/* ===================================================
   landing.css — Bag In Box Landing Page Styles
   结构说明：
   1. CSS Variables & Reset
   2. Typography & Base
   3. Layout Helpers
   4. Components (buttons, titles, placeholders)
   5. Sections (banner, intro, application, products,
      about, advantage, cert, news, knowledge, contact)
   6. Responsive
   =================================================== */


/* ───────────────────────────────────────────
   1. CSS Variables & Reset
─────────────────────────────────────────── */
:root {
  --c-primary:    #e8a020;   /* 主色 — 琥珀金 */
  --c-primary-dk: #c4841a;
  --c-dark:       #0f1c28;   /* 深色背景 */
  --c-dark-2:     #1a2a3a;
  --c-dark-3:     #243344;
  --c-light:      #f5f7fa;
  --c-white:      #ffffff;
  --c-text:       #333d4b;
  --c-text-muted: #6b7a8d;
  --c-border:     #dde3ec;
  --c-card-bg:    #ffffff;

  --font-head:  'Georgia', 'Times New Roman', serif;
  --font-body:  'Segoe UI', 'Helvetica Neue', Arial, sans-serif;

  --radius:    8px;
  --shadow-sm: 0 2px 12px rgba(0,0,0,.07);
  --shadow-md: 0 6px 28px rgba(0,0,0,.12);
  --shadow-lg: 0 16px 60px rgba(0,0,0,.18);

  --transition: 0.28s ease;
  --max-w: 1200px;
  --pad-section: 80px 0;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.75;
  color: var(--c-text);
  background: var(--c-white);
}

img { max-width: 100%; display: block; }
a  { text-decoration: none; color: inherit; }
ul { list-style: none; }


/* ───────────────────────────────────────────
   2. Typography
─────────────────────────────────────────── */
h1, h2, h3, h4, h5 {
  font-family: var(--font-head);
  line-height: 1.25;
  color: var(--c-dark);
}
h1 { font-size: clamp(2rem, 4vw, 3rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2.2rem); }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.05rem; }

p { margin-bottom: 1em; color: var(--c-text); }
p:last-child { margin-bottom: 0; }

strong { font-weight: 700; }


/* ───────────────────────────────────────────
   3. Layout Helpers
─────────────────────────────────────────── */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

.section-padding { padding: var(--pad-section); }

.bg-light { background: var(--c-light); }
.bg-dark  { background: var(--c-dark);  }

/* Two-column grid */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.two-col.reverse { direction: rtl; }
.two-col.reverse > * { direction: ltr; }


/* ───────────────────────────────────────────
   4. Components
─────────────────────────────────────────── */

/* --- Section Title --- */
.section-title {
  margin-bottom: 48px;
}
.section-title.centered { text-align: center; }
.section-title.left-aligned { text-align: left; }

.section-title h2 { margin-bottom: 12px; }
.section-title .label {
  font-size: 12px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--c-primary);
  font-weight: 600;
  margin-bottom: 8px;
}
.section-title .subtitle {
  font-size: 13px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--c-text-muted);
  margin-top: 8px;
}
.section-title.light h2,
.section-title.light p { color: var(--c-white); }

.title-line {
  display: block;
  width: 48px;
  height: 3px;
  background: var(--c-primary);
  border-radius: 2px;
  margin-top: 16px;
}
.section-title.centered .title-line {
  margin-left: auto;
  margin-right: auto;
}

/* --- Buttons --- */
.btn-primary {
  display: inline-block;
  padding: 13px 32px;
  background: var(--c-primary);
  color: var(--c-dark);
  font-weight: 700;
  font-size: 13px;
  letter-spacing: 1px;
  text-transform: uppercase;
  border-radius: var(--radius);
  border: 2px solid var(--c-primary);
  transition: background var(--transition), color var(--transition), transform var(--transition);
  margin-top: 20px;
  cursor: pointer;
}
.btn-primary:hover {
  background: var(--c-primary-dk);
  border-color: var(--c-primary-dk);
  transform: translateY(-2px);
}
.btn-primary.outline {
  background: transparent;
  color: var(--c-primary);
  border-color: var(--c-primary);
}
.btn-primary.outline:hover {
  background: var(--c-primary);
  color: var(--c-dark);
}

.btn-more {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--c-primary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  transition: gap var(--transition), color var(--transition);
}
.btn-more:hover { gap: 10px; color: var(--c-primary-dk); }

