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

:root {
  --color-primary: #5F5F5F;
  --color-primary-soft: rgba(95, 95, 95, 0.08);
  --color-bg: #ffffff;
  --color-bg-alt: #f5f5f5;
  --color-text: #5F5F5F;
  --color-text-muted: #8a8a8a;
  --color-border: #e5e5e5;
  --font-sans: "M PLUS 1", sans-serif;
  --header-height: 72px;
  --max-width: 1080px;
  --ease: cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  letter-spacing: -0.01em;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 clamp(1.5rem, 5vw, 4rem);
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 var(--color-border);
}

.logo {
  display: inline-flex;
  align-items: center;
}

.logo img {
  height: clamp(22px, 3vw, 28px);
  width: auto;
  display: block;
}

.nav {
  display: flex;
  gap: clamp(1.5rem, 4vw, 2.5rem);
  list-style: none;
}

.nav a {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

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

.nav-toggle {
  display: none;
  width: 28px;
  height: 20px;
  flex-direction: column;
  justify-content: space-between;
  background: none;
  border: none;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--color-text);
}

.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: calc(var(--header-height) + 3rem) clamp(1.5rem, 5vw, 4rem) 4rem;
}

.hero-label {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: 1rem;
}

.hero-title {
  font-size: clamp(2.8rem, 9vw, 6.5rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.04em;
  margin-bottom: 1.5rem;
}

.hero-lead {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--color-text-muted);
  max-width: 36rem;
}

.section {
  padding: clamp(4.5rem, 10vw, 7rem) clamp(1.5rem, 5vw, 4rem);
  background: var(--color-bg);
  border-top: 1px solid var(--color-primary);
}

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-label {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: 0.75rem;
}

.display-md {
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 1.5rem;
}

.section-intro {
  color: var(--color-text-muted);
  margin-bottom: 2.5rem;
  max-width: 40rem;
}

.about-table {
  border-top: 1px solid var(--color-border);
}

.about-row {
  display: grid;
  grid-template-columns: 8rem 1fr;
  gap: 1.5rem;
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--color-border);
}

.about-row dt {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-muted);
}

.about-row dd {
  font-size: 1.05rem;
}

.group-card {
  display: block;
  background: #009CE1;
  border: 2px solid #009CE1;
  padding: clamp(2rem, 4vw, 3rem);
  transition: background 0.3s var(--ease), border-color 0.3s var(--ease);
}

.group-card:hover {
  background: #007bb5;
  border-color: #007bb5;
}

.group-logo {
  height: clamp(28px, 4vw, 36px);
  width: auto;
  display: block;
  margin-bottom: 1.25rem;
}

.group-desc {
  color: rgba(255, 255, 255, 0.92);
  margin-bottom: 1.5rem;
}

.group-link {
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: #fff;
}

.group-link::after {
  content: " →";
}

.contact-block {
  font-style: normal;
  font-size: 1.05rem;
  line-height: 1.9;
}

.contact-block a {
  color: var(--color-text);
}

.contact-block a:hover {
  text-decoration: underline;
}

.footer {
  background: var(--color-primary);
  color: #fff;
  text-align: center;
  padding: 3rem clamp(1.5rem, 5vw, 4rem) 2rem;
}

.footer-logo {
  display: inline-block;
  font-weight: 700;
  letter-spacing: 0.04em;
  margin-bottom: 1.25rem;
}

.footer-nav {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  list-style: none;
  margin-bottom: 2rem;
}

.footer-nav a {
  font-size: 0.8rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.85);
}

.footer-nav a:hover {
  color: #fff;
}

.footer-copy {
  font-size: 0.75rem;
  color: rgba(255, 255, 255, 0.55);
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.2);
}

@media (max-width: 640px) {
  .br-pc {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .nav {
    display: none;
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: #fff;
    flex-direction: column;
    align-items: center;
    padding: 2rem;
    gap: 1.5rem;
    border-bottom: 1px solid var(--color-border);
  }

  .nav.open {
    display: flex;
  }

  .about-row {
    grid-template-columns: 1fr;
    gap: 0.4rem;
  }
}