/* ============================================================
   Aircon Price — 디자인 시스템
   팔레트: 딥블루 #1E6FD9 · 아이스민트 #3EC9C0 · 차콜 #1F2A37
   스케일: 8pt 그리드 · 라운드/섀도/보더 토큰
   ============================================================ */
:root {
  /* color */
  --c-primary: #1E6FD9;
  --c-primary-600: #155FBF;
  --c-primary-700: #104E9E;
  --c-primary-50: #EAF3FF;
  --c-accent: #3EC9C0;
  --c-accent-600: #17A79E;
  --c-accent-50: #E8F8F6;
  --c-ink: #1F2A37;
  --c-body: #4B5563;
  --c-muted: #6B7280;
  --c-surface: #F4F7FB;
  --c-surface-2: #F8FAFD;
  --c-border: #E2E8F0;
  --c-border-strong: #CBD5E1;
  --c-amber: #E08A2B;
  --c-amber-50: #FBF3EA;
  --c-white: #FFFFFF;
  /* radius */
  --r-lg: 20px;
  --r-md: 14px;
  --r-sm: 10px;
  /* shadow */
  --sh-sm: 0 1px 2px rgba(31,42,55,.06), 0 1px 3px rgba(31,42,55,.08);
  --sh-md: 0 4px 12px rgba(31,42,55,.08), 0 2px 4px rgba(31,42,55,.05);
  --sh-lg: 0 16px 40px rgba(31,42,55,.12);
  /* space (8pt) */
  --s-1: 8px; --s-2: 16px; --s-3: 24px; --s-4: 32px; --s-5: 40px;
  --s-6: 48px; --s-7: 56px; --s-8: 64px; --s-9: 80px; --s-10: 96px; --s-11: 112px; --s-12: 128px;
  /* font */
  --font-sans: 'Pretendard Variable', Pretendard, -apple-system, BlinkMacSystemFont, system-ui, Roboto, 'Helvetica Neue', 'Segoe UI', 'Apple SD Gothic Neo', 'Noto Sans KR', sans-serif;
  --font-serif: 'Noto Serif KR', 'Pretendard Variable', serif;
  --fs-hero: clamp(2.2rem, 5vw, 3.75rem);
  --fs-h2: clamp(1.5rem, 3vw, 2.1rem);
  --fs-body: 17px;
  --lh-body: 1.78;
  --wrap: 1120px;
  --wrap-narrow: 780px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--c-ink);
  background: var(--c-white);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--c-primary-700); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--c-primary); }
.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--s-3); }

:focus-visible { outline: 3px solid var(--c-accent); outline-offset: 3px; border-radius: 4px; }
.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--c-primary); color: #fff; padding: 12px 20px; border-radius: 0 0 12px 0;
}
.skip-link:focus { left: 0; color: #fff; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--c-border);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; min-height: 72px; gap: var(--s-3); }
.brand { display: inline-flex; align-items: center; gap: 12px; text-decoration: none; color: var(--c-ink); }
.brand-mark { width: 44px; height: 44px; flex: 0 0 auto; }
.brand-mark svg { width: 100%; height: 100%; display: block; }
.brand-text { display: flex; flex-direction: column; line-height: 1.25; }
.brand-name { font-weight: 700; font-size: 17px; letter-spacing: -0.02em; }
.brand-sub { font-size: 12px; color: var(--c-muted); letter-spacing: -0.01em; }
.site-nav .nav-list { display: flex; gap: 4px; list-style: none; margin: 0; padding: 0; }
.site-nav .nav-list a {
  display: inline-block; padding: 10px 14px; border-radius: 999px;
  font-size: 15px; font-weight: 600; color: var(--c-ink); text-decoration: none;
  transition: background .2s ease, color .2s ease;
}
.site-nav .nav-list a:hover { background: var(--c-primary-50); color: var(--c-primary-700); }
.nav-toggle { display: none; background: none; border: 1px solid var(--c-border); border-radius: 10px; width: 44px; height: 44px; cursor: pointer; padding: 10px; }
.nav-toggle span { display: block; height: 2px; background: var(--c-ink); margin: 4px 0; border-radius: 2px; transition: transform .25s ease, opacity .25s ease; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }
.mobile-menu { background: var(--c-white); border-bottom: 1px solid var(--c-border); }
.mobile-nav { list-style: none; margin: 0; padding: 8px var(--s-3) var(--s-3); display: grid; gap: 4px; }
.mobile-nav a { display: block; padding: 13px 10px; border-radius: 10px; font-weight: 600; text-decoration: none; color: var(--c-ink); }
.mobile-nav a:hover { background: var(--c-primary-50); color: var(--c-primary-700); }

