/* ==========================================
   彼威达管理咨询（北京）有限公司 官网样式
   BVDA Management Consulting (Beijing) Co., Ltd.
   ========================================== */

/* ----- CSS Variables / Design Tokens ----- */
:root {
  --color-primary: #1a3c6e;
  --color-primary-light: #2d5fa0;
  --color-primary-dark: #0f2442;
  --color-accent: #c8a84e;
  --color-accent-light: #e8d5a0;
  --color-white: #ffffff;
  --color-black: #1a1a1a;
  --color-gray-50: #f8f9fa;
  --color-gray-100: #f1f3f5;
  --color-gray-200: #e9ecef;
  --color-gray-300: #dee2e6;
  --color-gray-400: #adb5bd;
  --color-gray-500: #6c757d;
  --color-gray-600: #495057;
  --color-gray-700: #343a40;
  --color-gray-800: #212529;

  --font-heading: 'Microsoft YaHei', 'PingFang SC', 'Helvetica Neue', sans-serif;
  --font-body: 'Microsoft YaHei', 'PingFang SC', 'Helvetica Neue', Arial, sans-serif;

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.12);

  --max-width: 1200px;
  --header-height: 80px;
  --radius: 6px;
  --transition: 0.3s ease;
}

/* ----- Reset & Base ----- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-body);
  color: var(--color-gray-700);
  background: var(--color-white);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-primary-light);
  text-decoration: none;
  transition: color var(--transition);
}
a:hover { color: var(--color-primary); }

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

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--color-gray-800);
  line-height: 1.3;
}

/* ----- Utility Classes ----- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 100px 0;
}

.section-light { background: var(--color-gray-50); }
.section-dark { background: var(--color-primary); color: var(--color-white); }
.section-dark h1, .section-dark h2, .section-dark h3 { color: var(--color-white); }

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-header h2 {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--color-primary-dark);
}

.section-header p {
  font-size: 1.1rem;
  color: var(--color-gray-500);
  max-width: 600px;
  margin: 0 auto;
}

.section-header.light h2 { color: var(--color-white); }
.section-header.light p { color: rgba(255,255,255,0.75); }

.btn {
  display: inline-block;
  padding: 14px 36px;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  border: 2px solid transparent;
  cursor: pointer;
  transition: all var(--transition);
  text-align: center;
  font-family: var(--font-body);
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-white);
  border-color: var(--color-primary);
}
.btn-primary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: var(--color-white);
}

.btn-outline {
  background: transparent;
  border-color: var(--color-white);
  color: var(--color-white);
}
.btn-outline:hover {
  background: var(--color-white);
  color: var(--color-primary);
}

.btn-accent {
  background: var(--color-accent);
  color: var(--color-white);
  border-color: var(--color-accent);
}
.btn-accent:hover {
  background: #b89538;
  border-color: #b89538;
  color: var(--color-white);
}

/* ----- Header / Navigation ----- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--color-white);
  box-shadow: var(--shadow-sm);
  z-index: 1000;
  transition: all var(--transition);
}

.header.scrolled {
  box-shadow: var(--shadow-md);
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-primary);
  font-family: var(--font-heading);
}

.logo-icon {
  width: 44px;
  height: 44px;
  background: var(--color-primary);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-white);
  font-size: 1.2rem;
  font-weight: 700;
}

.nav { display: flex; align-items: center; gap: 4px; }

.nav a {
  display: block;
  padding: 10px 20px;
  font-size: 0.95rem;
  color: var(--color-gray-600);
  font-weight: 500;
  border-radius: var(--radius);
  transition: all var(--transition);
}

.nav a:hover,
.nav a.active {
  color: var(--color-primary);
  background: rgba(26, 60, 110, 0.06);
}

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-primary);
  transition: all var(--transition);
}

/* ----- Hero Section ----- */
.hero {
  padding: 160px 0 120px;
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 50%, var(--color-primary-light) 100%);
  color: var(--color-white);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.hero .container { position: relative; z-index: 1; }

.hero h1 {
  font-size: 3rem;
  font-weight: 700;
  margin-bottom: 24px;
  color: var(--color-white);
  letter-spacing: 0.02em;
}

.hero h1 .highlight { color: var(--color-accent); }

.hero .subtitle {
  font-size: 1.25rem;
  color: rgba(255,255,255,0.85);
  margin-bottom: 20px;
}

.hero .description {
  font-size: 1.1rem;
  color: rgba(255,255,255,0.7);
  max-width: 700px;
  margin: 0 auto 40px;
  line-height: 1.8;
}

