/* ============================================================
   博鱼智汇 · BOYU INSIGHT
   共享样式 /assets/site.css
   设计基因：专题研究板 · 非对称编辑部 · 深空蓝 × 亮橙
   ============================================================ */

/* ---------- 1. 变量与重置 ---------- */
:root {
  --color-deep: #0A1B3D;
  --color-deep-lt: #1B3A7B;
  --color-accent: #F2633A;
  --color-paper: #F4F6FA;
  --color-ink: #0A0F1C;
  --color-body: #16233B;
  --color-muted: #54617A;
  --color-line: #D9E1EC;

  --font-sans: "Noto Sans SC", "Noto Sans CJK SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "JetBrains Mono", "SF Mono", "Cascadia Code", Consolas, "Liberation Mono", monospace;

  --header-h: 72px;
  --header-h-mobile: 60px;
  --container-w: 1280px;
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 40px;
  --space-5: 64px;
  --space-6: 96px;
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
}

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

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

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-body);
  background: var(--color-paper);
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
}

main {
  display: block;
}

#main-content:focus {
  outline: none;
}

a {
  color: inherit;
}

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

ul,
ol {
  list-style: none;
}

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

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: 2px;
}

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

h1,
h2,
h3,
h4 {
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--color-deep);
}

h1 {
  font-size: clamp(2rem, 4.5vw, 3rem);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.5rem, 2.5vw, 2rem);
}

h3 {
  font-size: 1.3rem;
}

p {
  margin-bottom: 1em;
}

p a,
li a,
.research-board__body a {
  color: var(--color-deep);
  text-decoration: underline;
  text-decoration-color: rgba(10, 27, 61, 0.3);
  text-underline-offset: 3px;
  transition: color 0.2s ease, text-decoration-color 0.2s ease;
}

p a:hover,
li a:hover,
.research-board__body a:hover {
  color: var(--color-accent);
  text-decoration-color: var(--color-accent);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.lede {
  font-size: 1.125rem;
  line-height: 1.8;
  color: var(--color-muted);
  max-width: 42em;
}

/* ---------- 2. 容器 ---------- */
.container {
  width: 100%;
  max-width: var(--container-w);
  margin-inline: auto;
  padding-inline: var(--space-3);
}

/* ---------- 3. 跳过链接 ---------- */
.skip-link {
  position: fixed;
  top: calc(var(--space-2) * -1);
  left: var(--space-3);
  z-index: 999;
  background: var(--color-accent);
  color: #fff;
  padding: 10px 20px;
  border-radius: 4px;
  font-weight: 600;
  font-size: 0.875rem;
  text-decoration: none;
  transition: top 0.3s var(--ease-out);
}

.skip-link:focus {
  top: var(--space-2);
}

/* ---------- 4. 头部 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-h);
  background: linear-gradient(to bottom, rgba(10, 15, 28, 0.78), rgba(10, 15, 28, 0.28) 60%, transparent);
  border-bottom: 1px solid transparent;
  transition: background 0.4s var(--ease-out), border-color 0.4s var(--ease-out), box-shadow 0.4s var(--ease-out);
}

.site-header.is-scrolled {
  background: rgba(244, 246, 250, 0.92);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-bottom-color: var(--color-line);
  box-shadow: 0 4px 24px rgba(10, 15, 28, 0.06);
}

.site-header__inner {
  position: relative;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.site-header__progress {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  z-index: 3;
  pointer-events: none;
}

/* ---------- 5. 品牌 Logo ---------- */
.site-brand {
  display: inline-flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  flex-shrink: 0;
  text-decoration: none;
  line-height: 1.1;
}

.site-brand__main {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: #fff;
  transition: color 0.3s var(--ease-out);
}

.site-brand__sub {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  font-weight: 400;
  letter-spacing: 0.22em;
  color: var(--color-accent);
  line-height: 1;
  text-transform: uppercase;
}

.site-header.is-scrolled .site-brand__main {
  color: var(--color-deep);
}

/* ---------- 6. 导航 ---------- */
.site-nav {
  position: static;
  background: transparent;
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.site-nav__link {
  display: block;
  position: relative;
  padding: 10px 12px;
  font-size: 0.875rem;
  font-weight: 500;
  line-height: 1.4;
  letter-spacing: 0.02em;
  color: rgba(255, 255, 255, 0.86);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.3s var(--ease-out);
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 4px;
  height: 2px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s var(--ease-out);
}

.site-nav__link:hover {
  color: #fff;
}

.site-nav__link:hover::after,
.site-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
}

.site-nav__link[aria-current="page"] {
  color: #fff;
}

.site-header.is-scrolled .site-nav__link {
  color: var(--color-body);
}

.site-header.is-scrolled .site-nav__link:hover,
.site-header.is-scrolled .site-nav__link[aria-current="page"] {
  color: var(--color-ink);
}

