/* ==========================================================================
   앱인코리아 디자인 시스템 — appinkorea_ui_ux_design_spec.md 기반
   ========================================================================== */

:root {
  color-scheme: light dark;

  /* Primary Brand Colors */
  --primary-600: #6366f1;
  --primary-700: #4f46e5;
  --primary-soft: rgba(99, 102, 241, 0.1);

  --accent-green: #10b981;
  --accent-amber: #f59e0b;

  /* 카테고리별 포인트 컬러 (indigo=앱 리뷰, amber=앱테크, green=혜택/딜) */
  --cat-indigo: #4f46e5;
  --cat-indigo-soft: rgba(79, 70, 229, 0.1);
  --cat-amber: #d97706;
  --cat-amber-soft: rgba(217, 119, 6, 0.12);
  --cat-green: #059669;
  --cat-green-soft: rgba(5, 150, 105, 0.1);

  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --border-color: #e2e8f0;

  --dark-bg-main: #0f172a;
  --dark-bg-card: #1e293b;
  --dark-text-main: #f8fafc;
  --dark-text-muted: #94a3b8;
  --dark-border-color: #334155;

  --surface: light-dark(var(--bg-main), var(--dark-bg-main));
  --surface-card: light-dark(var(--bg-card), var(--dark-bg-card));
  --text-primary: light-dark(var(--text-main), var(--dark-text-main));
  --text-secondary: light-dark(var(--text-muted), var(--dark-text-muted));
  --border: light-dark(var(--border-color), var(--dark-border-color));

  --font-family: 'Pretendard Variable', 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --line-height-body: 1.75;

  --space-1: 4px; --space-2: 8px; --space-3: 12px; --space-4: 16px;
  --space-5: 24px; --space-6: 32px; --space-7: 48px; --space-8: 64px;

  --ease-standard: cubic-bezier(0.4, 0, 0.2, 1);
  --duration-fast: 150ms;
  --duration-base: 250ms;
}

/* 구버전 브라우저(light-dark() 미지원) 폴백: data-theme 속성으로 수동 오버라이드 */
:root[data-theme="dark"] {
  --surface: var(--dark-bg-main);
  --surface-card: var(--dark-bg-card);
  --text-primary: var(--dark-text-main);
  --text-secondary: var(--dark-text-muted);
  --border: var(--dark-border-color);
  --cat-indigo: #a5b4fc;
  --cat-indigo-soft: rgba(165, 180, 252, 0.14);
  --cat-amber: #fbbf24;
  --cat-amber-soft: rgba(251, 191, 36, 0.14);
  --cat-green: #34d399;
  --cat-green-soft: rgba(52, 211, 153, 0.14);
}
:root[data-theme="light"] {
  --surface: var(--bg-main);
  --surface-card: var(--bg-card);
  --text-primary: var(--text-main);
  --text-secondary: var(--text-muted);
  --border: var(--border-color);
}

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

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-family);
  background: var(--surface);
  color: var(--text-primary);
  line-height: var(--line-height-body);
  font-size: clamp(16px, 0.5vw + 15px, 17px);
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-5);
}

a { color: var(--primary-600); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3, h4 { color: var(--text-primary); line-height: 1.3; font-weight: 800; }
h1 { font-size: clamp(28px, 3vw + 20px, 40px); margin: var(--space-5) 0 var(--space-3); }
h2 { font-size: clamp(22px, 1.5vw + 18px, 28px); font-weight: 700; margin: var(--space-7) 0 var(--space-4); padding-bottom: var(--space-2); border-bottom: 1px solid var(--border); }
h3 { font-size: clamp(18px, 1vw + 16px, 22px); font-weight: 600; margin: var(--space-6) 0 var(--space-3); padding-left: var(--space-3); border-left: 4px solid var(--primary-600); }
p { margin: 0 0 var(--space-4); }
ul, ol { padding-left: var(--space-6); }
img { max-width: 100%; height: auto; display: block; border-radius: 8px; }

.skip-link {
  position: absolute; left: -9999px; top: 0;
  background: var(--primary-600); color: #fff; padding: var(--space-3) var(--space-4);
  z-index: 1000;
}
.skip-link:focus { left: var(--space-4); top: var(--space-4); }

:focus-visible { outline: 2px solid var(--primary-600); outline-offset: 2px; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: color-mix(in srgb, var(--surface-card) 80%, transparent);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px) saturate(160%);
  -webkit-backdrop-filter: blur(12px) saturate(160%);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}
.site-logo {
  font-size: 20px; font-weight: 800;
  background: linear-gradient(135deg, var(--primary-700), var(--primary-600) 55%, #818cf8);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.site-nav ul { list-style: none; display: flex; gap: var(--space-5); margin: 0; padding: 0; }
.site-nav a { color: var(--text-primary); font-weight: 600; font-size: 15px; }
.site-nav a:hover { color: var(--primary-600); text-decoration: none; }
.header-actions { display: flex; align-items: center; gap: var(--space-2); }

