/* ============================================
   易倍体育EMC · 全站共享样式 /assets/site.css
   设计向量：深空蓝底 · 切角面板 · 地图索引
   ============================================ */

/* ---------- 0. CSS 变量 ---------- */
:root {
  --c-bg-primary: #0A1B2A;
  --c-bg-secondary: #0F3A4B;
  --c-bg-wine: #6A1B2A;
  --c-bg-indigo: #3D2D5E;
  --c-accent: #FF6B2C;
  --c-accent-alt: #00E5A0;
  --c-text: #F0F4F8;
  --c-text-muted: #8DA2B8;
  --c-text-bright: #FFFFFF;
  --c-data: #FFD166;

  --font-heading: Futura, 'Noto Sans SC', 'PingFang SC', sans-serif;
  --font-body: Inter, 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, monospace;

  --container-w: 1240px;
  --container-pad: 1.25rem;
  --header-h: 72px;

  --transition: 0.25s ease;
  --transition-slow: 0.5s ease;
  --chamfer: 12px;
}

/* ---------- 1. Reset / 基础 ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
}

@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--c-text);
  background-color: var(--c-bg-primary);
  background-image: radial-gradient(rgba(255, 107, 44, 0.05) 1px, transparent 1px);
  background-size: 32px 32px;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

ul,
ol {
  list-style: none;
}

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

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

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--c-text-bright);
  line-height: 1.3;
}

::selection {
  background: var(--c-accent);
  color: var(--c-bg-primary);
}

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

/* ---------- 2. 容器与工具类 ---------- */
.container {
  width: 100%;
  max-width: var(--container-w);
  margin-inline: auto;
  padding-inline: var(--container-pad);
}

.container-wide {
  width: 100%;
  max-width: calc(var(--container-w) + 80px);
  margin-inline: auto;
  padding-inline: var(--container-pad);
}

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

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 3000;
  padding: 8px 18px;
  background: var(--c-accent);
  color: var(--c-bg-primary);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.875rem;
  transform: translateY(-120%);
  transition: transform var(--transition);
  clip-path: polygon(8px 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%, 0 8px);
}

.skip-link:focus-visible {
  transform: translateY(0);
  outline: none;
}

/* ---------- 3. 通用按钮 ---------- */
.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.7rem 1.5rem;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.9rem;
  line-height: 1;
  letter-spacing: 0.02em;
  border: 1px solid transparent;
  cursor: pointer;
  user-select: none;
  clip-path: polygon(10px 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%, 0 10px);
  transition: transform var(--transition), box-shadow var(--transition), background-color var(--transition), color var(--transition);
}

.btn:hover {
  transform: translateY(-2px);
}

.btn:focus-visible {
  outline: none;
}

.btn:focus-visible::after {
  content: '';
  position: absolute;
  inset: 2px;
  border: 2px solid var(--c-accent-alt);
  pointer-events: none;
}

.btn-primary {
  background: var(--c-accent);
  color: var(--c-bg-primary);
}

.btn-primary:hover {
  background: #ff8140;
  box-shadow: 0 4px 18px rgba(255, 107, 44, 0.35);
}

.btn-outline {
  background: transparent;
  color: var(--c-accent-alt);
  border-color: var(--c-accent-alt);
}

.btn-outline:hover {
  background: var(--c-accent-alt);
  color: var(--c-bg-primary);
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.82rem;
}

.arrow-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.875rem;
  color: var(--c-accent);
  transition: gap var(--transition), color var(--transition);
}

.arrow-link:hover {
  gap: 10px;
  color: var(--c-accent-alt);
}

.arrow-link::after {
  content: '→';
  font-family: var(--font-mono);
}

/* ---------- 4. 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: linear-gradient(120deg, rgba(10, 27, 42, 0.98) 0%, rgba(15, 58, 75, 0.96) 70%, rgba(61, 45, 94, 0.92) 100%);
  border-bottom: 1px solid rgba(141, 162, 184, 0.2);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.site-header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--c-accent) 0%, var(--c-accent) 15%, var(--c-accent-alt) 15%, var(--c-accent-alt) 30%, transparent 30%);
  pointer-events: none;
}

.site-header::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, var(--c-accent) 0%, transparent 60%);
  opacity: 0.4;
  pointer-events: none;
}

.header-inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: 1rem;
  min-height: var(--header-h);
}

/* 品牌 */
.brand-logo {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  flex-shrink: 0;
}

