/* ==========================================================
   /assets/site.css — 易倍入口 全站共享样式
   设计体系：深蓝框架 + 荧光绿数据强调 + 暖纸底色
   版本：1.0.0
   ========================================================== */

/* ---------- CSS 变量（全局 :root 命名空间） ---------- */
:root {
  --color-primary: #0a2540;
  --color-primary-soft: #3d5a80;
  --color-accent: #c6ff00;
  --color-accent-alt: #00e676;
  --color-bg: #f5efe6;
  --color-ink: #1a1a1a;
  --color-muted: #8c8c8c;
  --color-white: #ffffff;
  --font-display: "Noto Serif SC", "Songti SC", "SimSun", serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-data: "JetBrains Mono", "SFMono-Regular", Consolas, monospace;
  --border-width: 3px;
  --shadow-hard: 8px 8px 0 rgba(10, 37, 64, 0.15);
  --radius: 0;
  --section-space: clamp(4rem, 8vw, 7rem);
}

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

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

body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-ink);
  line-height: 1.75;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

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

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

ul,
ol {
  list-style: none;
}

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

:focus-visible {
  outline: 3px solid #c6ff00;
  outline-offset: 3px;
}

::selection {
  background: #c6ff00;
  color: #0a2540;
}

/* ---------- 页面命名空间容器 ---------- */
.page-shell {
  background: var(--color-bg);
  color: var(--color-ink);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ---------- 通用容器与主体 ---------- */
.site-main {
  flex: 1;
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 3rem 1.25rem 5rem;
}

/* ---------- 跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: 0.75rem;
  left: 0.75rem;
  z-index: 3000;
  background: #0a2540;
  color: #ffffff;
  padding: 0.6rem 1.2rem;
  font-weight: 700;
  transform: translateY(-150%);
  transition: transform 0.2s ease;
}

.skip-link:focus-visible {
  transform: translateY(0);
}

/* ---------- 滚动进度条 ---------- */
.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 2500;
  height: 4px;
  width: 0%;
  background: #c6ff00;
  box-shadow: 0 0 12px rgba(198, 255, 0, 0.6);
  transition: width 0.1s linear;
}

@media (prefers-reduced-motion: reduce) {
  .progress-bar {
    display: none;
  }
}

/* ---------- Header ---------- */
.site-header {
  background: #0a2540;
  color: #ffffff;
  border-bottom: 4px solid #c6ff00;
  position: relative;
  z-index: 1000;
}

.header-inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
  min-height: 84px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.875rem;
  color: #ffffff;
}

.brand-logo {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
}

.brand-mark {
  display: inline-block;
  width: 22px;
  height: 22px;
  background: #c6ff00;
  border: 2px solid #ffffff;
  transform: rotate(45deg);
  flex-shrink: 0;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 1.45rem;
  font-weight: 900;
  letter-spacing: 0.05em;
  color: #ffffff;
}

.brand-tagline {
  font-size: 0.8rem;
  color: #8c8c8c;
  letter-spacing: 0.04em;
  border-left: 1px solid rgba(255, 255, 255, 0.2);
  padding-left: 0.875rem;
  display: none;
}

/* ---------- 导航 ---------- */
.site-nav {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  flex-wrap: wrap;
}

.nav-link {
  display: inline-block;
  padding: 0.375rem 0.625rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.78);
  border-left: 3px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.nav-link:hover,
.nav-link:focus-visible {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.08);
  border-left-color: #c6ff00;
}

.nav-link[aria-current="page"] {
  color: #ffffff;
  border-left-color: #c6ff00;
  background: rgba(198, 255, 0, 0.1);
}

.header-cta {
  margin-left: 0.75rem;
}

/* ---------- 移动导航按钮 ---------- */
.mobile-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  background: transparent;
  border: 2px solid rgba(255, 255, 255, 0.4);
  transition: border-color 0.2s ease;
}

.mobile-toggle .toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  background: #ffffff;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.mobile-toggle:hover,
.mobile-toggle:focus-visible {
  border-color: #c6ff00;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  font-weight: 700;
  font-family: var(--font-body);
  font-size: 0.95rem;
  line-height: 1.2;
  border: 3px solid transparent;
  transform: translate(0, 0);
  box-shadow: 0 0 0 rgba(0, 0, 0, 0);
  transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease, color 0.18s ease;
  text-align: center;
}

