/* ==========================================================================
   PackyMe Official Website - Minimalist Carbon & Zinc Theme (极简炭黑/曜石素雅风)
   Pure Vanilla CSS (Zero External Dependencies)
   ========================================================================== */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  /* Carbon & Zinc Palette */
  --bg-main: #fafafa;
  --bg-card: #ffffff;
  --bg-card-hover: #ffffff;
  --bg-secondary: #f4f4f5;
  --bg-glass: rgba(255, 255, 255, 0.88);
  
  --text-primary: #18181b;
  --text-secondary: #52525b;
  --text-muted: #71717a;
  --text-light: #a1a1aa;
  --text-accent: #18181b;

  --primary: #18181b;
  --primary-hover: #27272a;
  --primary-light: #f4f4f5;
  --accent-gray: #3f3f46;

  --border-color: #e4e4e7;
  --border-light: #f4f4f5;
  --border-active: #d4d4d8;

  --gradient-primary: linear-gradient(135deg, #18181b 0%, #3f3f46 100%);
  --gradient-text: linear-gradient(135deg, #18181b 40%, #52525b 100%);
  --gradient-card: linear-gradient(180deg, #ffffff 0%, #fafafa 100%);

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.04), 0 2px 4px -2px rgba(0, 0, 0, 0.02);
  --shadow-lg: 0 10px 25px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -4px rgba(0, 0, 0, 0.02);
  --shadow-hover: 0 12px 28px -4px rgba(0, 0, 0, 0.06);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --header-height: 72px;
}

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.65;
  overflow-x: hidden;
  position: relative;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Minimal Grid Lines */
.bg-mesh {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 0;
  background: 
    radial-gradient(circle at 15% 15%, rgba(24, 24, 27, 0.015) 0%, transparent 40%),
    radial-gradient(circle at 85% 25%, rgba(39, 39, 42, 0.015) 0%, transparent 45%);
}

.bg-grid-lines {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background-image: 
    linear-gradient(to right, rgba(0, 0, 0, 0.025) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(0, 0, 0, 0.025) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
  z-index: 0;
}

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition);
}

ul {
  list-style: none;
}

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

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  transition: var(--transition);
}

.site-header.scrolled {
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid var(--border-color);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.03);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
}

.brand-logo {
  display: flex;
  align-items: center;
  text-decoration: none;
}

.brand-logo img {
  width: 185px;
  height: auto;
  filter: brightness(0);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-link {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: 6px 0;
  transition: color 0.2s ease;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: width 0.25s ease;
  border-radius: 2px;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
}

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

.header-action {
  display: flex;
  align-items: center;
  gap: 16px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 9px 20px;
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 600;
  transition: var(--transition);
  white-space: nowrap;
}

.btn-primary {
  background: #18181b;
  color: #ffffff;
  box-shadow: 0 2px 6px rgba(24, 24, 27, 0.12);
}

.btn-primary:hover {
  background: #27272a;
  color: #ffffff;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(24, 24, 27, 0.2);
}

.btn-outline {
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  background: #ffffff;
  box-shadow: var(--shadow-sm);
}

.btn-outline:hover {
  border-color: #d4d4d8;
  background: #f4f4f5;
}

.btn-sm {
  padding: 6px 16px;
  font-size: 0.85rem;
}

.btn-lg {
  padding: 12px 28px;
  font-size: 0.98rem;
}

/* Mobile Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: 4px;
}

.menu-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  background-color: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}

.menu-toggle.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero-section {
  padding-top: calc(var(--header-height) + 60px);
  padding-bottom: 80px;
  position: relative;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 48px;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: #f4f4f5;
  border: 1px solid #e4e4e7;
  border-radius: var(--radius-full);
  color: #18181b;
  font-size: 0.82rem;
  font-weight: 600;
  margin-bottom: 24px;
}

.hero-badge .pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: #18181b;
  box-shadow: 0 0 6px rgba(24, 24, 27, 0.3);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(24, 24, 27, 0.4); }
  70% { transform: scale(1); box-shadow: 0 0 0 6px rgba(24, 24, 27, 0); }
  100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(24, 24, 27, 0); }
}