.brand-logo-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  flex-shrink: 0;
  background: var(--c-accent);
  color: var(--c-bg-primary);
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: 1rem;
  letter-spacing: -0.02em;
  clip-path: polygon(8px 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%, 0 8px);
}

.brand-logo-name {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand-logo-name strong {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--c-text-bright);
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.brand-logo-name small {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  color: var(--c-text-muted);
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

/* 实时状态 */
.header-status {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border: 1px solid rgba(0, 229, 160, 0.3);
  border-radius: 999px;
  background: rgba(0, 229, 160, 0.07);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--c-accent-alt);
  letter-spacing: 0.08em;
  white-space: nowrap;
  flex-shrink: 0;
}

.status-text {
  color: inherit;
}

.status-dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--c-accent-alt);
  animation: status-pulse 2s ease-in-out infinite;
}

@keyframes status-pulse {
  0%, 100% { opacity: 1; box-shadow: 0 0 0 0 rgba(0, 229, 160, 0.4); }
  50% { opacity: 0.6; box-shadow: 0 0 0 5px rgba(0, 229, 160, 0); }
}

/* 导航 */
.site-nav {
  margin-left: auto;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.nav-link {
  position: relative;
  display: block;
  padding: 0.5rem 0.8rem;
  font-family: var(--font-heading);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--c-text);
  letter-spacing: 0.04em;
  white-space: nowrap;
  transition: color var(--transition);
}

.nav-link::after {
  content: '';
  position: absolute;
  left: 0.8rem;
  right: 0.8rem;
  bottom: 2px;
  height: 2px;
  background: var(--c-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.nav-link:hover {
  color: var(--c-text-bright);
}

.nav-link:hover::after {
  transform: scaleX(1);
}

.nav-link[aria-current="page"] {
  color: var(--c-accent);
}

.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--c-accent);
}

/* 头部右侧动作区 */
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

.pc-entry-btn {
  white-space: nowrap;
}

/* 移动导航按钮 */
.nav-toggle {
  position: relative;
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  border: 1px solid rgba(141, 162, 184, 0.3);
  border-radius: 2px;
  background: rgba(10, 27, 42, 0.6);
  clip-path: polygon(6px 0, 100% 0, 100% calc(100% - 6px), calc(100% - 6px) 100%, 0 100%, 0 6px);
}

.nav-toggle:focus-visible {
  outline: none;
}

.nav-toggle:focus-visible::after {
  content: '';
  position: absolute;
  inset: 2px;
  border: 2px solid var(--c-accent-alt);
  pointer-events: none;
}

.nav-toggle-line {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--c-text);
  border-radius: 1px;
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle:hover .nav-toggle-line {
  background: var(--c-accent);
}

/* ---------- 5. 面包屑 ---------- */
.breadcrumb {
  margin-bottom: 1.5rem;
}

.breadcrumb-list {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--c-text-muted);
}

.breadcrumb-item {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.breadcrumb-item + .breadcrumb-item::before {
  content: '/';
  color: var(--c-text-muted);
  opacity: 0.5;
}

.breadcrumb-item a {
  color: var(--c-accent);
  transition: color var(--transition);
}

.breadcrumb-item a:hover {
  color: var(--c-accent-alt);
}

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

/* ---------- 6. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: 4rem;
  background: linear-gradient(160deg, #071321 0%, #0A1B2A 50%, #0F1E2E 100%);
  border-top: 1px solid rgba(255, 107, 44, 0.25);
}

.site-footer::before {
  content: '';
  position: absolute;
  top: -1px;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, var(--c-accent) 30%, var(--c-accent-alt) 70%, transparent 100%);
}

.footer-inner {
  padding-block: 3rem 1.5rem;
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1.4fr;
  gap: 2.5rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px dashed rgba(141, 162, 184, 0.18);
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 1rem;
}

.footer-logo .brand-logo-mark {
  width: 38px;
  height: 38px;
  font-size: 0.9rem;
}

.footer-about {
  font-size: 0.9rem;
  color: var(--c-text);
  margin-bottom: 0.5rem;
  max-width: 32em;
}

.footer-trust {
  font-size: 0.82rem;
  color: var(--c-text-muted);
  border-left: 2px solid var(--c-accent);
  padding-left: 0.8rem;
  max-width: 34em;
}

.footer-heading {
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--c-text-bright);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid rgba(141, 162, 184, 0.2);
  position: relative;
}

.footer-heading::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 28px;
  height: 2px;
  background: var(--c-accent);
}

