/* ===========================
   Design System & Variables
   =========================== */
:root {
  --color-primary: #ffffff;
  --color-primary-light: #f5f5f5;
  --color-primary-dark: #a3a3a3;
  --color-accent: #ffffff;         /* モノトーンのアクセント */
  --color-accent-light: #e5e5e5;
  --color-bg: #000000;             /* 深い純黒 */
  --color-bg-card: #0a0a0a;
  --color-bg-card-hover: #121212;
  --color-surface: #000000;
  --color-text: #ededed;
  --color-text-muted: #888888;
  --color-border: rgba(255, 255, 255, 0.1);
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --gradient-primary: linear-gradient(135deg, #ffffff 0%, #a3a3a3 100%);
  --gradient-hero: radial-gradient(circle at top, #111111 0%, #000000 100%);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 40px rgba(255, 255, 255, 0.08); /* 繊細な発光 */
  --radius-sm: 6px;
  --radius-md: 8px; /* Linear風に角をわずかにシャープに */
  --radius-lg: 12px;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  scroll-padding-top: 90px;
}

*:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: 4px;
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a:hover {
  color: var(--color-accent-light);
}

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

/* ===========================
   Typography
   =========================== */
h1, h2, h3, h4 {
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(2.2rem, 5vw, 4rem);
  color: #fff;
  letter-spacing: -0.04em;
}

h2 {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  color: #fff;
  letter-spacing: -0.03em;
}

h3 {
  font-size: 1.3rem;
  color: #fff;
  letter-spacing: -0.02em;
}

p {
  color: var(--color-text-muted);
  font-size: 1.05rem;
  line-height: 1.8;
}

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

.section {
  padding: 80px 0;
}

/* ===========================
   Navigation
   =========================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(10, 10, 10, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: var(--transition);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.nav-logo {
  font-size: 1.4rem;
  font-weight: 800;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.03em;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 8px;
}

.nav-links a {
  color: var(--color-text-muted);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 500;
  transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-text);
  background: var(--color-bg-card);
}

.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 8px;
}

.nav-hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: var(--transition);
}

/* ===========================
   Hero Section
   =========================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  background: var(--gradient-hero);
  position: relative;
  overflow: hidden;
  padding-top: 72px;
}

.hero::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(79, 70, 229, 0.15) 0%, transparent 70%);
  border-radius: 50%;
  animation: heroPulse 4s ease-in-out infinite;
}

@keyframes heroPulse {
  0%, 100% { transform: translate(-50%, -50%) scale(1); opacity: 0.5; }
  50% { transform: translate(-50%, -50%) scale(1.2); opacity: 1; }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 700px;
}

.hero-badge {
  display: inline-block;
  padding: 6px 16px;
  background: rgba(79, 70, 229, 0.15);
  border: 1px solid rgba(79, 70, 229, 0.3);
  border-radius: 50px;
  color: var(--color-primary-light);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 24px;
  letter-spacing: 0.05em;
}

.hero h1 {
  margin-bottom: 20px;
}

.hero p {
  font-size: 1.2rem;
  margin-bottom: 36px;
  max-width: 550px;
  margin-left: auto;
  margin-right: auto;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ===========================
   Buttons
   =========================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  text-decoration: none;
}

.btn-primary {
  background: var(--gradient-primary);
  color: white;
  box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(79, 70, 229, 0.5);
  color: white;
}

.btn-secondary {
  background: var(--color-bg-card);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-bg-card-hover);
  border-color: var(--color-primary-light);
  color: var(--color-text);
  transform: translateY(-2px);
}

/* ===========================
   Cards
   =========================== */
.card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px;
  transition: var(--transition);
}

.card:hover {
  border-color: var(--color-primary);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-sm);
  background: var(--gradient-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 20px;
}

.card h3 {
  margin-bottom: 12px;
}

.card p {
  font-size: 0.95rem;
}

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

/* ===========================
   Section Headers
   =========================== */
.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-header h2 {
  margin-bottom: 16px;
}

