/* ==================== RESET & BASE ==================== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  color: rgba(0,0,0,.85);
  background: #fff;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; }
button { border: none; background: none; cursor: pointer; font: inherit; }

/* ==================== VARIABLES ==================== */
:root {
  --primary: #3c80ff;
  --primary-dark: #1a69ff;
  --primary-gradient: linear-gradient(96deg, #1a69ff, #3c80ff);
  --accent: #f64e60;
  --dark: #1b1f35;
  --text: rgba(0,0,0,.85);
  --text-secondary: #5e6278;
  --text-muted: #878999;
  --text-light: #bbbdc9;
  --bg-light: #f7f9fe;
  --bg-gray: #fafafa;
  --bg-card: rgba(182,186,195,.1);
  --border: rgba(182,186,195,.15);
  --shadow-sm: 0 2px 12px rgba(0,0,0,.06);
  --shadow-md: 0 8px 30px rgba(0,0,0,.08);
  --shadow-lg: 0 20px 60px rgba(0,0,0,.12);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 20px;
  --nav-h: 64px;
  --max-w: 1200px;
}

/* ==================== UTILITY ==================== */
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 24px; }

/* ==================== BUTTONS ==================== */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 24px; border-radius: var(--radius-sm);
  font-weight: 600; font-size: .9rem; transition: all .25s;
  white-space: nowrap;
}
.btn-primary {
  background: var(--primary-gradient); color: #fff;
  box-shadow: 0 4px 16px rgba(28,105,255,.3);
}
.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 6px 24px rgba(28,105,255,.4); }
.btn-primary-sm {
  background: var(--primary-gradient); color: #fff;
  padding: 8px 20px; border-radius: var(--radius-sm); font-size: .85rem;
  box-shadow: 0 2px 10px rgba(28,105,255,.25);
}
.btn-primary-sm:hover { box-shadow: 0 4px 16px rgba(28,105,255,.35); }
.btn-outline {
  border: 2px solid var(--primary); color: var(--primary); background: transparent;
}
.btn-outline:hover { background: var(--primary); color: #fff; }
.btn-ghost {
  color: var(--text-secondary); padding: 8px 16px; font-weight: 500;
}
.btn-ghost:hover { color: var(--primary); }
.btn-lg { padding: 14px 36px; font-size: 1rem; border-radius: var(--radius); }

/* ==================== NAVBAR ==================== */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  height: var(--nav-h);
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow .3s;
}
.navbar.scrolled { box-shadow: var(--shadow-sm); }
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 100%;
}
.logo {
  display: flex; align-items: center; gap: 8px; font-size: 1.3rem; font-weight: 800;
}
.logo-icon {
  width: 36px; height: 36px; border-radius: 10px;
  background: var(--primary-gradient); color: #fff;
  display: flex; align-items: center; justify-content: center; font-size: 1.1rem;
}
.logo-text { color: var(--dark); }
.logo-highlight { color: var(--primary); }
.nav-links { display: flex; gap: 32px; }
.nav-links a {
  color: var(--text-secondary); font-size: .9rem; font-weight: 500;
  transition: color .2s; position: relative;
}
.nav-links a::after {
  content: ''; position: absolute; bottom: -4px; left: 0; right: 0;
  height: 2px; background: var(--primary); transform: scaleX(0); transition: transform .25s;
}
.nav-links a:hover { color: var(--primary); }
.nav-links a:hover::after { transform: scaleX(1); }
.nav-actions { display: flex; align-items: center; gap: 12px; }
.mobile-menu { display: none; font-size: 1.4rem; color: var(--dark); padding: 8px; }

/* ==================== HERO ==================== */
.hero {
  position: relative; min-height: 580px;
  display: flex; align-items: center;
  padding-top: var(--nav-h); overflow: hidden;
}
.hero-bg {
  position: absolute; inset: 0; z-index: -1;
  background: linear-gradient(160deg, #f0f4ff 0%, #e8f0ff 30%, #f7f9fe 60%, #fff 100%);
}
.hero-bg::before {
  content: ''; position: absolute; top: -120px; right: -100px;
  width: 600px; height: 600px; border-radius: 50%;
  background: radial-gradient(circle, rgba(60,128,255,.08) 0%, transparent 70%);
}
.hero-bg::after {
  content: ''; position: absolute; bottom: -80px; left: -60px;
  width: 400px; height: 400px; border-radius: 50%;
  background: radial-gradient(circle, rgba(246,78,96,.05) 0%, transparent 70%);
}
.hero-content {
  text-align: center; padding: 80px 0 60px;
}
.hero-title {
  font-size: 3.5rem; font-weight: 900; line-height: 1.2;
  color: var(--dark); margin-bottom: 20px;
  background: linear-gradient(135deg, #1b1f35 0%, #3c80ff 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-sub {
  font-size: 1.2rem; color: var(--text-secondary); margin-bottom: 40px;
}
.hero-cta { display: flex; gap: 16px; justify-content: center; margin-bottom: 60px; }
.hero-stats {
  display: flex; gap: 60px; justify-content: center;
}
.stat { display: flex; flex-direction: column; align-items: center; }
.stat-num {
  font-size: 2rem; font-weight: 800;
  background: var(--primary-gradient); -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.stat-label { font-size: .85rem; color: var(--text-muted); margin-top: 4px; }

