/* ==========================================================================
   海博体育看台 — 共享样式 /assets/site.css
   视觉体系：蓝图坐标网格 × 夜间看台灯束
   ========================================================================== */

/* ---------- 01. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-rail) + var(--header-h) + 16px);
}

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

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

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

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}

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

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

:focus-visible {
  outline: 2px solid var(--c-cyan);
  outline-offset: 3px;
}

/* ---------- 02. 变量 ---------- */
:root {
  /* 品牌色 */
  --c-deep:      #061A2B;
  --c-stand:     #0B2C47;
  --c-night:     #123F5E;
  --c-cyan:      #37F2D6;
  --c-mint:      #A9FFF2;
  --c-coral:     #FF6B4A;
  --c-mist:      #F2F7FA;
  --c-graphite:  #0A0E12;
  --c-grid:      #2A4A63;
  --c-data:      #8FA6B8;

  /* 语义色 */
  --ink:         #F2F7FA;
  --ink-soft:    rgba(242, 247, 250, 0.82);
  --ink-dim:     rgba(242, 247, 250, 0.62);
  --line:        rgba(42, 74, 99, 0.9);
  --line-soft:   rgba(42, 74, 99, 0.48);

  /* 字体 */
  --font-body: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB",
               "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", sans-serif;
  --font-mono: ui-monospace, "SF Mono", "Cascadia Mono", Menlo, Consolas,
               "Courier New", monospace;

  /* 尺度 */
  --container: 1360px;
  --gutter: clamp(18px, 4vw, 56px);
  --header-rail: 26px;
  --header-h: 84px;

  /* 动效 */
  --ease: cubic-bezier(0.22, 0.68, 0, 1);
  --dur: 0.22s;
}

/* ---------- 03. 基础排版 ---------- */
body {
  min-height: 100vh;
  overflow-x: clip;
  background-color: var(--c-deep);
  background-image:
    linear-gradient(to right, rgba(42, 74, 99, 0.28) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(42, 74, 99, 0.28) 1px, transparent 1px);
  background-size: 88px 88px;
  background-position: center top;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.01em;
}

::selection {
  background: var(--c-cyan);
  color: var(--c-deep);
}

/* ---------- 04. 工具类 ---------- */
.sb-container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

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

.sb-visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.sb-mono {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  font-variant-numeric: tabular-nums;
}

.sb-hairline {
  height: 1px;
  border: 0;
  background: var(--line);
}

.sb-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--c-cyan);
}

.sb-eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  background: currentColor;
  flex: 0 0 auto;
}

.sb-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 9px;
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--c-data);
  background: rgba(11, 44, 71, 0.45);
  white-space: nowrap;
}

.sb-tag--live {
  border-color: var(--c-coral);
  color: var(--c-coral);
  background: rgba(255, 107, 74, 0.1);
}

/* ---------- 05. Skip link ---------- */
.skip-link {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 400;
  padding: 14px 24px;
  background: var(--c-cyan);
  color: var(--c-deep);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  transform: translateY(-120%);
  transition: transform 0.18s var(--ease);
}

.skip-link:focus {
  transform: translateY(0);
  outline: 2px solid var(--c-deep);
  outline-offset: -6px;
}

/* ---------- 06. 页头 ---------- */
.sb-header {
  position: sticky;
  top: 0;
  z-index: 120;
  background: rgba(6, 26, 43, 0.96);
  border-bottom: 1px solid var(--line);
  color: var(--ink);
}

/* 刻度横条 */
.sb-header__rail {
  display: flex;
  align-items: center;
  gap: 16px;
  height: var(--header-rail);
  padding-inline: var(--gutter);
  overflow: hidden;
  border-bottom: 1px solid var(--line-soft);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--c-data);
  white-space: nowrap;
  transition: height 0.26s var(--ease), opacity 0.18s var(--ease),
              border-color 0.26s var(--ease);
}

