:root {
  --ink: #12181f;
  --ink-2: #2c3540;
  --muted: #5b6774;
  --line: #e4e9ef;
  --bg: #ffffff;
  --soft: #f6f8fb;
  --brand: #2563eb;
  --brand-d: #1d4ed8;
  --brand-l: #eaf1ff;
  --teal: #0e9f9c;
  --radius: 14px;
  --wrap: 1120px;
  --shadow: 0 1px 2px rgba(18, 24, 31, .05), 0 8px 24px rgba(18, 24, 31, .06);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 76px; }

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

h1, h2, h3, h4 { line-height: 1.3; margin: 0 0 .6em; letter-spacing: -.01em; }
p { margin: 0 0 1em; }
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }
ul { margin: 0; padding-left: 1.1em; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 24px; }
.wrap-narrow { max-width: 780px; }

.grad {
  background: linear-gradient(96deg, var(--brand), var(--teal));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ---------- nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .88);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color .2s, box-shadow .2s;
}
.nav.stuck { border-bottom-color: var(--line); box-shadow: 0 2px 12px rgba(18, 24, 31, .05); }
.nav-inner { display: flex; align-items: center; gap: 24px; height: 68px; }

.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); }
.brand:hover { text-decoration: none; }
.seal {
  width: 34px; height: 34px; flex: 0 0 34px;
  display: grid; place-items: center;
  border-radius: 9px;
  background: linear-gradient(140deg, var(--brand), var(--teal));
  color: #fff; font-size: 19px; font-weight: 600;
  box-shadow: 0 2px 8px rgba(37, 99, 235, .28);
}
.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-text strong { font-size: 17px; letter-spacing: .06em; }
.brand-text em {
  font-style: normal; font-size: 11px; color: var(--muted);
  letter-spacing: .06em; text-transform: uppercase;
}

.nav-links { margin-left: auto; display: flex; gap: 26px; }
.nav-links a { color: var(--ink-2); font-size: 15px; }
.nav-links a:hover { color: var(--brand); text-decoration: none; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 8px; padding: 10px 18px;
  border: 1px solid transparent; border-radius: 10px;
  font-size: 15px; font-weight: 500; cursor: pointer;
  transition: background .15s, border-color .15s, transform .1s;
  white-space: nowrap;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary { background: var(--brand); color: #fff; box-shadow: 0 2px 10px rgba(37, 99, 235, .25); }
.btn-primary:hover { background: var(--brand-d); color: #fff; }
.btn-ghost { background: #fff; color: var(--ink); border-color: var(--line); }
.btn-ghost:hover { border-color: #c9d3e0; color: var(--ink); }
.btn-sm { padding: 7px 14px; font-size: 14px; }
.btn-lg { padding: 13px 26px; font-size: 16px; border-radius: 12px; }
.btn-block { display: flex; width: 100%; }
/* Windows 四色标志（内联 SVG，em 尺寸随按钮字号缩放） */
.win-ico { width: 1.15em; height: 1.15em; flex: 0 0 auto; display: inline-block; }

/* ---------- hero ---------- */
.hero { padding: 72px 0 84px; background:
  radial-gradient(900px 420px at 12% -8%, #eef4ff 0%, transparent 62%),
  radial-gradient(700px 380px at 92% 4%, #e9faf8 0%, transparent 60%); }
.hero-inner {
  display: grid; grid-template-columns: 1.05fr .95fr;
  gap: 56px; align-items: center;
}
.pill {
  display: inline-block; padding: 5px 13px; margin-bottom: 18px;
  background: #fff; border: 1px solid var(--line);
  border-radius: 999px; font-size: 13px; color: var(--muted);
}
.hero h1 { font-size: 44px; margin-bottom: 18px; letter-spacing: -.02em; }
.lede { font-size: 17.5px; color: var(--ink-2); max-width: 34em; }
.cta { display: flex; flex-wrap: wrap; gap: 12px; margin: 28px 0 22px; }
.hero-meta {
  list-style: none; padding: 0; display: flex; flex-wrap: wrap;
  gap: 8px 22px; font-size: 13.5px; color: var(--muted);
}
.hero-meta li { position: relative; padding-left: 14px; }
.hero-meta li::before {
  content: ""; position: absolute; left: 0; top: .72em;
  width: 5px; height: 5px; border-radius: 50%; background: var(--teal);
}
.hero-meta.center { justify-content: center; }

