/* ── Reset & Variables ── */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}

:root {
  --c-primary: #3B82F6;
  --c-primary-dark: #2563EB;
  --c-primary-light: #60A5FA;
  --c-bg: #ffffff;
  --c-bg2: #f8fafc;
  --c-bg3: #f1f5f9;
  --c-text: #1e293b;
  --c-text2: #475569;
  --c-text3: #94a3b8;
  --c-border: #e2e8f0;
  --c-card: #ffffff;
  --c-hero-from: #eff6ff;
  --c-hero-to: #ffffff;
  --shadow-sm: 0 1px 3px rgba(0,0,0,.06);
  --shadow-md: 0 4px 16px rgba(0,0,0,.08);
  --shadow-lg: 0 8px 32px rgba(0,0,0,.1);
  --radius: 12px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --c-bg: #0f172a;
    --c-bg2: #1e293b;
    --c-bg3: #334155;
    --c-text: #f1f5f9;
    --c-text2: #cbd5e1;
    --c-text3: #64748b;
    --c-border: #334155;
    --c-card: #1e293b;
    --c-hero-from: #0f172a;
    --c-hero-to: #1e293b;
    --shadow-sm: 0 1px 3px rgba(0,0,0,.3);
    --shadow-md: 0 4px 16px rgba(0,0,0,.4);
    --shadow-lg: 0 8px 32px rgba(0,0,0,.5);
  }
}

html { scroll-behavior: smooth }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
  color: var(--c-text);
  background: var(--c-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--c-primary); text-decoration: none }

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

/* ── Nav ── */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--c-border);
  transition: box-shadow .3s;
}

@media (prefers-color-scheme: dark) {
  .nav { background: rgba(15,23,42,.85) }
}

.nav.scrolled { box-shadow: var(--shadow-sm) }

.nav-inner {
  max-width: 1080px; margin: 0 auto; padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between; height: 56px;
}

.nav-logo {
  font-size: 18px; font-weight: 700; color: var(--c-text);
  display: flex; align-items: center; gap: 8px;
}
.nav-logo svg { width: 28px; height: 28px }

.nav-links { display: flex; gap: 24px; align-items: center }
.nav-links a { font-size: 14px; color: var(--c-text2); transition: color .2s }
.nav-links a:hover { color: var(--c-primary) }

.nav-links .btn-sm {
  padding: 5px 14px; font-size: 13px; font-weight: 500;
  border-radius: 6px; color: #fff; box-shadow: none;
}
.nav-links .btn-sm:hover { color: #fff }

.nav-btn {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: 14px; font-weight: 500; color: var(--c-primary); transition: color .2s;
  border: none; cursor: pointer; background: none; padding: 0;
}
.nav-btn:hover { color: var(--c-primary-dark) }

/* Language Switcher */
.lang-switcher {
  position: relative;
}
.lang-btn {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 6px 10px; border-radius: 6px; font-size: 13px;
  background: transparent; color: var(--c-text2); border: 1px solid var(--c-border);
  cursor: pointer; transition: all .2s;
}
.lang-btn:hover { border-color: var(--c-primary); color: var(--c-primary) }
.lang-btn svg { width: 16px; height: 16px }

.lang-dropdown {
  display: none; position: absolute; top: 100%; right: 0; margin-top: 6px;
  background: var(--c-card); border: 1px solid var(--c-border);
  border-radius: 8px; box-shadow: var(--shadow-md);
  min-width: 120px; padding: 4px; z-index: 200;
}
.lang-dropdown.open { display: block }
.lang-dropdown button {
  display: block; width: 100%; text-align: left;
  padding: 8px 12px; border: none; background: none;
  font-size: 13px; color: var(--c-text); cursor: pointer;
  border-radius: 6px; transition: background .15s;
}
.lang-dropdown button:hover { background: var(--c-bg2) }
.lang-dropdown button.active { color: var(--c-primary); font-weight: 600 }

/* ── Hero ── */
.hero {
  padding: 140px 0 80px;
  background: linear-gradient(180deg, var(--c-hero-from) 0%, var(--c-hero-to) 100%);
  position: relative; overflow: hidden; text-align: center;
}

.hero::before {
  content: ''; position: absolute; inset: 0;
  background:
    radial-gradient(circle at 20% 50%, rgba(59,130,246,.06) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(59,130,246,.04) 0%, transparent 50%);
}

