@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

* {
  -webkit-font-smoothing: antialiased;
  box-sizing: border-box;
}

html {
  scroll-padding-top: 80px;
}

body {
  margin: 0;
  font-family: 'Inter', 'Source Sans 3', Arial, sans-serif;
  font-weight: 400;
  line-height: 1.6;
  color: #1e293b;
  background: #ffffff;
}

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

/* OS2 Color palette */
:root {
  --os2-blue: #88B0D8;
  --os2-mint: #C0D0D8;
  --os2-beige: #C4B69C;
  --os2-grey: #D0D0D0;
  --os2-surface: #F8F8F8;
  --foreground: #1e293b;
  --muted-foreground: #64748b;
}

/* Fixed header */
header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  height: 64px;
  display: flex;
  align-items: center;
  padding: 0 40px;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--os2-grey);
}

/* Header layout: logo on left, nav on right */
header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 100%;
  padding: 0;
  gap: 24px;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 40px;
  width: 100%;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 16px;
  font-weight: 700;
  color: var(--foreground);
  flex-shrink: 0;
}

.logo img {
  height: 28px;
  width: auto;
}

.logo-text {
  font-weight: 600;
}

nav {
  flex-shrink: 0;
  margin-left: auto;
}

nav ul {
  display: flex;
  gap: 4px;
  list-style: none;
  margin: 0;
  padding: 0;
}

nav a {
  display: block;
  padding: 8px 12px;
  font-size: 13px;
  font-weight: 500;
  color: var(--muted-foreground);
  border-radius: 6px;
  transition: all 0.15s;
}

nav a:hover {
  color: var(--foreground);
  background: var(--os2-surface);
}

/* Main content */
main {
  padding-top: 64px;
}

/* Hero section */
.hero {
  position: relative;
  padding: 80px 24px 96px;
  overflow: hidden;
  background: linear-gradient(180deg, var(--os2-surface) 0%, #ffffff 100%);
}

.hero::before {
  content: '';
  position: absolute;
  top: -128px;
  right: -128px;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: rgba(192, 208, 216, 0.25);
  filter: blur(60px);
}

.hero::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: -80px;
  width: 300px;
  height: 300px;
  border-radius: 50%;
  background: rgba(136, 176, 216, 0.1);
  filter: blur(60px);
}

.hero .container {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1100px;
}

.hero-content {
  flex: 1;
  max-width: 500px;
  text-align: left;
}

.hero-illustration {
  flex: 1;
  display: flex;
  justify-content: center;
  width: 520px;
  flex-shrink: 0;
}

.hero-illustration svg {
  width: 520px;
  height: 260px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  border: 1px solid var(--os2-grey);
  background: var(--os2-surface);
  border-radius: 9999px;
  font-size: 12px;
  font-weight: 500;
  color: var(--muted-foreground);
  margin-bottom: 16px;
}

.hero-badge-dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--os2-mint);
}

.hero h1 {
  font-size: 48px;
  font-weight: 600;
  letter-spacing: -0.03em;
  margin: 0 0 24px;
  color: var(--foreground);
  line-height: 1.15;
}

.hero-subtitle {
  font-size: 18px;
  color: var(--muted-foreground);
  max-width: 640px;
  margin: 0 auto;
  line-height: 1.7;
}

/* Content sections */
.content-section {
  padding: 120px 40px;
}

.content-section h2 {
  font-size: 32px;
  font-weight: 500;
  margin: 120px 0 24px;
  color: var(--foreground);
  letter-spacing: -0.02em;
}

.content-section h2:first-of-type {
  margin-top: 24px;
}

.content-section h3 {
  font-size: 18px;
  font-weight: 600;
  margin: 24px 0 8px;
  color: var(--foreground);
}

.content-section p {
  font-size: 15px;
  color: var(--muted-foreground);
  line-height: 1.7;
  margin: 0 0 16px;
  max-width: 720px;
}

.content-section ul {
  margin: 0;
  padding-left: 20px;
  color: var(--muted-foreground);
}

