/* ── Design tokens ─────────────────────────── */
:root {
  --bg: #fafafa;
  --bg-card: #ffffff;
  --bg-gradient: linear-gradient(135deg, #d8dcf0 0%, #f4d4dc 100%);
  --ink: #1a1a2e;
  --ink-soft: #4a4a5e;
  --ink-muted: #888899;
  --accent: #5b67c4;
  --accent-hover: #4a55b0;
  --border: #e5e5ea;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --max-width: 1100px;
  --section-py: 80px;
  --section-py-mobile: 48px;
  --radius: 8px;
  --radius-lg: 16px;
}

/* ── Reset ─────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}
img, picture { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); text-decoration: underline; }
button { font: inherit; cursor: pointer; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 2px; }

/* ── Motion preferences ────────────────────── */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}

/* ── Layout helpers ────────────────────────── */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }
.section { padding: var(--section-py) 0; }
@media (max-width: 768px) {
  .section { padding: var(--section-py-mobile) 0; }
}
section[id] { scroll-margin-top: 72px; }

/* ── Headings ──────────────────────────────── */
h1, h2, h3 { color: var(--ink); line-height: 1.2; font-weight: 700; text-wrap: balance; }
h1 { font-size: clamp(2rem, 5vw, 3rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2.25rem); margin-bottom: 16px; }
h3 { font-size: 1.125rem; margin-bottom: 8px; }
p { color: var(--ink-soft); }
.subtitle { color: var(--ink-muted); font-size: 1.125rem; margin-bottom: 32px; }
.eyebrow { color: var(--ink-muted); text-transform: uppercase; font-size: 0.75rem; letter-spacing: 1px; font-weight: 600; }

/* ── Buttons ───────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 24px; border-radius: var(--radius);
  font-weight: 600; font-size: 1rem; border: 1px solid transparent;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
  text-decoration: none;
}
.btn-primary { background: var(--ink); color: #fff; }
.btn-primary:hover { background: #000; color: #fff; text-decoration: none; }
.btn-secondary { background: transparent; color: var(--ink); border-color: var(--border); }
.btn-secondary:hover { border-color: var(--ink); color: var(--ink); text-decoration: none; }

/* ── Nav ───────────────────────────────────── */
.site-nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(250, 250, 250, 0.85);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 60px;
}
.nav-logo { color: var(--ink); font-weight: 700; font-size: 1.125rem; text-decoration: none; }
.nav-logo:hover { text-decoration: none; }
.nav-links { display: flex; align-items: center; gap: 24px; }
.nav-links a:not(.btn) { color: var(--ink-soft); font-size: 0.95rem; }
.nav-links a:not(.btn):hover { color: var(--ink); text-decoration: none; }
.btn-sm { padding: 8px 16px; font-size: 0.9rem; }
@media (max-width: 600px) {
  .nav-links a:not(.btn) { display: none; }  /* mobile: 只留 logo + download */
}

/* ── Hero ──────────────────────────────────── */
.hero { background: var(--bg-gradient); padding-top: 64px; padding-bottom: 64px; }
.hero-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 48px; align-items: center;
}
.hero-text h1 { margin-bottom: 16px; }
.hero-ctas { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; margin-bottom: 16px; }
.hero-meta { font-size: 0.875rem; color: var(--ink-muted); }
.hero-image img { border-radius: var(--radius-lg); box-shadow: 0 20px 60px rgba(26, 26, 46, 0.12); }
@media (max-width: 768px) {
  .hero-grid { grid-template-columns: 1fr; gap: 32px; }
  .hero-image { order: -1; }  /* 圖在文字上方 */
}

/* ── Demo ──────────────────────────────────── */
.demo { background: var(--bg); }
.demo-grid {
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 16px; margin-top: 24px;
}
.demo-tile {
  background-color: #2a2a3e;
  background-image: linear-gradient(45deg, #e0e0e0 25%, transparent 25%),
                    linear-gradient(-45deg, #e0e0e0 25%, transparent 25%),
                    linear-gradient(45deg, transparent 75%, #e0e0e0 75%),
                    linear-gradient(-45deg, transparent 75%, #e0e0e0 75%);
  background-size: 16px 16px;
  background-position: 0 0, 0 8px, 8px -8px, -8px 0px;
  border-radius: var(--radius);
  overflow: hidden;
  position: relative;
  transition: transform 0.2s;
}
.demo-tile img { width: 100%; height: auto; display: block; }
.demo-tile.is-dark-loaded { background-image: none; background-color: #1a1a2e; }
.demo-tile figcaption {
  position: absolute; bottom: 8px; left: 8px;
  background: rgba(0, 0, 0, 0.6); color: #fff;
  padding: 4px 8px; border-radius: 4px;
  font-size: 0.75rem; font-weight: 600;
}
.demo-tile:hover { transform: translateY(-2px); }
.demo-caption {
  margin-top: 24px; text-align: center;
  color: var(--ink-muted); font-size: 0.95rem;
}
@media (max-width: 768px) {
  .demo-grid { grid-template-columns: repeat(2, 1fr); }
}