.btn--primary {
  background: #c6ff00;
  color: #0a2540;
  border-color: #c6ff00;
}

.btn--primary:hover,
.btn--primary:focus-visible {
  transform: translate(3px, 3px);
  box-shadow: 4px 4px 0 rgba(255, 255, 255, 0.3);
}

.btn--ghost {
  background: transparent;
  color: #0a2540;
  border-color: #0a2540;
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  background: #0a2540;
  color: #ffffff;
  transform: translate(3px, 3px);
  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.2);
}

/* ---------- Footer ---------- */
.site-footer {
  background: #0a2540;
  color: #ffffff;
  border-top: 4px solid #c6ff00;
  position: relative;
  z-index: 1000;
}

.footer-inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 3rem 1.25rem 2rem;
  display: grid;
  grid-template-columns: 1.4fr 1fr 1.2fr;
  gap: 2.5rem 2rem;
}

.footer-logo {
  color: #ffffff;
  margin-bottom: 1rem;
}

.footer-tagline {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.6);
  margin-bottom: 0.75rem;
}

.trust-statement {
  font-size: 0.82rem;
  line-height: 1.6;
  color: #8c8c8c;
  border-left: 3px solid #c6ff00;
  padding-left: 0.875rem;
  max-width: 34ch;
}

.footer-heading {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  color: #c6ff00;
  letter-spacing: 0.08em;
  margin-bottom: 1.1rem;
  text-transform: uppercase;
  position: relative;
  padding-left: 0.75rem;
}

.footer-heading::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.15em;
  width: 4px;
  height: 1em;
  background: #c6ff00;
}

.footer-nav-list,
.footer-meta-list {
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.footer-nav-list .nav-link,
.footer-meta-list .nav-link,
.footer-meta-list a,
.footer-meta-list li {
  color: rgba(255, 255, 255, 0.75);
  font-size: 0.9rem;
}

.footer-nav-list .nav-link:hover,
.footer-meta-list a:hover {
  color: #c6ff00;
}

.footer-meta-list li {
  line-height: 1.5;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding: 1.25rem 0;
  background: rgba(0, 0, 0, 0.15);
}

.footer-bottom-inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 1.25rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
}

.copyright {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.6);
}

.icp-link {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.6);
  transition: color 0.2s ease;
}

.icp-link:hover {
  color: #c6ff00;
}

/* ---------- 章节编号 ---------- */
.section-number {
  font-family: var(--font-display);
  font-size: clamp(3rem, 7vw, 5rem);
  line-height: 1;
  font-weight: 900;
  color: #0a2540;
  -webkit-text-stroke: 2px rgba(10, 37, 64, 0.25);
  user-select: none;
}

/* ---------- 滚动显现 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s cubic-bezier(0.22, 1, 0.36, 1), transform 0.7s cubic-bezier(0.22, 1, 0.36, 1);
  will-change: opacity, transform;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* 错峰子元素 */
.reveal-item {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.5s ease, transform 0.5s ease;
  transition-delay: var(--delay, 0ms);
}

.is-visible .reveal-item {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  .reveal,
  .reveal-item {
    opacity: 1;
    transform: none;
    transition: none;
  }

  html {
    scroll-behavior: auto;
  }
}

/* ---------- 图片框架 ---------- */
.img-frame {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #0a2540 0%, #3d5a80 100%);
  border: 3px solid #0a2540;
  box-shadow: var(--shadow-hard);
  aspect-ratio: 4 / 3;
}

.img-frame--wide {
  aspect-ratio: 16 / 10;
}

.img-frame--tall {
  aspect-ratio: 3 / 4;
}

.img-frame::before {
  content: attr(data-caption);
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 0.5rem 0.75rem;
  background: rgba(10, 37, 64, 0.82);
  color: #ffffff;
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  font-family: var(--font-body);
  opacity: 0;
  transform: translateY(100%);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

.img-frame:hover::before,
.img-frame:focus-within::before {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- 文本容器 ---------- */
.prose {
  max-width: 68ch;
  line-height: 1.85;
}

