;
  gap: 12px;
}

.user-avatar-text {
  width: 40px;
  height: 40px;
  background: var(--ink-primary);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-family: var(--font-mono);
}

.user-info h5 {
  font-size: 0.95rem;
  font-weight: 700;
}

.user-info span {
  font-size: 0.8rem;
  color: var(--ink-muted);
}

/* Accordion FAQ Component */
.faq-section {
  padding: 70px 0;
}

.faq-accordion {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--receipt-white);
  border: 1px solid var(--ink-border);
  border-radius: 8px;
  overflow: hidden;
}

.faq-question {
  padding: 20px 24px;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--ink-primary);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  user-select: none;
}

.faq-toggle {
  font-size: 1.2rem;
  font-family: var(--font-mono);
  transition: transform var(--tr-fast);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  padding: 0 24px;
  color: var(--ink-secondary);
  font-size: 0.98rem;
  line-height: 1.7;
}

.faq-item.open .faq-answer {
  max-height: 500px;
  padding: 0 24px 20px 24px;
}

.faq-item.open .faq-toggle {
  transform: rotate(45deg);
  color: var(--stamp-red);
}

/* Articles Directory Preview Grid */
.articles-preview-section {
  padding: 70px 0;
}

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

.article-card {
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.article-tag {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--brand-green);
  font-weight: 700;
  text-transform: uppercase;
  margin-bottom: 10px;
  display: inline-block;
}

.article-card h3 {
  font-size: 1.15rem;
  font-weight: 800;
  margin-bottom: 12px;
  line-height: 1.4;
}

.article-card h3 a:hover {
  color: var(--brand-green);
}

.article-card p {
  font-size: 0.9rem;
  color: var(--ink-secondary);
  margin-bottom: 20px;
  line-height: 1.6;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--ink-muted);
  border-top: 1px dashed var(--ink-border);
  padding-top: 14px;
}

/* Article Detail Content Layout */
.article-detail-header {
  padding: 40px 0 20px 0;
  text-align: center;
}

.breadcrumb {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--ink-muted);
  margin-bottom: 16px;
}

.breadcrumb a:hover {
  color: var(--stamp-red);
}

.article-detail-header h1 {
  font-size: 2.25rem;
  font-weight: 900;
  line-height: 1.3;
  margin-bottom: 16px;
}

.article-detail-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--ink-muted);
}

.article-body {
  padding: 40px 32px;
  font-size: 1.05rem;
  line-height: 1.85;
  color: #2D2D32;
}

.article-body h2 {
  font-size: 1.6rem;
  font-weight: 800;
  margin: 36px 0 16px 0;
  padding-bottom: 8px;
  border-bottom: 2px dashed var(--ink-border);
}

.article-body h3 {
  font-size: 1.28rem;
  font-weight: 700;
  margin: 28px 0 12px 0;
  color: var(--brand-green);
}

.article-body p {
  margin-bottom: 20px;
}

.article-body ul, .article-body ol {
  margin: 0 0 24px 24px;
}

.article-body li {
  margin-bottom: 8px;
}

.article-body blockquote {
  background: var(--brand-green-light);
  border-left: 4px solid var(--brand-green);
  padding: 16px 20px;
  margin: 24px 0;
  border-radius: 0 8px 8px 0;
  font-style: italic;
}

.article-body code {
  font-family: var(--font-mono);
  background: #F0EEE6;
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.9em;
  color: var(--stamp-red);
}

/* Page Footer */
.site-footer {
  background: #1A1A1E;
  color: #ECEAE1;
  padding: 60px 0 30px 0;
  margin-top: 80px;
  font-size: 0.92rem;
}

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

.footer-brand h4 {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  color: #FFFFFF;
  margin-bottom: 12px;
}

.footer-brand p {
  color: #A0A0AA;
  line-height: 1.6;
  margin-bottom: 20px;
}

.footer-links-col h5 {
  font-family: var(--font-mono);
  color: #FFFFFF;
  font-size: 1rem;
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

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

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

.footer-links-col a {
  color: #A0A0AA;
  transition: color var(--tr-fast);
}

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

.footer-keywords-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.keyword-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  background: #2A2A30;
  color: #C0C0CB;
  padding: 4px 10px;
  border-radius: 4px;
}

.footer-bottom {
  border-top: 1px solid #2D2D35;
  padding-top: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  color: #80808C;
  font-family: var(--font-mono);
  font-size: 0.82rem;
}

/* Responsive Styles */
@media (max-width: 992px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }
  .pricing-grid {
    grid-template-columns: 1fr;
    max-width: 500px;
    margin: 0 auto;
  }
  .features-grid, .testimonials-grid, .articles-grid {
    grid-template-columns: 1fr 1fr;
  }
  .audience-grid, .tutorial-steps-grid {
    grid-template-columns: 1fr 1fr;
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 640px) {
  .nav-links {
    display: none;
  }
  .mobile-menu-btn {
    display: block;
  }
  .features-grid, .testimonials-grid, .articles-grid, .audience-grid, .tutorial-steps-grid {
    grid-template-columns: 1fr;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .hero-text-side h1 {
    font-size: 2rem;
  }
  .stamp-lg {
    font-size: 1.3rem;
  }
}