.hero-content { position: relative; z-index: 1 }

.hero-badge {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 6px 14px; border-radius: 999px; font-size: 13px; font-weight: 500;
  background: rgba(59,130,246,.08); color: var(--c-primary); margin-bottom: 24px;
  border: 1px solid rgba(59,130,246,.15);
}

.hero h1 {
  font-size: clamp(36px, 6vw, 56px); font-weight: 800;
  letter-spacing: -.02em; line-height: 1.15; margin-bottom: 8px;
}
.hero h1 span {
  background: linear-gradient(135deg, var(--c-primary), #8B5CF6);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-sub {
  font-size: clamp(16px, 2.5vw, 20px); color: var(--c-text2);
  margin-bottom: 12px; font-weight: 500;
}

.hero-desc {
  font-size: 15px; color: var(--c-text3);
  max-width: 520px; margin: 0 auto 36px; line-height: 1.7;
}

.hero-actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap }

.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 28px; border-radius: 10px; font-size: 15px; font-weight: 600;
  transition: all .2s; border: none; cursor: pointer;
}

.btn-primary {
  background: var(--c-primary); color: #fff;
  box-shadow: 0 4px 14px rgba(59,130,246,.3);
}
.btn-primary:hover {
  background: var(--c-primary-dark); transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(59,130,246,.35); color: #fff;
}

.btn-secondary {
  background: var(--c-bg); color: var(--c-text);
  border: 1px solid var(--c-border); box-shadow: var(--shadow-sm);
}
.btn-secondary:hover {
  border-color: var(--c-primary); color: var(--c-primary);
  transform: translateY(-1px);
}

/* ── Features ── */
.features { padding: 80px 0 }

.section-label {
  text-align: center; font-size: 13px; font-weight: 600;
  text-transform: uppercase; letter-spacing: .08em;
  color: var(--c-primary); margin-bottom: 12px;
}

.section-title {
  text-align: center; font-size: clamp(24px, 4vw, 32px);
  font-weight: 700; margin-bottom: 12px;
}

.section-desc {
  text-align: center; font-size: 15px; color: var(--c-text2);
  max-width: 500px; margin: 0 auto 48px;
}

.features-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 20px;
}

.feature-card {
  background: var(--c-card); border: 1px solid var(--c-border);
  border-radius: var(--radius); padding: 28px; transition: all .3s;
}
.feature-card:hover {
  transform: translateY(-3px); box-shadow: var(--shadow-md);
  border-color: var(--c-primary-light);
}

.feature-icon {
  width: 44px; height: 44px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 16px; font-size: 22px;
}

.feature-card h3 { font-size: 16px; font-weight: 600; margin-bottom: 8px }
.feature-card p { font-size: 14px; color: var(--c-text2); line-height: 1.6 }

.fi-classify { background: rgba(59,130,246,.1); color: #3B82F6 }
.fi-format   { background: rgba(16,185,129,.1); color: #10B981 }
.fi-privacy  { background: rgba(245,158,11,.1); color: #F59E0B }
.fi-hotkey   { background: rgba(139,92,246,.1); color: #8B5CF6 }
.fi-local    { background: rgba(239,68,68,.1);  color: #EF4444 }
.fi-lang     { background: rgba(6,182,212,.1);  color: #06B6D4 }

/* ── Screenshot ── */
.screenshot { padding: 80px 0; background: var(--c-bg) }

.carousel-wrapper {
  position: relative;
  max-width: 1000px;
  margin: 0 auto;
  padding: 20px 0 20px;
  user-select: none;
}

.carousel-viewport {
  overflow: hidden;
  padding: 20px 0 30px;
  cursor: grab;
}
.carousel-viewport.dragging { cursor: grabbing }

.carousel-track {
  display: flex;
  gap: 20px;
  transition: transform .45s cubic-bezier(.4,0,.2,1);
  will-change: transform;
}
.carousel-track.no-transition { transition: none }
.carousel-track.no-transition img { transition: none }

.carousel-track img {
  flex: 0 0 55%;
  max-width: 55%;
  border-radius: 0;
  box-shadow: none;
  transition: transform .45s cubic-bezier(.4,0,.2,1), opacity .45s ease;
  opacity: 0.35;
  transform: scale(0.82);
  pointer-events: none;
  object-fit: contain;
  image-rendering: -webkit-optimize-contrast;
}

.carousel-track img.active {
  opacity: 1;
  transform: scale(1);
  box-shadow: none;
  pointer-events: auto;
}

