/* ============================================
   大空土木工業 — 土木・基礎工事のデモサイト
   配色: 紺(navy) + スチール(steel) + 警告黄(safety yellow)
   ============================================ */

:root {
  --navy: #0F2A44;
  --navy-dark: #081A2E;
  --navy-light: #1E456A;
  --steel: #4A5568;
  --steel-light: #718096;
  --steel-pale: #E2E8F0;
  --yellow: #FFC72C;
  --yellow-dark: #E6A800;
  --bg: #FFFFFF;
  --bg-soft: #F5F7FA;
  --bg-soft2: #ECEEF2;
  --text: #1A202C;
  --text-soft: #4A5568;
  --border: #CBD2DA;
  --shadow-sm: 0 2px 6px rgba(15, 42, 68, 0.06);
  --shadow-md: 0 8px 24px rgba(15, 42, 68, 0.10);
  --font-sans: 'Noto Sans JP', 'Hiragino Kaku Gothic ProN', sans-serif;
  --font-display: 'Oswald', 'Noto Sans JP', sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  color: var(--text);
  background: var(--bg);
  line-height: 1.85;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--navy); text-decoration: none; transition: color .2s; }
a:hover { color: var(--yellow-dark); }

/* === Demo banner === */
.demo-banner {
  background: var(--yellow);
  color: var(--navy-dark);
  text-align: center;
  font-size: 12px;
  font-weight: 700;
  padding: 6px 12px;
  letter-spacing: 0.05em;
}
.demo-banner a { color: var(--navy-dark); text-decoration: underline; }

/* === Header === */
.site-header {
  background: var(--navy);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 3px solid var(--yellow);
}
.header-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}
.brand {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}
.brand-mark {
  font-family: var(--font-display);
  font-size: 11px;
  letter-spacing: 0.25em;
  color: var(--yellow);
  font-weight: 700;
}
.brand-name {
  font-size: 18px;
  font-weight: 900;
  letter-spacing: 0.05em;
  color: #fff;
}
.brand-name span { color: var(--yellow); }
.nav {
  display: flex;
  gap: 24px;
  font-size: 14px;
  font-weight: 700;
}
.nav a { color: rgba(255,255,255,0.85); }
.nav a:hover, .nav a.active { color: var(--yellow); }
.nav .cta {
  background: var(--yellow);
  color: var(--navy-dark);
  padding: 8px 18px;
  border-radius: 2px;
  letter-spacing: 0.05em;
}
.nav .cta:hover { background: #fff; color: var(--navy-dark); }

/* === Hero === */
.hero {
  background:
    linear-gradient(135deg, rgba(8, 26, 46, 0.86), rgba(15, 42, 68, 0.78)),
    url("https://images.unsplash.com/photo-1503387762-592deb58ef4e?w=1600&q=80&auto=format&fit=crop") center/cover no-repeat,
    var(--navy);
  color: #fff;
  padding: 100px 24px;
  text-align: left;
  position: relative;
  overflow: hidden;
}
.hero::after {
  content: "";
  position: absolute;
  right: -120px;
  bottom: -120px;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(255,199,44,0.18), transparent 65%);
  pointer-events: none;
}
.hero-inner {
  max-width: 1120px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}
.hero-eyebrow {
  display: inline-block;
  background: var(--yellow);
  color: var(--navy-dark);
  font-size: 12px;
  font-weight: 700;
  padding: 4px 14px;
  margin-bottom: 24px;
  letter-spacing: 0.15em;
}
.hero h1 {
  font-size: clamp(32px, 5.5vw, 56px);
  font-weight: 900;
  line-height: 1.35;
  margin-bottom: 24px;
  letter-spacing: 0.02em;
}
.hero h1 em {
  color: var(--yellow);
  font-style: normal;
}
.hero p.lead {
  font-size: clamp(15px, 2vw, 17px);
  max-width: 640px;
  margin-bottom: 36px;
  opacity: 0.9;
}
.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

