:root {
  --bg: #09090f;
  --bg2: #13131e;
  --bg3: #1c1c2e;
  --primary: #7c6fff;
  --primary-dim: #5b52cc;
  --accent: #ff7eb3;
  --text: #e2e8f0;
  --text2: #8892a4;
  --border: #252538;
  --card: #16162a;
  --radius: 14px;
}

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

body {
  font-family: 'Helvetica Neue', 'Hiragino Sans', 'Noto Sans JP', Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 16px;
}

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

/* ============ NAV ============ */
nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(9, 9, 15, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between;
  height: 60px;
}
.nav-logo { font-size: 1.2rem; font-weight: 700; color: var(--text); }
.nav-logo span { color: var(--primary); }
.nav-links { display: flex; gap: 24px; font-size: 0.9rem; color: var(--text2); }
.nav-links a:hover { color: var(--text); }
.btn-nav {
  background: var(--primary); color: #fff;
  padding: 8px 18px; border-radius: 8px;
  font-size: 0.85rem; font-weight: 600;
  transition: background 0.2s;
}
.btn-nav:hover { background: var(--primary-dim); color: #fff; }

/* ============ HERO ============ */
.hero {
  max-width: 860px; margin: 0 auto;
  padding: 90px 24px 70px;
  text-align: center;
}
.hero-badge {
  display: inline-block;
  background: rgba(124, 111, 255, 0.15);
  color: var(--primary);
  border: 1px solid rgba(124, 111, 255, 0.3);
  border-radius: 100px;
  padding: 4px 16px;
  font-size: 0.8rem; font-weight: 600;
  margin-bottom: 28px;
  letter-spacing: 0.05em;
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}
.hero h1 em { font-style: normal; color: var(--primary); }
.hero p {
  font-size: 1.1rem; color: var(--text2);
  max-width: 560px; margin: 0 auto 36px;
}
.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.btn-primary {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--primary); color: #fff;
  padding: 14px 28px; border-radius: 12px;
  font-size: 1rem; font-weight: 700;
  transition: transform 0.2s, background 0.2s;
  box-shadow: 0 4px 24px rgba(124, 111, 255, 0.3);
}
.btn-primary:hover { background: var(--primary-dim); transform: translateY(-2px); color: #fff; }
.btn-secondary {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--bg3); color: var(--text);
  border: 1px solid var(--border);
  padding: 14px 28px; border-radius: 12px;
  font-size: 1rem; font-weight: 600;
  transition: background 0.2s;
}
.btn-secondary:hover { background: var(--bg2); color: var(--text); }

/* ============ APP PREVIEW ============ */
.preview {
  max-width: 900px; margin: 0 auto 90px;
  padding: 0 24px;
  display: flex; justify-content: center;
}
.preview-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 32px;
  width: 100%;
  box-shadow: 0 24px 80px rgba(0,0,0,0.5);
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px;
}
.preview-block {
  background: var(--bg3); border-radius: var(--radius);
  padding: 20px; text-align: center;
}
.preview-block .icon { font-size: 2rem; margin-bottom: 8px; }
.preview-block .label { font-size: 0.8rem; color: var(--text2); }
.preview-block .value { font-size: 1rem; font-weight: 700; margin-top: 4px; }

/* ============ SECTION ============ */
section { padding: 80px 24px; }
.container { max-width: 900px; margin: 0 auto; }
.section-tag {
  font-size: 0.75rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.1em;
  color: var(--primary); margin-bottom: 12px;
}
.section-title {
  font-size: clamp(1.5rem, 3vw, 2.2rem);
  font-weight: 800; line-height: 1.2; margin-bottom: 16px;
  letter-spacing: -0.01em;
}
.section-lead { color: var(--text2); font-size: 1.05rem; max-width: 600px; margin-bottom: 48px; }

