/* ABSTRA — Global Styles (Light Surface · Master Brand)
 * SSOT: ABSTRAkr/ABSTRA repo / library/rules/11-abstra-brand-policy.md §3-1
 * 톤 차별화: Torchline = 다크 + 메탈릭 / ABSTRA = 라이트 + Master Brand
 */

:root {
  /* Master Brand 토큰 (11-abstra-brand-policy §3-1) */
  --abstra-ring: #BE852B;
  --abstra-flame-outer: #FF6B00;
  --abstra-flame-mid: #FA5500;
  --abstra-flame-core: #E12014;
  --abstra-accent: #C18616;
  --abstra-ink: #131313;

  /* 라이트 surface */
  --abstra-surface: #FAFAF7;
  --abstra-surface-alt: #F0EDE5;
  --abstra-surface-elev: #FFFFFF;
  --abstra-text: #131313;
  --abstra-text-muted: #5C5C5C;
  --abstra-divider: rgba(0, 0, 0, 0.08);
  --abstra-flame-accent: var(--abstra-flame-outer);

  /* 레이아웃 */
  --measure: 68ch;
  --max-width: 720px;
  --max-width-wide: 1080px;
  --spacing-section: clamp(3rem, 2rem + 5vw, 8rem);
  --spacing-block: clamp(1.5rem, 1rem + 2vw, 3rem);

  /* 타이포 스케일 */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: clamp(1.8rem, 1.2rem + 2vw, 2.25rem);
  --text-4xl: clamp(2.25rem, 1.4rem + 3vw, 3rem);
  --text-display: clamp(2.5rem, 1.4rem + 4vw, 4rem);

  /* 모션 */
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
  --duration-fast: 150ms;
  --duration-normal: 300ms;
}

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

html { scroll-behavior: smooth; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: 'Pretendard', 'Apple SD Gothic Neo', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--abstra-surface);
  color: var(--abstra-text);
  line-height: 1.7;
  font-size: var(--text-base);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
  text-decoration: underline;
  text-decoration-color: var(--abstra-divider);
  text-underline-offset: 0.2em;
  transition: text-decoration-color var(--duration-fast) var(--ease-out-expo);
}
a:hover { text-decoration-color: var(--abstra-flame-accent); }
a:focus-visible {
  outline: 2px solid var(--abstra-flame-accent);
  outline-offset: 3px;
  border-radius: 2px;
}

img, svg { max-width: 100%; height: auto; display: block; }

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--abstra-flame-accent);
  color: var(--abstra-surface-elev);
  padding: 0.5rem 1rem;
  text-decoration: none;
  z-index: 100;
}
.skip-link:focus { top: 0; }

/* Header */
.site-header {
  border-bottom: 1px solid var(--abstra-divider);
  padding: 1.25rem clamp(1rem, 3vw, 2rem);
  background: var(--abstra-surface);
}
.site-header nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: var(--max-width-wide);
  margin: 0 auto;
}
.brand-lockup {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
  text-decoration: none;
}
.brand-lockup .symbol { width: 32px; height: 32px; }
.brand-lockup .wordmark {
  height: 22px;
  width: auto;
  display: block;
}
.nav-menu {
  display: flex;
  gap: clamp(1rem, 2vw, 2rem);
  list-style: none;
  align-items: center;
}
.nav-menu a {
  text-decoration: none;
  color: var(--abstra-text-muted);
  font-size: var(--text-sm);
  transition: color var(--duration-fast) var(--ease-out-expo);
}
.nav-menu a:hover { color: var(--abstra-text); }
.nav-cta {
  color: var(--abstra-text) !important;
  border: 1px solid var(--abstra-flame-accent);
  padding: 0.4rem 0.9rem;
  border-radius: 999px;
}
.nav-cta:hover {
  background: var(--abstra-flame-accent);
  color: var(--abstra-surface-elev) !important;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--abstra-divider);
  padding: 2rem clamp(1rem, 3vw, 2rem);
  text-align: center;
  color: var(--abstra-text-muted);
  font-size: var(--text-sm);
  background: var(--abstra-surface);
}
.site-footer p + p { margin-top: 0.4rem; }

