/* ============================================
   ExCentre.cn - SEO Optimized Stylesheet
   Mobile-First Responsive Design
   ============================================ */

/* ---- CSS Variables ---- */
:root {
  --color-primary: #1a56db;
  --color-primary-dark: #1342b0;
  --color-secondary: #0f172a;
  --color-accent: #f59e0b;
  --color-success: #10b981;
  --color-danger: #ef4444;
  --color-bg: #ffffff;
  --color-bg-alt: #f8fafc;
  --color-bg-dark: #0f172a;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-border: #e2e8f0;
  --color-border-light: #f1f5f9;
  --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 10px 30px rgba(0,0,0,0.12);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --transition: all 0.3s ease;
  --container: 1200px;
}

/* ---- Reset & Base ---- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--color-primary); text-decoration: none; transition: var(--transition); }
a:hover { color: var(--color-primary-dark); text-decoration: underline; }
ul, ol { list-style: none; }
button { cursor: pointer; border: none; outline: none; font-family: inherit; }

/* ---- Layout ---- */
.container { max-width: var(--container); margin: 0 auto; padding: 0 20px; }
.section { padding: 60px 0; }
.section-alt { background: var(--color-bg-alt); }

/* ---- Typography ---- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-secondary);
}
h1 { font-size: clamp(1.8rem, 4vw, 2.5rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2rem); }
h3 { font-size: clamp(1.2rem, 2.5vw, 1.5rem); }
p { margin-bottom: 1rem; color: var(--color-text); }

/* ---- Breadcrumb ---- */
.breadcrumb {
  background: var(--color-bg-alt);
  border-bottom: 1px solid var(--color-border);
  padding: 10px 0;
}
.breadcrumb .container { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.breadcrumb a { color: var(--color-text-muted); font-size: 0.875rem; }
.breadcrumb a:hover { color: var(--color-primary); text-decoration: none; }
.breadcrumb span { color: var(--color-text-muted); font-size: 0.875rem; }
.breadcrumb .current { color: var(--color-secondary); font-weight: 500; }

/* ---- Header ---- */
.header {
  background: var(--color-bg);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 1000;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  max-width: var(--container);
  margin: 0 auto;
}
.logo { display: flex; align-items: center; gap: 10px; font-weight: 900; font-size: 1.5rem; color: #000000; text-decoration: none; letter-spacing: -0.5px; }
.logo:hover { text-decoration: none; color: #333333; }
.logo-icon { display: none; }

/* Nav */
.nav { display: flex; align-items: center; gap: 4px; }
.nav a {
  padding: 8px 14px;
  color: var(--color-text);
  font-size: 0.9rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: var(--transition);
}
.nav a:hover, .nav a.active { background: var(--color-primary); color: #fff; text-decoration: none; }
.nav-cta {
  background: var(--color-accent) !important;
  color: var(--color-secondary) !important;
  font-weight: 700 !important;
  border-radius: var(--radius-sm) !important;
}

/* Mobile menu toggle */
.menu-toggle { display: none; background: none; padding: 8px; }
.menu-toggle svg { width: 24px; height: 24px; fill: var(--color-secondary); }

/* ---- Hero ---- */
.hero {
  background: #ffffff;
  color: var(--color-text);
  padding: 60px 0 40px;
  text-align: center;
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--color-border);
}
.hero .container { position: relative; z-index: 1; }
.hero h1 { color: var(--color-secondary); margin-bottom: 20px; font-size: clamp(2rem, 5vw, 3rem); }
.hero p { color: var(--color-text-muted); font-size: 1.1rem; max-width: 700px; margin: 0 auto 30px; }
.hero-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 1rem;
  text-decoration: none;
  transition: var(--transition);
  border: 2px solid transparent;
  white-space: nowrap;
}
.btn-primary {
  background: var(--color-accent);
  color: var(--color-secondary);
  border-color: var(--color-accent);
}
.btn-primary:hover { background: #d97706; border-color: #d97706; color: #fff; text-decoration: none; }
.btn-secondary {
  background: transparent;
  color: #fff;
  border-color: rgba(255,255,255,0.5);
}
.btn-secondary:hover { background: rgba(255,255,255,0.1); border-color: #fff; color: #fff; text-decoration: none; }
.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.btn-outline:hover { background: var(--color-primary); color: #fff; text-decoration: none; }