/* ==================== FEATURES TAB NAV ==================== */
.features-nav {
  position: sticky; top: var(--nav-h); z-index: 100;
  background: rgba(255,255,255,.95); backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border); padding: 12px 0;
}
.features-tabs {
  display: flex; gap: 8px; overflow-x: auto; scrollbar-width: none;
  -ms-overflow-style: none; padding: 4px 0;
}
.features-tabs::-webkit-scrollbar { display: none; }
.tab {
  display: flex; align-items: center; gap: 6px;
  padding: 10px 20px; border-radius: 50px;
  font-size: .85rem; font-weight: 500; color: var(--text-secondary);
  white-space: nowrap; transition: all .25s;
  border: 1px solid transparent;
}
.tab:hover { color: var(--primary); background: rgba(60,128,255,.06); }
.tab.active {
  color: var(--primary); background: rgba(60,128,255,.1);
  border-color: rgba(60,128,255,.2);
}

/* ==================== FEATURE SECTIONS ==================== */
.feature-section {
  padding: 100px 0;
}
.feature-section.alt-bg { background: var(--bg-light); }
.section-title {
  font-size: 2rem; font-weight: 800; text-align: center;
  color: var(--dark); margin-bottom: 16px;
}
.section-sub {
  text-align: center; color: var(--text-muted); font-size: 1rem; margin-bottom: 48px;
}

/* Feature Grid */
.feature-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 60px;
  align-items: center;
}
.feature-grid.reverse .feature-visual { order: 2; }
.feature-grid.reverse .feature-text { order: 1; }
.feature-text h2 {
  font-size: 2rem; font-weight: 800; color: var(--dark); margin-bottom: 16px;
}
.feature-text p {
  color: var(--text-secondary); font-size: 1rem; line-height: 1.8; margin-bottom: 24px;
}
.feature-list { margin-top: 16px; }
.feature-list li {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 0; color: var(--text-secondary); font-size: .95rem;
}
.feature-list li i { color: var(--primary); font-size: .85rem; }

/* ==================== URL DEMO ==================== */
.url-demo {
  background: var(--dark); border-radius: var(--radius-lg); overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.url-bar {
  display: flex; align-items: center; gap: 8px;
  padding: 14px 18px; background: #2a2e45;
}
.url-dot { width: 10px; height: 10px; border-radius: 50%; }
.url-dot.red { background: #ff5f57; }
.url-dot.yellow { background: #febc2e; }
.url-dot.green { background: #28c840; }
.url-address {
  margin-left: 12px; color: #8f95b0; font-size: .8rem;
  font-family: "SF Mono", "Fira Code", monospace;
}
.url-content { padding: 20px; }
.url-row {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 16px; border-radius: var(--radius-sm);
  color: #c5c9d8; font-size: .9rem;
  background: rgba(255,255,255,.05); margin-bottom: 8px;
}
.url-row i { color: var(--primary); width: 20px; text-align: center; }
.tag {
  margin-left: auto; padding: 2px 10px; border-radius: 50px;
  background: rgba(60,128,255,.15); color: var(--primary); font-size: .75rem;
}
.url-status {
  padding: 14px 20px; color: #28c840; font-size: .85rem;
  border-top: 1px solid rgba(255,255,255,.08);
}
.url-status i { margin-right: 6px; }

/* ==================== SPEED CARDS ==================== */
.speed-cards {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px;
  margin-bottom: 40px;
}
.speed-card {
  padding: 24px; border-radius: var(--radius);
  background: #fff; border: 1px solid var(--border);
  cursor: pointer; transition: all .3s;
}
.speed-card:hover, .speed-card.active {
  border-color: var(--primary); box-shadow: 0 4px 20px rgba(60,128,255,.12);
}
.speed-card.active { background: rgba(60,128,255,.04); }
.speed-icon {
  width: 48px; height: 48px; border-radius: 12px;
  background: rgba(60,128,255,.1); color: var(--primary);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.2rem; margin-bottom: 16px;
}
.speed-card h3 { font-size: 1rem; font-weight: 700; margin-bottom: 8px; color: var(--dark); }
.speed-card p { font-size: .85rem; color: var(--text-muted); line-height: 1.5; }

