:root {
  --bg: #f7f8fa;
  --panel: #ffffff;
  --text: #1f2933;
  --muted: #65717f;
  --line: #e3e7ed;
  --brand: #176b87;
  --brand-dark: #0f4f63;
  --accent: #d97706;
  --soft: #eef7f8;
  --radius: 8px;
  --shadow: 0 10px 28px rgba(31, 41, 51, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
  text-decoration: none;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgba(227, 231, 237, 0.9);
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(12px);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: min(1120px, calc(100% - 32px));
  min-height: 64px;
  margin: 0 auto;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  color: #16202a;
}

.brand-mark {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  object-fit: cover;
  box-shadow: 0 3px 10px rgba(31, 41, 51, 0.14);
}

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--text);
  font-size: 22px;
  line-height: 1;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
}

.nav-links a {
  padding: 8px 12px;
  border-radius: 8px;
  color: #394756;
  font-size: 15px;
}

.nav-links a:hover,
.nav-links a.active {
  background: var(--soft);
  color: var(--brand-dark);
}

.main {
  min-height: calc(100vh - 280px);
}

.container {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
}

.hero {
  background: linear-gradient(180deg, #ffffff 0%, #f4fafb 100%);
  border-bottom: 1px solid var(--line);
}

.hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(300px, 0.9fr);
  gap: 48px;
  align-items: center;
  padding: 72px 0 60px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--brand);
  font-size: 15px;
  font-weight: 700;
}

h1,
h2,
h3 {
  margin: 0;
  color: #15212d;
  line-height: 1.35;
}

h1 {
  font-size: clamp(34px, 5vw, 54px);
  letter-spacing: 0;
}

h2 {
  margin-bottom: 18px;
  font-size: 28px;
}

h3 {
  font-size: 19px;
}

p {
  margin: 0 0 14px;
}

.hero-subtitle {
  margin-top: 12px;
  color: #354454;
  font-size: 22px;
  font-weight: 600;
}

.hero-copy {
  max-width: 660px;
  margin-top: 18px;
  color: var(--muted);
  font-size: 16px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  margin-top: 24px;
  padding: 0 20px;
  border: 1px solid var(--brand);
  border-radius: 8px;
  background: var(--brand);
  color: #fff;
  font-weight: 700;
}

.button.secondary {
  background: #fff;
  color: var(--brand-dark);
}

.phone-preview {
  width: min(100%, 360px);
  margin-left: auto;
  padding: 18px;
  border: 1px solid #dce4ea;
  border-radius: 28px;
  background: #f8fafc;
  box-shadow: var(--shadow);
}

.app-icon-hero {
  display: block;
  width: 112px;
  height: 112px;
  margin: 0 auto 18px;
  border-radius: 24px;
  box-shadow: 0 16px 36px rgba(217, 119, 6, 0.22);
}

.phone-screen {
  overflow: hidden;
  min-height: 540px;
  border: 1px solid #dfe5ec;
  border-radius: 20px;
  background: #fff;
}

.phone-shot {
  display: block;
  width: 100%;
  height: auto;
}

.app-top {
  padding: 28px 18px 24px;
  background: linear-gradient(180deg, #fff7ed 0%, #fff 100%);
  color: #fff;
  text-align: center;
}

.app-top strong {
  display: block;
  color: #8a3f08;
  font-size: 22px;
}

.app-top span {
  color: #7c5b42;
}

.quiz-card {
  margin: 18px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.quiz-option {
  margin-top: 10px;
  padding: 10px 12px;
  border-radius: 8px;
  background: #f1f5f9;
  color: #344252;
  font-size: 14px;
}

.quiz-option.selected {
  background: #e8f5f7;
  color: var(--brand-dark);
  font-weight: 700;
}

.section {
  padding: 56px 0;
}

.section.white {
  background: #fff;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.section-intro {
  max-width: 760px;
  color: var(--muted);
}

.grid {
  display: grid;
  gap: 18px;
}

.feature-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-top: 26px;
}

.card {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.feature-icon {
  display: grid;
  width: 40px;
  height: 40px;
  margin-bottom: 14px;
  place-items: center;
  border-radius: 8px;
  background: var(--soft);
  color: var(--brand);
  font-weight: 800;
}

