/* ============================================================
   brevo-site — 外贸企业官网样式表
   Pure CSS, responsive, professional foreign trade style
   ============================================================ */

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

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

body {
  font-family: 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
  color: #333;
  background: #fff;
  line-height: 1.7;
}

/* --- Colors --- */
:root {
  --primary: #1B2A4A;
  --primary-light: #2B4C7E;
  --accent: #3B82C4;
  --accent-light: #E8F0FE;
  --gray-100: #F8F9FA;
  --gray-200: #E9ECEF;
  --gray-500: #6C757D;
  --gray-700: #495057;
  --text: #333;
  --white: #fff;
  --border-radius: 8px;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
  --shadow-hover: 0 6px 24px rgba(0,0,0,0.12);
  --max-width: 1200px;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s;
}
a:hover {
  color: var(--primary-light);
}

img {
  max-width: 100%;
  height: auto;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* --- Header / Navigation --- */
header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--white);
  box-shadow: 0 1px 4px rgba(0,0,0,0.08);
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 68px;
}

.logo a {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: -0.3px;
}
.logo a:hover {
  color: var(--primary);
}

nav {
  display: flex;
  align-items: center;
}

nav a {
  margin-left: 28px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--gray-700);
  padding: 4px 0;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
}

nav a:hover,
nav a.active {
  color: var(--primary);
  border-bottom-color: var(--accent);
}

/* Hamburger (hidden on desktop) */
.hamburger {
  display: none;
  flex-direction: column;
  cursor: pointer;
  gap: 5px;
  padding: 4px;
  background: none;
  border: none;
}
.hamburger span {
  display: block;
  width: 26px;
  height: 3px;
  background: var(--primary);
  border-radius: 2px;
  transition: 0.3s;
}

/* --- Hero --- */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  color: var(--white);
  padding: 100px 0 80px;
  text-align: center;
}

.hero h1 {
  font-size: 2.8rem;
  font-weight: 700;
  margin-bottom: 20px;
  line-height: 1.2;
}

.hero p {
  font-size: 1.2rem;
  max-width: 700px;
  margin: 0 auto 32px;
  opacity: 0.9;
  line-height: 1.6;
}

.btn {
  display: inline-block;
  padding: 14px 36px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: 6px;
  border: none;
  cursor: pointer;
  transition: all 0.25s;
  text-align: center;
}

.btn-primary {
  background: var(--accent);
  color: var(--white);
}
.btn-primary:hover {
  background: #2a6fa8;
  color: var(--white);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(59,130,196,0.35);
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border: 2px solid var(--accent);
}
.btn-outline:hover {
  background: var(--accent);
  color: var(--white);
}

/* --- Sections --- */
section {
  padding: 72px 0;
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary);
  text-align: center;
  margin-bottom: 12px;
}

.section-subtitle {
  text-align: center;
  color: var(--gray-500);
  font-size: 1.05rem;
  margin-bottom: 48px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* --- About Intro (index) --- */
.about-intro {
  background: var(--white);
}

.about-intro .content {
  max-width: 800px;
  margin: 0 auto;
  font-size: 1.05rem;
  text-align: center;
  color: var(--gray-700);
}

.about-intro .content p {
  margin-bottom: 16px;
}

/* --- Advantages Grid --- */
.advantages {
  background: var(--gray-100);
}

.advantages-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px;
}

.advantage-card {
  background: var(--white);
  border-radius: var(--border-radius);
  padding: 36px 24px;
  text-align: center;
  box-shadow: var(--shadow);
  transition: all 0.3s;
}

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

.advantage-card .icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
  color: var(--accent);
}

.advantage-card h3 {
  font-size: 1.1rem;
  color: var(--primary);
  margin-bottom: 10px;
}

.advantage-card p {
  font-size: 0.92rem;
  color: var(--gray-500);
  line-height: 1.6;
}

/* --- Product Preview / Grid --- */
.product-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px;
}

.product-card {
  background: var(--white);
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: all 0.3s;
}

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

.product-placeholder {
  width: 100%;
  aspect-ratio: 4 / 3;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--white);
  text-align: center;
  padding: 16px;
}

.product-placeholder.p1 { background: linear-gradient(135deg, #3B82C4, #1B2A4A); }
.product-placeholder.p2 { background: linear-gradient(135deg, #2B6CB0, #1a3a5c); }
.product-placeholder.p3 { background: linear-gradient(135deg, #4A90D9, #2B4C7E); }
.product-placeholder.p4 { background: linear-gradient(135deg, #5A9FD4, #1B2A4A); }
.product-placeholder.p5 { background: linear-gradient(135deg, #3a7abd, #243b5e); }
.product-placeholder.p6 { background: linear-gradient(135deg, #6Aafe0, #2B4C7E); }

.product-card h3 {
  font-size: 1rem;
  color: var(--primary);
  padding: 16px 16px 6px;
}

