:root {
  --primary-bg: #0b0f1a;
  --secondary-bg: #0f1524;
  --card-bg: #141a2a;
  --accent-color: #00e5ff;
  --accent-secondary: #00ffc8;
  --text-primary: #eaf0ff;
  --text-secondary: #c8d0e0;
  --text-muted: #7a8299;
  --border-color: rgba(255, 255, 255, 0.12);
  --shadow-light: rgba(0, 229, 255, 0.12);
  --shadow-dark: rgba(0, 0, 0, 0.45);
  --glass-bg: rgba(255, 255, 255, 0.08);
  --glass-border: rgba(255, 255, 255, 0.18);
  --glass-blur: 14px;
  --accent-danger: #ff4d4f;
}

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

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background:
    radial-gradient(1100px 780px at 12% 8%, rgba(0, 229, 255, 0.09), transparent 60%),
    radial-gradient(1000px 700px at 88% 15%, rgba(0, 153, 255, 0.08), transparent 60%),
    radial-gradient(900px 900px at 50% 100%, rgba(255, 255, 255, 0.04), transparent 60%),
    var(--primary-bg);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

body::before {
  content: '';
  position: fixed;
  inset: -20vmax;
  pointer-events: none;
  background:
    radial-gradient(45vmax 35vmax at 20% 15%, rgba(0, 229, 255, 0.14), transparent 60%),
    radial-gradient(40vmax 40vmax at 80% 10%, rgba(0, 153, 255, 0.12), transparent 60%),
    radial-gradient(55vmax 45vmax at 60% 90%, rgba(0, 255, 170, 0.08), transparent 60%),
    radial-gradient(120px 120px at 12% 28%, rgba(0,229,255,0.35) 0 60%, rgba(0,229,255,0) 62%),
    radial-gradient(160px 160px at 85% 24%, rgba(0,153,255,0.28) 0 58%, rgba(0,153,255,0) 60%),
    radial-gradient(100px 100px at 70% 78%, rgba(0,255,170,0.25) 0 55%, rgba(0,255,170,0) 57%),
    radial-gradient(140px 140px at 35% 85%, rgba(255,255,255,0.12) 0 50%, rgba(255,255,255,0) 52%);
  filter: blur(40px) saturate(110%);
  animation: auroraFloat 18s ease-in-out infinite alternate;
  z-index: -1;
}

body::after {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255,255,255,0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.04) 1px, transparent 1px);
  background-size: 48px 48px, 48px 48px;
  background-position: 0 0, 0 0;
  mix-blend-mode: overlay;
  z-index: -1;
}

@keyframes auroraFloat {
  0% { transform: translate3d(0, 0, 0) scale(1); opacity: 0.85; }
  50% { transform: translate3d(-2%, 1.5%, 0) scale(1.03); opacity: 0.95; }
  100% { transform: translate3d(2%, -2%, 0) scale(1.02); opacity: 0.9; }
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.hero-section {
  padding: 40px 0 30px;
  background: linear-gradient(135deg, rgba(255,255,255,0.06), rgba(255,255,255,0.02));
  border-bottom: 1px solid var(--glass-border);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.hero-content {
  max-width: 1200px;
  text-align: left;
}

.main-title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  margin-bottom: 0.8rem;
  background: linear-gradient(135deg, var(--accent-color) 0%, #ffffff 50%, var(--accent-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.02em;
  text-shadow: 0 2px 16px rgba(0, 212, 170, 0.15), 0 2px 18px rgba(255, 107, 107, 0.12);
}

.subtitle {
  font-size: 1.1rem;
  color: var(--text-secondary);
  font-weight: 400;
  max-width: 500px;
  margin: 0;
}

.content-wrapper {
  padding: 60px 0;
}

section {
  margin-bottom: 80px;
}

.section-header {
  text-align: center;
  margin-bottom: 50px;
}

.section-header h2 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.section-description {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

.chat-example {
  background: var(--glass-bg);
  border-radius: 16px;
  padding: 24px;
  margin: 40px 0;
  border: 1px solid var(--glass-border);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.35);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
}

