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

:root {
  --bg: #0d0d0d;
  --text: #e6e6e6;
  --text-muted: #999;
  --accent: #22c55e;
  --accent-hover: #16a34a;
  --card-bad-bg: rgba(220, 38, 38, 0.08);
  --card-bad-border: rgba(220, 38, 38, 0.35);
  --card-good-bg: rgba(34, 197, 94, 0.08);
  --card-good-border: rgba(34, 197, 94, 0.35);
  --code-bg: rgba(255, 255, 255, 0.06);
  --border: rgba(255, 255, 255, 0.06);
  --btn-text: #0d0d0d;
  --max-width: 42rem;
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme]) {
    --bg: #fafafa;
    --text: #1a1a1a;
    --text-muted: #666;
    --accent: #16a34a;
    --accent-hover: #15803d;
    --card-bad-bg: rgba(220, 38, 38, 0.08);
    --card-bad-border: rgba(220, 38, 38, 0.4);
    --card-good-bg: rgba(34, 197, 94, 0.1);
    --card-good-border: rgba(34, 197, 94, 0.4);
    --code-bg: rgba(0, 0, 0, 0.06);
    --border: rgba(0, 0, 0, 0.08);
    --btn-text: #fff;
  }
}

[data-theme="light"] {
  --bg: #fafafa;
  --text: #1a1a1a;
  --text-muted: #666;
  --accent: #16a34a;
  --accent-hover: #15803d;
  --card-bad-bg: rgba(220, 38, 38, 0.08);
  --card-bad-border: rgba(220, 38, 38, 0.4);
  --card-good-bg: rgba(34, 197, 94, 0.1);
  --card-good-border: rgba(34, 197, 94, 0.4);
  --code-bg: rgba(0, 0, 0, 0.06);
  --border: rgba(0, 0, 0, 0.08);
  --btn-text: #fff;
}

body {
  margin: 0;
  font-family: "Figtree", system-ui, sans-serif;
  font-size: 1.0625rem;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-github-header {
  padding: 0.4rem 0.75rem;
  font-size: 0.875rem;
}

.logo {
  font-weight: 700;
  font-size: 1.125rem;
  letter-spacing: -0.02em;
}

main {
  padding: 2.5rem 1.5rem 3rem;
  max-width: var(--max-width);
  margin: 0 auto;
}

.hero {
  margin-bottom: 3rem;
}

.hero-tagline {
  font-size: clamp(1.5rem, 3.5vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--accent);
  margin: 0 0 0.5rem;
  line-height: 1.2;
}

.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.03em;
  margin: 0 0 1rem;
}
.hero-authority {
  color: var(--text-muted);
  font-weight: 500;
}

.hero-authority-list {
  list-style: none;
  margin: 0 0 1.5rem;
  padding: 0;
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: 500;
}

.hero-authority-list li {
  position: relative;
  padding-left: 1.25rem;
  margin-bottom: 0.35rem;
}

.hero-authority-list li:last-child {
  margin-bottom: 0;
}

.hero-authority-list li::before {
  content: "▶︎ ";
  position: absolute;
  left: 0;
}

.hero-sub {
  color: var(--text-muted);
  margin: 0 0 1.5rem;
  font-size: 1rem;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  margin: 0 0 0.5rem;
}

.btn-github {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  font-size: 1rem;
  font-weight: 600;
  color: #0d0d0d;
  background: #fff;
  border: 1px solid rgba(255, 255, 255, 0.4);
  border-radius: 8px;
  text-decoration: none;
  white-space: nowrap;
  transition:
    background 0.2s,
    border-color 0.2s;
}

.btn-github:hover {
  background: rgba(255, 255, 255, 0.9);
}

.btn-github:active {
  transform: scale(0.98);
}

.btn-github svg {
  flex-shrink: 0;
}

[data-theme="light"] .btn-github {
  border-color: rgba(0, 0, 0, 0.15);
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme]) .btn-github {
    border-color: rgba(0, 0, 0, 0.15);
  }
}

.btn-download {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background: var(--accent);
  color: var(--btn-text);
  font-weight: 600;
  font-size: 1rem;
  text-decoration: none;
  border-radius: 8px;
  transition:
    background 0.2s,
    color 0.2s;
}

.btn-download:hover {
  background: var(--accent-hover);
}

.hero-note {
  font-size: 0.9375rem;
  color: var(--text-muted);
  margin: 0;
}

.who-for {
  margin-bottom: 3rem;
}

.who-for h2 {
  font-size: 1.375rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 0 0 1rem;
}

.who-for-list {
  margin: 0;
  padding-left: 1.25rem;
}

.who-for-list li {
  margin-bottom: 0.5rem;
  color: var(--text-muted);
}

.who-for-list li:last-child {
  margin-bottom: 0;
}

.problem {
  margin-bottom: 3rem;
}

.problem-image {
  margin: 1.5rem 0;
}

.problem-image img {
  display: block;
  max-width: 100%;
  height: auto;
  border-radius: 10px;
  border: 1px solid var(--border);
}

.problem-image figcaption {
  margin-top: 0.5rem;
  font-size: 0.9375rem;
  color: var(--text-muted);
}

.problem h2,
.whats-inside h2,
.how-to-use h2 {
  font-size: 1.375rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 0 0 1rem;
}

.problem > p,
.philosophy {
  color: var(--text-muted);
  margin: 1rem 0 1.25rem;
}

.philosophy {
  margin-top: 1.25rem;
}

.before-after {
  display: grid;
  gap: 1rem;
  margin-top: 1.25rem;
}

.card {
  padding: 1.25rem;
  border-radius: 10px;
  border: 1px solid;
}

.card strong {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 0.9375rem;
}

.card p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.55;
}

.card-bad {
  background: var(--card-bad-bg);
  border-color: var(--card-bad-border);
}

.card-bad strong {
  color: #f87171;
}

.card-good {
  background: var(--card-good-bg);
  border-color: var(--card-good-border);
}

.card-good strong {
  color: var(--accent);
}

.whats-inside {
  margin-bottom: 3rem;
}

.rules-list {
  margin: 0;
  padding-left: 1.25rem;
}

.rules-list li {
  margin-bottom: 0.75rem;
}

.rules-list li:last-child {
  margin-bottom: 0;
}

.how-to-use {
  margin-bottom: 2.5rem;
}

.how-to-use-intro {
  margin: 0 0 1rem;
  font-weight: 500;
}

.use-list {
  margin: 0 0 1rem;
  padding-left: 1.25rem;
}

.use-list li {
  margin-bottom: 0.5rem;
}

code {
  font-size: 0.875em;
  padding: 0.15em 0.4em;
  background: var(--code-bg);
  border-radius: 4px;
}

.how-to-use p {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--text-muted);
}

.cta-bottom {
  text-align: center;
  padding: 1rem 0;
}

.cta-bottom .btn-download {
  font-size: 1rem;
}

.site-footer {
  padding: 1.5rem;
  border-top: 1px solid var(--border);
  text-align: center;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 1rem;
}

.footer-license {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.theme-toggle {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.4rem 0.75rem;
  font-size: 0.875rem;
  font-family: inherit;
  color: var(--text-muted);
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  transition:
    color 0.2s,
    background 0.2s,
    border-color 0.2s;
}

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