/* concrete-drainage-construction — "콘크리트 매스" concept
   palette: primary #4A4E54 (concrete grey), accent #C2410C (rebar rust-orange) */

:root {
  --primary: #4A4E54;
  --accent: #C2410C;
  --bg: #F1F0EC;
  --bg-panel: #FFFFFF;
  --text: #2B2C2E;
  --text-muted: #6B6E73;
  --border: #D8D6D0;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: 'Noto Sans KR', sans-serif;
  font-display: swap;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--accent);
  color: #fff;
  padding: 0.75em 1em;
  z-index: 100;
}
.skip-link:focus { left: 0; }

.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
}

/* ---------- layout skeleton ---------- */

.layout {
  display: block;
}

.side-nav {
  background: var(--primary);
  color: #fff;
  padding: 0.75rem 1rem;
  position: sticky;
  top: 0;
  z-index: 20;
  overflow-x: auto;
  white-space: nowrap;
}

.side-nav-brand {
  display: none;
}

.side-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 0.5rem;
}

.side-nav li { flex: 0 0 auto; }

.side-nav a {
  display: block;
  color: #fff;
  text-decoration: none;
  padding: 0.6rem 0.9rem;
  border: 1px solid rgba(255,255,255,0.25);
  border-radius: 2px;
  font-weight: 500;
  font-size: 0.95rem;
  min-height: 44px;
  display: flex;
  align-items: center;
}

.side-nav a:hover,
.side-nav a:focus {
  background: var(--accent);
  border-color: var(--accent);
}

.main-content {
  padding: 1.25rem 1rem 3rem;
  max-width: 880px;
  margin: 0 auto;
}

/* ---------- hero ---------- */

.hero { padding-top: 0.5rem; }

.hero-img {
  width: 100%;
  height: auto;
  border: 2px solid var(--primary);
}

.hero h1 {
  font-size: 1.7rem;
  font-weight: 900;
  color: var(--primary);
  margin: 1rem 0 0.75rem;
  letter-spacing: -0.01em;
}

.lead {
  font-size: 1.05rem;
  color: var(--text);
}

/* ---------- section rhythm ---------- */

section { padding: 2rem 0; }

h2 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--primary);
  margin: 0 0 1rem;
  padding-left: 0.75rem;
  border-left: 6px solid var(--accent);
}

h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--primary);
  margin: 1.25rem 0 0.5rem;
}

p { margin: 0 0 1rem; }

.divider {
  border: none;
  border-top: 2px solid var(--accent);
  margin: 0;
}

/* ---------- table ---------- */

.table-wrap {
  overflow-x: auto;
  border: 2px solid var(--primary);
}

table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  background: var(--bg-panel);
}

caption { text-align: left; }

th, td {
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
}

thead th {
  background: var(--primary);
  color: #fff;
  font-weight: 700;
}

tbody th[scope="row"] {
  background: #E8E6E0;
  font-weight: 700;
  white-space: nowrap;
}

/* ---------- gallery ---------- */

.gallery-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.gallery-grid figure {
  margin: 0;
  border: 2px solid var(--primary);
  background: var(--bg-panel);
}

.gallery-grid figcaption {
  padding: 0.6rem 0.8rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
}

/* ---------- checklist ---------- */

.check-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.check-list li {
  position: relative;
  padding: 0.6rem 0 0.6rem 1.5rem;
  border-bottom: 1px solid var(--border);
}

.check-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 1.1rem;
  width: 10px;
  height: 10px;
  background: var(--accent);
}

/* ---------- FAQ ---------- */

.faq-item {
  border: 1px solid var(--border);
  border-left: 4px solid var(--primary);
  margin-bottom: 0.75rem;
  background: var(--bg-panel);
}

.faq-item h3 { margin: 0; }

.faq-q {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 1rem;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  cursor: pointer;
  min-height: 44px;
  position: relative;
  padding-right: 2.5rem;
}

.faq-q::after {
  content: "+";
  position: absolute;
  right: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--accent);
  font-size: 1.3rem;
  font-weight: 900;
}

.faq-q[aria-expanded="true"]::after { content: "\2212"; }

.faq-a {
  padding: 0 1rem 1rem;
  margin: 0;
  color: var(--text);
}

.faq-a[hidden] { display: none; }

/* ---------- CTA ---------- */

.cta-block {
  background: var(--primary);
  color: #fff;
  padding: 1.5rem 1.25rem;
  margin: 0 -1rem;
}

.cta-block h2 { color: #fff; border-left-color: var(--accent); }
.cta-block p { color: #EDEDED; }

.cta-buttons {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.75rem 1.25rem;
  border-radius: 2px;
  font-weight: 700;
  text-decoration: none;
  border: 2px solid transparent;
  font-size: 0.95rem;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: #A3350A; }

.btn-outline {
  background: transparent;
  color: #fff;
  border-color: #fff;
}
.btn-outline:hover { background: rgba(255,255,255,0.12); }

/* ---------- mobile bottom CTA bar ---------- */

.mobile-cta-bar {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  display: flex;
  gap: 0.5rem;
  padding: 0.6rem;
  background: var(--primary);
  border-top: 2px solid var(--accent);
  z-index: 30;
}

.mobile-cta-bar .btn { flex: 1; }

.main-content { padding-bottom: 5.5rem; }

/* ---------- footer ---------- */

.site-footer {
  background: #33363B;
  color: #D8D6D0;
  padding: 2rem 1rem 6.5rem;
}

.site-footer nav ul {
  list-style: none;
  margin: 0 0 1.5rem;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1rem;
}

.site-footer a {
  color: #D8D6D0;
  text-decoration: none;
}

.site-footer a:hover { color: var(--accent); }

.site-footer address {
  font-style: normal;
  line-height: 1.8;
  margin-bottom: 1rem;
}

.site-footer small { color: #9A9C9F; }

/* ---------- breakpoints ---------- */

@media (min-width: 480px) {
  .gallery-grid { grid-template-columns: 1fr 1fr; }
}

@media (min-width: 768px) {
  .layout {
    display: flex;
    align-items: flex-start;
  }

  .side-nav {
    width: 220px;
    flex: 0 0 220px;
    height: 100vh;
    position: sticky;
    top: 0;
    overflow-y: auto;
    padding: 1.5rem 1rem;
  }

  .side-nav-brand {
    display: block;
    font-weight: 900;
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--accent);
    color: #fff;
    text-decoration: none;
  }

  .side-nav ul {
    flex-direction: column;
  }

  .main-content {
    flex: 1;
    min-width: 0;
    padding: 2rem 2rem 3rem;
    max-width: none;
  }

  .cta-block { margin: 0 -2rem; }
}

@media (min-width: 1024px) {
  .mobile-cta-bar { display: none; }
  .main-content { padding-bottom: 3rem; }
  .site-footer { padding-bottom: 2rem; }

  .hero h1 { font-size: 2.1rem; }
}

@media (min-width: 1280px) {
  .main-content { max-width: 960px; padding: 2.5rem 2.5rem 3rem; }
}