/* ==========================================================================
   北单指南 · 共享样式表  /assets/site.css
   气质：夜间航图 × 终端控制台
   ========================================================================== */

/* ---------- 0. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body,
h1, h2, h3, h4, h5, h6,
p, figure, blockquote, dl, dd, ul, ol, hr { margin: 0; }

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

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

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

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

button { background: none; border: 0; cursor: pointer; }

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

/* ---------- 1. 变量 ---------- */
:root {
  --nt-deep: #0A1428;
  --nt-night: #101F3C;
  --nt-hull: #1B3159;
  --nt-cyan: #4FD1C5;
  --nt-orange: #FF6B35;
  --nt-gold: #E8C46A;
  --nt-mist: #EAF2FF;
  --nt-silver: #9BB0D3;
  --nt-abyss: #060D1A;
  --nt-alert: #FF4D6D;

  --nt-line: rgba(155, 176, 211, 0.18);
  --nt-line-soft: rgba(155, 176, 211, 0.10);

  --nt-shell: min(1280px, calc(100% - 48px));
  --nt-header-h: 132px;

  --nt-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC",
             system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --nt-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
             "Liberation Mono", monospace;

  --nt-ease: cubic-bezier(0.22, 0.61, 0.36, 1);

  --nt-r-sm: 8px;
  --nt-r-md: 16px;
  --nt-r-lg: 28px;
  --nt-r-organic: 28px 8px 28px 8px;
}

/* ---------- 2. 页面基底 ---------- */
body {
  min-height: 100vh;
  background-color: var(--nt-deep);
  background-image:
    linear-gradient(rgba(155, 176, 211, 0.042) 1px, transparent 1px),
    linear-gradient(90deg, rgba(155, 176, 211, 0.042) 1px, transparent 1px);
  background-size: 96px 96px;
  background-position: -1px -1px;
  color: var(--nt-mist);
  font-family: var(--nt-sans);
  font-size: 1rem;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--nt-mist);
}

h1 { font-size: clamp(2.2rem, 6vw, 4.25rem); }
h2 { font-size: clamp(1.7rem, 4vw, 2.75rem); }
h3 { font-size: clamp(1.2rem, 2.2vw, 1.5rem); }

#main-content { scroll-margin-top: 150px; }

::selection {
  background: rgba(255, 107, 53, 0.32);
  color: var(--nt-mist);
}

:focus-visible {
  outline: 2px solid var(--nt-cyan);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 3. 跳转链接 ---------- */
.nt-skip {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  padding: 10px 20px;
  border-radius: 999px;
  background: var(--nt-orange);
  color: var(--nt-deep);
  font-weight: 700;
  font-size: 0.9375rem;
  transform: translateY(-180%);
  transition: transform 0.24s var(--nt-ease);
}

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

/* ---------- 4. 页头 ---------- */
.nt-header {
  position: sticky;
  top: 0;
  z-index: 90;
  background: linear-gradient(180deg, rgba(10, 20, 40, 0.97) 0%, rgba(10, 20, 40, 0.87) 100%);
  border-bottom: 1px solid var(--nt-line);
  transition: background 0.32s var(--nt-ease);
}

.nt-header__inner {
  width: var(--nt-shell);
  margin-inline: auto;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 20px;
  padding-block: 18px;
  transition: padding-block 0.32s var(--nt-ease);
}

.nt-header[data-condensed] .nt-header__inner { padding-block: 9px; }

.nt-header__side {
  display: flex;
  align-items: center;
  gap: 14px;
  min-width: 0;
}

.nt-header__side--start { justify-content: flex-start; }
.nt-header__side--end { justify-content: flex-end; }

.nt-header__cta { flex: 0 0 auto; }

/* 版本状态灯 */
.nt-status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px 6px 12px;
  border: 1px solid var(--nt-line);
  border-radius: 999px;
  background: rgba(27, 49, 89, 0.42);
  font-family: var(--nt-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--nt-silver);
  white-space: nowrap;
}

.nt-status__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--nt-cyan);
  box-shadow: 0 0 0 3px rgba(79, 209, 197, 0.16);
  animation: nt-pulse 2.6s var(--nt-ease) infinite;
}

.nt-status__key {
  font-family: var(--nt-sans);
  letter-spacing: 0.04em;
}

.nt-status__val {
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--nt-gold);
}

@keyframes nt-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.34; }
}

/* 刊名 */
.nt-brand {
  display: grid;
  justify-items: center;
  gap: 2px;
  padding-inline: 18px;
  text-align: center;
  white-space: nowrap;
}

