/* ========================================
   噪声振动之家 - 主样式表
   风格: 黑白极简 × 工业精密感
   ======================================== */

/* ===== CSS VARIABLES ===== */
:root {
  /* Colors - B&W Core */
  --color-black: #000000;
  --color-near-black: #0a0a0a;
  --color-dark: #111111;
  --color-dark-gray: #1a1a1a;
  --color-gray-900: #222222;
  --color-gray-800: #333333;
  --color-gray-700: #444444;
  --color-gray-600: #666666;
  --color-gray-500: #4b5563;
  --color-gray-400: #6b7280;
  --color-gray-300: #cccccc;
  --color-gray-200: #e5e5e5;
  --color-gray-100: #f0f0f0;
  --color-white: #ffffff;

  /* Accent */
  --color-accent: #000000;
  --color-accent-light: #333333;

  /* Status */
  --color-hot: #ff3b3b;
  --color-new: #00c853;

  /* Typography */
  --font-mono: 'SFMono-Regular', Menlo, Consolas, 'Courier New', monospace;
  --font-serif: 'Source Han Serif SC', 'Songti SC', 'SimSun', serif;
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Layout */
  --container-width: 1200px;
  --container-padding: 1.5rem;
  --header-height: 72px;

  /* Animation */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --duration-fast: 150ms;
  --duration-normal: 300ms;
  --duration-slow: 500ms;
}

/* ===== LANGUAGE SWITCHER ===== */
.lang-switcher {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  background: var(--color-gray-100);
  border-radius: 4px;
  padding: 2px;
}

.lang-btn {
  padding: 0.35rem 0.75rem;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--color-gray-600);
  background: transparent;
  border: none;
  border-radius: 3px;
  cursor: pointer;
  transition: all var(--duration-fast) ease;
}

.lang-btn:hover {
  color: var(--color-dark);
}

.lang-btn.active {
  background: var(--color-white);
  color: var(--color-dark);
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

@media (max-width: 768px) {
  .lang-switcher {
    order: -1;
    margin-right: 0.5rem;
  }
}

/* ===== RESET & BASE ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-dark);
  background-color: var(--color-white);
  overflow-x: hidden;
}

::selection {
  background: var(--color-black);
  color: var(--color-white);
}

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

a:hover {
  color: var(--color-gray-600);
}

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

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

ul, ol {
  list-style: none;
}

/* ===== UTILITIES ===== */
.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.section {
  padding: var(--space-4xl) 0;
}

@media (max-width: 768px) {
  .section {
    padding: var(--space-2xl) 0;
  }
}

.section-header {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  margin-bottom: var(--space-2xl);
  flex-wrap: wrap;
}

.section-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: var(--color-gray-500);
  background: var(--color-gray-100);
  padding: 0.25rem 0.75rem;
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 600;
  letter-spacing: -0.02em;
}

.section-more {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-gray-500);
}

.section-more:hover {
  color: var(--color-black);
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  padding: 0.875rem 1.75rem;
  border-radius: 0;
  transition: all var(--duration-normal) var(--ease-out);
}

.btn-primary {
  background: var(--color-black);
  color: var(--color-white);
  border: 2px solid var(--color-black);
}

.btn-primary:hover {
  background: var(--color-gray-800);
  border-color: var(--color-gray-800);
  color: var(--color-white);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.15);
}

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

.btn-outline:hover {
  background: var(--color-black);
  color: var(--color-white);
}

/* ===== HEADER ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  z-index: 1000;
  border-bottom: 1px solid var(--color-gray-200);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo-icon {
  width: 32px;
  height: 32px;
  color: var(--color-black);
}

.logo-text {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.logo-sub {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--color-gray-500);
  display: none;
}

@media (min-width: 1024px) {
  .logo-sub {
    display: block;
  }
}

.main-nav {
  display: none;
  gap: var(--space-xl);
}

@media (min-width: 1024px) {
  .main-nav {
    display: flex;
  }
}

.nav-link {
  position: relative;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--color-gray-700);
  padding: 0.5rem 0;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-black);
  transition: width var(--duration-normal) var(--ease-out);
}

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

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

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.search-btn {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gray-700);
  transition: color var(--duration-fast) ease;
}