.footer-links-list {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.footer-links-list a {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.88rem;
  color: var(--c-text);
  transition: color var(--transition), transform var(--transition);
}

.footer-links-list a::before {
  content: '·';
  color: var(--c-accent);
  font-family: var(--font-mono);
  font-weight: 700;
}

.footer-links-list a:hover {
  color: var(--c-accent);
  transform: translateX(3px);
}

.footer-contact-line {
  font-size: 0.85rem;
  color: var(--c-text);
  margin-bottom: 0.5rem;
  line-height: 1.6;
  word-break: break-all;
}

.footer-contact-note {
  font-size: 0.75rem;
  color: var(--c-text-muted);
  border-top: 1px dashed rgba(141, 162, 184, 0.2);
  margin-top: 0.75rem;
  padding-top: 0.75rem;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding-top: 1.2rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--c-text-muted);
}

.footer-copyright {
  letter-spacing: 0.03em;
}

.footer-icp {
  letter-spacing: 0.06em;
}

/* 返回顶部 */
.back-top-btn {
  position: fixed;
  right: 1.5rem;
  bottom: 1.5rem;
  z-index: 900;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: rgba(10, 27, 42, 0.9);
  border: 1px solid var(--c-accent);
  color: var(--c-accent);
  font-size: 1.2rem;
  clip-path: polygon(8px 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%, 0 8px);
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition: opacity var(--transition), transform var(--transition), visibility 0s var(--transition);
}

.back-top-btn:focus-visible {
  outline: none;
}

.back-top-btn:focus-visible::after {
  content: '';
  position: absolute;
  inset: 2px;
  border: 2px solid var(--c-accent-alt);
  pointer-events: none;
}

.back-top-btn.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
  transition: opacity var(--transition), transform var(--transition), visibility 0s 0s;
}

.back-top-btn:hover {
  background: var(--c-accent);
  color: var(--c-bg-primary);
}

/* ---------- 7. 通用区块与组件 ---------- */
.section {
  padding: 4.5rem 0;
}

.section-heading {
  position: relative;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid rgba(141, 162, 184, 0.2);
}

.section-heading::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 56px;
  height: 2px;
  background: var(--c-accent);
}

.section-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-accent-alt);
  margin-bottom: 0.5rem;
}

.section-title {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 800;
  letter-spacing: 0.02em;
  margin: 0;
}

.vertical-note {
  display: inline-block;
  writing-mode: vertical-rl;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--c-text-muted);
  position: absolute;
  top: 0;
  right: 0;
  height: 100%;
}

.page-title {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 900;
  letter-spacing: 0.02em;
  line-height: 1.2;
  margin-bottom: 1rem;
}

.page-intro {
  font-size: 1rem;
  color: var(--c-text-muted);
  max-width: 46em;
  line-height: 1.8;
}

/* 网格 */
.grid,
.grid-2,
.grid-3,
.grid-4 {
  display: grid;
  gap: 1.5rem;
}

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

/* 切角卡片 */
.chamfer-card {
  position: relative;
  background: var(--c-bg-secondary);
  padding: 1.5rem 1.25rem;
  border: 1px solid rgba(141, 162, 184, 0.12);
  clip-path: polygon(var(--chamfer) 0, 100% 0, 100% calc(100% - var(--chamfer)), calc(100% - var(--chamfer)) 100%, 0 100%, 0 var(--chamfer));
  transition: transform var(--transition), background-color var(--transition), border-color var(--transition);
}

.chamfer-card:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 107, 44, 0.4);
}

/* 分区背景色 */
.bg-wine {
  background: var(--c-bg-wine);
}

.bg-indigo {
  background: var(--c-bg-indigo);
}

.bg-secondary {
  background: var(--c-bg-secondary);
}

/* 标签 */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.2rem 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: var(--c-accent-alt);
  border: 1px solid rgba(0, 229, 160, 0.3);
  background: rgba(0, 229, 160, 0.06);
  border-radius: 2px;
}

/* 坐标标签 */
.coord-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--c-data);
  background: rgba(255, 209, 102, 0.08);
  padding: 2px 8px;
  border-left: 2px solid var(--c-data);
  white-space: nowrap;
}

/* 斜线分隔 */
.divider-line {
  display: block;
  height: 1px;
  width: 100%;
  background: transparent;
  position: relative;
  overflow: hidden;
  margin: 2rem 0;
}

.divider-line::before {
  content: '';
  position: absolute;
  top: 0;
  left: -10%;
  width: 60%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--c-accent), var(--c-accent-alt));
  transform: rotate(-2deg);
  transform-origin: left;
}

