/* Google Chrome 产品说明书风：白底 + 官方四色，系统字体，圆角 12px */

:root {
  --blue: #1A73E8;
  --red: #EA4335;
  --yellow: #FBBC05;
  --green: #34A853;
  --ink: #202124;
  --muted: #5f6368;
  --line: #e8eaed;
  --paper: #ffffff;
  --wash: #f8fbff;
  --hero-a: #eef4fc;
  --hero-b: #f6f8fb;
  --navy: #174ea6;
  --navy-deep: #0b1f3a;
  --radius: 12px;
  --max: 1080px;
  --header-h: 64px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: auto;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.75;
}

img,
svg {
  vertical-align: middle;
}

a {
  color: var(--blue);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

a:hover {
  color: #1558b0;
}

h1,
h2,
h3 {
  line-height: 1.35;
  font-weight: 650;
  color: var(--ink);
}

h1 {
  font-size: clamp(1.7rem, 2.4vw + 1rem, 2.35rem);
  margin: 0 0 16px;
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.25rem, 1.2vw + 1rem, 1.55rem);
  margin: 0 0 14px;
}

h3 {
  font-size: 1.05rem;
  margin: 0 0 10px;
}

p {
  margin: 0 0 14px;
  color: var(--ink);
}

p:last-child {
  margin-bottom: 0;
}

.wrap {
  width: min(var(--max), calc(100% - 40px));
  margin: 0 auto;
}

/* 顶栏：sticky 白底细线 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

.brand-stripe {
  display: flex;
  height: 3px;
}

.brand-stripe span {
  flex: 1;
}

.brand-stripe span:nth-child(1) { background: var(--blue); }
.brand-stripe span:nth-child(2) { background: var(--red); }
.brand-stripe span:nth-child(3) { background: var(--yellow); }
.brand-stripe span:nth-child(4) { background: var(--green); }

.header-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.brand:hover {
  color: var(--ink);
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 6px 4px;
}

.site-nav a {
  display: inline-block;
  padding: 8px 12px;
  color: var(--muted);
  text-decoration: none;
  border-radius: 8px;
  font-size: 14px;
}

.site-nav a:hover {
  color: var(--blue);
  background: var(--wash);
}

.site-nav a.is-current,
.site-nav a[aria-current="page"] {
  color: var(--blue);
  background: #e8f0fe;
  font-weight: 650;
}

/* Hero：全宽浅灰蓝渐变，居中 */
.hero {
  position: relative;
  overflow: hidden;
  background: linear-gradient(180deg, var(--hero-a) 0%, var(--hero-b) 58%, #ffffff 100%);
  border-bottom: 1px solid var(--line);
  text-align: center;
  padding: 64px 0 48px;
}

.hero-orbit {
  position: absolute;
  width: 220px;
  height: 220px;
  border: 2px dashed rgba(26, 115, 232, 0.22);
  border-radius: 50%;
  top: 28px;
  right: 8%;
  animation: spin 22s linear infinite;
  pointer-events: none;
}

.hero-orbit::after {
  content: "";
  position: absolute;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--blue);
  top: -7px;
  left: 50%;
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.kicker {
  display: inline-block;
  margin-bottom: 12px;
  padding: 4px 10px;
  border: 1px solid #c9d8f0;
  border-radius: 999px;
  color: var(--blue);
  background: rgba(255, 255, 255, 0.7);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.lede {
  max-width: 720px;
  margin: 0 auto 22px;
  color: var(--muted);
  font-size: 17px;
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-bottom: 28px;
}

button {
  font-family: inherit;
  cursor: pointer;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 48px;
  padding: 10px 22px;
  border: 0;
  border-radius: var(--radius);
  font-size: 16px;
  font-weight: 650;
}

.btn-primary {
  color: #fff;
  background: var(--blue);
  box-shadow: 0 8px 20px rgba(26, 115, 232, 0.2);
}

a.btn-primary,
a.btn-primary:hover {
  color: #fff;
  text-decoration: none;
}

.btn-primary:hover {
  background: #1558b0;
}

.btn-ghost {
  color: var(--ink);
  background: #fff;
  border: 1px solid var(--line);
}

a.btn-ghost,
a.btn-ghost:hover {
  color: var(--ink);
  text-decoration: none;
}

.btn-ghost:hover {
  border-color: #c5cdd6;
}

.btn-green {
  color: #fff;
  background: var(--green);
}

.btn-green:hover {
  background: #2c8e46;
}

.btn-mac {
  color: var(--ink);
  background: #fff;
  border: 1px solid #dadce0;
}

.trust-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  max-width: 880px;
  margin: 0 auto;
  text-align: left;
}

.trust-item {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 12px 12px 12px 10px;
  background: rgba(255, 255, 255, 0.86);
  border: 1px solid #e3e8ef;
  border-radius: var(--radius);
}

.trust-item p {
  margin: 0;
  font-size: 13px;
  color: var(--muted);
  line-height: 1.5;
}

.trust-item strong {
  display: block;
  color: var(--ink);
  font-size: 13px;
}

/* 说明书章节骨架 */
.block {
  padding: 56px 0;
}

.block + .block {
  border-top: 1px solid var(--line);
}

.block-head {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 16px;
  margin-bottom: 22px;
  align-items: start;
}

.idx {
  font-size: 28px;
  font-weight: 700;
  color: var(--blue);
  letter-spacing: -0.04em;
  line-height: 1.15;
}

.block-head p {
  color: var(--muted);
  margin: 0;
}

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

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}

.card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 18px 18px;
}

.card h3 {
  display: flex;
  align-items: center;
  gap: 8px;
}

.card p {
  color: #3c4043;
  font-size: 15px;
}

.card-accent-b { border-top: 3px solid var(--blue); }
.card-accent-r { border-top: 3px solid var(--red); }
.card-accent-y { border-top: 3px solid var(--yellow); }
.card-accent-g { border-top: 3px solid var(--green); }

