/* ============ 基础与变量 ============ */
:root {
  --ice: #1B5B7A;
  --flame: #FF4D2E;
  --light-ice: #E8F0F5;
  --deep-ice: #0D3B4F;
  --still-gray: #D0D7DD;
  --moss: #5C7A6B;
  --clay: #C57B57;
  --cream: #FAF7F0;
  --ink: #1A1D20;
  --paper: #F0F4F8;
  --font-display: 'Noto Sans SC', 'Impact', 'Arial Black', sans-serif;
  --font-body: 'Noto Serif SC', 'Georgia', serif;
  --font-caption: 'Noto Sans SC', 'Arial', sans-serif;
  --container-w: 1240px;
  --shadow-hard: 6px 6px 0 rgba(27, 91, 122, 0.16);
  --shadow-deep: 8px 8px 0 rgba(13, 59, 79, 0.22);
}

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

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

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  color: var(--ink);
  background-color: var(--light-ice);
  background-image:
    linear-gradient(rgba(27, 91, 122, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(27, 91, 122, 0.05) 1px, transparent 1px);
  background-size: 28px 28px;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 900;
  line-height: 1.16;
  letter-spacing: -0.02em;
  color: var(--deep-ice);
}

p, ul, ol, figure, blockquote, dl, dd { margin: 0; }
ul[class], ol[class] { list-style: none; padding: 0; }

a {
  color: var(--ice);
  text-underline-offset: 3px;
  text-decoration-thickness: 2px;
}
a:hover { color: var(--flame); }

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

::selection { background: var(--flame); color: #fff; }

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

.container {
  width: calc(100% - 40px);
  max-width: var(--container-w);
  margin-inline: auto;
}

/* ============ 跳过链接 ============ */
.skip-link {
  position: absolute;
  top: -64px;
  left: 16px;
  z-index: 300;
  background: var(--flame);
  color: #fff;
  font-family: var(--font-caption);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-decoration: none;
  padding: 10px 18px;
  border: 2px solid #fff;
  box-shadow: 5px 5px 0 rgba(0, 0, 0, 0.35);
  transition: top 0.2s ease;
}
.skip-link:focus-visible { top: 12px; }

/* ============ 共享头部 ============ */
.site-header {
  position: relative;
  z-index: 100;
  background:
    radial-gradient(circle at 82% -20%, rgba(255, 255, 255, 0.14), transparent 320px),
    radial-gradient(circle at 8% 120%, rgba(255, 77, 46, 0.16), transparent 260px),
    linear-gradient(135deg, var(--deep-ice) 0%, #103a4e 100%);
  border-bottom: 4px solid var(--flame);
}

.site-header::before {
  content: "";
  display: block;
  height: 5px;
  background: linear-gradient(90deg,
    var(--flame) 0%, var(--flame) 10%,
    var(--clay) 10%, var(--clay) 22%,
    var(--moss) 22%, var(--moss) 34%,
    var(--ice) 34%, var(--ice) 78%,
    var(--flame) 78%, var(--flame) 100%);
}

.site-header__top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding-block: 18px 16px;
}

.site-header__brand { flex: 0 0 auto; }

.site-header__brand-link {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  color: #fff;
  text-decoration: none;
}

.site-header__emblem {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  flex: 0 0 auto;
  background: var(--flame);
  color: #fff;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 18px;
  letter-spacing: 0.04em;
  box-shadow: 5px 5px 0 rgba(255, 255, 255, 0.12);
}

.site-header__word {
  display: flex;
  flex-direction: column;
}

.site-header__title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 24px;
  line-height: 1.1;
  letter-spacing: 0.03em;
  color: #fff;
}

.site-header__tagline {
  font-family: var(--font-caption);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: rgba(240, 244, 248, 0.55);
  margin-top: 4px;
}

.site-header__index {
  display: flex;
  align-items: center;
  gap: 16px;
}

.site-header__index-caption {
  font-family: var(--font-caption);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--flame);
  border-left: 3px solid var(--flame);
  padding-left: 10px;
  white-space: nowrap;
  line-height: 1.4;
}

.site-header__index-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-header__index-link {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  font-family: var(--font-caption);
  font-size: 13px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--paper);
  text-decoration: none;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(240, 244, 248, 0.28);
  padding: 9px 11px;
  transition: background 0.2s, border-color 0.2s, color 0.2s, transform 0.2s;
}

.site-header__index-link span {
  font-size: 11px;
  font-weight: 400;
  color: var(--flame);
}