.search-btn:hover {
  color: var(--color-black);
}

.menu-toggle {
  width: 40px;
  height: 40px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
}

.menu-toggle span {
  width: 20px;
  height: 2px;
  background: var(--color-black);
  transition: all var(--duration-fast) ease;
}

.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);
}

@media (min-width: 1024px) {
  .menu-toggle {
    display: none;
  }
}

/* Mobile Nav */
.main-nav.mobile-open {
  display: flex;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--color-white);
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-xl);
  z-index: 999;
}

.main-nav.mobile-open .nav-link {
  font-size: 1.25rem;
}

/* Search Overlay */
.search-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 100vh; height: 100dvh;
  background: var(--color-white);
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 120px;
  z-index: 1001;
  opacity: 0;
  visibility: hidden;
  transition: all var(--duration-normal) ease;
}

.search-overlay.active {
  opacity: 1;
  visibility: visible;
}

.search-box {
  display: flex;
  align-items: center;
  width: 100%;
  max-width: 600px;
  padding: 0 var(--container-padding);
}

.search-box input {
  flex: 1;
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 300;
  border: none;
  border-bottom: 2px solid var(--color-black);
  padding: 1rem 0;
  outline: none;
  background: transparent;
}

.search-box input::placeholder {
  color: var(--color-gray-400);
}

.search-close {
  width: 48px;
  height: 48px;
  font-size: 1.5rem;
  color: var(--color-gray-500);
  margin-left: 1rem;
}

.search-close:hover {
  color: var(--color-black);
}

/* ===== HERO ===== */
.hero {
  position: relative;
  min-height: 100vh; min-height: 100dvh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: calc(var(--header-height) + var(--space-2xl)) var(--container-padding) var(--space-2xl);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
}

#wave-canvas {
  width: 100%;
  height: 100%;
  opacity: 0.08;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-3xl) 0;
}

.hero-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.25em;
  color: var(--color-gray-500);
  margin-bottom: var(--space-xl);
  display: inline-block;
  border: 1px solid var(--color-gray-300);
  padding: 0.4rem 1.2rem;
  border-radius: 2px;
  background: rgba(255,255,255,0.8);
  backdrop-filter: blur(8px);
  opacity: 0;
  animation: fadeInUp 0.8s var(--ease-out) 0.2s forwards;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2.5rem, 10vw, 5rem);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-xl);
}

.hero-title .line {
  display: block;
  opacity: 0;
  animation: fadeInUp 0.8s var(--ease-out) forwards;
}

.hero-title .line:nth-child(1) {
  animation-delay: 0.3s;
}

.hero-title .line:nth-child(2) {
  animation-delay: 0.45s;
}

.hero-title .accent {
  font-style: italic;
  font-weight: 300;
}

.hero-desc {
  font-size: 1.125rem;
  color: var(--color-gray-600);
  line-height: 1.8;
  margin-bottom: var(--space-2xl);
  opacity: 0;
  animation: fadeInUp 0.8s var(--ease-out) 0.6s forwards;
}

.hero-cta {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
  opacity: 0;
  animation: fadeInUp 0.8s var(--ease-out) 0.75s forwards;
}

.hero-scroll-hint {
  position: absolute;
  bottom: var(--space-2xl);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-gray-400);
}

.hero-scroll-hint span {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.2em;
}

.scroll-line {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, var(--color-gray-400), transparent);
  animation: scrollLine 2s ease-in-out infinite;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scrollLine {
  0%, 100% {
    transform: scaleY(1);
    opacity: 1;
  }
  50% {
    transform: scaleY(0.5);
    opacity: 0.5;
  }
}

/* ===== TICKER ===== */
.ticker-wrap {
  background: var(--color-black);
  padding: 0.75rem 0;
  overflow: hidden;
}

.ticker-track {
  display: flex;
  gap: var(--space-xl);
  animation: ticker 30s linear infinite;
  white-space: nowrap;
}

.ticker-track span {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--color-white);
  opacity: 0.8;
}

.ticker-track .sep {
  color: var(--color-gray-600);
}

@keyframes ticker {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(-50%);
  }
}

/* ===== MODULES GRID ===== */
.modules-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
}