.sb-header__rail-mark {
  color: var(--c-cyan);
  flex: 0 0 auto;
}

.sb-header__rail-line {
  flex: 1 1 auto;
  height: 1px;
  min-width: 24px;
  background: linear-gradient(90deg, var(--c-cyan), transparent 72%);
  opacity: 0.65;
}

.sb-header__rail-coord {
  flex: 0 0 auto;
}

/* 主栏 */
.sb-header__grid {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2.4vw, 40px);
  height: var(--header-h);
  transition: height 0.26s var(--ease);
}

.sb-header[data-scrolled] .sb-header__rail {
  height: 0;
  opacity: 0;
  border-bottom-color: transparent;
}

.sb-header[data-scrolled] .sb-header__grid {
  height: 62px;
}

/* 品牌 */
.sb-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  padding-block: 6px;
}

.sb-brand__mark {
  position: relative;
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  flex: 0 0 auto;
  border: 1px solid var(--c-cyan);
  color: var(--c-cyan);
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.sb-brand__mark::after {
  content: "";
  position: absolute;
  inset: 3px;
  border: 1px solid rgba(55, 242, 214, 0.28);
  pointer-events: none;
}

.sb-brand__mark svg {
  width: 18px;
  height: 18px;
}

.sb-brand:hover .sb-brand__mark,
.sb-brand:focus-visible .sb-brand__mark {
  background: var(--c-cyan);
  color: var(--c-deep);
}

.sb-brand__text {
  display: block;
  min-width: 0;
}

.sb-brand__name {
  display: block;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.05em;
  line-height: 1.25;
  white-space: nowrap;
}

.sb-brand__meta {
  display: block;
  margin-top: 2px;
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--c-data);
  white-space: nowrap;
  transition: opacity var(--dur) var(--ease);
}

/* 主导航（桌面） */
.sb-nav {
  flex: 1 1 auto;
  display: flex;
  justify-content: center;
  min-width: 0;
}

.sb-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(2px, 1vw, 18px);
}

.sb-nav__item { flex: 0 0 auto; }

.sb-nav__link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 8px 6px;
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--ink-soft);
  white-space: nowrap;
  transition: color var(--dur) var(--ease);
}

.sb-nav__index {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.14em;
  color: var(--c-data);
  transition: color var(--dur) var(--ease);
}

.sb-nav__link::after {
  content: "";
  position: absolute;
  left: 6px;
  right: 6px;
  bottom: 2px;
  height: 1px;
  background: var(--c-cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.2s var(--ease), background-color 0.2s var(--ease);
}

.sb-nav__link:hover,
.sb-nav__link:focus-visible {
  color: var(--c-cyan);
}

.sb-nav__link:hover .sb-nav__index,
.sb-nav__link:focus-visible .sb-nav__index {
  color: var(--c-cyan);
}

.sb-nav__link:hover::after,
.sb-nav__link:focus-visible::after {
  transform: scaleX(1);
}

.sb-nav__link[aria-current="page"] {
  color: var(--c-cyan);
}

.sb-nav__link[aria-current="page"] .sb-nav__index {
  color: var(--c-coral);
}

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

/* 操作区 */
.sb-header__actions {
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.4vw, 20px);
  flex: 0 0 auto;
}

.sb-header__utility {
  display: flex;
  align-items: center;
  gap: 14px;
}

.sb-header__utility-link {
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  color: var(--c-data);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.sb-header__utility-link:hover,
.sb-header__utility-link:focus-visible {
  color: var(--c-mint);
  border-bottom-color: var(--c-mint);
}

/* 移动导航按钮 */
.sb-nav-toggle {
  display: none;
  flex: 0 0 auto;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  border: 1px solid var(--line);
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.sb-nav-toggle__bar {
  display: block;
  width: 18px;
  height: 1.5px;
  background: var(--c-cyan);
  transition: transform 0.24s var(--ease), opacity 0.18s var(--ease),
              background-color 0.18s var(--ease);
}

