:root {
  --bg: #0b0b0c;
  --bg-alt: #141416;
  --fg: #f3f3f4;
  --fg-muted: #a8a8ad;
  --accent: #6ee7c7;
  --accent-contrast: #0b0b0c;
  --temp-accent: #ffb020;
  --temp-accent-contrast: #1a1200;
  --border: #232326;
  --header-bg: rgba(11, 11, 12, 0.9);
  --max-width: 1080px;
}

/* Light theme is opt-in only (via the toggle), never automatic —
   default is always dark regardless of prefers-color-scheme. */
:root[data-theme="light"] {
  --bg: #ffffff;
  --bg-alt: #f2f2f4;
  --fg: #17171a;
  --fg-muted: #5b5b62;
  --accent: #0e8f68;
  --accent-contrast: #ffffff;
  --temp-accent: #d98a00;
  --temp-accent-contrast: #fffaf0;
  --border: #e2e2e6;
  --header-bg: rgba(255, 255, 255, 0.9);
}

* {
  box-sizing: border-box;
}

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

body {
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

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

a:hover {
  text-decoration: underline;
}

.site-header {
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: var(--header-bg);
  backdrop-filter: blur(6px);
  z-index: 10;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  padding-bottom: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--fg);
}

.brand:hover {
  text-decoration: none;
}

.brand-logo {
  height: 32px;
  width: auto;
}

.brand-name {
  font-weight: 600;
  font-size: 1.1rem;
  letter-spacing: 0.02em;
}

.site-nav {
  display: flex;
  gap: 24px;
}

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

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

.temp-cta {
  background: var(--temp-accent);
  color: var(--temp-accent-contrast) !important;
  font-weight: 700;
  padding: 6px 14px;
  border-radius: 999px;
}

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

.hero {
  padding: 96px 0 72px;
  text-align: center;
}

.hero h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  margin: 0 0 16px;
}

.tagline {
  color: var(--fg-muted);
  font-size: 1.15rem;
  max-width: 640px;
  margin: 0 auto 32px;
}

.cta {
  display: inline-block;
  background: var(--accent);
  color: var(--accent-contrast);
  font-weight: 600;
  padding: 12px 28px;
  border-radius: 6px;
}

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

.section {
  padding: 64px 0;
  border-top: 1px solid var(--border);
}

.section-alt {
  background: var(--bg-alt);
}

.section h2 {
  font-size: 1.75rem;
  margin: 0 0 24px;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
}

.card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px;
  background: var(--bg);
}

.card h3 {
  margin: 0 0 8px;
  font-size: 1.1rem;
}

.card p {
  margin: 0;
  color: var(--fg-muted);
}

.link-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.link-list li {
  margin-bottom: 8px;
  font-size: 1.05rem;
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 0;
  color: var(--fg-muted);
  font-size: 0.9rem;
  text-align: center;
}

@media (max-width: 640px) {
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .site-nav {
    gap: 16px;
    flex-wrap: wrap;
  }
}

.notice {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px 20px;
  color: var(--fg-muted);
}

.notice a {
  color: var(--accent);
}

.checklist {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.checklist li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  color: var(--fg-muted);
}

.checklist input[type="checkbox"] {
  margin-top: 4px;
  flex-shrink: 0;
}

.footer-links {
  margin-top: 4px;
}

.footer-links a {
  color: var(--fg-muted);
  font-size: 0.85rem;
}

body,
.site-header,
.card {
  transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--fg-muted);
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
  padding: 6px 10px;
}

.theme-toggle:hover {
  color: var(--fg);
}