.site-header__index-link:hover {
  color: #fff;
  border-color: var(--flame);
  background: rgba(255, 77, 46, 0.18);
  transform: translateY(-2px);
}

.site-header__nav-row {
  background: linear-gradient(180deg, var(--ice) 0%, #185170 100%);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.site-header__nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 58px;
}

.site-nav { min-width: 0; }

.site-nav__list {
  display: flex;
  flex-wrap: wrap;
  align-items: stretch;
  gap: 2px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-nav__item { list-style: none; }

.site-nav__link {
  display: block;
  font-family: var(--font-caption);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.03em;
  color: rgba(240, 244, 248, 0.85);
  text-decoration: none;
  padding: 17px 16px 14px;
  border-bottom: 3px solid transparent;
  transition: color 0.2s, background 0.2s, border-color 0.2s;
}

.site-nav__link:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.07);
  border-bottom-color: var(--flame);
}

.site-nav__link[aria-current="page"] {
  color: #fff;
  background: rgba(255, 77, 46, 0.16);
  border-bottom-color: var(--flame);
}

.site-nav__toggle {
  display: none;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 9px 15px;
  font-family: var(--font-caption);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--paper);
  background: transparent;
  border: 1px solid rgba(240, 244, 248, 0.4);
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}

.site-nav__toggle:hover {
  border-color: var(--flame);
  background: rgba(255, 77, 46, 0.14);
}

.site-nav__toggle[aria-expanded="true"] {
  background: var(--flame);
  border-color: var(--flame);
}

.site-nav__toggle-box {
  position: relative;
  display: inline-block;
  width: 18px;
  height: 14px;
  flex: 0 0 auto;
}

.site-nav__toggle-bar,
.site-nav__toggle-bar::before,
.site-nav__toggle-bar::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  background: currentColor;
  transition: transform 0.25s ease, top 0.25s ease, background 0.25s ease;
}

.site-nav__toggle-bar { top: 6px; }
.site-nav__toggle-bar::before { top: -6px; }
.site-nav__toggle-bar::after { top: 6px; }

.site-nav__toggle[aria-expanded="true"] .site-nav__toggle-bar { background: transparent; }
.site-nav__toggle[aria-expanded="true"] .site-nav__toggle-bar::before { top: 0; transform: rotate(45deg); }
.site-nav__toggle[aria-expanded="true"] .site-nav__toggle-bar::after { top: 0; transform: rotate(-45deg); }

.site-nav__toggle-text {
  font-family: var(--font-caption);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

/* ============ 共享页脚 ============ */
.site-footer {
  background: linear-gradient(180deg, var(--deep-ice) 0%, #081f2b 100%);
  color: rgba(240, 244, 248, 0.72);
  border-top: 4px solid var(--flame);
  margin-top: clamp(56px, 8vw, 110px);
}

.site-footer__grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1.4fr;
  gap: clamp(24px, 4vw, 56px);
  padding-block: 44px 36px;
}

.site-footer__panel {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  min-width: 0;
}

.site-footer__brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 26px;
  letter-spacing: 0.02em;
  text-decoration: none;
}

.site-footer__brand::before {
  content: "";
  width: 12px;
  height: 12px;
  flex: 0 0 auto;
  background: var(--flame);
  box-shadow: 3px 3px 0 rgba(255, 255, 255, 0.14);
}

.site-footer__tagline {
  font-family: var(--font-caption);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: rgba(240, 244, 248, 0.45);
  margin-top: 8px;
}

.site-footer__about {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.8;
  color: rgba(240, 244, 248, 0.8);
  margin-top: 16px;
  max-width: 34ch;
}

.site-footer__trust {
  font-family: var(--font-caption);
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: rgba(240, 244, 248, 0.75);
  border-left: 3px solid var(--moss);
  padding-left: 10px;
  margin-top: 18px;
}

.site-footer__heading {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  font-family: var(--font-caption);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--flame);
  margin: 0 0 16px;
}

.site-footer__heading::after {
  content: "";
  flex: 1;
  height: 1px;
  background: rgba(240, 244, 248, 0.16);
}

.site-footer__list {
  display: grid;
  gap: 10px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-footer__list a {
  display: inline-block;
  font-family: var(--font-caption);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: rgba(240, 244, 248, 0.78);
  text-decoration: none;
  padding: 2px 0;
  transition: color 0.2s, padding-left 0.2s;
}