.sb-nav-toggle:hover { border-color: var(--c-cyan); }

.sb-nav-toggle[aria-expanded="true"] { border-color: var(--c-coral); }

.sb-nav-toggle[aria-expanded="true"] .sb-nav-toggle__bar {
  background: var(--c-coral);
}

.sb-nav-toggle[aria-expanded="true"] .sb-nav-toggle__bar:nth-child(1) {
  transform: translateY(6.5px) rotate(45deg);
}

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

.sb-nav-toggle[aria-expanded="true"] .sb-nav-toggle__bar:nth-child(3) {
  transform: translateY(-6.5px) rotate(-45deg);
}

/* 滚动进度 */
.sb-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  z-index: 2;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--c-cyan), var(--c-coral));
  transition: width 0.1s linear;
}

/* ---------- 07. 按钮 ---------- */
.sb-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 11px 20px;
  border: 1px solid var(--c-cyan);
  background: transparent;
  color: var(--c-cyan);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  white-space: nowrap;
  transition: background-color var(--dur) var(--ease),
              color var(--dur) var(--ease),
              border-color var(--dur) var(--ease);
}

.sb-btn--primary {
  background: var(--c-cyan);
  border-color: var(--c-cyan);
  color: var(--c-deep);
}

.sb-btn--primary:hover,
.sb-btn--primary:focus-visible {
  background: var(--c-mint);
  border-color: var(--c-mint);
  color: var(--c-deep);
}

.sb-btn--ghost {
  border-color: var(--line);
  color: var(--ink);
}

.sb-btn--ghost:hover,
.sb-btn--ghost:focus-visible {
  background: var(--c-mint);
  border-color: var(--c-mint);
  color: var(--c-deep);
}

/* ---------- 08. 页脚 ---------- */
.sb-footer {
  position: relative;
  overflow: hidden;
  border-top: 1px solid var(--c-grid);
  background: var(--c-graphite);
  color: var(--ink);
}

.sb-footer__grid {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(42, 74, 99, 0.55) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(42, 74, 99, 0.55) 1px, transparent 1px);
  background-size: 88px 88px;
  opacity: 0.34;
  -webkit-mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.95), transparent 82%);
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.95), transparent 82%);
}

.sb-footer__inner {
  position: relative;
  z-index: 1;
  padding-block: clamp(48px, 7vw, 88px) 0;
}

.sb-footer__top {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.35fr) minmax(0, 1.15fr);
  gap: clamp(28px, 4vw, 64px) clamp(24px, 3.5vw, 48px);
  align-items: start;
}

.sb-footer__coord {
  display: inline-block;
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--c-cyan);
}

.sb-footer__brandline {
  max-width: 34ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-soft);
}

.sb-footer__mark {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 28px;
}

.sb-footer__mark-line {
  flex: 1 1 auto;
  height: 1px;
  min-width: 20px;
  background: linear-gradient(90deg, var(--c-cyan), transparent);
}

.sb-footer__mark-text {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.26em;
  color: var(--c-data);
  white-space: nowrap;
}

.sb-footer__cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(16px, 2vw, 28px);
}

.sb-footer__col-title {
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 400;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--c-data);
}

.sb-footer__link {
  display: inline-block;
  padding-block: 6px;
  border-bottom: 1px solid transparent;
  font-size: 14px;
  color: var(--ink-soft);
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.sb-footer__link:hover,
.sb-footer__link:focus-visible {
  color: var(--c-cyan);
  border-bottom-color: var(--c-cyan);
}

.sb-contact-row {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 10px;
  padding-block: 9px;
  border-bottom: 1px solid var(--line-soft);
}

.sb-contact-row__key {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  color: var(--c-data);
  white-space: nowrap;
}

.sb-contact-row__val {
  min-width: 0;
  font-size: 13px;
  line-height: 1.5;
  color: var(--ink-soft);
  word-break: break-word;
}

