/* ==========================================================================
   nice cloud - 电影级聚光舞台 (Cinematic Spotlight Stage) 样式系统
   规范：移动端优先，支持 320px, 375px, 390px, 768px, 1024px
   ========================================================================== */

:root {
  /* 舞台色彩体系 */
  --bg-stage-deep: #06070a;
  --bg-stage: #0a0b12;
  --bg-surface: rgba(16, 18, 30, 0.78);
  --bg-surface-elevated: rgba(24, 27, 44, 0.9);
  --bg-surface-active: rgba(34, 38, 62, 0.95);
  --bg-glass: rgba(14, 16, 26, 0.65);

  /* 电影聚光灯色彩与光源 */
  --spotlight-beam-1: rgba(56, 189, 248, 0.16);
  --spotlight-beam-2: rgba(129, 140, 248, 0.12);
  --spotlight-beam-amber: rgba(251, 191, 36, 0.12);
  --glow-cyan: #38bdf8;
  --glow-violet: #818cf8;
  --glow-amber: #fbbf24;
  --glow-rose: #f43f5e;
  --glow-emerald: #10b981;

  /* 文字体系 */
  --text-main: #f8fafc;
  --text-primary: #e2e8f0;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-dark: #334155;

  /* 边框与聚光投影 */
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-stage: rgba(56, 189, 248, 0.22);
  --border-focus: rgba(129, 140, 248, 0.45);
  --shadow-stage: 0 20px 50px rgba(0, 0, 0, 0.6), 0 0 40px rgba(56, 189, 248, 0.05);
  --shadow-spotlight: 0 10px 30px -5px rgba(56, 189, 248, 0.25);

  /* 尺寸与圆角 */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  --container-max: 1140px;

  /* 动效 */
  --transition-fast: 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-smooth: 0.35s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-cinematic: 0.6s cubic-bezier(0.16, 1, 0.3, 1);

  /* 聚光灯动态坐标默认值 */
  --spotlight-x: 50%;
  --spotlight-y: 20%;
}

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

html {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text-primary);
  background-color: var(--bg-stage-deep);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  position: relative;
  min-height: 100vh;
  background-color: var(--bg-stage);
  background-image: 
    radial-gradient(ellipse 80% 50% at 50% -10%, rgba(56, 189, 248, 0.14), transparent 70%),
    radial-gradient(ellipse 60% 40% at 90% 40%, rgba(129, 140, 248, 0.08), transparent 60%),
    radial-gradient(ellipse 50% 30% at 10% 80%, rgba(251, 191, 36, 0.05), transparent 50%);
  background-attachment: fixed;
  overflow-x: hidden;
  color: var(--text-primary);
}

/* 电影聚光舞台全局光照层 */
.stage-spotlight-layer {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  background: radial-gradient(circle 650px at var(--spotlight-x) var(--spotlight-y), rgba(56, 189, 248, 0.08), transparent 75%);
  transition: opacity var(--transition-fast);
}

/* 顶部微细光带（剧场天花板光柱） */
.theatrical-stage-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, #38bdf8 25%, #818cf8 50%, #c084fc 75%, transparent);
  z-index: 100;
  opacity: 0.85;
}

/* 容器定义 */
.stage-container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.25rem;
  padding-right: 1.25rem;
}

/* 排版与强对比大标题 */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(1.85rem, 5vw, 3.25rem);
  font-weight: 900;
  margin-bottom: 1.25rem;
}

h2 {
  font-size: clamp(1.4rem, 3.5vw, 2.1rem);
  margin-top: 2rem;
  margin-bottom: 1rem;
  position: relative;
}

h3 {
  font-size: clamp(1.15rem, 2.5vw, 1.45rem);
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
}

p {
  margin-bottom: 1rem;
  color: var(--text-primary);
}

a {
  color: var(--glow-cyan);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: #7dd3fc;
  text-decoration: underline;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  background: rgba(255, 255, 255, 0.08);
  color: #38bdf8;
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.9em;
}

pre {
  background: rgba(10, 12, 20, 0.95);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  overflow-x: auto;
  margin: 1.25rem 0;
  color: #e2e8f0;
}

pre code {
  background: transparent;
  padding: 0;
  color: inherit;
}

/* 导航栏设计 */
.stage-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(10, 11, 18, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  transition: all var(--transition-smooth);
}

