/* Rentong Forging - Industrial Technology Site (Blue-Red Brand Color System) */
:root {
  --ink: #0D1B2A;
  --steel: #1B3A5C;
  --steel-light: #2C5282;
  --accent: #2B6CB0;
  --accent-dark: #1A365D;
  --accent-light: #63B3ED;  --bg: #FFFFFF;
  --bg-alt: #F7FAFC;
  --text: #1A1B1C;
  --text-secondary: #5A6B7B;
  --border: #E2E8F0;
}
* { margin:0; padding:0; box-sizing:border-box; }
html { scroll-behavior:smooth; }
body { font-family:'Roboto','PingFang SC','Segoe UI',Arial,sans-serif; color:var(--text); line-height:1.6; background:var(--bg); }
img { max-width:100%; }
.container { max-width:1180px; margin:0 auto; padding:0 28px; }

/* Navbar */
.navbar { background:rgba(13,27,42,0.97); backdrop-filter:blur(8px); padding:16px 0; position:sticky; top:0; z-index:100; box-shadow:0 2px 20px rgba(0,0,0,0.2); }
.navbar .container { display:flex; align-items:center; justify-content:space-between; flex-wrap:wrap; gap:10px; }
.logo { display:flex; align-items:center; gap:12px; color:#fff; text-decoration:none; font-weight:700; font-size:1.2rem; letter-spacing:0.5px; }
.logo img { height:38px; width:auto; }
.logo span { color:var(--accent-light); }
.nav-links { display:flex; list-style:none; gap:26px; flex-wrap:wrap; }
.nav-links a { color:#B8C8D8; text-decoration:none; font-size:0.92rem; font-weight:500; transition:color .2s; position:relative; }
.nav-links a:hover, .nav-links a.active { color:#fff; }
.nav-links a.active::after { content:''; position:absolute; bottom:-6px; left:0; right:0; height:2px; background:var(--accent); border-radius:2px; }

/* Hero with factory background */
.hero { position:relative; color:#fff; padding:120px 0 130px; overflow:hidden; background:linear-gradient(135deg,#0D1B2A 0%,#1B3A5C 50%,#2C5282 100%); }
.hero-bg { position:absolute; inset:0; background-size:cover; background-position:center; opacity:0.35; }
.hero-overlay { position:absolute; inset:0; background:linear-gradient(135deg,rgba(13,27,42,0.85) 0%,rgba(27,58,92,0.7) 60%,rgba(44,82,130,0.6) 100%); }
.hero-content { position:relative; z-index:2; }
.hero-badge { display:inline-block; background:rgba(43,108,176,0.2); color:var(--accent-light); border:1px solid rgba(43,108,176,0.5); padding:8px 18px; border-radius:999px; font-size:0.82rem; letter-spacing:1.5px; margin-bottom:24px; }
.hero h1 { font-size:3rem; line-height:1.15; margin-bottom:22px; font-weight:700; }
.hero h1 span { color:var(--accent-light); }
.hero p { max-width:660px; color:#C0D0E0; font-size:1.1rem; margin-bottom:36px; line-height:1.7; }
.btn { display:inline-flex; align-items:center; gap:8px; padding:14px 32px; border-radius:8px; font-weight:600; font-size:0.95rem; text-decoration:none; transition:all .25s; border:none; cursor:pointer; }
.btn-primary { background:var(--accent); color:#fff; box-shadow:0 4px 20px rgba(43,108,176,0.35); }
.btn-primary:hover { background:var(--accent-light); transform:translateY(-2px); box-shadow:0 6px 24px rgba(43,108,176,0.45); }
.btn-outline { border:1.5px solid rgba(255,255,255,0.5); color:#fff; background:transparent; }
.btn-outline:hover { border-color:var(--accent-light); color:var(--accent-light); background:rgba(255,255,255,0.05); }

/* Sections */
.section { padding:80px 0; }
.section-alt { background:var(--bg-alt); }
.section-label { color:var(--accent); font-size:0.82rem; font-weight:700; letter-spacing:2.5px; margin-bottom:12px; text-transform:uppercase; }
.section-title { font-size:2.1rem; margin-bottom:16px; color:var(--ink); font-weight:700; line-height:1.25; }
.section-desc { color:var(--text-secondary); max-width:660px; margin-bottom:40px; font-size:1.02rem; line-height:1.7; }
.section-header { margin-bottom:40px; }