/* ---------- 페이지 헤드 ---------- */
.page-head { padding: var(--s-9) 0 var(--s-5); max-width: var(--wrap); }
.page-title { font-family: var(--font-serif); font-size: clamp(1.9rem, 4vw, 2.8rem); line-height: 1.35; margin: 0 0 var(--s-2); letter-spacing: -0.02em; word-break: keep-all; }
.page-sub { color: var(--c-body); font-size: 17px; max-width: 640px; line-height: 1.7; }

/* ---------- Post grid ---------- */
.post-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--s-4); padding: var(--s-4) 0 var(--s-9); }
.post-card { border-radius: var(--r-md); border: 1px solid var(--c-border); background: var(--c-white); overflow: hidden; transition: transform .25s ease, box-shadow .25s ease; }
.post-card:hover { transform: translateY(-4px); box-shadow: var(--sh-md); }
.post-card-link { display: block; text-decoration: none; color: inherit; height: 100%; }
.post-card-thumb { display: block; aspect-ratio: 16/9; overflow: hidden; background: var(--c-surface); }
.post-card-thumb img { width: 100%; height: 100%; object-fit: cover; transition: transform .3s ease; }
.post-card:hover .post-card-thumb img { transform: scale(1.04); }
.post-card-body { display: block; padding: var(--s-3); }
.post-card-cat { display: inline-block; font-size: 12.5px; font-weight: 700; color: var(--c-primary-700); background: var(--c-primary-50); padding: 4px 10px; border-radius: 999px; margin-bottom: 10px; }
.post-card-title { display: block; font-size: 18px; font-weight: 700; line-height: 1.45; letter-spacing: -0.015em; word-break: keep-all; color: var(--c-ink); }
.post-card-date { display: block; margin-top: 10px; font-size: 13px; color: var(--c-muted); }
.pagination { display: flex; gap: 8px; justify-content: center; padding-bottom: var(--s-9); }
.pagination a, .pagination span { padding: 10px 16px; border: 1px solid var(--c-border); border-radius: 10px; text-decoration: none; color: var(--c-ink); }
.empty { padding: var(--s-9) 0; color: var(--c-muted); }

/* ---------- Single ---------- */
.single-article { padding-bottom: var(--s-9); }
.single-head { padding: var(--s-8) 0 var(--s-4); background: linear-gradient(180deg, var(--c-primary-50) 0%, rgba(255,255,255,0) 100%); }
.breadcrumb { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; font-size: 14px; color: var(--c-muted); margin-bottom: var(--s-3); }
.breadcrumb a { color: var(--c-primary-700); text-decoration: none; }
.single-title { font-family: var(--font-serif); font-size: clamp(1.7rem, 3.6vw, 2.6rem); line-height: 1.4; margin: 0 0 var(--s-2); letter-spacing: -0.02em; word-break: keep-all; max-width: 820px; }
.single-meta { font-size: 14px; color: var(--c-muted); display: flex; gap: 8px; align-items: center; margin: 0 0 var(--s-4); }
.single-hero { margin: var(--s-4) 0 0; }
.single-hero img { border-radius: var(--r-lg); box-shadow: var(--sh-md); width: 100%; max-width: 900px; }
.single-layout { max-width: var(--wrap-narrow); padding-top: var(--s-5); }
.single-content { font-size: var(--fs-body); line-height: var(--lh-body); color: var(--c-body); }
.single-content > * + * { margin-top: 1.35em; }
.single-content h2 {
  font-family: var(--font-serif);
  font-size: var(--fs-h2);
  line-height: 1.45;
  color: var(--c-ink);
  margin: 2.2em 0 .8em;
  letter-spacing: -0.015em;
  word-break: keep-all;
  scroll-margin-top: 96px;
}
.single-content h2::before { content: ''; display: inline-block; width: 10px; height: 24px; border-radius: 4px; background: linear-gradient(180deg, var(--c-primary), var(--c-accent)); margin-right: 12px; vertical-align: -4px; }
.single-content h3 { font-family: var(--font-serif); font-size: 1.25rem; color: var(--c-ink); margin: 1.6em 0 .6em; word-break: keep-all; }
.single-content p { margin: 0 0 1.15em; word-break: keep-all; }
.single-content ul, .single-content ol { margin: 0 0 1.3em; padding-left: 1.4em; }
.single-content li { margin-bottom: .45em; }
.single-content strong { color: var(--c-ink); }
.single-content a { font-weight: 600; }

