/* ==========================================================================
   随便云官网 (suibiany.sbs) - 银河列车 (Galaxy Railway) 样式体系
   设计哲学：宇宙轨道科技感 + 极简阅读可用性 + 响应式触控友好
   ========================================================================== */

:root {
  /* 银河调色盘 */
  --bg-deep-space: #070913;
  --bg-card-hull: rgba(16, 22, 40, 0.75);
  --bg-card-hover: rgba(26, 35, 64, 0.9);
  --bg-input: rgba(10, 15, 30, 0.85);
  
  /* 列车轨道与霓虹发光色 */
  --rail-cyan: #00e5ff;
  --rail-cyan-glow: rgba(0, 229, 255, 0.35);
  --quantum-purple: #8b5cf6;
  --quantum-purple-glow: rgba(139, 92, 246, 0.3);
  --nebula-pink: #ec4899;
  --signal-amber: #f59e0b;
  --signal-green: #10b981;
  --signal-red: #ef4444;

  /* 文字系统与对比度 (WCAG AA) */
  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --text-inverse: #070913;

  /* 边框与车厢装甲线 */
  --border-hull: rgba(148, 163, 184, 0.15);
  --border-active: rgba(0, 229, 255, 0.5);

  /* 字体家族 */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

  /* 容器与间距 */
  --container-max: 1200px;
  --header-height: 72px;
  --touch-target: 44px;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;
  --transition-normal: 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

/* 全局重置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  background-color: var(--bg-deep-space);
  color: var(--text-main);
  font-family: var(--font-sans);
  line-height: 1.68;
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
}

/* 渐进增强背景：深空星轨背景（纯CSS作为保底，Canvas动态渐进） */
.space-background {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: -1;
  background: 
    radial-gradient(circle at 15% 20%, rgba(139, 92, 246, 0.15) 0%, transparent 45%),
    radial-gradient(circle at 85% 70%, rgba(0, 229, 255, 0.12) 0%, transparent 50%),
    radial-gradient(circle at 50% 90%, rgba(236, 72, 153, 0.08) 0%, transparent 40%),
    #070913;
}

#starfield-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

/* 轨道微光栅格线 */
.rail-grid-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: 
    linear-gradient(to right, rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 60px 60px;
  pointer-events: none;
  z-index: -1;
  opacity: 0.7;
}

/* 链接与排版基石 */
a {
  color: var(--rail-cyan);
  text-decoration: none;
  transition: color var(--transition-normal);
}
a:hover {
  color: #38bdf8;
  text-decoration: underline;
}

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

/* 容器定义 */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 20px;
  padding-right: 20px;
}

/* ==========================================================================
   导航系统 (Galaxy Navigation Header)
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--header-height);
  background: rgba(7, 9, 19, 0.82);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-hull);
  transition: background 0.3s ease;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  text-decoration: none;
  letter-spacing: -0.02em;
}
.brand-logo:hover {
  text-decoration: none;
}
.logo-train-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--rail-cyan), var(--quantum-purple));
  border-radius: var(--radius-sm);
  color: var(--bg-deep-space);
  font-size: 1.1rem;
  box-shadow: 0 0 12px var(--rail-cyan-glow);
}
.brand-title {
  display: flex;
  flex-direction: column;
}
.brand-title-main {
  font-size: 1.15rem;
  line-height: 1.2;
  font-weight: 700;
  background: linear-gradient(90deg, #ffffff, #c7d2fe);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.brand-title-sub {
  font-size: 0.72rem;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 24px;
  list-style: none;
}
.nav-link {
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  transition: all var(--transition-normal);
}
.nav-link:hover, .nav-link.active {
  color: #fff;
  text-decoration: none;
  background: rgba(255, 255, 255, 0.06);
}

.header-cta-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* 手机汉堡按钮 */
.menu-toggle-btn {
  display: none;
  background: transparent;
  border: 1px solid var(--border-hull);
  color: var(--text-main);
  width: var(--touch-target);
  height: var(--touch-target);
  border-radius: var(--radius-sm);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}