/* ---------- mock window ---------- */
.mock {
  background: #fff; border: 1px solid var(--line);
  border-radius: 16px; overflow: hidden; box-shadow: var(--shadow);
}
.mock-bar {
  display: flex; align-items: center; gap: 7px;
  padding: 11px 14px; background: #fbfcfe; border-bottom: 1px solid var(--line);
}
.dot { width: 10px; height: 10px; border-radius: 50%; background: #dbe2ec; }
.mock-title {
  margin-left: 10px; font-size: 13px; color: var(--muted);
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.mock-body { padding: 16px; }
.mock-drop {
  border: 1.5px dashed #cfd8e4; border-radius: 12px;
  padding: 20px; text-align: center; background: #fafcff;
  font-size: 14px; color: var(--ink-2);
}
.mock-drop-icon { font-size: 22px; color: var(--brand); line-height: 1; margin-bottom: 6px; }
.mock-drop small { display: block; color: var(--muted); font-size: 12px; margin-top: 4px; }
.mock-modes {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 8px; margin: 14px 0;
}
.m {
  border: 1px solid var(--line); border-radius: 10px;
  padding: 10px 6px; text-align: center; background: #fff;
  font-size: 11.5px; color: var(--ink-2); line-height: 1.4;
}
.m i { display: block; font-style: normal; font-size: 18px; margin-bottom: 3px; }
.m.active {
  border-color: var(--brand); background: var(--brand-l);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, .1);
}
.mock-prog { border: 1px solid var(--line); border-radius: 10px; padding: 12px; }
.mock-prog-row {
  display: flex; justify-content: space-between;
  font-size: 12.5px; color: var(--ink-2); margin-bottom: 7px;
}
.mock-prog-row.muted { color: var(--muted); margin: 7px 0 0; }
.bar { height: 7px; border-radius: 999px; background: #eef1f6; overflow: hidden; }
.bar i {
  display: block; height: 100%; border-radius: 999px;
  background: linear-gradient(90deg, var(--brand), var(--teal));
}

/* ---------- sections ---------- */
.sec { padding: 84px 0; }
.sec-soft { background: var(--soft); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.sec-title { font-size: 32px; text-align: center; }
.sec-sub {
  text-align: center; color: var(--muted); max-width: 46em;
  margin: 0 auto 46px; font-size: 16.5px;
}

.grid { display: grid; gap: 20px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }

.card {
  background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius); padding: 26px 24px;
  transition: transform .16s, box-shadow .16s, border-color .16s;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: #d3dce8; }
.card-ico {
  width: 44px; height: 44px; display: grid; place-items: center;
  border-radius: 11px; background: var(--brand-l); font-size: 22px; margin-bottom: 14px;
}
.card h3 { font-size: 18px; margin-bottom: 8px; }
.card p { color: var(--muted); font-size: 14.5px; margin: 0; }

.fitem {
  background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius); padding: 24px 26px;
}
.fitem h3 { font-size: 17px; margin-bottom: 8px; }
.fitem p { color: var(--muted); font-size: 14.5px; margin: 0; }

.note {
  margin-top: 30px; padding: 16px 20px;
  background: #fff; border: 1px solid var(--line);
  border-left: 3px solid var(--brand);
  border-radius: 10px; font-size: 14.5px; color: var(--ink-2);
}
.note b { color: var(--ink); }