.stage-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
}

.brand-logo-img {
  height: 40px;
  width: auto;
  display: block;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.nav-link {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  transition: color var(--transition-fast);
  padding: 0.5rem 0.25rem;
  position: relative;
}

.nav-link:hover, .nav-link.active {
  color: #ffffff;
  text-decoration: none;
}

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--glow-cyan);
  border-radius: 2px;
  box-shadow: 0 0 10px var(--glow-cyan);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* 汉堡按钮 */
.menu-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-main);
  padding: 0.5rem 0.65rem;
  cursor: pointer;
  font-size: 1.25rem;
  transition: background var(--transition-fast);
}

.menu-toggle:hover {
  background: rgba(255, 255, 255, 0.08);
}

/* 官方主 CTA 按钮系统（聚光亮色按钮） */
.btn-spotlight {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 0.75rem 1.65rem;
  font-size: 1rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  color: #07080f;
  background: linear-gradient(135deg, #38bdf8 0%, #60a5fa 50%, #c084fc 100%);
  border: none;
  text-decoration: none;
  cursor: pointer;
  box-shadow: 0 4px 20px rgba(56, 189, 248, 0.35);
  transition: all var(--transition-smooth);
  position: relative;
  overflow: hidden;
  white-space: nowrap;
}

.btn-spotlight::before {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
  transition: left 0.6s ease;
}

.btn-spotlight:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(56, 189, 248, 0.55);
  color: #04050a;
  text-decoration: none;
}

.btn-spotlight:hover::before {
  left: 100%;
}

.btn-stage-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.4rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-stage-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--border-stage);
  color: #ffffff;
  text-decoration: none;
}

.btn-sm {
  padding: 0.45rem 1.1rem;
  font-size: 0.88rem;
}

/* 舞台聚光卡片系统 */
.spotlight-card {
  position: relative;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: var(--shadow-stage);
  transition: all var(--transition-smooth);
  overflow: hidden;
}

.spotlight-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(56, 189, 248, 0.35), transparent);
  opacity: 0.6;
}

.spotlight-card:hover {
  border-color: var(--border-stage);
  transform: translateY(-3px);
  box-shadow: 0 15px 40px rgba(0, 0, 0, 0.7), 0 0 25px rgba(56, 189, 248, 0.15);
}

/* 舞台徽标标签 */
.stage-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.3rem 0.85rem;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border-radius: var(--radius-full);
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.3);
  color: #7dd3fc;
  margin-bottom: 1rem;
}

.stage-badge.amber {
  background: rgba(251, 191, 36, 0.1);
  border-color: rgba(251, 191, 36, 0.3);
  color: #fde047;
}

.stage-badge.emerald {
  background: rgba(16, 185, 129, 0.1);
  border-color: rgba(16, 185, 129, 0.3);
  color: #6ee7b7;
}

.stage-badge.violet {
  background: rgba(129, 140, 248, 0.1);
  border-color: rgba(129, 140, 248, 0.3);
  color: #a5b4fc;
}

/* Hero 剧场展台 */
.hero-stage {
  position: relative;
  padding: 4.5rem 0 3.5rem;
  text-align: center;
}

.hero-stage-content {
  max-width: 840px;
  margin: 0 auto;
}

.hero-subtitle {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 2rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  margin-bottom: 2.5rem;
}

.hero-fact-notice {
  font-size: 0.85rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

/* 剧场聚光焦点展示板 */
.theatrical-podium {
  position: relative;
  margin: 2.5rem auto 0;
  padding: 2rem;
  background: radial-gradient(ellipse at 50% -20%, rgba(56, 189, 248, 0.18), rgba(16, 18, 30, 0.95) 70%);
  border: 1px solid var(--border-stage);
  border-radius: var(--radius-lg);
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.8), 0 0 50px rgba(56, 189, 248, 0.1);
}

.podium-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.25rem;
  text-align: left;
}

.podium-item {
  padding: 1.25rem;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.podium-item:hover {
  background: rgba(56, 189, 248, 0.05);
  border-color: rgba(56, 189, 248, 0.2);
}

