/* ============================================
   0. CSS Custom Properties
============================================ */
:root {
  --color-gold: #D4AF37;
  --color-gold-light: #e6c85a;
  --color-gold-dark: #b8942d;
  --color-navy: #1B2A4A;
  --color-navy-light: #243560;
  --color-navy-dark: #111c33;
  --color-white: #FFFFFF;
  --color-white-70: rgba(255, 255, 255, 0.7);
  --color-white-50: rgba(255, 255, 255, 0.5);
  --color-white-15: rgba(255, 255, 255, 0.15);

  --font-en: 'Montserrat', sans-serif;
  --font-ja: 'Montserrat', 'Hiragino Kaku Gothic ProN', 'Noto Sans JP', 'Meiryo', sans-serif;

  --section-padding: 120px 0;
  --section-padding-sp: 72px 0;
  --inner-max: 1100px;
  --inner-padding: 0 40px;
  --inner-padding-sp: 0 20px;

  --transition-base: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-ja);
  background-color: var(--color-navy);
  color: var(--color-white);
  line-height: 1.8;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

/* ============================================
   2. Utility
============================================ */
.gold {
  color: var(--color-gold);
}

/* ============================================
   3. Header
============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  padding: 20px 40px;
  transition: background var(--transition-base), padding var(--transition-base);
}

.header.is-scrolled {
  background: rgba(27, 42, 74, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  padding: 12px 40px;
}

.header__inner {
  max-width: var(--inner-max);
  margin: 0 auto;
  display: flex;
  align-items: center;
}

.header__logo-img {
  height: 36px;
  width: auto;
  transition: height var(--transition-base);
}

.header.is-scrolled .header__logo-img {
  height: 28px;
}

/* ============================================
   4. Hero Section
============================================ */
.hero {
  position: relative;
  width: 100%;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  overflow: hidden;
}

/* Background (parallax layer) */
.hero__bg-wrap {
  position: absolute;
  inset: -60px 0;
  z-index: 0;
  overflow: hidden;
}

.hero__bg {
  width: 100%;
  height: 100%;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  will-change: transform;
}

/* Dark overlay for readability */
.hero__overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(27, 42, 74, 0.70) 0%,
    rgba(27, 42, 74, 0.45) 50%,
    rgba(27, 42, 74, 0.80) 100%
  );
  z-index: 1;
}

/* Content */
.hero__content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 140px 40px 40px;
  max-width: 900px;
}

.hero__catch {
  font-family: var(--font-ja);
  font-size: clamp(1.8rem, 4.5vw, 3.2rem);
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1.4;
  margin-bottom: 20px;
  opacity: 0;
  transform: translateY(30px);
}

.hero__sub {
  font-size: clamp(0.95rem, 2vw, 1.2rem);
  color: var(--color-white-70);
  letter-spacing: 0.05em;
  margin-bottom: 40px;
  opacity: 0;
  transform: translateY(30px);
}

.hero__cta {
  opacity: 0;
  transform: translateY(20px);
}

/* 16:9 Hero image */
.hero__image-wrap {
  position: relative;
  z-index: 2;
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 40px 80px;
  opacity: 0;
  transform: translateY(40px);
}

.hero__image {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: 12px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
}

/* ============================================
   5. Button
============================================ */
.btn {
  display: inline-block;
  font-family: var(--font-en);
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.06em;
  padding: 16px 48px;
  border-radius: 60px;
  cursor: pointer;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.btn--gold {
  background: var(--color-gold);
  color: var(--color-white);
  box-shadow: 0 4px 24px rgba(212, 175, 55, 0.3);
}

.btn--gold:hover {
  background: var(--color-gold-light);
  box-shadow: 0 6px 32px rgba(212, 175, 55, 0.5);
  transform: translateY(-2px);
}

.btn--gold:active {
  transform: translateY(0);
}

/* ============================================
   6. Section (shared)
============================================ */
.section {
  padding: var(--section-padding);
}

.section__inner {
  max-width: var(--inner-max);
  margin: 0 auto;
  padding: var(--inner-padding);
}