@media (max-width: 1024px) {
  .modules-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .modules-grid {
    grid-template-columns: 1fr;
  }
}

.module-card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: var(--space-xl);
  background: var(--color-white);
  border: 1px solid var(--color-gray-200);
  transition: all var(--duration-normal) var(--ease-out);
  overflow: hidden;
}

.module-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 0;
  background: var(--color-black);
  transition: height var(--duration-normal) var(--ease-out);
}

.module-card:hover {
  border-color: var(--color-black);
  transform: translateY(-4px);
  box-shadow: 0 20px 40px rgba(0,0,0,0.08);
}

.module-card:hover::before {
  height: 100%;
}

.module-card.featured {
  background: var(--color-black);
  border-color: var(--color-black);
  color: var(--color-white);
}

.module-card.featured::before {
  background: var(--color-white);
}

.module-card.featured:hover {
  background: var(--color-gray-900);
}

.card-num {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--color-gray-400);
  margin-bottom: var(--space-lg);
}

.module-card.featured .card-num {
  color: var(--color-gray-600);
}

.card-icon {
  color: var(--color-black);
  margin-bottom: var(--space-lg);
  transition: transform var(--duration-normal) var(--ease-out);
}

.module-card:hover .card-icon {
  transform: scale(1.1) translateY(-3px);
}

.module-card.featured .card-icon {
  color: var(--color-white);
}

.module-card.featured:hover .card-icon {
  transform: scale(1.1) translateY(-3px);
}

.card-title {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.card-desc {
  font-size: 0.9rem;
  color: var(--color-gray-600);
  line-height: 1.6;
  flex: 1;
}

.module-card.featured .card-desc {
  color: var(--color-gray-400);
}

.card-badge {
  position: absolute;
  top: var(--space-lg);
  right: var(--space-lg);
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--color-hot);
  background: rgba(255, 59, 59, 0.1);
  padding: 0.25rem 0.5rem;
}

.module-card.featured .card-badge {
  background: rgba(255, 59, 59, 0.2);
}

.card-arrow {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  color: var(--color-gray-400);
  margin-top: var(--space-lg);
  transition: transform var(--duration-fast) ease;
}

.module-card:hover .card-arrow {
  transform: translateX(8px);
}

.module-card.featured .card-arrow {
  color: var(--color-gray-500);
}

/* ===== LATEST NEWS ===== */
.latest-news {
  background: var(--color-gray-100);
}

.news-list {
  display: flex;
  flex-direction: column;
}

.news-item {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: var(--space-lg);
  align-items: center;
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--color-gray-200);
  transition: background var(--duration-fast) ease;
}

.news-item:hover {
  background: var(--color-white);
  margin: 0 calc(-1 * var(--container-padding));
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

.news-item:last-child {
  border-bottom: none;
}

.news-cat {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--color-white);
  background: var(--color-black);
  padding: 0.3rem 0.85rem;
  white-space: nowrap;
  border-radius: 2px;
}

.news-cat.cat-policy { background: #2563eb; }
.news-cat.cat-academic { background: #7c3aed; }
.news-cat.cat-industry { background: #059669; }
.news-cat.cat-standard { background: #d97706; }
.news-cat.cat-case { background: #dc2626; }
.news-cat.cat-review { background: #0891b2; }

.news-title {
  font-size: 1rem;
  font-weight: 500;
  transition: color var(--duration-fast) ease;
}

.news-item:hover .news-title {
  color: var(--color-black);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.news-date {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-gray-500);
  white-space: nowrap;
}

@media (max-width: 640px) {
  .news-item {
    grid-template-columns: 1fr;
    gap: var(--space-sm);
  }
  .news-date {
    order: -1;
  }
}

/* ===== QUICK CALC ===== */
.quick-calc {
  background: var(--color-near-black);
  color: var(--color-white);
}

.calc-wrapper {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: start;
}

@media (max-width: 1024px) {
  .calc-wrapper {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
  }
}

.calc-info .section-tag {
  background: var(--color-gray-800);
  color: var(--color-gray-400);
}