.speed-detail {
  background: #fff; border-radius: var(--radius-lg);
  padding: 40px; border: 1px solid var(--border);
}
.speed-detail-item { display: none; }
.speed-detail-item.active { display: block; }

/* Speed Meter */
.speed-meter { margin-bottom: 20px; }
.meter-bar {
  height: 40px; background: #e8ecf4; border-radius: 20px; overflow: hidden;
  position: relative;
}
.meter-bar::after {
  content: ''; position: absolute; top: 0; left: 0; bottom: 0;
  width: var(--target); background: var(--primary-gradient); border-radius: 20px;
  animation: meterFill 1.5s ease-out;
}
.meter-bar span {
  position: relative; z-index: 1; line-height: 40px;
  padding: 0 20px; color: #fff; font-weight: 700; font-size: .9rem;
}
@keyframes meterFill { from { width: 0; } }

/* Capacity Bars */
.capacity-bars { display: flex; flex-direction: column; gap: 16px; }
.cap-row { display: flex; align-items: center; gap: 16px; }
.cap-row > span { width: 80px; font-size: .85rem; color: var(--text-secondary); text-align: right; }
.cap-bar {
  flex: 1; max-width: var(--w); height: 36px; border-radius: 18px;
  background: var(--primary-gradient); color: #fff; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  font-size: .85rem; animation: capGrow 1s ease-out;
}
@keyframes capGrow { from { max-width: 0; } }

/* File Ring */
.file-size-demo { display: flex; justify-content: center; }
.file-ring { position: relative; width: 160px; height: 160px; }
.file-ring svg { width: 100%; height: 100%; transform: rotate(-90deg); }
.file-ring circle:last-of-type { animation: ringDraw 1.5s ease-out; }
@keyframes ringDraw { from { stroke-dashoffset: 314; } }
.ring-text {
  position: absolute; top: 50%; left: 50%; transform: translate(-50%, -60%);
  font-size: 1.6rem; font-weight: 800; color: var(--dark);
}
.ring-sub {
  position: absolute; top: 50%; left: 50%; transform: translate(-50%, 40%);
  font-size: .8rem; color: var(--text-muted);
}

/* Dedup Demo */
.dedup-demo { display: flex; flex-direction: column; align-items: center; gap: 20px; }
.dedup-file {
  display: flex; align-items: center; gap: 10px;
  padding: 16px 24px; background: #fff; border-radius: var(--radius);
  border: 1px solid var(--border); font-size: .95rem;
}
.dedup-file i { color: var(--primary); }
.dedup-arrow { color: var(--text-muted); font-size: .9rem; }
.dedup-saved {
  display: flex; align-items: center; gap: 8px;
  padding: 12px 24px; border-radius: 50px;
  background: rgba(40,200,64,.1); color: #28c840; font-weight: 600;
}

/* ==================== SHARE DEMO ==================== */
.share-demo { display: flex; justify-content: center; }
.share-phone {
  width: 300px; background: #fff; border-radius: 32px;
  border: 3px solid var(--dark); overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.phone-notch {
  width: 100px; height: 24px; margin: 0 auto;
  background: var(--dark); border-radius: 0 0 16px 16px;
}
.phone-screen { padding: 20px; }
.share-header {
  display: flex; align-items: center; gap: 8px;
  font-weight: 700; color: var(--primary); margin-bottom: 20px;
  font-size: 1rem;
}
.share-file-list { margin-bottom: 20px; }
.share-file {
  display: flex; align-items: center; gap: 10px;
  padding: 12px; border-radius: var(--radius-sm);
  background: var(--bg-light); margin-bottom: 8px; font-size: .85rem;
}
.share-file i { color: var(--primary); }
.share-file span { margin-left: auto; color: var(--text-muted); font-size: .8rem; }
.share-download-btn {
  width: 100%; padding: 14px; border-radius: var(--radius-sm);
  background: var(--primary-gradient); color: #fff; font-weight: 700;
  font-size: .95rem; display: flex; align-items: center; justify-content: center; gap: 8px;
  box-shadow: 0 4px 16px rgba(28,105,255,.3);
}
.share-hint {
  text-align: center; color: var(--text-muted); font-size: .8rem; margin-top: 12px;
}

