:root {
  --fg: #1a1a1a;
  --bg: #fafafa;
  --muted: #666;
  --border: #d0d0d0;
  --accent: #2a5db0;
  --error-bg: #fde8e8;
  --error-fg: #a02020;
  --success-bg: #e8f5e8;
  --success-fg: #1a5a1a;
  --mono: ui-monospace, "SF Mono", Consolas, "Liberation Mono", monospace;
}
* { box-sizing: border-box; }
html { min-height: 100%; }
body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Microsoft YaHei", sans-serif;
  color: var(--fg);
  background: var(--bg);
  margin: 0;
  line-height: 1.5;
  font-size: 16px;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}
main { max-width: 960px; margin: 0 auto; padding: 2rem 1.25rem 4rem; flex: 1 0 auto; width: 100%; }

/* ---- Header / nav bar ---- */
header { border-bottom: 1px solid var(--border); flex-shrink: 0; }
.header-inner {
  max-width: 960px; margin: 0 auto; padding: 0.75rem 1.25rem;
  display: flex; align-items: center; justify-content: space-between; gap: 1rem; flex-wrap: wrap;
}
.brand { font-size: 1.15rem; font-weight: 700; color: var(--fg); text-decoration: none; }
.nav-links { display: flex; align-items: center; gap: 1rem; font-size: 0.9rem; flex-wrap: wrap; }
.nav-links a { color: var(--accent); text-decoration: none; }
.nav-links a:hover { text-decoration: underline; }
.github-link { display: inline-flex; align-items: center; color: var(--muted); }
.github-link:hover { color: var(--fg); }

h1, h2, h3 { line-height: 1.25; }
h2 { margin-top: 2rem; }
section { margin: 1.5rem 0; }
label { display: block; font-weight: 500; margin: 0.5rem 0 0.15rem; }
input[type=text], input[type=email], input[type=number] {
  display: block; width: 100%; max-width: 360px; padding: 0.45rem 0.55rem;
  border: 1px solid var(--border); border-radius: 4px; font-size: 1rem; font-family: inherit;
}
input[type=text].code { font-family: var(--mono); letter-spacing: 0.05em; text-transform: uppercase; }
button {
  background: var(--accent); color: #fff; border: none; border-radius: 4px;
  padding: 0.5rem 1.1rem; font-size: 1rem; cursor: pointer; margin-top: 0.75rem;
}
button:hover { filter: brightness(1.1); }
form { margin: 0.5rem 0; }
.hint { color: var(--muted); font-size: 0.85rem; margin-top: 0.25rem; }
.error {
  background: var(--error-bg); color: var(--error-fg); border: 1px solid var(--error-fg);
  padding: 0.6rem 0.8rem; border-radius: 4px; margin: 1rem 0;
}
.success {
  background: var(--success-bg); color: var(--success-fg); border: 1px solid var(--success-fg);
  padding: 0.6rem 0.8rem; border-radius: 4px; margin: 1rem 0;
}
table { width: 100%; border-collapse: collapse; margin: 0.75rem 0; font-size: 0.92rem; }
th, td { text-align: left; padding: 0.4rem 0.55rem; border-bottom: 1px solid var(--border); vertical-align: top; }
th { background: #f0f0f0; font-weight: 600; }
td.code, td.mono { font-family: var(--mono); font-size: 0.85rem; }
td.status-unused { color: var(--muted); }
td.status-redeemed { color: var(--success-fg); font-weight: 500; }
.pager { margin: 1rem 0; display: flex; gap: 0.5rem; align-items: center; }
.pager a { padding: 0.25rem 0.6rem; border: 1px solid var(--border); border-radius: 4px; text-decoration: none; color: var(--accent); }
.pager a.disabled { color: var(--muted); pointer-events: none; opacity: 0.5; }
.codelist {
  background: #fff; border: 1px solid var(--border); border-radius: 4px;
  padding: 0.75rem; font-family: var(--mono); font-size: 0.9rem;
  white-space: pre-wrap; word-break: break-all; user-select: all;
}
.tag-pill {
  display: inline-block; background: #eef; color: var(--accent);
  padding: 0.05rem 0.4rem; border-radius: 3px; font-size: 0.8rem; margin-right: 0.2rem;
}
.muted { color: var(--muted); }