.calc-info .section-title {
  color: var(--color-white);
}

.calc-info p {
  color: var(--color-gray-400);
  margin-top: var(--space-md);
}

.calc-panel {
  background: var(--color-dark-gray);
  border: 1px solid var(--color-gray-800);
  padding: var(--space-xl);
}

.calc-row {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-gray-800);
}

.calc-row label {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-gray-400);
  width: 60px;
}

.spl-input {
  flex: 1;
  background: var(--color-gray-900);
  border: 1px solid var(--color-gray-700);
  color: var(--color-white);
  font-family: var(--font-mono);
  font-size: 1rem;
  padding: 0.5rem 0.75rem;
  text-align: right;
  outline: none;
  transition: border-color var(--duration-fast) ease;
}

.spl-input:focus {
  border-color: var(--color-white);
}

.spl-input::-webkit-inner-spin-button {
  display: none;
}

.unit {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-gray-500);
  width: 40px;
}

.calc-btn {
  width: 100%;
  margin-top: var(--space-lg);
}

.calc-result {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-top: var(--space-lg);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-gray-800);
}

.result-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-gray-500);
}

.result-value {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-white);
  margin-left: auto;
}

.result-unit {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-gray-500);
}

/* ===== WECHAT SECTION ===== */
.wechat-section {
  background: var(--color-white);
}

.wechat-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
}

@media (max-width: 768px) {
  .wechat-grid {
    grid-template-columns: 1fr;
  }
}

.wechat-card {
  text-align: center;
  padding: var(--space-xl);
  border: 1px solid var(--color-gray-200);
  transition: all var(--duration-normal) var(--ease-out);
}

.wechat-card:hover {
  border-color: var(--color-black);
  transform: translateY(-4px);
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
}

.wechat-icon {
  width: 60px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--space-lg);
  background: var(--color-gray-100);
  color: var(--color-black);
}

.wechat-card h3 {
  font-family: var(--font-serif);
  font-size: 1.125rem;
  margin-bottom: var(--space-sm);
}

.wechat-card p {
  font-size: 0.85rem;
  color: var(--color-gray-600);
  line-height: 1.6;
}

.qr-placeholder {
  margin-top: var(--space-lg);
  width: 120px;
  height: 120px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-white);
  margin-left: auto;
  margin-right: auto;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--color-gray-700);
  border: 2px solid var(--color-gray-200);
  border-radius: 8px;
  position: relative;
  overflow: hidden;
  /* CSS-generated QR pattern */
  background-image:
    linear-gradient(45deg, #000 25%, transparent 25%),
    linear-gradient(-45deg, #000 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #000 75%),
    linear-gradient(-45deg, transparent 75%, #000 75%);
  background-position: 0 0, 0 10px, 10px -10px, -10px 0;
  background-size: 20px 20px;
  opacity: 0.85;
}

.qr-placeholder::before {
  content: '';
  position: absolute;
  top: 6px; left: 6px;
  width: 24px; height: 24px;
  border: 4px solid #000;
  border-radius: 3px;
  background: #fff;
}

.qr-placeholder::after {
  content: '';
  position: absolute;
  top: 6px; right: 6px;
  width: 24px; height: 24px;
  border: 4px solid #000;
  border-radius: 3px;
  background: #fff;
}

/* Bottom-left QR corner (via box-shadow trick on span) */
.qr-placeholder span {
  position: relative;
  z-index: 1;
  padding: 4px 8px;
  background: rgba(255,255,255,0.9);
  border-radius: 4px;
  font-weight: 600;
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Bottom-left QR corner marker */
.qr-placeholder .qr-corner-bl {
  position: absolute;
  bottom: 6px; left: 6px;
  width: 24px; height: 24px;
  border: 4px solid #000;
  border-radius: 3px;
  background: #fff;
}

.qr-placeholder.active {
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  color: var(--color-white);
  border-color: var(--color-black);
  background-image: none;
}

.qr-placeholder.active::before,
.qr-placeholder.active::after {
  border-color: #fff;
  background: rgba(255,255,255,0.15);
}

/* ===== UNIFIED QR IMAGE (公众号 / 小程序码) =====
   全站统一引用真实二维码图片，替代 .qr-placeholder 的伪二维码。
   路径使用站点根相对 /assets/images/...，确保根目录页与子目录页(如 sim/*)均正确加载。 */
.qr-image {
  display: block;
  width: 132px;
  height: 132px;
  object-fit: contain;
  margin: var(--space-lg) auto 0;
  background: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: 8px;
  padding: 6px;
}