.hero-title {
  font-size: 3rem;
  line-height: 1.25;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 20px;
}

.hero-title .gradient-text {
  color: #18181b;
  background: linear-gradient(135deg, #18181b 30%, #52525b 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

.hero-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 32px;
  max-width: 580px;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 36px;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.hero-tag {
  font-size: 0.78rem;
  padding: 4px 10px;
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  font-weight: 500;
}

/* Hero Visual Box */
.hero-visual {
  position: relative;
}

.visual-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 26px;
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
}

.visual-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: #18181b;
}

.visual-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border-light);
}

.visual-dots {
  display: flex;
  gap: 6px;
}

.visual-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #e4e4e7;
}

.visual-dots span:nth-child(1) { background: #d4d4d8; }
.visual-dots span:nth-child(2) { background: #a1a1aa; }
.visual-dots span:nth-child(3) { background: #71717a; }

.visual-status {
  font-size: 0.72rem;
  font-family: var(--font-mono);
  color: #18181b;
  background: #f4f4f5;
  border: 1px solid #e4e4e7;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.visual-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.visual-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 14px;
  background: #fafafa;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  transition: var(--transition);
}

.visual-item:hover {
  border-color: #d4d4d8;
  background: #ffffff;
  box-shadow: var(--shadow-sm);
  transform: translateX(3px);
}

.visual-item-left {
  display: flex;
  align-items: center;
  gap: 12px;
}

.visual-icon {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: #f4f4f5;
  border: 1px solid #e4e4e7;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #18181b;
}

.visual-item-title {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-primary);
}

.visual-item-sub {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.visual-badge {
  font-size: 0.72rem;
  color: #27272a;
  background: #f4f4f5;
  border: 1px solid #e4e4e7;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-weight: 600;
}

/* ==========================================================================
   Section Common Styles
   ========================================================================== */
.section {
  padding: 80px 0;
  position: relative;
}

.section-alt {
  background: #ffffff;
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 50px auto;
}

.section-subtitle {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #71717a;
  margin-bottom: 10px;
}

.section-title {
  font-size: 2.1rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 14px;
  color: var(--text-primary);
}

.section-desc {
  font-size: 0.98rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ==========================================================================
   Core Features Grid (网关核心特性)
   ========================================================================== */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.service-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  transition: var(--transition);
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: var(--shadow-sm);
}

.service-card:hover {
  transform: translateY(-4px);
  border-color: #a1a1aa;
  box-shadow: var(--shadow-hover);
}

.service-icon-wrap {
  width: 50px;
  height: 50px;
  border-radius: 12px;
  background: #f4f4f5;
  border: 1px solid #e4e4e7;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #18181b;
  margin-bottom: 20px;
  transition: var(--transition);
}

.service-card:hover .service-icon-wrap {
  background: #18181b;
  color: #ffffff;
  border-color: #18181b;
}

.service-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.service-card-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 18px;
  flex-grow: 1;
}

.service-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding-top: 14px;
  border-top: 1px solid var(--border-light);
}

.service-tag {
  font-size: 0.72rem;
  padding: 2px 8px;
  background: #f4f4f5;
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  font-weight: 500;
}

/* ==========================================================================
   Solutions Showcase (解决方案)
   ========================================================================== */
.solutions-tabs {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-bottom: 36px;
  flex-wrap: wrap;
}

.tab-btn {
  padding: 9px 20px;
  border-radius: var(--radius-full);
  background: #ffffff;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.88rem;
  font-weight: 600;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.tab-btn:hover {
  background: #f4f4f5;
  color: var(--text-primary);
  border-color: #d4d4d8;
}

.tab-btn.active {
  background: #18181b;
  color: #ffffff;
  border-color: #18181b;
  box-shadow: 0 4px 12px rgba(24, 24, 27, 0.15);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
  animation: fadeIn 0.3s ease forwards;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

