:root {
  --red: #e62e4d;
  --red-hover: #cf2845;
  --red-soft: #fff5f7;
  --bg: #f5f6f8;
  --paper: #ffffff;
  --text: #22242e;
  --muted: #6b7280;
  --line: #e5e7eb;
  --line-dark: #d1d5db;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.06), 0 4px 16px rgba(16, 24, 40, 0.04);
}

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

body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-size: 15px;
}

a { color: var(--red); text-decoration: none; }
a:hover { color: var(--red-hover); }

.wrap { max-width: 1040px; margin: 0 auto; padding: 0 20px; }

/* header */
.site-header {
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 50;
}
.header-row {
  display: flex;
  align-items: center;
  gap: 24px;
  min-height: 60px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  flex-shrink: 0;
}
.brand:hover { color: var(--text); }
.brand img { border-radius: 6px; display: block; }
.brand-text { display: flex; flex-direction: column; line-height: 1.25; }
.brand-text strong { font-size: 16px; font-weight: 600; }
.brand-text small { font-size: 11px; color: var(--muted); font-weight: 400; }

.site-nav { flex: 1; }
.site-nav ul { display: flex; gap: 4px; list-style: none; }
.site-nav a {
  display: block;
  padding: 8px 14px;
  border-radius: 6px;
  color: #4b5563;
  font-size: 14px;
}
.site-nav a:hover { background: #f3f4f6; color: var(--text); text-decoration: none; }
.site-nav a.on { color: var(--red); background: var(--red-soft); font-weight: 600; }

.header-cta { margin-left: auto; }
.nav-toggle {
  display: none;
  width: 36px; height: 36px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
  cursor: pointer;
  margin-left: auto;
}
.nav-toggle span,
.nav-toggle::before,
.nav-toggle::after {
  display: block; width: 18px; height: 2px; background: #374151; margin: 4px auto;
}
.nav-toggle::before,
.nav-toggle::after { content: ""; }

/* buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 20px;
  border-radius: 6px;
  font-size: 14px;
  font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background .15s, border-color .15s;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--red); color: #fff; }
.btn-primary:hover { background: var(--red-hover); color: #fff; }
.btn-outline { background: var(--paper); color: var(--text); border-color: var(--line-dark); }
.btn-outline:hover { border-color: #9ca3af; color: var(--text); }
.btn-sm { padding: 7px 14px; font-size: 13px; }
.btn-lg { padding: 12px 28px; font-size: 15px; }
.btn.disabled { opacity: .55; pointer-events: none; cursor: default; }

/* main sections */
.site-main { min-height: calc(100vh - 220px); }

.page-head {
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  padding: 32px 0 28px;
}
.page-head h1 { font-size: 26px; font-weight: 700; margin-bottom: 8px; }
.page-head p { color: var(--muted); font-size: 15px; max-width: 640px; }

.section { padding: 36px 0; }
.section-title {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 18px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--line);
}