.podium-metric {
  font-size: 1.6rem;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 0.25rem;
}

.podium-metric span {
  font-size: 0.9rem;
  color: var(--glow-cyan);
  margin-left: 0.2rem;
}

.podium-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* 核心板块间距 */
.stage-section {
  padding: 4rem 0;
  position: relative;
}

.section-head {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 3rem;
}

.section-head p {
  color: var(--text-secondary);
  font-size: 1.05rem;
}

/* 网格布局 */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.75rem;
}

/* 文章卡片 */
.article-card {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.article-card-header {
  margin-bottom: 1rem;
}

.article-card-meta {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 0.6rem;
}

.article-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 0.75rem;
}

.article-card-title a {
  color: #ffffff;
  text-decoration: none;
}

.article-card-title a:hover {
  color: var(--glow-cyan);
}

.article-card-excerpt {
  color: var(--text-secondary);
  font-size: 0.92rem;
  line-height: 1.6;
  flex-grow: 1;
  margin-bottom: 1.25rem;
}

.article-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1rem;
  border-top: 1px solid var(--border-subtle);
  font-size: 0.88rem;
}

/* GEO 内容风格：直接问答提示框 */
.geo-answer-box {
  background: linear-gradient(135deg, rgba(56, 189, 248, 0.08), rgba(129, 140, 248, 0.03));
  border-left: 4px solid var(--glow-cyan);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 1.25rem 1.5rem;
  margin-bottom: 1.75rem;
}

.geo-answer-box strong {
  color: #ffffff;
}

/* 结构化对比表格 */
.table-stage-wrapper {
  overflow-x: auto;
  margin: 1.5rem 0;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  background: var(--bg-surface);
}

.stage-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.92rem;
}

.stage-table th {
  background: rgba(255, 255, 255, 0.04);
  color: #ffffff;
  padding: 0.9rem 1.1rem;
  font-weight: 700;
  border-bottom: 1px solid var(--border-subtle);
}

.stage-table td {
  padding: 0.85rem 1.1rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
  color: var(--text-primary);
}

.stage-table tr:hover td {
  background: rgba(56, 189, 248, 0.03);
}

/* 文章详情页样式 */
.article-header {
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 2.5rem;
}

.article-meta-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1.25rem;
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-top: 1.25rem;
}

.article-layout {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 2.5rem;
  align-items: start;
}

@media (max-width: 991px) {
  .article-layout {
    grid-template-columns: 1fr;
  }
}

.article-content {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #cbd5e1;
}

.article-content h2 {
  font-size: 1.6rem;
  color: #ffffff;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.article-content h3 {
  font-size: 1.25rem;
  color: #f1f5f9;
  margin-top: 1.75rem;
  margin-bottom: 0.75rem;
}

.article-content ul, .article-content ol {
  margin: 1rem 0 1.5rem 1.5rem;
}

.article-content li {
  margin-bottom: 0.5rem;
}

.article-toc-sticky {
  position: sticky;
  top: 90px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  max-height: calc(100vh - 120px);
  overflow-y: auto;
}

.article-toc-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.article-toc-list {
  list-style: none;
  font-size: 0.88rem;
}

.article-toc-list li {
  margin-bottom: 0.5rem;
}

.article-toc-list a {
  color: var(--text-secondary);
  display: block;
  transition: color var(--transition-fast);
}

.article-toc-list a:hover, .article-toc-list a.active {
  color: var(--glow-cyan);
  padding-left: 4px;
}

/* 面包屑 */
.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.breadcrumbs a {
  color: var(--text-secondary);
}

.breadcrumbs a:hover {
  color: var(--glow-cyan);
}

/* FAQ 交互折叠板 */
.faq-stage-group {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq-card:hover {
  border-color: var(--border-stage);
}

.faq-card summary {
  padding: 1.25rem 1.5rem;
  font-weight: 700;
  font-size: 1.05rem;
  color: #ffffff;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  list-style: none;
}

.faq-card summary::-webkit-details-marker {
  display: none;
}

.faq-card summary::after {
  content: "+";
  font-size: 1.35rem;
  color: var(--glow-cyan);
  transition: transform var(--transition-smooth);
}