/* Cards */
.cards-grid { display:grid; grid-template-columns:repeat(auto-fit,minmax(250px,1fr)); gap:24px; }
.card { background:#fff; border:1px solid var(--border); border-radius:14px; padding:30px 26px; transition:transform .25s, box-shadow .25s, border-color .25s; }
.card:hover { transform:translateY(-4px); box-shadow:0 16px 40px rgba(13,27,42,0.1); border-color:var(--accent-light); }
.card-icon { margin-bottom:18px; color:var(--accent); }
.card h3 { font-size:1.1rem; margin-bottom:12px; color:var(--ink); font-weight:600; }
.card p { font-size:0.92rem; color:var(--text-secondary); line-height:1.65; }

/* Feature section */
.feature-section { display:grid; grid-template-columns:1.15fr 0.85fr; gap:56px; align-items:center; }
.feature-section.reverse { grid-template-columns:0.85fr 1.15fr; }
.feature-content h2 { font-size:2rem; margin-bottom:18px; color:var(--ink); font-weight:700; line-height:1.25; }
.feature-content p { color:var(--text-secondary); margin-bottom:16px; line-height:1.7; }
.feature-list { list-style:none; display:grid; gap:12px; margin:20px 0; }
.feature-list li { position:relative; padding-left:28px; color:#2C3E50; font-size:0.96rem; line-height:1.5; }
.feature-list li::before { content:''; position:absolute; left:0; top:9px; width:12px; height:12px; border-radius:50%; background:var(--accent); box-shadow:0 0 0 4px rgba(43,108,176,0.15); }
.feature-visual { background:linear-gradient(135deg,var(--ink),var(--steel)); border-radius:16px; padding:0; overflow:hidden; min-height:320px; display:flex; flex-direction:column; align-items:center; justify-content:center; gap:14px; box-shadow:0 20px 50px rgba(13,27,42,0.2); position:relative; }
.feature-visual.has-image { padding:0; display:block; height:320px; }
.feature-visual img { width:100%; height:100%; object-fit:cover; display:block; }
.feature-visual h3 { color:var(--accent-light); font-size:1.3rem; font-weight:600; }
.feature-visual p { color:#A0B8D0; font-size:0.92rem; padding:0 20px; text-align:center; }

/* Stats */
.stats-grid { display:grid; grid-template-columns:repeat(auto-fit,minmax(200px,1fr)); gap:24px; }
.stat-card { background:#fff; border:1px solid var(--border); border-radius:14px; padding:32px 22px; text-align:center; transition:transform .25s, box-shadow .25s; }
.stat-card:hover { transform:translateY(-3px); box-shadow:0 12px 30px rgba(13,27,42,0.08); }
.stat-number { font-size:2.4rem; font-weight:700; color:var(--accent); line-height:1.1; }
.stat-label { color:var(--text-secondary); font-size:0.88rem; margin-top:10px; line-height:1.4; }

/* Photo block (factory photos) */
.photo-block { border-radius:14px; overflow:hidden; box-shadow:0 12px 36px rgba(13,27,42,0.15); position:relative; }
.photo-block img { width:100%; height:100%; object-fit:cover; display:block; }
.photo-block .photo-caption { position:absolute; bottom:0; left:0; right:0; background:linear-gradient(transparent,rgba(13,27,42,0.85)); color:#fff; padding:40px 24px 20px; font-size:0.9rem; }

/* Timeline */
.timeline { max-width:780px; margin:0 auto; }
.timeline-item { position:relative; padding:0 0 32px 32px; border-left:2px solid var(--border); }
.timeline-item:last-child { border-left-color:transparent; }
.timeline-item::before { content:''; position:absolute; left:-8px; top:4px; width:14px; height:14px; border-radius:50%; background:var(--accent); box-shadow:0 0 0 5px rgba(43,108,176,0.15); }
.timeline-year { color:var(--accent); font-size:0.82rem; font-weight:700; letter-spacing:1.5px; margin-bottom:6px; }
.timeline-title { font-weight:600; font-size:1.08rem; color:var(--ink); margin-bottom:8px; }
.timeline-desc { color:var(--text-secondary); font-size:0.94rem; line-height:1.65; }