.section__heading {
  font-family: var(--font-ja);
  font-size: clamp(1.5rem, 3vw, 2.2rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: 60px;
  letter-spacing: 0.06em;
  position: relative;
}

.section__heading::after {
  content: '';
  display: block;
  width: 48px;
  height: 3px;
  background: var(--color-gold);
  margin: 16px auto 0;
  border-radius: 2px;
}

/* ============================================
   7. Concept Section
============================================ */
.concept__body {
  max-width: 760px;
  margin: 0 auto;
  text-align: center;
}

.concept__text {
  font-size: clamp(0.95rem, 1.6vw, 1.08rem);
  line-height: 2;
  color: var(--color-white-70);
  margin-bottom: 24px;
}

.concept__text:last-child {
  margin-bottom: 0;
}

.concept__text strong {
  color: var(--color-gold);
  font-weight: 600;
}

/* ============================================
   8. Features Section
============================================ */
.features {
  background: var(--color-navy-dark);
}

.features__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.feature-card {
  background: var(--color-white-15);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 16px;
  padding: 40px 28px;
  text-align: center;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  opacity: 0;
  transform: translateY(40px);
}

.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.25);
}

.feature-card__icon {
  width: 56px;
  height: 56px;
  margin: 0 auto 24px;
}

.feature-card__icon svg {
  width: 100%;
  height: 100%;
}

.feature-card__title {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 12px;
  letter-spacing: 0.04em;
  color: var(--color-gold);
}

.feature-card__text {
  font-size: 0.9rem;
  color: var(--color-white-70);
  line-height: 1.8;
}

/* ============================================
   9. Steps Section
============================================ */
.steps__timeline {
  max-width: 680px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.step {
  display: flex;
  align-items: flex-start;
  gap: 24px;
  width: 100%;
  opacity: 0;
  transform: translateY(30px);
}

.step__number {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-gold);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-en);
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--color-navy);
}

.step__icon {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
}

.step__icon svg {
  width: 100%;
  height: 100%;
}

.step__body {
  padding-top: 4px;
}

.step__title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 6px;
  letter-spacing: 0.04em;
}

.step__text {
  font-size: 0.92rem;
  color: var(--color-white-70);
  line-height: 1.8;
}

.step__connector {
  width: 2px;
  height: 48px;
  background: linear-gradient(180deg, var(--color-gold), transparent);
  margin: 0 0 0 23px;
  opacity: 0;
}

/* ============================================
   10. Footer
============================================ */
.footer {
  background: var(--color-navy-dark);
  padding: 40px 20px;
  text-align: center;
  border-top: 1px solid var(--color-white-15);
}

.footer__copy {
  font-family: var(--font-en);
  font-size: 0.82rem;
  color: var(--color-white-50);
  letter-spacing: 0.04em;
}

/* ============================================
   11. Responsive — Tablet (768–1023)
============================================ */
@media (max-width: 1023px) {
  .features__grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
  }

  .hero__image-wrap {
    max-width: 88%;
    padding: 0 24px 60px;
  }

  .step {
    gap: 18px;
  }
}

/* ============================================
   12. Responsive — Smartphone (〜767)
============================================ */
@media (max-width: 767px) {
  :root {
    --section-padding: var(--section-padding-sp);
    --inner-padding: var(--inner-padding-sp);
  }

  .header {
    padding: 14px 20px;
  }

  .header.is-scrolled {
    padding: 10px 20px;
  }

  .header__logo-img {
    height: 28px;
  }

  .hero__content {
    padding: 120px 20px 30px;
  }

  .hero__image-wrap {
    max-width: 100%;
    padding: 0 16px 48px;
  }

  .hero__image {
    border-radius: 8px;
  }

  .section__heading {
    margin-bottom: 40px;
  }

  .features__grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .feature-card {
    padding: 32px 24px;
  }

  .step {
    gap: 16px;
  }

  .step__number {
    width: 40px;
    height: 40px;
    font-size: 1rem;
  }

  .step__icon {
    width: 40px;
    height: 40px;
  }

  .step__connector {
    height: 36px;
    margin-left: 19px;
  }
}