/* ===================== 鑫源国际贸易 / StarLink Trading ===================== */

/* ---------- 设计令牌 ---------- */
:root {
  --color-primary: #0f2b46;
  --color-primary-dark: #0a1f33;
  --color-accent: #e59a2e;
  --color-bg: #f7f9fb;
  --color-surface: #ffffff;
  --color-text: #1f2937;
  --color-text-muted: #6b7280;
  --color-border: #e5e7eb;
  --color-white: #ffffff;

  --font-sans: -apple-system, "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Segoe UI", sans-serif;
  --font-en: "Inter", -apple-system, "Segoe UI", sans-serif;

  --font-size-body: 16px;
  --font-size-h1: clamp(32px, 5vw, 46px);
  --font-size-h2: clamp(26px, 4vw, 34px);
  --font-size-h3: 20px;

  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 32px;
  --space-xl: 64px;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  --shadow-card: 0 4px 16px rgba(15, 43, 70, 0.06);
  --shadow-btn: 0 4px 12px rgba(229, 154, 46, 0.3);

  --container-max: 1200px;
  --header-height: 64px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  font-size: var(--font-size-body);
  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: color 0.2s; }
a:hover { color: var(--color-accent); }
ul { list-style: none; }

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 15px;
  text-align: center;
  cursor: pointer;
  transition: all 0.25s;
  border: 2px solid transparent;
}
.btn-lg { padding: 14px 36px; font-size: 17px; }
.btn-accent {
  background: var(--color-accent);
  color: var(--color-white);
  border-color: var(--color-accent);
  box-shadow: var(--shadow-btn);
}
.btn-accent:hover { background: #d48c1f; border-color: #d48c1f; color: var(--color-white); }
.btn-outline {
  background: transparent;
  color: var(--color-white);
  border-color: var(--color-white);
}
.btn-outline:hover { background: var(--color-white); color: var(--color-primary); }

/* ---------- Section 通用 ---------- */
.section {
  padding: var(--space-xl) 0;
}
.section-title {
  font-size: var(--font-size-h2);
  font-weight: 700;
  color: var(--color-primary);
  text-align: center;
  margin-bottom: var(--space-sm);
}
.section-desc {
  text-align: center;
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

/* ===================== 顶栏 + 导航 ===================== */
.topbar {
  background: var(--color-primary-dark);
  color: rgba(255,255,255,0.75);
  font-size: 13px;
  padding: 6px 0;
}
.topbar-inner {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  flex-wrap: wrap;
}
.topbar-lang {
  margin-left: auto;
  color: var(--color-accent);
  font-weight: 600;
}
.topbar-lang:hover { color: var(--color-white); }

.navbar {
  background: var(--color-primary);
  position: sticky;
  top: 0;
  z-index: 100;
}
.navbar .btn-accent:hover { background: #d48c1f; }

.nav-inner {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0 var(--space-md);
  min-height: 60px;
}

.logo {
  display: flex;
  flex-direction: column;
  line-height: 1.3;
  margin-right: auto;
}
.logo-zh {
  font-size: 20px;
  font-weight: 800;
  color: var(--color-accent);
}
.logo-en {
  font-size: 11px;
  letter-spacing: 1px;
  color: rgba(255,255,255,0.7);
  text-transform: uppercase;
}

/* ———— Navigation Menu ——— */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 0;
}
.nav-menu > li { position: relative; }
.nav-menu > li > a {
  display: block;
  padding: 20px 14px;
  color: rgba(255,255,255,0.85);
  font-size: 15px;
  font-weight: 500;
  white-space: nowrap;
  transition: color 0.2s;
}
.nav-menu > li > a:hover,
.nav-menu > li > a.active {
  color: var(--color-accent);
}

/* 桌面悬停下拉 */
.sub-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  background: var(--color-white);
  box-shadow: 0 8px 24px rgba(0,0,0,0.1);
  border-radius: var(--radius-sm);
  min-width: 160px;
  padding: 8px 0;
  z-index: 200;
}
.has-sub:hover .sub-menu { display: block; }
.sub-menu li a {
  display: block;
  padding: 10px 20px;
  color: var(--color-text);
  font-size: 14px;
}
.sub-menu li a:hover { background: var(--color-bg); color: var(--color-accent); }

