:root {
  --bg: #f3f7ff;
  --surface: #ffffff;
  --surface-muted: #f7faff;
  --text: #1b2a41;
  --text-muted: #4f6280;
  --primary: #1a73e8;
  --primary-dark: #0e4fb8;
  --accent: #16a085;
  --warn-bg: #fff9ea;
  --warn-border: #f4c95d;
  --radius: 16px;
  --border: #d8e3f5;
  --shadow: 0 8px 30px rgba(26, 115, 232, 0.08);
}

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

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

body {
  font-family: "Segoe UI", Arial, Helvetica, sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 10% -10%, #dbe8ff 0%, transparent 45%),
    radial-gradient(circle at 90% 0%, #e6fff8 0%, transparent 40%),
    var(--bg);
  line-height: 1.6;
}

a {
  color: var(--primary);
  text-underline-offset: 3px;
}

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

.site-shell {
  max-width: 980px;
  margin: 0 auto;
  padding: 20px 16px 40px;
}

.top-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 12px 14px;
}

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

.brand-badge {
  width: 34px;
  height: 34px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--primary), #2b8ef5);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.25);
}

.brand-logo {
  width: 22px;
  height: 22px;
  object-fit: contain;
  display: block;
}

.hero-logo {
  width: 30px;
  height: 30px;
  object-fit: contain;
  display: block;
}

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.nav-link {
  display: inline-block;
  text-decoration: none;
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  padding: 7px 10px;
  border-radius: 10px;
}

.nav-link:hover,
.nav-link.active {
  background: #eaf2ff;
  color: var(--primary-dark);
}

.hero {
  margin-top: 16px;
  background: linear-gradient(135deg, #0f5dd7, #1d7cf2);
  color: #ffffff;
  border-radius: 20px;
  padding: 22px 20px;
  box-shadow: 0 14px 35px rgba(15, 93, 215, 0.25);
}

.hero-row {
  display: flex;
  gap: 14px;
  align-items: flex-start;
}

.hero-icon {
  width: 50px;
  height: 50px;
  border-radius: 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.18);
  flex-shrink: 0;
  border: 1px solid rgba(255, 255, 255, 0.28);
}

.hero h1 {
  margin: 0 0 8px;
  font-size: clamp(24px, 4vw, 34px);
  line-height: 1.2;
}

.hero p {
  margin: 0;
  max-width: 800px;
  color: rgba(255, 255, 255, 0.95);
}

.meta-row {
  margin-top: 12px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip {
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: 999px;
  font-size: 12px;
  padding: 4px 10px;
  color: #ffffff;
}

.section {
  margin-top: 18px;
}

.section h2 {
  margin: 0 0 8px;
  font-size: 24px;
}

.section-intro {
  margin: 0;
  color: var(--text-muted);
}

.grid {
  display: grid;
  gap: 12px;
}

.grid.cards-3 {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.grid.cards-2 {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
  box-shadow: var(--shadow);
}

.card h3 {
  margin: 0 0 8px;
  font-size: 19px;
}

.card p {
  margin: 0 0 12px;
  color: var(--text-muted);
}

.card-icon {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: #eaf2ff;
  color: var(--primary-dark);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 10px;
}

.button {
  appearance: none;
  display: inline-block;
  text-decoration: none;
  background: var(--primary);
  color: #ffffff;
  border: 1px solid var(--primary);
  border-radius: 10px;
  padding: 8px 12px;
  font-weight: 700;
  font-size: 14px;
}

.button:hover {
  background: var(--primary-dark);
  border-color: var(--primary-dark);
  color: #ffffff;
}

.button.ghost {
  background: #ffffff;
  color: var(--primary-dark);
  border-color: var(--border);
}

.button.ghost:hover {
  background: #f0f6ff;
}

.stack {
  display: grid;
  gap: 12px;
}

.content-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  box-shadow: var(--shadow);
}

.content-card h2 {
  margin: 0 0 8px;
  font-size: 22px;
}

.content-card h3 {
  margin: 0 0 8px;
  font-size: 18px;
}

.content-card p {
  margin: 0 0 10px;
}

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

.content-card li + li {
  margin-top: 6px;
}

.toc {
  padding-left: 18px;
  margin: 0;
}

.toc li + li {
  margin-top: 5px;
}

.notice {
  background: #eaf2ff;
  border-left: 4px solid var(--primary);
  border-radius: 10px;
  padding: 10px 12px;
}

.warning {
  background: var(--warn-bg);
  border-left: 4px solid var(--warn-border);
  border-radius: 10px;
  padding: 10px 12px;
}

.contact-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.contact-list li {
  display: grid;
  grid-template-columns: 115px 1fr;
  gap: 8px;
  margin: 0;
  padding: 9px 0;
  border-bottom: 1px dashed #dce6f5;
}

.contact-list li:last-child {
  border-bottom: 0;
}

.label {
  font-weight: 700;
}

.footer {
  margin-top: 18px;
  background: var(--surface-muted);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 12px 14px;
  color: var(--text-muted);
  font-size: 14px;
}

.footer strong {
  color: var(--text);
}

@media (max-width: 700px) {
  .site-shell {
    padding-top: 14px;
  }

  .hero {
    padding: 18px 14px;
  }

  .hero-row {
    gap: 10px;
  }

  .hero-icon {
    width: 42px;
    height: 42px;
    border-radius: 12px;
  }

  .contact-list li {
    grid-template-columns: 1fr;
    gap: 2px;
  }
}