/* === Buttons === */
.btn {
  display: inline-block;
  padding: 14px 32px;
  border-radius: 2px;
  font-weight: 700;
  letter-spacing: 0.1em;
  font-size: 14px;
  transition: transform .2s, background .2s, color .2s;
  cursor: pointer;
  border: 0;
}
.btn-primary { background: var(--yellow); color: var(--navy-dark); }
.btn-primary:hover { background: #fff; color: var(--navy-dark); transform: translateY(-2px); }
.btn-outline { background: transparent; color: #fff; border: 1px solid rgba(255,255,255,0.5); }
.btn-outline:hover { background: rgba(255,255,255,0.1); border-color: #fff; }
.btn-solid { background: var(--navy); color: #fff; }
.btn-solid:hover { background: var(--navy-dark); }

/* === Section base === */
.section { padding: 90px 24px; }
.section-alt { background: var(--bg-soft); }
.section-dark { background: var(--navy); color: #fff; }
.container { max-width: 1120px; margin: 0 auto; }
.section-head { margin-bottom: 56px; }
.section-head .tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.3em;
  color: var(--yellow-dark);
  margin-bottom: 14px;
}
.section-head .tag::before {
  content: "";
  width: 24px;
  height: 2px;
  background: var(--yellow);
}
.section-head h2 {
  font-size: clamp(26px, 4vw, 38px);
  font-weight: 900;
  line-height: 1.45;
  letter-spacing: 0.04em;
}
.section-head p.sub {
  margin-top: 16px;
  color: var(--text-soft);
  max-width: 640px;
}
.section-dark .section-head .tag { color: var(--yellow); }
.section-dark .section-head .tag::before { background: var(--yellow); }
.section-dark .section-head p.sub { color: rgba(255,255,255,0.75); }

/* === Strength cards === */
.strength-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}
.strength {
  background: #fff;
  border: 1px solid var(--border);
  border-top: 4px solid var(--yellow);
  padding: 32px 28px;
  position: relative;
}
.strength-num {
  font-family: var(--font-display);
  font-size: 40px;
  font-weight: 700;
  color: var(--yellow-dark);
  line-height: 1;
  margin-bottom: 12px;
}
.strength h3 {
  font-size: 19px;
  font-weight: 900;
  margin-bottom: 12px;
  letter-spacing: 0.04em;
}
.strength p {
  font-size: 14px;
  color: var(--text-soft);
}

/* === Services grid === */
.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
}
.service {
  background: var(--navy);
  color: #fff;
  padding: 36px 28px;
  position: relative;
  border-left: 4px solid var(--yellow);
  transition: transform .25s;
}
.service:hover { transform: translateY(-4px); }
.service-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255,199,44,0.15);
  margin-bottom: 18px;
}
.service-icon svg { width: 24px; height: 24px; color: var(--yellow); }
.service h3 {
  font-size: 18px;
  font-weight: 900;
  margin-bottom: 10px;
  letter-spacing: 0.04em;
}
.service p {
  font-size: 13px;
  color: rgba(255,255,255,0.78);
  line-height: 1.85;
}

/* === Works gallery === */
.works-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}
.work {
  background: #fff;
  border: 1px solid var(--border);
  overflow: hidden;
  transition: transform .25s, box-shadow .25s;
}
.work:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.work-image {
  aspect-ratio: 4/3;
  background-color: var(--navy);
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255,255,255,0); /* hide placeholder label when image loads */
  font-family: var(--font-display);
  font-size: 13px;
  letter-spacing: 0.3em;
  position: relative;
}
.work-image::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(8,26,46,0) 60%, rgba(8,26,46,0.45) 100%);
}
.work-tag {
  position: absolute;
  top: 12px;
  left: 12px;
  background: var(--yellow);
  color: var(--navy-dark);
  padding: 3px 10px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  z-index: 1;
}
.work-body { padding: 20px; }
.work-body h3 {
  font-size: 16px;
  font-weight: 900;
  margin-bottom: 8px;
}
.work-meta {
  display: flex;
  gap: 12px;
  font-size: 12px;
  color: var(--text-soft);
  flex-wrap: wrap;
}
.work-meta span::before { content: "・"; }
.work-meta span:first-child::before { content: ""; }