.nav-cta {
  display: inline-block;
  background: var(--color-accent);
  color: var(--color-white) !important;
  padding: 10px 24px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 14px;
}
.nav-cta:hover { background: #d48c1f; }

.hamburger {
  display: none;
  background: none;
  border: none;
  font-size: 26px;
  color: var(--color-white);
  cursor: pointer;
  padding: 4px;
}

/* ===================== Hero ==================== */
.hero {
  position: relative;
  background: url('https://images.unsplash.com/photo-1494412574643-ff11b0a5c1c3?auto=format&fit=crop&w=1920&q=80') center/cover no-repeat;
  min-height: 600px;
  display: flex;
  align-items: center;
}
.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(15,43,70,0.85) 0%, rgba(10,31,51,0.7) 100%);
}
.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  color: var(--color-white);
  padding: var(--space-xl) 0;
}
.hero-content h1 {
  font-size: var(--font-size-h1);
  font-weight: 800;
  margin-bottom: var(--space-md);
  text-shadow: 0 2px 8px rgba(0,0,0,0.3);
}
.hero-sub {
  font-size: 19px;
  max-width: 720px;
  margin: 0 auto var(--space-lg);
  line-height: 1.7;
  opacity: 0.92;
}
.hero-actions {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}
.hero-stats {
  display: flex;
  gap: var(--space-lg);
  justify-content: center;
  flex-wrap: wrap;
  margin-top: var(--space-md);
}
.stat-item {
  text-align: center;
}
.stat-num {
  display: block;
  font-size: 28px;
  font-weight: 800;
  color: var(--color-accent);
  line-height: 1.3;
}
.stat-item { font-size: 15px; opacity: 0.85; }

/* ===================== 品类卡片 ===================== */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--space-md);
}
.category-card {
  background: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  transition: transform 0.2s, shadow 0.2s;
  color: var(--color-text);
}
.category-card:hover { transform: translateY(-4px); box-shadow: 0 8px 24px rgba(0,0,0,0.12); }
.cat-img {
  height: 180px;
  background-size: cover;
  background-position: center;
}
.category-card h3 {
  padding: var(--space-sm) var(--space-md) 0;
  font-size: var(--font-size-h3);
  color: var(--color-primary);
}
.category-card p {
  padding: 4px var(--space-md);
  color: var(--color-text-muted);
  font-size: 14px;
}
.cat-tag {
  display: block;
  padding: 8px var(--space-md) var(--space-sm);
  color: var(--color-accent);
  font-size: 13px;
  font-weight: 600;
}

/* ===================== 为什么选我们 ===================== */
.why-us { background: var(--color-surface); }
.why-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-lg);
  margin-bottom: var(--space-lg);
}
.why-card { text-align: center; padding: var(--space-lg) var(--space-md); }
.why-icon { font-size: 48px; margin-bottom: var(--space-md); }
.why-card h3 { font-size: var(--font-size-h3); color: var(--color-primary); margin-bottom: var(--space-sm); }
.why-card p { color: var(--color-text-muted); font-size: 15px; }
.cta-banner-inline {
  text-align: center;
  padding: var(--space-md);
  background: var(--color-bg);
  border-radius: var(--radius-md);
}
.cta-banner-inline p { margin-bottom: var(--space-sm); font-weight: 600; }

/* ===================== 采购流程 ===================== */
.process-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-md);
  counter-reset: step-counter;
}
.step { text-align: center; padding: var(--space-md); }
.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--color-white);
  font-weight: 800;
  font-size: 18px;
  margin-bottom: var(--space-sm);
}
.step h3 { font-size: var(--font-size-h3); color: var(--color-primary); margin-bottom: 4px; }
.step p { color: var(--color-text-muted); font-size: 14px; }

/* ===================== 实力背书 ===================== */
.stats { background: var(--color-primary); color: var(--color-white); }
.stats .section-title { color: var(--color-white); }
.stats-grid {
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  flex-wrap: wrap;
  margin-bottom: var(--space-lg);
}
.stats-card { text-align: center; }
.stats-number {
  display: block;
  font-size: 40px;
  font-weight: 800;
  color: var(--color-accent);
}
.stats-label { font-size: 14px; opacity: 0.85; }
.cert-chips {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
}
.chip {
  background: rgba(255,255,255,0.12);
  padding: 6px 16px;
  border-radius: 999px;
  font-size: 13px;
}