.product-card p {
  font-size: 0.88rem;
  color: var(--gray-500);
  padding: 0 16px 16px;
  line-height: 1.5;
}

/* --- Page Header (inner pages) --- */
.page-header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  color: var(--white);
  padding: 60px 0;
  text-align: center;
}

.page-header h1 {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.page-header p {
  font-size: 1.05rem;
  opacity: 0.85;
}

/* --- Content Sections (about, privacy) --- */
.content-section {
  padding: 60px 0;
}

.content-section .content {
  max-width: 860px;
  margin: 0 auto;
}

.content-section h2 {
  font-size: 1.6rem;
  color: var(--primary);
  margin-top: 40px;
  margin-bottom: 16px;
}

.content-section h2:first-child {
  margin-top: 0;
}

.content-section h3 {
  font-size: 1.2rem;
  color: var(--primary-light);
  margin-top: 28px;
  margin-bottom: 10px;
}

.content-section p {
  margin-bottom: 16px;
  color: var(--gray-700);
  font-size: 1rem;
  line-height: 1.8;
}

.content-section ul {
  margin: 12px 0 20px 24px;
  list-style: disc;
}

.content-section ul li {
  margin-bottom: 8px;
  color: var(--gray-700);
  font-size: 1rem;
  line-height: 1.7;
}

/* --- Values / About --- */
.values-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-top: 24px;
}

.value-item {
  background: var(--gray-100);
  padding: 24px;
  border-radius: var(--border-radius);
  border-left: 4px solid var(--accent);
}

.value-item h3 {
  margin-top: 0;
  margin-bottom: 8px;
  font-size: 1.05rem;
  color: var(--primary);
}

.value-item p {
  margin-bottom: 0;
  font-size: 0.92rem;
}

/* --- Contact Page --- */
.contact-info-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin-bottom: 48px;
}

.contact-info-item {
  background: var(--gray-100);
  border-radius: var(--border-radius);
  padding: 32px 24px;
  text-align: center;
  border: 1px solid var(--gray-200);
}

.contact-info-item .icon {
  font-size: 2rem;
  margin-bottom: 12px;
  color: var(--accent);
}

.contact-info-item h3 {
  font-size: 0.95rem;
  color: var(--primary);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.contact-info-item p {
  font-size: 0.95rem;
  color: var(--gray-700);
}

.contact-info-item a {
  color: var(--accent);
  font-weight: 500;
}

.contact-form-wrapper {
  max-width: 640px;
  margin: 0 auto;
}

.contact-form-wrapper h2 {
  text-align: center;
  margin-bottom: 8px;
}

.contact-form-wrapper > p {
  text-align: center;
  color: var(--gray-500);
  margin-bottom: 32px;
}

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

.form-group label {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: 6px;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  font-size: 0.95rem;
  border: 1px solid var(--gray-200);
  border-radius: 6px;
  transition: border-color 0.2s;
  font-family: inherit;
  background: var(--white);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(59,130,196,0.12);
}

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

/* --- Footer --- */
footer {
  background: var(--primary);
  color: rgba(255,255,255,0.85);
  padding: 48px 0 32px;
}

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

footer h4 {
  color: var(--white);
  font-size: 1.05rem;
  margin-bottom: 16px;
}

footer p, footer a {
  font-size: 0.9rem;
  color: rgba(255,255,255,0.7);
  line-height: 1.8;
}

footer a:hover {
  color: var(--white);
}

footer .copyright {
  grid-column: 1 / -1;
  border-top: 1px solid rgba(255,255,255,0.15);
  padding-top: 24px;
  margin-top: 16px;
  text-align: center;
  font-size: 0.85rem;
  color: rgba(255,255,255,0.55);
}

footer .copyright a {
  color: rgba(255,255,255,0.65);
  font-size: 0.85rem;
}

/* --- Products page --- */
.product-detail-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .hamburger {
    display: flex;
  }

  nav {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: var(--white);
    flex-direction: column;
    padding: 16px 20px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  }

  nav.open {
    display: flex;
  }

  nav a {
    margin-left: 0;
    padding: 12px 0;
    border-bottom: 1px solid var(--gray-200);
    width: 100%;
  }

  nav a:last-child {
    border-bottom: none;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .advantages-grid,
  .product-grid,
  .product-detail-grid,
  .contact-info-grid {
    grid-template-columns: 1fr;
  }

  footer .container {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .values-list {
    grid-template-columns: 1fr;
  }

  section {
    padding: 48px 0;
  }

  .section-title {
    font-size: 1.6rem;
  }
}

@media (max-width: 480px) {
  .hero {
    padding: 60px 0 48px;
  }

  .hero h1 {
    font-size: 1.6rem;
  }

  .btn {
    padding: 12px 28px;
    font-size: 0.9rem;
  }
}