.sb-copy {
  padding: 4px 8px;
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.16em;
  color: var(--c-data);
  white-space: nowrap;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.sb-copy:hover,
.sb-copy:focus-visible {
  color: var(--c-cyan);
  border-color: var(--c-cyan);
}

.sb-copy[data-copied] {
  color: var(--c-coral);
  border-color: var(--c-coral);
}

.sb-footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px clamp(14px, 3vw, 34px);
  margin-top: clamp(36px, 5vw, 64px);
  padding-block: 22px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--c-data);
}

.sb-footer__copy,
.sb-footer__icp,
.sb-footer__hours {
  white-space: nowrap;
}

.sb-footer__legal-group {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(12px, 2vw, 24px);
  margin-left: auto;
}

.sb-footer__legal {
  border-bottom: 1px solid transparent;
  color: var(--c-data);
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.sb-footer__legal:hover,
.sb-footer__legal:focus-visible {
  color: var(--c-cyan);
  border-bottom-color: var(--c-cyan);
}

/* ---------- 09. 通用内容组件 ---------- */
.sb-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 18px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  color: var(--c-data);
}

.sb-breadcrumb a {
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.sb-breadcrumb a:hover,
.sb-breadcrumb a:focus-visible {
  color: var(--c-cyan);
  border-bottom-color: var(--c-cyan);
}

.sb-breadcrumb__sep {
  color: var(--c-grid);
}

.sb-breadcrumb [aria-current="page"] {
  color: var(--c-mint);
}

.sb-prose {
  max-width: 68ch;
  font-size: 17px;
  line-height: 1.78;
  color: var(--ink-soft);
}

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

.sb-prose h2 {
  margin-top: 2em;
  font-size: clamp(1.35rem, 2.2vw, 1.7rem);
  color: var(--ink);
}

.sb-prose h3 {
  margin-top: 1.7em;
  font-size: clamp(1.05rem, 1.6vw, 1.22rem);
  color: var(--ink);
}

.sb-prose strong { color: var(--c-mint); font-weight: 600; }

.sb-prose a {
  color: var(--c-cyan);
  border-bottom: 1px solid rgba(55, 242, 214, 0.42);
  transition: border-color 0.16s var(--ease);
}

.sb-prose a:hover,
.sb-prose a:focus-visible {
  border-bottom-color: var(--c-cyan);
}

.sb-panel--light {
  background: var(--c-mist);
  color: var(--c-graphite);
}

.sb-panel--light .sb-prose { color: rgba(10, 14, 18, 0.84); }

.sb-panel--light .sb-prose h2,
.sb-panel--light .sb-prose h3 { color: var(--c-graphite); }

.sb-panel--light .sb-prose strong { color: var(--c-stand); }

.sb-panel--light .sb-eyebrow { color: var(--c-stand); }

.sb-panel--light .sb-breadcrumb,
.sb-panel--light .sb-breadcrumb a { color: rgba(10, 14, 18, 0.6); }

.sb-grid {
  display: grid;
  gap: clamp(16px, 2.4vw, 32px);
}

.sb-grid--12 {
  grid-template-columns: repeat(12, minmax(0, 1fr));
}

/* 图片容器基础规则（共享头尾不放图，页面阶段复用） */
.sb-figure {
  position: relative;
  display: block;
  margin: 0;
  border: 1px solid var(--line);
  background: var(--c-night);
  overflow: hidden;
}

.sb-figure__media {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background-color: var(--c-stand);
  background-image:
    linear-gradient(to right, rgba(42, 74, 99, 0.65) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(42, 74, 99, 0.65) 1px, transparent 1px);
  background-size: 32px 32px;
}

.sb-figure__media > img,
.sb-figure__media > picture,
.sb-figure__media > svg,
.sb-figure__media > video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.sb-figure__media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(135deg, rgba(55, 242, 214, 0.12), transparent 55%),
    linear-gradient(to top, rgba(6, 26, 43, 0.78), transparent 62%);
}