/* ==========================================================================
   按钮组件 (CTA Buttons) - 严格遵循统一要求与44px触控尺寸
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: var(--touch-target);
  padding: 10px 22px;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition-normal);
  border: 1px solid transparent;
  line-height: 1.2;
  text-align: center;
}
.btn:hover {
  text-decoration: none;
}

/* 主CTA按钮（银河发光） */
.btn-primary {
  background: linear-gradient(135deg, var(--rail-cyan), #0284c7);
  color: #070913;
  font-weight: 700;
  box-shadow: 0 0 16px var(--rail-cyan-glow);
}
.btn-primary:hover {
  background: linear-gradient(135deg, #38bdf8, #0ea5e9);
  color: #030712;
  box-shadow: 0 0 24px rgba(0, 229, 255, 0.6);
  transform: translateY(-1px);
}

/* 次级按钮 */
.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-main);
  border-color: var(--border-hull);
}
.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--border-active);
  color: #fff;
  transform: translateY(-1px);
}

.btn-sm {
  min-height: 36px;
  padding: 6px 14px;
  font-size: 0.85rem;
  border-radius: var(--radius-sm);
}

/* ==========================================================================
   银河列车 HERO 视觉区域
   ========================================================================== */
.galaxy-hero {
  position: relative;
  padding: 80px 0 60px;
  overflow: hidden;
  border-bottom: 1px solid var(--border-hull);
}

.hero-rail-track {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--rail-cyan), var(--quantum-purple), transparent);
  box-shadow: 0 0 12px var(--rail-cyan-glow);
}

.hero-content {
  max-width: 860px;
  margin: 0 auto;
  text-align: center;
  position: relative;
  z-index: 2;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: rgba(0, 229, 255, 0.1);
  border: 1px solid rgba(0, 229, 255, 0.3);
  border-radius: 9999px;
  color: var(--rail-cyan);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 24px;
  letter-spacing: 0.02em;
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #ffffff 30%, #a5f3fc 70%, #c084fc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 36px;
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 36px;
}

.hero-facts-bar {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  max-width: 780px;
  margin: 40px auto 0;
  padding: 18px 24px;
  background: rgba(16, 22, 40, 0.6);
  border: 1px solid var(--border-hull);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(8px);
}

.fact-item {
  text-align: center;
}
.fact-label {
  font-size: 0.8rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 4px;
}
.fact-value {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--rail-cyan);
}

/* ==========================================================================
   车厢卡片布局 (Galaxy Train Carriages)
   ========================================================================== */
.section {
  padding: 80px 0;
  position: relative;
}
.section-alt {
  background: rgba(10, 14, 28, 0.5);
  border-top: 1px solid var(--border-hull);
  border-bottom: 1px solid var(--border-hull);
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 50px;
}
.section-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--quantum-purple);
  margin-bottom: 10px;
}
.section-title {
  font-size: clamp(1.75rem, 3.5vw, 2.3rem);
  font-weight: 800;
  color: #fff;
  line-height: 1.3;
  margin-bottom: 14px;
}
.section-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* 套餐列车车厢网格 */
.carriage-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  align-items: stretch;
}

.train-carriage-card {
  position: relative;
  background: var(--bg-card-hull);
  border: 1px solid var(--border-hull);
  border-radius: var(--radius-xl);
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  backdrop-filter: blur(10px);
  transition: all var(--transition-normal);
  overflow: hidden;
}
.train-carriage-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-active);
  background: var(--bg-card-hover);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.4), 0 0 20px var(--rail-cyan-glow);
}

.train-carriage-card.featured {
  border-color: var(--rail-cyan);
  background: linear-gradient(180deg, rgba(14, 28, 55, 0.85) 0%, rgba(16, 22, 40, 0.95) 100%);
  box-shadow: 0 0 25px rgba(0, 229, 255, 0.2);
}

.carriage-badge-top {
  position: absolute;
  top: 16px;
  right: 18px;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  background: rgba(0, 229, 255, 0.15);
  color: var(--rail-cyan);
  border: 1px solid rgba(0, 229, 255, 0.3);
  text-transform: uppercase;
}