.section-header p {
  max-width: 600px;
  margin: 0 auto;
}

.section-label {
  display: inline-block;
  color: var(--color-primary-light);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 12px;
}

/* ===========================
   Features Section
   =========================== */
.features-list {
  display: flex;
  flex-direction: column;
  gap: 48px;
}

.feature-item {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.feature-item:nth-child(even) {
  direction: rtl;
}

.feature-item:nth-child(even) > * {
  direction: ltr;
}

.feature-visual {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px;
  aspect-ratio: 16/10;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  position: relative;
  overflow: hidden;
}

.feature-visual::after {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gradient-primary);
  opacity: 0.05;
}

.feature-text h3 {
  font-size: 1.5rem;
  margin-bottom: 16px;
}

.feature-text p {
  margin-bottom: 20px;
}

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

.tag {
  padding: 4px 12px;
  background: rgba(79, 70, 229, 0.1);
  border: 1px solid rgba(79, 70, 229, 0.2);
  border-radius: 50px;
  font-size: 0.8rem;
  color: var(--color-primary-light);
  font-weight: 500;
}

/* ===========================
   Stats Section
   =========================== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  text-align: left;
}

.stat-item {
  padding: 24px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: var(--transition);
}

.stat-item:hover {
  border-color: rgba(255, 255, 255, 0.2);
  background: var(--color-bg-card-hover);
}

.stat-number {
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.stat-label {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-top: 12px;
  font-weight: 500;
}

/* ===========================
   Blog / Article Cards
   =========================== */
.article-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
  position: relative;
}

.article-card::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05);
  pointer-events: none;
}

.article-card:hover {
  border-color: rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.03);
  transform: translateY(-2px);
  box-shadow: 0 10px 40px -10px rgba(0, 0, 0, 0.8), 0 0 20px rgba(255, 255, 255, 0.03);
}

.article-card-image {
  height: 200px;
  background: var(--gradient-primary);
  opacity: 0.8;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
}

.article-card-body {
  padding: 24px;
}

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

.article-meta .category {
  padding: 2px 10px;
  background: rgba(6, 182, 212, 0.1);
  border: 1px solid rgba(6, 182, 212, 0.2);
  border-radius: 50px;
  color: var(--color-accent);
  font-weight: 500;
}

.article-card-body h3 {
  margin-bottom: 12px;
  font-size: 1.25rem;
  line-height: 1.5;
  font-weight: 700;
}

.article-card-body h3 a {
  color: #f1f5f9;
  text-decoration: none;
}

.article-card-body h3 a:hover {
  color: #818cf8;
}

.article-card-body p {
  font-size: 0.95rem;
  line-height: 1.6;
  color: #cbd5e1;
}

.read-more {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 16px;
  font-weight: 600;
  font-size: 0.9rem;
}

/* ===========================
   About Page
   =========================== */
.page-header {
  padding-top: 140px;
  padding-bottom: 60px;
  text-align: center;
  background: var(--gradient-hero);
  position: relative;
}

.page-header::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.1) 0%, transparent 70%);
  border-radius: 50%;
}

.page-header h1 {
  position: relative;
  z-index: 1;
  margin-bottom: 16px;
}

.page-header p {
  position: relative;
  z-index: 1;
  max-width: 600px;
  margin: 0 auto;
  color: #cbd5e1;
  font-size: 1.15rem;
}

.about-content {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 48px;
  align-items: start;
}

.about-text h2 {
  margin-bottom: 20px;
  font-size: 1.75rem;
}

.about-text p {
  margin-bottom: 16px;
}

.about-sidebar .card {
  margin-bottom: 24px;
}

.skill-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.skill-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--color-text-muted);
}

.skill-list li::before {
  content: '✦';
  color: var(--color-primary-light);
  font-size: 0.8rem;
}

.timeline {
  position: relative;
  padding-left: 32px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-border);
}

