/* ===== 全域重置 ===== */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; padding: 0; }

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

body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.7;
  color: var(--text-high);
  background-color: var(--bg-void);
  background-image:
    linear-gradient(rgba(0, 229, 255, 0.022) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 229, 255, 0.022) 1px, transparent 1px);
  background-size: 40px 40px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

ul, ol { list-style: none; }
a { color: inherit; text-decoration: none; }
button { background: none; border: none; cursor: pointer; }

hr {
  border: 0;
  height: 1px;
  background: var(--line-strong);
  margin: var(--space-3) 0;
}

/* ===== CSS 变量 ===== */
:root {
  --bg-void: #060B14;
  --bg-surface: #0F172A;
  --bg-elevated: #1E293B;
  --line-strong: #334155;
  --accent-cyan: #00E5FF;
  --accent-lime: #BFFF00;
  --accent-violet: #A78BFA;
  --text-high: #F8FAFC;
  --text-mid: #CBD5E1;
  --text-low: #64748B;
  --positive: #34D399;
  --warning: #FBBF24;
  --danger: #F87171;

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

  --fs-hero: 3.5rem;
  --fs-h1: 2.5rem;
  --fs-h2: 1.75rem;
  --fs-h3: 1.25rem;
  --fs-body: 1rem;

  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 40px;
  --space-5: 64px;
  --space-6: 96px;

  --shadow-hard: 8px 8px 0 rgba(0, 0, 0, 0.4);
  --shadow-cyan: 8px 8px 0 rgba(0, 229, 255, 0.14);
}

/* ===== 排版基线 ===== */
h1, h2, h3, h4 {
  line-height: 1.2;
  font-weight: 800;
  color: var(--text-high);
  text-wrap: balance;
}

p { color: var(--text-mid); }
strong { color: var(--text-high); font-weight: 700; }

::selection {
  background: var(--accent-cyan);
  color: var(--bg-void);
}

.content {
  font-size: var(--fs-body);
  line-height: 1.75;
  color: var(--text-mid);
}

.content a {
  color: var(--accent-cyan);
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 1px;
}

.content a:hover {
  color: var(--accent-lime);
}

.content blockquote {
  margin: var(--space-3) 0;
  padding: var(--space-2) var(--space-3);
  border-left: 4px solid var(--accent-cyan);
  background: var(--bg-surface);
  color: var(--text-mid);
}

.content ul,
.content ol {
  padding-left: 1.4em;
  color: var(--text-mid);
}

.content ul { list-style: square; }
.content ol { list-style: decimal; }
.content li { margin: 4px 0; }
.content img { margin: var(--space-3) 0; }

/* ===== 焦点与动效安全 ===== */
:focus-visible {
  outline: 3px solid var(--accent-cyan);
  outline-offset: 2px;
  border-radius: 0;
}

@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: 0s !important;
  }
}

/* ===== 容器与网格 ===== */
.container {
  width: 100%;
  max-width: 1440px;
  margin-inline: auto;
  padding-inline: 28px;
}

.container--narrow {
  max-width: 900px;
}

.main-content {
  flex: 1 0 auto;
  width: 100%;
  padding-bottom: var(--space-5);
}

#main-content {
  scroll-margin-top: 88px;
}

.layout-feed {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 0.55fr);
  gap: 32px;
  align-items: start;
}

.panel-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
}

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

.section-block {
  padding: var(--space-4) 0;
}

/* ===== 滚动进度线 ===== */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-lime));
  box-shadow: 0 0 10px rgba(0, 229, 255, 0.35);
  z-index: 200;
  pointer-events: none;
}

/* ===== 跳转链接 ===== */
.skip-link {
  position: fixed;
  top: -64px;
  left: 16px;
  z-index: 300;
  padding: 12px 20px;
  background: var(--accent-cyan);
  color: var(--bg-void);
  font-weight: 900;
  font-size: 14px;
  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.5);
  transition: top 0.25s ease;
}

.skip-link:focus-visible {
  top: 16px;
}

/* ===== 命令栏头部 ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(6, 11, 20, 0.92);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line-strong);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.45);
}

.site-header::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 140px;
  height: 2px;
  background: linear-gradient(90deg, var(--accent-cyan), transparent);
  pointer-events: none;
}

