/* ==========================================================================
   CurrencyRate - Apple Human Interface Guidelines Inspired Web Stylesheet
   Clean, accessible, responsive design with native system fonts & Dark Mode
   ========================================================================== */

:root {
  --font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display", "Helvetica Neue", Arial, sans-serif;
  --bg-primary: #F2F2F7;
  --bg-secondary: #FFFFFF;
  --bg-card: #FFFFFF;
  --text-primary: #1C1C1E;
  --text-secondary: #8E8E93;
  --text-tertiary: #C7C7CC;
  --accent: #0A84FF; /* Apple System Blue */
  --accent-subtle: rgba(10, 132, 255, 0.12);
  --accent-hover: #0066CC;
  --border-color: #E5E5EA;
  --border-subtle: rgba(0, 0, 0, 0.06);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.06);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #000000;
    --bg-secondary: #1C1C1E;
    --bg-card: #1C1C1E;
    --text-primary: #FFFFFF;
    --text-secondary: #8E8E93;
    --text-tertiary: #48484A;
    --accent: #0A84FF;
    --accent-subtle: rgba(10, 132, 255, 0.2);
    --accent-hover: #409CFF;
    --border-color: #2C2C2E;
    --border-subtle: rgba(255, 255, 255, 0.08);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.4);
  }
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  padding: 0;
  margin: 0;
}

.container {
  max-width: 760px;
  margin: 0 auto;
  padding: 40px 20px 80px 20px;
}

/* Header & Navigation */
header.site-header {
  margin-bottom: 32px;
  text-align: center;
}

.brand-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: var(--accent-subtle);
  color: var(--accent);
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 16px;
  text-decoration: none;
}

.site-title {
  font-size: 32px;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.site-subtitle {
  font-size: 16px;
  color: var(--text-secondary);
}

.nav-tabs {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-top: 24px;
  flex-wrap: wrap;
}

.nav-tab {
  padding: 8px 16px;
  background: var(--bg-card);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 500;
  text-decoration: none;
  transition: all 0.15s ease;
}

.nav-tab:hover {
  color: var(--text-primary);
  border-color: var(--text-secondary);
}

.nav-tab.active {
  background: var(--text-primary);
  color: var(--bg-primary);
  border-color: var(--text-primary);
}

/* Main Content Card */
.content-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 36px 32px;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-md);
  margin-bottom: 32px;
}

@media (max-width: 600px) {
  .content-card {
    padding: 24px 20px;
    border-radius: var(--radius-md);
  }
}

.meta-box {
  background: var(--bg-primary);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  margin-bottom: 28px;
  font-size: 13px;
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
}

.meta-box p {
  margin: 4px 0;
}

.meta-box strong {
  color: var(--text-primary);
}

/* Typography */
h2 {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
  margin-top: 32px;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-subtle);
}

h3 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin-top: 20px;
  margin-bottom: 8px;
}

p, li {
  font-size: 15px;
  color: var(--text-primary);
  line-height: 1.65;
  margin-bottom: 14px;
}

ul, ol {
  padding-left: 24px;
  margin-bottom: 16px;
}

li {
  margin-bottom: 6px;
}

strong {
  font-weight: 600;
}

code {
  font-family: SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 13px;
  background: var(--bg-primary);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--accent);
}

a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
}

a:hover {
  text-decoration: underline;
}

.callout {
  padding: 16px 20px;
  border-radius: var(--radius-md);
  background: var(--accent-subtle);
  border-left: 4px solid var(--accent);
  margin: 20px 0;
  font-size: 14px;
}

.callout strong {
  color: var(--accent);
}

/* Feature Grid */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
  margin: 24px 0;
}

.feature-item {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  padding: 20px;
  border-radius: var(--radius-md);
}

.feature-icon {
  font-size: 24px;
  margin-bottom: 8px;
}

.feature-item h3 {
  margin-top: 0;
  margin-bottom: 6px;
}

.feature-item p {
  font-size: 13.5px;
  color: var(--text-secondary);
  margin-bottom: 0;
}

/* FAQ Item */
.faq-item {
  border-bottom: 1px solid var(--border-subtle);
  padding: 18px 0;
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-question {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.faq-answer {
  font-size: 14.5px;
  color: var(--text-secondary);
  margin-bottom: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  background: var(--accent);
  color: #FFFFFF !important;
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.15s ease;
  margin-top: 12px;
}

.btn:hover {
  background: var(--accent-hover);
  text-decoration: none;
}

footer.site-footer {
  text-align: center;
  font-size: 13px;
  color: var(--text-secondary);
  margin-top: 40px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.footer-links a {
  color: var(--text-secondary);
}

.footer-links a:hover {
  color: var(--text-primary);
}