/* ==================== MIGRATE DEMO ==================== */
.migrate-demo { padding: 30px; }
.migrate-from {
  display: flex; align-items: center; justify-content: center; gap: 24px;
  margin-bottom: 30px;
}
.migrate-disk {
  display: flex; flex-direction: column; align-items: center; gap: 8px;
  padding: 24px; border-radius: var(--radius);
  font-size: .9rem; font-weight: 600;
}
.migrate-disk.other { background: rgba(135,137,153,.1); color: var(--text-secondary); }
.migrate-disk.ours { background: rgba(60,128,255,.1); color: var(--primary); }
.migrate-disk i { font-size: 2rem; }
.migrate-arrow { color: var(--primary); font-size: 1.2rem; animation: arrowPulse 1.5s infinite; }
@keyframes arrowPulse { 0%,100% { opacity: 1; } 50% { opacity: .4; } }
.migrate-progress { margin-bottom: 16px; }
.progress-bar {
  height: 8px; background: #e8ecf4; border-radius: 4px; overflow: hidden; margin-bottom: 8px;
}
.progress-fill {
  height: 100%; background: var(--primary-gradient); border-radius: 4px;
  animation: progressGrow 2s ease-out;
}
@keyframes progressGrow { from { width: 0; } }
.migrate-progress span { font-size: .85rem; color: var(--text-muted); }
.migrate-tip {
  text-align: center; font-size: .85rem; color: var(--primary); font-weight: 600;
}

/* ==================== SYNC CARDS ==================== */
.sync-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.sync-card {
  padding: 36px 28px; border-radius: var(--radius-lg);
  background: #fff; border: 1px solid var(--border);
  transition: all .3s; text-align: center;
}
.sync-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.sync-icon {
  width: 64px; height: 64px; border-radius: 16px; margin: 0 auto 20px;
  background: rgba(60,128,255,.08); color: var(--primary);
  display: flex; align-items: center; justify-content: center; font-size: 1.5rem;
}
.sync-card h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 12px; color: var(--dark); }
.sync-card p { font-size: .9rem; color: var(--text-muted); line-height: 1.7; }

/* ==================== PAY DEMO ==================== */
.pay-demo { display: flex; justify-content: center; }
.pay-card {
  width: 320px; background: #fff; border-radius: var(--radius-lg);
  overflow: hidden; box-shadow: var(--shadow-lg);
}
.pay-header {
  padding: 20px 24px; background: var(--primary-gradient);
  color: #fff; font-weight: 700; font-size: 1rem;
}
.pay-header i { margin-right: 8px; }
.pay-item {
  display: flex; justify-content: space-between; align-items: center;
  padding: 16px 24px; border-bottom: 1px solid var(--border);
  font-size: .9rem;
}
.pay-price { color: var(--accent); font-weight: 700; font-size: 1.1rem; }
.pay-tip {
  padding: 16px 24px; text-align: center;
  color: var(--accent); font-size: .85rem;
}

/* ==================== TRANSFER DEMO ==================== */
.transfer-demo {
  display: flex; flex-direction: column; align-items: center;
  gap: 30px; padding: 30px;
}
.transfer-device {
  display: flex; flex-direction: column; align-items: center; gap: 8px;
  padding: 24px 32px; border-radius: var(--radius-lg);
  background: #fff; border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}
.transfer-device i { font-size: 2.5rem; color: var(--primary); }
.transfer-device span { font-size: .85rem; color: var(--text-muted); font-weight: 600; }
.transfer-wave { position: relative; height: 40px; width: 200px; }
.wave-line {
  position: absolute; top: 50%; left: 0; right: 0;
  height: 2px; background: var(--primary);
  animation: waveMove 1.5s infinite;
}
.wave-line.delay1 { animation-delay: .3s; opacity: .5; top: 30%; }
.wave-line.delay2 { animation-delay: .6s; opacity: .3; top: 70%; }
@keyframes waveMove {
  0% { transform: scaleX(0); opacity: 0; }
  50% { transform: scaleX(1); opacity: 1; }
  100% { transform: scaleX(0); opacity: 0; }
}
.transfer-info {
  display: flex; gap: 24px; font-size: .85rem; color: var(--text-muted);
}

