:root {
  color-scheme: light dark;

  --bg: #fafaf9;
  --bg-elevated: #ffffff;
  --text: #1c1917;
  --text-muted: #57534e;
  --text-faint: #78716c;
  --border: #e7e5e4;
  --accent: #ea580c;
  --accent-text: #ffffff;
  --focus: #ea580c;

  --max-width: 720px;
  --nav-height: 64px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0c0a09;
    --bg-elevated: #17140f;
    --text: #fafaf9;
    --text-muted: #a8a29e;
    --text-faint: #78716c;
    --border: #292524;
    --accent: #fb923c;
    --accent-text: #1c1917;
    --focus: #fb923c;
  }
}

* {
  box-sizing: border-box;
}

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", "Meiryo", sans-serif;
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

/* ---------- Header / Nav ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.nav {
  max-width: var(--max-width);
  margin: 0 auto;
  height: var(--nav-height);
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: 0.01em;
  color: var(--text);
}

.nav-brand:hover {
  text-decoration: none;
  opacity: 0.8;
}

.nav-links {
  display: flex;
  gap: 24px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.nav-links a:hover,
.nav-links a[aria-current="page"] {
  color: var(--text);
  text-decoration: none;
}

.nav-links a[aria-current="page"] {
  position: relative;
}

.nav-links a[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -6px;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 10px;
  color: var(--text);
  font-size: 1rem;
  cursor: pointer;
}

@media (max-width: 560px) {
  .nav-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--bg-elevated);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    gap: 0;
    padding: 8px 20px;
    display: none;
  }

  .nav-links.is-open {
    display: flex;
  }

  .nav-links li {
    border-top: 1px solid var(--border);
  }

  .nav-links li:first-child {
    border-top: none;
  }

  .nav-links a {
    display: block;
    padding: 12px 0;
  }

  .nav-links a[aria-current="page"]::after {
    display: none;
  }
}

/* ---------- Main content ---------- */

main {
  flex: 1;
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  padding: 56px 20px 80px;
}

.badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 999px;
  padding: 4px 14px;
  margin-bottom: 24px;
}

h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 0 0 16px;
}

h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 40px 0 12px;
}

p {
  color: var(--text-muted);
  margin: 0 0 16px;
}

.lead {
  font-size: 1.1rem;
  color: var(--text);
}

.card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  margin-top: 24px;
}

.card + .card {
  margin-top: 16px;
}

.contact-row {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.email-box {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.95rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 14px;
  color: var(--text);
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--accent);
  color: var(--accent-text);
  border: none;
  border-radius: 8px;
  padding: 9px 16px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
}

.button:hover {
  opacity: 0.9;
  text-decoration: none;
}

.button-ghost {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

.copy-feedback {
  font-size: 0.85rem;
  color: var(--text-faint);
  min-height: 1.2em;
}

.timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 2px solid var(--border);
}

.timeline li {
  position: relative;
  padding: 0 0 20px 24px;
  color: var(--text-muted);
}

.timeline li::before {
  content: "";
  position: absolute;
  left: -6px;
  top: 4px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--border);
}

.timeline li.is-current::before {
  background: var(--accent);
}

.timeline li.is-current {
  color: var(--text);
  font-weight: 600;
}

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 20px;
}

.site-footer p {
  max-width: var(--max-width);
  margin: 0 auto;
  font-size: 0.85rem;
  color: var(--text-faint);
  text-align: center;
}

/* ---------- Fade-in ---------- */

.fade-in {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.fade-in.is-visible {
  opacity: 1;
  transform: none;
}