/* ============================================
   CSS Custom Properties
   ============================================ */
:root {
  --color-bg: #FAFAFA;
  --color-bg-white: #FFFFFF;
  --color-bg-subtle: #F5F6F8;
  --color-bg-dark: #161631;
  --color-text-primary: #1A1A2E;
  --color-text-secondary: #4A5568;
  --color-text-tertiary: #8892A4;
  --color-text-inverse: #FFFFFF;
  --color-navy: #1B1F6B;
  --color-navy-deep: #141754;
  --color-amber: #F5A623;
  --color-amber-soft: #F7B84E;
  --color-accent: #1B1F6B;
  --color-accent-hover: #141754;
  --color-border: #E2E5EA;
  --color-border-light: #ECEEF2;

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

  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2.5rem;
  --space-xl: 4rem;
  --space-2xl: 6rem;
  --space-3xl: 8rem;
  --space-4xl: 10rem;

  --max-width: 1120px;
  --max-width-narrow: 800px;
  --header-height: 72px;

  --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-ja);
  color: var(--color-text-primary);
  background-color: var(--color-bg-white);
  line-height: 1.8;
  font-weight: 400;
  overflow-x: hidden;
}

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

ul { list-style: none; }

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

/* ============================================
   Utility
   ============================================ */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
}

.container--narrow {
  max-width: var(--max-width-narrow);
  margin: 0 auto;
  padding: 0 2rem;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ============================================
   Section Common
   ============================================ */
.section {
  padding: var(--space-3xl) 0;
}

.section--alt {
  background-color: var(--color-bg-subtle);
}

.section__label {
  font-family: var(--font-en);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-navy);
  margin-bottom: var(--space-sm);
}

.section__heading {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: 0.02em;
  margin-bottom: var(--space-lg);
  color: var(--color-text-primary);
}

/* ============================================
   Reveal Animation
   ============================================ */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s cubic-bezier(0.4, 0, 0.2, 1),
              transform 0.7s cubic-bezier(0.4, 0, 0.2, 1);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-stagger > .reveal:nth-child(2) { transition-delay: 0.1s; }
.reveal-stagger > .reveal:nth-child(3) { transition-delay: 0.2s; }
.reveal-stagger > .reveal:nth-child(4) { transition-delay: 0.25s; }

/* ============================================
   Header
   ============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  z-index: 1000;
  transition: background-color var(--transition-base),
              box-shadow var(--transition-base);
}

.header.is-scrolled {
  background-color: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 1px 0 var(--color-border-light);
}

.header__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.header__logo {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  transition: opacity var(--transition-base);
}

.header__logo:hover {
  opacity: 0.75;
}

.header__logo-mark {
  height: 34px;
  width: auto;
}

.header__logo-name {
  font-family: var(--font-en);
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--color-text-primary);
  line-height: 1;
}

.header__nav {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.header__nav-link {
  font-size: 0.8125rem;
  font-weight: 400;
  color: var(--color-text-secondary);
  transition: color var(--transition-base);
  letter-spacing: 0.02em;
}

.header__nav-link:hover {
  color: var(--color-text-primary);
}

.header__nav-cta {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-bg-white);
  background-color: var(--color-navy);
  padding: 0.5rem 1.25rem;
  border-radius: 3px;
  transition: background-color var(--transition-base);
  letter-spacing: 0.02em;
}

.header__nav-cta:hover {
  background-color: var(--color-navy-deep);
}

/* Hamburger */
.header__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  gap: 5px;
  padding: 0;
}

.header__hamburger-line {
  width: 22px;
  height: 1.5px;
  background-color: var(--color-text-primary);
  transition: transform var(--transition-base), opacity var(--transition-base);
  display: block;
}

.header__hamburger.is-active .header__hamburger-line:nth-child(1) {
  transform: translateY(6.5px) rotate(45deg);
}
.header__hamburger.is-active .header__hamburger-line:nth-child(2) {
  opacity: 0;
}
.header__hamburger.is-active .header__hamburger-line:nth-child(3) {
  transform: translateY(-6.5px) rotate(-45deg);
}

/* Mobile nav */
.mobile-nav {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  z-index: 999;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 2rem;
  opacity: 0;
  transition: opacity var(--transition-base);
}

.mobile-nav.is-open {
  display: flex;
  opacity: 1;
}

.mobile-nav__link {
  font-size: 1.125rem;
  font-weight: 400;
  color: var(--color-text-primary);
  letter-spacing: 0.05em;
}

.mobile-nav__cta {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-bg-white);
  background-color: var(--color-navy);
  padding: 0.75rem 2rem;
  border-radius: 3px;
  margin-top: 1rem;
}

