/* ===== YUNTEE Staircase Website - Design System ===== */
@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@400;600;700&family=Noto+Sans+SC:wght@300;400;500;700&family=Playfair+Display:ital,wght@0,400;0,600;0,700;1,400&family=Inter:wght@300;400;500;600&display=swap');

:root {
  --primary: #1a1a2e;
  --gold: #c9a96e;
  --gold-light: #e8d5b7;
  --cream: #f5f0eb;
  --dark-card: #2d2d3f;
  --dark-overlay: rgba(26, 26, 46, 0.85);
  --text-light: #f5f0eb;
  --text-muted: #a0a0b0;
  --font-zh-title: 'Noto Serif SC', serif;
  --font-en-title: 'Playfair Display', serif;
  --font-body: 'Inter', 'Noto Sans SC', sans-serif;
  --transition: 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --shadow: 0 20px 60px rgba(0,0,0,0.3);
}

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font-body);
  background: var(--primary);
  color: var(--text-light);
  overflow-x: hidden;
  line-height: 1.8;
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--primary); }
::-webkit-scrollbar-thumb { background: var(--gold); border-radius: 4px; }

/* ===== Navigation ===== */
.navbar {
  position: fixed; top: 0; left: 0; width: 100%; z-index: 1000;
  padding: 1.2rem 4%;
  display: flex; justify-content: space-between; align-items: center;
  transition: var(--transition);
  background: transparent;
}
.navbar.scrolled {
  background: rgba(26, 26, 46, 0.95);
  backdrop-filter: blur(20px);
  padding: 0.8rem 4%;
  box-shadow: 0 2px 30px rgba(0,0,0,0.3);
}
.nav-logo {
  display: flex; align-items: center; gap: 0.6rem;
  text-decoration: none; color: var(--text-light);
}
.nav-logo-icon {
  width: 42px; height: 42px;
  border: 2px solid var(--gold);
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-en-title); font-size: 1.2rem; font-weight: 700;
  color: var(--gold);
  transform: rotate(-5deg);
}
.nav-logo-text {
  display: flex; flex-direction: column; line-height: 1.2;
}
.nav-logo-text .zh { font-family: var(--font-zh-title); font-size: 1.1rem; font-weight: 600; }
.nav-logo-text .en { font-family: var(--font-en-title); font-size: 0.7rem; letter-spacing: 3px; color: var(--gold); text-transform: uppercase; }

.nav-links { display: flex; gap: 2rem; list-style: none; align-items: center; }
.nav-links a {
  text-decoration: none; color: var(--text-light); font-size: 0.9rem;
  font-weight: 400; letter-spacing: 0.5px;
  position: relative; padding-bottom: 4px;
  transition: color 0.3s;
}
.nav-links a::after {
  content: ''; position: absolute; bottom: 0; left: 0;
  width: 0; height: 1.5px; background: var(--gold);
  transition: width 0.3s;
}
.nav-links a:hover { color: var(--gold); }
.nav-links a:hover::after { width: 100%; }

.lang-switch {
  background: none; border: 1px solid var(--gold);
  color: var(--gold); padding: 0.35rem 0.8rem;
  font-size: 0.8rem; cursor: pointer;
  letter-spacing: 1px; transition: var(--transition);
  font-family: var(--font-body);
}
.lang-switch:hover { background: var(--gold); color: var(--primary); }

.nav-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; background: none; border: none; padding: 5px; }
.nav-toggle span { width: 24px; height: 2px; background: var(--text-light); transition: 0.3s; }