/* home hero */
.hero {
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  padding: 48px 0 40px;
}
.hero-inner {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 40px;
  align-items: center;
}
.hero--featured {
  padding: 36px 0 32px;
}
.hero--featured > .wrap {
  max-width: 1120px;
}
.hero--featured .hero-inner {
  grid-template-columns: 0.88fr 1.12fr;
  gap: 32px;
  align-items: center;
}
.hero-mockup {
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid #d1d5db;
  background: #fff;
  box-shadow: 0 8px 28px rgba(16, 24, 40, 0.1), 0 2px 6px rgba(16, 24, 40, 0.06);
}
.hero-mockup-bar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 9px 12px;
  background: linear-gradient(180deg, #fafbfc 0%, #f3f4f6 100%);
  border-bottom: 1px solid var(--line);
}
.hero-mockup-bar span {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  flex-shrink: 0;
}
.hero-mockup-bar span:nth-child(1) { background: #fca5a5; }
.hero-mockup-bar span:nth-child(2) { background: #fcd34d; }
.hero-mockup-bar span:nth-child(3) { background: #86efac; }
.hero-mockup-bar em {
  margin-left: 6px;
  font-style: normal;
  font-size: 12px;
  color: #6b7280;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.hero-mockup-shot {
  display: block;
  width: 100%;
  margin: 0;
  padding: 0;
  border: 0;
  cursor: zoom-in;
  background: #eef0f3;
  line-height: 0;
}
.hero-mockup-shot img {
  width: 100%;
  height: auto;
  display: block;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  object-position: top center;
  image-rendering: auto;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
}
.hero-mockup-hint {
  margin: 0;
  padding: 8px 12px;
  font-size: 12px;
  color: #9ca3af;
  text-align: center;
  background: #fafbfc;
  border-top: 1px solid var(--line);
}
.hero-showcase {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
  background: #f3f4f6;
  box-shadow: var(--shadow);
}
.hero-showcase img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
  object-position: top center;
}
.hero-zoom-dialog {
  position: relative;
  width: min(96vw, 1280px);
  max-height: 92vh;
  padding: 0;
  border: none;
  border-radius: 10px;
  overflow: hidden;
  background: #111;
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.35);
}
.hero-zoom-dialog::backdrop {
  background: rgba(15, 18, 28, 0.72);
}
.hero-zoom-dialog img {
  width: 100%;
  height: auto;
  max-height: calc(92vh - 48px);
  display: block;
  object-fit: contain;
  background: #111;
}
.hero-zoom-close {
  position: absolute;
  top: 10px;
  right: 12px;
  z-index: 2;
  width: 36px;
  height: 36px;
  border: none;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.92);
  color: #374151;
  font-size: 22px;
  line-height: 1;
  cursor: pointer;
}
.hero-zoom-close:hover { background: #fff; }
.hero--featured h1 {
  font-size: 30px;
  line-height: 1.25;
}
.hero--split {
  padding: 0;
  border-bottom: none;
  background: #fff;
}
.hero-split-layout {
  display: grid;
  grid-template-columns: minmax(420px, 500px) 1fr;
  min-height: min(78vh, 680px);
  max-height: 760px;
  width: 100%;
}
.hero-copy-panel {
  display: flex;
  align-items: center;
  padding: 56px 48px;
  background: #fff;
  border-right: 1px solid var(--line);
  z-index: 2;
  min-width: 0;
}
.hero-copy-panel .hero-copy {
  max-width: 420px;
  width: 100%;
}
.hero-image-panel {
  background-color: #f3f4f6;
  background-size: cover;
  background-position: center top;
  background-repeat: no-repeat;
  min-height: 420px;
}
.hero--split h1 {
  font-size: clamp(28px, 3.6vw, 42px);
  line-height: 1.2;
  margin-bottom: 14px;
}
.hero--split .hero-lead {
  font-size: clamp(15px, 1.8vw, 18px);
  color: #1f2937;
}
.hero--split .hero-note {
  font-size: 14px;
  margin-bottom: 28px;
}
.hero--bg {
  position: relative;
  padding: 0;
  border-bottom: none;
  overflow: hidden;
  background: #1a1d26;
}
.hero-bg-layer {
  position: absolute;
  inset: 0;
  background-image: var(--hero-bg);
  background-size: cover;
  background-position: center right;
  background-repeat: no-repeat;
}
.hero-bg-layer::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    100deg,
    rgba(255, 255, 255, 0.98) 0%,
    rgba(255, 255, 255, 0.94) 34%,
    rgba(255, 255, 255, 0.72) 52%,
    rgba(255, 255, 255, 0.28) 72%,
    rgba(255, 255, 255, 0.08) 100%
  );
}
.hero--bg > .wrap {
  max-width: 1240px;
}
.hero-inner--bg {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  min-height: min(72vh, 640px);
  padding: 56px 20px;
}
.hero-copy {
  max-width: 560px;
}
.hero--bg h1 {
  font-size: clamp(32px, 4.2vw, 46px);
  line-height: 1.2;
  margin-bottom: 14px;
}
.hero--bg .hero-lead {
  font-size: clamp(16px, 2vw, 19px);
  color: #1f2937;
}
.hero--bg .hero-note {
  font-size: 15px;
  margin-bottom: 28px;
}
.hero h1 { font-size: 32px; line-height: 1.3; margin-bottom: 12px; font-weight: 700; }
.hero-lead { font-size: 16px; color: #374151; margin-bottom: 8px; }
.hero-note { font-size: 14px; color: var(--muted); margin-bottom: 24px; }
.hero-btns { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 20px; }
.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  font-size: 13px;
  color: var(--muted);
}
.hero-meta strong { color: var(--text); }

