:root {
  --bg: #090a0f;
  --card-bg: rgba(255, 255, 255, 0.04);
  --card-border: rgba(255, 255, 255, 0.08);
  --card-hover-border: rgba(255, 255, 255, 0.16);
  --text: #f3f4f6;
  --text-muted: #9ca3af;
  --accent: #3b82f6;
  --accent-glow: rgba(59, 130, 246, 0.2);
  --code-bg: rgba(0, 0, 0, 0.5);
  --radius: 14px;
}

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

/* Multi-language display control via CSS */
html[lang="en"] .lang-zh {
  display: none !important;
}
html[lang="zh"] .lang-en {
  display: none !important;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
  padding: 0 1.25rem 4rem;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 860px;
  margin: 0 auto;
}

/* Top bar & Language switcher */
.top-bar {
  display: flex;
  justify-content: flex-end;
  padding-top: 1.25rem;
}

.lang-switcher {
  display: inline-flex;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--card-border);
  border-radius: 9999px;
  padding: 3px;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.lang-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  padding: 0.35rem 0.95rem;
  font-size: 0.85rem;
  font-weight: 500;
  border-radius: 9999px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.lang-btn.active {
  background: #2563eb;
  color: #fff;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.4);
}

.lang-btn:hover:not(.active) {
  color: var(--text);
}

header {
  padding: 3rem 0 2rem;
  text-align: center;
}

.app-icon {
  width: 76px;
  height: 76px;
  background: linear-gradient(135deg, #1e3a8a 0%, #3b82f6 50%, #60a5fa 100%);
  border-radius: 20px;
  margin: 0 auto 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 12px 30px var(--accent-glow);
  font-size: 2.2rem;
  color: white;
  font-weight: 700;
}

h1 {
  font-size: 2.3rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 0.5rem;
}

.subtitle {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.disclaimer-badge {
  display: inline-block;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--card-border);
  border-radius: 9999px;
  padding: 0.4rem 1.1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  max-width: 90%;
}

.section {
  margin-top: 3rem;
}

.section-title {
  font-size: 1.35rem;
  font-weight: 600;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  letter-spacing: -0.01em;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1rem;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.card:hover {
  border-color: var(--card-hover-border);
}

.faq-item {
  cursor: pointer;
}

.faq-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  font-size: 1.05rem;
}

.faq-icon {
  font-size: 1.2rem;
  transition: transform 0.2s ease;
  color: var(--text-muted);
}

.faq-content {
  margin-top: 0.75rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  display: none;
  border-top: 1px solid var(--card-border);
  padding-top: 0.75rem;
  line-height: 1.65;
}

.faq-item.open .faq-content {
  display: block;
}

.faq-item.open .faq-icon {
  transform: rotate(45deg);
}

pre {
  background: var(--code-bg);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 0.9rem;
  overflow-x: auto;
  font-size: 0.9rem;
  color: #93c5fd;
  margin: 0.75rem 0;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

.button-group {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  background: #2563eb;
  color: #fff;
  padding: 0.75rem 1.4rem;
  border-radius: 10px;
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: background 0.2s ease, transform 0.1s ease;
}

.btn:hover {
  background: #1d4ed8;
  transform: translateY(-1px);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--card-border);
  color: var(--text);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
}

/* App Store & TestFlight CTA */
.hero-actions { display: flex; justify-content: center; flex-wrap: wrap; gap: 0.85rem; margin-top: 1.5rem; }
.btn-appstore { background: linear-gradient(135deg, #2563eb 0%, #1d4ed8 100%); font-weight: 600; box-shadow: 0 6px 18px rgba(37, 99, 235, 0.4); transition: transform 0.15s ease, box-shadow 0.2s ease; }
.btn-appstore:hover { background: linear-gradient(135deg, #1d4ed8 0%, #1e40af 100%); transform: translateY(-2px); box-shadow: 0 10px 26px rgba(37, 99, 235, 0.55); }
.btn-tf { background: linear-gradient(135deg, #0284c7 0%, #0369a1 100%); font-weight: 600; box-shadow: 0 6px 18px rgba(2, 132, 199, 0.35); transition: transform 0.15s ease, box-shadow 0.2s ease; }
.btn-tf:hover { background: linear-gradient(135deg, #0369a1 0%, #075985 100%); transform: translateY(-2px); box-shadow: 0 10px 26px rgba(2, 132, 199, 0.5); }
.inline-link { color: #60a5fa; text-decoration: underline; text-underline-offset: 2px; }
.inline-link:hover { color: #93c5fd; }

footer {
  margin-top: 4rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  border-top: 1px solid var(--card-border);
  padding-top: 2rem;
}

footer a {
  color: var(--text-muted);
  text-decoration: underline;
  margin: 0 0.5rem;
}

footer a:hover {
  color: var(--text);
}

/* ===== App Showcase: horizontal snap strip ===== */
.showcase-header {
  margin-bottom: 1.25rem;
}