/* 地图图例 */
.map-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  padding: 0.8rem 1rem;
  background: rgba(10, 27, 42, 0.5);
  border: 1px dashed rgba(141, 162, 184, 0.25);
  margin: 1rem 0;
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--c-text-muted);
}

.legend-item .status-dot {
  animation: none;
  width: 8px;
  height: 8px;
  border-radius: 0;
  clip-path: polygon(2px 0, 100% 0, 100% calc(100% - 2px), calc(100% - 2px) 100%, 0 100%, 0 2px);
}

.legend-item:nth-child(1) .status-dot { background: var(--c-accent); }
.legend-item:nth-child(2) .status-dot { background: var(--c-accent-alt); }
.legend-item:nth-child(3) .status-dot { background: var(--c-data); }
.legend-item:nth-child(4) .status-dot { background: var(--c-bg-wine); }

/* 数据数字 */
.data-num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--c-data);
  letter-spacing: -0.02em;
  line-height: 1.2;
}

/* 数据流装饰线 */
.data-stream {
  display: block;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--c-accent) 30%, var(--c-accent-alt) 60%, transparent);
  background-size: 200% 100%;
  animation: stream-flow 4s linear infinite;
  opacity: 0.5;
  border-radius: 2px;
}

@keyframes stream-flow {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ---------- 8. 滚动显现 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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

[data-reveal-delay="1"] { transition-delay: 0.1s; }
[data-reveal-delay="2"] { transition-delay: 0.2s; }
[data-reveal-delay="3"] { transition-delay: 0.3s; }
[data-reveal-delay="4"] { transition-delay: 0.4s; }
[data-reveal-delay="5"] { transition-delay: 0.5s; }

/* ---------- 9. 响应式 ---------- */
@media (max-width: 1024px) {
  .header-status {
    display: none;
  }

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

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    padding: 0 1.25rem;
    margin-left: 0;
    background: rgba(10, 27, 42, 0.98);
    border-bottom: 2px solid var(--c-accent);
    box-shadow: 0 16px 32px rgba(0, 0, 0, 0.4);
    clip-path: polygon(0 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%);
    visibility: hidden;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease, visibility 0s 0.35s;
    z-index: 999;
  }

  .site-nav[data-open] {
    visibility: visible;
    max-height: 90vh;
    overflow-y: auto;
    transition: max-height 0.35s ease, visibility 0s 0s;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.5rem 0 1.25rem;
  }

  .nav-item {
    border-bottom: 1px solid rgba(141, 162, 184, 0.12);
  }

  .nav-item:last-child {
    border-bottom: none;
  }

  .nav-link {
    display: block;
    padding: 0.85rem 0.5rem;
    font-size: 1rem;
  }

  .nav-link::after {
    display: none;
  }

  .nav-link[aria-current="page"] {
    color: var(--c-accent);
    padding-left: 1rem;
    border-left: 3px solid var(--c-accent);
  }

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

  .footer-top {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .section {
    padding: 3rem 0;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .footer-inner {
    padding-block: 2rem 1rem;
  }

  .footer-top {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.35rem;
  }

  .brand-logo-name strong {
    font-size: 1.05rem;
  }

  .brand-logo-mark {
    width: 36px;
    height: 36px;
    font-size: 0.85rem;
  }

  .pc-entry-btn {
    padding: 0.45rem 0.8rem;
    font-size: 0.75rem;
  }

  .vertical-note {
    display: none;
  }

  .back-top-btn {
    right: 1rem;
    bottom: 1rem;
    width: 40px;
    height: 40px;
  }
}

@media (max-width: 480px) {
  .header-inner {
    min-height: 60px;
  }

  .brand-logo {
    gap: 0.45rem;
  }

  .brand-logo-name small {
    display: none;
  }

  .brand-logo-mark {
    width: 34px;
    height: 34px;
    font-size: 0.8rem;
  }

  .pc-entry-btn {
    padding: 0.4rem 0.7rem;
    font-size: 0.72rem;
  }

  .nav-toggle {
    width: 40px;
    height: 40px;
    gap: 4px;
  }

  .nav-toggle-line {
    width: 16px;
  }
}

/* ---------- 10. 沉浸模式 ---------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

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

  .status-dot {
    animation: none;
  }

  .data-stream {
    background: var(--c-accent);
    opacity: 0.3;
    animation: none;
  }

  .btn:hover,
  .chamfer-card:hover {
    transform: none;
  }
}