.post-lead { font-size: 18px; color: var(--c-ink); line-height: 1.8; }
.key-summary {
  background: var(--c-surface-2);
  border: 1px solid var(--c-border);
  border-left: 4px solid var(--c-primary);
  border-radius: var(--r-md);
  padding: var(--s-3) var(--s-4);
  margin: var(--s-4) 0;
}
.key-summary > strong { display: block; font-size: 16px; margin-bottom: 10px; color: var(--c-primary-700); }
.key-summary ul { margin: 0; padding-left: 1.2em; }

/* tables */
.content-table { margin: var(--s-5) 0; }
.content-table figcaption { font-size: 13.5px; color: var(--c-muted); margin: 0 0 10px; }
.content-table table { width: 100%; border-collapse: collapse; font-size: 15px; line-height: 1.6; border-radius: var(--r-md); overflow: hidden; box-shadow: var(--sh-sm); }
.content-table th { background: var(--c-primary); color: #fff; text-align: left; padding: 12px 16px; font-weight: 600; font-size: 14.5px; white-space: nowrap; }
.content-table td { padding: 12px 16px; border-bottom: 1px solid var(--c-border); background: var(--c-white); color: var(--c-body); vertical-align: top; word-break: keep-all; }
.content-table tbody tr:nth-child(even) td { background: var(--c-surface-2); }
.content-table tbody tr:last-child td { border-bottom: none; }

/* inline chart */
.inline-chart { margin: var(--s-5) 0; padding: var(--s-4); background: var(--c-surface-2); border: 1px solid var(--c-border); border-radius: var(--r-md); display: grid; gap: 14px; }
.chart-row { display: grid; grid-template-columns: 150px 1fr 150px; gap: 12px; align-items: center; font-size: 14px; }
.chart-label { color: var(--c-ink); font-weight: 600; }
.chart-track { height: 10px; border-radius: 999px; background: var(--c-border); overflow: hidden; }
.chart-bar { display: block; height: 100%; border-radius: 999px; background: linear-gradient(90deg, var(--c-primary), var(--c-accent)); }
.chart-note { color: var(--c-muted); font-size: 13px; }

/* callout / info */
.callout {
  margin: var(--s-5) 0; padding: var(--s-3) var(--s-4);
  background: var(--c-accent-50); border-left: 4px solid var(--c-accent-600);
  border-radius: 0 var(--r-md) var(--r-md) 0;
}
.callout strong { display: block; color: var(--c-ink); margin-bottom: 6px; }
.callout p { margin: 0; color: var(--c-body); }
.info-note { margin: var(--s-4) 0; padding: var(--s-3) var(--s-4); background: var(--c-primary-50); border-left: 4px solid var(--c-primary); border-radius: 0 var(--r-md) var(--r-md) 0; }
.info-note strong { display: block; color: var(--c-primary-700); margin-bottom: 6px; }
.info-note p { margin: 0; color: var(--c-body); }

/* figure */
.content-figure { margin: var(--s-5) 0; }
.content-figure img { border-radius: var(--r-md); box-shadow: var(--sh-sm); width: 100%; }
.content-figure figcaption { font-size: 13.5px; color: var(--c-muted); margin-top: 8px; text-align: center; }

/* faq */
.faq { margin: var(--s-5) 0; border-top: 1px solid var(--c-border); }
.faq h3 { cursor: default; }
.faq h3 + p { margin-top: -0.4em; }

/* related links / meta */
.related-links { margin-top: var(--s-5); padding: var(--s-3) var(--s-4); background: var(--c-surface-2); border: 1px solid var(--c-border); border-radius: var(--r-md); font-size: 15px; }
.related-links strong { color: var(--c-ink); }
.post-meta { font-size: 13.5px; color: var(--c-muted); margin-top: var(--s-5); border-top: 1px solid var(--c-border); padding-top: var(--s-3); }

