/* ==========================================================================
   牛宝主站 · 共享样式 /assets/site.css
   手册式界面：纸色画布 + 88px 刻度网格 + 等宽编号 + 琥珀橙 / 青蓝状态
   ========================================================================== */

/* 1. Reset ---------------------------------------------------------------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body { margin: 0; }

h1, h2, h3, h4, h5, p, ul, ol, figure, blockquote, dl, dd { margin: 0; }

ul, ol { padding: 0; list-style: none; }

button, input, select, textarea { font: inherit; color: inherit; }

button { background: none; border: 0; }

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

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

table { border-collapse: collapse; width: 100%; }

:where(a, button, summary, [tabindex]):focus-visible {
  outline: 3px solid var(--amber);
  outline-offset: 3px;
}

/* 2. 变量 ---------------------------------------------------------------- */
:root {
  --paper: #FBF6EC;
  --sand: #F1E4CF;
  --ink: #1E1712;
  --brown: #5A3D27;
  --gold: #B07A2F;
  --amber: #F07A13;
  --teal: #147D8C;
  --teal-lift: #4FC3D1; /* 深青底上的青蓝状态点提亮值 */
  --clay: #D9BE9B;
  --deep: #0F3F46;
  --white: #FFFDF8;

  --font-display: 'Noto Sans SC', 'Source Han Sans SC', 'PingFang SC', sans-serif;
  --font-body: 'Noto Sans SC', 'Source Han Sans SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'IBM Plex Mono', 'JetBrains Mono', 'SFMono-Regular', Consolas, monospace;

  --shell: 1240px;
  --shell-wide: 1440px;
  --gutter: clamp(16px, 4vw, 48px);
  --rail: 88px;

  --radius-lg: 32px;
  --radius-md: 24px;
  --radius-sm: 14px;
  --radius-pill: 999px;

  --ease: cubic-bezier(0.2, 0.8, 0.2, 1);
  --dur: 200ms;
  --dur-slow: 240ms;

  --line: 1px solid var(--clay);
  --line-soft: 1px solid rgba(217, 190, 155, 0.6);
}

/* 3. 基础排版 ------------------------------------------------------------ */
body {
  background-color: var(--paper);
  background-image: linear-gradient(90deg, rgba(217, 190, 155, 0.26) 1px, transparent 1px);
  background-size: 88px 100%;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  overflow-wrap: break-word;
  word-break: break-word;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection {
  background: var(--amber);
  color: var(--ink);
}

.nb-main {
  position: relative;
  z-index: 1;
  display: block;
}

.nb-shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

/* 4. 文字层级 ------------------------------------------------------------ */
.nb-kicker {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.14em;
  line-height: 1.4;
  color: var(--brown);
}

.nb-h1 {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(40px, 7vw, 96px);
  line-height: 1.02;
  letter-spacing: -0.01em;
}

.nb-h2 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(28px, 3.6vw, 44px);
  line-height: 1.14;
  letter-spacing: -0.005em;
}

.nb-h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 20px;
  line-height: 1.35;
}

.nb-lead {
  max-width: 60ch;
  font-size: clamp(17px, 1.8vw, 20px);
  line-height: 1.7;
  color: var(--brown);
}

.nb-num {
  font-family: var(--font-mono);
  font-weight: 700;
  letter-spacing: 0.02em;
  font-variant-numeric: tabular-nums;
}

.nb-prose {
  max-width: 68ch;
  font-size: 17px;
  line-height: 1.75;
}

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

.nb-prose a {
  color: var(--brown);
  padding-bottom: 2px;
  background-image: linear-gradient(var(--amber), var(--amber));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0 2px;
  transition: background-size 220ms var(--ease), color var(--dur) var(--ease);
}

.nb-prose a:hover {
  color: var(--ink);
  background-size: 100% 2px;
}

.nb-note {
  padding: 4px 0 4px 18px;
  border-left: 3px solid var(--gold);
  font-size: 15px;
  line-height: 1.7;
  color: var(--brown);
}

/* 5. 栅格 ---------------------------------------------------------------- */
.nb-grid {
  display: grid;
  gap: clamp(20px, 3vw, 36px);
}

