:root {
  --color-bg: #ffffff;
  --color-surface: #ffffff;
  --color-surface-2: #f8fafc;
  --color-text: #111827;
  --color-muted: #6b7280;
  --color-accent: #2563eb; /* blue-600 */
  --color-accent-2: #60a5fa; /* blue-400 */
  --shadow-sm: 0 1px 2px rgba(0,0,0,.1);
  --shadow-md: 0 8px 24px rgba(0,0,0,.25);
  --radius: 12px;
  --container: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Noto Sans JP, Hiragino Kaku Gothic ProN, Meiryo, sans-serif;
  line-height: 1.7;
  color: var(--color-text);
  background: radial-gradient(1200px 600px at 10% -10%, rgba(37,99,235,0.08), transparent 60%),
              radial-gradient(1000px 600px at 90% 10%, rgba(96,165,250,0.08), transparent 60%),
              var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }

.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 20px; }
.section { padding: 72px 0; }
.section.alt { background: linear-gradient(0deg, rgba(2,6,23,0.02), rgba(2,6,23,0.02)), var(--color-surface-2); }
.section-title { font-size: 28px; margin: 0 0 24px; letter-spacing: .02em; }

.skip-link {
  position: absolute; left: -9999px; top: auto; width: 1px; height: 1px; overflow: hidden;
}
.skip-link:focus { position: static; width: auto; height: auto; padding: 8px 12px; background: #fff; color: #111; }

/* Header */
.site-header { position: sticky; top: 0; z-index: 40; background: rgba(255, 255, 255, .85); backdrop-filter: blur(8px); border-bottom: 1px solid rgba(17,24,39,.06); }
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo img { filter: none; }
.site-nav ul { display: flex; gap: 20px; list-style: none; margin: 0; padding: 0; }
.site-nav a { color: var(--color-muted); padding: 8px 10px; border-radius: 8px; }
.site-nav a:hover, .site-nav a:focus { color: var(--color-accent); background: rgba(37,99,235,.08); }

.nav-toggle { display: none; width: 40px; height: 40px; border: 1px solid rgba(17,24,39,.12); background: transparent; border-radius: 10px; color: #111; }
.nav-toggle-bar { display: block; width: 20px; height: 2px; background: #111; margin: 0 auto; position: relative; }
.nav-toggle-bar::before, .nav-toggle-bar::after { content: ""; position: absolute; left: 0; width: 20px; height: 2px; background: #111; }
.nav-toggle-bar::before { top: -6px; }
.nav-toggle-bar::after { top: 6px; }

/* Hero */
.hero { padding: 96px 0 72px; background: linear-gradient(180deg, rgba(37,99,235,.05), rgba(255,255,255,0) 40%), transparent; }
.hero-content { text-align: center; max-width: 760px; margin: 0 auto; }
.hero h1 { font-size: 36px; line-height: 1.2; margin: 0 0 12px; }
.hero p { color: var(--color-muted); margin: 0 0 24px; }
.hero-cta { display: inline-flex; gap: 12px; flex-wrap: wrap; }

/* Cards */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.card {
  background: linear-gradient(180deg, rgba(2,6,23,.02), rgba(255,255,255,0)), var(--color-surface);
  border: 1px solid rgba(17,24,39,.08);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow-sm);
}
.card h3 { margin: 0 0 8px; font-size: 18px; }
.card p { margin: 0; color: var(--color-muted); }

/* About */
.about dl { display: grid; grid-template-columns: 160px 1fr; gap: 12px 20px; margin: 0; }
.about dt { color: var(--color-muted); }
.about dd { margin: 0; }
.about > dl > div { display: contents; }

/* Contact */
.contact { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; align-items: start; }
.contact-list { list-style: none; margin: 0 0 8px; padding: 0; color: var(--color-muted); }
.contact-form { background: var(--color-surface); border: 1px solid rgba(17,24,39,.08); border-radius: var(--radius); padding: 16px; }
.contact-form label { display: grid; gap: 6px; margin: 0 0 12px; font-size: 14px; }
.contact-form input, .contact-form select, .contact-form textarea {
  width: 100%; padding: 10px 12px; color: #111827; background: #ffffff; border: 1px solid #e5e7eb; border-radius: 10px; outline: none;
}
.contact-form input:focus, .contact-form select:focus, .contact-form textarea:focus { border-color: var(--color-accent); box-shadow: 0 0 0 3px rgba(37,99,235,.2); }
.form-note { color: var(--color-muted); font-size: 12px; margin: 8px 0 0; }

/* Buttons */
.button { display: inline-block; padding: 10px 16px; border-radius: 12px; border: 1px solid rgba(17,24,39,.12); }
.button.primary { background: linear-gradient(180deg, #3b82f6, #2563eb); border-color: rgba(37,99,235,.6); color: #ffffff; }
.button.primary:hover { box-shadow: 0 10px 22px rgba(37,99,235,.25); }
.button.ghost { background: transparent; color: var(--color-accent); }
.button.full { width: 100%; text-align: center; }
.button[disabled] { opacity: .6; cursor: not-allowed; }

/* Footer */
.site-footer { padding: 28px 0; border-top: 1px solid rgba(17,24,39,.06); background: #ffffff; }
.site-footer p { margin: 0; color: var(--color-muted); }

/* Header shadow on scroll */
.site-header.is-scrolled { box-shadow: 0 4px 20px rgba(0,0,0,.12); }

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

/* Form status */
.form-status { font-size: 14px; margin-top: 8px; padding: 10px 12px; border-radius: 10px; border: 1px solid transparent; }
.form-status.is-success { color: #166534; background: #ecfdf5; border-color: #bbf7d0; }
.form-status.is-error { color: #991b1b; background: #fef2f2; border-color: #fecaca; }

/* Video section */
.video-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.video-item video { width: min(100%, 480px); height: auto; display: block; margin: 0 auto; border-radius: 10px; border: 1px solid rgba(17,24,39,.08); background: #000; aspect-ratio: 16 / 9; object-fit: contain; }
.video-item h3 { margin: 0 0 8px; }
.video-item .button { margin-top: 12px; }
.video-player { width: 100%; max-width: 480px; margin: 0 auto; }

@media (max-width: 960px) {
  .video-grid { grid-template-columns: 1fr; }
  .video-player { width: 100%; max-width: none; }
  .video-item video { width: 100%; }
}

@media (max-width: 960px) {
  .cards { grid-template-columns: 1fr 1fr; }
  .contact { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .nav-toggle { display: inline-flex; align-items: center; justify-content: center; }
  .site-nav { position: fixed; inset: 64px 12px auto; background: var(--color-surface); border: 1px solid rgba(17,24,39,.08); border-radius: var(--radius); padding: 12px; transform: translateY(-16px); opacity: 0; pointer-events: none; transition: .2s ease; }
  .site-nav ul { flex-direction: column; gap: 8px; }
  .site-nav.is-open { transform: translateY(0); opacity: 1; pointer-events: auto; }
  .cards { grid-template-columns: 1fr; }
  .about dl { grid-template-columns: 1fr; }
}