:root {
  --paper: #F4EDE4;
  --ink: #1A1A1A;
  --orange: #E4452B;
  --navy: #16324A;
  --yellow: #F5B82E;
  --yi-red: #A63A2B;
  --bai-blue: #2E4F6B;
  --line: #D6CBB9;
  --gray: #6E6E6E;
  --paper-cool: #EDF0F2;
  --header-h: 72px;
  --radius: 2px;
  --transition: 0.2s ease;
  --content-w: 1200px;
  --header-bg: rgba(244, 237, 228, 0.96);
  --sidebar-w: 86px;
  --font-serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", SimSun, serif;
  --font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-num: "DIN", "Oswald", "Bahnschrift", "Arial Narrow", sans-serif;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

html[data-scroll="true"] body {
  overflow: auto;
}

body {
  font-family: var(--font-sans);
  background-color: var(--paper);
  color: var(--ink);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

body.menu-open {
  overflow: hidden;
}

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

a {
  color: var(--ink);
  text-decoration: none;
  transition: color var(--transition), border-color var(--transition), background-color var(--transition);
}

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

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 3px;
  border-radius: 2px;
}

::selection {
  background: var(--orange);
  color: var(--paper);
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 2000;
  background: var(--navy);
  color: var(--paper);
  padding: 10px 18px;
  font-size: 14px;
  letter-spacing: 0.06em;
  border-radius: 2px;
  transform: translateY(-200%);
  transition: transform var(--transition);
}

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

.fixed-rail {
  position: fixed;
  left: 0;
  top: 0;
  width: 32px;
  height: 100vh;
  background: var(--navy);
  z-index: 50;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  padding: 14px 5px;
  writing-mode: vertical-rl;
  transform: rotate(180deg);
}

.rail-init {
  color: var(--yellow);
  font-family: var(--font-num);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.3em;
  transform: rotate(180deg);
}

.rail-year {
  color: rgba(244, 237, 228, 0.7);
  font-family: var(--font-num);
  font-size: 11px;
  letter-spacing: 0.2em;
  transform: rotate(180deg);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  background: var(--header-bg);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.skid-mark {
  background: var(--yellow);
  color: var(--ink);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.04em;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px clamp(16px, 4vw, 48px);
  border-bottom: 1px solid rgba(26, 26, 26, 0.15);
  white-space: nowrap;
  overflow-x: auto;
  scrollbar-width: none;
}

.skid-mark::-webkit-scrollbar {
  display: none;
}

.skid-mark__icon {
  font-size: 14px;
  flex-shrink: 0;
}

.skid-mark__text {
  flex-shrink: 0;
}

.skid-mark__link {
  margin-left: auto;
  flex-shrink: 0;
  background: var(--ink);
  color: var(--yellow);
  font-size: 12px;
  font-weight: 700;
  padding: 3px 12px;
  border-radius: 2px;
  transition: background var(--transition), color var(--transition), transform var(--transition);
}

.skid-mark__link:hover {
  background: var(--orange);
  color: var(--paper);
  transform: translateY(-1px);
}

.header-main {
  max-width: var(--content-w);
  margin: 0 auto;
  padding: 0 clamp(16px, 4vw, 48px);
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: clamp(16px, 3vw, 32px);
}

.brand-lockup {
  flex-shrink: 0;
}

.brand-lockup__link {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-lockup__mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  background: var(--bai-blue);
  color: var(--paper);
  font-family: var(--font-num);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.04em;
  border-radius: 2px 8px 2px 2px;
  transition: border-radius var(--transition);
}

.brand-lockup__link:hover .brand-lockup__mark {
  border-radius: 8px 2px 8px 2px;
  background: var(--orange);
}

.brand-lockup__text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand-lockup__name {
  font-family: var(--font-serif);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.05em;
}

.brand-lockup__sub {
  font-family: var(--font-num);
  font-size: 10px;
  font-weight: 600;
  color: var(--orange);
  letter-spacing: 0.28em;
  text-transform: uppercase;
}

.flag-tabs {
  display: flex;
  align-items: center;
  gap: 2px;
  margin-left: auto;
}

.flag-tab {
  position: relative;
  padding: 8px 14px;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--ink);
  clip-path: polygon(0 0, calc(100% - 8px) 0, 100% 50%, calc(100% - 8px) 100%, 0 100%, 8px 50%);
  background: transparent;
  transition: background var(--transition), color var(--transition);
}

.flag-tab::before {
  content: "";
  position: absolute;
  left: 8px;
  right: calc(8px + 8px);
  bottom: 3px;
  height: 2px;
  background: var(--orange);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.flag-tab:hover {
  background: rgba(228, 69, 43, 0.08);
  color: var(--orange);
}