.qr-caption {
  margin-top: 0.5rem;
  font-size: 0.8rem;
  color: var(--color-gray-600);
  text-align: center;
  line-height: 1.5;
}

/* ===== FOOTER ===== */
.site-footer {
  background: var(--color-near-black);
  color: var(--color-white);
  padding: var(--space-3xl) 0 var(--space-xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}

@media (max-width: 1024px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
  }
}

@media (max-width: 640px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

.footer-brand .logo {
  margin-bottom: var(--space-md);
}

.footer-brand .logo-icon {
  color: var(--color-white);
}

.footer-brand .logo-text {
  color: var(--color-white);
}

.footer-desc {
  font-size: 0.9rem;
  color: var(--color-gray-500);
  line-height: 1.7;
}

.footer-links h4 {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--color-gray-400);
  margin-bottom: var(--space-lg);
}

.footer-links ul {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.footer-links a {
  font-size: 0.9rem;
  color: var(--color-gray-500);
  transition: color var(--duration-fast) ease;
}

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

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-sm);
  padding-top: var(--space-xl);
  border-top: 1px solid var(--color-gray-800);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-gray-500);
}

.footer-icp a {
  color: var(--color-gray-400) !important;
  text-decoration: underline !important;
  text-decoration-style: dotted !important;
  text-underline-offset: 3px !important;
  transition: color 0.2s ease !important;
}

.footer-icp a:hover {
  color: var(--color-blue-400) !important;
  text-decoration-style: solid !important;
}

@media (max-width: 640px) {
  .footer-bottom {
    flex-direction: column;
    gap: var(--space-sm);
    text-align: center;
  }
}

/* ===== RESPONSIVE ADJUSTMENTS ===== */
@media (max-width: 640px) {
  :root {
    --header-height: 60px;
    --container-padding: 1rem;
  }
  
  html {
    font-size: 15px;
  }
  
  .hero-cta {
    flex-direction: column;
    width: 100%;
  }
  
  .hero-cta .btn {
    width: 100%;
  }
  
  .hero-scroll-hint {
    display: none;
  }
  
  .hero-title {
    font-size: clamp(2rem, 8vw, 3rem);
  }
  
  .hero-desc {
    font-size: 0.95rem;
  }
  
  /* Module cards stack vertically on mobile */
  .modules-grid {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }
  
  .module-card {
    padding: var(--space-lg);
  }
  
  .card-title {
    font-size: 1.1rem;
  }
  
  /* News list - compact */
  .news-item {
    grid-template-columns: 1fr;
    gap: var(--space-xs);
    padding: var(--space-md) 0;
  }
  
  .news-date {
    order: -1;
    font-size: 0.7rem;
  }
  
  .news-cat {
    display: inline-block;
    width: fit-content;
    font-size: 0.65rem;
    padding: 0.15rem 0.5rem;
  }
  
  .news-title {
    font-size: 0.95rem;
  }
  
  /* Quick calc section */
  .calc-panel {
    padding: var(--space-md);
  }
  
  /* Wechat cards */
  .wechat-grid {
    grid-template-columns: 1fr;
  }
  
  /* Footer */
  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }
  
  .footer-bottom {
    flex-direction: column;
    gap: var(--space-sm);
    text-align: center;
  }
  
  /* Section spacing */
  .section {
    padding: var(--space-xl) 0;
  }
  
  /* Section headers */
  .section-header {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-sm);
  }
  
  .section-more {
    margin-left: 0;
  }
  
  /* QR placeholders */
  .qr-placeholder {
    width: 100px;
    height: 100px;
  }
}

/* Tablet adjustments */
@media (min-width: 641px) and (max-width: 1024px) {
  .modules-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
  }
  
  .wechat-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ===== ENHANCEMENTS (竞品对标改进) ===== */

/* 导航链接高亮当前页 */
.nav-link.active {
  color: var(--color-black);
  font-weight: 500;
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--color-black);
}