/* ============ FEATURES ============ */
.features { background: var(--bg2); }
.features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 20px; }
.feature-card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px;
  transition: border-color 0.2s, transform 0.2s;
}
.feature-card:hover { border-color: var(--primary); transform: translateY(-3px); }
.feature-icon { font-size: 2rem; margin-bottom: 14px; }
.feature-card h3 { font-size: 1rem; font-weight: 700; margin-bottom: 8px; }
.feature-card p { font-size: 0.9rem; color: var(--text2); }

/* ============ LESSONS ============ */
.lessons-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 14px; }
.lesson-pill {
  background: var(--bg3); border: 1px solid var(--border);
  border-radius: 10px; padding: 14px 16px;
  display: flex; align-items: center; gap: 10px;
}
.lesson-num { color: var(--primary); font-weight: 700; font-size: 0.85rem; min-width: 28px; }
.lesson-name { font-size: 0.9rem; }

/* ============ STEPS ============ */
.steps { background: var(--bg2); }
.steps-list { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 24px; }
.step { display: flex; flex-direction: column; align-items: flex-start; gap: 12px; }
.step-num {
  width: 44px; height: 44px; border-radius: 50%;
  background: rgba(124,111,255,0.15); border: 1px solid rgba(124,111,255,0.3);
  color: var(--primary); font-weight: 800; font-size: 1.1rem;
  display: flex; align-items: center; justify-content: center;
}
.step h3 { font-size: 1rem; font-weight: 700; }
.step p { font-size: 0.9rem; color: var(--text2); }

/* ============ FORMULA DEMO ============ */
.formula-demo {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px;
  font-family: 'Courier New', monospace;
  margin-top: 20px;
}
.formula-demo .input-line { color: var(--text2); font-size: 0.9rem; margin-bottom: 8px; }
.formula-demo .output-line { color: var(--primary); font-size: 1.2rem; font-weight: 700; }
.formula-demo .steps-line { margin-top: 16px; font-size: 0.85rem; color: var(--text2); }
.formula-demo .step-item { margin-top: 6px; padding-left: 16px; border-left: 2px solid var(--border); }

/* ============ DOWNLOAD CTA ============ */
.cta { text-align: center; }
.cta .section-title { max-width: 500px; margin: 0 auto 16px; }
.cta p { color: var(--text2); max-width: 400px; margin: 0 auto 36px; }

/* ============ FOOTER ============ */
footer {
  background: var(--bg2);
  border-top: 1px solid var(--border);
  padding: 40px 24px;
  text-align: center;
}
.footer-inner { max-width: 900px; margin: 0 auto; }
.footer-links { display: flex; justify-content: center; gap: 24px; margin-bottom: 16px; flex-wrap: wrap; }
.footer-links a { color: var(--text2); font-size: 0.9rem; }
.footer-copy { color: var(--text2); font-size: 0.85rem; }

/* ============ LEGAL PAGES ============ */
.legal-header {
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  padding: 60px 24px 40px;
  text-align: center;
}
.legal-header h1 { font-size: 2rem; font-weight: 800; }
.legal-header .date { color: var(--text2); font-size: 0.9rem; margin-top: 8px; }
.legal-body {
  max-width: 720px; margin: 60px auto;
  padding: 0 24px 80px;
}
.legal-body h2 {
  font-size: 1.1rem; font-weight: 700;
  margin: 36px 0 12px;
  padding-left: 12px;
  border-left: 3px solid var(--primary);
}
.legal-body p { color: var(--text2); margin-bottom: 12px; font-size: 0.95rem; }
.legal-body ul {
  color: var(--text2); font-size: 0.95rem;
  padding-left: 24px; margin-bottom: 12px;
}
.legal-body ul li { margin-bottom: 6px; }
.legal-body a { color: var(--primary); }

@media (max-width: 600px) {
  .nav-links { display: none; }
  .preview-card { grid-template-columns: 1fr; }
  .hero { padding: 60px 20px 50px; }
}