:root {
  --bg: #f4f7fc;
  --surface: #ffffff;
  --text: #142033;
  --muted: #556376;
  --line: #d8e0ec;
  --primary: #2955c8;
  --primary-strong: #2144ad;
  --primary-soft: #f1f4ff;
  --shadow: 0 22px 45px rgba(14, 28, 63, 0.08);
  --radius: 16px;
}

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

html,
body {
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(1200px 500px at 8% -10%, #eef2ff, transparent),
    radial-gradient(900px 520px at 92% 0%, #f6f8ff, transparent),
    var(--bg);
  line-height: 1.6;
  letter-spacing: 0;
}

h1,
h2,
h3 {
  margin: 0;
  line-height: 1.25;
}

a {
  color: inherit;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: -9999px;
}

.skip-link:focus {
  left: 12px;
  top: 8px;
  z-index: 999;
  padding: 8px 10px;
  background: #fff;
  border: 2px solid var(--primary);
}

.container {
  width: min(1120px, calc(100% - 48px));
  margin: 0 auto;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  border-bottom: 1px solid rgba(35, 51, 90, 0.12);
  background: rgb(252 255 255 / 88%);
  backdrop-filter: blur(10px);
}

.topbar-inner {
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

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

.brand-mark {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border-radius: 10px;
  color: #fff;
  background: linear-gradient(135deg, var(--primary), var(--primary-strong));
}

.brand-name {
  font-size: 15px;
}

.brand-tag {
  font-size: 11px;
  margin-left: 2px;
  border: 1px solid #d4def7;
  border-radius: 999px;
  padding: 2px 8px;
  background: #f2f6ff;
  color: #284da2;
  font-weight: 600;
}

nav {
  display: inline-flex;
  gap: 12px;
}

nav a {
  color: #2e3b52;
  text-decoration: none;
  font-size: 14px;
  padding: 8px 12px;
}

nav a:hover {
  color: var(--primary-strong);
}

.menu-cta {
  border: 1px solid var(--primary);
  border-radius: 10px;
}

.menu-disabled {
  pointer-events: none;
  color: #95a2be;
  background: #eef2fb;
  border-color: #d6dfef;
  cursor: not-allowed;
}

.menu-disabled:hover {
  color: #95a2be;
}

.section {
  padding: 54px 0;
}

.hero {
  padding-top: 42px;
}

.hero-layout {
  display: grid;
  grid-template-columns: 1.12fr 0.88fr;
  gap: 22px;
}

.hero-copy,
.hero-panel,
.feature-card,
.usage-step,
.permission-grid article,
.cta-card,
.note-box {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.hero-copy {
  padding: 28px;
  box-shadow: var(--shadow);
}

.eyebrow,
.section-kicker,
.panel-kicker,
.stat-tag {
  display: inline-flex;
  align-items: center;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--primary-strong);
  font-weight: 700;
}

h1 {
  margin-top: 8px;
  font-size: clamp(32px, 4.1vw, 52px);
}

.lead {
  margin: 18px 0 0;
  color: var(--muted);
  max-width: 65ch;
  font-size: 18px;
}

.hero-badges {
  margin-top: 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.hero-badges span {
  border: 1px solid #d8e2f5;
  background: #f8faff;
  color: #3f547f;
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 12px;
}

.hero-actions {
  margin-top: 20px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.btn {
  height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  border-radius: 10px;
  padding: 0 15px;
  border: 1px solid #d3d9e8;
  font-size: 14px;
  font-weight: 600;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-disabled:hover {
  transform: none;
}

.btn-disabled {
  pointer-events: none;
  opacity: 0.7;
  background: #f2f4fb;
  color: #95a2be;
  border-color: #d5dfef;
}

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

.btn-primary:hover {
  background: var(--primary-strong);
}

.btn-secondary {
  background: #fff;
  color: var(--primary-strong);
}

.btn-secondary:hover {
  border-color: var(--primary-strong);
  color: var(--primary);
}

.btn-ghost {
  border: 1px dashed #a9b7d0;
}

.hero-panel {
  padding: 24px;
  background: linear-gradient(165deg, #fbfdff 0%, #eef3ff 100%);
  box-shadow: var(--shadow);
}

.panel-kicker {
  margin: 0;
}

.hero-panel h2 {
  margin-top: 8px;
  font-size: clamp(28px, 2.8vw, 34px);
}

.panel-desc {
  color: var(--muted);
  margin: 10px 0 0;
}

.panel-stats {
  margin-top: 14px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

.panel-stats article {
  border: 1px solid #d8e1f2;
  border-radius: 12px;
  padding: 12px 10px;
  background: rgba(255, 255, 255, 0.8);
}

.panel-stats strong {
  display: block;
  font-size: 28px;
  color: #273a66;
}

.panel-stats span {
  display: block;
  margin-top: 4px;
  color: #4f6080;
  font-size: 12px;
}

.panel-note {
  margin: 16px 0 0;
  color: #4f5c77;
  border-left: 3px solid #bad0ff;
  padding-left: 10px;
}

.panel-bullets {
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
}

.panel-bullets li {
  color: #40506f;
  font-size: 14px;
  line-height: 1.5;
  padding-left: 12px;
  position: relative;
}

.panel-bullets li::before {
  content: "•";
  position: absolute;
  left: 0;
  top: 0;
  color: #6486ea;
}

