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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #1d1d1f;
  background: #fff;
  line-height: 1.6;
}

/* NAV */
nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,0.85);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid #e5e5e5;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 32px; height: 52px;
}
.nav-brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: inherit; }
.nav-brand img { width: 28px; height: 28px; border-radius: 7px; }
.nav-brand span { font-weight: 600; font-size: 17px; }
.nav-links { display: flex; align-items: center; gap: 24px; }
.nav-links a { text-decoration: none; color: #555; font-size: 15px; }
.nav-links a:hover { color: #000; }
.lang-btn {
  background: none; border: 1px solid #ccc; border-radius: 20px;
  padding: 4px 14px; font-size: 13px; cursor: pointer; color: #555;
}
.lang-btn:hover { border-color: #888; color: #000; }

/* HERO */
.hero {
  text-align: center;
  padding: 100px 24px 80px;
  background: linear-gradient(160deg, #f5fff7 0%, #fff 60%);
}
.hero .app-icon {
  width: 100px; height: 100px; border-radius: 22px;
  box-shadow: 0 8px 30px rgba(0,0,0,0.12);
  margin-bottom: 28px;
}
.hero h1 { font-size: 48px; font-weight: 700; letter-spacing: -0.5px; }
.hero .tagline { font-size: 20px; color: #555; margin: 16px auto 40px; max-width: 560px; }
.btn-appstore {
  display: inline-block;
  background: #000; color: #fff;
  padding: 14px 32px; border-radius: 30px;
  text-decoration: none; font-size: 17px; font-weight: 500;
  transition: background .2s;
}
.btn-appstore:hover { background: #333; }

/* FEATURES */
.features {
  max-width: 960px; margin: 0 auto;
  padding: 80px 24px;
  display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 40px;
}
.feature { text-align: center; }
.feature .icon { font-size: 40px; margin-bottom: 16px; }
.feature h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.feature p { font-size: 15px; color: #555; }

/* SCREENSHOTS */
.screenshots {
  padding: 64px 0 56px;
  overflow: hidden;
}
.screenshots-label {
  text-align: center;
  font-size: 13px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: #aaa;
  margin-bottom: 32px;
}
.screenshots-track {
  display: flex;
  gap: 24px;
  padding: 0 40px 20px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  justify-content: center;
}
.screenshots-track::-webkit-scrollbar { height: 4px; }
.screenshots-track::-webkit-scrollbar-thumb { background: #ddd; border-radius: 2px; }

/* iPhone frame */
.phone-frame {
  flex: 0 0 auto;
  scroll-snap-align: start;
  width: 230px;
  border-radius: 36px;
  background: #111;
  padding: 10px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.18);
  position: relative;
}
.phone-frame::before {
  content: '';
  display: block;
  width: 60px; height: 12px;
  background: #111;
  border-radius: 0 0 10px 10px;
  position: absolute;
  top: 10px; left: 50%; transform: translateX(-50%);
  z-index: 2;
}
.phone-frame img {
  width: 100%;
  aspect-ratio: 9 / 19.5;
  border-radius: 28px;
  object-fit: cover;
  display: block;
  background: #f0f0f0;
}
.screen-placeholder {
  display: none;
  width: 100%;
  aspect-ratio: 9 / 19.5;
  border-radius: 28px;
  background: linear-gradient(160deg, #e8f5ec 0%, #c8ecd3 100%);
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 8px;
  color: #5cb878;
}
.screen-placeholder span {
  font-size: 28px;
  font-weight: 700;
  opacity: 0.35;
}

/* SECTION DIVIDER */
.divider { border: none; border-top: 1px solid #eee; margin: 0 24px; }

/* CONTENT PAGE */
.page-header {
  background: linear-gradient(160deg, #f5fff7 0%, #fff 60%);
  padding: 72px 24px 48px; text-align: center;
}
.page-header h1 { font-size: 36px; font-weight: 700; }
.page-header p { color: #555; margin-top: 12px; }

.content {
  max-width: 760px; margin: 0 auto; padding: 56px 24px 80px;
}
.content h2 { font-size: 22px; font-weight: 600; margin: 40px 0 12px; }
.content h2:first-child { margin-top: 0; }
.content p { color: #333; margin-bottom: 14px; }
.content ul { padding-left: 20px; color: #333; margin-bottom: 14px; }
.content ul li { margin-bottom: 6px; }
.content a { color: #1a7a3f; }

/* FOOTER */
footer {
  text-align: center; padding: 40px 24px;
  font-size: 13px; color: #999;
  border-top: 1px solid #eee;
}
footer a { color: #999; text-decoration: none; margin: 0 10px; }
footer a:hover { color: #555; }

/* LANG TOGGLE */
[data-lang] { display: none; }
.zh [data-lang="zh"] { display: block; }
.zh [data-lang="zh"].inline { display: inline; }
.en [data-lang="en"] { display: block; }
.en [data-lang="en"].inline { display: inline; }