.header-inner {
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  gap: 24px;
  min-height: 72px;
  position: relative;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 20px;
  min-width: 0;
  padding: 12px 0;
}

/* 品牌 */
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.brand__mark {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  background: var(--accent-cyan);
  color: var(--bg-void);
  font-family: var(--font-mono);
  font-size: 17px;
  font-weight: 800;
  letter-spacing: 0.02em;
  clip-path: polygon(0 0, 100% 0, 100% 70%, 72% 100%, 0 100%);
}

.brand__text {
  display: flex;
  flex-direction: column;
  justify-content: center;
  line-height: 1.25;
}

.brand__name {
  font-size: 18px;
  font-weight: 900;
  letter-spacing: 0.04em;
  color: var(--text-high);
  white-space: nowrap;
}

.brand__tag {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-low);
  letter-spacing: 0.08em;
  white-space: nowrap;
}

/* 状态指示 */
.sys-status {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  border: 1px solid var(--line-strong);
  background: rgba(15, 23, 42, 0.55);
}

.sys-status__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--positive);
  box-shadow: 0 0 8px rgba(52, 211, 153, 0.55);
  flex-shrink: 0;
}

.sys-status__text {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-mid);
  white-space: nowrap;
}

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

.nav-list {
  display: flex;
  align-items: stretch;
  height: 100%;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0 12px;
  font-size: 14px;
  font-weight: 700;
  color: var(--text-mid);
  position: relative;
  transition: color 0.2s ease;
  white-space: nowrap;
}

.nav-link::after {
  content: '';
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 0;
  height: 3px;
  background: var(--accent-cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.25s ease;
}

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

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

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

.nav-link__index {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-low);
  transition: color 0.2s ease;
}

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

/* 导航开关按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 2px solid var(--line-strong);
  background: transparent;
  color: var(--text-high);
  transition: border-color 0.2s ease, color 0.2s ease;
}

.nav-toggle:hover,
.nav-toggle.is-open {
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
}

.nav-toggle__bars {
  display: flex;
  flex-direction: column;
  width: 18px;
}

.nav-toggle__bar {
  height: 2px;
  background: currentColor;
  margin: 2px 0;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.nav-toggle.is-open .nav-toggle__bar:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.nav-toggle.is-open .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle.is-open .nav-toggle__bar:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

.nav-toggle__text {
  font-size: 13px;
  font-weight: 700;
}

/* ===== 页脚 ===== */
.site-footer {
  position: relative;
  margin-top: var(--space-5);
  background: var(--bg-surface);
  border-top: 2px solid var(--line-strong);
}

.site-footer::before {
  content: '';
  position: absolute;
  top: -2px;
  left: 0;
  width: 200px;
  height: 2px;
  background: var(--accent-cyan);
  z-index: 1;
}

.site-footer::after {
  content: '';
  position: absolute;
  top: -2px;
  left: 200px;
  width: 28px;
  height: 2px;
  background: var(--accent-lime);
  z-index: 1;
}

.footer-top {
  padding: var(--space-5) 0 var(--space-4);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.3fr 0.8fr 0.9fr 1.1fr;
  gap: 40px;
}

.footer-col--brand {
  max-width: 420px;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: var(--space-2);
}

.footer-brand__mark {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: var(--accent-cyan);
  color: var(--bg-void);
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 800;
  clip-path: polygon(0 0, 100% 0, 100% 65%, 70% 100%, 0 100%);
}

.footer-brand__name {
  font-size: 16px;
  font-weight: 800;
  letter-spacing: 0.03em;
  color: var(--text-high);
}

.footer-blurb {
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-mid);
  margin-bottom: var(--space-2);
}

.footer-trust {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-low);
}

.footer-trust__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--positive);
  box-shadow: 0 0 8px rgba(52, 211, 153, 0.55);
  flex-shrink: 0;
}

.footer-h {
  margin-bottom: var(--space-2);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--text-low);
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 8px;
}

.footer-h::before {
  content: '';
  width: 16px;
  height: 2px;
  background: var(--accent-cyan);
  flex-shrink: 0;
}

.footer-list__item {
  margin-bottom: 10px;
}

.footer-list__item a {
  font-size: 14px;
  color: var(--text-mid);
  transition: color 0.2s ease;
}