/* ===== Hero Section ===== */
.hero {
  position: relative; height: 100vh; min-height: 600px;
  display: flex; align-items: center; justify-content: center;
  overflow: hidden;
}
.hero-bg {
  position: absolute; inset: 0;
  background: url('../images/hero.png') center/cover no-repeat;
  transform: scale(1.05);
  transition: transform 8s ease-out;
}
.hero.loaded .hero-bg { transform: scale(1); }
.hero-overlay {
  position: absolute; inset: 0;
  background: linear-gradient(135deg, rgba(26,26,46,0.8) 0%, rgba(26,26,46,0.4) 50%, rgba(26,26,46,0.7) 100%);
}
.hero-content {
  position: relative; text-align: center; z-index: 2;
  max-width: 800px; padding: 0 2rem;
}
.hero-badge {
  display: inline-block;
  font-family: var(--font-en-title); font-size: 0.8rem;
  letter-spacing: 4px; text-transform: uppercase;
  color: var(--gold); border: 1px solid var(--gold);
  padding: 0.5rem 1.5rem; margin-bottom: 2rem;
  opacity: 0; transform: translateY(30px);
  animation: fadeUp 1s 0.5s forwards;
}
.hero-title {
  font-family: var(--font-zh-title); font-size: clamp(2.2rem, 5vw, 3.6rem);
  font-weight: 700; line-height: 1.4; margin-bottom: 1rem;
  opacity: 0; transform: translateY(30px);
  animation: fadeUp 1s 0.8s forwards;
}
.hero-title .gold { color: var(--gold); }
.hero-subtitle {
  font-family: var(--font-en-title); font-style: italic;
  font-size: clamp(1rem, 2vw, 1.3rem);
  color: var(--gold-light); margin-bottom: 2.5rem;
  opacity: 0; transform: translateY(30px);
  animation: fadeUp 1s 1.1s forwards;
}
.hero-cta {
  display: inline-block;
  background: linear-gradient(135deg, var(--gold), #b8944f);
  color: var(--primary); padding: 1rem 2.5rem;
  text-decoration: none; font-weight: 600; font-size: 0.95rem;
  letter-spacing: 1px; transition: var(--transition);
  opacity: 0; transform: translateY(30px);
  animation: fadeUp 1s 1.4s forwards;
  position: relative; overflow: hidden;
}
.hero-cta::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, transparent, rgba(255,255,255,0.2), transparent);
  transform: translateX(-100%); transition: 0.6s;
}
.hero-cta:hover::before { transform: translateX(100%); }
.hero-cta:hover { transform: translateY(-2px); box-shadow: 0 10px 30px rgba(201,169,110,0.4); }

.scroll-indicator {
  position: absolute; bottom: 2rem; left: 50%; transform: translateX(-50%);
  z-index: 2; display: flex; flex-direction: column; align-items: center; gap: 0.5rem;
  opacity: 0; animation: fadeUp 1s 1.8s forwards;
}
.scroll-indicator span { font-size: 0.7rem; letter-spacing: 2px; color: var(--text-muted); }
.scroll-line { width: 1px; height: 40px; background: var(--gold); animation: scrollPulse 2s infinite; }

@keyframes fadeUp { to { opacity: 1; transform: translateY(0); } }
@keyframes scrollPulse { 0%,100% { opacity: 0.3; transform: scaleY(0.5); } 50% { opacity: 1; transform: scaleY(1); } }

/* ===== Section Common ===== */
.section { padding: 7rem 4%; }
.section-header { text-align: center; margin-bottom: 4rem; }
.section-label {
  display: inline-block; font-family: var(--font-en-title);
  font-size: 0.75rem; letter-spacing: 4px; text-transform: uppercase;
  color: var(--gold); margin-bottom: 0.8rem;
}
.section-title {
  font-family: var(--font-zh-title); font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  font-weight: 700; line-height: 1.4; margin-bottom: 1rem;
}
.section-line {
  width: 60px; height: 2px; background: var(--gold);
  margin: 0 auto;
}

/* ===== Scroll Animation ===== */
.reveal { opacity: 0; transform: translateY(40px); transition: all 0.8s cubic-bezier(0.25, 0.46, 0.45, 0.94); }
.reveal.active { opacity: 1; transform: translateY(0); }
.reveal-left { opacity: 0; transform: translateX(-60px); transition: all 0.8s cubic-bezier(0.25, 0.46, 0.45, 0.94); }
.reveal-left.active { opacity: 1; transform: translateX(0); }
.reveal-right { opacity: 0; transform: translateX(60px); transition: all 0.8s cubic-bezier(0.25, 0.46, 0.45, 0.94); }
.reveal-right.active { opacity: 1; transform: translateX(0); }

/* ===== About Section ===== */
.about { background: var(--primary); }
.about-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 4rem; align-items: center; max-width: 1200px; margin: 0 auto;
}
.about-image { position: relative; overflow: hidden; }
.about-image img {
  width: 100%; height: 500px; object-fit: cover;
  transition: transform 0.6s;
}
.about-image:hover img { transform: scale(1.05); }
.about-image-badge {
  position: absolute; bottom: 2rem; right: 2rem;
  background: var(--gold); color: var(--primary);
  padding: 1rem 1.5rem; text-align: center;
}
.about-image-badge .num { font-family: var(--font-en-title); font-size: 2.5rem; font-weight: 700; line-height: 1; }
.about-image-badge .label { font-size: 0.75rem; letter-spacing: 1px; }