.sb-figure__media[data-placeholder]::before {
  content: attr(data-placeholder);
  position: absolute;
  right: 12px;
  bottom: 10px;
  z-index: 1;
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(169, 255, 242, 0.72);
}

.sb-figure__cap {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 14px;
  border-top: 1px solid var(--line);
  background: rgba(11, 44, 71, 0.62);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--c-data);
}

.sb-figure__cap::before {
  content: "FIG.";
  flex: 0 0 auto;
  color: var(--c-cyan);
}

.sb-figure--wide .sb-figure__media { aspect-ratio: 21 / 9; }
.sb-figure--tall .sb-figure__media { aspect-ratio: 3 / 4; }
.sb-figure--square .sb-figure__media { aspect-ratio: 1 / 1; }

/* ---------- 10. 显现 ---------- */
.sb-js [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.3s var(--ease), transform 0.3s var(--ease);
}

.sb-js [data-reveal="in"] {
  opacity: 1;
  transform: none;
}

/* ---------- 11. 响应式 ---------- */
@media (max-width: 1120px) {
  .sb-header[data-scrolled] .sb-header__rail {
    height: var(--header-rail);
    opacity: 1;
    border-bottom-color: var(--line-soft);
  }

  .sb-header[data-scrolled] .sb-header__grid {
    height: var(--header-h);
  }

  .sb-nav-toggle { display: flex; }

  .sb-header__utility { display: none; }

  .sb-header__actions { margin-left: auto; }

  .sb-nav {
    position: fixed;
    inset: 0;
    z-index: 110;
    display: block;
    padding: calc(var(--header-rail) + var(--header-h) + 26px) var(--gutter) 64px;
    overflow-y: auto;
    background-color: var(--c-stand);
    background-image:
      linear-gradient(to right, rgba(42, 74, 99, 0.55) 1px, transparent 1px),
      linear-gradient(to bottom, rgba(42, 74, 99, 0.55) 1px, transparent 1px);
    background-size: 64px 64px;
    border-top: 1px solid var(--line);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-10px);
    transition: opacity 0.2s var(--ease), transform 0.24s var(--ease),
                visibility 0.2s var(--ease);
  }

  .sb-nav[data-open] {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
  }

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

  .sb-nav__link {
    display: flex;
    align-items: baseline;
    gap: 12px;
    padding: 18px 4px;
    border-bottom: 1px solid var(--line-soft);
    font-size: 19px;
    font-weight: 600;
    color: var(--ink);
  }

  .sb-nav__index {
    font-size: 10px;
    color: var(--c-cyan);
  }

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

  .sb-nav__link[aria-current="page"] { color: var(--c-coral); }

  .sb-nav__link[aria-current="page"] .sb-nav__index { color: var(--c-coral); }

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

  .sb-footer__brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 860px) {
  .sb-grid--12 {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

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

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

@media (max-width: 720px) {
  body { background-size: 64px 64px; }

  .sb-brand__mark { width: 32px; height: 32px; }

  .sb-brand__meta { display: none; }

  .sb-brand__name { font-size: 14px; }

  .sb-header__actions .sb-btn {
    padding: 9px 13px;
    font-size: 10px;
    letter-spacing: 0.12em;
  }

  .sb-nav__link { font-size: 17px; }

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

  .sb-contact-row {
    grid-template-columns: 64px minmax(0, 1fr) auto;
  }

  .sb-footer__legal-group {
    margin-left: 0;
    width: 100%;
  }
}

@media (max-width: 480px) {
  .sb-header__actions .sb-btn { display: none; }

  .sb-grid--12 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

/* ---------- 12. 降低动效 ---------- */
@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;
    scroll-behavior: auto !important;
  }

  .sb-js [data-reveal] {
    opacity: 1 !important;
    transform: none !important;
  }

  .sb-progress { transition: none; }
}