.site-footer__list a:hover {
  color: var(--flame);
  padding-left: 6px;
}

.site-footer__contact {
  display: grid;
  gap: 8px;
  list-style: none;
  margin: 18px 0 0;
  padding: 14px 0 0;
  border-top: 1px solid rgba(240, 244, 248, 0.16);
  font-family: var(--font-caption);
  font-size: 13px;
  letter-spacing: 0.02em;
  color: rgba(240, 244, 248, 0.65);
  line-height: 1.6;
}

.site-footer__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 22px;
  border-top: 1px solid rgba(240, 244, 248, 0.16);
  padding-block: 18px;
  font-family: var(--font-caption);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: rgba(240, 244, 248, 0.55);
}

.site-footer__meta a { color: rgba(240, 244, 248, 0.8); }
.site-footer__meta a:hover { color: var(--flame); }
.site-footer__meta-note { flex-basis: 100%; color: rgba(240, 244, 248, 0.42); }

/* ============ 通用按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-caption);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1;
  padding: 14px 24px;
  border: 2px solid var(--deep-ice);
  background: var(--paper);
  color: var(--ink);
  text-decoration: none;
  cursor: pointer;
  box-shadow: 4px 4px 0 rgba(13, 59, 79, 0.28);
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.2s ease, color 0.2s ease;
}

.btn:hover {
  color: var(--ink);
  background: #fff;
  transform: translate(-2px, -2px);
  box-shadow: 6px 6px 0 rgba(13, 59, 79, 0.28);
}

.btn:active {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 rgba(13, 59, 79, 0.28);
}

.btn--accent {
  background: var(--flame);
  border-color: var(--flame);
  color: #fff;
  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.22);
}

.btn--accent:hover {
  background: #e63d1f;
  border-color: #e63d1f;
  color: #fff;
}

.btn--ghost {
  background: transparent;
  border-color: var(--ice);
  color: var(--ice);
  box-shadow: none;
}

.btn--ghost:hover {
  background: rgba(27, 91, 122, 0.08);
  color: var(--ice);
}

/* ============ 标签 ============ */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-caption);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--deep-ice);
  background: var(--cream);
  border: 2px solid var(--deep-ice);
  box-shadow: 3px 3px 0 rgba(13, 59, 79, 0.18);
  padding: 5px 10px;
  text-decoration: none;
}

.tag--flame {
  background: var(--flame);
  border-color: var(--flame);
  color: #fff;
  box-shadow: 3px 3px 0 rgba(0, 0, 0, 0.18);
}

.tag--moss {
  background: var(--moss);
  border-color: var(--moss);
  color: #fff;
}

/* ============ 章节标题 ============ */
.label-index {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-caption);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--flame);
}

.section-head {
  padding-block: clamp(28px, 5vw, 56px) 20px;
  border-bottom: 2px solid var(--deep-ice);
  margin-bottom: clamp(24px, 4vw, 40px);
}

.section-head__title {
  margin-top: 10px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 5vw, 52px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--deep-ice);
}

.section-head__lead {
  margin-top: 12px;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.8;
  color: #45525c;
  max-width: 64ch;
}

/* ============ 画板与卡片 ============ */
.stack-panel {
  position: relative;
  border: 2px solid var(--deep-ice);
  background: var(--paper);
  box-shadow: var(--shadow-hard);
  padding: clamp(20px, 4vw, 40px);
  margin-bottom: clamp(24px, 4vw, 40px);
}

.stack-panel::before {
  content: attr(data-index);
  position: absolute;
  top: -15px;
  left: 14px;
  background: var(--flame);
  color: #fff;
  font-family: var(--font-caption);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  padding: 4px 10px;
  box-shadow: 3px 3px 0 rgba(0, 0, 0, 0.18);
}

.panel-card {
  border: 2px solid var(--deep-ice);
  background: var(--light-ice);
  box-shadow: var(--shadow-hard);
  padding: clamp(18px, 3vw, 28px);
}

.data-card {
  border: 2px solid var(--deep-ice);
  background: var(--cream);
  box-shadow: var(--shadow-hard);
  padding: clamp(18px, 3vw, 28px);
}

.data-card--deep {
  background: var(--deep-ice);
  border-color: var(--deep-ice);
  color: var(--paper);
  box-shadow: var(--shadow-deep);
}

/* ============ 网格 ============ */
.grid {
  display: grid;
  gap: 24px;
}

.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

/* ============ 图片容器 ============ */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  background: linear-gradient(135deg, var(--still-gray), var(--light-ice));
  border: 2px solid var(--deep-ice);
  box-shadow: var(--shadow-hard);
  aspect-ratio: 16 / 9;
}

.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.media-frame:hover img { transform: scale(1.03); }