.hero-panel {
  background: #fafbfc;
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
}
.hero-panel-head {
  padding: 10px 14px;
  background: #eef0f3;
  border-bottom: 1px solid var(--line);
  font-size: 12px;
  color: var(--muted);
}
.hero-panel-body { padding: 16px; }
.stat-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-bottom: 14px;
}
.stat-box {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 12px;
  text-align: center;
}
.stat-box b { display: block; font-size: 18px; color: var(--red); margin-bottom: 2px; }
.stat-box span { font-size: 12px; color: var(--muted); }
.flow-list { list-style: none; font-size: 13px; }
.flow-list li {
  padding: 8px 0;
  border-top: 1px dashed var(--line);
  display: flex;
  gap: 8px;
}
.flow-list li:first-child { border-top: none; }
.flow-num {
  width: 20px; height: 20px;
  background: var(--red-soft);
  color: var(--red);
  border-radius: 4px;
  font-size: 12px;
  font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}

/* cards & grids */
.card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 20px 22px;
  box-shadow: var(--shadow);
}
.card-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}
.card h3 { font-size: 15px; margin-bottom: 8px; }
.card p { font-size: 14px; color: var(--muted); }

.three-col {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

/* download page */
.download-box {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 20px;
  align-items: start;
}
.dl-main { }
.dl-side .card { position: sticky; top: 80px; }
.dl-version {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 4px;
}
.dl-date { font-size: 13px; color: var(--muted); margin-bottom: 18px; }
.spec-table { width: 100%; border-collapse: collapse; font-size: 14px; }
.spec-table th,
.spec-table td {
  padding: 10px 12px;
  border: 1px solid var(--line);
  text-align: left;
}
.spec-table th { background: #f9fafb; width: 140px; font-weight: 600; color: #374151; }
.changelog {
  background: #f9fafb;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 16px 18px;
  font-size: 14px;
  color: #374151;
  white-space: pre-wrap;
  line-height: 1.7;
}
.install-steps { counter-reset: step; list-style: none; }
.install-steps li {
  counter-increment: step;
  padding: 14px 0 14px 36px;
  border-bottom: 1px solid var(--line);
  position: relative;
  font-size: 14px;
}
.install-steps li::before {
  content: counter(step);
  position: absolute;
  left: 0; top: 14px;
  width: 24px; height: 24px;
  background: var(--red);
  color: #fff;
  border-radius: 4px;
  font-size: 13px;
  font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}
.install-steps li:last-child { border-bottom: none; }

/* features */
.feature-block {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 24px;
  padding: 24px 0;
  border-bottom: 1px solid var(--line);
}
.feature-block:last-child { border-bottom: none; }
.feature-label {
  font-size: 13px;
  color: var(--muted);
  padding-top: 4px;
}
.feature-label b { display: block; font-size: 17px; color: var(--text); margin-bottom: 4px; }
.feature-body p { margin-bottom: 10px; font-size: 14px; color: #4b5563; }
.feature-body ul { margin: 0 0 0 18px; font-size: 14px; color: #4b5563; }
.feature-body li { margin-bottom: 6px; }

/* guide */
.step-card {
  display: flex;
  gap: 16px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}
.step-card:last-child { border-bottom: none; }
.step-badge {
  width: 32px; height: 32px;
  background: var(--red);
  color: #fff;
  border-radius: 6px;
  font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.step-card h3 { font-size: 15px; margin-bottom: 6px; }
.step-card p { font-size: 14px; color: var(--muted); }

