:root {
  --bg: #16161e;
  --bg-alt: #1a1b26;
  --surface: #1f2233;
  --border: #2c3049;
  --text: #e0e0e8;
  --text-muted: #9aa0b5;
  --accent: #7aa2f7;
  --accent-strong: #89b4fa;
  --radius: 12px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Navbar ---------- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

.brand-icon {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--text);
}

.lang-toggle {
  background: var(--surface);
  color: var(--accent);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 4px 10px;
  font-size: 0.85rem;
  cursor: pointer;
  transition: background 0.2s;
}

.lang-toggle:hover {
  background: var(--border);
}

/* ---------- Hero ---------- */
.hero {
  padding: 140px 0 80px;
  text-align: center;
  background:
    radial-gradient(ellipse 70% 50% at 50% -10%, rgba(122, 162, 247, 0.15), transparent),
    var(--bg-alt);
}

.hero-title {
  font-size: clamp(3rem, 8vw, 5rem);
  font-weight: 800;
  letter-spacing: -0.02em;
}

.hero-subtitle {
  display: block;
  font-size: clamp(1.2rem, 3vw, 1.6rem);
  font-weight: 500;
  color: var(--accent);
  margin-top: 8px;
}

.hero-tagline {
  max-width: 560px;
  margin: 20px auto 32px;
  font-size: 1.1rem;
  color: var(--text-muted);
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.hero-screenshot {
  margin-top: 56px;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: var(--radius);
  text-decoration: none;
  font-size: 1rem;
  font-weight: 600;
  transition: transform 0.15s, box-shadow 0.15s, background 0.15s;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn-primary {
  background: var(--accent);
  color: #10121a;
  box-shadow: 0 4px 20px rgba(122, 162, 247, 0.35);
}

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

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

.btn-secondary:hover {
  border-color: var(--accent);
}

.btn-lg {
  padding: 14px 36px;
  font-size: 1.05rem;
}

/* ---------- Sections ---------- */
.section {
  padding: 88px 0;
}

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

.section-title {
  font-size: 2.2rem;
  text-align: center;
  font-weight: 700;
}

.section-desc {
  text-align: center;
  color: var(--text-muted);
  margin: 12px 0 48px;
  font-size: 1.05rem;
}

/* ---------- Features ---------- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  transition: transform 0.2s, border-color 0.2s;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 14px;
}

.feature-card h3 {
  font-size: 1.15rem;
  margin-bottom: 8px;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* ---------- Screenshots ---------- */
.screenshot-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
}

.placeholder-screenshot {
  display: flex;
  align-items: center;
  justify-content: center;
  background: repeating-linear-gradient(
    45deg,
    var(--surface),
    var(--surface) 12px,
    color-mix(in srgb, var(--surface) 92%, white) 12px,
    color-mix(in srgb, var(--surface) 92%, white) 24px
  );
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  color: var(--text-muted);
  font-size: 0.95rem;
  aspect-ratio: 16 / 9;
}

.placeholder-screenshot.tall {
  aspect-ratio: 4 / 3;
}

/* ---------- Download ---------- */
.download-section {
  background:
    radial-gradient(ellipse 60% 60% at 50% 110%, rgba(122, 162, 247, 0.12), transparent),
    var(--bg-alt);
}

.download-buttons {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.download-note {
  text-align: center;
  margin-top: 24px;
  color: var(--text-muted);
  font-size: 0.95rem;
}

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

.download-note a:hover {
  text-decoration: underline;
}

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* ---------- Reveal animation ---------- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* ---------- Mobile ---------- */
@media (max-width: 640px) {
  .nav-links a {
    display: none;
  }
  .hero {
    padding-top: 100px;
  }
}