.about-text h3 {
  font-family: var(--font-zh-title); font-size: 1.8rem;
  margin-bottom: 1.5rem; line-height: 1.5;
}
.about-text p { color: var(--text-muted); margin-bottom: 1.5rem; font-size: 0.95rem; line-height: 2; }

.stats { display: flex; gap: 2rem; margin-top: 2.5rem; flex-wrap: wrap; }
.stat { text-align: center; flex: 1; min-width: 100px; }
.stat .number {
  font-family: var(--font-en-title); font-size: 2.5rem;
  font-weight: 700; color: var(--gold); line-height: 1;
}
.stat .unit { font-size: 1rem; color: var(--gold); }
.stat .desc { font-size: 0.8rem; color: var(--text-muted); margin-top: 0.3rem; }

/* ===== Products Section ===== */
.products { background: linear-gradient(180deg, var(--primary) 0%, #151528 100%); }
.products-grid {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem; max-width: 1200px; margin: 0 auto;
}
.product-card {
  position: relative; overflow: hidden; cursor: pointer;
  aspect-ratio: 4/5; group: true;
}
.product-card img {
  width: 100%; height: 100%; object-fit: cover;
  transition: transform 0.6s, filter 0.6s;
}
.product-card:hover img { transform: scale(1.1); filter: brightness(0.7); }
.product-card-overlay {
  position: absolute; inset: 0;
  background: linear-gradient(to top, rgba(26,26,46,0.9) 0%, transparent 60%);
  display: flex; flex-direction: column; justify-content: flex-end;
  padding: 2rem; transition: var(--transition);
}
.product-card:hover .product-card-overlay {
  background: linear-gradient(to top, rgba(26,26,46,0.95) 0%, rgba(26,26,46,0.3) 100%);
}
.product-card-title {
  font-family: var(--font-zh-title); font-size: 1.3rem;
  font-weight: 600; margin-bottom: 0.3rem;
}
.product-card-subtitle {
  font-family: var(--font-en-title); font-style: italic;
  font-size: 0.85rem; color: var(--gold);
}
.product-card-desc {
  font-size: 0.85rem; color: var(--text-muted); line-height: 1.6;
  max-height: 0; overflow: hidden; margin-top: 0;
  transition: all 0.4s;
}
.product-card:hover .product-card-desc { max-height: 100px; margin-top: 0.8rem; }
.product-card-arrow {
  position: absolute; top: 1.5rem; right: 1.5rem;
  width: 40px; height: 40px; border: 1px solid var(--gold);
  display: flex; align-items: center; justify-content: center;
  color: var(--gold); font-size: 1.2rem;
  opacity: 0; transform: translate(10px, -10px);
  transition: var(--transition);
}
.product-card:hover .product-card-arrow { opacity: 1; transform: translate(0,0); }

/* ===== Cases Section ===== */
.cases { background: var(--primary); }
.cases-carousel {
  position: relative; max-width: 1200px; margin: 0 auto;
  overflow: hidden;
}
.cases-track { display: flex; transition: transform 0.6s cubic-bezier(0.25, 0.46, 0.45, 0.94); }
.case-slide {
  min-width: 100%; position: relative;
  aspect-ratio: 16/9; overflow: hidden;
}
.case-slide img { width: 100%; height: 100%; object-fit: cover; }
.case-slide-info {
  position: absolute; bottom: 0; left: 0; right: 0;
  padding: 3rem; background: linear-gradient(to top, rgba(26,26,46,0.95), transparent);
}
.case-slide-info h3 { font-family: var(--font-zh-title); font-size: 1.6rem; margin-bottom: 0.5rem; }
.case-slide-info p { color: var(--text-muted); font-size: 0.9rem; }
.case-tag {
  display: inline-block; border: 1px solid var(--gold);
  color: var(--gold); padding: 0.2rem 0.8rem;
  font-size: 0.75rem; margin-right: 0.5rem; margin-top: 0.5rem;
}