/* --- Image Placeholders (replace with real <img> tags) --- */
.img-placeholder {
  width: 100%;
  aspect-ratio: 4/3;
  background: linear-gradient(135deg, #e8edf3 0%, #d1d9e4 100%);
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  color: #9aabb8;
  font-size: 13px;
}
.img-placeholder i { font-size: 40px; }
.img-placeholder.wide { aspect-ratio: 16/5; }
.img-placeholder.small { aspect-ratio: 3/2; }
.img-placeholder.dark {
  background: linear-gradient(135deg, #1a2a3a 0%, #243344 100%);
  color: #5a7a96;
}
.img-placeholder.cert { aspect-ratio: 4/3; }


/* ───────────────────────────────────────────
   5a. Inner Banner
─────────────────────────────────────────── */
.inner-banner {
  position: relative;
  height: 280px;
  background: linear-gradient(135deg, var(--c-dark) 0%, var(--c-dark-3) 60%, #1e3a50 100%);
  display: flex;
  align-items: center;
  overflow: hidden;
}
.inner-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 80% 50%, rgba(232,160,32,.15) 0%, transparent 60%),
    url("data:image/svg+xml,%3Csvg width='60' height='60' xmlns='http://www.w3.org/2000/svg'%3E%3Crect width='60' height='60' fill='none'/%3E%3Crect x='0' y='0' width='1' height='1' fill='rgba(255,255,255,.04)'/%3E%3C/svg%3E");
}
.banner-content {
  position: relative;
  z-index: 2;
  padding: 0 40px;
}
.banner-content h1 {
  color: var(--c-white);
  font-size: clamp(2rem, 5vw, 3rem);
  letter-spacing: 1px;
}
.breadcrumb {
  margin-top: 10px;
  font-size: 13px;
  color: rgba(255,255,255,.6);
}
.breadcrumb a { color: rgba(255,255,255,.6); transition: color var(--transition); }
.breadcrumb a:hover { color: var(--c-primary); }
.breadcrumb span { margin: 0 8px; }
.breadcrumb em { color: var(--c-primary); font-style: normal; }


/* ───────────────────────────────────────────
   5b. Product Intro
─────────────────────────────────────────── */
.product-intro .col-text p {
  color: var(--c-text-muted);
  line-height: 1.9;
  margin-bottom: 14px;
  font-size: 16px;
}


/* ───────────────────────────────────────────
   5c. Application Industry
─────────────────────────────────────────── */
.app-banner { margin-bottom: 40px; }

.app-grid {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  gap: 16px;
}
.app-item {
  background: var(--c-white);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 24px 12px 16px;
  text-align: center;
  transition: box-shadow var(--transition), transform var(--transition), border-color var(--transition);
}
.app-item:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
  border-color: var(--c-primary);
}
.app-icon {
  font-size: 28px;
  color: var(--c-primary);
  margin-bottom: 10px;
}
.app-name {
  font-size: 12px;
  font-weight: 600;
  color: var(--c-text);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}


/* ───────────────────────────────────────────
   5d. Product List
─────────────────────────────────────────── */
.product-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}
.product-card {
  background: var(--c-card-bg);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition);
  display: flex;
  flex-direction: column;
}
.product-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-6px);
}
.card-img { display: block; overflow: hidden; }
.card-img .img-placeholder {
  border-radius: 0;
  transition: transform 0.4s ease;
}
.product-card:hover .card-img .img-placeholder { transform: scale(1.03); }

.card-body {
  padding: 20px 22px 22px;
  flex: 1;
  display: flex;
  flex-direction: column;
}
.card-cat {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--c-primary);
  font-weight: 600;
  margin-bottom: 6px;
}
.card-body h4 {
  margin-bottom: 10px;
  line-height: 1.4;
}
.card-body h4 a { color: var(--c-dark); transition: color var(--transition); }
.card-body h4 a:hover { color: var(--c-primary); }
.card-desc {
  font-size: 13px;
  color: var(--c-text-muted);
  flex: 1;
  margin-bottom: 16px;
}


/* ───────────────────────────────────────────
   5e. About Section
─────────────────────────────────────────── */
.about-section {
  background: linear-gradient(135deg, var(--c-dark) 0%, var(--c-dark-3) 100%);
}
.about-section p {
  color: rgba(255,255,255,.7);
  line-height: 1.9;
  font-size: 15px;
}
.about-section h2 { color: var(--c-white); }


