:root {
  --ink: #101820;
  --ink-soft: #233241;
  --steel: #6e7d8a;
  --line: #d9e0e7;
  --paper: #f5f7fa;
  --white: #ffffff;
  --blue: #0b5cab;
  --blue-deep: #083d73;
  --gold: #d8a13a;
  --danger: #b22b2b;
  --shadow: 0 18px 44px rgba(16, 24, 32, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.65;
}

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

a {
  color: inherit;
  text-decoration: none;
}

button,
input,
textarea,
select {
  font: inherit;
}

:focus-visible {
  outline: 3px solid rgba(216, 161, 58, 0.65);
  outline-offset: 3px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(16, 24, 32, 0.96);
  color: var(--white);
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.top-strip {
  background: #07111b;
  color: #c6d3df;
  font-size: 13px;
}

.top-strip .container {
  min-height: 34px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.container {
  width: min(1160px, calc(100% - 40px));
  margin: 0 auto;
}

.nav-row {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.brand-mark {
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.28);
  background: linear-gradient(135deg, #123a5f, #0b5cab);
  color: var(--white);
  font-weight: 800;
  letter-spacing: 0;
}

.brand-title {
  display: block;
  font-size: 18px;
  font-weight: 800;
  line-height: 1.25;
}

.brand-title-short {
  display: none;
}

.brand-subtitle {
  display: block;
  color: #aebdca;
  font-size: 12px;
  margin-top: 2px;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 6px;
}

.main-nav a {
  padding: 10px 14px;
  color: #d8e2ea;
  font-size: 15px;
}

.main-nav a:hover,
.main-nav a.active {
  color: var(--white);
  background: rgba(255, 255, 255, 0.09);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  white-space: nowrap;
}

.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid rgba(255, 255, 255, 0.24);
  background: transparent;
  color: var(--white);
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  margin: 4px auto;
  background: currentColor;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 18px;
  border: 1px solid transparent;
  border-radius: 4px;
  font-weight: 700;
  cursor: pointer;
}

.btn-primary {
  color: var(--white);
  background: var(--danger);
}

.btn-primary:hover {
  background: #921f1f;
}

.btn-secondary {
  color: var(--white);
  background: var(--blue);
}

.btn-secondary:hover {
  background: var(--blue-deep);
}

.btn-ghost {
  color: var(--white);
  border-color: rgba(255, 255, 255, 0.36);
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.1);
}

.hero {
  color: var(--white);
  background:
    linear-gradient(90deg, rgba(8, 19, 30, 0.96), rgba(8, 19, 30, 0.74) 48%, rgba(8, 19, 30, 0.34)),
    url("../img/product-main-die.png") right center / contain no-repeat,
    #101820;
}

.hero .container {
  min-height: 590px;
  display: grid;
  grid-template-columns: minmax(0, 680px) 1fr;
  align-items: center;
  gap: 40px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 18px;
  color: #e9bf69;
  font-size: 14px;
  font-weight: 700;
}

.eyebrow::before {
  content: "";
  width: 34px;
  height: 2px;
  background: var(--gold);
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 20px;
  font-size: clamp(38px, 5vw, 64px);
  line-height: 1.08;
  letter-spacing: 0;
}

.hero-copy {
  max-width: 640px;
  margin-bottom: 28px;
  color: #d8e2ea;
  font-size: 18px;
}

.hero-actions,
.section-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin-top: 42px;
  max-width: 680px;
}

.metric {
  padding: 16px;
  border-left: 3px solid var(--gold);
  background: rgba(255, 255, 255, 0.08);
}

.metric strong {
  display: block;
  font-size: 22px;
}

.metric span {
  color: #c6d3df;
  font-size: 13px;
}

.section {
  padding: 76px 0;
}

.section-white {
  background: var(--white);
}

.section-dark {
  color: var(--white);
  background: var(--ink);
}

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 28px;
  margin-bottom: 30px;
}

.section-head h2 {
  margin-bottom: 8px;
  font-size: clamp(28px, 3.3vw, 42px);
  line-height: 1.2;
}

.section-head p {
  max-width: 660px;
  color: var(--steel);
}

.section-dark .section-head p {
  color: #bfccd8;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
}

.feature,
.product-card,
.contact-panel,
.info-panel {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.feature {
  padding: 24px;
}

.feature h3 {
  margin-bottom: 8px;
  font-size: 20px;
}

.feature p {
  color: var(--steel);
}

.feature-number {
  display: inline-grid;
  place-items: center;
  width: 36px;
  height: 36px;
  margin-bottom: 18px;
  color: var(--white);
  background: var(--blue);
  font-weight: 800;
}

.product-card {
  overflow: hidden;
  box-shadow: 0 8px 22px rgba(16, 24, 32, 0.06);
}

.product-card img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: contain;
  padding: 16px;
  background: #eef3f7;
}

.product-card-body {
  padding: 18px;
}

.product-card h3 {
  margin-bottom: 7px;
  font-size: 18px;
}

.product-card p {
  min-height: 52px;
  color: var(--steel);
  font-size: 14px;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}

.tag {
  padding: 5px 9px;
  color: var(--blue-deep);
  background: #e8f1fa;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 700;
}

.cta-band {
  padding: 44px;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 28px;
  color: var(--white);
  background:
    linear-gradient(100deg, rgba(8, 61, 115, 0.96), rgba(11, 92, 171, 0.88)),
    url("../img/product-cold-heading.jpg") right center / auto 120% no-repeat;
  border-radius: 8px;
}

