:root {
  --primary-color: #007AFF; /* iOS Blue */
  --primary-dark: #0056b3;
  --secondary-color: #5856D6; /* iOS Indigo */
  --accent-color: #FF2D55; /* iOS Pink */
  --text-primary: #1D1D1F;
  --text-secondary: #86868B;
  --bg-body: #F5F5F7;
  --bg-white: #FFFFFF;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.12);
  --radius-md: 12px;
  --radius-lg: 24px;
  --container-width: 1080px;
  --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

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

body {
  font-family: "SF Pro JP", "SF Pro Text", "Noto Sans JP", sans-serif;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-body);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

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

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

.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ヘッダー */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  z-index: 1000;
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
  transition: transform 0.3s ease;
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

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

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color 0.2s ease;
}

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

.header-cta {
  background: var(--text-primary);
  color: white !important;
  padding: 8px 20px;
  border-radius: 99px;
  font-size: 0.9rem !important;
}

.header-cta:hover {
  background: #000;
  transform: scale(1.02);
}

/* モバイルメニュー */
.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--text-primary);
  cursor: pointer;
}

/* ヒーローセクション */
.hero {
  padding: 160px 0 100px;
  background: linear-gradient(180deg, #FFFFFF 0%, #F5F5F7 100%);
  text-align: center;
  overflow: hidden;
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero-tag {
  display: inline-block;
  background: rgba(0, 122, 255, 0.1);
  color: var(--primary-color);
  padding: 6px 16px;
  border-radius: 99px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 24px;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 24px;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, #1D1D1F 0%, #434344 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 40px;
  line-height: 1.8;
}

.store-btn {
  display: inline-block;
  transition: transform 0.2s ease;
}

.store-btn:hover {
  transform: translateY(-2px);
}

.store-btn img {
  height: 56px;
}

/* 問題提起 */
.problem {
  padding: 80px 0;
  background: var(--bg-white);
}

.section-title {
  text-align: center;
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-width: 600px;
  margin: 0 auto 60px;
}

/* 機能セクション（交互レイアウト） */
.features {
  padding: 0 0 100px;
  background: var(--bg-body);
}

.feature-block {
  padding: 80px 0;
}

.feature-block:nth-child(even) {
  background: var(--bg-white);
}

.feature-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px;
}

.feature-block:nth-child(even) .feature-container {
  direction: rtl; /* 画像とテキストを入れ替える */
}

.feature-block:nth-child(even) .feature-text {
  direction: ltr; /* テキストの向きは戻す */
}

.feature-image {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  transform: perspective(1000px) rotateY(0deg);
  transition: transform 0.5s ease;
}

.feature-image:hover {
  transform: perspective(1000px) rotateY(2deg);
}

.feature-text h3 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 24px;
  letter-spacing: -0.02em;
}

.feature-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: var(--bg-body);
  border-radius: 12px;
  font-size: 1.5rem;
  margin-bottom: 24px;
}

.feature-text p {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.feature-highlight {
  display: inline-block;
  font-weight: 600;
  color: var(--primary-color);
  margin-top: 8px;
}

/* タグセクション */
.tags-section {
  padding: 100px 0;
  background: var(--bg-white);
  text-align: center;
}

.tags-wrapper {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 16px;
  max-width: 800px;
  margin: 40px auto 0;
}

.tag-pill {
  padding: 12px 24px;
  background: var(--bg-body);
  border-radius: 99px;
  font-weight: 600;
  color: var(--text-primary);
  transition: var(--transition);
}

.tag-pill:hover {
  background: var(--primary-color);
  color: white;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* CTA */
.cta-section {
  padding: 120px 0;
  background: #1D1D1F;
  color: white;
  text-align: center;
}

.cta-content h2 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 24px;
}

.cta-content p {
  color: #86868B;
  font-size: 1.25rem;
  margin-bottom: 40px;
}

/* フッター */
footer {
  background: var(--bg-body);
  padding: 60px 0 30px;
  border-top: 1px solid rgba(0, 0, 0, 0.05);
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  margin-bottom: 40px;
}

.footer-logo {
  font-weight: 700;
  color: var(--text-primary);
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.copyright {
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid rgba(0, 0, 0, 0.05);
}

/* アニメーション */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.8s cubic-bezier(0.25, 0.8, 0.25, 1);
}

.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

/* レスポンシブ */
@media (max-width: 900px) {
  .feature-container {
    grid-template-columns: 1fr;
    gap: 40px;
    direction: ltr !important;
  }
  
  .feature-image {
    order: -1; /* 画像を上に */
    max-width: 600px;
    margin: 0 auto;
  }
  
  .feature-text {
    text-align: center;
    direction: ltr !important;
  }
  
  .hero h1 {
    font-size: 2.5rem;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    width: 100%;
    background: white;
    flex-direction: column;
    padding: 20px 0;
    box-shadow: var(--shadow-md);
  }

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

  .mobile-menu-toggle {
    display: block;
  }
  
  .container {
    padding: 0 20px;
  }
}