.section-head h2 {
  font-size: clamp(28px, 3.2vw, 42px);
}

.section-head p {
  color: var(--muted);
}

.section-head p + h2 {
  margin-top: 4px;
}

.feature-grid,
.permission-grid {
  margin-top: 16px;
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.feature-card {
  padding: 18px;
  box-shadow: 0 16px 30px rgba(22, 38, 74, 0.05);
}

.feature-card h3,
.usage-step h3,
.permission-grid h3,
.note-box h3 {
  font-size: 20px;
}

.feature-card p,
.usage-step p,
.permission-grid p,
.note-box p {
  color: var(--muted);
  margin: 8px 0 0;
}

.steps {
  margin-top: 14px;
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.usage-step {
  padding: 16px;
  background: var(--surface);
  min-height: 188px;
}

.step-index {
  display: inline-grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 999px;
  border: 1px solid #c7d7ff;
  background: var(--primary-soft);
  color: var(--primary);
  font-weight: 700;
  font-size: 13px;
}

.usage-step h3 {
  margin: 10px 0 0;
}

.note-box {
  margin-top: 14px;
  padding: 14px 16px;
  background: #f8faff;
}

.note-box h3 {
  margin: 0;
}

.permission-grid article {
  padding: 16px;
  background: linear-gradient(170deg, #ffffff 0%, #f8fbff 100%);
}

.section-soft {
  background: #f9fbff;
  border-top: 1px solid #dce3ef;
  border-bottom: 1px solid #dce3ef;
}

.cta {
  padding-bottom: 44px;
}

.cta-card {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  padding: 22px 22px;
  align-items: center;
  background: linear-gradient(135deg, #f1f5ff 0%, #ffffff 40%, #f8faff 100%);
  box-shadow: var(--shadow);
}

.cta p {
  color: var(--muted);
  max-width: 760px;
}

.footer {
  border-top: 1px solid var(--line);
  padding: 26px 0 36px;
  color: #6b7688;
  font-size: 13px;
}

.signup-card {
  max-width: 760px;
  margin: 0 auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  padding: 28px;
  box-shadow: var(--shadow);
}

.signup-card-wide {
  max-width: 980px;
}

.signup-copy {
  margin-top: 6px;
  margin-bottom: 16px;
  color: var(--muted);
}

.signup-layout {
  margin-top: 18px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 22px;
  align-items: start;
}

.signup-form {
  display: grid;
  gap: 14px;
}

.signup-field {
  display: grid;
  gap: 8px;
  color: #36445f;
}

.signup-field span {
  font-size: 14px;
  font-weight: 600;
}

.signup-field input,
.signup-field textarea {
  width: 100%;
  border: 1px solid #d7e0f0;
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 15px;
  color: var(--text);
  background: #fff;
  font-family: inherit;
}

.signup-field input:focus,
.signup-field textarea:focus {
  border-color: #94a9de;
  outline: none;
  box-shadow: 0 0 0 3px rgba(74, 114, 218, 0.14);
}

.signup-field textarea {
  resize: vertical;
}

.signup-feedback {
  min-height: 22px;
  margin: 0;
  color: #3e5ea7;
  font-size: 14px;
}

.signup-alt {
  margin: 16px 0 0;
  color: #66758f;
  font-size: 13px;
  line-height: 1.7;
}

.signup-wechat {
  border: 1px solid #e3e8f2;
  border-radius: 14px;
  padding: 18px;
  background: #f8fbff;
}

.signup-wechat h2 {
  margin: 0;
  font-size: 24px;
}

.signup-wechat .signup-copy {
  margin-top: 6px;
  margin-bottom: 12px;
}

.signup-qr {
  display: block;
  width: min(100%, 280px);
  height: auto;
  border: 1px solid #dbe4f5;
  border-radius: 12px;
  background: #fff;
  padding: 8px;
  margin: 0 auto;
}

code {
  background: #edf2ff;
  color: #254c9e;
  border: 1px solid #ced9f2;
  border-radius: 6px;
  padding: 1px 5px;
  font-size: 0.94em;
}

.hero,
#features,
#usage,
#permission,
.cta {
  scroll-margin-top: 84px;
}

@media (max-width: 1100px) {
  .container {
    width: min(1120px, calc(100% - 36px));
  }

  .hero-layout,
  .feature-grid,
  .permission-grid,
  .steps,
  .cta-card {
    grid-template-columns: 1fr;
  }

  .panel-stats {
    grid-template-columns: repeat(3, 1fr);
  }

  .panel-bullets li {
    font-size: 13px;
  }

  .signup-card {
    padding: 22px;
  }

  .signup-layout {
    grid-template-columns: 1fr;
  }

  .signup-qr {
    max-width: 280px;
  }
}

@media (max-width: 900px) {
  .topbar-inner {
    height: auto;
    padding: 12px 0;
    flex-wrap: wrap;
  }

  nav {
    flex-wrap: wrap;
  }

  .feature-card h3,
  .usage-step h3,
  .permission-grid h3 {
    font-size: 19px;
  }
}

@media (max-width: 620px) {
  .container {
    width: calc(100% - 24px);
  }

  .hero {
    padding-top: 24px;
  }

  .hero-actions,
  .hero-badges {
    gap: 8px;
  }

  .btn {
    width: 100%;
  }
}