.prose p + p {
  margin-top: 1.25em;
}

.prose h1,
.prose h2,
.prose h3 {
  font-family: var(--font-display);
  font-weight: 900;
  line-height: 1.25;
  margin-bottom: 0.6em;
  margin-top: 1.6em;
}

.prose h1 {
  font-size: clamp(2.2rem, 5vw, 3.25rem);
}

.prose h2 {
  font-size: clamp(1.5rem, 3vw, 2rem);
}

/* ---------- 网格通用 ---------- */
.grid {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(12, 1fr);
}

.grid .span-3 { grid-column: span 3; }
.grid .span-4 { grid-column: span 4; }
.grid .span-6 { grid-column: span 6; }
.grid .span-8 { grid-column: span 8; }
.grid .span-12 { grid-column: span 12; }

/* ---------- 数据标签 ---------- */
.data-chip {
  font-family: var(--font-data);
  font-size: 0.9rem;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.2rem 0.625rem;
  background: rgba(198, 255, 0, 0.08);
  border: 2px solid #c6ff00;
  color: #0a2540;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  border: 3px solid #0a2540;
  background: #ffffff;
  padding: 0.625rem 1rem;
  box-shadow: 4px 4px 0 rgba(10, 37, 64, 0.1);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  margin-bottom: 2rem;
}

.breadcrumb a {
  color: #0a2540;
  font-weight: 600;
  transition: color 0.2s ease;
}

.breadcrumb a:hover {
  color: #3d5a80;
}

.breadcrumb span {
  color: #8c8c8c;
}

/* ---------- 返回顶部 ---------- */
.top-link {
  position: fixed;
  bottom: 1.25rem;
  right: 1.25rem;
  z-index: 2000;
  background: #0a2540;
  color: #c6ff00;
  border: 2px solid #c6ff00;
  width: 46px;
  height: 46px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  font-weight: 900;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s, background 0.2s ease;
  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.2);
}

.top-link.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.top-link:hover,
.top-link:focus-visible {
  background: #c6ff00;
  color: #0a2540;
}

@media (prefers-reduced-motion: reduce) {
  .top-link {
    transition: none;
  }
}

/* ---------- 响应式 ---------- */
@media (max-width: 960px) {
  .header-inner {
    flex-wrap: nowrap;
  }

  .brand-tagline {
    display: none;
  }

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

  .grid .span-3,
  .grid .span-4,
  .grid .span-6,
  .grid .span-8 {
    grid-column: span 6;
  }
}

@media (max-width: 768px) {
  .header-inner {
    min-height: 68px;
    padding: 0.625rem 1rem;
  }

  .brand-name {
    font-size: 1.2rem;
  }

  .mobile-toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: min(88vw, 360px);
    background: #0a2540;
    flex-direction: column;
    justify-content: flex-start;
    align-items: stretch;
    padding: 5.5rem 1.5rem 2rem;
    box-shadow: -8px 0 30px rgba(0, 0, 0, 0.35);
    transform: translateX(100%);
    visibility: hidden;
    transition: transform 0.3s cubic-bezier(0.22, 1, 0.36, 1), visibility 0s linear 0.3s;
    gap: 2rem;
    overflow-y: auto;
    z-index: 1500;
  }

  .site-nav[data-open="true"] {
    transform: translateX(0);
    visibility: visible;
    transition: transform 0.3s cubic-bezier(0.22, 1, 0.36, 1), visibility 0s linear 0s;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0.15rem;
  }

  .nav-link {
    display: block;
    padding: 0.75rem 0.5rem;
    font-size: 1.1rem;
    border-left: 3px solid transparent;
  }

  .nav-link[aria-current="page"] {
    border-left-color: #c6ff00;
  }

  .header-cta {
    margin: 0;
    justify-content: center;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    padding: 2rem 1rem 1.5rem;
    gap: 2rem;
  }

  .footer-bottom-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .grid .span-3,
  .grid .span-4,
  .grid .span-6,
  .grid .span-8,
  .grid .span-12 {
    grid-column: span 12;
  }

  .site-main {
    padding: 1.5rem 1rem 3rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-nav {
    transition: none;
  }

  .btn,
  .nav-link,
  .icp-link {
    transition: none;
  }
}