.chat-header {
  font-weight: 600;
  margin-bottom: 20px;
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.inefficient .chat-header {
  background: rgba(255, 77, 79, 0.12);
  color: var(--accent-danger);
  border: 1px solid rgba(255, 77, 79, 0.28);
}

.efficient .chat-header {
  background: rgba(0, 212, 170, 0.1);
  color: var(--accent-color);
  border: 1px solid rgba(0, 212, 170, 0.2);
}

.polite .chat-header {
  background: linear-gradient(135deg, rgba(0, 212, 170, 0.1), rgba(255, 107, 107, 0.1));
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.message-thread {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.message {
  display: flex;
  align-items: flex-end;
  gap: 12px;
}

.message.sender {
  justify-content: flex-end;
}

.message-bubble {
  max-width: 70%;
  padding: 12px 16px;
  border-radius: 18px;
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.sender .message-bubble {
  background: var(--accent-color);
  color: var(--primary-bg);
  border-bottom-right-radius: 6px;
  box-shadow: 0 10px 30px rgba(0, 229, 255, 0.25), 0 0 0 1px rgba(255,255,255,0.08) inset;
}

.receiver .message-bubble {
  background: var(--glass-bg);
  color: var(--text-primary);
  border-bottom-left-radius: 6px;
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(calc(var(--glass-blur) - 2px));
  -webkit-backdrop-filter: blur(calc(var(--glass-blur) - 2px));
}

.message-bubble .text {
  font-size: 0.95rem;
  line-height: 1.4;
}

.timestamp {
  font-size: 0.75rem;
  opacity: 0.7;
  align-self: flex-end;
}

.waiting-indicator {
  text-align: center;
  padding: 16px;
  color: var(--text-muted);
  font-style: italic;
  background: rgba(255, 107, 107, 0.05);
  border-radius: 8px;
  border: 1px dashed rgba(255, 107, 107, 0.2);
}

.insight-box {
  background: linear-gradient(135deg, var(--secondary-bg), var(--card-bg));
  border-radius: 12px;
  padding: 24px;
  margin: 30px 0;
  border-left: 4px solid var(--accent-color);
  display: flex;
  align-items: center;
  gap: 16px;
}

.insight-icon {
  font-size: 2rem;
  flex-shrink: 0;
}

.insight-box p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 1rem;
}

.benefits-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
  margin-top: 40px;
}

.benefit-card {
  background: var(--glass-bg);
  border-radius: 12px;
  padding: 32px 24px;
  text-align: center;
  border: 1px solid var(--glass-border);
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
}

.benefit-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-color), var(--accent-secondary));
  transform: scaleX(0);
  transition: transform 0.3s ease;
}

.benefit-card:hover::before {
  transform: scaleX(1);
}

.benefit-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 50px rgba(0, 0, 0, 0.45);
}

.benefit-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}

.benefit-icon svg { width: 2.4rem; height: 2.4rem; }
.icon { width: 1.15em; height: 1.15em; vertical-align: -0.15em; margin-right: 8px; }
.icon--lg { width: 1.35em; height: 1.35em; }

.benefit-card h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.benefit-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin: 0;
}

.content-card {
  background: var(--glass-bg);
  border-radius: 16px;
  padding: 40px;
  border: 1px solid var(--glass-border);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.35);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
}

.content-card h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 32px;
  color: var(--text-primary);
}

.explanation-grid {
  display: grid;
  gap: 32px;
  margin-top: 32px;
}

.explanation-item {
  display: flex;
  gap: 24px;
  align-items: flex-start;
}

.number {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-color), var(--accent-secondary));
  color: var(--primary-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
}

.explanation-content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.explanation-content p {
  color: var(--text-secondary);
  margin: 0;
  line-height: 1.6;
}

.tips-section h2 {
  font-size: 2.5rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 50px;
  color: var(--text-primary);
}

.tips-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
  gap: 32px;
  margin-top: 40px;
}

.tip-card {
  background: var(--glass-bg);
  border-radius: 16px;
  padding: 32px;
  border: 1px solid var(--glass-border);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.35);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
}

.tip-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 24px;
}

.tip-number {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--accent-color);
  color: var(--primary-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
}