/* 模块卡片序号悬浮效果 */
.module-card:hover .card-num {
  color: var(--color-black);
  transition: color var(--duration-fast) ease;
}

.module-card.featured:hover .card-num {
  color: var(--color-white);
}

/* section-header 动画入场 */
.section-header {
  opacity: 0;
  animation: fadeInUp 0.6s var(--ease-out) forwards;
}

.modules .section-header { animation-delay: 0.1s; }
.latest-news .section-header { animation-delay: 0.2s; }
.quick-calc .section-header { animation-delay: 0.3s; }
.wechat-section .section-header { animation-delay: 0.4s; }

/* 新闻列表交错动画 */
.news-item {
  opacity: 0;
  animation: fadeInUp 0.5s var(--ease-out) forwards;
}

.news-list .news-item:nth-child(1) { animation-delay: 0.05s; }
.news-list .news-item:nth-child(2) { animation-delay: 0.1s; }
.news-list .news-item:nth-child(3) { animation-delay: 0.15s; }
.news-list .news-item:nth-child(4) { animation-delay: 0.2s; }
.news-list .news-item:nth-child(5) { animation-delay: 0.25s; }

/* 页脚链接 hover */
.footer-links a:hover {
  color: var(--color-black);
  padding-left: 4px;
  transition: all var(--duration-fast) ease;
}

/* 备案号增强 */
.footer-icp a {
  transition: color var(--duration-fast) ease;
}

.footer-icp a:hover {
  color: var(--color-blue-400) !important;
}

/* 响应式：小屏隐藏部分装饰 */
@media (max-width: 768px) {
  .hero-label {
    font-size: 0.6rem;
    padding: 0.3rem 0.8rem;
    letter-spacing: 0.15em;
  }
  
  .ticker-wrap {
    display: none;
  }
}
.footer-rss{margin-left:12px;color:#4a9eff;text-decoration:none;font-size:.85em;}
.footer-rss:hover{text-decoration:underline;}
/* ===== Mini-program landing page (噪声振动News) ===== */
.hero-badge{display:inline-block;border:1px solid var(--color-gray-300);color:var(--color-gray-600);
  font-family:var(--font-mono);font-size:.7rem;letter-spacing:.15em;text-transform:uppercase;
  padding:.3rem .7rem;margin-bottom:1.25rem;}
.hero-sub{color:var(--color-gray-500);font-size:1.1rem;line-height:1.7;max-width:42rem;margin:0 auto;}
.hero-actions{display:flex;gap:1rem;justify-content:center;flex-wrap:wrap;margin-top:2rem;}
.btn-ghost{background:transparent;color:var(--color-black);border:1px solid var(--color-black);}
.btn-ghost:hover{background:var(--color-black);color:var(--color-white);}
.section-alt{background:var(--color-gray-100);}
.section-head{text-align:center;margin-bottom:3rem;}
.section-head .section-title{margin-bottom:.5rem;}
.section-desc{color:var(--color-gray-500);font-size:1rem;}
.miniapp-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:2rem;max-width:56rem;margin:0 auto;}
.miniapp-card{border:1px solid var(--color-gray-200);background:var(--color-white);padding:2.5rem 2rem;
  text-align:center;}
.miniapp-card h3{font-family:var(--font-mono);font-size:1.05rem;margin:1.5rem 0 .75rem;}
.miniapp-card p{color:var(--color-gray-500);font-size:.95rem;line-height:1.7;}
.qr-box{border:2px dashed var(--color-gray-300);max-width:240px;aspect-ratio:1/1;margin:0 auto;
  display:flex;align-items:center;justify-content:center;background:var(--color-white);}
.qr-box img{width:100%;height:100%;object-fit:contain;}
.qr-placeholder{color:var(--color-gray-400);font-family:var(--font-mono);font-size:.9rem;line-height:1.6;text-align:center;}
.search-visual{border:1px solid var(--color-gray-200);max-width:240px;margin:0 auto;padding:2rem 1rem;
  display:flex;align-items:center;justify-content:center;background:var(--color-white);}
.search-keyword{font-family:var(--font-mono);font-size:1.05rem;font-weight:700;border-bottom:2px solid var(--color-black);padding-bottom:.3rem;}
.feature-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:1.5rem;}
.feature-card{border:1px solid var(--color-gray-200);background:var(--color-white);padding:2rem 1.5rem;transition:transform .2s,border-color .2s;}
.feature-card:hover{transform:translateY(-4px);border-color:var(--color-black);}
.feature-icon{font-size:1.8rem;margin-bottom:1rem;}
.feature-card h3{font-family:var(--font-mono);font-size:1rem;margin-bottom:.6rem;}
.feature-card p{color:var(--color-gray-500);font-size:.9rem;line-height:1.6;}
.cta-section{background:var(--color-black);color:var(--color-white);padding:4rem 0;}
.cta-inner{text-align:center;max-width:40rem;margin:0 auto;}
.cta-inner h2{font-family:var(--font-mono);font-size:1.8rem;margin-bottom:1rem;}
.cta-inner p{color:var(--color-gray-400);margin-bottom:2rem;}
.cta-section .btn-primary{background:var(--color-white);color:var(--color-black);}
.cta-section .btn-primary:hover{background:var(--color-gray-200);}
@media(max-width:768px){.miniapp-grid{grid-template-columns:1fr;}.feature-grid{grid-template-columns:repeat(2,1fr);}}

