/* ============================================================
   Wuhan Jiesu Shou E-commerce Co., Ltd. — Global Styles
   素雅侘寂质感新零售商务风 · 低饱和大地素雅色系
   ============================================================ */

/* --- CSS Variables / Design Tokens --- */
:root {
  /* Primary Palette */
  --clay-brown:       #A68C78;
  --mist-beige:       #D9CFC4;
  --overlay-dark:     rgba(26, 26, 26, 0.52);
  --card-bg:          rgba(255, 255, 255, 0.06);
  --card-border:      rgba(217, 207, 196, 0.18);

  /* Text Hierarchy */
  --title-white:      #F4F1ED;
  --body-mist:        #D8D2CD;
  --sub-gray:         #A8A29D;

  /* Layout */
  --section-min-h:    100vh;
  --card-radius:      14px;
  --card-backdrop:    blur(18px) saturate(110%);
  --transition-base:  0.45s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: "Helvetica Neue", "Segoe UI", "PingFang SC", "Microsoft YaHei",
               "Hiragino Sans GB", Arial, sans-serif;
  font-weight: 300;
  line-height: 1.72;
  color: var(--body-mist);
  background: #1a1a1a;
  overflow-x: hidden;
}

/* --- Section Base (Full-Screen Background Layer) --- */
.section {
  position: relative;
  min-height: var(--section-min-h);
  display: flex;
  align-items: center;
  justify-content: center;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  overflow: hidden;
}

/* --- Overlay (Universal Dark Mask) --- */
.section::before {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--overlay-dark);
  z-index: 1;
  pointer-events: none;
}

.section > .section-content {
  position: relative;
  z-index: 2;
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 100px 32px;
}

/* --- Frosted Glass Card --- */
.card {
  background: var(--card-bg);
  backdrop-filter: var(--card-backdrop);
  -webkit-backdrop-filter: var(--card-backdrop);
  border: 1px solid var(--card-border);
  border-radius: var(--card-radius);
  padding: 40px 36px;
  transition: transform var(--transition-base),
              box-shadow var(--transition-base),
              border-color var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.35);
  border-color: rgba(166, 140, 120, 0.32);
}

/* --- Typography --- */
.text-title {
  font-size: clamp(2rem, 5vw, 3.6rem);
  font-weight: 400;
  letter-spacing: 0.03em;
  color: var(--title-white);
  line-height: 1.25;
}

.text-heading {
  font-size: clamp(1.4rem, 3.2vw, 2.2rem);
  font-weight: 400;
  letter-spacing: 0.04em;
  color: var(--title-white);
  line-height: 1.35;
}

.text-subheading {
  font-size: clamp(1rem, 2vw, 1.25rem);
  font-weight: 300;
  letter-spacing: 0.06em;
  color: var(--clay-brown);
  text-transform: uppercase;
}

.text-body {
  font-size: 1rem;
  font-weight: 300;
  line-height: 1.82;
  color: var(--body-mist);
}

.text-small {
  font-size: 0.875rem;
  font-weight: 300;
  color: var(--sub-gray);
}

/* --- Accent Divider --- */
.divider {
  width: 60px;
  height: 2px;
  background: var(--clay-brown);
  margin: 24px 0;
  border: none;
}

.divider.center {
  margin: 24px auto;
}

/* --- Buttons --- */
.btn {
  display: inline-block;
  padding: 13px 36px;
  font-size: 0.95rem;
  font-weight: 400;
  letter-spacing: 0.05em;
  text-decoration: none;
  border-radius: 4px;
  transition: all var(--transition-base);
  cursor: pointer;
}

.btn-primary {
  background: transparent;
  color: var(--title-white);
  border: 1px solid var(--clay-brown);
}

.btn-primary:hover {
  background: rgba(166, 140, 120, 0.18);
  border-color: var(--mist-beige);
}

.btn-outline {
  background: transparent;
  color: var(--mist-beige);
  border: 1px solid var(--mist-beige);
}

.btn-outline:hover {
  background: rgba(217, 207, 196, 0.12);
  border-color: var(--title-white);
  color: var(--title-white);
}

/* --- Navigation Bar --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 20px 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: background 0.5s ease, backdrop-filter 0.5s ease;
}

.nav.scrolled {
  background: rgba(26, 26, 26, 0.78);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.nav-brand {
  font-size: 1.05rem;
  font-weight: 400;
  letter-spacing: 0.08em;
  color: var(--title-white);
  text-decoration: none;
  white-space: nowrap;
}

.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  font-size: 0.85rem;
  font-weight: 300;
  letter-spacing: 0.06em;
  color: var(--body-mist);
  text-decoration: none;
  text-transform: uppercase;
  transition: color var(--transition-base);
  position: relative;
}

.nav-links a::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--clay-brown);
  transition: width var(--transition-base);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--title-white);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

/* --- Mobile Menu Toggle --- */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 1.5px;
  background: var(--title-white);
  transition: all var(--transition-base);
}

/* --- Footer --- */
.footer {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 40px 32px;
  background: rgba(20, 20, 20, 0.95);
  border-top: 1px solid rgba(166, 140, 120, 0.15);
}

.footer p {
  font-size: 0.8rem;
  color: var(--sub-gray);
  letter-spacing: 0.04em;
}

/* --- Scroll Reveal --- */
.reveal {
  opacity: 0;
  transform: translateY(36px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* --- Grid Layouts --- */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.grid-5 {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 22px;
}

/* --- Utility --- */
.text-center { text-align: center; }
.text-left   { text-align: left; }
.mt-16  { margin-top: 16px; }
.mt-24  { margin-top: 24px; }
.mt-32  { margin-top: 32px; }
.mt-48  { margin-top: 48px; }
.mt-64  { margin-top: 64px; }
.mb-16  { margin-bottom: 16px; }
.mb-24  { margin-bottom: 24px; }
.mb-32  { margin-bottom: 32px; }
.mb-48  { margin-bottom: 48px; }

/* --- Responsive --- */
@media (max-width: 1024px) {
  .grid-5 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .section > .section-content { padding: 80px 24px; }
}

@media (max-width: 768px) {
  .grid-2,
  .grid-3,
  .grid-5 { grid-template-columns: 1fr; }

  .nav { padding: 16px 24px; }
  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 260px;
    height: 100vh;
    flex-direction: column;
    background: rgba(20, 20, 20, 0.96);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    padding: 80px 32px 32px;
    gap: 28px;
    transition: right 0.4s ease;
  }
  .nav-links.open { right: 0; }

  .nav-toggle { display: flex; }

  .section > .section-content { padding: 72px 20px; }
}