:root {
  --color-bg: #ffffff;
  --color-text: #141414;
  --color-text-muted: #6f6f6f;
  --color-border: #ececec;
  --color-accent: #111111;
  --color-link: #111111;
  --color-link-hover: #666666;

  --font-en: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-jp: "Noto Sans JP", "Yu Gothic", "YuGothic", sans-serif;
  --font-base: var(--font-jp), var(--font-en);

  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 2.25rem;
  --space-lg: 5rem;
  --space-xl: 9rem;

  --max-width: 680px;
  --max-width-wide: 960px;
}

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

html,
body {
  margin: 0;
  padding: 0;
}

body {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-base);
  font-size: 17px;
  line-height: 1.9;
  letter-spacing: 0.015em;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

main {
  display: block;
}

a {
  color: var(--color-link);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.24em;
  transition: color 0.2s ease, opacity 0.2s ease;
}

a:hover {
  color: var(--color-link-hover);
  opacity: 0.72;
}

a.external::after {
  content: " ↗";
  display: inline-block;
  margin-left: 0.2em;
}

p {
  margin: 0 0 var(--space-sm);
}

h1,
h2,
h3 {
  line-height: 1.55;
  letter-spacing: 0.02em;
  margin: 0 0 0.9rem;
  font-weight: 500;
}

h1 {
  font-size: clamp(1.72rem, 3vw, 2.18rem);
  letter-spacing: 0.015em;
}

h2 {
  font-size: clamp(1.03rem, 1.65vw, 1.12rem);
  margin-top: var(--space-md);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-family: var(--font-en);
  color: #232323;
}

h3 {
  font-size: 1rem;
  font-family: var(--font-en);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

ul {
  margin: 0 0 var(--space-sm);
  padding-left: 1.2rem;
}

li {
  margin-bottom: 0.3rem;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.6rem;
}

.container--wide {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 1.6rem;
}

.hero {
  padding: calc(var(--space-xl) + 0.5rem) 0 var(--space-lg);
  text-align: center;
}

.hero__greeting {
  font-family: var(--font-en);
  font-size: clamp(2rem, 5.1vw, 3.2rem);
  line-height: 1.2;
  letter-spacing: 0.01em;
  margin-bottom: 1.2rem;
  font-weight: 500;
}

.hero__name {
  margin-bottom: 0.4rem;
}

.hero__tagline {
  color: var(--color-text-muted);
  font-size: 1rem;
  margin-left: auto;
  margin-right: auto;
}

.intro,
.layers,
.platforms {
  margin-bottom: var(--space-lg);
}

.layer {
  border-top: none;
  padding-top: 0;
  margin-top: calc(var(--space-lg) * 0.72);
}

.layer__sub {
  margin-top: calc(var(--space-md) + 0.4rem);
}

.page-header {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-md) 1.6rem 0;
}

.page-header__back {
  color: var(--color-text-muted);
  text-decoration: none;
}

.page-header__back:hover {
  text-decoration: underline;
}

.page-title {
  margin-top: 1.2rem;
  margin-bottom: calc(var(--space-md) - 0.4rem);
}

.tagline {
  color: var(--color-text-muted);
  margin-bottom: calc(var(--space-md) + 0.2rem);
}

.bio,
.layers-detail,
.vision,
.location,
.not-doing,
.contact-method,
.contact-note {
  margin-bottom: var(--space-lg);
}

.note {
  color: var(--color-text-muted);
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-sm);
}

.footer {
  border-top: none;
  margin-top: calc(var(--space-xl) - 1rem);
  padding: var(--space-md) 0 var(--space-lg);
}

.footer__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.6rem;
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

.footer__nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm) var(--space-md);
}

.footer__nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  gap: 0.85rem;
}

.platforms ul {
  list-style: none;
  padding-left: 0;
}

.platforms li {
  margin-bottom: 0.58rem;
}

.footer a {
  color: inherit;
}

@media (min-width: 768px) {
  .hero {
    padding-top: calc(var(--space-xl) + var(--space-lg));
  }

  .platforms {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: calc(var(--space-lg) + 0.2rem);
  }
}