.faq-item {
  border: 1px solid var(--line);
  border-radius: 6px;
  margin-bottom: 10px;
  background: var(--paper);
  overflow: hidden;
}
.faq-q {
  padding: 14px 16px;
  font-weight: 600;
  font-size: 14px;
  background: #fafbfc;
  border-bottom: 1px solid var(--line);
}
.faq-a { padding: 14px 16px; font-size: 14px; color: #4b5563; }

/* screenshots */
.shot-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
}
.shot-item {
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
  background: var(--paper);
}
.shot-item img { width: 100%; display: block; aspect-ratio: 16/10; object-fit: cover; background: #eee; }
.shot-item figcaption { padding: 10px 12px; font-size: 13px; color: var(--muted); }

/* purchase */
.purchase-wrap { max-width: 520px; }
.purchase-price {
  font-size: 28px;
  font-weight: 700;
  color: var(--red);
  margin: 12px 0;
}
.purchase-line { font-size: 14px; margin-bottom: 8px; color: #374151; }
.purchase-note { font-size: 13px; color: var(--muted); margin: 16px 0 20px; line-height: 1.7; }
.tip-box {
  margin-top: 24px;
  padding: 14px 16px;
  background: #fffbeb;
  border: 1px solid #fde68a;
  border-radius: 6px;
  font-size: 13px;
  color: #92400e;
}

/* footer */
.site-footer {
  background: #2b2f3a;
  color: #c5c9d4;
  margin-top: 40px;
  font-size: 13px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 28px;
  padding: 36px 0 28px;
}
.footer-brand { font-weight: 600; color: #fff; margin: 8px 0 4px; }
.footer-desc { color: #9ca3af; line-height: 1.6; }
.footer-col h4 { color: #e5e7eb; font-size: 13px; margin-bottom: 10px; }
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 6px; }
.footer-col a { color: #c5c9d4; }
.footer-col a:hover { color: #fff; }
.footer-col .muted { color: #9ca3af; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 14px 0;
  text-align: center;
  color: #9ca3af;
  font-size: 12px;
}

.site-footer .footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 14px 0;
  text-align: center;
  color: #9ca3af;
  font-size: 12px;
}

/* hero PC screenshot */
.hero-visual { min-width: 0; }
.hero-shot {
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
  background: var(--paper);
  box-shadow: var(--shadow);
}
.hero-shot img { width: 100%; display: block; aspect-ratio: 16/10; object-fit: cover; background: #e5e7eb; }
.hero-shot figcaption { padding: 10px 12px; font-size: 13px; color: var(--muted); text-align: center; }

/* value proposition */
.section-value { background: #fff; border-bottom: 1px solid var(--line); }
.value-lead { font-size: 15px; color: #374151; line-height: 1.75; margin: -8px 0 20px; max-width: 820px; }
.value-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; margin-bottom: 20px; }
.value-card h3 { font-size: 15px; color: var(--red); margin-bottom: 8px; }
.value-card p { font-size: 14px; color: #4b5563; }
.flow-chain { text-align: center; padding: 22px; }
.flow-chain h3 { font-size: 15px; margin-bottom: 14px; }
.chain-steps { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: 8px; font-size: 14px; font-weight: 600; color: #374151; }
.chain-steps em { color: var(--red); font-style: normal; }

/* core dual-end section */
.section-core { padding-top: 0; }
.core-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.core-card { position: relative; }
.core-card-main { border-color: #f5c2cb; background: #fffafb; }
.core-tag {
  display: inline-block; font-size: 11px; font-weight: 600;
  padding: 2px 8px; border-radius: 4px; background: #f3f4f6; color: #6b7280; margin-bottom: 8px;
}
.core-tag-hot { background: var(--red-soft); color: var(--red); }
.core-card h3 { font-size: 16px; margin-bottom: 8px; }
.core-card p { font-size: 14px; color: var(--muted); margin-bottom: 10px; }
.core-card a { font-size: 13px; font-weight: 600; }