.timeline-item {
  position: relative;
  margin-bottom: 32px;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -37px;
  top: 6px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 2px solid var(--color-bg);
}

.timeline-item h4 {
  font-size: 1rem;
  color: var(--color-primary-light);
  margin-bottom: 4px;
}

.timeline-item p {
  font-size: 0.9rem;
}

/* ===========================
   Footer
   =========================== */
.footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: 48px 0 24px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer-brand p {
  margin-top: 12px;
  font-size: 0.9rem;
}

.footer-col h4 {
  font-size: 0.9rem;
  color: var(--color-text);
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

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

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

.footer-col ul a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.footer-col ul a:hover {
  color: var(--color-accent-light);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 24px;
  border-top: 1px solid var(--color-border);
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* ===========================
   Animations
   =========================== */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.6s ease forwards;
}

.fade-in:nth-child(2) { animation-delay: 0.1s; }
.fade-in:nth-child(3) { animation-delay: 0.2s; }
.fade-in:nth-child(4) { animation-delay: 0.3s; }

@keyframes fadeInUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.floating {
  animation: float 3s ease-in-out infinite;
}

/* ===========================
   Responsive
   =========================== */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: 16px;
  }

  .nav-links.active {
    display: flex;
  }

  .nav-hamburger {
    display: flex;
  }

  .feature-item {
    grid-template-columns: 1fr;
  }

  .feature-item:nth-child(even) {
    direction: ltr;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .about-content {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 480px) {
  .stats-grid {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }

  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }
}

/* ===========================
   Article Page — Reader-Optimized
   =========================== */

/* Article Container */
.article-container {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 20px 80px;
}

/* Article Header */
.article-header {
  margin-top: 120px;
  margin-bottom: 56px;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--color-border);
}

.article-header h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  color: var(--color-text);
  line-height: 1.3;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  flex-wrap: wrap;
}

.article-meta .category {
  padding: 4px 14px;
  background: rgba(6, 182, 212, 0.1);
  border: 1px solid rgba(6, 182, 212, 0.2);
  border-radius: 50px;
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.8rem;
}

/* Author Info */
.author-info {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: 20px;
}

.author-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--gradient-primary);
  flex-shrink: 0;
}

.author-name {
  display: block;
  font-weight: 600;
  color: var(--color-text);
  font-size: 0.95rem;
}

.author-title {
  display: block;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

/* Article Body — Typography Optimized for Reading */
.article-content {
  font-size: 1.15rem;
  line-height: 1.9;
  color: var(--color-text-muted);
  letter-spacing: 0;
  font-weight: 400;
}

.article-content p {
  margin-bottom: 1.8em;
  color: var(--color-text-muted);
  font-size: inherit;
}

.article-content a {
  color: #67e8f9;
  text-decoration: underline;
  text-decoration-color: rgba(103,232,249,0.3);
  text-underline-offset: 3px;
  transition: all 0.2s ease;
}
.article-content a:hover {
  color: #a5f3fc;
  text-decoration-color: rgba(103,232,249,0.8);
}

/* Headings inside article */
.article-content h2 {
  font-size: 1.8rem;
  color: var(--color-text);
  margin-top: 80px;
  margin-bottom: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.4;
}

.article-content h3 {
  font-size: 1.4rem;
  color: var(--color-text);
  margin-top: 56px;
  margin-bottom: 20px;
  font-weight: 700;
  line-height: 1.4;
}

.article-content h4 {
  font-size: 1.15rem;
  color: var(--color-text);
  margin-top: 32px;
  margin-bottom: 16px;
  font-weight: 600;
}

/* Lists */
.article-content ul,
.article-content ol {
  margin-bottom: 1.8em;
  padding-left: 1.2em;
}

.article-content li {
  margin-bottom: 0.8em;
  color: var(--color-text-muted);
  line-height: 1.8;
}

