:root {
  --blue: #2563eb;
  --blue-dark: #1d4ed8;
  --blue-light: #eff6ff;
  --blue-soft: #dbeafe;
  --text: #0f172a;
  --text-muted: #475569;
  --bg: #ffffff;
  --bg-subtle: #f8fafc;
  --border: #e2e8f0;
  --shadow: 0 10px 40px -10px rgba(15, 23, 42, 0.1);
  --radius: 16px;
  --radius-sm: 10px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Inter", "Noto Sans JP", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  width: min(1120px, 92%);
  margin: 0 auto;
}

.container.narrow {
  width: min(720px, 92%);
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.logo {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--blue);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: 28px;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--text);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s, background 0.15s;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--blue);
  color: #fff;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.28);
}

.btn-primary:hover {
  background: var(--blue-dark);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.35);
}

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

.btn-secondary:hover {
  background: var(--bg-subtle);
}

.btn-small {
  padding: 8px 18px;
  font-size: 0.85rem;
}

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

/* Hero */
.hero {
  padding: 100px 0 120px;
  background:
    radial-gradient(circle at 90% 10%, var(--blue-light) 0%, transparent 35%),
    radial-gradient(circle at 10% 80%, var(--blue-soft) 0%, transparent 30%);
}

.hero-inner {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 64px;
  align-items: center;
}

.badge {
  display: inline-block;
  padding: 6px 14px;
  border-radius: 999px;
  background: var(--blue-light);
  color: var(--blue-dark);
  font-size: 0.8rem;
  font-weight: 700;
  margin-bottom: 18px;
}

h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  line-height: 1.18;
  letter-spacing: -0.03em;
  margin: 0 0 20px;
  font-weight: 900;
}

.lead {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin: 0 0 32px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.hero-visual {
  display: flex;
  justify-content: center;
}

/* Cards */
.chat-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.preview-card {
  width: 100%;
  max-width: 380px;
  transform: rotate(1.5deg);
}

.preview-card .choices {
  opacity: 0.7;
  pointer-events: none;
}

/* Demo section */
.demo-section {
  padding: 100px 0;
  background: var(--bg-subtle);
}

.section-head {
  text-align: center;
  margin-bottom: 48px;
}

.section-head h2 {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  margin: 0 0 12px;
  font-weight: 800;
}

.section-head p {
  color: var(--text-muted);
  margin: 0;
}

.url-form label {
  display: block;
  font-weight: 700;
  margin-bottom: 10px;
  font-size: 0.95rem;
}

.input-row {
  display: flex;
  gap: 12px;
}

.input-row input {
  flex: 1;
  padding: 14px 18px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.input-row input:focus {
  border-color: var(--blue);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

.demo-frame {
  border-radius: calc(var(--radius) + 4px);
  background: linear-gradient(135deg, #f472b6, #facc15, #4ade80, #38bdf8, #a78bfa, #f472b6);
  background-size: 200% 200%;
  animation: rainbowBorder 6s ease infinite;
  padding: 4px;
  box-shadow: var(--shadow);
}

.demo-frame-inner {
  background: #fff;
  border-radius: var(--radius);
  overflow: hidden;
  padding: 32px;
}

/* Loading */
.loading[hidden] {
  display: none;
}

.loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 48px 0;
  gap: 16px;
  color: var(--text-muted);
}

.spinner {
  width: 44px;
  height: 44px;
  border: 4px solid var(--blue-soft);
  border-top-color: var(--blue);
  border-radius: 50%;
  animation: spin 0.9s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Chat */
.chat-app[hidden] {
  display: none;
}

.chat-app {
  margin-top: 24px;
  position: relative;
  border-radius: calc(var(--radius) + 4px);
  background: linear-gradient(135deg, #f472b6, #facc15, #4ade80, #38bdf8, #a78bfa, #f472b6);
  background-size: 200% 200%;
  animation: rainbowBorder 6s ease infinite;
  padding: 4px;
  box-shadow: var(--shadow);
}

@keyframes rainbowBorder {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.chat-app-inner {
  background: #fff;
  border-radius: var(--radius);
  overflow: hidden;
}

.chat-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  background: var(--bg-subtle);
  border-bottom: 1px solid var(--border);
}

.step-count {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--blue-dark);
  background: var(--blue-light);
  padding: 4px 10px;
  border-radius: 999px;
  white-space: nowrap;
}