.carriage-header {
  margin-bottom: 20px;
}
.carriage-number {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 6px;
}
.carriage-name {
  font-size: 1.45rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 8px;
}
.carriage-brief {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.carriage-price-box {
  margin: 16px 0 24px;
  padding: 16px;
  background: rgba(0, 0, 0, 0.3);
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.06);
}
.price-display {
  display: flex;
  align-items: baseline;
  gap: 4px;
}
.price-currency {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--rail-cyan);
}
.price-amount {
  font-size: 2.5rem;
  font-weight: 800;
  color: #fff;
  line-height: 1;
}
.price-period {
  font-size: 0.95rem;
  color: var(--text-muted);
}
.price-note {
  font-size: 0.8rem;
  color: var(--signal-amber);
  margin-top: 6px;
  display: block;
}

.carriage-specs-list {
  list-style: none;
  margin-bottom: 28px;
  flex-grow: 1;
}
.spec-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-main);
  padding: 8px 0;
  border-bottom: 1px dashed rgba(255, 255, 255, 0.07);
}
.spec-item:last-child {
  border-bottom: none;
}
.spec-icon {
  color: var(--rail-cyan);
  font-size: 1rem;
  line-height: 1.4;
  flex-shrink: 0;
}

/* ==========================================================================
   实用功能：银河成本计算器 (Galaxy Fare Calculator)
   ========================================================================== */
.calculator-box {
  background: var(--bg-card-hull);
  border: 1px solid var(--border-hull);
  border-radius: var(--radius-xl);
  padding: 40px;
  max-width: 980px;
  margin: 0 auto;
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(12px);
}

.calc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 36px;
}

.calc-inputs {
  display: flex;
  flex-direction: column;
  gap: 22px;
}

.calc-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.calc-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-main);
  display: flex;
  justify-content: space-between;
}
.calc-label-val {
  color: var(--rail-cyan);
  font-family: var(--font-mono);
}

.calc-slider {
  width: 100%;
  height: 6px;
  border-radius: 3px;
  background: #1e293b;
  outline: none;
  -webkit-appearance: none;
}
.calc-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--rail-cyan);
  cursor: pointer;
  box-shadow: 0 0 10px var(--rail-cyan-glow);
  transition: transform 0.1s;
}
.calc-slider::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}

.calc-select, .calc-input-text {
  width: 100%;
  min-height: var(--touch-target);
  padding: 10px 14px;
  background: var(--bg-input);
  border: 1px solid var(--border-hull);
  border-radius: var(--radius-md);
  color: var(--text-main);
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition-normal);
}
.calc-select:focus, .calc-input-text:focus {
  border-color: var(--rail-cyan);
}

.calc-results {
  background: rgba(7, 10, 20, 0.8);
  border: 1px solid rgba(0, 229, 255, 0.25);
  border-radius: var(--radius-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.result-card-heading {
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.result-metric-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 20px;
}

.result-metric-item {
  padding: 14px;
  background: rgba(255, 255, 255, 0.03);
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.05);
}
.metric-title {
  font-size: 0.78rem;
  color: var(--text-dim);
  margin-bottom: 4px;
}
.metric-val {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--rail-cyan);
  font-family: var(--font-mono);
}

.result-conclusion {
  padding: 16px;
  border-radius: var(--radius-md);
  background: rgba(139, 92, 246, 0.12);
  border: 1px solid rgba(139, 92, 246, 0.3);
  font-size: 0.88rem;
  color: #cbd5e1;
  line-height: 1.6;
}

/* ==========================================================================
   维度车厢：周期与选购限制说明 (Galaxy Dimensions)
   ========================================================================== */
.dimension-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.dim-card {
  background: var(--bg-card-hull);
  border: 1px solid var(--border-hull);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: all var(--transition-normal);
}
.dim-card:hover {
  border-color: var(--border-active);
  transform: translateY(-2px);
}
.dim-carriage-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--rail-cyan);
  background: rgba(0, 229, 255, 0.1);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
}
.dim-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 10px;
}
.dim-desc {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.65;
}

