:root {
  --blue: #1d64f2;
  --blue-dark: #1148c7;
  --cyan: #16b8e6;
  --ink: #172033;
  --muted: #647086;
  --line: #dbe5f4;
  --soft: #f4f8ff;
  --white: #ffffff;
  --green: #16a36c;
  --red: #d93f3f;
  --shadow: 0 20px 60px rgba(29, 100, 242, 0.14);
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  color: var(--ink);
  background: #fbfdff;
  line-height: 1.6;
}
a { color: inherit; text-decoration: none; }
input, button, textarea, select { font: inherit; }

.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  max-width: 1180px;
  margin: 0 auto;
  padding: 18px 22px;
  background: rgba(251, 253, 255, 0.88);
  backdrop-filter: blur(14px);
}
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; }
.brand-mark {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--blue), var(--cyan));
  color: white;
  font-size: 14px;
}
.nav nav { display: flex; align-items: center; gap: 22px; color: var(--muted); font-size: 14px; }
.nav nav a:hover { color: var(--blue); }

.hero {
  max-width: 1180px;
  margin: 0 auto;
  min-height: 620px;
  display: grid;
  grid-template-columns: 1.08fr 0.92fr;
  align-items: center;
  gap: 56px;
  padding: 52px 22px 70px;
}
.eyebrow {
  color: var(--blue);
  font-weight: 800;
  margin: 0 0 16px;
}
h1, h2, h3, p { margin-top: 0; }
.hero h1 {
  font-size: 58px;
  line-height: 1.08;
  margin-bottom: 22px;
}
.lead {
  color: var(--muted);
  font-size: 19px;
  max-width: 680px;
}
.signup-card {
  margin: 30px 0 18px;
  display: flex;
  gap: 12px;
  max-width: 600px;
  padding: 10px;
  background: white;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}
.signup-card input {
  flex: 1;
  min-width: 0;
  border: 0;
  outline: 0;
  padding: 12px 14px;
}
.signup-card button, .btn {
  border: 0;
  border-radius: 8px;
  padding: 12px 18px;
  cursor: pointer;
  font-weight: 800;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
}
.btn.primary, .signup-card button { background: var(--blue); color: white; }
.btn.primary:hover, .signup-card button:hover { background: var(--blue-dark); }
.btn.ghost { border: 1px solid var(--line); color: var(--ink); background: white; }
.btn.light { background: white; color: var(--blue); }
.btn.block { width: 100%; }
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }

.network-panel {
  position: relative;
  overflow: hidden;
  min-height: 450px;
  border-radius: 8px;
  background:
    radial-gradient(circle at 70% 18%, rgba(22,184,230,.28), transparent 32%),
    linear-gradient(145deg, #0d3fb4, #1f7df5 58%, #10b7de);
  color: white;
  padding: 32px;
  box-shadow: 0 32px 80px rgba(29, 100, 242, .28);
}
.network-panel::before {
  content: "";
  position: absolute;
  inset: 70px 34px 120px;
  border: 1px solid rgba(255,255,255,.26);
  border-radius: 50%;
  transform: rotate(-16deg);
}
.network-panel::after {
  content: "";
  position: absolute;
  right: 64px;
  bottom: 92px;
  width: 170px;
  height: 170px;
  border-radius: 50%;
  border: 1px solid rgba(255,255,255,.22);
}
.panel-top, .speed, .network-panel p, .routes { position: relative; z-index: 1; }
.panel-top { display: flex; justify-content: space-between; align-items: center; }
.panel-top strong { background: rgba(255,255,255,.18); padding: 6px 12px; border-radius: 999px; }
.speed { margin-top: 92px; font-size: 92px; font-weight: 900; line-height: 1; }
.speed span { font-size: 24px; margin-left: 8px; }
.network-panel p { max-width: 340px; opacity: .9; }
.routes { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 42px; }
.routes span { background: rgba(255,255,255,.16); padding: 8px 12px; border-radius: 999px; }