/* ===== NEWS SEARCH BAR ===== */
.news-search-bar{display:flex;align-items:center;gap:.75rem;margin:1.5rem 0;flex-wrap:wrap;background:var(--color-white,#fff);border:1px solid var(--color-gray-300,#d1d5db);border-radius:10px;padding:.4rem .9rem}
.news-search-bar .news-search-icon{color:var(--color-gray-500,#6b7280);flex:none}
.news-search-bar input[type=search]{flex:1;min-width:220px;border:none;outline:none;font-size:1rem;background:transparent;color:var(--color-dark,#111);padding:.5rem 0}
.news-search-count{color:var(--color-gray-500,#6b7280);font-size:.85rem;white-space:nowrap}
.news-empty{color:var(--color-gray-500,#6b7280);margin:1rem 0}

/* ===== 文章小节锚点：避免被吸顶导航遮挡 ===== */
.article-content h2[id],.article-content h3[id]{scroll-margin-top:90px}
.toc-list a{color:inherit}
.toc-list a:hover{text-decoration:underline}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}

/* ===== 计算器分类筛选 ===== */
.calc-cats{display:flex;flex-wrap:wrap;gap:.5rem;margin-bottom:1.25rem}
.calc-cat-btn{font-family:inherit;font-size:.85rem;padding:.4rem .95rem;background:#fff;border:1px solid var(--color-gray-300,#d1d5db);border-radius:999px;color:#374151;cursor:pointer;transition:all .15s ease}
.calc-cat-btn:hover{border-color:#111827;color:#111827}
.calc-cat-btn.active{background:#111827;border-color:#111827;color:#fff}
.calc-cat-btn span{font-family:var(--font-mono);font-size:.72rem;opacity:.65;margin-left:.3rem}

/* ===== 学习中心：资源卡 / FAQ ===== */
.res-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1rem}
.res-card{border:1px solid var(--color-gray-200);background:var(--color-white);padding:1.25rem;display:block;color:inherit;text-decoration:none;transition:border-color .2s,transform .2s}
.res-card:hover{border-color:var(--color-black);transform:translateY(-3px);text-decoration:none}
.res-card h3{font-family:var(--font-mono);font-size:.95rem;margin-bottom:.35rem}
.res-card p{font-size:.82rem;color:var(--color-gray-500);margin:0;line-height:1.6}
.faq-list{max-width:840px;margin:0 auto}
.faq-list details{border:1px solid var(--color-gray-200);background:var(--color-white);margin-bottom:.75rem;border-radius:6px}
.faq-list summary{cursor:pointer;padding:1rem 1.25rem;font-weight:600;font-size:.95rem;list-style:none}
.faq-list summary::-webkit-details-marker{display:none}
.faq-list summary::after{content:'+';float:right;color:var(--color-gray-400);font-weight:400}
.faq-list details[open] summary::after{content:'\2212'}
.faq-list details p{margin:0;padding:0 1.25rem 1rem;color:var(--color-gray-500);font-size:.9rem;line-height:1.75}
@media(max-width:768px){.res-grid{grid-template-columns:1fr}}