/* ───────────────────────────────────────────
   5f. Advantage Stats
─────────────────────────────────────────── */
.advantage {
  background: var(--c-white);
  border-top: 1px solid var(--c-border);
  border-bottom: 1px solid var(--c-border);
}
.stats-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 0;
}
.stat-item {
  text-align: center;
  padding: 40px 20px;
  border-right: 1px solid var(--c-border);
  transition: background var(--transition);
}
.stat-item:last-child { border-right: none; }
.stat-item:hover { background: var(--c-light); }

.stat-icon {
  font-size: 28px;
  color: var(--c-primary);
  margin-bottom: 14px;
}
.stat-num {
  font-family: var(--font-head);
  font-size: clamp(2rem, 3.5vw, 2.8rem);
  font-weight: 700;
  color: var(--c-dark);
  line-height: 1;
  margin-bottom: 8px;
}
.stat-label {
  font-size: 12px;
  color: var(--c-text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
}


/* ───────────────────────────────────────────
   5g. Certification
─────────────────────────────────────────── */
.cert-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}


/* ───────────────────────────────────────────
   5h. News
─────────────────────────────────────────── */
.news-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}
.news-card {
  background: var(--c-white);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition);
  display: flex;
  flex-direction: column;
}
.news-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}
.news-date {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--c-primary);
  font-size: 13px;
  margin-bottom: 16px;
}
.news-card h4 {
  margin-bottom: 12px;
  line-height: 1.5;
}
.news-card h4 a { color: var(--c-dark); transition: color var(--transition); }
.news-card h4 a:hover { color: var(--c-primary); }
.news-card p {
  font-size: 13px;
  color: var(--c-text-muted);
  flex: 1;
  margin-bottom: 20px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}


/* ───────────────────────────────────────────
   5i. Industry Knowledge
─────────────────────────────────────────── */
.knowledge-section .knowledge-title {
  margin-bottom: 40px;
  position: relative;
  padding-bottom: 16px;
}
.knowledge-section .knowledge-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 48px;
  height: 3px;
  background: var(--c-primary);
  border-radius: 2px;
}
.knowledge-section h3 {
  color: var(--c-dark);
  margin-bottom: 16px;
}
.knowledge-section p {
  color: var(--c-text-muted);
  line-height: 1.9;
  font-size: 15px;
}


/* ───────────────────────────────────────────
   5j. Contact Form
─────────────────────────────────────────── */
.contact-section {
  background: linear-gradient(135deg, var(--c-dark) 0%, var(--c-dark-2) 100%);
}
.contact-section .section-title.light .subtitle {
  color: rgba(255,255,255,.55);
}
.contact-form { max-width: 860px; margin: 0 auto; }
.form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
.form-grid input,
.form-grid textarea {
  width: 100%;
  padding: 14px 18px;
  background: rgba(255,255,255,.07);
  border: 1px solid rgba(255,255,255,.15);
  border-radius: var(--radius);
  color: var(--c-white);
  font-size: 13px;
  letter-spacing: 0.5px;
  outline: none;
  transition: border-color var(--transition), background var(--transition);
  font-family: var(--font-body);
}
.form-grid input::placeholder,
.form-grid textarea::placeholder {
  color: rgba(255,255,255,.35);
}
.form-grid input:focus,
.form-grid textarea:focus {
  border-color: var(--c-primary);
  background: rgba(255,255,255,.10);
}
.form-grid .full-width { grid-column: 1 / -1; }
.form-grid .submit-btn {
  grid-column: 1 / -1;
  border: none;
  padding: 16px;
  font-size: 14px;
  letter-spacing: 2px;
  margin-top: 4px;
  width: 100%;
  cursor: pointer;
}


/* ───────────────────────────────────────────
   6. Responsive
─────────────────────────────────────────── */

/* Tablet: ≤ 1024px */
@media (max-width: 1024px) {
  :root { --pad-section: 60px 0; }

  .app-grid {
    grid-template-columns: repeat(4, 1fr);
  }
  .product-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .stats-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .stat-item:nth-child(3) { border-right: none; }
  .stat-item:nth-child(4) { border-right: 1px solid var(--c-border); }
}

/* Mobile: ≤ 768px */
@media (max-width: 768px) {
  :root { --pad-section: 48px 0; }

