/* ========================================================================
   AT-amustak Shared Styles
   - 共通の変数 / リセット / ヘッダー / ナビ / ページヘッダー / セクション / フッター
   - カラーは CLAUDE.md のロゴ準拠パレットに統一
   ======================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@300;400;500;600;700;900&family=Barlow:wght@400;500;600;700;800;900&display=swap');

:root {
  /* ── Brand Colors ── */
  --primary: #0d2240;
  --primary-mid: #143565;
  --accent-dark: #0b6fdb;
  --accent: #1a8cff;
  --accent-light: #5eaaff;
  --silver: #8a9bb5;
  --silver-light: #c5cfde;

  /* ── Surfaces & Text ── */
  --bg: #f3f5f9;
  --bg-card: #ffffff;
  --bg-card2: #f8fafd;
  --bg-dark: #0d2240;
  --ink: #0d2240;
  --ink2: #333b50;
  --ink3: #6b7690;
  --border: #d5dae6;
  --border2: #e3e7ef;
  --chrome: #ffffff;

  /* ── Aliases (legacy refs) ── */
  --metal-blue: #0b6fdb;
  --metal-blue3: #1a8cff;
  --blue-glow: rgba(26, 140, 255, 0.18);

  /* ── Layout ── */
  --max-w: 1100px;
  --radius: 6px;

  /* ── Fonts ── */
  --font-en: 'Barlow', sans-serif;
  --font-head: 'Barlow', 'Noto Sans JP', sans-serif;
  --font-jp: 'Noto Sans JP', sans-serif;

  /* ── Gradients ── */
  --grad-main: linear-gradient(135deg, #0d2240 0%, #143565 30%, #0b6fdb 100%);
  --grad-hero: linear-gradient(135deg, #0d2240 0%, #143565 30%, #0b6fdb 100%);
  --grad-blue: linear-gradient(135deg, #0b6fdb 0%, #1a8cff 100%);
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-jp);
  color: var(--ink2);
  background: #ffffff;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent-dark); }

/* ===========================================================
   SITE HEADER (logo on left, horizontal nav on right)
   =========================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #ffffff;
  border-bottom: 3px solid var(--primary);
  box-shadow: 0 4px 14px rgba(13, 34, 64, 0.06);
}
.site-header-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 28px;
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  gap: 32px;
  position: relative;
  min-height: 160px;
}
.header-logo {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  color: var(--primary);
  padding: 4px 0;
}
.header-logo img {
  height: 152px;
  width: auto;
}
.header-nav {
  display: flex;
  align-items: center;
  gap: 38px;
}
.header-nav a {
  position: relative;
  color: var(--primary);
  text-decoration: none;
  font-size: 1rem;
  font-weight: 700;
  padding: 10px 0;
  transition: color 0.2s;
}
.header-nav a::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s;
}
.header-nav a:hover { color: var(--accent-dark); }
.header-nav a:hover::after,
.header-nav a.active::after { transform: scaleX(1); }
.header-nav a.active { color: var(--accent-dark); }

.hamburger {
  display: none;
  background: transparent;
  border: none;
  width: 44px;
  height: 44px;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  cursor: pointer;
  align-self: center;
  margin-left: auto;
}
.hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--primary);
  transition: all 0.2s;
}

/* ===========================================================
   PAGE HEADER (gradient hero strip with breadcrumb)
   =========================================================== */
.page-header {
  background: var(--grad-main);
  color: #ffffff;
  position: relative;
  overflow: hidden;
}
.page-header::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(rgba(255, 255, 255, 0.08) 1px, transparent 1px);
  background-size: 24px 24px;
  opacity: 0.5;
}
.page-header-inner {
  position: relative;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 64px 28px 56px;
}
.page-title-en {
  font-family: var(--font-en);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--silver-light);
  margin-bottom: 8px;
}
.page-title {
  font-size: 2rem;
  font-weight: 900;
  line-height: 1.3;
  margin-bottom: 18px;
}
.breadcrumb {
  font-size: 0.82rem;
  color: var(--silver-light);
}
.breadcrumb a {
  color: #ffffff;
  text-decoration: none;
  opacity: 0.85;
}
.breadcrumb a:hover { opacity: 1; text-decoration: underline; }

/* ===========================================================
   SECTION (generic content block)
   =========================================================== */
.section { padding: 72px 0; }
.section-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 28px;
}
.sec-head {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 32px;
  padding-bottom: 14px;
  border-bottom: 3px solid var(--primary);
}
.sec-title {
  font-family: var(--font-en);
  font-size: 1.4rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  color: var(--primary);
}
.sec-title-en {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--ink3);
}

/* ===========================================================
   FOOTER
   =========================================================== */
footer {
  background: var(--primary);
  color: var(--silver-light);
  margin-top: 0;
}
.footer-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 28px;
}
.footer-bottom {
  text-align: center;
  font-size: 0.76rem;
  color: var(--silver);
  letter-spacing: 0.04em;
}

/* ===========================================================
   SCROLL-TO-TOP BUTTON
   =========================================================== */
.scroll-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--primary);
  color: #ffffff;
  border: 2px solid var(--accent);
  font-size: 1.1rem;
  font-weight: 800;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition: all 0.25s;
  z-index: 99;
  box-shadow: 0 4px 16px rgba(13, 34, 64, 0.25);
}
.scroll-top.show {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
.scroll-top:hover {
  background: var(--accent-dark);
  transform: translateY(-2px);
}

/* ===========================================================
   RESPONSIVE
   =========================================================== */
@media (max-width: 800px) {
  .site-header-inner { padding: 0 20px; gap: 12px; min-height: 88px; }
  .header-logo img { height: 80px; }
  .hamburger { display: flex; }
  .header-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: #ffffff;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.06);
    gap: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }
  .header-nav.open { max-height: 500px; }
  .header-nav a {
    padding: 14px 24px;
    border-top: 1px solid var(--border2);
    width: 100%;
  }
  .header-nav a::after { display: none; }

  .page-header-inner { padding: 44px 24px 36px; }
  .page-title { font-size: 1.5rem; }

  .section { padding: 48px 0; }
  .section-inner { padding: 0 20px; }

  .footer-inner { padding: 40px 24px 24px; }
}