.nt-brand__name {
  font-size: clamp(1.3rem, 2.3vw, 1.7rem);
  font-weight: 800;
  letter-spacing: 0.14em;
  margin-right: -0.14em;
  color: var(--nt-mist);
  transition: color 0.24s var(--nt-ease), font-size 0.32s var(--nt-ease);
}

.nt-brand:hover .nt-brand__name { color: var(--nt-orange); }

.nt-header[data-condensed] .nt-brand__name { font-size: 1.15rem; }

.nt-brand__note {
  font-family: var(--nt-mono);
  font-size: 0.625rem;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: rgba(155, 176, 211, 0.66);
  transition: opacity 0.28s var(--nt-ease);
}

.nt-header[data-condensed] .nt-brand__note { opacity: 0; }

/* 汉堡按钮 */
.nt-burger {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 9px 14px;
  border: 1px solid rgba(155, 176, 211, 0.34);
  border-radius: 999px;
  background: rgba(16, 31, 60, 0.5);
  color: var(--nt-mist);
  transition: color 0.22s var(--nt-ease), border-color 0.22s var(--nt-ease);
}

.nt-burger__box {
  display: grid;
  gap: 4px;
  width: 18px;
}

.nt-burger__bar {
  display: block;
  height: 2px;
  width: 100%;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.26s var(--nt-ease), opacity 0.18s linear;
}

.nt-burger__label {
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
}

.nt-header[data-open] .nt-burger {
  color: var(--nt-orange);
  border-color: var(--nt-orange);
}

.nt-header[data-open] .nt-burger__bar:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nt-header[data-open] .nt-burger__bar:nth-child(2) { opacity: 0; }
.nt-header[data-open] .nt-burger__bar:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* 栏目条 */
.nt-nav {
  width: var(--nt-shell);
  margin-inline: auto;
  border-top: 1px solid var(--nt-line-soft);
}

.nt-nav__list {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: clamp(8px, 2.6vw, 42px);
  padding: 10px 0 14px;
  transition: padding 0.32s var(--nt-ease);
}

.nt-header[data-condensed] .nt-nav__list { padding: 6px 0 9px; }

.nt-nav__item { position: relative; }

.nt-nav__link {
  position: relative;
  display: inline-block;
  padding: 6px 2px;
  font-size: 0.9375rem;
  letter-spacing: 0.06em;
  color: rgba(234, 242, 255, 0.78);
  transition: color 0.22s var(--nt-ease);
}

.nt-nav__link::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 0;
  width: 0;
  height: 2px;
  border-radius: 2px;
  background: var(--nt-cyan);
  transform: translateX(-50%);
  transition: width 0.26s var(--nt-ease), background 0.22s var(--nt-ease);
}

.nt-nav__link:hover { color: var(--nt-cyan); }
.nt-nav__link:hover::after { width: 62%; }

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

.nt-nav__link[aria-current="page"]::after {
  width: 100%;
  background: var(--nt-orange);
}

/* 阅读进度 */
.nt-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  overflow: hidden;
  pointer-events: none;
}

.nt-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--nt-cyan) 0%, var(--nt-orange) 72%, var(--nt-gold) 100%);
  transition: transform 0.12s linear;
}

/* ---------- 5. 页脚 ---------- */
.nt-footer {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  margin-top: clamp(64px, 9vw, 120px);
  padding: clamp(48px, 7vw, 88px) 0 28px;
  background: var(--nt-abyss);
  border-top: 1px solid var(--nt-line);
  color: var(--nt-silver);
}

.nt-footer__glow {
  position: absolute;
  z-index: -1;
  top: -140px;
  left: -100px;
  width: 460px;
  height: 460px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(79, 209, 197, 0.16), transparent 68%);
  pointer-events: none;
}

.nt-footer__side {
  position: absolute;
  top: 68px;
  right: 26px;
  writing-mode: vertical-rl;
  font-family: var(--nt-mono);
  font-size: 0.625rem;
  letter-spacing: 0.5em;
  text-transform: uppercase;
  color: rgba(155, 176, 211, 0.24);
  pointer-events: none;
  user-select: none;
}

.nt-footer__inner {
  width: var(--nt-shell);
  margin-inline: auto;
  display: grid;
  grid-template-columns: 1.15fr 1fr 1.35fr;
  gap: clamp(28px, 4vw, 64px);
  padding-bottom: clamp(30px, 4vw, 52px);
  border-bottom: 1px solid var(--nt-line-soft);
}

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

.nt-footer__brand {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  color: var(--nt-mist);
}