.article-content li::marker {
  color: #52525b; /* Zinc 600 */
}

/* Code */
.article-content code {
  background: rgba(255, 255, 255, 0.08);
  color: #e4e4e7;
  padding: 3px 6px;
  border-radius: 4px;
  font-size: 0.85em;
  font-family: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05);
}

.article-content pre {
  margin: 32px 0;
  background: #000000;
  border: 1px solid var(--color-border);
  padding: 24px;
  border-radius: var(--radius-md);
  overflow-x: auto;
  font-size: 0.9rem;
  line-height: 1.6;
}

.article-content pre code {
  background: none;
  padding: 0;
  color: var(--color-text-muted);
  font-size: inherit;
  box-shadow: none;
}

/* Blockquote */
.article-content blockquote {
  margin: 32px 0;
  padding: 16px 24px;
  border-left: 2px solid #52525b;
  background: transparent;
  color: #d4d4d8;
  font-style: italic;
  font-size: 1.05rem;
  line-height: 1.8;
}

/* Images in articles */
.article-content img {
  border-radius: 12px;
  margin: 28px 0;
  border: 1px solid rgba(255,255,255,0.06);
}

/* Strong / Bold */
.article-content strong {
  color: #fafafa;
  font-weight: 600;
}

/* Table of Contents */
.toc {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  padding: 32px;
  border-radius: var(--radius-md);
  margin: 48px 0;
}

.toc h3 {
  margin-top: 0;
  color: #f1f5f9;
  font-size: 1.1rem;
  margin-bottom: 16px;
  font-weight: 700;
}

.toc ul {
  list-style: none;
  padding-left: 0;
  margin-bottom: 0;
}

.toc li {
  margin-bottom: 10px;
}

.toc a {
  color: #cbd5e1;
  text-decoration: none;
  font-size: 0.97rem;
  transition: all 0.2s ease;
  display: inline-block;
  line-height: 1.5;
}

.toc a:hover {
  color: #fbbf24;
  padding-left: 6px;
}

/* Highlight Box / Callout */
.highlight-box {
  background: rgba(255,255,255,0.03);
  border-left: 2px solid #a1a1aa;
  padding: 24px;
  margin: 32px 0;
  border-radius: 0 8px 8px 0;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--color-text-muted);
}

.callout-box {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px;
  margin: 40px 0;
}

.callout-box h4 {
  color: var(--color-text);
  font-size: 1.1rem;
  margin-bottom: 12px;
  font-weight: 600;
}

.callout-box p {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--color-text-muted);
}

/* Comparison Tables */
.vs-table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
  font-size: 0.92rem;
}

.vs-table th {
  background: var(--color-bg-card);
  color: var(--color-text);
  padding: 16px 20px;
  text-align: left;
  font-weight: 600;
  font-size: 0.9rem;
  border-bottom: 1px solid var(--color-border);
}

.vs-table td {
  padding: 16px 20px;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text-muted);
  vertical-align: top;
}

.vs-table tr:hover td {
  background: rgba(255,255,255,0.02);
}

/* Stat Grid (in articles) */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin: 32px 0;
}
@media (min-width: 640px) {
  .stat-grid { grid-template-columns: repeat(4, 1fr); }
}

.stat-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  text-align: left;
}

.stat-card .number {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.2;
}

.stat-card .desc {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-top: 8px;
  font-weight: 500;
}

/* Feature Grid */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 28px 0;
}

.feature-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 28px;
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--color-border);
}

.feature-card h4 {
  font-size: 1.05rem;
  color: var(--color-text);
  margin-bottom: 12px;
  margin-top: 0;
  font-weight: 600;
}

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

.feature-card .feat-icon {
  font-size: 1.8rem;
  margin-bottom: 12px;
  display: block;
}

/* Prompt Example Box */
.prompt-example {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  margin: 32px 0;
}

.prompt-example .label {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 12px;
}

/* Badges (in articles) */
.badge {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 700;
  margin-right: 6px;
}