/* ==========================================================================
   文章专栏卡片 (Article Cards)
   ========================================================================== */
.article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.article-card {
  background: var(--bg-card-hull);
  border: 1px solid var(--border-hull);
  border-radius: var(--radius-xl);
  padding: 26px;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-normal);
  text-decoration: none;
}
.article-card:hover {
  text-decoration: none;
  border-color: var(--quantum-purple);
  transform: translateY(-4px);
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.5), 0 0 15px var(--quantum-purple-glow);
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.8rem;
  color: var(--text-dim);
  margin-bottom: 12px;
}
.article-tag {
  color: var(--quantum-purple);
  font-weight: 600;
}
.article-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: #fff;
  line-height: 1.45;
  margin-bottom: 12px;
}
.article-excerpt {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 20px;
  flex-grow: 1;
}
.article-readmore {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--rail-cyan);
}

/* ==========================================================================
   真实评价空态区域 (Honest Empty Testimonials)
   ========================================================================== */
.empty-reviews-box {
  background: rgba(16, 22, 40, 0.5);
  border: 1px dashed var(--border-hull);
  border-radius: var(--radius-xl);
  padding: 48px 32px;
  text-align: center;
  max-width: 820px;
  margin: 0 auto;
}
.empty-icon {
  font-size: 2.4rem;
  color: var(--text-dim);
  margin-bottom: 16px;
}
.empty-reviews-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 10px;
}
.empty-reviews-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.7;
  max-width: 620px;
  margin: 0 auto;
}

/* ==========================================================================
   FAQ 折叠问答系统
   ========================================================================== */
.faq-list {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--bg-card-hull);
  border: 1px solid var(--border-hull);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color var(--transition-normal);
}
.faq-item:hover {
  border-color: rgba(255, 255, 255, 0.25);
}

.faq-question {
  width: 100%;
  min-height: var(--touch-target);
  padding: 20px 24px;
  background: transparent;
  border: none;
  color: #fff;
  font-size: 1.05rem;
  font-weight: 600;
  text-align: left;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  cursor: pointer;
  line-height: 1.4;
}
.faq-toggle-icon {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.05);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  color: var(--rail-cyan);
  flex-shrink: 0;
  transition: transform 0.2s ease;
}
.faq-item.active .faq-toggle-icon {
  transform: rotate(45deg);
  background: var(--rail-cyan);
  color: var(--bg-deep-space);
}

.faq-answer {
  padding: 0 24px 22px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
  display: none;
  border-top: 1px solid rgba(255, 255, 255, 0.04);
  padding-top: 16px;
}
.faq-item.active .faq-answer {
  display: block;
}

/* ==========================================================================
   文章详情页与富文本排版 (Article Layout & Typography)
   ========================================================================== */
.article-header {
  padding: 60px 0 40px;
  border-bottom: 1px solid var(--border-hull);
  background: rgba(10, 14, 28, 0.4);
}
.article-breadcrumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-bottom: 18px;
  flex-wrap: wrap;
}
.article-breadcrumbs a {
  color: var(--text-muted);
}
.article-breadcrumbs a:hover {
  color: var(--rail-cyan);
}
.breadcrumbs-sep {
  color: var(--text-dim);
}

.article-main-title {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 800;
  color: #fff;
  line-height: 1.3;
  margin-bottom: 16px;
}

.article-header-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 0.85rem;
  color: var(--text-muted);
  flex-wrap: wrap;
}

.article-content-body {
  padding: 50px 0 80px;
}
.article-body-wrapper {
  max-width: 820px;
  margin: 0 auto;
}

/* 正文元素排版 */
.prose {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #cbd5e1;
}
.prose p {
  margin-bottom: 1.5rem;
}
.prose h2 {
  font-size: 1.55rem;
  font-weight: 700;
  color: #fff;
  margin: 2.4rem 0 1rem;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-hull);
}
.prose h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: #e2e8f0;
  margin: 1.8rem 0 0.8rem;
}
.prose ul, .prose ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}
.prose li {
  margin-bottom: 0.5rem;
}
.prose strong {
  color: #fff;
}

