@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+KR:wght@300;400;500;700&display=swap');

/* =====================
   CSS 变量 & 全局重置
   ===================== */
:root {
  --c-bg:        #000000;
  --c-bg2:       #121212;
  --c-bg3:       #1a1a1a;
  --c-border:    #2a2a2a;
  --c-border-hi: #3d3d3d;
  --c-text:      #e0e0e0;
  --c-text-dim:  #888888;
  --c-white:     #ffffff;
  --c-blue:      #1a3a6b;
  --c-blue-hi:   #2255aa;
  --c-blue-glow: #3a7ff655;
  --c-gold:      #c8a850;
  --c-gold-dim:  #7a6030;
  --c-accent:    #2255aa;
  --c-accent2:   #4a90d9;
  --radius-card: 28px;
  --radius-sm:   8px;
  --nav-h:       60px;
  --anchor-h:    44px;
  --sticky-top:  calc(var(--nav-h) + var(--anchor-h));
  --font-main:   'Noto Sans KR', 'Noto Sans', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --transition:  0.22s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  color-scheme: dark;
  font-size: 17px;
  -webkit-text-size-adjust: 100%;
}

body.oled-dark {
  background: var(--c-bg);
  color: var(--c-text);
  font-family: var(--font-main);
  font-weight: 400;
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: hidden;
}

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

a {
  color: var(--c-accent2);
  text-decoration: none;
  transition: color var(--transition);
}
a:hover, a:focus-visible {
  color: var(--c-white);
}
a:focus-visible {
  outline: 2px solid var(--c-accent2);
  outline-offset: 3px;
  border-radius: 3px;
}

ul, menu {
  list-style: none;
}

/* scroll margin for sticky nav */
section[id] {
  scroll-margin-top: var(--sticky-top);
}

/* =====================
   站点包装
   ===================== */
.site-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* =====================
   顶部 Header
   ===================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-h);
  background: rgba(0, 0, 0, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--c-border);
  z-index: 1000;
}

.header-inner {
  max-width: 1280px;
  margin: 0 auto;
  height: 100%;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 16px;
}

.brand-mark {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  color: var(--c-white);
  text-decoration: none;
}
.brand-mark:hover {
  color: var(--c-white);
}
.brand-icon {
  width: 36px;
  height: 36px;
  border-radius: 6px;
}
.brand-text-icon {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--c-gold);
  border: 1px solid var(--c-gold-dim);
  padding: 4px 8px;
  border-radius: 6px;
}

/* 桌面菜单 */
.desktop-nav {
  flex: 1;
}
.desktop-menu {
  display: flex;
  gap: 4px;
  align-items: center;
  flex-wrap: wrap;
}
.desktop-menu li a {
  display: block;
  padding: 8px 12px;
  font-size: 14px;
  font-weight: 500;
  color: var(--c-text-dim);
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
  min-height: 40px;
  line-height: 24px;
}
.desktop-menu li a:hover,
.desktop-menu li a:focus-visible {
  color: var(--c-white);
  background: var(--c-bg3);
}

/* CTA 按钮 */
.cta-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 8px 20px;
  font-size: 14px;
  font-weight: 700;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  letter-spacing: 0.03em;
  white-space: nowrap;
}
.header-cta {
  background: var(--c-blue-hi);
  color: var(--c-white);
  border: 1px solid var(--c-blue-hi);
  flex-shrink: 0;
}
.header-cta:hover {
  background: var(--c-accent2);
  border-color: var(--c-accent2);
  color: var(--c-white);
  box-shadow: 0 0 10px var(--c-blue-glow);
}
.cta-primary {
  background: var(--c-blue-hi);
  color: var(--c-white);
  border: 1px solid var(--c-blue-hi);
  font-size: 16px;
  padding: 12px 32px;
  min-height: 48px;
}
.cta-primary:hover {
  background: var(--c-accent2);
  border-color: var(--c-accent2);
  color: var(--c-white);
  box-shadow: 0 0 16px var(--c-blue-glow);
}
.cta-ghost {
  background: transparent;
  color: var(--c-text);
  border: 1px solid var(--c-border-hi);
  font-size: 16px;
  padding: 12px 28px;
  min-height: 48px;
}
.cta-ghost:hover {
  border-color: var(--c-accent2);
  color: var(--c-white);
}

/* details 导航（移动端） */
.nav-details {
  display: none;
  position: relative;
}
.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  cursor: pointer;
  list-style: none;
  padding: 8px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--c-border);
  background: transparent;
}
.nav-toggle::-webkit-details-marker { display: none; }
.hamburger-bar {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--c-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}
details[open] .hamburger-bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
details[open] .hamburger-bar:nth-child(2) { opacity: 0; }
details[open] .hamburger-bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  min-width: 200px;
  background: var(--c-bg2);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-card);
  padding: 8px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  z-index: 999;
  box-shadow: 0 8px 32px rgba(0,0,0,0.8);
}
.nav-menu li a {
  display: block;
  padding: 10px 16px;
  font-size: 15px;
  color: var(--c-text);
  border-radius: 16px;
  min-height: 44px;
  line-height: 24px;
  transition: background var(--transition), color var(--transition);
}
.nav-menu li a:hover {
  background: var(--c-bg3);
  color: var(--c-white);
}

