/* ===========================
   Artein Website - Global Styles
   Design: Modern Navy / Indigo 2026
=========================== */

@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@300;400;500;700&family=Inter:wght@300;400;500;600;700&display=swap');

/* ── CSS Variables ── */
:root {
  --color-navy:        #0F2557;
  --color-navy-mid:    #1A3A7A;
  --color-navy-light:  #2351A3;
  --color-accent:      #4A7FD4;
  --color-accent-glow: #6B9FE4;
  --color-white:       #FFFFFF;
  --color-off-white:   #F8FAFC;
  --color-surface:     #EEF2FF;
  --color-text:        #0F172A;
  --color-text-muted:  #475569;
  --color-border:      #CBD5E1;
  --color-border-light:#E2E8F0;

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

  --radius-sm:  6px;
  --radius-md:  12px;
  --radius-lg:  20px;
  --radius-xl:  32px;

  --shadow-sm:  0 1px 3px rgba(15,37,87,.08), 0 1px 2px rgba(15,37,87,.06);
  --shadow-md:  0 4px 16px rgba(15,37,87,.12), 0 2px 6px rgba(15,37,87,.08);
  --shadow-lg:  0 20px 60px rgba(15,37,87,.18), 0 8px 20px rgba(15,37,87,.1);

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

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-ja);
  color: var(--color-text);
  background: var(--color-white);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }

/* ── Typography ── */
.en { font-family: var(--font-en); }

h1, h2, h3, h4 {
  line-height: 1.3;
  letter-spacing: -0.01em;
}

/* ── Layout ── */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 100px 0;
}

.section-label {
  font-family: var(--font-en);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 16px;
}

.section-title {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: 20px;
}

.section-title span {
  font-family: var(--font-en);
  font-style: italic;
}

.section-lead {
  font-size: 17px;
  color: var(--color-text-muted);
  line-height: 1.85;
  max-width: 600px;
}

/* ── Navigation ── */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  transition: background var(--transition), box-shadow var(--transition);
  padding: 0;
}

.nav.scrolled {
  background: rgba(15, 37, 87, 0.96);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 rgba(255,255,255,0.08);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  padding: 0 40px;
  max-width: 1200px;
  margin: 0 auto;
}

.nav-logo {
  display: flex;
  flex-direction: column;
  line-height: 1;
}

.nav-logo-name {
  font-family: var(--font-en);
  font-size: 22px;
  font-weight: 700;
  color: var(--color-white);
  letter-spacing: 0.04em;
}

.nav-logo-sub {
  font-size: 10px;
  color: rgba(255,255,255,0.55);
  letter-spacing: 0.05em;
  margin-top: 2px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 40px;
}

.nav-links a {
  font-size: 14px;
  font-weight: 500;
  color: rgba(255,255,255,0.8);
  letter-spacing: 0.04em;
  transition: color var(--transition);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--color-accent-glow);
  transform: scaleX(0);
  transition: transform var(--transition);
}

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

.nav-links a:hover::after {
  transform: scaleX(1);
}

.nav-cta {
  padding: 10px 24px;
  background: var(--color-accent);
  color: var(--color-white) !important;
  border-radius: 100px;
  font-size: 13px !important;
  font-weight: 600 !important;
  transition: background var(--transition), transform var(--transition) !important;
}

.nav-cta::after { display: none !important; }

.nav-cta:hover {
  background: var(--color-accent-glow) !important;
  transform: translateY(-1px);
}

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-white);
  border-radius: 2px;
  transition: var(--transition);
}

.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ── Footer ── */
.footer {
  background: var(--color-navy);
  color: rgba(255,255,255,0.7);
  padding: 60px 0 32px;
}

.footer-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-logo-name {
  font-family: var(--font-en);
  font-size: 24px;
  font-weight: 700;
  color: var(--color-white);
  letter-spacing: 0.04em;
}

.footer-logo-sub {
  font-size: 11px;
  color: rgba(255,255,255,0.4);
  letter-spacing: 0.06em;
  margin-top: 4px;
}

.footer-tagline {
  font-size: 13px;
  color: rgba(255,255,255,0.5);
  margin-top: 16px;
  line-height: 1.7;
}

.footer-nav-title {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.4);
  margin-bottom: 16px;
}

.footer-nav-links {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-nav-links a {
  font-size: 14px;
  color: rgba(255,255,255,0.65);
  transition: color var(--transition);
}

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

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-copy {
  font-size: 12px;
  color: rgba(255,255,255,0.35);
  font-family: var(--font-en);
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 100px;
  font-size: 15px;
  font-weight: 600;
  font-family: var(--font-ja);
  transition: var(--transition);
  letter-spacing: 0.02em;
}

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

.btn-primary:hover {
  background: var(--color-surface);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(255,255,255,0.2);
}

.btn-outline {
  border: 1.5px solid rgba(255,255,255,0.4);
  color: var(--color-white);
}

.btn-outline:hover {
  border-color: var(--color-white);
  background: rgba(255,255,255,0.08);
  transform: translateY(-2px);
}

.btn-navy {
  background: var(--color-navy);
  color: var(--color-white);
}

.btn-navy:hover {
  background: var(--color-navy-mid);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-arrow::after {
  content: '→';
  font-family: var(--font-en);
  transition: transform var(--transition);
}

.btn-arrow:hover::after {
  transform: translateX(4px);
}

/* ── Scroll Animation ── */
.reveal {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ── Page Hero (inner pages) ── */
.page-hero {
  background: linear-gradient(135deg, var(--color-navy) 0%, var(--color-navy-mid) 100%);
  padding: 160px 0 80px;
  position: relative;
  overflow: hidden;
}

.page-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 70% 50%, rgba(74,127,212,0.2) 0%, transparent 60%);
}

.page-hero-label {
  font-family: var(--font-en);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-accent-glow);
  margin-bottom: 16px;
}

.page-hero-title {
  font-size: clamp(32px, 5vw, 52px);
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 16px;
}

.page-hero-sub {
  font-size: 16px;
  color: rgba(255,255,255,0.6);
}

/* ── Utility ── */
.text-center { text-align: center; }
.text-navy { color: var(--color-navy); }
.bg-surface { background: var(--color-off-white); }
.divider {
  width: 48px;
  height: 3px;
  background: var(--color-accent);
  border-radius: 2px;
  margin-bottom: 32px;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .nav-inner { padding: 0 20px; }

  .nav-links {
    display: none;
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--color-navy);
    flex-direction: column;
    gap: 0;
    padding: 16px 0 24px;
    border-top: 1px solid rgba(255,255,255,0.1);
  }

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

  .nav-links a {
    padding: 16px 24px;
    font-size: 15px;
    width: 100%;
    border-bottom: 1px solid rgba(255,255,255,0.06);
  }

  .nav-links a::after { display: none; }

  .nav-cta {
    border-radius: 0 !important;
    padding: 16px 24px !important;
    background: transparent !important;
    color: var(--color-accent-glow) !important;
    font-size: 15px !important;
  }

  .nav-cta:hover { transform: none; }

  .nav-toggle { display: flex; }

  .section { padding: 72px 0; }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }
}