/* ---------- 7. 汉堡按钮 ---------- */
.site-nav__toggle {
  display: none;
  width: 44px;
  height: 44px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 6px;
  background: transparent;
  transition: border-color 0.3s var(--ease-out), background-color 0.3s var(--ease-out);
}

.site-nav__toggle:hover {
  border-color: var(--color-accent);
}

.site-header.is-scrolled .site-nav__toggle {
  border-color: var(--color-line);
}

.site-nav__toggle-bar {
  display: block;
  width: 18px;
  height: 2px;
  border-radius: 1px;
  background: #fff;
  transition: transform 0.3s var(--ease-out), opacity 0.3s var(--ease-out), background-color 0.3s var(--ease-out);
}

.site-header.is-scrolled .site-nav__toggle-bar {
  background: var(--color-deep);
}

.site-nav__toggle[aria-expanded="true"] .site-nav__toggle-bar:nth-child(2) {
  transform: translateY(7px) rotate(45deg);
}

.site-nav__toggle[aria-expanded="true"] .site-nav__toggle-bar:nth-child(3) {
  opacity: 0;
}

.site-nav__toggle[aria-expanded="true"] .site-nav__toggle-bar:nth-child(4) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---------- 8. 页脚 ---------- */
.site-footer {
  position: relative;
  background: var(--color-ink);
  color: rgba(255, 255, 255, 0.72);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 144px;
  height: 3px;
  background: var(--color-accent);
  z-index: 1;
}

.site-footer__top {
  display: grid;
  grid-template-columns: 2.8fr 1.2fr 1.2fr 1.2fr 1.8fr;
  gap: var(--space-4);
  padding: var(--space-5) 0 var(--space-4);
}

.site-footer__logo {
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: 0.04em;
  color: #fff;
  margin-bottom: 0;
}

.site-footer__logo-sub {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.625rem;
  font-weight: 400;
  letter-spacing: 0.2em;
  color: var(--color-accent);
  margin-top: 6px;
  text-transform: uppercase;
}

.site-footer__trust {
  font-size: 0.875rem;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.56);
  margin-top: var(--space-3);
  max-width: 32em;
  border-left: 2px solid var(--color-accent);
  padding-left: 12px;
}

.site-footer__title {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-2);
}

.site-footer__links li {
  margin-bottom: 10px;
}

.site-footer__links a {
  color: rgba(255, 255, 255, 0.7);
  text-decoration: none;
  font-size: 0.875rem;
  transition: color 0.2s ease;
}

.site-footer__links a:hover {
  color: var(--color-accent);
}

.site-footer__contact-list li {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin-bottom: 12px;
}

.site-footer__contact-label {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.4);
}

.site-footer__contact-value {
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.78);
  line-height: 1.5;
}

.site-footer__contact-note {
  font-size: 0.75rem;
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.4);
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding-top: var(--space-2);
  margin-top: var(--space-2);
}

.site-footer__bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.site-footer__bottom-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding-top: var(--space-3);
  padding-bottom: var(--space-3);
}

.site-footer__bottom p {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: rgba(255, 255, 255, 0.4);
  margin: 0;
}

/* ---------- 9. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 6px;
  font-size: 0.875rem;
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  border: 1px solid transparent;
  transition: background-color 0.3s var(--ease-out), color 0.3s var(--ease-out), transform 0.2s var(--ease-out), box-shadow 0.3s var(--ease-out), border-color 0.3s var(--ease-out);
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:active {
  transform: scale(0.98);
}

.btn--primary {
  background: var(--color-accent);
  color: #fff;
}

.btn--primary:hover {
  background: #e04e26;
  box-shadow: 0 8px 24px rgba(242, 99, 58, 0.28);
}

.btn--outline {
  border-color: rgba(255, 255, 255, 0.6);
  color: #fff;
}

.btn--outline:hover {
  border-color: #fff;
  background: rgba(255, 255, 255, 0.08);
}

.btn--outline-dark {
  border-color: var(--color-deep);
  color: var(--color-deep);
}

.btn--outline-dark:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: rgba(242, 99, 58, 0.06);
}

/* ---------- 10. 面包屑 ---------- */
.breadcrumb {
  font-size: 0.8125rem;
  color: var(--color-muted);
  margin-bottom: var(--space-4);
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
}

.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  color: var(--color-line);
  font-family: var(--font-mono);
}

.breadcrumb__link {
  color: var(--color-muted);
  text-decoration: none;
  transition: color 0.2s ease;
}

.breadcrumb__link:hover {
  color: var(--color-accent);
}

.breadcrumb__item[aria-current="page"] {
  color: var(--color-accent);
  font-weight: 500;
}

/* ---------- 11. 媒体容器 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  border-radius: 8px;
  background: var(--color-deep);
  display: flex;
  align-items: center;
  justify-content: center;
}

.media-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.06) 1px, transparent 1px);
  background-size: 20px 20px;
  z-index: 1;
  pointer-events: none;
}