/* ============================================
   Hero
   ============================================ */
.hero {
  min-height: 82vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: var(--header-height);
}

.hero__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
}

/* Subtle geometric background */
.hero__bg::before {
  content: '';
  position: absolute;
  top: -20%;
  right: -8%;
  width: 55%;
  height: 140%;
  background: linear-gradient(145deg, transparent 0%, rgba(27, 31, 107, 0.02) 40%, rgba(27, 31, 107, 0.045) 100%);
  transform: skewX(-12deg);
}

.hero__bg::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--color-border-light);
}

/* Logo watermark */
.hero__watermark {
  position: absolute;
  right: -7%;
  top: 50%;
  transform: translateY(-48%);
  width: 460px;
  height: 460px;
  z-index: 0;
  pointer-events: none;
  animation: watermarkFadeIn 1.8s 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  opacity: 0;
}

.hero__watermark img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

@keyframes watermarkFadeIn {
  to {
    opacity: 0.035;
  }
}

.hero__content {
  position: relative;
  z-index: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-4xl) 2rem;
  width: 100%;
}

.hero__eyebrow {
  font-family: var(--font-en);
  font-size: 0.6875rem;
  font-weight: 400;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-lg);
  opacity: 0;
  transform: translateY(16px);
  animation: heroFadeUp 0.8s 0.3s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.hero__heading {
  font-size: clamp(1.75rem, 4.5vw, 3rem);
  font-weight: 600;
  line-height: 1.6;
  letter-spacing: 0.04em;
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
  opacity: 0;
  transform: translateY(20px);
  animation: heroFadeUp 0.8s 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.hero__description {
  font-size: clamp(0.9375rem, 1.4vw, 1rem);
  line-height: 1.9;
  color: var(--color-text-secondary);
  max-width: 520px;
  margin-bottom: var(--space-xl);
  opacity: 0;
  transform: translateY(20px);
  animation: heroFadeUp 0.8s 0.7s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.hero__actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  opacity: 0;
  transform: translateY(20px);
  animation: heroFadeUp 0.8s 0.9s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes heroFadeUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ============================================
   Buttons
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-ja);
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  padding: 0.875rem 2rem;
  border-radius: 3px;
  border: none;
  cursor: pointer;
  transition: all var(--transition-base);
}

.btn--primary {
  background-color: var(--color-navy);
  color: var(--color-text-inverse);
}

.btn--primary:hover {
  background-color: var(--color-navy-deep);
  transform: translateY(-1px);
}

.btn--ghost {
  background-color: transparent;
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  font-weight: 400;
}

.btn--ghost:hover {
  color: var(--color-text-primary);
  border-color: var(--color-text-secondary);
}

.btn__arrow {
  font-size: 1rem;
  transition: transform var(--transition-base);
}

.btn:hover .btn__arrow {
  transform: translateX(3px);
}

/* ============================================
   Services
   ============================================ */
.services__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.service-card {
  padding: 2.5rem 2rem;
  background: var(--color-bg-white);
  border: 1px solid var(--color-border-light);
  border-radius: 4px;
  position: relative;
  transition: border-color var(--transition-base),
              box-shadow var(--transition-base);
}

.service-card:hover {
  border-color: var(--color-border);
  box-shadow: 0 4px 24px rgba(26, 26, 46, 0.05);
}

.service-card__accent {
  position: absolute;
  top: 0;
  left: 2rem;
  width: 32px;
  height: 3px;
  background: linear-gradient(90deg, var(--color-navy), var(--color-amber));
  border-radius: 0 0 2px 2px;
}

.service-card__number {
  font-family: var(--font-en);
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--color-text-tertiary);
  letter-spacing: 0.1em;
  margin-bottom: var(--space-md);
  display: block;
}

.service-card__title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--space-sm);
  letter-spacing: 0.03em;
}

.service-card__text {
  font-size: 0.875rem;
  line-height: 1.9;
  color: var(--color-text-secondary);
}

/* ============================================
   Philosophy
   ============================================ */
.philosophy__layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: var(--space-xl);
  align-items: start;
  max-width: 960px;
}

.philosophy__lead {
  font-size: clamp(1.25rem, 2.5vw, 1.625rem);
  font-weight: 500;
  line-height: 1.8;
  letter-spacing: 0.04em;
  color: var(--color-text-primary);
  margin-bottom: var(--space-lg);
}

.philosophy__body {
  font-size: 0.9375rem;
  line-height: 2.2;
  color: var(--color-text-secondary);
}

.philosophy__body p + p {
  margin-top: var(--space-md);
}

.philosophy__accent-line {
  width: 40px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-navy), var(--color-amber));
  margin-bottom: var(--space-lg);
  border-radius: 1px;
}