.platform-card {
  display: flex;
  flex-direction: column;
  min-height: 100%;
}

.platform-card .btn {
  width: 100%;
  margin-top: auto;
}

.icon-box {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--wash);
  flex-shrink: 0;
}

/* 左右交替图文条 */
.strip {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 28px;
  align-items: center;
  padding: 22px 0;
}

.strip + .strip {
  border-top: 1px dashed #dce3ec;
}

.strip.reverse {
  grid-template-columns: 1fr 200px;
}

.strip.reverse .strip-visual {
  order: 2;
}

.strip-visual {
  min-height: 160px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: linear-gradient(160deg, #f3f8ff, #fff);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* 评价 */
.quote-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

blockquote.quote {
  margin: 0;
  padding: 20px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--wash);
}

blockquote.quote p {
  font-size: 15px;
  color: #3c4043;
}

blockquote.quote footer {
  margin-top: 14px;
  padding: 0;
  background: transparent;
  color: var(--muted);
  font-size: 13px;
  border: 0;
}

/* 数据背书：深蓝带宽 */
.stats-band {
  background: linear-gradient(180deg, var(--navy) 0%, #12356f 100%);
  color: #fff;
}

.stats-band .block-head p,
.stats-band h2,
.stats-band p {
  color: #e8f0fe;
}

.stats-band h2 {
  color: #fff;
}

.stats-band .idx {
  color: #8ab4f8;
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

.stat {
  padding: 18px 14px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--radius);
  background: rgba(11, 31, 58, 0.28);
}

.stat b {
  display: block;
  font-size: 1.7rem;
  letter-spacing: -0.03em;
  color: #fff;
  margin-bottom: 6px;
}

.stat span {
  color: #c4d4ef;
  font-size: 13px;
  line-height: 1.55;
}

/* 对比表 */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

table.spec {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

table.spec caption {
  caption-side: bottom;
  padding: 10px 12px;
  color: var(--muted);
  text-align: left;
  font-size: 13px;
}

table.spec th,
table.spec td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

table.spec thead th {
  background: #f1f5fb;
  color: #3c4043;
  font-weight: 650;
}

table.spec tbody th {
  width: 22%;
  color: var(--ink);
  background: #fafbfe;
}

table.spec tbody tr:last-child th,
table.spec tbody tr:last-child td {
  border-bottom: 0;
}

/* FAQ 手风琴 */
.faq-list details {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0 16px;
  background: #fff;
  margin-bottom: 10px;
}

.faq-list summary {
  cursor: pointer;
  padding: 14px 4px;
  font-weight: 650;
  color: var(--ink);
}

.faq-list details p {
  padding: 0 4px 16px;
  color: #3c4043;
  font-size: 15px;
}

/* 下载主推区 */
.download-panel {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 20px;
  align-items: stretch;
}

.panel-main {
  border: 1px solid #c9d8f0;
  border-radius: var(--radius);
  padding: 24px;
  background: linear-gradient(180deg, #f7faff, #fff);
}

.req-list,
.step-list {
  margin: 0;
  padding-left: 18px;
}

.req-list li,
.step-list li {
  margin-bottom: 10px;
  color: #3c4043;
}

.note {
  padding: 12px 14px;
  border-left: 3px solid var(--yellow);
  background: #fff8e1;
  border-radius: 0 var(--radius) var(--radius) 0;
  color: #3c4043;
  font-size: 14px;
}

.cta-banner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 22px 22px;
  border-radius: var(--radius);
  border: 1px solid #c9d8f0;
  background: #e8f0fe;
}

.cta-banner a.btn-link {
  display: inline-flex;
  align-items: center;
  min-height: 48px;
  padding: 10px 22px;
  border-radius: var(--radius);
  background: var(--blue);
  color: #fff;
  text-decoration: none;
  font-weight: 650;
}

.cta-banner a.btn-link:hover {
  background: #1558b0;
  color: #fff;
}

.prose h3 {
  margin-top: 22px;
}

/* 页脚深色两列 */
.site-footer {
  background: var(--navy-deep);
  color: #c5cdd6;
  padding: 40px 0 28px;
  border-top: 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
}

.site-footer h3 {
  color: #fff;
  font-size: 14px;
  letter-spacing: 0.04em;
  margin-bottom: 10px;
}

.site-footer p {
  color: #c5cdd6;
  font-size: 14px;
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin-top: 12px;
}

.footer-nav a {
  color: #8ab4f8;
  text-decoration: none;
  font-size: 14px;
}

.footer-nav a:hover {
  color: #fff;
}

@media (max-width: 900px) {
  .trust-row,
  .grid-3,
  .grid-4,
  .quote-grid,
  .stat-grid,
  .download-panel,
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .strip,
  .strip.reverse {
    grid-template-columns: 1fr;
  }

  .strip.reverse .strip-visual {
    order: 0;
  }

  .hero-orbit {
    right: -40px;
    opacity: 0.5;
  }
}

@media (max-width: 640px) {
  .wrap {
    width: min(var(--max), calc(100% - 28px));
  }

  .header-bar {
    flex-direction: column;
    align-items: flex-start;
    padding: 10px 0 12px;
    gap: 8px;
  }

  .trust-row,
  .grid-3,
  .grid-4,
  .quote-grid,
  .stat-grid,
  .download-panel,
  .footer-grid,
  .block-head {
    grid-template-columns: 1fr;
  }

  .hero {
    padding: 40px 0 32px;
  }

  .block {
    padding: 40px 0;
  }
}