.flag-tab:hover::before {
  transform: scaleX(1);
}

.flag-tab[aria-current="page"] {
  background: var(--navy);
  color: var(--paper);
  clip-path: polygon(0 0, calc(100% - 8px) 0, 100% 50%, calc(100% - 8px) 100%, 0 100%, 8px 50%);
}

.flag-tab[aria-current="page"]::before {
  transform: scaleX(1);
  background: var(--yellow);
  left: 10px;
  right: 16px;
}

.btn-download {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--orange);
  color: var(--paper);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.05em;
  padding: 10px 18px;
  border-radius: 2px;
  flex-shrink: 0;
  box-shadow: 3px 3px 0 0 rgba(26, 26, 26, 0.9);
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
}

.btn-download:hover {
  background: var(--ink);
  transform: translate(-1px, -1px);
  box-shadow: 5px 5px 0 0 rgba(228, 69, 43, 0.8);
}

.btn-download__arrow {
  font-size: 16px;
  transition: transform var(--transition);
}

.btn-download:hover .btn-download__arrow {
  transform: translateX(3px);
}

.btn-download--block {
  width: 100%;
  justify-content: center;
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  border: 1px solid var(--line);
  background: var(--paper);
  border-radius: 2px;
  flex-shrink: 0;
  transition: border-color var(--transition), background var(--transition);
}

.nav-toggle:hover {
  border-color: var(--orange);
  background: rgba(228, 69, 43, 0.06);
}

.nav-toggle__bar {
  width: 20px;
  height: 2px;
  background: var(--ink);
  transition: transform var(--transition), background var(--transition);
}

.nav-toggle:hover .nav-toggle__bar {
  background: var(--orange);
}

.mobile-nav {
  position: fixed;
  inset: 0;
  background: var(--navy);
  z-index: 300;
  padding: 24px 28px;
  display: flex;
  flex-direction: column;
  transform: translateX(102%);
  transition: transform 0.3s cubic-bezier(0.22, 1, 0.36, 1);
}

body.menu-open .mobile-nav {
  transform: translateX(0);
}

.mobile-nav__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 18px;
  border-bottom: 1px solid rgba(244, 237, 228, 0.2);
}

.mobile-nav__title {
  color: var(--paper);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.2em;
}

.mobile-nav__close {
  width: 40px;
  height: 40px;
  color: var(--paper);
  font-size: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(244, 237, 228, 0.35);
  border-radius: 2px;
  transition: background var(--transition), border-color var(--transition);
}

.mobile-nav__close:hover {
  background: var(--orange);
  border-color: var(--orange);
}

.mobile-nav__list {
  display: flex;
  flex-direction: column;
  margin-top: 28px;
  gap: 4px;
}

.mobile-nav__link {
  color: rgba(244, 237, 228, 0.88);
  font-size: 22px;
  font-weight: 500;
  padding: 12px 2px;
  border-bottom: 1px solid rgba(244, 237, 228, 0.1);
  position: relative;
  transition: color var(--transition), padding-left var(--transition);
}

.mobile-nav__link::before {
  content: "/";
  position: absolute;
  left: -2px;
  color: var(--yellow);
  font-weight: 700;
  opacity: 0;
  transition: opacity var(--transition);
}

.mobile-nav__link:hover,
.mobile-nav__link[aria-current="page"] {
  color: var(--yellow);
  padding-left: 20px;
}

.mobile-nav__link:hover::before,
.mobile-nav__link[aria-current="page"]::before {
  opacity: 1;
}

.mobile-nav__foot {
  margin-top: auto;
  padding-top: 24px;
}

.course-line {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--gray);
  margin-top: 18px;
}

.course-line span {
  display: inline-flex;
  align-items: center;
}

.course-line span + span::before {
  content: "→";
  margin-right: 6px;
  color: var(--orange);
}

.course-line--compact {
  justify-content: center;
  color: rgba(244, 237, 228, 0.6);
}

.main-content {
  min-height: 70vh;
}

/* 页脚 */
.site-footer {
  background: linear-gradient(180deg, var(--paper) 0%, var(--paper-cool) 60%, #E3E9EC 100%);
  border-top: 2px solid var(--navy);
  position: relative;
  margin-top: 80px;
}

.footer-ribbon {
  display: flex;
  gap: 6px;
  padding: 8px clamp(16px, 4vw, 48px);
  background: var(--navy);
  overflow: hidden;
}

.footer-ribbon span {
  width: 24px;
  height: 4px;
  background: rgba(244, 237, 228, 0.15);
  flex-shrink: 0;
  transform: skewX(-20deg);
}

.footer-ribbon span:nth-child(2n) {
  background: var(--yellow);
  opacity: 0.6;
}

.footer-ribbon span:nth-child(3n) {
  background: var(--orange);
  opacity: 0.7;
}