/* bitbrowser section */
.section-bitbrowser { background: #fafbfc; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.bitbrowser-head {
  display: grid; grid-template-columns: 1fr 260px; gap: 20px; align-items: start; margin-bottom: 20px;
}
.tag-core {
  display: inline-block; font-size: 12px; font-weight: 600; color: var(--red);
  background: var(--red-soft); padding: 3px 10px; border-radius: 4px; margin-bottom: 10px;
}
.section-title.left { text-align: left; border: none; margin-bottom: 8px; padding-bottom: 0; }
.bitbrowser-summary { font-size: 15px; color: #374151; margin-bottom: 8px; max-width: 560px; }
.bitbrowser-ext { font-size: 14px; color: var(--muted); }
.bitbrowser-dl h3 { font-size: 15px; margin-bottom: 6px; }
.bitbrowser-dl p { font-size: 13px; color: var(--muted); margin-bottom: 12px; }
.muted-sm { font-size: 12px; color: var(--muted); margin-top: 10px; margin-bottom: 0; }
.wait-tips { margin-top: 16px; }
.wait-tips h3 { font-size: 15px; margin-bottom: 10px; }
.wait-tips ul { margin: 0 0 0 18px; font-size: 14px; color: #4b5563; }
.wait-tips li { margin-bottom: 8px; }

.feature-block-highlight { background: #fffafb; margin: -20px -22px 0; padding: 20px 22px; border-radius: 8px 8px 0 0; border-bottom: 1px solid #fce8ec; }

/* videos */
.video-grid { display: grid; gap: 20px; }
.video-card h3 { font-size: 16px; margin-bottom: 6px; }
.video-desc { font-size: 14px; color: var(--muted); margin-bottom: 12px; }
.video-frame {
  position: relative; width: 100%; aspect-ratio: 16/9; background: #111; border-radius: 6px; overflow: hidden;
}
.video-frame video, .video-frame iframe { width: 100%; height: 100%; border: 0; display: block; }
.video-placeholder { text-align: center; color: var(--muted); font-size: 14px; padding: 32px 20px; }

@media (max-width: 860px) {
  .hero-inner,
  .hero--featured .hero-inner,
  .download-box,
  .card-grid,
  .three-col,
  .core-grid,
  .value-grid,
  .bitbrowser-head,
  .feature-block,
  .footer-grid { grid-template-columns: 1fr; }
  .stat-row { grid-template-columns: 1fr; }
  .dl-side .card { position: static; }
  .nav-toggle { display: block; }
  .site-nav {
    display: none;
    position: absolute;
    left: 0; right: 0; top: 60px;
    background: var(--paper);
    border-bottom: 1px solid var(--line);
    padding: 12px 20px;
  }
  body.nav-open .site-nav { display: block; }
  .site-nav ul { flex-direction: column; }
  .header-cta { display: none; }
  .header-row { position: relative; flex-wrap: wrap; }
  .hero-showcase img { max-height: none; }
  .hero-mockup-shot img { aspect-ratio: 16 / 11; }
  .hero-mockup-hint { display: none; }
  .hero-split-layout {
    grid-template-columns: 1fr;
    max-height: none;
  }
  .hero-copy-panel {
    padding: 36px 20px 28px;
    border-right: none;
    border-bottom: 1px solid var(--line);
  }
  .hero-image-panel {
    min-height: 240px;
    aspect-ratio: 16 / 10;
  }
  .hero--bg .hero-bg-layer {
    background-position: center center;
  }
  .hero--bg .hero-bg-layer::after {
    background: linear-gradient(
      180deg,
      rgba(255, 255, 255, 0.96) 0%,
      rgba(255, 255, 255, 0.92) 55%,
      rgba(255, 255, 255, 0.75) 100%
    );
  }
  .hero-inner--bg {
    min-height: auto;
    padding: 40px 20px 48px;
  }
  .hero-copy { max-width: none; }
}