/* Colors follow tailwind.css (app theme). */
:root {
  color-scheme: light;
  --background: #f4f4f5;
  --surface: #ffffff;
  --foreground: #1e293b;
  --foreground-secondary: #334155;
  --foreground-muted: #5b6b80;
  --border: #e2e8f0;
  --accent: #f97316;
  --accent-subtle: #fff7ed;
  --accent-soft: #ffedd5;
  --accent-strong: #9a3412;
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --background: #0f172a;
    --surface: #1e293b;
    --foreground: #f1f5f9;
    --foreground-secondary: #cbd5e1;
    --foreground-muted: #94a3b8;
    --border: #334155;
    --accent-subtle: #431407;
    --accent-soft: #7c2d12;
    --accent-strong: #fdba74;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--background);
  color: var(--foreground);
  font-family:
    -apple-system, BlinkMacSystemFont, "SF Pro Text", "Hiragino Sans",
    "Hiragino Kaku Gothic ProN", "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--foreground);
  text-decoration-color: var(--foreground-muted);
  text-underline-offset: 3px;
}

.wrap {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 16px;
}

/* Header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 1;
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--background) 85%, transparent);
  backdrop-filter: saturate(180%) blur(16px);
  -webkit-backdrop-filter: saturate(180%) blur(16px);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  gap: 16px;
  height: 56px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-right: auto;
  color: var(--foreground);
  font-weight: 700;
  letter-spacing: -0.01em;
  text-decoration: none;
}

.brand-mark {
  display: block;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  box-shadow: 0 0 0 1px rgb(15 23 42 / 0.08);
}

.nav {
  display: flex;
  gap: 4px;
}

.nav a {
  padding: 6px 10px;
  color: var(--foreground-muted);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
}

.nav a[aria-current="page"] {
  color: var(--foreground);
  text-decoration: underline;
  text-decoration-thickness: 1.5px;
  text-underline-offset: 6px;
}

/* Language switch */

.lang {
  display: flex;
  padding: 2px;
  border: 1px solid var(--border);
  border-radius: 8px;
}

.lang button {
  padding: 2px 10px;
  border: 0;
  border-radius: 6px;
  background: transparent;
  color: var(--foreground-muted);
  font: inherit;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

.lang button[aria-pressed="true"] {
  background: var(--foreground);
  color: var(--surface);
}

html[lang="en"] [lang="ja"],
html[lang="ja"] [lang="en"] {
  display: none;
}

/* Hero */

.hero {
  padding: 56px 0 32px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--foreground-muted);
  font-size: 14px;
  font-weight: 600;
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 6vw, 2.75rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.lead {
  margin: 16px 0 0;
  color: var(--foreground-secondary);
  font-size: 1.125rem;
}

.meta {
  margin: 12px 0 0;
  color: var(--foreground-muted);
  font-size: 14px;
}

/* Summary tiles */

.tiles {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 0 0 32px;
  padding: 0;
  list-style: none;
}

.tile {
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface);
}

.tile-icon {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  margin-bottom: 10px;
  border-radius: 8px;
  background: var(--background);
  color: var(--foreground);
}

.tile-title {
  display: block;
  font-weight: 700;
  line-height: 1.4;
}

.tile-text {
  display: block;
  margin-top: 2px;
  color: var(--foreground-secondary);
  font-size: 14px;
  line-height: 1.5;
}

@media (max-width: 560px) {
  .tiles {
    grid-template-columns: 1fr;
  }
}

/* Sections */

.card {
  margin: 0 0 12px;
  padding: 24px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface);
}

.card h2 {
  margin: 0 0 8px;
  font-size: 1.125rem;
  line-height: 1.4;
}

.card p {
  margin: 0;
  color: var(--foreground-secondary);
}

.card p + p {
  margin-top: 12px;
}

.section-title {
  margin: 40px 0 12px;
  font-size: 1.25rem;
}

/* Contact */

.contact {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.button {
  display: inline-block;
  padding: 12px 20px;
  border-radius: 8px;
  background: var(--foreground);
  color: var(--surface);
  font-weight: 700;
  text-decoration: none;
}

/* FAQ */

details {
  border-top: 1px solid var(--border);
}

details:last-of-type {
  border-bottom: 1px solid var(--border);
}

summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 0;
  font-weight: 700;
  cursor: pointer;
  list-style: none;
}

summary::-webkit-details-marker {
  display: none;
}

summary::after {
  content: "+";
  color: var(--foreground-muted);
  font-size: 1.25rem;
  font-weight: 400;
}

details[open] summary::after {
  content: "−";
}

details p {
  margin: 0;
  padding: 0 0 20px;
  color: var(--foreground-secondary);
}

/* Footer */

.site-footer {
  margin-top: 56px;
  padding: 24px 0 48px;
  border-top: 1px solid var(--border);
  color: var(--foreground-muted);
  font-size: 14px;
}

.site-footer .wrap {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px;
}

.site-footer a {
  color: inherit;
}

.nav a,
.lang button {
  white-space: nowrap;
}

@media (max-width: 560px) {
  .site-header .wrap {
    flex-wrap: wrap;
    row-gap: 0;
    height: auto;
    padding-top: 10px;
    padding-bottom: 8px;
  }

  .nav {
    order: 1;
    width: 100%;
    margin: 8px 0 0 -10px;
  }
}