.footer-top {
  max-width: var(--content-w);
  margin: 0 auto;
  padding: 48px clamp(16px, 4vw, 48px) 32px;
}

.lane-row {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.2fr;
  gap: clamp(24px, 4vw, 56px);
}

.waypoint {
  position: relative;
}

.waypoint__title {
  font-family: var(--font-serif);
  font-size: 18px;
  font-weight: 700;
  padding-left: 12px;
  margin-bottom: 16px;
  position: relative;
  line-height: 1.4;
}

.waypoint__title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 3px;
  background: var(--yi-red);
  transform: skewX(-8deg);
}

.waypoint__title--sm {
  font-size: 15px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.waypoint__desc {
  font-size: 14px;
  color: var(--gray);
  margin-bottom: 16px;
  line-height: 1.8;
}

.waypoint__links {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.doc-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  color: var(--navy);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), color var(--transition), padding-left var(--transition);
}

.doc-link::before {
  content: "";
  width: 6px;
  height: 6px;
  border-left: 1.5px solid var(--orange);
  border-bottom: 1.5px solid var(--orange);
  transform: rotate(-45deg);
  flex-shrink: 0;
}

.doc-link:hover {
  color: var(--orange);
  padding-left: 6px;
  border-bottom-color: rgba(228, 69, 43, 0.4);
}

.waypoint__contact {
  display: flex;
  flex-direction: column;
  gap: 10px;
  font-size: 13px;
}

.waypoint__row {
  display: flex;
  gap: 8px;
  line-height: 1.5;
  color: var(--ink);
}

.waypoint__label {
  color: var(--gray);
  flex-shrink: 0;
  min-width: 38px;
  font-size: 12px;
  padding-top: 1px;
}

.copy-text {
  background: none;
  border: none;
  font-size: 13px;
  color: var(--bai-blue);
  text-decoration: underline;
  text-decoration-style: dotted;
  text-underline-offset: 3px;
  padding: 0;
  cursor: pointer;
  text-align: left;
  transition: color var(--transition);
}

.copy-text:hover {
  color: var(--orange);
}

.copy-text.is-copied {
  color: var(--orange);
  font-weight: 600;
}

.copy-text.is-copied::after {
  content: " ✓";
  color: var(--orange);
}

.footer-track {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: rgba(46, 79, 107, 0.04);
  padding: 10px 0;
  overflow: hidden;
}

.footer-track__inner {
  max-width: var(--content-w);
  margin: 0 auto;
  padding: 0 clamp(16px, 4vw, 48px);
  display: flex;
  align-items: center;
  gap: 14px;
}

.footer-track__text {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--navy);
  text-transform: uppercase;
  white-space: nowrap;
}

.footer-track__line {
  flex: 1;
  height: 2px;
  background: repeating-linear-gradient(90deg, var(--bai-blue) 0 8px, transparent 8px 12px, var(--orange) 12px 16px, transparent 16px 20px);
  opacity: 0.5;
}

.footer-bottom {
  max-width: var(--content-w);
  margin: 0 auto;
  padding: 20px clamp(16px, 4vw, 48px) 28px;
}

.footer-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 13px;
  color: var(--gray);
}

.footer-meta--bottom {
  margin-top: 8px;
  font-size: 12px;
  opacity: 0.8;
}

.footer-meta__item {
  white-space: nowrap;
}

.footer-meta__divider {
  color: var(--line);
}

.footer-meta__link {
  color: var(--gray);
  border-bottom: 1px solid transparent;
  transition: color var(--transition), border-color var(--transition);
}

.footer-meta__link:hover {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

/* 通用组件 */
.status-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  font-weight: 700;
  padding: 5px 14px;
  border-radius: 999px;
  background: rgba(22, 50, 74, 0.08);
  color: var(--navy);
  border: 1px solid transparent;
}

.status-chip--solid {
  background: var(--yellow);
  color: var(--ink);
  border-color: rgba(26, 26, 26, 0.2);
}

.pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--orange);
  flex-shrink: 0;
}

.freq-bar {
  display: flex;
  align-items: flex-end;
  gap: 3px;
  height: 36px;
}

.freq-bar i {
  display: block;
  width: 8px;
  background: var(--navy);
  min-height: 4px;
  transition: background var(--transition);
}

.freq-bar i:nth-child(2n) {
  background: var(--orange);
}

.freq-bar i:nth-child(3n) {
  background: var(--yellow);
}

.freq-bar:hover i {
  background: var(--bai-blue);
}

.portal-card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 2px 10px 2px 10px;
  padding: 24px 20px;
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 18px 100%, 0 calc(100% - 18px));
  transition: background var(--transition), box-shadow var(--transition), transform var(--transition);
}

.portal-card:hover {
  background: var(--paper);
  box-shadow: 6px 6px 0 -2px rgba(228, 69, 43, 0.35);
  transform: translate(-2px, -2px);
}