.footer-list__item a:hover {
  color: var(--accent-cyan);
}

.footer-contact-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.footer-contact__label {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-low);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.footer-contact__value {
  font-size: 14px;
  color: var(--text-mid);
  word-break: break-all;
}

.footer-bottom {
  border-top: 1px solid var(--line-strong);
  padding: var(--space-2) 0;
}

.footer-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.footer-copy,
.footer-icp {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-low);
}

/* ===== 通用按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  color: var(--text-high);
  background: transparent;
  border: 2px solid var(--line-strong);
  cursor: pointer;
  text-decoration: none;
  transition: background 0.2s ease, border-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease, transform 0.1s ease;
}

.btn:hover {
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
}

.btn:active {
  background: var(--accent-lime);
  border-color: var(--accent-lime);
  color: var(--bg-void);
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 rgba(0, 0, 0, 0.3);
}

.btn--primary {
  background: var(--accent-lime);
  border-color: var(--accent-lime);
  color: var(--bg-void);
  box-shadow: 4px 4px 0 rgba(0, 0, 0, 0.35);
}

.btn--primary:hover {
  background: #d4ff33;
  border-color: #d4ff33;
  color: var(--bg-void);
}

.btn--primary:active {
  background: #e6ff66;
  border-color: #e6ff66;
}

.btn--ghost {
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
}

.btn--ghost:hover {
  background: rgba(0, 229, 255, 0.12);
}

.btn--small {
  padding: 8px 14px;
  font-size: 13px;
}

/* ===== 面包屑 ===== */
.crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  padding: 12px 0;
  margin-bottom: var(--space-3);
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-low);
  border-bottom: 1px solid var(--line-strong);
}

.crumb li {
  display: flex;
  align-items: center;
}

.crumb li + li::before {
  content: '/';
  margin: 0 8px;
  color: var(--text-low);
}

.crumb a {
  color: var(--text-mid);
  transition: color 0.2s ease;
}

.crumb a:hover {
  color: var(--accent-cyan);
}

.crumb [aria-current="page"] {
  color: var(--text-low);
}

/* ===== 章节头 ===== */
.sec-head {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding-bottom: 12px;
  margin-bottom: var(--space-3);
  border-bottom: 2px solid var(--line-strong);
  position: relative;
}

.sec-head::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 48px;
  height: 2px;
  background: var(--accent-cyan);
}

.sec-index {
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  color: var(--accent-cyan);
  letter-spacing: 0.08em;
}

.sec-title {
  font-size: var(--fs-h2);
  margin: 0;
}

.sec-desc {
  max-width: 640px;
  margin: 0 0 var(--space-3);
  font-size: 15px;
  color: var(--text-mid);
}

/* ===== 页面横幅 ===== */
.page-hero {
  position: relative;
  padding: var(--space-4) 0 var(--space-3);
  margin-bottom: var(--space-3);
  border-bottom: 1px solid var(--line-strong);
}

.page-hero::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 96px;
  height: 2px;
  background: var(--accent-cyan);
}

.page-hero__title {
  font-size: var(--fs-h1);
  margin: 0 0 var(--space-1);
}

.page-hero__desc {
  max-width: 640px;
  margin: 0;
  font-size: 16px;
  color: var(--text-mid);
}

/* ===== 首屏章节预览 ===== */
.ch-preview {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-bottom: var(--space-4);
}

.ch-preview__item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  border: 2px solid var(--line-strong);
  background: var(--bg-surface);
  box-shadow: var(--shadow-hard);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.ch-preview__item:hover {
  border-color: var(--accent-cyan);
  box-shadow: var(--shadow-cyan);
}

.ch-preview__index {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent-cyan);
}

.ch-preview__label {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-mid);
}

/* ===== 面板 ===== */
.panel {
  padding: 24px;
  background: var(--bg-surface);
  border: 2px solid var(--line-strong);
  box-shadow: var(--shadow-hard);
  transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.panel:hover {
  border-color: var(--accent-cyan);
  box-shadow: var(--shadow-cyan);
}