.btn-icon {
  min-width: 40px; min-height: 40px;
  border: 1px solid var(--border); background: var(--surface-card);
  border-radius: 8px; cursor: pointer; font-size: 16px; color: var(--text-primary);
}
.icon-moon { display: none; }
:root[data-theme="dark"] .icon-sun { display: none; }
:root[data-theme="dark"] .icon-moon { display: inline; }

#mobile-menu-toggle { display: none; }
.mobile-nav ul { list-style: none; margin: 0; padding: var(--space-4) var(--space-5); display: flex; flex-direction: column; gap: var(--space-3); }
.mobile-nav {
  border-bottom: 1px solid var(--border);
  background: var(--surface-card);
  overflow: hidden;
  max-height: 0;
  opacity: 0;
  transition: max-height var(--duration-base) var(--ease-standard), opacity var(--duration-base) var(--ease-standard);
}
.mobile-nav:not([hidden]) { max-height: 320px; opacity: 1; }
.mobile-nav a { color: var(--text-primary); font-weight: 600; }

@media (max-width: 768px) {
  .site-nav { display: none; }
  #mobile-menu-toggle { display: inline-block; }
}

/* ---------- Hero / Sections ---------- */
.hero {
  position: relative;
  overflow: hidden;
  padding: var(--space-8) 0 var(--space-7);
  text-align: center;
  isolation: isolate;
}
.hero-decor {
  position: absolute; inset: -20% -10% auto -10%; height: 420px;
  background:
    radial-gradient(closest-side, rgba(99, 102, 241, 0.22), transparent),
    radial-gradient(closest-side, rgba(16, 185, 129, 0.14), transparent 70%);
  background-position: 15% 20%, 85% 40%;
  background-repeat: no-repeat;
  background-size: 55% 100%, 45% 90%;
  filter: blur(40px);
  z-index: -1;
  pointer-events: none;
}
:root[data-theme="dark"] .hero-decor { opacity: 0.6; }
.hero-inner { position: relative; }
.hero-eyebrow {
  display: inline-block; font-size: 13px; font-weight: 700;
  color: var(--primary-700); background: var(--primary-soft);
  padding: 6px 16px; border-radius: 999px; margin-bottom: var(--space-4);
}
:root[data-theme="dark"] .hero-eyebrow { color: #c7d2fe; }
.hero h1, .hero-title { margin-top: 0; }
.text-gradient {
  background: linear-gradient(135deg, var(--primary-700), var(--primary-600) 45%, var(--accent-green));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero p { color: var(--text-secondary); font-size: 18px; max-width: 640px; margin: 0 auto; }

.section-title { display: flex; align-items: baseline; gap: var(--space-3); }
.section-title a.view-all { font-size: 14px; font-weight: 600; }

/* ---------- Post Card Grid ---------- */
.post-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-5);
  margin: var(--space-5) 0 var(--space-7);
}
.post-card {
  background: var(--surface-card);
  border: 1px solid var(--border);
  border-top: 3px solid var(--primary-600);
  border-radius: 12px;
  overflow: hidden;
  transition: transform var(--duration-base) var(--ease-standard), box-shadow var(--duration-base) var(--ease-standard), border-color var(--duration-base) var(--ease-standard);
}
.post-card:hover { transform: translateY(-4px); box-shadow: 0 12px 28px rgba(15, 23, 42, 0.1); }
.post-card-indigo { border-top-color: var(--cat-indigo); }
.post-card-amber { border-top-color: var(--cat-amber); }
.post-card-green { border-top-color: var(--cat-green); }
.post-card-link { display: block; padding: var(--space-5); color: inherit; }
.post-card-link:hover { text-decoration: none; }
.post-card-title { font-size: 18px; margin: var(--space-3) 0 var(--space-2); }
.post-card-excerpt { color: var(--text-secondary); font-size: 14px; margin-bottom: var(--space-3); }
.post-card-meta { font-size: 13px; color: var(--text-secondary); }

.badge {
  display: inline-block; font-size: 12px; font-weight: 700;
  padding: 4px 10px; border-radius: 999px;
}
.badge-category, .badge-indigo { background: var(--cat-indigo-soft); color: var(--cat-indigo); }
.badge-amber { background: var(--cat-amber-soft); color: var(--cat-amber); }
.badge-green { background: var(--cat-green-soft); color: var(--cat-green); }

/* ---------- AI 요약 박스 (GEO) ---------- */
.ai-summary-box {
  background: var(--primary-soft);
  border: 1px solid var(--primary-600);
  border-radius: 12px;
  padding: var(--space-5);
  margin: var(--space-5) 0 var(--space-7);
}
.ai-summary-label { font-weight: 800; color: var(--primary-700); display: block; margin-bottom: var(--space-2); }
:root[data-theme="dark"] .ai-summary-label { color: #a5b4fc; }
.ai-summary-list { margin: 0; padding-left: var(--space-5); }
.ai-summary-list li { margin-bottom: var(--space-2); }
.ai-summary-updated { margin: var(--space-3) 0 0; font-size: 13px; color: var(--text-secondary); }