/* ============================================
   Company
   ============================================ */
.company__table {
  width: 100%;
  max-width: 720px;
}

.company__row {
  display: grid;
  grid-template-columns: 160px 1fr;
  border-bottom: 1px solid var(--color-border-light);
  padding: 1.25rem 0;
}

.company__row:first-child {
  border-top: 1px solid var(--color-border-light);
}

.company__label {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-text-tertiary);
  letter-spacing: 0.04em;
  padding-top: 0.1rem;
}

.company__value {
  font-size: 0.9375rem;
  color: var(--color-text-primary);
  line-height: 1.8;
}

/* ============================================
   Contact
   ============================================ */
.contact {
  padding: var(--space-3xl) 0;
}

.contact__inner {
  background: linear-gradient(135deg, var(--color-navy) 0%, var(--color-bg-dark) 100%);
  border-radius: 6px;
  padding: var(--space-2xl) var(--space-xl);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.contact__inner::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-amber), var(--color-amber-soft), transparent);
}

.contact__heading {
  font-size: clamp(1.25rem, 2.5vw, 1.625rem);
  font-weight: 600;
  color: var(--color-text-inverse);
  letter-spacing: 0.04em;
  margin-bottom: var(--space-sm);
}

.contact__text {
  font-size: 0.9375rem;
  color: rgba(255, 255, 255, 0.6);
  margin-bottom: var(--space-md);
  line-height: 1.7;
}

.contact__email {
  font-family: var(--font-en);
  font-size: 0.9375rem;
  font-weight: 400;
  color: rgba(255, 255, 255, 0.8);
  letter-spacing: 0.03em;
  margin-bottom: var(--space-md);
  display: block;
  transition: color var(--transition-base);
}

.contact__email:hover {
  color: var(--color-text-inverse);
}

.btn--inverse {
  background-color: var(--color-text-inverse);
  color: var(--color-navy);
  font-weight: 500;
}

.btn--inverse:hover {
  background-color: rgba(255, 255, 255, 0.9);
  transform: translateY(-1px);
}

/* ============================================
   Footer
   ============================================ */
.footer {
  background-color: var(--color-bg-dark);
  padding: var(--space-xl) 0 var(--space-lg);
}

.footer__inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--space-xl);
}

.footer__logo {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  transition: opacity var(--transition-base);
}

.footer__logo:hover {
  opacity: 0.7;
}

.footer__logo-mark {
  height: 30px;
  width: auto;
  opacity: 0.9;
}

.footer__logo-name {
  font-family: var(--font-en);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text-inverse);
  letter-spacing: 0.1em;
  line-height: 1;
}

.footer__nav {
  display: flex;
  gap: 1.75rem;
}

.footer__nav-link {
  font-size: 0.8125rem;
  color: rgba(255, 255, 255, 0.5);
  transition: color var(--transition-base);
  letter-spacing: 0.02em;
}

.footer__nav-link:hover {
  color: rgba(255, 255, 255, 0.85);
}

.footer__bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  padding-top: var(--space-md);
  text-align: center;
}

.footer__copyright {
  font-family: var(--font-en);
  font-size: 0.6875rem;
  color: rgba(255, 255, 255, 0.3);
  letter-spacing: 0.05em;
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 900px) {
  .services__grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .philosophy__layout {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .company__row {
    grid-template-columns: 120px 1fr;
  }

  .footer__inner {
    flex-direction: column;
    gap: var(--space-md);
  }

  .footer__nav {
    flex-wrap: wrap;
    gap: 1.25rem;
  }

  .hero__watermark {
    width: 320px;
    height: 320px;
    right: -10%;
  }
}

@media (max-width: 768px) {
  :root {
    --space-3xl: 5rem;
    --space-4xl: 6rem;
  }

  .header__nav {
    display: none;
  }

  .header__hamburger {
    display: flex;
  }

  .hero {
    min-height: 78vh;
  }

  .hero__content {
    padding: var(--space-2xl) 1.5rem;
  }

  .hero__watermark {
    display: none;
  }

  .hero__heading {
    font-size: 1.625rem;
    line-height: 1.7;
  }

  .contact__inner {
    padding: var(--space-xl) var(--space-md);
  }

  .container, .container--narrow {
    padding: 0 1.5rem;
  }
}

@media (max-width: 480px) {
  .hero__actions {
    flex-direction: column;
    width: 100%;
  }

  .hero__actions .btn {
    justify-content: center;
    width: 100%;
  }

  .company__row {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }

  .company__label {
    font-weight: 600;
    color: var(--color-text-primary);
    font-size: 0.75rem;
  }

  .header__logo-mark {
    height: 28px;
  }

  .header__logo-name {
    font-size: 0.9375rem;
  }
}