/* =====================
   粘性锚点条
   ===================== */
.sticky-anchor-bar {
  position: sticky;
  top: var(--nav-h);
  z-index: 900;
  background: rgba(18, 18, 18, 0.96);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--c-border);
  height: var(--anchor-h);
  overflow: hidden;
}
.anchor-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
  height: 100%;
  display: flex;
  align-items: center;
  gap: 0;
  overflow-x: auto;
  scrollbar-width: none;
}
.anchor-inner::-webkit-scrollbar { display: none; }
.anchor-link {
  display: inline-flex;
  align-items: center;
  padding: 0 14px;
  height: 44px;
  font-size: 13px;
  font-weight: 500;
  color: var(--c-text-dim);
  white-space: nowrap;
  border-right: 1px solid var(--c-border);
  transition: color var(--transition), background var(--transition);
}
.anchor-link:first-child { border-left: 1px solid var(--c-border); }
.anchor-link:hover {
  color: var(--c-white);
  background: var(--c-bg3);
}

/* =====================
   Hero 区块
   ===================== */
.hero-wrap {
  position: relative;
  min-height: 45vh;
  background: var(--c-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  margin-top: calc(var(--nav-h) + var(--anchor-h));
  padding: 60px 20px 100px;
}

.hero-bg-num {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: clamp(120px, 22vw, 280px);
  font-weight: 700;
  color: transparent;
  -webkit-text-stroke: 1px var(--c-border-hi);
  letter-spacing: -0.02em;
  user-select: none;
  pointer-events: none;
  z-index: 0;
  white-space: nowrap;
  opacity: 0.35;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 720px;
}

.hero-logo {
  margin: 0 auto 20px;
}
.hero-logo-img {
  max-height: 60px;
  width: auto;
  margin: 0 auto;
}

.hero-h1 {
  font-size: clamp(26px, 5vw, 52px);
  font-weight: 700;
  color: var(--c-white);
  line-height: 1.2;
  margin-bottom: 16px;
  letter-spacing: -0.01em;
  text-shadow: 0 0 10px rgba(34, 85, 170, 0.4);
}

.hero-sub {
  font-size: clamp(15px, 2vw, 18px);
  color: var(--c-text-dim);
  margin-bottom: 32px;
  line-height: 1.6;
}

.hero-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}

/* 斜切底边 */
.hero-skew {
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 60px;
  background: var(--c-bg2);
  clip-path: polygon(0 100%, 100% 0, 100% 100%);
  z-index: 2;
}

/* =====================
   主体内容
   ===================== */
.site-main {
  background: var(--c-bg2);
  flex: 1;
}

.content-section {
  max-width: 1280px;
  margin: 0 auto;
  padding: 48px 20px 80px;
  display: grid;
  grid-template-columns: 220px 1fr;
  grid-template-rows: auto 1fr;
  gap: 0 40px;
  align-items: start;
}

/* aside 在左侧 */
.content-aside {
  grid-column: 1;
  grid-row: 1 / 3;
  position: sticky;
  top: var(--sticky-top);
  padding-top: 8px;
}
.aside-inner {
  border: 1px solid var(--c-border);
  border-radius: var(--radius-card);
  padding: 24px 20px;
  background: var(--c-bg3);
}
.aside-brand {
  font-size: 15px;
  font-weight: 700;
  color: var(--c-gold);
  margin-bottom: 8px;
  letter-spacing: 0.05em;
}
.aside-desc {
  font-size: 13px;
  color: var(--c-text-dim);
  line-height: 1.6;
  margin-bottom: 20px;
}
.aside-quick {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.aside-quick li a {
  display: block;
  font-size: 13px;
  color: var(--c-text-dim);
  padding: 6px 10px;
  border-radius: 8px;
  min-height: 36px;
  line-height: 24px;
  transition: color var(--transition), background var(--transition);
}
.aside-quick li a:hover {
  color: var(--c-white);
  background: var(--c-bg);
}

/* figure 装饰 */
.content-figure {
  grid-column: 2;
  grid-row: 1;
  height: 3px;
  margin-bottom: 32px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.figure-deco {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
}
.deco-line {
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, var(--c-blue-hi), transparent);
}
.deco-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--c-blue-hi);
  box-shadow: 0 0 10px var(--c-blue-glow);
}
.deco-line:last-child {
  background: linear-gradient(90deg, transparent, var(--c-border));
}

/* 正文主体 */
.page-content-body {
  grid-column: 2;
  grid-row: 2;
  min-width: 0;
}

/* =====================
   page.content 内 section 样式
   ===================== */
.page-content-body section {
  border: 1px solid var(--c-border);
  border-radius: var(--radius-card);
  padding: 40px 36px;
  margin-bottom: 32px;
  background: var(--c-bg);
  position: relative;
  overflow: hidden;
  transition: border-color var(--transition);
}
.page-content-body section:hover {
  border-color: var(--c-border-hi);
}
.page-content-body section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--c-blue-hi), var(--c-accent2), transparent);
  opacity: 0;
  transition: opacity var(--transition);
}
.page-content-body section:hover::before {
  opacity: 1;
}