.store-info {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 6px;
  font-size: 1rem;
}

.store-name-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  width: 100%;
}

.store-category {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 999px;
  background: var(--blue-light);
  color: var(--blue-dark);
  font-size: 0.75rem;
  font-weight: 700;
  white-space: nowrap;
}

.store-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.price-level {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border-radius: 999px;
  background: #fff;
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-weight: 700;
  font-size: 0.8rem;
}

.store-info strong {
  font-weight: 700;
  line-height: 1.4;
}

.rating {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  border-radius: 999px;
  background: #fff;
  border: 1px solid var(--border);
  color: #f59e0b;
  font-weight: 700;
  font-size: 0.85rem;
}

.status {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 600;
}

.chat-body {
  min-height: 320px;
  max-height: 480px;
  overflow-y: auto;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  scroll-behavior: smooth;
}

.message {
  max-width: 82%;
  padding: 14px 18px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  line-height: 1.55;
  animation: popIn 0.35s ease-out both;
}

.message p {
  margin: 0;
}

.message-row {
  display: flex;
  align-items: flex-end;
  gap: 8px;
  width: 100%;
}

.message-row.bot {
  align-items: flex-start;
}

.message-row.user {
  justify-content: flex-end;
}

.avatar {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
}

.message.bot {
  align-self: flex-start;
  background: var(--bg-subtle);
  color: var(--text);
  border-bottom-left-radius: 4px;
}

.message.user {
  align-self: flex-end;
  background: var(--blue);
  color: #fff;
  border-bottom-right-radius: 4px;
}

@keyframes popIn {
  from {
    opacity: 0;
    transform: translateY(10px) scale(0.98);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

.choices,
.chat-choices {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  padding: 0 20px 20px;
}

.choice,
.chat-choices button {
  padding: 10px 18px;
  border-radius: 999px;
  border: 2px solid #94a3b8;
  background: #fff;
  color: var(--text);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s, color 0.15s;
  animation: popIn 0.3s ease-out both;
}

.choice:hover,
.chat-choices button:hover {
  border-color: var(--blue);
  color: var(--blue);
  background: var(--blue-light);
}

.choice:disabled,
.chat-choices button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.choice.selected {
  background: var(--blue);
  color: #fff;
  border-color: var(--blue);
}

.choice-next {
  width: 100%;
  margin-top: 8px;
}

.preview-card .chat-body {
  min-height: auto;
  max-height: none;
}

/* Final card inside chat */
.final-card {
  background: var(--blue-light);
  border: 1px solid var(--blue-soft);
  border-radius: var(--radius-sm);
  padding: 18px;
  margin-top: 6px;
  animation: popIn 0.4s ease-out both;
}

.final-card p {
  margin: 0 0 16px;
  color: var(--text);
  font-size: 0.95rem;
  line-height: 1.6;
}

.final-card .btn {
  width: 100%;
}

/* Features */
.features-section {
  padding: 100px 0;
}

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

.feature {
  padding: 28px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #fff;
  transition: box-shadow 0.2s, transform 0.2s;
}

.feature:hover {
  box-shadow: var(--shadow);
  transform: translateY(-3px);
}

.feature-icon {
  font-size: 1.8rem;
  margin-bottom: 14px;
}

.feature h3 {
  margin: 0 0 10px;
  font-size: 1.1rem;
  font-weight: 700;
}

.feature p {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* CTA */
.cta-section {
  padding: 100px 0;
  text-align: center;
  background: var(--blue-light);
}

.cta-section h2 {
  font-size: clamp(1.5rem, 4vw, 2rem);
  margin: 0 0 14px;
  font-weight: 800;
}

.cta-section p {
  color: var(--text-muted);
  margin: 0 0 28px;
}

/* Footer */
.site-footer {
  padding: 32px 0;
  text-align: center;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.9rem;
}

.site-footer p {
  margin: 0;
}

/* Responsive */
@media (max-width: 860px) {
  .hero-inner {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .hero {
    padding: 70px 0 90px;
  }

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

  .nav-links {
    display: none;
  }
}

@media (max-width: 520px) {
  .input-row {
    flex-direction: column;
  }

  .input-row .btn {
    width: 100%;
  }

  .hidden-sp {
    display: none;
  }

  .demo-card {
    padding: 22px;
  }

  .message {
    max-width: 92%;
  }
}