/* オンライン教育業界サイト - EduTech Insight */
:root {
  --primary: #0f766e;
  --primary-dark: #115e59;
  --accent: #22c55e;
  --bg: #0b1220;
  --panel: #0f172a;
  --text: #e5e7eb;
  --muted: #94a3b8;
  --shadow: 0 12px 30px rgba(0,0,0,.25);
  --gradient: radial-gradient(1200px 600px at 10% -10%, rgba(34,197,94,.15), transparent 40%),
              radial-gradient(1000px 500px at 90% -20%, rgba(15,118,110,.25), transparent 40%),
              linear-gradient(180deg, #0b1220 0%, #0a0f1c 100%);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  font-family: 'Segoe UI', 'Hiragino Sans', 'Noto Sans JP', system-ui, -apple-system, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.8;
}

header {
  position: fixed; inset: 0 0 auto 0; z-index: 1000;
  backdrop-filter: blur(10px);
  background: rgba(10,15,28,.6);
  border-bottom: 1px solid rgba(255,255,255,.06);
}
nav { max-width: 1200px; margin: 0 auto; padding: 0.8rem 1.5rem; display: flex; align-items: center; justify-content: space-between; }
.logo { font-weight: 700; letter-spacing: .3px; font-size: 1.2rem; color: #fff; }
.nav-menu { list-style: none; display: flex; gap: 1.4rem; }
.nav-menu a { color: var(--text); text-decoration: none; opacity: .9; position: relative; }
.nav-menu a:hover { color: #fff; }
.nav-menu a::after { content: ''; position: absolute; left: 0; bottom: -6px; width: 0; height: 2px; background: var(--accent); transition: width .25s; }
.nav-menu a:hover::after { width: 100%; }
.mobile-menu-btn { display: none; background: none; border: none; cursor: pointer; padding: .4rem; }
.hamburger-line { width: 24px; height: 3px; background: var(--text); display: block; margin: 3px 0; transition: .2s; }

main { margin-top: 72px; }

.hero {
  background: var(--gradient);
  padding: 6rem 1.5rem 4rem;
  text-align: center;
  position: relative;
}
.hero-content { max-width: 900px; margin: 0 auto; }
.hero h1 { font-size: clamp(1.8rem, 2.8vw, 3rem); margin-bottom: .6rem; }
.hero-subtitle { color: var(--muted); margin-bottom: 1.4rem; }
.cta-button { display: inline-block; padding: .7rem 1.1rem; background: linear-gradient(90deg, var(--primary), var(--accent)); color: #fff; border-radius: 10px; text-decoration: none; box-shadow: var(--shadow); }

.hero-media { margin-top: 1rem; }
.hero-media img { width: 100%; max-width: 1024px; display: block; margin: 0.6rem auto 0; border-radius: 12px; box-shadow: var(--shadow); }

.section { padding: 3rem 1.5rem; max-width: 1160px; margin: 0 auto; }
.section-header { margin-bottom: 1.2rem; }
.section-title { font-size: 1.5rem; margin-bottom: .2rem; }
.section-subtitle { color: var(--muted); }

.grid.two { display: grid; gap: 1.2rem; grid-template-columns: 1fr; }
@media (min-width: 880px) { .grid.two { grid-template-columns: 1fr 1fr; } }

.checklist { list-style: none; }
.checklist li { margin: .4rem 0; padding-left: 1.3rem; position: relative; }
.checklist li::before { content: '✔'; color: var(--accent); position: absolute; left: 0; }

.links { list-style: none; }
.links li { margin: .3rem 0; }
.links a { color: #93c5fd; text-decoration: none; }
.links a:hover { text-decoration: underline; }

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 1rem; }
.card { background: linear-gradient(180deg, rgba(255,255,255,.06), rgba(255,255,255,.03)); border: 1px solid rgba(255,255,255,.07); border-radius: 14px; padding: 1rem; box-shadow: var(--shadow); }
.card h3 { margin-bottom: .4rem; }

.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: .8rem; list-style: none; }
.stat-number { font-weight: 700; font-size: 1.4rem; color: #86efac; display: block; }
.stat-label { color: var(--muted); }

.list-tiles { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: .8rem; }
.tile { display: block; text-decoration: none; color: var(--text); background: linear-gradient(180deg, rgba(15,118,110,.25), rgba(34,197,94,.15)); border: 1px solid rgba(255,255,255,.06); padding: 1rem; border-radius: 12px; box-shadow: var(--shadow); }
.tile:hover { border-color: rgba(34,197,94,.45); }

.news-list { list-style: none; }
.news-list li { padding: .6rem .8rem; background: rgba(255,255,255,.04); border: 1px solid rgba(255,255,255,.06); margin: .4rem 0; border-radius: 10px; }
.badge { background: rgba(34,197,94,.15); color: #bbf7d0; border: 1px solid rgba(34,197,94,.4); padding: .1rem .5rem; border-radius: 6px; margin-right: .5rem; font-size: .8rem; }

footer { padding: 2rem 1.5rem; color: var(--muted); border-top: 1px solid rgba(255,255,255,.06); background: rgba(10,15,28,.6); text-align: center; }

.footer-links { display: flex; flex-wrap: wrap; justify-content: center; gap: 1.5rem; margin-bottom: 1rem; }
.footer-links a { color: var(--text); text-decoration: none; opacity: .85; transition: opacity .25s, color .25s; }
.footer-links a:hover { color: var(--accent); opacity: 1; }

/* Responsive menu */
@media (max-width: 820px) {
  .nav-menu { display: none; position: absolute; top: 56px; right: 12px; background: rgba(10,15,28,.95); border: 1px solid rgba(255,255,255,.08); border-radius: 10px; padding: .6rem .8rem; flex-direction: column; }
  .nav-menu.mobile-open { display: flex; }
  .mobile-menu-btn { display: block; }

  .footer-links { gap: 1rem; font-size: 0.9rem; }
}