/* ===================== 客户评价 ===================== */
.testimonial-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-md);
}
.testimonial-card {
  background: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  padding: var(--space-lg);
  border-left: 4px solid var(--color-accent);
}
.testimonial-card p { font-size: 15px; font-style: italic; color: var(--color-text); margin-bottom: var(--space-sm); }
.testimonial-card footer { font-size: 13px; color: var(--color-text-muted); }

/* ===================== FAQ ===================== */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
}
.faq-item {
  background: var(--color-surface);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-sm);
  box-shadow: var(--shadow-card);
  overflow: hidden;
}
.faq-item summary {
  padding: var(--space-md);
  font-weight: 600;
  cursor: pointer;
  color: var(--color-primary);
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; font-size: 20px; font-weight: 700; color: var(--color-accent); transition: transform 0.2s; }
.faq-item[open] summary::after { content: "−"; }
.faq-item p { padding: 0 var(--space-md) var(--space-md); color: var(--color-text-muted); font-size: 15px; }

/* ===================== 底部 CTA 横幅 ===================== */
.cta-banner {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: var(--color-white);
  padding: var(--space-xl) 0;
}
.cta-banner-inner h2 { text-align: center; font-size: var(--font-size-h2); margin-bottom: var(--space-sm); }
.cta-banner-inner > p { text-align: center; opacity: 0.85; margin-bottom: var(--space-lg); }

.quick-form {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-sm);
  max-width: 640px;
  margin: 0 auto;
}
.quick-form textarea,
.quick-form select { grid-column: 1 / -1; }
.quick-form button { grid-column: 1 / -1; }

.quick-form input,
.quick-form textarea,
.quick-form select {
  padding: 12px 14px;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 15px;
  background: var(--color-white);
  color: var(--color-text);
}
.quick-form input:focus,
.quick-form textarea:focus,
.quick-form select:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: -2px;
}
.quick-form button { margin-top: var(--space-sm); }
.form-hint { text-align: center; font-size: 13px; opacity: 0.7; margin-top: var(--space-sm); }
.form-hint a { color: var(--color-accent); text-decoration: underline; }

/* ===================== 页脚 ===================== */
.site-footer {
  background: var(--color-primary-dark);
  color: rgba(255,255,255,0.7);
  padding: var(--space-xl) 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-lg);
}
.footer-col h4 { color: var(--color-white); margin-bottom: var(--space-md); font-size: 16px; }
.footer-col p { font-size: 14px; line-height: 1.7; }
.footer-col ul li { margin-bottom: 6px; }
.footer-col ul li a { color: rgba(255,255,255,0.65); font-size: 14px; }
.footer-col ul li a:hover { color: var(--color-accent); }

.footer-contact span {
  display: block;
  margin-top: var(--space-sm);
  font-size: 14px;
}

.footer-bottom {
  margin-top: var(--space-lg);
  border-top: 1px solid rgba(255,255,255,0.1);
  padding: var(--space-md) 0;
  text-align: center;
  font-size: 13px;
}

/* ===================== 响应式 ===================== */
@media (max-width: 768px) {
  .hamburger { display: block; }

  .nav-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-primary-dark);
    flex-direction: column;
    padding: var(--space-sm) 0;
    z-index: 300;
    box-shadow: 0 8px 24px rgba(0,0,0,0.2);
  }
  .nav-menu.open { display: flex; }
  .nav-menu > li > a { padding: 14px var(--space-md); }

  .sub-menu {
    display: none;
    position: static;
    background: rgba(255,255,255,0.08);
    box-shadow: none;
    padding-left: var(--space-md);
  }
  .has-sub.sub-open .sub-menu { display: block; }
  .sub-menu li a { color: rgba(255,255,255,0.7); padding: 10px 16px; }

  .nav-cta { display: none; }

  .hero { min-height: auto; }
  .hero-content { padding: var(--space-lg) 0; }

  .footer-grid { grid-template-columns: 1fr 1fr; }
  .quick-form { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  .hero-stats { gap: var(--space-sm); }
  .stat-item { min-width: 80px; }
  .footer-grid { grid-template-columns: 1fr; }
  .process-steps { grid-template-columns: 1fr; }
}