.nt-footer__version {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-top: 14px;
  padding: 6px 8px 6px 14px;
  border: 1px solid rgba(232, 196, 106, 0.34);
  border-radius: 999px;
  background: rgba(232, 196, 106, 0.06);
}

.nt-footer__version-val {
  font-family: var(--nt-mono);
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--nt-gold);
}

.nt-footer__icp {
  margin-top: 16px;
  font-family: var(--nt-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: rgba(155, 176, 211, 0.72);
}

.nt-footer__title {
  margin-bottom: 16px;
  font-family: var(--nt-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: rgba(155, 176, 211, 0.62);
}

.nt-footer__list { display: grid; gap: 11px; }

.nt-footer__list--links {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 11px 24px;
}

.nt-footer__item {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px 12px;
  font-size: 0.9375rem;
}

.nt-footer__item--note { display: block; }

.nt-footer__link {
  position: relative;
  font-size: 0.9375rem;
  color: rgba(234, 242, 255, 0.78);
  transition: color 0.2s var(--nt-ease);
}

.nt-footer__link::before {
  content: "";
  display: inline-block;
  width: 0;
  height: 1px;
  margin-right: 0;
  vertical-align: middle;
  background: var(--nt-cyan);
  transition: width 0.24s var(--nt-ease), margin-right 0.24s var(--nt-ease);
}

.nt-footer__link:hover { color: var(--nt-cyan); }

.nt-footer__link:hover::before {
  width: 14px;
  margin-right: 8px;
}

.nt-footer__label {
  flex: 0 0 auto;
  padding: 2px 8px;
  border: 1px solid var(--nt-line-soft);
  border-radius: 4px;
  font-family: var(--nt-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  color: rgba(155, 176, 211, 0.6);
}

.nt-footer__value {
  font-family: var(--nt-mono);
  font-size: 0.875rem;
  color: var(--nt-mist);
  word-break: break-all;
}

.nt-footer__note {
  display: block;
  max-width: 46ch;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: rgba(155, 176, 211, 0.68);
}

/* 复制按钮 */
.nt-copy {
  flex: 0 0 auto;
  padding: 4px 11px;
  border: 1px solid rgba(155, 176, 211, 0.3);
  border-radius: 999px;
  font-family: var(--nt-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  color: var(--nt-silver);
  transition: color 0.2s var(--nt-ease), border-color 0.2s var(--nt-ease), background 0.2s var(--nt-ease);
}

.nt-copy:hover {
  color: var(--nt-cyan);
  border-color: var(--nt-cyan);
  background: rgba(79, 209, 197, 0.1);
}

.nt-copy[data-copied] {
  color: var(--nt-deep);
  background: var(--nt-cyan);
  border-color: var(--nt-cyan);
}

/* 底栏 */
.nt-footer__bottom {
  width: var(--nt-shell);
  margin-inline: auto;
  padding-top: 22px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
}

.nt-footer__legal {
  font-family: var(--nt-mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  color: rgba(155, 176, 211, 0.6);
}

/* ---------- 6. 通用按钮 ---------- */
.nt-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 20px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1.2;
  white-space: nowrap;
  transition: color 0.22s var(--nt-ease), background 0.22s var(--nt-ease),
              border-color 0.22s var(--nt-ease), transform 0.22s var(--nt-ease);
}

.nt-btn--primary {
  background: var(--nt-orange);
  color: var(--nt-deep);
  font-weight: 700;
}

.nt-btn--primary:hover {
  background: #ff8459;
  transform: translateY(-1px);
}

.nt-btn--ghost {
  border-color: rgba(155, 176, 211, 0.34);
  background: rgba(16, 31, 60, 0.5);
  color: var(--nt-mist);
}

.nt-btn--ghost:hover {
  border-color: var(--nt-orange);
  background: rgba(255, 107, 53, 0.08);
  color: var(--nt-orange);
}

.nt-btn--quiet {
  border-color: rgba(79, 209, 197, 0.36);
  color: var(--nt-cyan);
}

.nt-btn--quiet:hover {
  border-color: var(--nt-cyan);
  background: rgba(79, 209, 197, 0.12);
}

/* ---------- 7. 布局骨架 ---------- */
.nt-shell {
  width: var(--nt-shell);
  margin-inline: auto;
}

.nt-section { padding: clamp(48px, 7vw, 96px) 0; }

.nt-band { position: relative; }
.nt-band--night { background: var(--nt-night); }
.nt-band--hull { background: var(--nt-hull); }
.nt-band--abyss { background: var(--nt-abyss); }

.nt-split {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: clamp(24px, 4vw, 64px);
  align-items: start;
}