.cases-nav {
  display: flex; justify-content: center; gap: 1rem;
  margin-top: 2rem;
}
.cases-nav button {
  width: 50px; height: 50px; border: 1px solid var(--gold);
  background: transparent; color: var(--gold);
  font-size: 1.2rem; cursor: pointer; transition: var(--transition);
}
.cases-nav button:hover { background: var(--gold); color: var(--primary); }

/* ===== Advantages Section ===== */
.advantages { background: linear-gradient(180deg, #151528 0%, var(--primary) 100%); }
.adv-grid {
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 2rem; max-width: 1200px; margin: 0 auto 4rem;
}
.adv-card {
  text-align: center; padding: 2.5rem 1.5rem;
  border: 1px solid rgba(201,169,110,0.15);
  transition: var(--transition); position: relative; overflow: hidden;
}
.adv-card::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, rgba(201,169,110,0.05), transparent);
  opacity: 0; transition: var(--transition);
}
.adv-card:hover { border-color: var(--gold); transform: translateY(-5px); }
.adv-card:hover::before { opacity: 1; }
.adv-icon {
  font-size: 2.5rem; margin-bottom: 1.2rem;
  color: var(--gold);
}
.adv-card h4 { font-family: var(--font-zh-title); font-size: 1.1rem; margin-bottom: 0.8rem; }
.adv-card p { font-size: 0.85rem; color: var(--text-muted); line-height: 1.7; }

/* Process Timeline */
.process { max-width: 1000px; margin: 0 auto; }
.process-title { text-align: center; margin-bottom: 3rem; }
.process-title h3 { font-family: var(--font-zh-title); font-size: 1.5rem; }
.process-steps {
  display: flex; justify-content: space-between;
  position: relative; padding: 2rem 0;
}
.process-steps::before {
  content: ''; position: absolute; top: 50%;
  left: 5%; right: 5%; height: 1px;
  background: linear-gradient(90deg, var(--gold), var(--gold-light), var(--gold));
}
.process-step {
  text-align: center; position: relative; z-index: 1; flex: 1;
}
.process-step-num {
  width: 50px; height: 50px; margin: 0 auto 1rem;
  background: var(--primary); border: 2px solid var(--gold);
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-en-title); font-size: 1.1rem;
  color: var(--gold); font-weight: 600;
  transition: var(--transition);
}
.process-step:hover .process-step-num { background: var(--gold); color: var(--primary); }
.process-step-label { font-size: 0.85rem; color: var(--text-muted); }

/* ===== Testimonials Section ===== */
.testimonials { background: var(--primary); }
.test-grid {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 2rem; max-width: 1200px; margin: 0 auto;
}
.test-card {
  padding: 2.5rem; border: 1px solid rgba(201,169,110,0.1);
  background: rgba(45,45,63,0.5); transition: var(--transition);
}
.test-card:hover { border-color: var(--gold); transform: translateY(-3px); }
.test-stars { color: var(--gold); font-size: 0.9rem; margin-bottom: 1rem; letter-spacing: 3px; }
.test-text { font-size: 0.9rem; color: var(--text-muted); line-height: 1.8; margin-bottom: 1.5rem; font-style: italic; }
.test-author { display: flex; align-items: center; gap: 1rem; }
.test-avatar {
  width: 45px; height: 45px; border-radius: 50%;
  background: var(--gold); display: flex; align-items: center; justify-content: center;
  font-weight: 700; color: var(--primary); font-size: 1rem;
}
.test-info .name { font-weight: 600; font-size: 0.9rem; }
.test-info .role { font-size: 0.75rem; color: var(--text-muted); }

/* ===== Contact Section ===== */
.contact { background: linear-gradient(180deg, var(--primary) 0%, #12121f 100%); }
.contact-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 4rem; max-width: 1200px; margin: 0 auto;
}
.contact-info h3 { font-family: var(--font-zh-title); font-size: 1.5rem; margin-bottom: 1.5rem; }
.contact-info p { color: var(--text-muted); margin-bottom: 2rem; font-size: 0.9rem; }
.contact-item {
  display: flex; gap: 1rem; margin-bottom: 1.5rem; align-items: flex-start;
}
.contact-item-icon {
  width: 40px; height: 40px; border: 1px solid var(--gold);
  display: flex; align-items: center; justify-content: center;
  color: var(--gold); font-size: 1rem; flex-shrink: 0;
}
.contact-item-text .label { font-size: 0.75rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 1px; }
.contact-item-text .value { font-size: 0.95rem; margin-top: 0.2rem; }