/* ---- Stats ---- */
.stats { background: var(--color-secondary); padding: 40px 0; }
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 20px;
}
.stat-item { text-align: center; color: #fff; }
.stat-value { font-size: clamp(1.5rem, 3vw, 2.2rem); font-weight: 800; color: var(--color-accent); }
.stat-label { font-size: 0.85rem; color: rgba(255,255,255,0.7); margin-top: 4px; }

/* ---- Features ---- */
.features { padding: 60px 0; }
.section-header { text-align: center; margin-bottom: 40px; }
.section-header h2 { margin-bottom: 12px; }
.section-header p { color: var(--color-text-muted); max-width: 600px; margin: 0 auto; }
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.feature-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  transition: var(--transition);
}
.feature-card:hover { box-shadow: var(--shadow-md); transform: translateY(-4px); border-color: var(--color-primary); }
.feature-icon {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, #dbeafe, #eff6ff);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  font-size: 1.5rem;
}
.feature-card h3 { font-size: 1.1rem; margin-bottom: 8px; }
.feature-card p { font-size: 0.9rem; color: var(--color-text-muted); margin: 0; }

/* ---- Trading Platforms ---- */
.platforms { padding: 60px 0; }
.platforms-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.platform-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: var(--transition);
}
.platform-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-4px); }
.platform-card h3 { font-size: 1.2rem; margin-bottom: 8px; }
.platform-card p { font-size: 0.9rem; color: var(--color-text-muted); }
.platform-header { padding: 24px; background: linear-gradient(135deg, #f0f9ff, #e0f2fe); }
.platform-header.mt5 { background: linear-gradient(135deg, #f0fdf4, #dcfce7); }
.platform-tags { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 12px; }
.platform-tag {
  background: var(--color-primary);
  color: #fff;
  padding: 2px 10px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
}
.platform-tag.mt5-tag { background: var(--color-success); }
.platform-body { padding: 24px; }
.platform-feature-list { display: flex; flex-direction: column; gap: 8px; margin: 16px 0; }
.platform-feature-list li {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--color-text);
}
.platform-feature-list li::before {
  content: '✓';
  color: var(--color-success);
  font-weight: 700;
  flex-shrink: 0;
  margin-top: 1px;
}
.platform-download { margin-top: 16px; }

/* ---- Trading Instruments ---- */
.instruments { padding: 60px 0; background: var(--color-bg-alt); }
.instruments-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.instrument-item {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--color-bg);
  padding: 16px 20px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  transition: var(--transition);
}
.instrument-item:hover { border-color: var(--color-primary); box-shadow: var(--shadow-sm); }
.instrument-icon { width: 40px; height: 40px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 1.2rem; flex-shrink: 0; }
.instrument-name { font-weight: 600; font-size: 0.95rem; color: var(--color-secondary); }
.instrument-desc { font-size: 0.8rem; color: var(--color-text-muted); }

/* ---- Account Types ---- */
.accounts { padding: 60px 0; }
.accounts-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.account-card {
  background: var(--color-bg);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: var(--transition);
  position: relative;
}
.account-card:hover { box-shadow: var(--shadow-lg); border-color: var(--color-primary); }
.account-card.pro { border-color: var(--color-primary); }
.account-badge {
  position: absolute;
  top: -12px;
  right: 20px;
  background: var(--color-primary);
  color: #fff;
  padding: 4px 14px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 700;
}
.account-card h3 { font-size: 1.3rem; margin-bottom: 8px; }
.account-card .account-subtitle { color: var(--color-text-muted); margin-bottom: 16px; font-size: 0.9rem; }
.account-feature-list { display: flex; flex-direction: column; gap: 10px; margin: 20px 0; }
.account-feature-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--color-text);
}
.account-feature-list li::before {
  content: '✓';
  color: var(--color-success);
  font-weight: 700;
  flex-shrink: 0;
  margin-top: 1px;
}
.account-cta { margin-top: 20px; }