.card p {
  margin-top: 10px;
  color: var(--muted);
  font-size: 15px;
}

.screens {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 26px;
}

.screen-placeholder {
  display: flex;
  min-height: 360px;
  flex-direction: column;
  justify-content: space-between;
  padding: 18px;
  border: 1px dashed #c8d2dc;
  border-radius: 8px;
  background: linear-gradient(180deg, #ffffff 0%, #f2f6f8 100%);
}

.screenshot-card {
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  box-shadow: 0 10px 24px rgba(31, 41, 51, 0.08);
}

.app-screenshot {
  display: block;
  width: 100%;
  border-radius: 8px;
  background: #f3f6f8;
}

.screenshot-caption {
  margin: 12px 4px 4px;
  color: var(--brand-dark);
  font-weight: 700;
  text-align: center;
}

.screen-icon {
  width: 64px;
  height: 64px;
  margin-bottom: 18px;
  border-radius: 15px;
  object-fit: cover;
  box-shadow: 0 8px 20px rgba(31, 41, 51, 0.12);
}

.placeholder-bars span {
  display: block;
  height: 12px;
  margin-bottom: 12px;
  border-radius: 999px;
  background: #dbe3ea;
}

.placeholder-bars span:nth-child(2) {
  width: 74%;
}

.placeholder-bars span:nth-child(3) {
  width: 58%;
}

.placeholder-label {
  color: var(--brand-dark);
  font-weight: 700;
}

.page-hero {
  padding: 52px 0 34px;
  background: #fff;
  border-bottom: 1px solid var(--line);
}

.page-hero h1 {
  font-size: clamp(30px, 4vw, 42px);
}

.page-hero p {
  max-width: 760px;
  margin-top: 12px;
  color: var(--muted);
}

.content {
  width: min(920px, calc(100% - 32px));
  margin: 0 auto;
  padding: 42px 0 64px;
}

.content-card {
  padding: 30px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

.content h2 {
  margin-top: 34px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
  font-size: 23px;
}

.content h2:first-child {
  margin-top: 0;
  padding-top: 0;
  border-top: 0;
}

.content h3 {
  margin-top: 22px;
  margin-bottom: 8px;
}

.content p,
.content li {
  color: #394756;
}

.meta {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px 18px;
  margin: 0 0 26px;
  padding: 16px;
  border-radius: 8px;
  background: #f5f8fa;
  color: #435263;
}

.info-list {
  display: grid;
  gap: 10px;
  margin-top: 18px;
}

.info-row {
  display: grid;
  grid-template-columns: 130px minmax(0, 1fr);
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.info-row strong {
  color: #172331;
}

table {
  width: 100%;
  margin: 18px 0 6px;
  border-collapse: collapse;
  overflow-wrap: anywhere;
}

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

th {
  background: #f3f7f8;
  color: #172331;
}

.notice {
  margin: 20px 0;
  padding: 16px 18px;
  border-left: 4px solid var(--brand);
  border-radius: 8px;
  background: #f1f8f9;
  color: #344252;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: #172331;
  color: #dbe3ea;
}

.footer-inner {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 30px 0;
}

.footer-company {
  margin-bottom: 8px;
  color: #fff;
  font-weight: 700;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin: 10px 0;
}

.footer-links a {
  color: #dbe3ea;
}

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

.footer-note {
  margin: 8px 0 0;
  color: #aeb9c5;
  font-size: 14px;
}

@media (max-width: 900px) {
  .hero-inner {
    grid-template-columns: 1fr;
    gap: 34px;
    padding: 52px 0 42px;
  }

  .phone-preview {
    margin: 0;
  }

  .feature-grid,
  .screens {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 680px) {
  .nav {
    width: min(100% - 24px, 1120px);
    min-height: 58px;
  }

  .nav-toggle {
    display: inline-grid;
    place-items: center;
  }

  .nav-links {
    position: absolute;
    top: 58px;
    right: 12px;
    left: 12px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 10px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: #fff;
    box-shadow: var(--shadow);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    padding: 12px;
  }

  .container,
  .content,
  .footer-inner {
    width: min(100% - 24px, 1120px);
  }

  .hero-subtitle {
    font-size: 19px;
  }

  .feature-grid,
  .screens {
    grid-template-columns: 1fr;
  }

  .screen-placeholder {
    min-height: 260px;
  }

  .content-card {
    padding: 22px 16px;
  }

  .meta,
  .info-row {
    grid-template-columns: 1fr;
  }

  table {
    display: block;
    overflow-x: auto;
    white-space: nowrap;
  }
}