.nt-split--wide { grid-template-columns: minmax(0, 4fr) minmax(0, 8fr); }

.nt-grid {
  display: grid;
  gap: clamp(16px, 2.4vw, 28px);
}

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

/* ---------- 8. 文字层级 ---------- */
.nt-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--nt-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--nt-cyan);
}

.nt-eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: currentColor;
}

.nt-num {
  display: block;
  font-family: var(--nt-mono);
  font-size: clamp(2.4rem, 5vw, 3.6rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: transparent;
  -webkit-text-stroke: 1px rgba(155, 176, 211, 0.42);
}

.nt-num--solid {
  color: var(--nt-gold);
  -webkit-text-stroke: 0;
}

.nt-lede {
  max-width: 62ch;
  font-size: clamp(1.0625rem, 1.6vw, 1.25rem);
  line-height: 1.8;
  color: rgba(234, 242, 255, 0.78);
}

.nt-note {
  font-family: var(--nt-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: rgba(155, 176, 211, 0.68);
}

.nt-vert {
  writing-mode: vertical-rl;
  font-family: var(--nt-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.34em;
  text-transform: uppercase;
  color: rgba(155, 176, 211, 0.5);
}

.nt-link {
  color: var(--nt-cyan);
  border-bottom: 1px solid rgba(79, 209, 197, 0.35);
  transition: color 0.2s var(--nt-ease), border-color 0.2s var(--nt-ease);
}

.nt-link:hover {
  color: var(--nt-orange);
  border-bottom-color: var(--nt-orange);
}

/* ---------- 9. 组件 ---------- */
.nt-card,
.nt-panel {
  position: relative;
  padding: clamp(20px, 2.4vw, 30px);
  border: 1px solid var(--nt-line);
  border-radius: var(--nt-r-md);
  background: linear-gradient(156deg, rgba(27, 49, 89, 0.72), rgba(16, 31, 60, 0.88));
  transition: border-color 0.24s var(--nt-ease), transform 0.24s var(--nt-ease),
              background 0.24s var(--nt-ease);
}

.nt-card:hover {
  border-color: rgba(79, 209, 197, 0.5);
  transform: translateY(-3px);
}

.nt-card--organic { border-radius: var(--nt-r-organic); }

.nt-card--accent {
  border-left: 3px solid var(--nt-orange);
}

.nt-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 12px;
  border: 1px solid var(--nt-line);
  border-radius: 999px;
  background: rgba(10, 20, 40, 0.5);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--nt-silver);
}

.nt-tag--cyan { color: var(--nt-cyan); border-color: rgba(79, 209, 197, 0.4); }
.nt-tag--gold { color: var(--nt-gold); border-color: rgba(232, 196, 106, 0.4); }
.nt-tag--alert { color: var(--nt-alert); border-color: rgba(255, 77, 109, 0.42); }

.nt-dot {
  flex: 0 0 auto;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: currentColor;
}

.nt-divider {
  height: 1px;
  border: 0;
  margin: clamp(24px, 4vw, 48px) 0;
  background: linear-gradient(90deg, transparent, var(--nt-line), transparent);
}

/* 面包屑 */
.nt-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 18px;
  font-family: var(--nt-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: rgba(155, 176, 211, 0.7);
}

.nt-breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.nt-breadcrumb__item + .nt-breadcrumb__item::before {
  content: "/";
  color: rgba(155, 176, 211, 0.4);
}

.nt-breadcrumb__link {
  color: rgba(234, 242, 255, 0.8);
  transition: color 0.2s var(--nt-ease);
}

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

.nt-breadcrumb__current { color: var(--nt-gold); }

/* 正文排版 */
.nt-prose {
  max-width: 74ch;
  font-size: 1.0625rem;
  line-height: 1.78;
  color: rgba(234, 242, 255, 0.86);
}

.nt-prose > * + * { margin-top: 1.1em; }

.nt-prose h2 {
  margin-top: 1.9em;
  font-size: clamp(1.5rem, 3vw, 2rem);
}

.nt-prose h3 { margin-top: 1.6em; }

.nt-prose ul,
.nt-prose ol {
  padding-left: 1.4em;
  list-style: disc;
}

.nt-prose ol { list-style: decimal; }

.nt-prose li + li { margin-top: 0.5em; }

.nt-prose a {
  color: var(--nt-cyan);
  border-bottom: 1px solid rgba(79, 209, 197, 0.4);
}

.nt-prose a:hover {
  color: var(--nt-orange);
  border-bottom-color: var(--nt-orange);
}