.content-section li {
  margin-bottom: 8px;
  font-size: 15px;
}

.content-section table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
}

.content-section th {
  text-align: left;
  padding: 12px 16px;
  background: var(--os2-surface);
  font-weight: 600;
  color: var(--foreground);
  border-bottom: 2px solid var(--os2-grey);
}

.content-section td {
  padding: 12px 16px;
  color: var(--muted-foreground);
  border-bottom: 1px solid var(--os2-grey);
  font-size: 14px;
}

.content-section img {
  max-width: 100%;
  height: auto;
  margin: 24px 0;
  border-radius: 8px;
}

/* Cards Grid Layout */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin: 24px 0;
}

/* Card */
.card {
  background: #ffffff;
  border: 1px solid var(--os2-grey);
  border-radius: 12px;
  padding: 24px;
  margin: 16px 0;
  transition: all 0.2s;
}

.card:hover {
  border-color: rgba(136, 176, 216, 0.4);
  box-shadow: 0 4px 16px rgba(136, 176, 216, 0.12);
}

.card-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 8px;
  background: var(--os2-surface);
  color: var(--os2-blue);
  margin-bottom: 16px;
}

.card-icon svg {
  width: 20px;
  height: 20px;
}

.card h3 {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 500;
  color: var(--foreground);
}

/* Footer */
footer {
  border-top: 1px solid var(--os2-grey);
  padding: 48px 0;
  text-align: center;
  background: var(--os2-surface);
}

footer p {
  font-size: 14px;
  color: var(--muted-foreground);
  margin: 0;
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 32px;
  }

  .hero p {
    font-size: 16px;
  }

  .content-section h2 {
    font-size: 28px;
  }

  .cards-grid {
    grid-template-columns: 1fr;
  }

  nav ul {
    gap: 0;
  }

  nav a {
    font-size: 12px;
    padding: 6px 8px;
  }

  .hero-illustration {
    display: none;
  }

  .hero .container {
    text-align: center;
  }

  .hero-content {
    text-align: center;
  }
}

.card-content {
  margin-top: 8px;
  font-size: 14px;
  color: var(--muted-foreground);
  line-height: 1.7;
}

.card-content p {
  margin: 0;
}

.card-content ul {
  margin: 8px 0 0;
  padding-left: 16px;
}

.card-content li {
  font-size: 14px;
  color: var(--muted-foreground);
  margin-bottom: 4px;
}

/* Shortcode: Card Expanded (Accordion) - using div + JS toggle */
.card-expand {
  background: #ffffff;
  border: 1px solid var(--os2-grey);
  border-radius: 12px;
  margin: 16px 0;
  overflow: hidden;
  cursor: pointer;
}

.card-expand-header {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 24px;
}

.card-expand-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 8px;
  background: var(--os2-surface);
  color: var(--os2-blue);
  flex-shrink: 0;
}

.card-expand-icon svg {
  width: 20px;
  height: 20px;
}

.card-expand-title {
  flex: 1;
  font-size: 16px;
  font-weight: 600;
  color: var(--foreground);
}

.card-expand-chevron {
  width: 16px;
  height: 16px;
  position: relative;
  flex-shrink: 0;
  margin-top: 4px;
}

.card-expand-chevron::before {
  content: '';
  position: absolute;
  width: 8px;
  height: 8px;
  border-right: 2px solid var(--muted-foreground);
  border-bottom: 2px solid var(--muted-foreground);
  transform: rotate(-45deg);
  top: 2px;
  left: 2px;
  transition: transform 0.2s;
}

.card-expand.expanded .card-expand-chevron::before {
  transform: rotate(45deg);
  top: 6px;
}

.card-expand-summary {
  font-size: 14px;
  color: var(--muted-foreground);
  line-height: 1.6;
  margin: 0;
  padding: 0 24px 16px 80px;
}

.card-expand-detail {
  display: none;
  padding: 16px 24px 24px;
  padding-left: 80px;
  font-size: 14px;
  color: var(--muted-foreground);
  line-height: 1.7;
}

.card-expand-detail p {
  margin: 0 0 8px;
}

.card-expand-detail p:last-child {
  margin-bottom: 0;
}

.card-expand.expanded .card-expand-detail {
  display: block;
}