/* ==================== OPEN DEMO ==================== */
.open-demo { display: flex; flex-direction: column; align-items: center; padding: 30px; }
.open-center {
  width: 80px; height: 80px; border-radius: 50%;
  background: var(--primary-gradient); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 2rem; box-shadow: 0 8px 30px rgba(60,128,255,.3);
  z-index: 2; position: relative;
}
.open-orbit { position: relative; width: 280px; height: 280px; margin-top: -160px; }
.orbit-item {
  position: absolute; width: 48px; height: 48px; border-radius: 12px;
  background: #fff; border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  color: var(--primary); font-size: 1.1rem;
  box-shadow: var(--shadow-sm);
  top: 50%; left: 50%;
  transform: translate(-50%, -50%) rotate(calc(var(--i) * 90deg)) translateY(-110px) rotate(calc(var(--i) * -90deg));
}
.open-label {
  margin-top: 16px; font-size: .85rem; color: var(--text-muted); font-weight: 600;
}

/* ==================== DOWNLOAD ==================== */
.download-section {
  padding: 100px 0; background: var(--bg-light);
}
.download-cards {
  display: flex; gap: 20px; justify-content: center; flex-wrap: wrap;
}
.dl-card {
  display: flex; flex-direction: column; align-items: center; gap: 12px;
  padding: 32px 28px; border-radius: var(--radius-lg);
  background: #fff; border: 1px solid var(--border);
  min-width: 140px; transition: all .3s;
}
.dl-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.dl-icon { font-size: 2.5rem; color: var(--primary); }
.dl-card span { font-weight: 600; font-size: .9rem; color: var(--dark); }

/* ==================== FOOTER ==================== */
.footer {
  background: var(--dark); color: rgba(255,255,255,.7); padding: 60px 0 30px;
}
.footer-inner { display: flex; flex-wrap: wrap; gap: 40px; }
.footer-brand { flex: 1; min-width: 200px; }
.footer-brand .logo { margin-bottom: 12px; }
.footer-brand .logo-text { color: #fff; }
.footer-brand p { font-size: .9rem; }
.footer-links {
  display: flex; gap: 60px; flex: 2; justify-content: center;
}
.footer-col h4 {
  color: #fff; font-size: .95rem; font-weight: 700; margin-bottom: 16px;
}
.footer-col a {
  display: block; font-size: .85rem; padding: 4px 0;
  transition: color .2s;
}
.footer-col a:hover { color: var(--primary); }
.footer-certs {
  width: 100%; display: flex; gap: 24px; flex-wrap: wrap;
  padding: 20px 0; border-top: 1px solid rgba(255,255,255,.1);
  margin-top: 20px;
}
.footer-certs span {
  font-size: .75rem; color: rgba(255,255,255,.4);
  padding: 4px 12px; border-radius: 4px;
  background: rgba(255,255,255,.05);
}
.footer-bottom {
  width: 100%; text-align: center; padding-top: 20px;
  border-top: 1px solid rgba(255,255,255,.08);
}
.footer-bottom p { font-size: .8rem; color: rgba(255,255,255,.35); margin-bottom: 4px; }

/* ==================== FLOATING ACTIONS ==================== */
.floating-actions {
  position: fixed; bottom: 30px; right: 30px;
  display: flex; flex-direction: column; gap: 12px; z-index: 999;
}
.fab {
  width: 48px; height: 48px; border-radius: 50%;
  display: flex !important; align-items: center; justify-content: center;
  color: #fff; font-size: 1.1rem; line-height: 1; overflow: hidden;
  box-shadow: 0 4px 16px rgba(0,0,0,.15);
  transition: all .3s; opacity: 0; transform: translateY(20px);
}
.fab.visible { opacity: 1; transform: translateY(0); }
.fab-top { background: var(--dark); }
.fab-top:hover { background: var(--primary); }
.fab-service { background: var(--primary-gradient); }
.fab-service:hover { transform: scale(1.1); }

/* ==================== RESPONSIVE ==================== */
@media (max-width: 1024px) {
  .feature-grid { grid-template-columns: 1fr; gap: 40px; }
  .feature-grid.reverse .feature-visual { order: 0; }
  .feature-grid.reverse .feature-text { order: 0; }
  .speed-cards { grid-template-columns: repeat(2, 1fr); }
  .sync-cards { grid-template-columns: 1fr; }
  .footer-links { gap: 30px; }
}
@media (max-width: 768px) {
  .nav-links { display: none; }
  .mobile-menu { display: block; }
  .hero-title { font-size: 2.2rem; }
  .hero-stats { gap: 30px; }
  .stat-num { font-size: 1.5rem; }
  .features-tabs { gap: 4px; }
  .tab { padding: 8px 14px; font-size: .8rem; }
  .speed-cards { grid-template-columns: 1fr; }
  .download-cards { gap: 12px; }
  .dl-card { min-width: 100px; padding: 20px 16px; }
  .footer-inner { flex-direction: column; }
  .footer-links { flex-direction: column; gap: 20px; }
  .hero-cta { flex-direction: column; align-items: center; }
}