.carousel-arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-60%);
  z-index: 5;
  width: 40px; height: 40px;
  border-radius: 50%;
  border: 1px solid var(--c-border);
  background: var(--c-card);
  color: var(--c-text2);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: all .2s;
  opacity: 0;
}
.carousel-wrapper:hover .carousel-arrow { opacity: 1 }
.carousel-arrow:hover {
  background: var(--c-primary); color: #fff; border-color: var(--c-primary);
  box-shadow: var(--shadow-md);
}
.carousel-arrow.prev { left: 8px }
.carousel-arrow.next { right: 8px }

.carousel-dots {
  display: flex; gap: 8px; justify-content: center;
  margin-top: 0; position: relative; z-index: 2;
}
.carousel-dots button {
  width: 8px; height: 8px; border-radius: 50%; border: none; padding: 0;
  background: var(--c-border); cursor: pointer; transition: all .3s;
}
.carousel-dots button.active {
  background: var(--c-primary); width: 24px; border-radius: 4px;
}

.carousel-empty {
  text-align: center; color: var(--c-text3); font-size: 14px; padding: 60px 0;
}
.carousel-track:not(:empty) ~ .carousel-dots ~ .carousel-empty { display: none }

/* ── Privacy Notice ── */
.privacy-notice { padding: 80px 0; background: var(--c-bg2) }

.privacy-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 20px;
}

.privacy-card {
  background: var(--c-card); border: 1px solid var(--c-border);
  border-radius: var(--radius); padding: 28px; transition: all .3s;
}
.privacy-card:hover {
  transform: translateY(-3px); box-shadow: var(--shadow-md);
}

.privacy-icon {
  width: 44px; height: 44px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 16px;
}

.privacy-card h3 { font-size: 16px; font-weight: 600; margin-bottom: 8px }
.privacy-card p { font-size: 14px; color: var(--c-text2); line-height: 1.6 }

.pi-detect  { background: rgba(59,130,246,.1); color: #3B82F6 }
.pi-warn    { background: rgba(245,158,11,.1); color: #F59E0B }
.pi-info    { background: rgba(139,92,246,.1); color: #8B5CF6 }
.pi-offline { background: rgba(16,185,129,.1); color: #10B981 }
.pi-db      { background: rgba(239,68,68,.1);  color: #EF4444 }

/* ── Download ── */
.download { padding: 80px 0 }

.download-box {
  max-width: 560px; margin: 0 auto; background: var(--c-card);
  border: 1px solid var(--c-border); border-radius: 16px;
  padding: 40px; text-align: center; box-shadow: var(--shadow-md);
}

.download-box h3 { font-size: 22px; font-weight: 700; margin-bottom: 8px }
.download-box .download-sub { font-size: 14px; color: var(--c-text2); margin-bottom: 28px }

.download-btns {
  display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-bottom: 20px;
}

.download-btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 28px; border-radius: 10px; font-size: 15px; font-weight: 600;
  transition: all .2s; border: none; cursor: pointer; text-decoration: none;
}

.download-btn-main {
  background: var(--c-primary); color: #fff;
  box-shadow: 0 4px 14px rgba(59,130,246,.25);
}
.download-btn-main:hover { background: var(--c-primary-dark); transform: translateY(-1px); color: #fff }

.download-btn-alt {
  background: var(--c-bg2); color: var(--c-text); border: 1px solid var(--c-border);
}
.download-btn-alt:hover {
  border-color: var(--c-primary); color: var(--c-primary); transform: translateY(-1px);
}

.download-meta {
  font-size: 12px; color: var(--c-text3);
  display: flex; gap: 16px; justify-content: center; flex-wrap: wrap;
}
.download-meta span { display: inline-flex; align-items: center; gap: 4px }

/* ── Footer ── */
.footer {
  padding: 32px 0; border-top: 1px solid var(--c-border);
  text-align: center; font-size: 13px; color: var(--c-text3);
}

/* ── Animations ── */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .6s ease, transform .6s ease }
.reveal.visible { opacity: 1; transform: none }

/* ── Responsive ── */
@media (max-width: 640px) {
  .hero { padding: 120px 0 60px }
  .features-grid { grid-template-columns: 1fr }
  .nav-links a:not(.nav-btn):not(.lang-switcher) { display: none }
  .download-box { padding: 28px 20px }
  .carousel-track img { flex: 0 0 75%; max-width: 75% }
  .carousel-arrow { width: 32px; height: 32px; opacity: 1 }
}