.panel--lime {
  border-color: rgba(191, 255, 0, 0.5);
}

.panel--lime:hover {
  border-color: var(--accent-lime);
}

.panel--violet {
  border-color: rgba(167, 139, 250, 0.5);
}

.panel--violet:hover {
  border-color: var(--accent-violet);
}

/* ===== 数据统计块 ===== */
.stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: var(--space-2);
  background: var(--bg-surface);
  border-left: 3px solid var(--accent-cyan);
}

.stat__value {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.1;
  color: var(--accent-cyan);
}

.stat__label {
  font-size: 13px;
  color: var(--text-low);
}

/* ===== 展览说明牌 ===== */
.fig-label {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 4px 14px 4px 4px;
  border: 1px solid var(--line-strong);
  background: var(--bg-elevated);
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-mid);
  letter-spacing: 0.04em;
}

.fig-label__no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  background: var(--accent-cyan);
  color: var(--bg-void);
  font-weight: 800;
  font-size: 12px;
}

/* ===== 图片占位框 ===== */
.img-frame {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: var(--bg-elevated);
  border: 2px solid var(--line-strong);
  overflow: hidden;
}

.img-frame::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(0, 229, 255, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 229, 255, 0.05) 1px, transparent 1px);
  background-size: 24px 24px;
}

.img-frame::after {
  content: 'IMG';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 6px 14px;
  border: 1px solid var(--line-strong);
  background: rgba(6, 11, 20, 0.75);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.3em;
  color: var(--text-low);
}

.img-frame img {
  position: relative;
  z-index: 2;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.img-frame--portrait {
  aspect-ratio: 3 / 4;
}

.img-frame--square {
  aspect-ratio: 1 / 1;
}

.img-frame--banner {
  aspect-ratio: 21 / 9;
}

/* ===== 数据文本与表格 ===== */
.data-mono {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 500;
  color: var(--accent-cyan);
  font-variant-numeric: tabular-nums;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-surface);
  font-size: 14px;
}

.data-table th {
  padding: 12px 16px;
  border-bottom: 2px solid var(--line-strong);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-align: left;
  color: var(--text-low);
  text-transform: uppercase;
}

.data-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--line-strong);
  color: var(--text-mid);
}

.data-table tbody tr {
  transition: background 0.15s ease;
}

.data-table tbody tr:hover {
  background: rgba(0, 229, 255, 0.04);
}

/* ===== 状态徽章 ===== */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border: 1px solid var(--line-strong);
  background: var(--bg-surface);
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-mid);
}

.badge--ok {
  border-color: rgba(52, 211, 153, 0.4);
  color: var(--positive);
}

.badge--warn {
  border-color: rgba(251, 191, 36, 0.4);
  color: var(--warning);
}

/* ===== 响应式 ===== */
@media (max-width: 1023px) {
  .layout-feed {
    grid-template-columns: 1fr;
  }

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

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

  .nav-toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .site-nav {
    margin-left: 0;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(15, 23, 42, 0.98);
    border-top: 2px solid var(--accent-cyan);
    border-bottom: 2px solid var(--line-strong);
    max-height: 0;
    overflow: hidden;
    visibility: hidden;
    transition: max-height 0.3s ease, visibility 0s linear 0.31s;
  }

  .site-nav[data-open] {
    max-height: calc(100vh - 72px);
    overflow-y: auto;
    visibility: visible;
    transition: max-height 0.3s ease, visibility 0s;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    height: auto;
    padding: 12px 0;
  }

  .nav-link {
    height: auto;
    padding: 14px 28px;
    border-bottom: 1px solid var(--line-strong);
  }

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

  .nav-link[aria-current="page"] {
    background: rgba(0, 229, 255, 0.08);
    color: var(--accent-cyan);
  }
}

@media (max-width: 768px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }
}

@media (max-width: 640px) {
  :root {
    --fs-hero: 2.5rem;
    --fs-h1: 1.9rem;
    --fs-h2: 1.4rem;
    --fs-h3: 1.15rem;
  }

  .container {
    padding-inline: 16px;
  }

  .header-inner {
    min-height: 64px;
  }

  .brand__mark {
    width: 36px;
    height: 36px;
    font-size: 15px;
  }

  .brand__name {
    font-size: 16px;
  }

  .brand__tag {
    display: none;
  }

  .sys-status {
    display: none;
  }

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

  .section-block {
    padding: var(--space-3) 0;
  }
}