.nb-grid--split { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); }

.nb-grid--rail { grid-template-columns: var(--rail) minmax(0, 1fr); }

/* 6. 按钮 ---------------------------------------------------------------- */
.nb-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border: 1px solid var(--brown);
  border-radius: var(--radius-pill);
  background: transparent;
  color: var(--brown);
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1.2;
  white-space: nowrap;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease),
              color var(--dur) var(--ease),
              border-color var(--dur) var(--ease);
}

.nb-btn:hover {
  background: var(--brown);
  border-color: var(--brown);
  color: var(--paper);
}

.nb-btn--solid {
  background: var(--brown);
  border-color: var(--brown);
  color: var(--paper);
}

.nb-btn--solid:hover {
  background: var(--amber);
  border-color: var(--amber);
  color: var(--ink);
}

.nb-btn--sm {
  padding: 9px 16px;
  font-size: 13px;
}

/* 7. 面包屑 -------------------------------------------------------------- */
.nb-crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--brown);
}

.nb-crumbs a {
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.nb-crumbs a:hover {
  color: var(--ink);
  border-bottom-color: var(--amber);
}

.nb-crumbs__sep { color: var(--clay); }

/* 8. 图片容器（页面阶段放图） -------------------------------------------- */
.nb-figure {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.nb-figure__media {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: var(--line);
  border-radius: var(--radius-md);
  background: var(--sand);
}

.nb-figure__media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.nb-figure__tag {
  position: absolute;
  top: 12px;
  left: 12px;
  z-index: 1;
  padding: 5px 12px;
  border-radius: var(--radius-pill);
  background: rgba(251, 246, 236, 0.94);
  color: var(--brown);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  line-height: 1.6;
}

.nb-figure__caption {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  line-height: 1.6;
  color: var(--brown);
}
</br>
.nb-figure--tall .nb-figure__media { aspect-ratio: 4 / 5; }
.nb-figure--square .nb-figure__media { aspect-ratio: 1 / 1; }
.nb-figure--wide .nb-figure__media { aspect-ratio: 21 / 9; }

/* 9. 状态与胶囊 ----------------------------------------------------------- */
.nb-status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  line-height: 1.6;
  color: var(--brown);
}

.nb-status__dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--teal);
}

.nb-status--warn .nb-status__dot { background: var(--amber); }
.nb-status--done .nb-status__dot { background: var(--teal); }

/* 10. 页头 --------------------------------------------------------------- */
.nb-skip {
  position: fixed;
  top: -80px;
  left: 16px;
  z-index: 200;
  padding: 12px 22px;
  border-radius: var(--radius-pill);
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  transition: top var(--dur) var(--ease);
}

.nb-skip:focus { top: 16px; }

.nb-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: transparent;
  border-bottom: 1px solid transparent;
  transition: background-color var(--dur-slow) var(--ease),
              border-color var(--dur-slow) var(--ease),
              box-shadow var(--dur-slow) var(--ease);
}

.nb-header[data-scrolled="true"] {
  background-color: rgba(251, 246, 236, 0.96);
  border-bottom-color: var(--clay);
  box-shadow: 0 18px 40px -34px rgba(30, 23, 18, 0.55);
}

.nb-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 3px;
  pointer-events: none;
}

.nb-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--amber), var(--teal));
  transition: width 100ms linear;
}

.nb-header__inner {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: clamp(16px, 3vw, 40px);
  width: 100%;
  max-width: var(--shell-wide);
  margin-inline: auto;
  padding: 16px var(--gutter);
}

/* 品牌 */
.nb-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 4px 6px 4px 0;
  border-radius: var(--radius-pill);
}

.nb-brand__mark {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border: 1px solid var(--gold);
  border-radius: var(--radius-sm);
  background: var(--brown);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.06em;
  line-height: 1;
  transition: background-color var(--dur) var(--ease),
              border-color var(--dur) var(--ease),
              color var(--dur) var(--ease);
}

.nb-brand:hover .nb-brand__mark {
  background: var(--amber);
  border-color: var(--amber);
  color: var(--ink);
}

.nb-brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.nb-brand__name {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 800;
  letter-spacing: 0.04em;
  color: var(--ink);
}

.nb-brand__tagline {
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--brown);
}