.tip-header h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
}

.avoid-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.avoid-item {
  padding: 12px 16px;
  background: rgba(255, 107, 107, 0.1);
  border: 1px solid rgba(255, 107, 107, 0.2);
  border-radius: 8px;
  color: var(--accent-secondary);
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
}

.formula {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  justify-content: center;
}

.formula-part {
  padding: 16px 24px;
  background: linear-gradient(135deg, var(--accent-color), var(--accent-secondary));
  color: var(--primary-bg);
  border-radius: 12px;
  font-weight: 600;
  text-align: center;
  flex: 1;
  min-width: 120px;
}

.formula-plus {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-color);
}

.note {
  margin-top: 24px;
  padding: 16px;
  background: rgba(0, 212, 170, 0.1);
  border: 1px solid rgba(0, 212, 170, 0.2);
  border-radius: 8px;
  color: var(--text-secondary);
  font-style: italic;
}

.site-footer {
  background: linear-gradient(180deg, rgba(255,255,255,0.06), rgba(255,255,255,0.02));
  border-top: 1px solid var(--glass-border);
  padding: 20px 0;
  margin-top: 60px;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.footer-content {
  text-align: center;
  max-width: 1200px;
}

.footer-message p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.footer-credit {
  color: var(--text-muted);
  font-size: 0.8rem;
}

@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }
  
  .hero-section {
    padding: 30px 0 20px;
  }
  
  .main-title {
    font-size: 1.8rem;
  }
  
  .subtitle {
    font-size: 1rem;
  }
  
  .content-wrapper {
    padding: 40px 0;
  }
  
  section {
    margin-bottom: 60px;
  }
  
  .section-header h2 {
    font-size: 2rem;
  }
  
  .chat-example {
    padding: 20px;
  }
  
  .message-bubble {
    max-width: 85%;
  }
  
  .benefits-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  
  .content-card {
    padding: 24px;
  }
  
  .explanation-item {
    flex-direction: column;
    gap: 16px;
  }
  
  .tips-container {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  
  .formula {
    flex-direction: column;
    gap: 12px;
  }
  
  .formula-plus {
    transform: rotate(90deg);
  }
}

@media (max-width: 768px) {
  .icon { width: 1em; height: 1em; margin-right: 6px; }
  .icon--lg { width: 1.15em; height: 1.15em; }
  .benefit-icon svg { width: 2rem; height: 2rem; }
  .insight-icon { font-size: 1.6rem; }
}

@media (max-width: 480px) {
  .main-title {
    font-size: 2rem;
  }
  
  .section-header h2 {
    font-size: 1.75rem;
  }
  
  .chat-example {
    padding: 16px;
  }
  
  .content-card {
    padding: 20px;
  }
  
  .tip-card {
    padding: 24px;
  }
  
  .tips-container {
    grid-template-columns: 1fr;
  }

  .icon { width: 0.95em; height: 0.95em; margin-right: 6px; }
  .icon--lg { width: 1.05em; height: 1.05em; }
  .benefit-icon svg { width: 1.6rem; height: 1.6rem; }
  .insight-icon { font-size: 1.4rem; }

  article {
    margin: 0.25rem;
    padding: 1rem;
    border-radius: 12px;
  }
  
  h1 {
    font-size: 1.5rem;
  }
  
  .dialog-block {
    margin: 1rem -0.25rem;
    padding: 1rem;
  }
  
  footer .row {
    padding: 0 1rem;
  }
}

 

@media (max-width: 320px) {
  html {
    font-size: 13px;
  }
  
  article {
    padding: 0.75rem;
  }
  
  h1 {
    font-size: 1.3rem;
  }
}

@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
  article {
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
  }
  
  .dialog-block {
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --glass-bg: rgba(255, 255, 255, 0.08);
    --glass-border: rgba(255, 255, 255, 0.15);
    --text-primary: rgba(255, 255, 255, 0.95);
    --text-secondary: rgba(255, 255, 255, 0.75);
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  body::before {
    animation: none;
  }
}

a:focus,
.dialog-line .content:focus {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}