.contact-form { display: flex; flex-direction: column; gap: 1.2rem; }
.form-row { display: flex; gap: 1.2rem; }
.form-group { flex: 1; display: flex; flex-direction: column; }
.form-group label { font-size: 0.8rem; color: var(--text-muted); margin-bottom: 0.4rem; letter-spacing: 0.5px; }
.form-group input, .form-group textarea, .form-group select {
  background: rgba(45,45,63,0.6); border: 1px solid rgba(201,169,110,0.2);
  padding: 0.9rem 1rem; color: var(--text-light);
  font-family: var(--font-body); font-size: 0.9rem;
  transition: border-color 0.3s; outline: none;
}
.form-group input:focus, .form-group textarea:focus, .form-group select:focus { border-color: var(--gold); }
.form-group textarea { resize: vertical; min-height: 120px; }
.form-submit {
  background: linear-gradient(135deg, var(--gold), #b8944f);
  color: var(--primary); border: none; padding: 1rem 2.5rem;
  font-size: 0.95rem; font-weight: 600; cursor: pointer;
  letter-spacing: 1px; transition: var(--transition);
  font-family: var(--font-body); align-self: flex-start;
}
.form-submit:hover { transform: translateY(-2px); box-shadow: 0 10px 30px rgba(201,169,110,0.3); }

/* ===== Footer ===== */
.footer {
  background: #0d0d18; padding: 3rem 4% 1.5rem;
  border-top: 1px solid rgba(201,169,110,0.1);
}
.footer-top {
  display: flex; justify-content: space-between; align-items: center;
  max-width: 1200px; margin: 0 auto; padding-bottom: 2rem;
  border-bottom: 1px solid rgba(201,169,110,0.1);
}
.footer-social { display: flex; gap: 1rem; }
.footer-social a {
  width: 40px; height: 40px; border: 1px solid rgba(201,169,110,0.3);
  display: flex; align-items: center; justify-content: center;
  color: var(--gold); text-decoration: none; font-size: 1rem;
  transition: var(--transition);
}
.footer-social a:hover { background: var(--gold); color: var(--primary); }
.footer-bottom {
  text-align: center; padding-top: 1.5rem;
  max-width: 1200px; margin: 0 auto;
}
.footer-bottom p { font-size: 0.8rem; color: var(--text-muted); }

/* ===== Mobile Menu ===== */
.mobile-menu {
  display: none; position: fixed; inset: 0; z-index: 999;
  background: rgba(26,26,46,0.98); backdrop-filter: blur(20px);
  flex-direction: column; align-items: center; justify-content: center;
  gap: 2rem;
}
.mobile-menu.open { display: flex; }
.mobile-menu a {
  font-family: var(--font-zh-title); font-size: 1.5rem;
  color: var(--text-light); text-decoration: none;
  transition: color 0.3s;
}
.mobile-menu a:hover { color: var(--gold); }
.mobile-close {
  position: absolute; top: 1.5rem; right: 1.5rem;
  background: none; border: none; color: var(--text-light);
  font-size: 2rem; cursor: pointer;
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .products-grid { grid-template-columns: repeat(2, 1fr); }
  .adv-grid { grid-template-columns: repeat(2, 1fr); }
  .test-grid { grid-template-columns: 1fr; max-width: 600px; }
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-toggle { display: flex; }
  .hero-title { font-size: 1.8rem; }
  .about-grid { grid-template-columns: 1fr; gap: 2rem; }
  .about-image img { height: 350px; }
  .products-grid { grid-template-columns: 1fr; max-width: 500px; margin: 0 auto; }
  .contact-grid { grid-template-columns: 1fr; }
  .form-row { flex-direction: column; }
  .adv-grid { grid-template-columns: 1fr; max-width: 400px; margin: 0 auto 4rem; }
  .process-steps { flex-direction: column; gap: 1.5rem; align-items: center; }
  .process-steps::before { display: none; }
  .footer-top { flex-direction: column; gap: 1.5rem; text-align: center; }
  .stats { justify-content: center; }
  .section { padding: 4rem 5%; }
}