/* === Numbers / KPI === */
.kpi-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 24px;
  margin-top: 24px;
}
.kpi {
  text-align: center;
  padding: 24px 16px;
  border: 1px solid rgba(255,255,255,0.18);
}
.kpi-num {
  font-family: var(--font-display);
  font-size: 48px;
  font-weight: 700;
  color: var(--yellow);
  line-height: 1;
  margin-bottom: 8px;
}
.kpi-num small { font-size: 18px; margin-left: 4px; opacity: 0.85; }
.kpi-label {
  font-size: 13px;
  letter-spacing: 0.1em;
  color: rgba(255,255,255,0.85);
}

/* === CTA strip === */
.cta-strip {
  background: var(--yellow);
  color: var(--navy-dark);
  padding: 56px 24px;
  text-align: center;
}
.cta-strip h2 {
  font-size: clamp(22px, 3.5vw, 32px);
  font-weight: 900;
  margin-bottom: 16px;
  letter-spacing: 0.05em;
}
.cta-strip p { margin-bottom: 28px; font-size: 15px; }
.cta-strip .btn-solid { background: var(--navy-dark); color: var(--yellow); }
.cta-strip .btn-solid:hover { background: var(--navy); }

/* === Table === */
.spec-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
}
.spec-table th, .spec-table td {
  text-align: left;
  padding: 18px 16px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.spec-table th {
  width: 200px;
  color: var(--text-soft);
  font-weight: 700;
  background: var(--bg-soft);
  letter-spacing: 0.05em;
}

/* === Form === */
.form-wrap { max-width: 720px; margin: 0 auto; }
.field { margin-bottom: 24px; }
.field label {
  display: block;
  font-weight: 700;
  margin-bottom: 8px;
  font-size: 14px;
}
.field label .req {
  background: var(--yellow);
  color: var(--navy-dark);
  font-size: 10px;
  padding: 2px 6px;
  margin-left: 8px;
  letter-spacing: 0.1em;
}
.field input, .field textarea, .field select {
  width: 100%;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: 2px;
  font-family: inherit;
  font-size: 15px;
  background: #fff;
  transition: border-color .2s;
}
.field input:focus, .field textarea:focus, .field select:focus {
  outline: 0;
  border-color: var(--navy);
}
.field textarea { resize: vertical; min-height: 140px; }
.form-submit { text-align: center; margin-top: 32px; }

/* === Footer === */
.site-footer {
  background: var(--navy-dark);
  color: rgba(255,255,255,0.65);
  padding: 56px 24px 24px;
}
.footer-inner {
  max-width: 1120px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}
.footer-brand .brand-name { color: #fff; }
.footer-brand p { font-size: 13px; margin-top: 12px; }
.footer-col h4 {
  font-size: 13px;
  font-weight: 700;
  color: var(--yellow);
  letter-spacing: 0.15em;
  margin-bottom: 14px;
}
.footer-col ul { list-style: none; font-size: 13px; line-height: 2.2; }
.footer-col a { color: rgba(255,255,255,0.65); }
.footer-col a:hover { color: var(--yellow); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 16px;
  font-size: 11px;
  text-align: center;
  opacity: 0.5;
  letter-spacing: 0.05em;
}

/* === Page header (non-top pages) === */
.page-hero {
  background: var(--navy);
  color: #fff;
  padding: 80px 24px 60px;
  border-bottom: 3px solid var(--yellow);
}
.page-hero .container { display: flex; align-items: baseline; gap: 24px; flex-wrap: wrap; }
.page-hero h1 {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 900;
  letter-spacing: 0.05em;
}
.page-hero .en {
  font-family: var(--font-display);
  color: var(--yellow);
  font-size: 14px;
  letter-spacing: 0.3em;
}

/* === Mobile === */
@media (max-width: 768px) {
  .nav { display: none; }
  .hero { padding: 70px 20px; }
  .section { padding: 60px 20px; }
  .footer-inner { grid-template-columns: 1fr; gap: 28px; }
  .spec-table th { width: 110px; font-size: 13px; }
}