.page-content-body h2,
.page-content-body h3 {
  color: var(--c-white);
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 16px;
}
.page-content-body h2 {
  font-size: clamp(20px, 3vw, 26px);
  letter-spacing: -0.01em;
}
.page-content-body h3 {
  font-size: clamp(17px, 2.2vw, 20px);
}

/* h2 > span 装饰（build 自动包 span） */
.page-content-body h2 > span,
.page-content-body h3 > span {
  position: relative;
  display: inline;
}
.page-content-body h2 > span::after {
  content: '';
  position: absolute;
  bottom: -3px;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--c-blue-hi);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}
.page-content-body section:hover h2 > span::after {
  transform: scaleX(1);
}

.page-content-body p {
  color: var(--c-text);
  font-size: 16px;
  line-height: 1.8;
  margin-bottom: 14px;
}
.page-content-body p:last-child {
  margin-bottom: 0;
}

.page-content-body ul,
.page-content-body ol {
  padding-left: 20px;
  margin-bottom: 14px;
  color: var(--c-text);
}
.page-content-body li {
  margin-bottom: 6px;
  line-height: 1.7;
  font-size: 16px;
}

.page-content-body strong {
  color: var(--c-white);
  font-weight: 700;
}

.page-content-body a {
  color: var(--c-accent2);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.page-content-body a:hover {
  color: var(--c-white);
}

.page-content-body table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 16px;
  font-size: 15px;
}
.page-content-body th,
.page-content-body td {
  border: 1px solid var(--c-border);
  padding: 10px 14px;
  text-align: left;
}
.page-content-body th {
  background: var(--c-bg2);
  color: var(--c-white);
  font-weight: 700;
}
.page-content-body td {
  color: var(--c-text);
}
.page-content-body tr:hover td {
  background: var(--c-bg3);
}

/* 问答 */
.page-content-body details {
  border: 1px solid var(--c-border);
  border-radius: var(--radius-sm);
  margin-bottom: 10px;
  overflow: hidden;
}
.page-content-body details summary {
  padding: 12px 16px;
  cursor: pointer;
  font-weight: 600;
  color: var(--c-text);
  min-height: 44px;
  display: flex;
  align-items: center;
  background: var(--c-bg2);
  transition: background var(--transition);
}
.page-content-body details summary:hover {
  background: var(--c-bg3);
}
.page-content-body details > *:not(summary) {
  padding: 14px 16px;
}

/* =====================
   页脚
   ===================== */
.site-footer {
  background: var(--c-bg);
  border-top: 1px solid var(--c-border);
  padding: 32px 20px;
  text-align: center;
}
.footer-brand {
  font-size: 15px;
  font-weight: 600;
  color: var(--c-text-dim);
  margin-bottom: 10px;
}
.site-footer small {
  display: block;
}
.footer-copy {
  font-size: 13px;
  color: var(--c-border-hi);
  line-height: 1.6;
}

/* =====================
   动效 & prefers-reduced-motion
   ===================== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  html {
    scroll-behavior: auto;
  }
}

/* =====================
   响应式断点
   ===================== */

/* 平板 ~1024px */
@media (max-width: 1024px) {
  .content-section {
    grid-template-columns: 180px 1fr;
    gap: 0 28px;
  }
  .desktop-menu li a {
    padding: 8px 10px;
    font-size: 13px;
  }
}

/* 移动端 ~768px */
@media (max-width: 768px) {
  .desktop-nav {
    display: none;
  }
  .nav-details {
    display: block;
  }
  .header-inner {
    gap: 10px;
  }

  .content-section {
    grid-template-columns: 1fr;
    padding: 28px 16px 60px;
  }
  .content-aside {
    grid-column: 1;
    grid-row: 3;
    position: static;
    margin-top: 32px;
  }
  .content-figure {
    grid-column: 1;
    grid-row: 1;
    margin-bottom: 20px;
  }
  .page-content-body {
    grid-column: 1;
    grid-row: 2;
  }

  .page-content-body section {
    padding: 28px 20px;
    border-radius: 20px;
    margin-bottom: 20px;
  }

  .hero-wrap {
    min-height: 42vh;
    padding: 48px 16px 80px;
  }
  .hero-h1 {
    font-size: clamp(22px, 7vw, 36px);
  }

  .sticky-anchor-bar {
    display: none;
  }
  section[id] {
    scroll-margin-top: var(--nav-h);
  }

  .hero-bg-num {
    font-size: clamp(90px, 28vw, 180px);
  }
}

/* 小屏 ~375px */
@media (max-width: 480px) {
  .header-cta {
    display: none;
  }
  .hero-actions {
    flex-direction: column;
    align-items: center;
  }
  .cta-primary,
  .cta-ghost {
    width: 100%;
    max-width: 300px;
    justify-content: center;
  }
  .page-content-body section {
    padding: 22px 16px;
  }
  .hero-wrap {
    padding-top: 40px;
    padding-bottom: 72px;
  }
}