.showcase-header .section-title {
  margin-bottom: 0.35rem;
}

.showcase-subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.showcase-wrap {
  position: relative;
}

.showcase-track {
  display: flex;
  gap: 1rem;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior-x: contain;
  padding: 0.25rem 0.25rem 1rem;
  scrollbar-width: thin;
  scrollbar-color: rgba(255, 255, 255, 0.18) transparent;
}

.showcase-track::-webkit-scrollbar {
  height: 6px;
}

.showcase-track::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.18);
  border-radius: 9999px;
}

.shot-card {
  flex: 0 0 clamp(200px, 62vw, 236px);
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  text-align: left;
  font: inherit;
  color: inherit;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 0.6rem 0.6rem 0.9rem;
  cursor: zoom-in;
  transition: border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}

.shot-card:hover,
.shot-card:focus-visible {
  border-color: rgba(59, 130, 246, 0.55);
  transform: translateY(-4px);
  box-shadow: 0 14px 32px var(--accent-glow);
  outline: none;
}

.shot-card img {
  display: block;
  width: 100%;
  aspect-ratio: 1284 / 2778;
  object-fit: cover;
  border-radius: 10px;
  border: 1px solid var(--card-border);
  background: #000;
}

.shot-title {
  display: block;
  margin-top: 0.75rem;
  font-weight: 600;
  font-size: 0.98rem;
  letter-spacing: -0.01em;
}

.shot-desc {
  display: block;
  margin-top: 0.3rem;
  color: var(--text-muted);
  font-size: 0.85rem;
  line-height: 1.5;
}

.showcase-arrow {
  display: none;
  position: absolute;
  top: 40%;
  transform: translateY(-50%);
  z-index: 2;
  width: 42px;
  height: 42px;
  border-radius: 9999px;
  border: 1px solid var(--card-border);
  background: rgba(9, 10, 15, 0.78);
  color: var(--text);
  font-size: 1.25rem;
  line-height: 1;
  cursor: pointer;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transition: border-color 0.2s ease, background 0.2s ease, opacity 0.2s ease;
}

.showcase-arrow:hover {
  border-color: var(--accent);
  background: rgba(37, 99, 235, 0.35);
}

.showcase-arrow:disabled {
  opacity: 0.3;
  cursor: default;
}

.showcase-arrow.prev {
  left: -21px;
}

.showcase-arrow.next {
  right: -21px;
}

/* Arrows only on pointer-precise desktops; touch devices swipe natively */
@media (hover: hover) and (pointer: fine) and (min-width: 768px) {
  .showcase-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
  }
}

/* ===== Lightbox modal ===== */
.lightbox {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: none;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 0.9rem;
  padding: 1.5rem;
  background: rgba(3, 4, 8, 0.88);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  cursor: zoom-out;
}

.lightbox.open {
  display: flex;
  animation: lightbox-in 0.2s ease;
}

.lightbox img {
  max-width: min(92vw, 520px);
  max-height: calc(100vh - 7rem);
  width: auto;
  height: auto;
  border-radius: var(--radius);
  border: 1px solid var(--card-hover-border);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.6);
  cursor: default;
}

.lightbox-caption {
  color: var(--text);
  font-weight: 600;
  font-size: 0.98rem;
  text-align: center;
  cursor: default;
}

.lightbox-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  width: 40px;
  height: 40px;
  border-radius: 9999px;
  border: 1px solid var(--card-border);
  background: rgba(255, 255, 255, 0.08);
  color: var(--text);
  font-size: 1.4rem;
  line-height: 1;
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease;
}

.lightbox-close:hover {
  background: rgba(37, 99, 235, 0.35);
  border-color: var(--accent);
}

body.lightbox-lock {
  overflow: hidden;
}

@keyframes lightbox-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

@media (prefers-reduced-motion: reduce) {
  .showcase-track { scroll-behavior: auto; }
  .shot-card, .lightbox.open { transition: none; animation: none; }
  .shot-card:hover, .shot-card:focus-visible { transform: none; }
}