  .two-col,
  .two-col.reverse {
    grid-template-columns: 1fr;
    direction: ltr;
    gap: 32px;
  }

  .app-grid { grid-template-columns: repeat(4, 1fr); gap: 10px; }
  .app-item { padding: 16px 8px 12px; }
  .app-icon { font-size: 22px; }

  .product-grid { grid-template-columns: 1fr 1fr; gap: 16px; }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .stat-item { border-right: none; border-bottom: 1px solid var(--c-border); }
  .stat-item:last-child { border-bottom: none; grid-column: 1 / -1; }

  .cert-grid { grid-template-columns: 1fr; }
  .news-grid  { grid-template-columns: 1fr; }

  .form-grid { grid-template-columns: 1fr; }
  .form-grid .full-width { grid-column: 1; }
  .form-grid .submit-btn { grid-column: 1; }

  .inner-banner { height: 180px; }
  .banner-content { padding: 0 20px; }
}

/* Small Mobile: ≤ 480px */
@media (max-width: 480px) {
  .app-grid { grid-template-columns: repeat(2, 1fr); }
  .product-grid { grid-template-columns: 1fr; }
}
a.btnForm {
    display: inline-block;
    background: #0d56b4;
    font-size: 14px;
    font-family: Roboto;
    font-weight: 500;
    color: #FFFFFF;
    line-height: 1;
    padding: 15px 44px;
    text-transform: uppercase;
}
/* ───────────────────────────────────────────
   AVAILABLE SIZES SECTION
─────────────────────────────────────────── */
.sizes-section {
  background: var(--c-white);
}

.sizes-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 20px;
  margin-bottom: 48px;
}

/* --- Size Card Base --- */
.size-card {
  background: var(--c-white);
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius);
  padding: 28px 20px 24px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  transition: box-shadow var(--transition), transform var(--transition), border-color var(--transition);
}
.size-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-5px);
  border-color: var(--c-primary);
}

/* --- Featured Cards (10L & 20L) --- */
.size-card--featured {
  border: 2px solid var(--c-primary);
  background: #fffbf2;
  position: relative;
}
.size-card--featured::before {
  content: '★ Popular';
  position: absolute;
  top: -13px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--c-primary);
  color: var(--c-dark);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  padding: 3px 14px;
  border-radius: 20px;
  white-space: nowrap;
}

/* --- Custom Card --- */
.size-card--custom {
  background: var(--c-light);
  border-style: dashed;
}

/* --- Size Badge --- */
.size-badge {
  display: inline-block;
  font-size: 18px;
  font-weight: 700;
  font-family: var(--font-head);
  color: var(--c-dark);
  margin-bottom: 4px;
}
.size-badge.featured {
  color: var(--c-primary);
  font-size: 20px;
}
.size-badge.custom {
  color: var(--c-text-muted);
}

/* --- Size Icon --- */
.size-icon {
  font-size: 32px;
  color: var(--c-primary);
  margin: 4px 0;
}
.size-card--custom .size-icon {
  color: var(--c-text-muted);
}

/* --- Size Card Heading --- */
.size-card h4 {
  font-size: 14px;
  font-weight: 700;
  color: var(--c-dark);
  margin: 0;
}

/* --- Size Card Description --- */
.size-card p {
  font-size: 13px;
  color: var(--c-text-muted);
  line-height: 1.7;
  margin: 0;
}

/* --- Tags --- */
.size-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  justify-content: center;
  margin-top: 8px;
}
.size-tags li {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--c-primary-dk);
  background: rgba(232, 160, 32, 0.1);
  border: 1px solid rgba(232, 160, 32, 0.25);
  border-radius: 20px;
  padding: 3px 10px;
}

/* --- CTA Row --- */
.sizes-cta {
  text-align: center;
  padding-top: 16px;
  border-top: 1px solid var(--c-border);
}
.sizes-cta p {
  font-size: 15px;
  color: var(--c-text-muted);
  margin-bottom: 20px;
}
.sizes-cta p strong {
  color: var(--c-dark);
}

/* ── Responsive ── */
@media (max-width: 1200px) {
  .sizes-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .sizes-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 14px;
  }
  .size-card {
    padding: 22px 14px 18px;
  }
}

@media (max-width: 480px) {
  .sizes-grid {
    grid-template-columns: 1fr;
  }
}