/* Prose */
.prose {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 clamp(1rem, 3vw, 2rem);
}
.prose h1, .prose h2, .prose h3 {
  line-height: 1.3;
  color: var(--abstra-text);
  font-weight: 700;
  letter-spacing: -0.01em;
}
.prose h1 { font-size: var(--text-4xl); margin-bottom: var(--spacing-block); }
.prose h2 { font-size: var(--text-3xl); margin-top: var(--spacing-section); margin-bottom: 1rem; }
.prose h3 { font-size: var(--text-2xl); margin-top: 2rem; margin-bottom: 0.75rem; }
.prose p + p { margin-top: 1rem; }
.prose > * + * { margin-top: 0.5rem; }
.prose blockquote {
  border-left: 3px solid var(--abstra-flame-accent);
  padding: 0.25rem 0 0.25rem 1.25rem;
  margin: 1.5rem 0;
  color: var(--abstra-text-muted);
  font-style: italic;
}
.prose blockquote p { margin-top: 0; }
.prose ul, .prose ol { padding-left: 1.5rem; margin: 1rem 0; }
.prose li + li { margin-top: 0.25rem; }
.prose hr {
  border: none;
  border-top: 1px solid var(--abstra-divider);
  margin: 2rem 0;
}
.prose strong { color: var(--abstra-text); font-weight: 700; }
.prose em { color: var(--abstra-text-muted); }
.prose code {
  background: var(--abstra-surface-alt);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  font-size: 0.92em;
}

/* Hero */
.hero {
  padding: clamp(4rem, 4rem + 5vw, 9rem) clamp(1rem, 3vw, 2rem) var(--spacing-section);
  max-width: var(--max-width-wide);
  margin: 0 auto;
}
.hero h1 {
  font-size: var(--text-display);
  line-height: 1.1;
  letter-spacing: -0.02em;
  font-weight: 700;
  max-width: 18ch;
}
.hero p.tagline {
  margin-top: 1.5rem;
  font-size: var(--text-xl);
  color: var(--abstra-text-muted);
  max-width: 38ch;
  line-height: 1.55;
}
.hero .cta-group {
  margin-top: 2.5rem;
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* Button */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  font-weight: 600;
  font-size: var(--text-base);
  text-decoration: none;
  transition: background var(--duration-fast) var(--ease-out-expo),
              transform var(--duration-fast) var(--ease-out-expo);
  border: 1px solid transparent;
  cursor: pointer;
}
.btn-primary {
  background: var(--abstra-flame-accent);
  color: var(--abstra-surface-elev);
}
.btn-primary:hover { background: var(--abstra-flame-mid); }
.btn-ghost {
  background: transparent;
  color: var(--abstra-text);
  border-color: var(--abstra-divider);
}
.btn-ghost:hover { border-color: var(--abstra-text-muted); }

/* Article list */
.article-list {
  list-style: none;
  padding: 0;
  display: grid;
  gap: var(--spacing-block);
  max-width: var(--max-width);
  margin: 0 auto;
}
.article-card {
  border-top: 1px solid var(--abstra-divider);
  padding-top: var(--spacing-block);
}
.article-card:first-child { border-top: none; padding-top: 0; }
.article-card a { text-decoration: none; display: block; }
.article-card a:hover h3 { color: var(--abstra-flame-accent); }
.article-card h3 {
  font-size: var(--text-2xl);
  margin-bottom: 0.5rem;
  transition: color var(--duration-fast) var(--ease-out-expo);
}
.article-card time {
  font-size: var(--text-sm);
  color: var(--abstra-text-muted);
  display: block;
  margin-bottom: 0.75rem;
}
.article-card .description {
  color: var(--abstra-text-muted);
  line-height: 1.6;
}