.hero .btn-group { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ----- Stats Bar ----- */
.stats-bar {
  background: var(--color-white);
  box-shadow: var(--shadow-md);
  border-radius: 12px;
  padding: 40px;
  margin-top: -60px;
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
}

.stat-item {
  text-align: center;
  padding: 0 16px;
}

.stat-item .stat-number {
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--color-primary);
  font-family: var(--font-heading);
  line-height: 1.2;
}

.stat-item .stat-number span { font-size: 1.5rem; }

.stat-item .stat-label {
  font-size: 0.95rem;
  color: var(--color-gray-500);
  margin-top: 8px;
}

/* ----- About Section ----- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.about-image {
  background: var(--color-gray-100);
  border-radius: 12px;
  height: 400px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.about-image .placeholder {
  text-align: center;
  color: var(--color-gray-400);
}

.about-image .placeholder svg { margin-bottom: 12px; }

.about-text h3 {
  font-size: 1.8rem;
  margin-bottom: 24px;
  color: var(--color-primary-dark);
}

.about-text p {
  font-size: 1.05rem;
  color: var(--color-gray-600);
  margin-bottom: 16px;
}

.about-text .highlight-text {
  padding: 20px 24px;
  background: var(--color-gray-50);
  border-left: 4px solid var(--color-accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 24px 0;
  font-style: italic;
}

/* ----- Services Cards ----- */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
}

.service-card {
  background: var(--color-white);
  border-radius: 12px;
  padding: 40px 32px;
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-gray-200);
}

.service-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.service-card .card-icon {
  width: 56px;
  height: 56px;
  background: var(--color-gray-50);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  font-size: 1.5rem;
}

.service-card h4 {
  font-size: 1.2rem;
  margin-bottom: 12px;
  color: var(--color-primary-dark);
}

.service-card p {
  font-size: 0.95rem;
  color: var(--color-gray-500);
  line-height: 1.7;
}

/* ----- Features List ----- */
.features-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.features-list li {
  padding: 20px 24px;
  background: var(--color-white);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.features-list li .feature-icon {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  background: var(--color-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-white);
  font-size: 1rem;
}

.features-list li h5 { font-size: 1.05rem; margin-bottom: 6px; }
.features-list li p { font-size: 0.9rem; color: var(--color-gray-500); }

/* ----- Dimensions Grid ----- */
.dimensions-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.dimension-card {
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 10px;
  padding: 30px 24px;
  text-align: center;
  transition: all var(--transition);
}

.dimension-card:hover {
  background: rgba(255,255,255,0.14);
  transform: translateY(-3px);
}

.dimension-card .dim-icon {
  font-size: 2rem;
  margin-bottom: 12px;
}

.dimension-card h4 {
  font-size: 1.1rem;
  color: var(--color-white);
  margin-bottom: 8px;
}

.dimension-card .dim-en { 
  font-size: 0.8rem; 
  color: var(--color-accent-light); 
  margin-bottom: 8px;
}

.dimension-card p {
  font-size: 0.9rem;
  color: rgba(255,255,255,0.7);
}

/* ----- Timeline (Cases) ----- */
.timeline {
  position: relative;
  padding-left: 40px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 15px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-gray-300);
}

.timeline-item {
  position: relative;
  margin-bottom: 32px;
  padding: 24px 28px;
  background: var(--color-white);
  border-radius: 10px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-gray-200);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -33px;
  top: 32px;
  width: 12px;
  height: 12px;
  background: var(--color-primary);
  border-radius: 50%;
  border: 3px solid var(--color-white);
  box-shadow: 0 0 0 2px var(--color-primary);
}

.timeline-item .case-date {
  font-size: 0.85rem;
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: 6px;
}

.timeline-item h3 {
  font-size: 1.1rem;
  color: var(--color-primary-dark);
}

/* ----- Contact Section ----- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
}

.contact-info h3 {
  font-size: 1.6rem;
  margin-bottom: 20px;
}

.contact-info p {
  font-size: 1.05rem;
  color: var(--color-gray-600);
  margin-bottom: 32px;
}

.contact-methods {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.contact-method {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.contact-method .method-icon {
  width: 48px;
  height: 48px;
  background: var(--color-gray-50);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  flex-shrink: 0;
}

.contact-method h5 {
  font-size: 1rem;
  margin-bottom: 4px;
}

.contact-method span {
  font-size: 0.95rem;
  color: var(--color-gray-500);
}

.contact-form {
  background: var(--color-white);
  padding: 40px;
  border-radius: 12px;
  box-shadow: var(--shadow-md);
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-gray-700);
  margin-bottom: 8px;
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--color-gray-300);
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-family: var(--font-body);
  transition: border-color var(--transition);
  background: var(--color-gray-50);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-primary-light);
  background: var(--color-white);
  box-shadow: 0 0 0 3px rgba(26, 60, 110, 0.08);
}