/* TOC */
.toc { margin: var(--s-4) 0 var(--s-5); padding: var(--s-3) var(--s-4); background: var(--c-surface-2); border: 1px solid var(--c-border); border-radius: var(--r-md); }
.toc-title { font-weight: 700; color: var(--c-ink); margin: 0 0 8px; font-size: 15px; }
.toc ol { margin: 0; padding-left: 1.3em; display: grid; gap: 4px; }
.toc a { font-size: 14.5px; color: var(--c-body); text-decoration: none; }
.toc a:hover { color: var(--c-primary-700); }

/* related posts */
.related-posts { max-width: var(--wrap); margin: var(--s-9) auto 0; padding: var(--s-6) var(--s-3); border-top: 1px solid var(--c-border); }
.related-title { font-family: var(--font-serif); font-size: 1.6rem; margin: 0 0 var(--s-4); letter-spacing: -0.02em; }
.related-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--s-4); }
.related-card { display: block; border: 1px solid var(--c-border); border-radius: var(--r-md); overflow: hidden; text-decoration: none; background: var(--c-white); transition: transform .25s ease, box-shadow .25s ease; }
.related-card:hover { transform: translateY(-4px); box-shadow: var(--sh-md); }
.related-thumb { display: block; aspect-ratio: 16/9; background-size: cover; background-position: center; }
.related-body { display: block; padding: var(--s-3); }
.related-cat { display: inline-block; font-size: 12px; font-weight: 700; color: var(--c-primary-700); background: var(--c-primary-50); padding: 3px 9px; border-radius: 999px; margin-bottom: 8px; }
.related-name { display: block; font-size: 16px; font-weight: 700; color: var(--c-ink); line-height: 1.5; word-break: keep-all; }

/* buttons */
.btn { display: inline-block; padding: 14px 26px; background: var(--c-primary); color: #fff; border-radius: 999px; font-weight: 700; text-decoration: none; transition: background .2s ease, transform .2s ease; }
.btn:hover { background: var(--c-primary-600); color: #fff; transform: translateY(-1px); }

/* ---------- Footer ---------- */
.site-footer { background: var(--c-ink); color: #C7D0DA; margin-top: var(--s-9); }
.footer-top { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: var(--s-5); padding: var(--s-9) var(--s-3) var(--s-6); }
.footer-brand-name { font-family: var(--font-serif); color: #fff; font-size: 19px; margin: 0 0 12px; letter-spacing: -0.01em; }
.footer-brand-desc { font-size: 14.5px; line-height: 1.75; margin: 0; max-width: 360px; }
.footer-col-title { color: #fff; font-size: 15px; font-weight: 700; margin: 0 0 14px; }
.footer-col ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 9px; }
.footer-col a { color: #C7D0DA; font-size: 14.5px; text-decoration: none; }
.footer-col a:hover { color: #fff; }
.footer-notices { background: rgba(0,0,0,.22); }
.footer-notices .wrap { padding-top: var(--s-4); padding-bottom: var(--s-4); display: grid; gap: 10px; }
.footer-notice-legal { font-size: 12.5px; line-height: 1.7; color: #AAB4C0; margin: 0; }
.footer-notice-ai { font-size: 12.5px; color: #AAB4C0; margin: 0; }
.footer-notice-info { font-size: 12.5px; color: #AAB4C0; margin: 0; line-height: 1.7; }
.footer-copy { font-size: 12.5px; color: #8B95A1; margin: 8px 0 0; }

/* ---------- 반응형 ---------- */
@media (max-width: 1024px) {
  .footer-top { grid-template-columns: 1fr 1fr; }
  .post-grid, .related-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .site-nav { display: none; }
  .nav-toggle { display: block; }
  .single-head { padding-top: var(--s-6); }
  .single-layout { padding-top: var(--s-4); }
  .chart-row { grid-template-columns: 1fr; gap: 6px; }
  .chart-note { font-size: 12.5px; }
}
@media (max-width: 560px) {
  .post-grid, .related-grid { grid-template-columns: 1fr; }
  .footer-top { grid-template-columns: 1fr; gap: var(--s-4); }
  .brand-sub { display: none; }
  .content-table { overflow-x: auto; }
  .content-table table { min-width: 560px; }
  .content-table { -webkit-overflow-scrolling: touch; }
}

/* ---------- 모션 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}
.reveal { opacity: 0; transform: translateY(18px); transition: opacity .5s ease, transform .5s ease; }
.reveal.is-visible { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { .reveal { opacity: 1; transform: none; } }