/* ==========================================================================
   NaNoCloud 【风格 05 · 芯片云脑】PCB 电路板风 核心样式表
   配色：深墨绿黑 #0D1512 | 电路金 #F5B942 | 铜橙 #E2874B | 米白 #EAEFEB
   ========================================================================== */

:root {
  --bg-pcb: #0D1512;
  --bg-card: #131E1A;
  --bg-card-hover: #182822;
  --bg-card-header: #101915;
  --border-pcb: rgba(245, 185, 66, 0.16);
  --border-copper: rgba(226, 135, 75, 0.22);
  --border-active: #F5B942;

  --gold: #F5B942;
  --gold-dim: rgba(245, 185, 66, 0.12);
  --gold-glow: 0 0 20px rgba(245, 185, 66, 0.35);
  --copper: #E2874B;
  --copper-dim: rgba(226, 135, 75, 0.15);

  --text-main: #EAEFEB;
  --text-sub: #92A69B;
  --text-dim: #657A70;

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-full: 9999px;

  --font-title: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", -apple-system, sans-serif;
  --font-num: "Space Grotesk", "Consolas", "Courier New", monospace, sans-serif;
  --container-max: 1200px;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-title);
  background-color: var(--bg-pcb);
  color: var(--text-main);
  line-height: 1.6;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  background: var(--bg-pcb);
  position: relative;
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* 顶部导航栏 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13, 21, 18, 0.88);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-pcb);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.35rem;
  font-weight: 900;
  letter-spacing: -0.5px;
  color: var(--text-main);
}

.logo-symbol {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, #1A2E26 0%, #101D17 100%);
  border: 1.5px solid var(--gold);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 12px rgba(245, 185, 66, 0.3);
  position: relative;
}

.logo-symbol svg {
  width: 20px;
  height: 20px;
  fill: var(--gold);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-link {
  font-size: 0.95rem;
  color: var(--text-sub);
  font-weight: 500;
  transition: color 0.2s ease;
}

.nav-link:hover {
  color: var(--gold);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

/* 按钮规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 24px;
  font-size: 0.95rem;
  font-weight: 700;
  border-radius: var(--radius-sm);
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  cursor: pointer;
  border: 1px solid transparent;
  white-space: nowrap;
  text-align: center;
  position: relative;
}

.btn-primary {
  background: linear-gradient(135deg, #F5B942 0%, #E2874B 100%);
  color: #0D1512;
  box-shadow: 0 4px 18px rgba(245, 185, 66, 0.3);
  font-weight: 800;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 26px rgba(245, 185, 66, 0.55);
  filter: brightness(1.05);
}

.btn-secondary {
  background: rgba(19, 30, 26, 0.85);
  color: var(--text-main);
  border-color: var(--border-pcb);
}

.btn-secondary:hover {
  background: rgba(24, 40, 34, 0.95);
  border-color: var(--gold);
  color: var(--gold);
  transform: translateY(-2px);
}

.btn-lg {
  padding: 14px 34px;
  font-size: 1.05rem;
}

.btn-block {
  width: 100%;
}

/* 子页面头部与内容区 */
.page-hero {
  padding: 60px 0 40px;
  border-bottom: 1px solid var(--border-pcb);
  background: rgba(19, 30, 26, 0.5);
}

.page-title {
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 900;
  color: #FFFFFF;
  margin-bottom: 12px;
}

.page-subtitle {
  font-size: 1.05rem;
  color: var(--text-sub);
}

.article-content {
  padding: 50px 0 80px;
  max-width: 860px;
  margin: 0 auto;
}

.article-section {
  margin-bottom: 40px;
}

.article-section h2 {
  font-size: 1.45rem;
  color: #FFFFFF;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-pcb);
  display: flex;
  align-items: center;
  gap: 10px;
}

.article-section p {
  color: var(--text-sub);
  font-size: 0.98rem;
  line-height: 1.8;
  margin-bottom: 14px;
}

.article-section ul {
  padding-left: 20px;
  color: var(--text-sub);
  font-size: 0.98rem;
  line-height: 1.8;
  margin-bottom: 16px;
}

.article-section li {
  margin-bottom: 8px;
}

/* 文章内嵌 FAQ 折叠样式 */
.faq-container {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 20px 0 32px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-pcb);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: all 0.2s ease;
}

.faq-item[open] {
  border-color: var(--gold);
  background: var(--bg-card-hover);
}

.faq-question {
  padding: 16px 20px;
  font-size: 1rem;
  font-weight: 700;
  color: #FFFFFF;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
}

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

.faq-icon {
  width: 18px;
  height: 18px;
  fill: var(--gold);
  transition: transform 0.25s ease;
  flex-shrink: 0;
  margin-left: 12px;
}

.faq-item[open] .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 20px 18px;
  font-size: 0.94rem;
  color: var(--text-sub);
  line-height: 1.75;
}

/* 相关推荐文章内链卡片 */
.related-box {
  margin: 40px 0 20px;
  padding: 24px;
  background: rgba(19, 30, 26, 0.6);
  border: 1px solid var(--border-pcb);
  border-radius: var(--radius-md);
}

.related-box h3 {
  font-size: 1.15rem;
  color: var(--gold);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.related-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 12px;
  padding-left: 0 !important;
}

.related-list li {
  margin-bottom: 0 !important;
}

.related-link-item {
  display: block;
  padding: 12px 16px;
  background: var(--bg-card);
  border: 1px solid rgba(245, 185, 66, 0.12);
  border-radius: 6px;
  color: var(--text-main);
  font-size: 0.9rem;
  transition: all 0.2s ease;
}

.related-link-item:hover {
  border-color: var(--gold);
  color: var(--gold);
  transform: translateX(4px);
}

.back-to-home {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--gold);
  font-size: 0.92rem;
  font-weight: 700;
  margin-bottom: 24px;
  transition: transform 0.2s ease;
}

.back-to-home:hover {
  transform: translateX(-4px);
  color: #F8D179;
}

/* 页尾 Footer (严格仅保留 4 个独立链接) */
.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--border-pcb);
  background: #090F0C;
  padding: 45px 0 35px;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 36px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.footer-link {
  font-size: 0.95rem;
  color: var(--text-sub);
  transition: color 0.2s ease;
  font-weight: 600;
}

.footer-link:hover {
  color: var(--gold);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.footer-copy {
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-dim);
  font-family: var(--font-num);
}

@media (max-width: 768px) {
  .nav-menu {
    display: none;
  }
  .footer-nav {
    flex-direction: column;
    gap: 16px;
  }
  .btn {
    min-height: 48px;
    font-size: 1rem;
  }
  .footer-link, .nav-link, .faq-question {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
  }
}

/* ==========================================================================
   无障碍 (Accessibility) 与交互规范增强
   ========================================================================== */
.skip-link {
  position: absolute;
  top: -120px;
  left: 20px;
  background: var(--gold);
  color: #0D1512;
  padding: 10px 20px;
  font-weight: 800;
  border-radius: var(--radius-sm);
  z-index: 999999;
  text-decoration: none;
  transition: top 0.2s ease;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
}

.skip-link:focus {
  top: 16px;
  outline: 3px solid #FFFFFF;
}

:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 3px;
}

section[id], div[id], article[id], main[id] {
  scroll-margin-top: 84px;
}

p, h1, h2, h3, h4, li, summary, td, th {
  overflow-wrap: break-word;
  word-break: break-word;
}

@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;
  }
}