.media-frame::after {
  content: "IMAGE";
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  color: rgba(255, 255, 255, 0.4);
  z-index: 2;
  pointer-events: none;
}

.media-frame--16x9 {
  aspect-ratio: 16 / 9;
}

.media-frame--4x3 {
  aspect-ratio: 4 / 3;
}

.media-frame--1x1 {
  aspect-ratio: 1 / 1;
}

.media-frame--3x4 {
  aspect-ratio: 3 / 4;
}

.media-frame img,
.media-frame svg {
  position: relative;
  z-index: 3;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* ---------- 12. 章节标签 ---------- */
.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--color-accent);
  text-transform: uppercase;
  line-height: 1.2;
}

.section-tag::before {
  content: "";
  width: 28px;
  height: 1px;
  background: currentColor;
  flex-shrink: 0;
}

/* ---------- 13. 研究板 ---------- */
.research-board {
  background: var(--color-paper);
  border: 1px solid var(--color-line);
  border-left: 4px solid var(--color-accent);
  border-radius: 0 10px 10px 0;
  padding: var(--space-4);
  box-shadow: 0 1px 0 rgba(10, 27, 61, 0.03);
}

.research-board__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-3);
  margin-bottom: var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--color-line);
}

.research-board__title {
  font-size: 1.1rem;
  line-height: 1.4;
  letter-spacing: 0.02em;
  color: var(--color-deep);
}

.research-board__body {
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--color-body);
}

/* ---------- 14. 首屏 ---------- */
.page-hero {
  position: relative;
  min-height: 68vh;
  display: flex;
  align-items: flex-end;
  padding: calc(var(--header-h) + var(--space-5)) 0 var(--space-6);
  background:
    radial-gradient(ellipse 65% 55% at 82% 12%, rgba(27, 58, 123, 0.72), transparent 70%),
    linear-gradient(120deg, var(--color-deep) 0%, var(--color-ink) 100%);
  color: #fff;
  overflow: hidden;
}

.page-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: 32px 32px;
  pointer-events: none;
}

.page-hero > * {
  position: relative;
  z-index: 1;
}

.page-hero h1,
.page-hero h2 {
  color: #fff;
}

.page-hero a {
  color: #fff;
}

/* ---------- 15. 滚动显现 ---------- */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out);
  transition-delay: var(--reveal-delay, 0ms);
  will-change: opacity, transform;
}

.js [data-reveal="left"] {
  transform: translateX(-24px);
}

.js [data-reveal="right"] {
  transform: translateX(24px);
}

.js [data-reveal="fade"] {
  transform: none;
}

.js [data-reveal].is-revealed {
  opacity: 1;
  transform: translate(0, 0);
}

/* ---------- 16. 响应式 ---------- */
@media (max-width: 960px) {
  :root {
    --header-h: var(--header-h-mobile);
    --space-6: 72px;
  }

  .page-hero {
    min-height: 56vh;
    padding-top: calc(var(--header-h) + var(--space-4));
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(10, 15, 28, 0.97);
    -webkit-backdrop-filter: blur(16px);
    backdrop-filter: blur(16px);
    max-height: 0;
    overflow: hidden;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    transition: max-height 0.4s var(--ease-out), border-width 0.2s ease;
  }

  .site-nav[data-open] {
    max-height: 440px;
    border-bottom-width: 1px;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: var(--space-2) var(--space-3) var(--space-3);
  }

  .site-nav__link {
    width: 100%;
    padding: 14px 4px;
    font-size: 1rem;
    color: #fff;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  }

  .site-nav__link::after {
    display: none;
  }

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

  .site-header.is-scrolled .site-nav__link {
    color: #fff;
  }

  .site-header.is-scrolled .site-nav__link:hover,
  .site-header.is-scrolled .site-nav__link[aria-current="page"] {
    color: var(--color-accent);
  }

  .site-nav__toggle {
    display: flex;
  }

  .site-footer__top {
    grid-template-columns: repeat(6, 1fr);
    gap: var(--space-3);
    padding-top: var(--space-4);
  }

  .site-footer__brand {
    grid-column: span 6;
  }

  .site-footer__group {
    grid-column: span 2;
  }

  .site-footer__contact {
    grid-column: span 6;
  }
}

@media (max-width: 640px) {
  .container {
    padding-inline: var(--space-2);
  }

  .site-footer__top {
    grid-template-columns: 1fr;
    gap: var(--space-3);
  }

  .site-footer__brand,
  .site-footer__group,
  .site-footer__contact {
    grid-column: 1;
  }

  .site-footer__bottom-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .research-board {
    padding: var(--space-3);
  }

  .btn {
    width: 100%;
  }
}

/* ---------- 17. 动效偏好 ---------- */
@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;
  }

  .js [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .site-header {
    transition: none;
  }

  .site-nav,
  .site-nav__toggle-bar,
  .site-header__progress {
    transition: none;
  }
}