/* ---- CTA Banner ---- */
.cta-banner {
  background: linear-gradient(135deg, var(--color-secondary), #1e293b);
  padding: 60px 0;
  text-align: center;
  color: #fff;
}
.cta-banner h2 { color: #fff; margin-bottom: 16px; }
.cta-banner p { color: rgba(255,255,255,0.8); max-width: 600px; margin: 0 auto 30px; }

/* ---- FAQ ---- */
.faq { padding: 60px 0; }
.faq-list { max-width: 800px; margin: 0 auto; display: flex; flex-direction: column; gap: 12px; }
.faq-item {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}
.faq-item:hover { border-color: var(--color-primary); }
.faq-question {
  width: 100%;
  background: none;
  padding: 18px 24px;
  text-align: left;
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-secondary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  cursor: pointer;
}
.faq-question::after {
  content: '+';
  font-size: 1.4rem;
  color: var(--color-primary);
  font-weight: 700;
  flex-shrink: 0;
  transition: transform 0.3s ease;
}
.faq-item.active .faq-question::after { transform: rotate(45deg); }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}
.faq-answer-inner {
  padding: 0 24px 18px;
  color: var(--color-text-muted);
  font-size: 0.95rem;
  line-height: 1.8;
}

/* ---- Comparison Table ---- */
.compare-table-wrapper { overflow-x: auto; }
.compare-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--color-bg);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
.compare-table th {
  background: var(--color-primary);
  color: #fff;
  padding: 14px 20px;
  text-align: left;
  font-weight: 600;
  font-size: 0.9rem;
}
.compare-table td {
  padding: 12px 20px;
  border-bottom: 1px solid var(--color-border-light);
  font-size: 0.9rem;
  color: var(--color-text);
}
.compare-table tr:last-child td { border-bottom: none; }
.compare-table tr:hover td { background: var(--color-bg-alt); }
.compare-table .highlight { background: #f0f9ff; font-weight: 600; color: var(--color-primary); }

/* ---- Steps ---- */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.step { text-align: center; }
.step-number {
  width: 48px;
  height: 48px;
  background: var(--color-primary);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  font-weight: 800;
  margin: 0 auto 12px;
}
.step h3 { font-size: 1rem; margin-bottom: 6px; }
.step p { font-size: 0.85rem; color: var(--color-text-muted); margin: 0; }

/* ---- Content Section ---- */
.content-section { padding: 60px 0; }
.content-section h2 { margin-bottom: 20px; }
.content-section p { color: var(--color-text-muted); max-width: 900px; }
.content-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 32px; margin-top: 32px; }
.content-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
}
.content-card h3 { margin-bottom: 12px; }
.content-card p { color: var(--color-text-muted); font-size: 0.9rem; margin-bottom: 0; }

/* ---- Signup Form ---- */
.signup-section { padding: 60px 0; }
.signup-form {
  max-width: 520px;
  margin: 0 auto;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-md);
}
.form-group { margin-bottom: 20px; }
.form-group label { display: block; font-weight: 600; font-size: 0.9rem; margin-bottom: 6px; color: var(--color-secondary); }
.form-group input,
.form-group select {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-family: inherit;
  color: var(--color-text);
  background: var(--color-bg);
  transition: var(--transition);
}
.form-group input:focus,
.form-group select:focus {
  border-color: var(--color-primary);
  outline: none;
  box-shadow: 0 0 0 3px rgba(26,86,219,0.1);
}
.form-hint { font-size: 0.8rem; color: var(--color-text-muted); margin-top: 4px; }
.form-error { font-size: 0.8rem; color: var(--color-danger); margin-top: 4px; }
.form-checkbox { display: flex; align-items: flex-start; gap: 10px; }
.form-checkbox input[type="checkbox"] { width: auto; margin-top: 3px; flex-shrink: 0; }
.form-checkbox label { font-size: 0.85rem; color: var(--color-text-muted); line-height: 1.5; margin-bottom: 0; }
.form-submit { width: 100%; margin-top: 8px; }