.stats, .section, .keywords, .guide, .faq, .dashboard, .auth-wrap {
  max-width: 1180px;
  margin: 0 auto;
  padding-left: 22px;
  padding-right: 22px;
}
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 88px;
}
.stats div, .feature-grid article, .plan, .tool-card, .account-grid article, .auth-box {
  background: white;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 12px 40px rgba(23, 32, 51, .06);
}
.stats div { padding: 22px; }
.stats strong { display: block; font-size: 30px; color: var(--blue); }
.stats span, .muted { color: var(--muted); }
.section { padding-top: 20px; padding-bottom: 80px; }
.section-title { max-width: 760px; margin-bottom: 30px; }
.section-title p { color: var(--blue); font-weight: 800; }
.section-title h2, .guide h2, .faq h2, .keywords h2 { font-size: 34px; line-height: 1.2; }
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}
.feature-grid article { padding: 24px; }
.feature-grid span { color: var(--blue); font-weight: 900; }
.feature-grid h3 { margin: 14px 0 10px; }
.feature-grid p, .plan li, .guide p, .faq p, .tool-card p { color: var(--muted); }

.keywords {
  margin-bottom: 80px;
  padding-top: 34px;
  padding-bottom: 34px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.keywords p { color: var(--muted); max-width: 860px; }
.keywords div { display: flex; flex-wrap: wrap; gap: 10px; }
.keywords span {
  background: var(--soft);
  color: #255182;
  border: 1px solid #d6e7ff;
  border-radius: 999px;
  padding: 8px 12px;
  font-size: 14px;
}

.plan-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.plan { padding: 26px; position: relative; }
.plan.highlighted {
  background: linear-gradient(145deg, var(--blue), var(--cyan));
  color: white;
  border-color: transparent;
}
.plan.highlighted li { color: rgba(255,255,255,.86); }
.price { font-size: 34px; font-weight: 900; margin: 18px 0; }
.price span { font-size: 15px; color: inherit; opacity: .72; }
.plan ul { padding-left: 20px; min-height: 104px; }
.badge { position: absolute; top: 18px; right: 18px; background: rgba(255,255,255,.18); padding: 5px 10px; border-radius: 999px; font-size: 13px; }

.guide { padding-bottom: 82px; }
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.steps div { border-left: 4px solid var(--blue); background: var(--soft); padding: 24px; border-radius: 8px; }
.steps b { color: var(--blue); font-size: 28px; }
.faq { padding-bottom: 80px; }
details { background: white; border: 1px solid var(--line); border-radius: 8px; padding: 18px 20px; margin-bottom: 12px; }
summary { cursor: pointer; font-weight: 800; }
.article-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.article-card {
  display: block;
  background: white;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 22px;
  box-shadow: 0 12px 40px rgba(23, 32, 51, .06);
}
.article-card span { color: var(--blue); font-weight: 800; font-size: 13px; }
.article-card h2 { font-size: 20px; line-height: 1.3; margin: 10px 0; }
.article-card p { color: var(--muted); margin-bottom: 0; }
.article-detail {
  max-width: 860px;
  margin: 0 auto;
  padding: 54px 22px 80px;
}
.article-detail h1 { font-size: 42px; line-height: 1.18; }
.article-content {
  color: #243149;
  font-size: 17px;
}
.article-content h2 { margin-top: 34px; font-size: 26px; }
.article-content p { color: #43506a; }
.article-content ul { padding-left: 22px; color: #43506a; }
.article-cta {
  margin-top: 34px;
  padding: 22px;
  border-radius: 8px;
  background: var(--soft);
  border: 1px solid var(--line);
  display: grid;
  gap: 10px;
}
.article-cta span { color: var(--muted); }