/* 导航 */
.nb-nav {
  display: flex;
  justify-content: flex-end;
}

.nb-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2vw, 30px);
}

.nb-nav__link {
  position: relative;
  display: inline-block;
  padding: 10px 2px;
  font-size: 14px;
  letter-spacing: 0.06em;
  line-height: 1.2;
  color: var(--ink);
  transition: color var(--dur) var(--ease);
}

.nb-nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 4px;
  height: 2px;
  background: var(--amber);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 220ms var(--ease);
}

.nb-nav__link:hover { color: var(--brown); }
.nb-nav__link:hover::after { transform: scaleX(1); }

.nb-nav__link[aria-current="page"] {
  color: var(--brown);
  font-weight: 700;
}

.nb-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--amber);
}

.nb-nav__foot { display: none; }

.nb-nav__utility {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--brown);
}

/* 头部右侧 */
.nb-header__actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

.nb-header__utility {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--brown);
  white-space: nowrap;
}

/* 移动导航按钮 */
.nb-nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 10px 16px;
  border: 1px solid var(--brown);
  border-radius: var(--radius-pill);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  cursor: pointer;
  transition: border-color var(--dur) var(--ease),
              background-color var(--dur) var(--ease);
}

.nb-nav-toggle:hover { border-color: var(--amber); }

.nb-nav-toggle[aria-expanded="true"] {
  background: var(--sand);
  border-color: var(--amber);
}

.nb-nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  gap: 4px;
  width: 18px;
}

.nb-nav-toggle__bars span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--brown);
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.nb-nav-toggle[aria-expanded="true"] .nb-nav-toggle__bars span:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.nb-nav-toggle[aria-expanded="true"] .nb-nav-toggle__bars span:nth-child(2) {
  opacity: 0;
}

.nb-nav-toggle[aria-expanded="true"] .nb-nav-toggle__bars span:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

.nb-nav-toggle__label { line-height: 1; }

/* 11. 页脚 --------------------------------------------------------------- */
.nb-footer {
  position: relative;
  margin-top: clamp(64px, 9vw, 132px);
  overflow: hidden;
  background: var(--deep);
  color: var(--paper);
}

.nb-footer::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: linear-gradient(90deg, rgba(251, 246, 236, 0.07) 1px, transparent 1px);
  background-size: 88px 100%;
  pointer-events: none;
}

.nb-footer__inner {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding: clamp(44px, 6vw, 76px) var(--gutter) 0;
}

.nb-footer__masthead {
  display: grid;
  grid-template-columns: minmax(260px, 1fr) minmax(0, 1.7fr);
  gap: clamp(32px, 5vw, 72px);
  padding-bottom: clamp(32px, 4vw, 52px);
  border-bottom: 1px solid rgba(251, 246, 236, 0.18);
}

.nb-footer__brand {
  display: flex;
  flex-direction: column;
  gap: 12px;
  max-width: 34ch;
}

.nb-footer__mark {
  display: grid;
  place-items: center;
  width: 52px;
  height: 52px;
  border: 1px solid var(--gold);
  border-radius: 16px;
  color: var(--gold);
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1;
}

.nb-footer__name {
  font-family: var(--font-display);
  font-size: 28px;
  font-weight: 800;
  letter-spacing: 0.04em;
  line-height: 1.2;
  color: var(--white);
}

.nb-footer__summary {
  font-size: 14px;
  line-height: 1.8;
  color: rgba(251, 246, 236, 0.74);
}

.nb-footer__cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(20px, 3vw, 40px);
}

.nb-footer__col { min-width: 0; }

.nb-footer__col-title {
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.16em;
  line-height: 1.5;
  color: var(--gold);
}

.nb-footer__links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.nb-footer__link {
  display: inline-block;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  font-size: 14px;
  line-height: 1.6;
  color: rgba(251, 246, 236, 0.86);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.nb-footer__link:hover {
  color: var(--white);
  border-bottom-color: var(--amber);
}

.nb-footer__link[aria-current="page"] { color: var(--amber); }

.nb-footer__contact {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(20px, 3vw, 40px);
  padding-block: clamp(26px, 3.5vw, 42px);
  border-bottom: 1px solid rgba(251, 246, 236, 0.18);
}

.nb-footer__contact-row {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
}

.nb-footer__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  line-height: 1.5;
  color: var(--gold);
}