/* 正文内的实用工具容器：数据比较表、决策树、模板框 */
.prose-table-container {
  width: 100%;
  overflow-x: auto;
  margin: 1.8rem 0;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-hull);
  background: var(--bg-card-hull);
}
.prose-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.92rem;
}
.prose-table th {
  background: rgba(255, 255, 255, 0.05);
  color: #fff;
  font-weight: 600;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-hull);
  white-space: nowrap;
}
.prose-table td {
  padding: 12px 16px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
  color: var(--text-muted);
}
.prose-table tr:last-child td {
  border-bottom: none;
}
.prose-table tr:hover td {
  background: rgba(255, 255, 255, 0.02);
  color: #fff;
}

/* 警示与事实提醒框 */
.callout {
  padding: 20px 22px;
  border-radius: var(--radius-md);
  margin: 1.8rem 0;
  border-left: 4px solid;
}
.callout-info {
  background: rgba(0, 229, 255, 0.08);
  border-left-color: var(--rail-cyan);
  color: #cffafe;
}
.callout-warning {
  background: rgba(245, 158, 11, 0.08);
  border-left-color: var(--signal-amber);
  color: #fef3c7;
}
.callout-title {
  font-weight: 700;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* 文章内的步骤与记录模板卡片 */
.decision-card, .template-card {
  background: rgba(16, 22, 40, 0.7);
  border: 1px solid var(--border-hull);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin: 1.8rem 0;
}
.decision-title, .template-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* 文章结尾行动呼吁 */
.article-footer-cta {
  margin-top: 50px;
  padding: 36px 30px;
  background: linear-gradient(135deg, rgba(16, 22, 40, 0.8), rgba(26, 35, 64, 0.8));
  border: 1px solid var(--border-active);
  border-radius: var(--radius-xl);
  text-align: center;
}
.article-footer-cta h3 {
  font-size: 1.35rem;
  color: #fff;
  margin-bottom: 10px;
}
.article-footer-cta p {
  color: var(--text-muted);
  max-width: 580px;
  margin: 0 auto 20px;
  font-size: 0.95rem;
}

/* ==========================================================================
   页脚系统 (Footer)
   ========================================================================== */
.site-footer {
  margin-top: auto;
  background: #04050b;
  border-top: 1px solid var(--border-hull);
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 50px;
}

.footer-brand p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 12px;
  line-height: 1.65;
  max-width: 360px;
}

.footer-heading {
  font-size: 0.95rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 18px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.footer-link {
  color: var(--text-muted);
  font-size: 0.9rem;
}
.footer-link:hover {
  color: var(--rail-cyan);
}

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-dim);
  flex-wrap: wrap;
  gap: 16px;
}

/* ==========================================================================
   响应式断点 (360px, 390px, 430px, 768px, 1024px, 1440px)
   ========================================================================== */
@media (max-width: 1024px) {
  .carriage-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .article-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }
  
  .menu-toggle-btn {
    display: inline-flex;
  }
  
  .nav-menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    background: rgba(7, 9, 19, 0.96);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    flex-direction: column;
    padding: 24px;
    gap: 12px;
    border-bottom: 1px solid var(--border-hull);
    display: none;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.8);
  }
  .nav-menu.open {
    display: flex;
  }
  .nav-link {
    width: 100%;
    min-height: var(--touch-target);
    display: flex;
    align-items: center;
    padding: 10px 16px;
    font-size: 1rem;
  }

  .carriage-grid,
  .dimension-cards,
  .article-grid,
  .calc-grid,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .hero-facts-bar {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .hero-actions {
    flex-direction: column;
    width: 100%;
  }
  .hero-actions .btn {
    width: 100%;
  }

  .calculator-box {
    padding: 24px 18px;
  }

  .train-carriage-card {
    padding: 24px 20px;
  }
}

/* 极小屏幕微调 (360px - 430px) */
@media (max-width: 430px) {
  .container {
    padding-left: 16px;
    padding-right: 16px;
  }
  .price-amount {
    font-size: 2.1rem;
  }
  .result-metric-grid {
    grid-template-columns: 1fr;
  }
}

/* 无障碍：减少动效模式 */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}