.nt-prose strong { color: var(--nt-mist); font-weight: 700; }

.nt-prose code {
  padding: 0.12em 0.45em;
  border: 1px solid var(--nt-line-soft);
  border-radius: 5px;
  background: rgba(27, 49, 89, 0.7);
  font-family: var(--nt-mono);
  font-size: 0.9em;
  color: var(--nt-gold);
}

.nt-prose blockquote {
  padding-left: 18px;
  border-left: 3px solid var(--nt-cyan);
  color: rgba(234, 242, 255, 0.72);
}

/* ---------- 10. 图片容器 ---------- */
.nt-media {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--nt-line);
  border-radius: var(--nt-r-md);
  background:
    linear-gradient(140deg, rgba(27, 49, 89, 0.92), rgba(10, 20, 40, 0.96));
  background-image:
    linear-gradient(rgba(79, 209, 197, 0.09) 1px, transparent 1px),
    linear-gradient(90deg, rgba(79, 209, 197, 0.09) 1px, transparent 1px);
  background-size: 34px 34px, 34px 34px, auto, auto;
}

.nt-media > img,
.nt-media > video,
.nt-media > svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.nt-media__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 14px 16px;
  font-family: var(--nt-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.12em;
  color: rgba(234, 242, 255, 0.82);
  background: linear-gradient(180deg, transparent, rgba(6, 13, 26, 0.88));
}

.nt-media--wide { aspect-ratio: 21 / 9; }
.nt-media--tall { aspect-ratio: 3 / 4; }
.nt-media--square { aspect-ratio: 1 / 1; }
.nt-media--organic { border-radius: var(--nt-r-organic); }

/* ---------- 11. 显现 ---------- */
html.nt-js [data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.48s var(--nt-ease), transform 0.48s var(--nt-ease);
}

html.nt-js [data-reveal].is-revealed {
  opacity: 1;
  transform: none;
}

/* ---------- 12. 响应式 ---------- */
@media (max-width: 1100px) {
  .nt-grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 1000px) {
  .nt-grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .nt-footer__inner { grid-template-columns: 1fr 1fr; }
  .nt-footer__col--contact { grid-column: 1 / -1; }
  .nt-footer__side { display: none; }
}

@media (max-width: 920px) {
  :root {
    --nt-shell: min(100%, calc(100% - 32px));
    --nt-header-h: 108px;
  }

  #main-content { scroll-margin-top: 130px; }

  .nt-header__inner {
    grid-template-columns: 1fr auto 1fr;
    gap: 10px;
    padding-block: 12px;
  }

  .nt-header[data-condensed] .nt-header__inner { padding-block: 8px; }

  .nt-status { display: none; }
  .nt-header__cta { display: none; }
  .nt-burger { display: inline-flex; }

  .nt-brand { padding-inline: 8px; }
  .nt-header[data-condensed] .nt-brand__note { opacity: 1; }

  .nt-nav {
    max-height: none;
    border-top-color: var(--nt-line-soft);
  }

  html.nt-js .nt-nav {
    max-height: 0;
    overflow: hidden;
    border-top-color: transparent;
    transition: max-height 0.34s var(--nt-ease), border-color 0.34s var(--nt-ease);
  }

  html.nt-js .nt-header[data-open] .nt-nav {
    max-height: 480px;
    border-top-color: var(--nt-line-soft);
  }

  .nt-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 6px 0 18px;
  }

  .nt-nav__item {
    border-bottom: 1px solid var(--nt-line-soft);
  }

  .nt-nav__item:last-child { border-bottom: 0; }

  .nt-nav__link {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 13px 6px;
    font-size: 1rem;
  }

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

  .nt-nav__link[aria-current="page"] {
    padding-inline: 12px;
    border-radius: 8px;
    background: rgba(255, 107, 53, 0.1);
  }

  .nt-split,
  .nt-split--wide { grid-template-columns: 1fr; }
}

@media (max-width: 700px) {
  .nt-grid--2,
  .nt-grid--3,
  .nt-grid--4 { grid-template-columns: 1fr; }

  .nt-section { padding: 40px 0; }

  .nt-footer { padding-top: 52px; }

  .nt-footer__inner {
    grid-template-columns: 1fr;
    gap: 34px;
  }

  .nt-footer__col--contact { grid-column: auto; }

  .nt-footer__list--links { gap: 11px 16px; }

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

/* ---------- 13. 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  html.nt-js [data-reveal],
  html.nt-js [data-reveal].is-revealed {
    opacity: 1 !important;
    transform: none !important;
  }
}