/* ── Features ──────────────────────────────── */
.features { background: var(--bg-card); }
.features-grid {
  display: grid; grid-template-columns: repeat(2, 1fr);
  gap: 32px; margin-top: 16px;
}
.feature-icon { font-size: 2rem; margin-bottom: 12px; }
.feature h3 { margin-bottom: 8px; }
.feature p { font-size: 0.95rem; }
@media (max-width: 768px) {
  .features-grid { grid-template-columns: 1fr; gap: 24px; }
}

/* ── Audience ──────────────────────────────── */
.audience { background: var(--bg); padding-top: 48px; padding-bottom: 48px; }
.audience-inner { text-align: center; }
.audience-text { font-size: 1.05rem; color: var(--ink-soft); }
.tag {
  display: inline-block;
  background: var(--bg-card); color: var(--ink);
  padding: 4px 10px; border-radius: 100px;
  font-size: 0.875rem; font-weight: 600;
  border: 1px solid var(--border);
  margin: 0 2px;
}

/* ── Pricing ───────────────────────────────── */
.pricing { background: var(--bg-gradient); text-align: center; }
.pricing-inner { max-width: 640px; margin: 0 auto; }
.pricing h2 { margin-bottom: 12px; }
.btn-lg { padding: 16px 32px; font-size: 1.125rem; margin-top: 16px; }
.pricing-meta { font-size: 0.875rem; color: var(--ink-muted); margin-top: 16px; }

/* ── 中文段 ────────────────────────────────── */
.zh { background: var(--bg-card); }
.zh-inner { max-width: 720px; margin: 0 auto; }
.zh-lead { font-size: 1.0625rem; margin-bottom: 24px; line-height: 1.7; }
.zh-list { list-style: none; padding: 0; margin-bottom: 24px; }
.zh-list li {
  padding: 12px 0; border-bottom: 1px solid var(--border);
  color: var(--ink-soft); line-height: 1.6;
}
.zh-list li:last-child { border-bottom: none; }
.zh-list strong { color: var(--ink); font-weight: 600; }
.zh-meta { font-size: 0.95rem; color: var(--ink-muted); margin-bottom: 24px; }
.zh-ctas { display: flex; flex-wrap: wrap; gap: 12px; }

/* ── FAQ ───────────────────────────────────── */
.faq { background: var(--bg); }
.faq-inner { max-width: 720px; margin: 0 auto; }
.faq h2 { margin-bottom: 24px; }
.faq details {
  padding: 16px 0; border-bottom: 1px solid var(--border);
}
.faq summary {
  font-weight: 600; color: var(--ink);
  cursor: pointer; list-style: none;
  display: flex; align-items: center; justify-content: space-between;
  padding: 4px 0;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+"; color: var(--ink-muted);
  font-size: 1.25rem; line-height: 1; margin-left: 16px;
  transition: transform 0.15s;
}
.faq details[open] summary::after { content: "−"; }
.faq details p { margin-top: 12px; color: var(--ink-soft); line-height: 1.6; }

/* ── Footer ────────────────────────────────── */
.site-footer { background: var(--bg-card); border-top: 1px solid var(--border); padding: 32px 0; }
.footer-inner {
  display: flex; justify-content: space-between; align-items: center;
  flex-wrap: wrap; gap: 16px;
  font-size: 0.875rem;
}
.footer-brand { display: flex; gap: 12px; align-items: center; }
.footer-logo { font-weight: 700; color: var(--ink); }
.footer-copy { color: var(--ink-muted); }
.footer-links { display: flex; flex-wrap: wrap; gap: 16px 24px; }
.footer-links a { color: var(--ink-soft); }
.footer-links a:hover { color: var(--ink); }

/* ── Legal pages ───────────────────────────── */
.legal-inner { max-width: 720px; margin: 0 auto; }
.legal h1 { margin-bottom: 8px; }
.legal h2 { font-size: 1.25rem; margin-top: 32px; margin-bottom: 12px; }
.legal-meta { color: var(--ink-muted); font-size: 0.875rem; margin-bottom: 24px; }
.legal p, .legal ul { color: var(--ink-soft); margin-bottom: 16px; line-height: 1.7; }
.legal ul { padding-left: 24px; }
.legal code { background: var(--bg-card); padding: 2px 6px; border-radius: 4px; font-size: 0.9em; border: 1px solid var(--border); }