.portal-card__icon {
  display: inline-flex;
  width: 40px;
  height: 40px;
  background: var(--navy);
  color: var(--paper);
  font-family: var(--font-num);
  font-size: 18px;
  font-weight: 800;
  align-items: center;
  justify-content: center;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%);
  margin-bottom: 16px;
}

.portal-card__title {
  font-family: var(--font-serif);
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 8px;
}

.portal-card__text {
  font-size: 14px;
  color: var(--gray);
  line-height: 1.6;
}

.metric-strip {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.metric-item {
  flex: 1;
  min-width: 90px;
  background: var(--navy);
  color: var(--paper);
  padding: 12px 14px;
  border-radius: 2px;
  border-bottom: 3px solid var(--orange);
  transition: background var(--transition);
}

.metric-item:hover {
  background: var(--ink);
}

.metric-item__num {
  font-family: var(--font-num);
  font-size: 24px;
  font-weight: 700;
  line-height: 1;
}

.metric-item__label {
  font-size: 12px;
  color: rgba(244, 237, 228, 0.7);
  margin-top: 4px;
}

.accordion {
  border-bottom: 1px solid var(--line);
}

.accordion__trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 4px;
  background: transparent;
  border: none;
  font-family: var(--font-serif);
  font-size: 17px;
  font-weight: 700;
  text-align: left;
  cursor: pointer;
  transition: color var(--transition), background var(--transition);
}

.accordion__trigger:hover {
  color: var(--orange);
}

.accordion__arrow {
  font-size: 18px;
  transition: transform var(--transition), color var(--transition);
  flex-shrink: 0;
  display: inline-block;
}

.accordion__trigger[aria-expanded="true"] .accordion__arrow {
  transform: rotate(45deg);
}

.accordion__panel {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}

.accordion__inner {
  padding: 0 4px 20px;
  font-size: 15px;
  color: var(--gray);
  line-height: 1.8;
}

.scroll-top {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 150;
  width: 44px;
  height: 44px;
  background: var(--navy);
  color: var(--paper);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 2px;
  box-shadow: 0 2px 12px rgba(26, 26, 26, 0.2);
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition: opacity var(--transition), transform var(--transition), background var(--transition), visibility 0.2s;
}

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

.scroll-top:hover {
  background: var(--orange);
}

.scroll-top__arrow {
  font-size: 18px;
}

/* 固定左侧轨道 */
.main-content-wrap {
  max-width: var(--content-w);
  margin: 0 auto;
  padding: 0 clamp(16px, 4vw, 48px);
}

.page-rule {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 16px 0 12px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--line);
}

.page-rule__title {
  font-family: var(--font-serif);
  font-size: 15px;
  font-weight: 700;
  color: var(--navy);
  letter-spacing: 0.1em;
  white-space: nowrap;
}

.page-rule__line {
  flex: 1;
  height: 1px;
  background: repeating-linear-gradient(90deg, var(--bai-blue) 0 6px, transparent 6px 10px);
  opacity: 0.4;
}

/* 文本大纲 */
.section-kicker {
  font-family: var(--font-num);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--orange);
  margin-bottom: 8px;
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(24px, 4vw, 44px);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 16px;
  color: var(--gray);
  max-width: 560px;
  line-height: 1.8;
}

/* 响应式 */
@media (max-width: 1024px) {
  .flag-tabs {
    display: none;
  }

  .nav-toggle {
    display: flex;
    margin-left: auto;
  }

  .header-main {
    height: auto;
    min-height: 64px;
    padding-top: 8px;
    padding-bottom: 8px;
  }

  .btn-download {
    display: none;
  }

  .mobile-nav .btn-download {
    display: flex;
  }

  .lane-row {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 640px) {
  :root {
    --header-h: 60px;
  }

  .fixed-rail {
    display: none;
  }

  .skid-mark {
    font-size: 12px;
  }

  .skid-mark__link {
    font-size: 11px;
    padding: 2px 8px;
  }

  .brand-lockup__name {
    font-size: 14px;
  }

  .brand-lockup__mark {
    width: 32px;
    height: 32px;
    font-size: 13px;
  }

  .nav-toggle {
    width: 40px;
    height: 40px;
  }

  .mobile-nav {
    padding: 18px 20px;
  }

  .mobile-nav__link {
    font-size: 18px;
    padding: 10px 2px;
  }

  .lane-row {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .footer-top {
    padding-top: 32px;
  }

  .footer-meta {
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
  }

  .footer-meta__divider {
    display: none;
  }

  .footer-track__inner {
    flex-wrap: wrap;
  }

  .footer-track__line {
    min-width: 60px;
  }
}

@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;
  }

  .skip-link,
  .mobile-nav,
  .scroll-top {
    transition: none;
  }
}