/* ---- Related Pages ---- */
.related { padding: 60px 0; background: var(--color-bg-alt); }
.related-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.related-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 20px;
  transition: var(--transition);
  text-decoration: none;
  display: block;
}
.related-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); border-color: var(--color-primary); text-decoration: none; }
.related-card h3 { font-size: 1rem; margin-bottom: 6px; color: var(--color-secondary); }
.related-card p { font-size: 0.85rem; color: var(--color-text-muted); margin: 0; }

/* ---- Footer ---- */
.footer {
  background: var(--color-secondary);
  color: rgba(255,255,255,0.7);
  padding: 50px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 20px;
}
.footer-brand p { color: rgba(255,255,255,0.5); font-size: 0.85rem; margin-top: 12px; line-height: 1.7; }
.footer h4 { color: #fff; font-size: 1rem; margin-bottom: 16px; font-weight: 600; }
.footer-links { display: flex; flex-direction: column; gap: 10px; }
.footer-links a { color: rgba(255,255,255,0.6); font-size: 0.875rem; text-decoration: none; transition: var(--transition); }
.footer-links a:hover { color: #fff; text-decoration: none; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding: 20px;
  text-align: center;
  margin-top: 40px;
  font-size: 0.8rem;
  color: rgba(255,255,255,0.4);
}
.footer-bottom-links { display: flex; gap: 20px; justify-content: center; margin-bottom: 10px; }
.footer-bottom-links a { color: rgba(255,255,255,0.4); font-size: 0.8rem; text-decoration: none; }
.footer-bottom-links a:hover { color: rgba(255,255,255,0.8); text-decoration: none; }

/* ---- Article Content ---- */
.article-content { max-width: 800px; margin: 0 auto; }
.article-content h2 { margin: 32px 0 16px; font-size: 1.5rem; }
.article-content h3 { margin: 24px 0 12px; font-size: 1.2rem; }
.article-content p { color: var(--color-text-muted); margin-bottom: 16px; line-height: 1.9; }
.article-content ul { margin: 16px 0; padding-left: 24px; }
.article-content ul li { list-style: disc; margin-bottom: 8px; color: var(--color-text-muted); line-height: 1.8; }
.article-content strong { color: var(--color-secondary); }
.article-warning {
  background: #fef3c7;
  border-left: 4px solid var(--color-accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 16px 20px;
  margin: 24px 0;
}
.article-warning h4 { font-size: 0.95rem; margin-bottom: 6px; color: #92400e; }
.article-warning p { font-size: 0.9rem; color: #92400e; margin: 0; }

/* ---- Responsive ---- */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .menu-toggle { display: block; }
  .nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-bg);
    flex-direction: column;
    padding: 16px;
    border-top: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
    gap: 4px;
  }
  .nav.open { display: flex; }
  .nav a { width: 100%; text-align: center; padding: 12px; }
  .header { position: relative; }
  .header-inner { padding: 12px 16px; }
  .features-grid { grid-template-columns: 1fr; }
  .platforms-grid { grid-template-columns: 1fr; }
  .accounts-grid { grid-template-columns: 1fr; }
  .instruments-grid { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr; gap: 24px; }
  .related-grid { grid-template-columns: 1fr; }
  .content-grid { grid-template-columns: 1fr; }
  .section { padding: 40px 0; }
  .hero { padding: 50px 0 40px; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .signup-form { padding: 24px; }
}
@media (max-width: 480px) {
  .instruments-grid { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
  .hero-actions { flex-direction: column; align-items: center; }
  .btn { width: 100%; justify-content: center; }
}