.auth-wrap { min-height: 620px; display: grid; place-items: center; }
.auth-box { width: min(100%, 480px); padding: 30px; }
label { display: block; font-weight: 800; margin: 14px 0 8px; }
input, textarea, select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px 14px;
  outline: 0;
  background: white;
}
input:focus, textarea:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(29,100,242,.12); }
.alert { padding: 12px 14px; border-radius: 8px; margin-bottom: 16px; background: #eaf7f1; color: var(--green); border: 1px solid #c8eddd; }
.alert.error { background: #fff0f0; color: var(--red); border-color: #ffd0d0; }

.dashboard { padding-top: 36px; padding-bottom: 80px; }
.dash-hero, .admin-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  margin-bottom: 18px;
}
.dash-hero h1 { font-size: 34px; margin-bottom: 8px; }
.account-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 16px;
}
.account-grid article { padding: 22px; }
.account-grid span { color: var(--muted); }
.account-grid strong { display: block; margin: 8px 0; font-size: 28px; color: var(--blue); }
.dashboard-ad {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 14px;
  margin: 0 0 16px;
  padding: 18px 20px;
  border-radius: 8px;
  background: linear-gradient(135deg, #10213e, #1d64f2);
  color: white;
  box-shadow: var(--shadow);
}
.dashboard-ad span {
  background: rgba(255,255,255,.16);
  border: 1px solid rgba(255,255,255,.22);
  border-radius: 999px;
  padding: 6px 10px;
  font-size: 13px;
}
.dashboard-ad strong { font-size: 18px; }
.dashboard-ad em {
  font-style: normal;
  background: white;
  color: var(--blue);
  border-radius: 8px;
  padding: 8px 12px;
  font-weight: 800;
}
.tool-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
.tool-card { padding: 24px; }
.tool-card.wide { grid-column: 1 / -1; }
.stack { display: flex; flex-wrap: wrap; gap: 10px; }
.copyline { display: flex; gap: 10px; }
.copyline input { flex: 1; min-width: 0; }

.admin-shell { min-height: 100vh; display: grid; grid-template-columns: 250px 1fr; }
.admin-side {
  background: #10213e;
  color: white;
  padding: 22px;
}
.admin-side .brand { margin-bottom: 26px; }
.admin-side nav { display: grid; gap: 8px; }
.admin-side nav a { padding: 11px 12px; border-radius: 8px; color: rgba(255,255,255,.78); }
.admin-side nav a:hover { background: rgba(255,255,255,.1); color: white; }
.admin-main { padding: 28px; min-width: 0; }
.table-wrap { overflow-x: auto; background: white; border: 1px solid var(--line); border-radius: 8px; }
table { width: 100%; border-collapse: collapse; min-width: 860px; }
th, td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-size: 13px; background: var(--soft); }
td form { display: flex; gap: 8px; flex-wrap: wrap; }
td button { border: 1px solid var(--line); background: white; border-radius: 8px; padding: 7px 10px; cursor: pointer; }
.admin-form, .settings-form { display: grid; gap: 14px; }
.form-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }

.footer {
  max-width: 1180px;
  margin: 0 auto;
  padding: 34px 22px 46px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  gap: 24px;
  color: var(--muted);
}
.footer strong { color: var(--ink); }

@media (max-width: 900px) {
  .nav { align-items: flex-start; }
  .nav nav { display: none; }
  .hero { grid-template-columns: 1fr; min-height: auto; padding-top: 30px; gap: 28px; }
  .hero h1 { font-size: 40px; }
  .network-panel { min-height: 360px; }
  .stats, .feature-grid, .plan-grid, .steps, .account-grid, .tool-grid, .article-list { grid-template-columns: 1fr; }
  .dashboard-ad { grid-template-columns: 1fr; }
  .tool-card.wide { grid-column: auto; }
  .signup-card, .copyline, .dash-hero, .admin-top, .footer { flex-direction: column; align-items: stretch; }
  .admin-shell { grid-template-columns: 1fr; }
  .admin-side { position: static; }
  .admin-side nav { grid-template-columns: repeat(2, 1fr); }
  .admin-main { padding: 20px; }
  .form-grid { grid-template-columns: 1fr; }
}