/* Page header */
.page-header { background:linear-gradient(135deg,#0D1B2A 0%,#1B3A5C 60%,#2C5282 100%); color:#fff; padding:72px 0 80px; position:relative; overflow:hidden; }
.page-header::after { content:''; position:absolute; top:-60px; right:-60px; width:300px; height:300px; border-radius:50%; background:radial-gradient(circle,rgba(99,179,237,0.15),transparent 70%); }
.page-header h1 { font-size:2.4rem; margin-bottom:14px; font-weight:700; position:relative; z-index:1; }
.page-header h1 span { color:var(--accent-light); }
.page-header p { color:#C0D0E0; max-width:660px; font-size:1.05rem; position:relative; z-index:1; }
.breadcrumb { font-size:0.82rem; color:#7A90A8; margin-bottom:18px; position:relative; z-index:1; }
.breadcrumb a { color:#B8C8D8; text-decoration:none; }
.breadcrumb span { margin:0 8px; }

/* CTA */
.cta-section { background:linear-gradient(135deg,#0D1B2A,#1B3A5C); color:#fff; text-align:center; padding:80px 0; position:relative; overflow:hidden; }
.cta-section::before { content:''; position:absolute; top:-100px; left:50%; transform:translateX(-50%); width:600px; height:300px; border-radius:50%; background:radial-gradient(ellipse,rgba(99,179,237,0.15),transparent 70%); }
.cta-section h2 { font-size:2.1rem; margin-bottom:16px; font-weight:700; position:relative; z-index:1; }
.cta-section p { color:#C0D0E0; max-width:620px; margin:0 auto 34px; font-size:1.05rem; position:relative; z-index:1; }

/* Footer */
.footer { background:var(--ink); color:#8FA0B5; padding:60px 0 0; }
.footer-grid { display:grid; grid-template-columns:2fr 1fr 1fr 1fr; gap:36px; padding-bottom:44px; }
.footer h3 { color:#fff; font-size:1.15rem; margin-bottom:14px; display:flex; align-items:center; gap:10px; }
.footer h3 img { height:32px; width:auto; }
.footer h4 { color:#fff; font-size:0.92rem; margin-bottom:16px; font-weight:600; }
.footer ul { list-style:none; display:grid; gap:10px; }
.footer ul a { color:#8FA0B5; text-decoration:none; font-size:0.9rem; transition:color .2s; }
.footer ul a:hover { color:var(--accent-light); }
.footer-bottom { border-top:1px solid rgba(255,255,255,0.08); padding:20px 0; font-size:0.84rem; color:#5A6B7B; display:flex; justify-content:space-between; flex-wrap:wrap; gap:10px; }

/* Back to top */
.back-to-top { position:fixed; bottom:32px; right:32px; width:48px; height:48px; border-radius:50%; background:var(--accent); color:#fff; border:none; font-size:1.3rem; cursor:pointer; box-shadow:0 4px 16px rgba(43,108,176,0.4); opacity:0; visibility:hidden; transform:translateY(10px); transition:all .3s; z-index:999; display:flex; align-items:center; justify-content:center; }
.back-to-top.visible { opacity:1; visibility:visible; transform:translateY(0); }
.back-to-top:hover { background:var(--accent-light); transform:translateY(-3px); box-shadow:0 6px 20px rgba(43,108,176,0.5); }

/* Responsive */
@media (max-width:820px) {
  .feature-section, .feature-section.reverse { grid-template-columns:1fr; gap:32px; }
  .hero h1 { font-size:2.1rem; }
  .hero { padding:80px 0 90px; }
  .section { padding:56px 0; }
  .section-title { font-size:1.7rem; }
  .footer-grid { grid-template-columns:1fr 1fr; gap:28px; }
  .nav-links { gap:14px; }
  .back-to-top { bottom:20px; right:20px; width:42px; height:42px; }
}