.solution-info h3 {
  font-size: 1.65rem;
  font-weight: 700;
  margin-bottom: 14px;
  color: var(--text-primary);
}

.solution-info p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 22px;
}

.solution-features {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}

.feature-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.feature-check {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: #f4f4f5;
  color: #18181b;
  border: 1px solid #e4e4e7;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 0.75rem;
  margin-top: 3px;
  font-weight: 700;
}

.solution-preview-box {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-md);
  position: relative;
}

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

.preview-card {
  background: #fafafa;
  border: 1px solid var(--border-light);
  padding: 18px;
  border-radius: var(--radius-md);
  text-align: center;
}

.preview-card-num {
  font-size: 1.5rem;
  font-weight: 800;
  color: #18181b;
  margin-bottom: 4px;
}

.preview-card-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* ==========================================================================
   About Us Section (关于我们)
   ========================================================================== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  align-items: center;
}

.about-text h3 {
  font-size: 1.85rem;
  font-weight: 700;
  margin-bottom: 18px;
  color: var(--text-primary);
}

.about-text p {
  font-size: 0.94rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 16px;
}

.about-highlights {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 28px;
}

.highlight-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 16px;
  background: #fafafa;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  text-align: left;
}

.highlight-icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: #f4f4f5;
  border: 1px solid #e4e4e7;
  color: #18181b;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.highlight-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.highlight-desc {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Contact Section (联系我们)
   ========================================================================== */
.contact-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 40px;
}

.contact-info-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.contact-info-title {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.contact-info-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.contact-list {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 14px;
}

.contact-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: #f4f4f5;
  border: 1px solid #e4e4e7;
  color: #18181b;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.contact-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 2px;
}

.contact-value {
  font-size: 0.9rem;
  color: var(--text-primary);
  font-weight: 600;
}

/* Form Box (Disabled) */
.contact-form-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  box-shadow: var(--shadow-sm);
}

.form-group {
  margin-bottom: 18px;
}

.form-label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--text-primary);
}

.form-control {
  width: 100%;
  padding: 10px 14px;
  background: #f4f4f5;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.88rem;
  font-family: inherit;
  transition: var(--transition);
}

.form-control:focus {
  outline: none;
  background: #ffffff;
  border-color: #18181b;
}

.form-control::placeholder {
  color: var(--text-light);
}

textarea.form-control {
  resize: vertical;
  min-height: 100px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

/* ==========================================================================
   Footer & ICP Compliance (极简页脚)
   ========================================================================== */
.site-footer {
  background: #ffffff;
  border-top: 1px solid var(--border-color);
  padding: 32px 0;
  position: relative;
  z-index: 1;
}

.footer-copyright {
  font-size: 0.85rem;
  color: var(--text-muted);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 20px;
  text-align: center;
}

/* Standard ICP text link */
.icp-link {
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.2s ease;
}

.icp-link:hover {
  color: var(--text-primary);
  text-decoration: none;
}

/* Back to Top */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: #ffffff;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  z-index: 999;
  box-shadow: var(--shadow-md);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: #18181b;
  color: #ffffff;
  border-color: #18181b;
  transform: translateY(-2px);
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 36px;
  }
  .services-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .about-grid {
    grid-template-columns: 1fr;
  }
  .about-highlights {
    grid-template-columns: repeat(2, 1fr);
  }
  .contact-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .menu-toggle {
    display: flex;
  }
  .nav-menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 24px;
    gap: 18px;
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.06);
    transform: translateY(-150%);
    opacity: 0;
    transition: var(--transition);
    pointer-events: none;
  }
  .nav-menu.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  .header-action .btn {
    display: none;
  }
  .hero-title {
    font-size: 2.2rem;
  }
  .services-grid {
    grid-template-columns: 1fr;
  }
  .tab-content.active {
    grid-template-columns: 1fr;
  }
  .about-highlights {
    grid-template-columns: 1fr;
  }
  .form-row {
    grid-template-columns: 1fr;
  }
}