/* =====================================================
   style.css — 全ページ共通スタイル
   education.qumcum.com
   ===================================================== */

/* ===== RESET & BASE ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: 'Noto Sans JP', sans-serif;
  color: #1E2A3B;
  background: #fff;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

/* ===== LAYOUT ===== */
.container { max-width: 1080px; margin: 0 auto; padding: 0 24px; }
.container--narrow { max-width: 720px; margin: 0 auto; padding: 0 24px; }

/* ===== SECTION 共通 ===== */
.section { padding: 96px 0; }
.section--alt { background: #F7F9FC; }

.section-label {
  display: inline-block;
  font-family: 'Outfit', sans-serif;
  font-size: 11px; font-weight: 700;
  letter-spacing: 0.15em; text-transform: uppercase;
  color: #1A56A4; margin-bottom: 12px;
}
.section-title {
  font-size: clamp(22px, 3.2vw, 32px);
  font-weight: 700; line-height: 1.4;
  color: #1E2A3B; margin-bottom: 16px;
  letter-spacing: -0.01em;
}
.section-lead {
  font-size: 15px; color: #4A5568;
  line-height: 1.9; max-width: 640px;
}
.section-divider {
  width: 36px; height: 2px;
  background: #1A56A4; margin: 16px 0 32px;
}

/* ===== HEADER / NAV ===== */
.header {
  position: sticky; top: 0; z-index: 100;
  background: #fff; border-bottom: 1px solid #E2E8F0;
}
.nav {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px; max-width: 1080px; margin: 0 auto; padding: 0 24px;
}
.logo-img { height: 34px; width: auto; }
.nav-menu { display: flex; align-items: center; gap: 24px; }
.nav-menu a { font-size: 13px; font-weight: 500; color: #4A5568; transition: color 0.2s; }
.nav-menu a:hover { color: #1A56A4; }
.nav-menu .nav-contact {
  background: #1A56A4; color: #fff;
  padding: 8px 18px; border-radius: 4px;
  font-size: 13px; font-weight: 500; transition: background 0.2s;
}
.nav-menu .nav-contact:hover { background: #1443A0; color: #fff; }
.nav-menu .nav-robot {
  background: #000; color: #C9A84C;
  padding: 8px 18px; border-radius: 4px;
  font-size: 13px; font-weight: 500; transition: background 0.2s;
}
.nav-menu .nav-robot:hover { background: #222; color: #C9A84C; }
.hamburger {
  display: none; flex-direction: column; gap: 5px;
  background: none; border: none; cursor: pointer; padding: 4px;
}
.hamburger span { display: block; width: 24px; height: 2px; background: #1E2A3B; transition: all 0.3s; }
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 12px 24px; border-radius: 4px;
  font-size: 14px; font-weight: 500;
  transition: all 0.2s; cursor: pointer; border: none;
}
.btn--primary { background: #1A56A4; color: #fff; }
.btn--primary:hover { background: #1443A0; }
.btn--outline { background: transparent; color: #1A56A4; border: 1px solid #1A56A4; }
.btn--outline:hover { background: #EBF4FF; }

/* ===== FOOTER ===== */
.footer { background: #1E2A3B; color: #A0AEC0; padding: 48px 0 32px; }
.footer-inner { display: grid; grid-template-columns: 1fr 2fr; gap: 48px; margin-bottom: 40px; }
.footer-brand img { height: 30px; margin-bottom: 16px; }
.footer-brand p { font-size: 12px; line-height: 1.9; color: #718096; }
.footer-links { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; }
.footer-links-group h4 { font-size: 11px; font-weight: 700; letter-spacing: 0.08em; color: #CBD5E0; margin-bottom: 12px; }
.footer-links-group li { margin-bottom: 8px; }
.footer-links-group a { font-size: 12px; color: #718096; transition: color 0.2s; }
.footer-links-group a:hover { color: #A0AEC0; }
.footer-bottom {
  border-top: 1px solid #2D3748; padding-top: 24px;
  display: flex; justify-content: space-between; align-items: center;
  font-size: 12px; color: #4A5568; flex-wrap: wrap; gap: 8px;
}
.footer-social { display: flex; gap: 16px; }
.footer-social a { font-size: 12px; color: #4A5568; transition: color 0.2s; }
.footer-social a:hover { color: #718096; }

/* ===== BACK TO TOP ===== */
.back-to-top {
  position: fixed; bottom: 24px; right: 24px;
  width: 44px; height: 44px; background: #1A56A4;
  border: none; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; cursor: pointer; opacity: 0;
  pointer-events: none; transition: opacity 0.3s, background 0.2s;
  z-index: 50; color: #fff;
  box-shadow: 0 4px 12px rgba(26,86,164,0.3);
}
.back-to-top.visible { opacity: 1; pointer-events: auto; }
.back-to-top:hover { background: #1443A0; }

/* ===== RESPONSIVE — 共通 ===== */
@media (max-width: 768px) {
  .section { padding: 64px 0; }

  /* ハンバーガーメニュー */
  .hamburger { display: flex; }
  .nav-menu {
    display: none; position: fixed; top: 64px; left: 0; right: 0;
    background: #fff; flex-direction: column; padding: 16px;
    gap: 4px; border-top: 1px solid #E2E8F0;
    box-shadow: 0 8px 24px rgba(0,0,0,0.1);
  }
  .nav-menu.open { display: flex; }
  .nav-menu a { display: block; padding: 12px 16px; border-radius: 4px; }
  .nav-menu a:hover { background: #F7F9FC; }
  .nav-menu .nav-contact { text-align: center; margin-top: 8px; }
  .nav-menu .nav-robot { text-align: center; margin-top: 8px; }

  /* フッター */
  .footer-inner { grid-template-columns: 1fr; gap: 32px; }
  .footer-links { grid-template-columns: 1fr 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
}
@media (max-width: 480px) {
  .footer-links { grid-template-columns: 1fr; }
}