/* ---------- 목차(TOC) ---------- */
.toc-box {
  background: var(--surface-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: var(--space-5);
  margin: var(--space-5) 0 var(--space-7);
  max-width: 760px;
}
.toc-label { font-weight: 800; display: block; margin-bottom: var(--space-3); }
.toc-list { margin: 0; padding-left: 0; list-style: none; }
.toc-list li { margin-bottom: var(--space-2); padding-left: var(--space-4); position: relative; }
.toc-list li::before { content: '›'; position: absolute; left: 0; color: var(--primary-600); font-weight: 800; }
.toc-list a { color: var(--text-primary); font-weight: 600; }
.toc-list a:hover { color: var(--primary-600); }

/* ---------- 스크롤 진행 표시줄 ---------- */
.post-progress {
  position: fixed; top: 0; left: 0; height: 3px; width: 0%;
  background: linear-gradient(90deg, var(--primary-600), var(--accent-green));
  z-index: 200;
  transition: width 80ms linear;
}

/* ---------- 맨 위로 버튼 ---------- */
.back-to-top {
  display: flex; align-items: center; justify-content: center;
  position: fixed; right: var(--space-5); bottom: var(--space-5);
  width: 44px; height: 44px; border-radius: 50%;
  background: var(--primary-600); color: #fff; border: none;
  font-size: 18px; cursor: pointer;
  box-shadow: 0 8px 20px rgba(79, 70, 229, 0.35);
  opacity: 0; visibility: hidden; transform: translateY(12px);
  transition: opacity var(--duration-base) var(--ease-standard), transform var(--duration-base) var(--ease-standard), background var(--duration-fast);
  z-index: 90;
}
.back-to-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { background: var(--primary-700); }

/* ---------- 광고 슬롯 (CLS 방지용 자리 확보) ---------- */
.ad-slot {
  display: flex; align-items: center; justify-content: center;
  min-height: 100px;
  background: var(--surface-card);
  border: 1px dashed var(--border);
  border-radius: 8px;
  color: var(--text-secondary);
  font-size: 12px;
  margin: var(--space-6) 0;
}

/* ---------- Post Detail ---------- */
.post-detail { padding: var(--space-6) 0 var(--space-8); }
.post-breadcrumb { font-size: 13px; color: var(--text-secondary); margin-bottom: var(--space-3); }
.post-meta { color: var(--text-secondary); font-size: 14px; margin-bottom: var(--space-5); display: flex; gap: var(--space-4); flex-wrap: wrap; }
.post-body { max-width: 760px; }
.post-body h2:first-child { margin-top: var(--space-4); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block; padding: 10px 20px; border-radius: 8px;
  font-weight: 700; font-size: 15px; cursor: pointer; border: none;
}
.btn-primary { background: var(--primary-600); color: #fff; }
.btn-primary:hover { background: var(--primary-700); text-decoration: none; }
.btn-secondary { background: transparent; color: var(--primary-600); border: 1.5px solid var(--primary-600); }
.btn-secondary:hover { text-decoration: none; background: var(--primary-soft); }

/* ---------- Channel CTA ---------- */
.channel-cta { background: var(--surface-card); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); padding: var(--space-7) 0; }
.channel-cta-inner { display: flex; align-items: center; justify-content: space-between; gap: var(--space-5); flex-wrap: wrap; }
.channel-cta h2 { margin: 0 0 var(--space-2); border: none; padding: 0; }
.channel-cta p { margin: 0; color: var(--text-secondary); }
.channel-cta-buttons { display: flex; gap: var(--space-3); flex-shrink: 0; }

/* ---------- Footer ---------- */
.site-footer { background: var(--surface); padding: var(--space-7) 0; font-size: 13px; color: var(--text-secondary); }
.footer-inner { display: flex; flex-direction: column; gap: var(--space-3); }
.footer-brand strong { color: var(--text-primary); font-size: 16px; }
.footer-links { display: flex; gap: var(--space-4); flex-wrap: wrap; }
.footer-links a { color: var(--text-secondary); font-weight: 600; }
.footer-disclosure { max-width: 800px; line-height: 1.6; }

/* ---------- Toast ---------- */
.toast-notification {
  position: fixed; bottom: 24px; left: 50%; transform: translate(-50%, 20px);
  background: var(--text-primary); color: var(--surface);
  padding: 12px 20px; border-radius: 8px; font-size: 14px;
  opacity: 0; transition: opacity var(--duration-base), transform var(--duration-base);
  z-index: 1000;
}
.toast-notification.show { opacity: 1; transform: translate(-50%, 0); }

/* ---------- Category page ---------- */
.category-header {
  padding: var(--space-6) var(--space-5) var(--space-5);
  margin: var(--space-4) 0;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: linear-gradient(135deg, var(--cat-indigo-soft), transparent 70%);
}
.category-header .badge { margin-bottom: var(--space-3); }
.category-header h1 { margin-top: var(--space-2); }
.category-header-amber { background: linear-gradient(135deg, var(--cat-amber-soft), transparent 70%); }
.category-header-green { background: linear-gradient(135deg, var(--cat-green-soft), transparent 70%); }
.category-count { font-size: 13px; color: var(--text-secondary); font-weight: 600; margin: 0; }