.nb-footer__value {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.7;
  color: var(--white);
}

/* 复制按钮 */
.nb-copy {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 1px solid rgba(251, 246, 236, 0.3);
  border-radius: var(--radius-pill);
  background: transparent;
  color: rgba(251, 246, 236, 0.78);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  line-height: 1.6;
  cursor: pointer;
  transition: border-color var(--dur) var(--ease),
              color var(--dur) var(--ease),
              background-color var(--dur) var(--ease);
}

.nb-copy::before {
  content: "";
  display: block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--gold);
  transition: background-color var(--dur) var(--ease);
}

.nb-copy:hover {
  border-color: var(--amber);
  color: var(--white);
}

.nb-copy[data-copied="true"] {
  border-color: var(--teal-lift);
  background: rgba(20, 125, 140, 0.24);
  color: var(--white);
}

.nb-copy[data-copied="true"]::before { background: var(--teal-lift); }

.nb-footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px 32px;
  padding-block: 22px 30px;
}

.nb-footer__legal {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  line-height: 1.7;
  color: rgba(251, 246, 236, 0.66);
}

.nb-footer__note {
  max-width: 56ch;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  line-height: 1.8;
  color: rgba(251, 246, 236, 0.56);
}

/* 12. 响应式 ------------------------------------------------------------- */
@media (max-width: 1180px) {
  .nb-header__utility { display: none; }
  .nb-nav__list { gap: 14px; }
  .nb-nav__link { font-size: 13px; }
}

@media (max-width: 1080px) {
  .nb-grid--split,
  .nb-grid--rail { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 980px) {
  .nb-header__inner {
    grid-template-columns: minmax(0, 1fr) auto;
    padding-block: 12px;
    gap: 12px;
  }

  .nb-header__actions { display: none; }

  .nb-nav-toggle { display: inline-flex; }

  .nb-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: block;
    margin: 0 var(--gutter);
    padding: 0 18px;
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    visibility: hidden;
    border: 1px solid transparent;
    border-radius: var(--radius-md);
    background: var(--white);
    box-shadow: 0 30px 70px -40px rgba(30, 23, 18, 0.6);
    transition: max-height 260ms var(--ease),
                opacity 200ms var(--ease),
                padding 260ms var(--ease),
                border-color 200ms var(--ease),
                visibility 0s linear 260ms;
  }

  .nb-nav[data-open] {
    max-height: min(74vh, 620px);
    overflow-y: auto;
    opacity: 1;
    visibility: visible;
    padding: 18px;
    border-color: var(--clay);
    transition-delay: 0s;
  }

  .nb-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nb-nav__link {
    display: block;
    padding: 14px 2px;
    border-bottom: 1px solid var(--clay);
    font-size: 17px;
    letter-spacing: 0.04em;
  }

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

  .nb-nav__link:hover { color: var(--amber); }

  .nb-nav__link[aria-current="page"] {
    color: var(--amber);
    padding-left: 18px;
    position: relative;
  }

  .nb-nav__link[aria-current="page"]::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    width: 8px;
    height: 8px;
    margin-top: -4px;
    border-radius: 50%;
    background: var(--amber);
    transform: none;
  }

  .nb-nav__foot {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    padding: 18px 2px 4px;
  }

  .nb-footer__masthead {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
  }

  .nb-footer__contact { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 720px) {
  body {
    background-image: none;
    font-size: 16px;
  }

  .nb-brand__tagline { display: none; }

  .nb-brand__mark {
    width: 40px;
    height: 40px;
    font-size: 13px;
  }

  .nb-brand__name { font-size: 18px; }

  .nb-footer::before { background-size: 56px 100%; }

  .nb-footer__cols {
    grid-template-columns: minmax(0, 1fr);
    gap: 26px;
  }

  .nb-footer__bottom {
    display: block;
    padding-bottom: 26px;
  }

  .nb-footer__note { margin-top: 10px; }
}

@media (max-width: 420px) {
  .nb-nav-toggle__label { display: none; }
}

/* 13. 减弱动效 ----------------------------------------------------------- */
@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;
    transition-delay: 0ms !important;
    scroll-behavior: auto !important;
  }

  .nb-progress__bar { transition: none !important; }
}