.form-group textarea { resize: vertical; min-height: 120px; }

/* ----- CTA Section ----- */
.cta-section {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.cta-section h2 {
  font-size: 2rem;
  color: var(--color-white);
  margin-bottom: 16px;
}

.cta-section p {
  font-size: 1.1rem;
  color: rgba(255,255,255,0.8);
  margin-bottom: 32px;
}

/* ----- Footer ----- */
.footer {
  background: var(--color-primary-dark);
  color: rgba(255,255,255,0.7);
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-col h4 {
  color: var(--color-white);
  font-size: 1rem;
  margin-bottom: 20px;
  font-weight: 600;
}

.footer-col p { font-size: 0.9rem; margin-bottom: 12px; line-height: 1.7; }

.footer-col a {
  display: block;
  font-size: 0.9rem;
  color: rgba(255,255,255,0.6);
  margin-bottom: 10px;
  transition: color var(--transition);
}

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

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: rgba(255,255,255,0.5);
}

/* ----- Page Banner (Inner Pages) ----- */
.page-banner {
  padding: 140px 0 80px;
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
  color: var(--color-white);
  text-align: center;
}

.page-banner h1 {
  font-size: 2.6rem;
  color: var(--color-white);
  margin-bottom: 12px;
}

.page-banner p {
  font-size: 1.1rem;
  color: rgba(255,255,255,0.7);
}

/* ----- Our Philosophy ----- */
.philosophy-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
}

.philosophy-card {
  text-align: center;
  padding: 40px 28px;
  background: var(--color-white);
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-gray-200);
  transition: all var(--transition);
}

.philosophy-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.philosophy-card .phil-icon {
  width: 64px;
  height: 64px;
  background: var(--color-gray-50);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
  font-size: 1.8rem;
}

.philosophy-card h4 { font-size: 1.15rem; margin-bottom: 12px; }
.philosophy-card p { color: var(--color-gray-500); font-size: 0.95rem; }

/* ----- Process Steps ----- */
.process-steps {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.process-step {
  flex: 1;
  min-width: 150px;
  text-align: center;
  padding: 24px 16px;
  background: rgba(255,255,255,0.08);
  border-radius: 10px;
  border: 1px solid rgba(255,255,255,0.12);
  position: relative;
}

.process-step .step-num {
  width: 40px;
  height: 40px;
  background: var(--color-accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 12px;
  font-weight: 700;
  color: var(--color-white);
  font-size: 1.1rem;
}

.process-step h5 { color: var(--color-white); font-size: 0.95rem; }

.process-step:not(:last-child)::after {
  content: '\2192';
  position: absolute;
  right: -18px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--color-accent);
  font-size: 1.3rem;
  font-weight: 700;
}

/* ----- Animate On Scroll ----- */
.animate { 
  opacity: 0; 
  transform: translateY(30px); 
  transition: all 0.6s ease; 
}

.animate.visible { 
  opacity: 1; 
  transform: translateY(0); 
}

/* ----- Responsive ----- */
@media (max-width: 1024px) {
  .services-grid { grid-template-columns: repeat(2, 1fr); }
  .dimensions-grid { grid-template-columns: repeat(2, 1fr); }
  .philosophy-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .stats-bar { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: 1fr; }
  .about-grid { grid-template-columns: 1fr; }
  .about-image { height: 300px; }
}

@media (max-width: 768px) {
  .hero h1 { font-size: 2rem; }
  .section-header h2 { font-size: 1.6rem; }
  .section { padding: 60px 0; }
  .services-grid { grid-template-columns: 1fr; }
  .dimensions-grid { grid-template-columns: 1fr; }
  .philosophy-grid { grid-template-columns: 1fr; }
  .features-list { grid-template-columns: 1fr; }
  .stats-bar { grid-template-columns: 1fr; gap: 20px; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: 8px; text-align: center; }
  .page-banner { padding: 120px 0 60px; }
  .page-banner h1 { font-size: 2rem; }
  .process-steps { flex-direction: column; }
  .process-step:not(:last-child)::after { display: none; }

  .nav { 
    display: none; 
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-white);
    flex-direction: column;
    padding: 16px;
    box-shadow: var(--shadow-md);
  }
  .nav.active { display: flex; }
  .menu-toggle { display: flex; }
}