.faq-card[open] summary::after {
  transform: rotate(45deg);
}

.faq-card .faq-answer {
  padding: 0 1.5rem 1.25rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
  border-top: 1px solid rgba(255, 255, 255, 0.04);
}

/* 官方入口卡片（Stage Banner） */
.official-cta-stage {
  position: relative;
  background: radial-gradient(ellipse at 50% 0%, rgba(56, 189, 248, 0.22), rgba(13, 14, 24, 0.95) 75%);
  border: 1px solid var(--border-stage);
  border-radius: var(--radius-lg);
  padding: 3rem 2rem;
  text-align: center;
  margin: 3.5rem 0;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.7);
}

.official-cta-stage h2 {
  margin-top: 0;
  font-size: clamp(1.6rem, 3vw, 2.25rem);
}

.official-cta-stage p {
  color: var(--text-secondary);
  max-width: 650px;
  margin: 0 auto 1.75rem;
  font-size: 1.02rem;
}

/* 用户反馈表单与体验区（拒绝虚假好评） */
.feedback-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin: 2.5rem 0;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-label {
  display: block;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.form-control {
  width: 100%;
  padding: 0.75rem 1rem;
  background: rgba(10, 12, 20, 0.8);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: #ffffff;
  font-size: 0.95rem;
  transition: border-color var(--transition-fast);
}

.form-control:focus {
  outline: none;
  border-color: var(--glow-cyan);
  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.15);
}

textarea.form-control {
  min-height: 120px;
  resize: vertical;
}

/* 页脚系统 */
.stage-footer {
  background: #050609;
  border-top: 1px solid var(--border-subtle);
  padding: 4rem 0 2.5rem;
  margin-top: 5rem;
  color: var(--text-secondary);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 3rem;
}

.footer-brand p {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-top: 1rem;
  max-width: 340px;
}

.footer-title {
  color: #ffffff;
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 1.25rem;
  letter-spacing: 0.02em;
}

.footer-links {
  list-style: none;
  font-size: 0.88rem;
}

.footer-links li {
  margin-bottom: 0.65rem;
}

.footer-links a {
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.footer-links a:hover {
  color: #ffffff;
  text-decoration: none;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  font-size: 0.82rem;
  color: var(--text-muted);
}

.footer-statement {
  max-width: 650px;
  line-height: 1.5;
}

/* 响应式断点适配：320px, 375px, 390px, 768px, 1024px */
@media (max-width: 1024px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }
}

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav-menu {
    position: fixed;
    top: 68px;
    left: 0;
    right: 0;
    background: rgba(10, 12, 20, 0.98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-subtle);
    flex-direction: column;
    padding: 1.5rem 1.25rem;
    gap: 1rem;
    align-items: flex-start;
    transform: translateY(-150%);
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition-smooth);
    z-index: 49;
  }

  .nav-menu.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-link {
    font-size: 1.05rem;
    width: 100%;
    padding: 0.65rem 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.04);
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .podium-grid {
    grid-template-columns: 1fr;
  }

  .hero-stage {
    padding: 3rem 0 2rem;
  }
}

@media (max-width: 390px) {
  .stage-container {
    padding-left: 1rem;
    padding-right: 1rem;
  }

  .brand-logo-img {
    height: 34px;
  }

  .btn-spotlight {
    width: 100%;
    padding: 0.75rem 1.25rem;
    font-size: 0.95rem;
  }

  .btn-stage-secondary {
    width: 100%;
  }

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

@media (max-width: 320px) {
  html {
    font-size: 15px;
  }

  .spotlight-card {
    padding: 1.25rem;
  }
}

/* 交互测试小工具（学习用延迟丢包计算器 - 不编造虚假测速） */
.diagnostic-sandbox {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-stage);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  margin: 2rem 0;
}

.sandbox-row {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.sandbox-output {
  background: rgba(0, 0, 0, 0.4);
  border-radius: var(--radius-sm);
  padding: 1rem;
  font-family: monospace;
  font-size: 0.9rem;
  color: #38bdf8;
  white-space: pre-wrap;
}