.cta-band h2 {
  margin-bottom: 8px;
  font-size: clamp(24px, 3vw, 36px);
}

.cta-band p {
  margin-bottom: 0;
  color: #e1edf7;
}

.page-hero {
  padding: 72px 0;
  color: var(--white);
  background:
    linear-gradient(90deg, rgba(16, 24, 32, 0.94), rgba(16, 24, 32, 0.72)),
    url("../img/product-pin-thread-plate.jpg") right center / contain no-repeat,
    var(--ink);
}

.page-hero h1 {
  max-width: 760px;
}

.page-hero p {
  max-width: 760px;
  color: #d8e2ea;
  font-size: 18px;
}

.about-layout,
.contact-layout {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 30px;
  align-items: start;
}

.info-panel {
  padding: 30px;
}

.info-panel img {
  width: 100%;
  max-height: 310px;
  object-fit: cover;
  margin-bottom: 22px;
  border-radius: 6px;
}

.check-list {
  display: grid;
  gap: 12px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.check-list li {
  position: relative;
  padding-left: 26px;
}

.check-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 10px;
  height: 10px;
  background: var(--gold);
}

.category-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.category {
  padding: 24px;
  border: 1px solid var(--line);
  background: var(--white);
  border-radius: 8px;
}

.category h2 {
  margin-bottom: 10px;
  font-size: 23px;
}

.category p {
  color: var(--steel);
}

.contact-panel {
  padding: 28px;
}

.contact-list {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.contact-list a {
  color: var(--blue-deep);
  font-weight: 800;
}

.qr-box {
  display: grid;
  grid-template-columns: 112px 1fr;
  gap: 18px;
  align-items: center;
  margin-top: 22px;
  padding: 16px;
  background: #eef3f7;
  border-radius: 8px;
}

.qr-box img {
  width: 112px;
  height: 112px;
  object-fit: cover;
  background: var(--white);
}

.inquiry-form {
  display: grid;
  gap: 14px;
}

.field-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

label {
  display: grid;
  gap: 6px;
  color: var(--ink-soft);
  font-weight: 700;
}

input,
select,
textarea {
  width: 100%;
  min-height: 46px;
  padding: 10px 12px;
  border: 1px solid #c8d2dc;
  border-radius: 4px;
  background: var(--white);
}

textarea {
  min-height: 128px;
  resize: vertical;
}

.form-note {
  min-height: 24px;
  margin: 0;
  color: var(--blue-deep);
  font-weight: 700;
}

.form-note a {
  color: var(--danger);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.site-footer {
  padding: 42px 0 88px;
  color: #c6d3df;
  background: #07111b;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr 0.8fr;
  gap: 30px;
}

.site-footer h2,
.site-footer h3 {
  color: var(--white);
}

.footer-links {
  display: grid;
  gap: 8px;
}

.mobile-contact-bar {
  display: none;
}

@media (max-width: 980px) {
  .container {
    width: min(100% - 28px, 1160px);
  }

  .menu-toggle {
    display: inline-block;
  }

  .main-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 10px 14px 18px;
    background: #101820;
    border-top: 1px solid rgba(255, 255, 255, 0.12);
  }

  .main-nav.open {
    display: flex;
  }

  .header-actions {
    display: none;
  }

  .hero .container {
    min-height: 600px;
    grid-template-columns: 1fr;
  }

  .grid-4,
  .grid-3,
  .about-layout,
  .contact-layout,
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .cta-band {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 680px) {
  body {
    padding-bottom: 72px;
  }

  .top-strip {
    display: none;
  }

  .nav-row {
    min-height: 66px;
  }

  .brand-title {
    font-size: 16px;
  }

  .brand-title-full {
    display: none;
  }

  .brand-title-short {
    display: block;
  }

  .brand-subtitle {
    display: none;
  }

  .hero {
    background:
      linear-gradient(180deg, rgba(8, 19, 30, 0.96), rgba(8, 19, 30, 0.78)),
      url("../img/product-main-die.png") center bottom / 76% auto no-repeat,
      #101820;
  }

  .hero .container {
    min-height: 640px;
    align-items: start;
    padding-top: 62px;
  }

  .hero-copy,
  .page-hero p {
    font-size: 16px;
  }

  .hero-actions,
  .section-actions {
    flex-direction: column;
  }

  .hero-metrics,
  .grid-4,
  .grid-3,
  .about-layout,
  .contact-layout,
  .footer-grid,
  .category-list,
  .field-row {
    grid-template-columns: 1fr;
  }

  .section {
    padding: 52px 0;
  }

  .section-head {
    display: block;
  }

  .cta-band {
    padding: 28px;
  }

  .page-hero {
    padding: 52px 0;
    background:
      linear-gradient(180deg, rgba(16, 24, 32, 0.94), rgba(16, 24, 32, 0.8)),
      var(--ink);
  }

  .qr-box {
    grid-template-columns: 92px 1fr;
  }

  .qr-box img {
    width: 92px;
    height: 92px;
  }

  .mobile-contact-bar {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 30;
    width: 100vw;
    max-width: 100vw;
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    background: var(--white);
    box-shadow: 0 -10px 28px rgba(16, 24, 32, 0.16);
  }

  .mobile-contact-bar a {
    min-width: 0;
    min-height: 60px;
    display: grid;
    place-items: center;
    color: var(--ink);
    border-right: 1px solid var(--line);
    font-size: 14px;
    font-weight: 800;
  }

  .mobile-contact-bar a:last-child {
    border-right: 0;
    color: var(--white);
    background: var(--danger);
  }
}