:root {
  --bg: #f4f7fb;
  --panel: #ffffff;
  --panel-strong: #eef3ff;
  --text: #101828;
  --muted: #475467;
  --line: #d0d5dd;
  --primary: #1458f5;
  --primary-deep: #0b3db1;
  --accent: #14b8a6;
  --radius-xl: 22px;
  --radius-lg: 16px;
  --shadow: 0 18px 50px rgba(16, 24, 40, 0.1);
}

* {
  box-sizing: border-box;
}

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

body {
  font-family: "Noto Sans SC", "Avenir Next", "PingFang SC", sans-serif;
  background: radial-gradient(circle at top right, #d9e8ff 0, rgba(217, 232, 255, 0) 45%), var(--bg);
  color: var(--text);
  line-height: 1.65;
}

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

.container {
  width: min(1100px, calc(100% - 48px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  backdrop-filter: blur(10px);
  background: rgba(244, 247, 251, 0.8);
  border-bottom: 1px solid rgba(208, 213, 221, 0.65);
  z-index: 20;
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: "Space Grotesk", "Avenir Next", sans-serif;
  font-weight: 700;
}

.brand-mark {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: #fff url("assets/app_icon.png") center / 128% 128% no-repeat;
  box-shadow: 0 6px 14px rgba(16, 24, 40, 0.18);
  border: 1px solid rgba(16, 24, 40, 0.08);
}

.nav-links {
  display: inline-flex;
  gap: 22px;
  color: var(--muted);
  font-size: 14px;
}

.nav-actions {
  display: inline-flex;
  align-items: center;
  gap: 14px;
}

.lang-toggle {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--text);
  padding: 8px 12px;
  border-radius: 10px;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
}

.lang-toggle:hover {
  border-color: #b9c4d8;
}

.hero {
  padding: 64px 0 30px;
}

.hero-card {
  background: linear-gradient(145deg, #ffffff 0%, #edf4ff 100%);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow);
  padding: 44px;
  border: 1px solid #d6e4ff;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--primary-deep);
  padding: 7px 12px;
  border-radius: 999px;
  background: rgba(20, 88, 245, 0.1);
  margin-bottom: 18px;
}

h1 {
  margin: 0;
  font-family: "Space Grotesk", "Avenir Next", sans-serif;
  font-size: clamp(32px, 5vw, 56px);
  line-height: 1.1;
  letter-spacing: -0.015em;
}

.hero p {
  margin: 16px 0 0;
  max-width: 780px;
  color: var(--muted);
  font-size: clamp(16px, 2vw, 19px);
}

.hero-actions {
  margin-top: 26px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.btn {
  display: inline-block;
  padding: 12px 18px;
  border-radius: 12px;
  font-weight: 700;
  border: 1px solid transparent;
  transition: transform 0.16s ease, box-shadow 0.16s ease;
}

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

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 10px 22px rgba(20, 88, 245, 0.26);
}

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

.section {
  padding: 50px 0;
}

.section-title {
  margin: 0 0 24px;
  font-family: "Space Grotesk", "Avenir Next", sans-serif;
  font-size: clamp(24px, 3vw, 36px);
}

.section-subtitle {
  margin: -8px 0 26px;
  color: var(--muted);
}

.feature {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 24px;
  align-items: center;
  margin-bottom: 24px;
  background: var(--panel);
  border: 1px solid #e2e8f0;
  border-radius: var(--radius-lg);
  padding: 18px;
  box-shadow: 0 8px 30px rgba(16, 24, 40, 0.07);
}

.feature:nth-child(even) {
  grid-template-columns: 1.2fr 1fr;
}

.feature:nth-child(even) .feature-text {
  order: 2;
}

.feature:nth-child(even) .feature-image {
  order: 1;
}

.feature h3 {
  margin: 8px 0 8px;
  font-size: clamp(20px, 2.5vw, 28px);
  font-weight: 400;
  line-height: 1.25;
}

.feature p {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
}

.feature-image img {
  display: block;
  width: 100%;
  border-radius: 14px;
  border: 1px solid #c9d7f5;
  box-shadow: 0 18px 36px rgba(11, 61, 177, 0.16);
}