.media-frame--4x3 { aspect-ratio: 4 / 3; }
.media-frame--1x1 { aspect-ratio: 1 / 1; }
.media-frame--3x4 { aspect-ratio: 3 / 4; }
.media-frame--wide { aspect-ratio: 21 / 9; }

/* ============ 面包屑 ============ */
.breadcrumbs {
  font-family: var(--font-caption);
  font-size: 13px;
  letter-spacing: 0.04em;
  padding-block: 18px 6px;
}

.breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 8px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.breadcrumbs li {
  display: inline-flex;
  align-items: center;
}

.breadcrumbs li + li::before {
  content: "→";
  color: var(--flame);
  margin-right: 8px;
  font-weight: 700;
}

.breadcrumbs a {
  color: var(--ice);
  font-weight: 600;
  text-decoration: none;
}

.breadcrumbs a:hover { color: var(--flame); }
.breadcrumbs [aria-current] {
  color: var(--deep-ice);
  font-weight: 700;
}

/* ============ 长文正文 ============ */
.prose {
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.85;
  color: var(--ink);
  background: var(--cream);
  border: 2px solid var(--still-gray);
  box-shadow: var(--shadow-hard);
  padding: clamp(22px, 4vw, 48px);
}

.prose p + p { margin-top: 1.1em; }

.prose h2,
.prose h3 {
  font-family: var(--font-display);
  font-weight: 900;
  color: var(--deep-ice);
  margin-top: 1.8em;
}

.prose h2 { font-size: 24px; }
.prose h3 { font-size: 20px; }

.prose ul {
  list-style: square;
  padding-left: 1.3em;
  margin: 0.8em 0;
}

.prose ol {
  list-style: decimal;
  padding-left: 1.3em;
  margin: 0.8em 0;
}

.prose li + li { margin-top: 0.4em; }

.prose blockquote {
  border-left: 4px solid var(--flame);
  background: var(--light-ice);
  padding: 14px 18px;
  margin: 1.2em 0;
  color: #33414c;
}

/* ============ 滚动显现 ============ */
[data-reveal][data-reveal-ready] {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s cubic-bezier(0.22, 0.61, 0.36, 1), transform 0.7s cubic-bezier(0.22, 0.61, 0.36, 1);
  transition-delay: var(--reveal-delay, 0s);
}

[data-reveal="left"][data-reveal-ready] { transform: translateX(-32px); }
[data-reveal="right"][data-reveal-ready] { transform: translateX(32px); }
[data-reveal="up"][data-reveal-ready] { transform: translateY(32px); }
[data-reveal="scale"][data-reveal-ready] { transform: scale(0.94); }

[data-reveal][data-reveal-ready][data-reveal-visible] {
  opacity: 1;
  transform: none;
}

/* ============ 响应式 ============ */
@media (max-width: 1024px) {
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .site-footer__grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 960px) {
  .site-header__top {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
    padding-block: 16px 14px;
  }

  .site-header__index {
    width: 100%;
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .site-header__nav-inner {
    flex-wrap: wrap;
    padding-block: 10px;
  }

  .site-nav {
    display: none;
    order: 2;
    width: 100%;
  }

  .site-nav[data-open] { display: block; }

  .site-nav__list {
    flex-direction: column;
    gap: 0;
    padding: 4px 0 12px;
  }

  .site-nav__item { width: 100%; }

  .site-nav__link {
    border-bottom: 0;
    border-left: 3px solid transparent;
    padding: 14px 12px;
  }

  .site-nav__link:hover,
  .site-nav__link[aria-current="page"] { border-left-color: var(--flame); }

  .site-nav__toggle {
    display: inline-flex;
    order: 1;
    margin-left: auto;
  }
}

@media (max-width: 720px) {
  .grid--2,
  .grid--3,
  .grid--4 { grid-template-columns: 1fr; }

  .site-footer__grid {
    grid-template-columns: 1fr;
    gap: 32px;
    padding-block: 32px 24px;
  }

  .site-footer__meta { gap: 8px 16px; }
}

@media (max-width: 540px) {
  .container { width: calc(100% - 28px); }

  .site-header__brand-link { gap: 10px; }

  .site-header__emblem {
    width: 44px;
    height: 44px;
    font-size: 16px;
  }

  .site-header__title { font-size: 20px; }

  .site-header__index-link {
    padding: 7px 9px;
    font-size: 12px;
  }

  .site-header__index-caption { font-size: 11px; }
  .site-nav__toggle-text { display: none; }
}

/* ============ 动效降级 ============ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  [data-reveal],
  [data-reveal][data-reveal-ready] {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }
}