/* ---------- steps ---------- */
.steps {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 20px; margin-top: 28px;
}
.step { display: flex; gap: 14px; align-items: flex-start; }
.step span {
  width: 30px; height: 30px; flex: 0 0 30px;
  display: grid; place-items: center;
  border-radius: 50%; background: var(--ink); color: #fff;
  font-size: 14px; font-weight: 600;
}
.step h4 { font-size: 16px; margin: 0 0 4px; }
.step p { font-size: 14px; color: var(--muted); margin: 0; }

/* ---------- pricing ---------- */
.plan {
  background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius); padding: 28px 26px;
  display: flex; flex-direction: column; position: relative;
}
.plan-hot { border-color: var(--brand); box-shadow: 0 6px 26px rgba(37, 99, 235, .12); }
.plan-badge {
  position: absolute; top: -11px; left: 26px;
  background: var(--brand); color: #fff;
  font-size: 12px; padding: 2px 11px; border-radius: 999px;
}
.plan-head { display: flex; align-items: baseline; justify-content: space-between; }
.plan h3 { font-size: 17px; margin: 0; }
.price { font-size: 30px; font-weight: 700; letter-spacing: -.02em; }
.plan-note { font-size: 13px; color: var(--muted); margin: 2px 0 16px; }
.plan ul { list-style: none; padding: 0; margin: 0 0 22px; font-size: 14.5px; color: var(--ink-2); }
.plan li { padding: 6px 0 6px 22px; position: relative; }
.plan li::before {
  content: "✓"; position: absolute; left: 0; top: 6px;
  color: var(--teal); font-size: 13px;
}
.plan .btn { margin-top: auto; }

/* ---------- faq ---------- */
.faq { border-top: 1px solid var(--line); }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary {
  padding: 18px 4px; cursor: pointer; font-size: 16.5px;
  font-weight: 500; list-style: none; position: relative;
  padding-right: 30px;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+"; position: absolute; right: 6px; top: 14px;
  color: var(--muted); font-size: 20px; font-weight: 400;
}
.faq details[open] summary::after { content: "−"; }
.faq details div { padding: 0 4px 20px; color: var(--muted); font-size: 15px; }

/* ---------- download ---------- */
.dl { text-align: center; }
.dl h2 { font-size: 32px; margin: 4px 0 12px; }
.dl > p { color: var(--muted); max-width: 34em; margin: 0 auto 28px; }
.dl-btns { display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; margin-bottom: 14px; }
.dl-tip { font-size: 14px; color: #b45309; margin: 0 0 18px; }

/* ---------- footer ---------- */
.foot { background: #0f1620; color: #9fb0c3; padding: 52px 0 30px; font-size: 14px; }
.foot-inner {
  display: flex; justify-content: space-between;
  align-items: flex-start; gap: 24px; flex-wrap: wrap;
}
.brand-foot .brand-text strong { color: #fff; }
.foot-note { margin: 10px 0 0; font-size: 13px; }
.foot-links { display: flex; gap: 22px; flex-wrap: wrap; }
.foot-links a { color: #9fb0c3; }
.foot-links a:hover { color: #fff; }
.foot-legal {
  margin-top: 34px; padding-top: 20px;
  border-top: 1px solid #1e2a38;
  display: flex; justify-content: space-between; gap: 18px; flex-wrap: wrap;
  font-size: 12.5px; color: #6f8199;
}
.foot-legal p { margin: 0; }

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; gap: 40px; }
  .hero { padding: 52px 0 60px; }
  .hero h1 { font-size: 34px; }
  .nav-links { display: none; }
  .grid-3, .grid-2, .steps { grid-template-columns: 1fr; }
  .sec { padding: 60px 0; }
  .sec-title { font-size: 26px; }
  .foot-inner { flex-direction: column; }
}
@media (max-width: 520px) {
  .hero h1 { font-size: 28px; }
  .mock-modes { grid-template-columns: repeat(2, 1fr); }
  .btn-lg { width: 100%; }
}