/* ===== 引流交互组件（阅读进度/分享/上下篇/订阅） ===== */
.reading-progress{position:fixed;top:0;left:0;right:0;height:3px;z-index:9999;pointer-events:none;background:transparent}
.reading-progress-fill{height:100%;width:0;background:var(--color-black,#111);transition:width .08s linear}
.share-bar{display:flex;align-items:center;gap:.5rem;flex-wrap:wrap;margin:2.5rem 0 1.25rem;padding-top:1.5rem;border-top:1px solid var(--color-gray-200,#e5e7eb)}
.share-label{font-size:.85rem;color:var(--color-gray-500,#6b7280)}
.share-btn{font-size:.85rem;padding:.45rem .9rem;border:1px solid var(--color-gray-300,#d1d5db);background:var(--color-white,#fff);color:var(--color-dark,#111);border-radius:6px;cursor:pointer;transition:background .2s,color .2s,border-color .2s}
.share-btn:hover{background:var(--color-black,#111);color:var(--color-white,#fff);border-color:var(--color-black,#111)}
.article-nav{display:grid;grid-template-columns:1fr 1fr;gap:1rem;margin:1.25rem 0 2rem}
.article-nav a{display:block;padding:1rem;border:1px solid var(--color-gray-200,#e5e7eb);border-radius:8px;text-decoration:none;color:var(--color-dark,#111);transition:border-color .2s,box-shadow .2s;min-width:0}
.article-nav a:hover{border-color:var(--color-black,#111);box-shadow:0 2px 8px rgba(0,0,0,.08)}
.article-nav .an-prev{text-align:left}
.article-nav .an-next{text-align:right}
.article-nav .an-dir{display:block;font-size:.75rem;color:var(--color-gray-400,#9ca3af);margin-bottom:.35rem}
.article-nav .an-title{display:block;font-weight:600;font-size:.9rem;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.subscribe-cta{display:flex;align-items:center;gap:.75rem;margin-top:.75rem}
.subscribe-btn{display:inline-block;padding:.4rem .9rem;background:var(--color-black,#111);color:var(--color-white,#fff);border-radius:6px;font-size:.8rem;text-decoration:none;transition:opacity .2s}
.subscribe-btn:hover{opacity:.8;color:var(--color-white,#fff)}
.subscribe-rss{font-size:.75rem;color:var(--color-gray-400,#9ca3af);text-decoration:none;font-family:var(--font-mono,monospace)}
.subscribe-rss:hover{color:var(--color-black,#111)}
@media(max-width:640px){.article-nav{grid-template-columns:1fr}}

/* ===== 站内搜索结果面板（全站通用） ===== */
.search-results{display:none;width:100%;max-width:600px;margin-top:1.25rem;max-height:62vh;overflow-y:auto;background:var(--color-white,#fff);border:1px solid var(--color-gray-200,#e5e7eb);border-radius:10px;box-shadow:0 8px 30px rgba(0,0,0,.08)}
.search-meta{padding:.7rem 1rem;font-size:.75rem;color:var(--color-gray-400,#9ca3af);border-bottom:1px solid var(--color-gray-200,#e5e7eb)}
.search-empty{padding:1.5rem 1rem;text-align:center;font-size:.9rem;color:var(--color-gray-500,#6b7280)}
.search-item{display:block;padding:.85rem 1rem;text-decoration:none;color:inherit;border-bottom:1px solid var(--color-gray-100,#f3f4f6);transition:background .15s}
.search-item:last-child{border-bottom:none}
.search-item:hover{background:var(--color-gray-50,#f9fafb)}
.search-item-cat{display:block;font-size:.72rem;color:var(--color-gray-400,#9ca3af);font-family:var(--font-mono,monospace)}
.search-item-title{display:block;font-weight:600;font-size:.95rem;color:var(--color-black,#111);margin:.2rem 0}
.search-item-desc{display:block;font-size:.82rem;color:var(--color-gray-500,#6b7280);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
@media(max-width:640px){.search-box input{font-size:1.35rem}.search-results{max-height:56vh}}