.badge-beginner { background: rgba(16,185,129,0.15); color: #34d399; }
.badge-intermediate { background: rgba(245,158,11,0.15); color: #fbbf24; }
.badge-advanced { background: rgba(239,68,68,0.15); color: #f87171; }

/* Client Logo Chips */
.client-logos {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
  margin: 24px 0;
}

.client-logo {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 10px;
  padding: 10px 22px;
  font-size: 0.88rem;
  font-weight: 600;
  color: #e2e8f0;
}

/* Company / Profile Cards */
.company-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  margin: 24px 0;
}

.company-card h4 {
  font-size: 1.1rem;
  color: var(--color-text);
  margin-bottom: 6px;
  font-weight: 600;
}

.company-card .role {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  display: block;
  margin-bottom: 12px;
  font-weight: 500;
  letter-spacing: 0.02em;
}

.company-card p {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* Timeline (in articles) */
.timeline-section {
  position: relative;
  padding-left: 24px;
  margin: 32px 0;
}

.timeline-section::before {
  content: '';
  position: absolute;
  left: 6px;
  top: 6px;
  bottom: 6px;
  width: 1px;
  background: var(--color-border);
}

.timeline-section .timeline-item {
  position: relative;
  margin-bottom: 24px;
  padding: 20px 24px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.timeline-section .timeline-item::before {
  content: '';
  position: absolute;
  left: -22px;
  top: 24px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-text-muted);
  box-shadow: 0 0 0 4px var(--color-bg);
}

.timeline-section .timeline-item .date {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  font-weight: 500;
  letter-spacing: 0.02em;
}

.timeline-section .timeline-item .event {
  font-size: 1rem;
  color: var(--color-text);
  font-weight: 600;
  margin-top: 6px;
}

.timeline-section .timeline-item .detail {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-top: 8px;
  line-height: 1.6;
}

/* Flow Diagram */
.flow-diagram {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  flex-wrap: wrap;
  margin: 32px 0;
  padding: 24px;
  background: rgba(99,102,241,0.03);
  border: 1px solid rgba(99,102,241,0.12);
  border-radius: 16px;
}

.flow-step {
  text-align: center;
  padding: 14px 10px;
  min-width: 100px;
}

.flow-step .icon { font-size: 2rem; margin-bottom: 8px; display: block; }
.flow-step .step-label { font-size: 0.82rem; font-weight: 700; color: #f1f5f9; }
.flow-step .step-desc { font-size: 0.68rem; color: #94a3b8; margin-top: 3px; }
.flow-arrow { font-size: 1.4rem; color: #818cf8; padding: 0 2px; }

/* Article Share Section */
.article-share {
  margin: 48px 0 0;
  padding-top: 28px;
  border-top: 1px solid rgba(255,255,255,0.06);
  text-align: center;
}

/* Article Responsive */
@media (max-width: 768px) {
  .article-container { padding: 0 16px 40px; }
  .article-header { margin-top: 80px; }
  .article-header h1 { font-size: 1.5rem; }
  .article-content { font-size: 1rem; line-height: 1.85; }
  .article-content h2 { font-size: 1.4rem; margin-top: 40px; }
  .article-content h3 { font-size: 1.15rem; margin-top: 32px; }
  .stat-grid { grid-template-columns: repeat(2, 1fr); }
  .feature-grid { grid-template-columns: 1fr; }
  .flow-diagram { flex-direction: column; }
  .flow-arrow { transform: rotate(90deg); }
  .vs-table { font-size: 0.82rem; }
  .vs-table th, .vs-table td { padding: 10px 8px; }
}

@media (max-width: 480px) {
  .article-header h1 { font-size: 1.3rem; }
  .article-content { font-size: 0.95rem; }
  .stat-grid { grid-template-columns: 1fr 1fr; gap: 10px; }
  .stat-card .number { font-size: 1.4rem; }
  .client-logos { gap: 8px; }
  .client-logo { padding: 8px 14px; font-size: 0.8rem; }
}