/* ---- Footer ---- */
footer { padding: 1rem 1.25rem; border-top: 1px solid var(--border); color: var(--muted); font-size: 0.85rem; flex-shrink: 0; }
.footer-row { max-width: 960px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.alt-link { margin: 0.75rem 0 0; font-size: 0.9rem; }
.alt-link a { color: var(--accent); }

/* ---- Landing: cards (shared with sponsor page) ---- */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1rem; margin: 1.5rem 0; }
.card { display: block; padding: 1.25rem; border: 1px solid var(--border); border-radius: 6px;
        text-decoration: none; color: var(--fg); background: #fff; transition: border-color .15s, box-shadow .15s; }
.card:hover { border-color: var(--accent); box-shadow: 0 2px 8px rgba(0,0,0,.06); }
.card h3 { margin: 0 0 0.35rem; font-size: 1.1rem; }
.card p { margin: 0 0 0.75rem; color: var(--muted); font-size: 0.92rem; }
.card .card-arrow { color: var(--accent); font-weight: 500; }

/* ---- Landing: hero ---- */
.hero { text-align: center; padding: 3rem 1rem 2rem; }
.hero h1 { font-size: 2.5rem; margin: 0 0 0.5rem; }
.hero-tagline { font-size: 1.2rem; color: var(--muted); margin: 0 0 1.5rem; }
.hero-cta { display: flex; gap: 0.75rem; justify-content: center; flex-wrap: wrap; }
.btn { display: inline-block; padding: 0.6rem 1.5rem; border-radius: 4px; text-decoration: none; font-size: 1rem; font-weight: 500; cursor: pointer; }
.btn-primary { background: var(--accent); color: #fff; border: 1px solid var(--accent); }
.btn-primary:hover { filter: brightness(1.1); }
.btn-secondary { background: transparent; color: var(--accent); border: 1px solid var(--accent); }
.btn-secondary:hover { background: var(--accent); color: #fff; }

/* ---- Landing: features ---- */
.features { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1.5rem; margin: 1.5rem 0; }
.feature { padding: 1rem; }
.feature h3 { margin: 0 0 0.35rem; }
.feature p { margin: 0; color: var(--muted); font-size: 0.92rem; }

/* ---- Landing: screenshots ---- */
.screenshots { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 1rem; margin: 1.5rem 0; }
.screenshot-placeholder {
  aspect-ratio: 16 / 10; background: #f0f0f0; border: 1px solid var(--border); border-radius: 6px;
  display: flex; align-items: center; justify-content: center; color: var(--muted); font-size: 0.9rem;
}

/* ---- Markdown content (about / sponsor body text) ---- */
.lang-content h1 { font-size: 1.6rem; margin: 0 0 0.75rem; }
.lang-content h2 { font-size: 1.3rem; margin: 1.5rem 0 0.5rem; }
.lang-content p { margin: 0.5rem 0; }
.lang-content ul, .lang-content ol { margin: 0.5rem 0; padding-left: 1.5rem; }
.lang-content li { margin: 0.25rem 0; }
.lang-content a { color: var(--accent); }
.lang-content code { font-family: var(--mono); font-size: 0.9em; background: #f0f0f0; padding: 0.1em 0.3em; border-radius: 3px; }
.lang-content pre { background: #f0f0f0; padding: 0.75rem; border-radius: 4px; overflow-x: auto; }
.lang-content pre code { background: none; padding: 0; }
.lang-content blockquote { border-left: 3px solid var(--border); margin: 0.5rem 0; padding-left: 1rem; color: var(--muted); }
.lang-content img { max-width: 100%; height: auto; }
.lang-content :last-child { margin-bottom: 0; }

/* ---- Language toggle ---- */
.lang-toggle { display: inline-flex; gap: 0.25rem; }
.lang-toggle button {
  background: transparent; color: var(--muted); border: 1px solid var(--border);
  padding: 0.15rem 0.5rem; font-size: 0.8rem; cursor: pointer; border-radius: 3px; margin: 0;
}
.lang-toggle button:hover { filter: none; border-color: var(--accent); color: var(--accent); }
.lang-toggle button.active { background: var(--accent); color: #fff; border-color: var(--accent); }