.site-footer {
  border-top: 1px solid var(--line);
  padding: 24px 0 44px;
  color: var(--muted);
  font-size: 14px;
}

.legal-page {
  padding: 46px 0 70px;
}

.legal-card {
  background: var(--panel);
  border: 1px solid #dde3eb;
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: 0 10px 28px rgba(16, 24, 40, 0.06);
}

.legal-card h1 {
  font-size: clamp(28px, 4vw, 44px);
}

.legal-meta {
  color: var(--muted);
  margin: 10px 0 24px;
  font-size: 14px;
}

.legal-card h2 {
  margin-top: 28px;
  margin-bottom: 10px;
  font-size: 21px;
}

.legal-card p,
.legal-card li {
  color: #344054;
}

.legal-card ul {
  margin: 8px 0 0;
  padding-left: 20px;
}

.guide-page {
  padding: 46px 0 70px;
}

.guide-card {
  background: var(--panel);
  border: 1px solid #dde3eb;
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: 0 10px 28px rgba(16, 24, 40, 0.06);
}

.guide-card h1 {
  font-size: clamp(28px, 4vw, 44px);
}

.guide-intro {
  color: var(--muted);
  font-size: 17px;
  margin: 10px 0 28px;
}

.guide-toc {
  background: var(--panel-strong);
  border: 1px solid #d6e4ff;
  border-radius: 12px;
  padding: 20px 24px;
  margin-bottom: 32px;
}

.guide-toc-title {
  margin: 0 0 12px;
  font-size: 16px;
  font-family: "Space Grotesk", "Avenir Next", sans-serif;
}

.guide-toc ul {
  margin: 0;
  padding-left: 20px;
  list-style: none;
}

.guide-toc > ul {
  padding-left: 0;
}

.guide-toc li {
  margin: 6px 0;
  font-size: 14px;
  line-height: 1.6;
}

.guide-toc li ul {
  margin-top: 4px;
}

.guide-toc a {
  color: var(--primary);
  transition: color 0.15s;
}

.guide-toc a:hover {
  color: var(--primary-deep);
  text-decoration: underline;
}

.guide-card h2 {
  margin-top: 36px;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 2px solid #e2e8f0;
  font-size: 24px;
  font-family: "Space Grotesk", "Avenir Next", sans-serif;
}

.guide-card h3 {
  margin-top: 24px;
  margin-bottom: 10px;
  font-size: 19px;
  font-weight: 600;
}

.guide-card p {
  color: #344054;
  margin: 10px 0;
  line-height: 1.75;
}

.guide-card ul {
  margin: 8px 0 12px;
  padding-left: 22px;
}

.guide-card li {
  color: #344054;
  margin: 6px 0;
  line-height: 1.75;
}

.guide-card code {
  background: rgba(20, 88, 245, 0.07);
  color: var(--primary-deep);
  padding: 2px 6px;
  border-radius: 5px;
  font-size: 0.9em;
  font-family: "SF Mono", "Fira Code", Menlo, monospace;
}

.guide-card strong {
  font-weight: 700;
  color: var(--text);
}

.guide-card blockquote {
  margin: 16px 0;
  padding: 12px 18px;
  border-left: 4px solid var(--primary);
  background: rgba(20, 88, 245, 0.04);
  border-radius: 0 8px 8px 0;
}

.guide-card blockquote p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.guide-img {
  margin: 16px 0;
}

.guide-img img {
  display: block;
  max-width: 100%;
  border-radius: 12px;
  border: 1px solid #c9d7f5;
  box-shadow: 0 12px 28px rgba(11, 61, 177, 0.12);
}

@media (max-width: 1024px) {
  .feature,
  .feature:nth-child(even) {
    grid-template-columns: 1fr;
  }

  .feature:nth-child(even) .feature-text,
  .feature:nth-child(even) .feature-image {
    order: unset;
  }

}

@media (max-width: 640px) {
  .container {
    width: min(1100px, calc(100% - 28px));
  }

  .hero-card {
    padding: 28px 18px;
  }

  .legal-card,
  .guide-card {
    padding: 22px 16px;
  }

  .nav-links {
    gap: 12px;
    font-size: 13px;
  }

  .nav-actions {
    gap: 8px;
  }
}