:root {
  --color-primary: #0A192F;
  --color-primary-deep: #060F1E;
  --color-secondary: #112240;
  --color-tertiary: #1D3E5E;
  --color-accent: #FF6B35;
  --color-accent-light: #FF9A7A;
  --color-silver: #C0C0C0;
  --color-light: #FFFFFF;
  --color-gray: #F5F5F5;
  --color-text: #E8EDF2;
  --color-text-muted: #A8B3C0;
  --color-headline: #FFFFFF;
  --color-body-bg: var(--color-primary);
  --color-card-bg: var(--color-secondary);
  --color-border: var(--color-tertiary);
  --font-headline: 'Montserrat ExtraBold', 'Impact', 'Noto Sans SC', 'Helvetica Neue', sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', 'Helvetica Neue', Arial, sans-serif;
  --font-numeric: 'JetBrains Mono', 'SF Mono', 'Menlo', monospace;
  --font-scale-ratio: 1.25;
  --text-sm: 0.8rem;
  --text-base: 1rem;
  --text-md: 1.25rem;
  --text-lg: 1.563rem;
  --text-xl: 1.953rem;
  --text-2xl: 2.441rem;
  --text-3xl: 3.052rem;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4rem;
  --space-9: 6rem;
  --container-max: 1280px;
  --container-pad: clamp(1rem, 4vw, 2rem);
  --header-bg: rgba(10, 25, 47, 0.92);
  --header-border: rgba(192, 192, 192, 0.18);
  --shadow-card: 0 12px 40px rgba(0, 0, 0, 0.35);
  --shadow-cta: 0 8px 30px rgba(255, 107, 53, 0.28);
  --radius-md: 6px;
  --radius-lg: 12px;
  --radius-xl: 20px;
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --transition-speed: 0.28s;
  --page-top-offset: 118px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  background-color: var(--color-body-bg);
  color: var(--color-text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

body.is-nav-open {
  overflow: hidden;
}

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

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition-speed) var(--ease-out);
}

a:hover {
  color: var(--color-accent-light);
}

ul,
ol {
  list-style: none;
}

button {
  font-family: var(--font-body);
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 4px;
  border-radius: 4px;
}

.skip-link {
  position: fixed;
  top: -100px;
  left: 1rem;
  z-index: 10000;
  background: var(--color-accent);
  color: var(--color-primary);
  font-weight: 800;
  padding: 0.6rem 1.2rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-cta);
  transition: top 0.3s var(--ease-out);
}

.skip-link:focus {
  top: 0.75rem;
  color: var(--color-primary);
}

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding-left: var(--container-pad);
  padding-right: var(--container-pad);
}

/* ============ 头部 ============ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--header-bg);
  backdrop-filter: blur(18px) saturate(140%);
  -webkit-backdrop-filter: blur(18px) saturate(140%);
  border-bottom: 1px solid var(--header-border);
  padding-top: 0.5rem;
  transition: background var(--transition-speed) var(--ease-out);
}

.header-inner {
  padding-top: 0.25rem;
  padding-bottom: 0.25rem;
}

.topbar-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: 0.4rem 0 0.7rem;
  border-bottom: 1px dashed var(--color-border);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  letter-spacing: 0.03em;
}

.meta-trust {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  white-space: nowrap;
}

.trust-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 0 4px rgba(255, 107, 53, 0.18);
  animation: pulse-dot 2.4s infinite;
}

.brand-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-5);
  padding: 1rem 0 0.8rem;
}

.brand-lockup,
.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-4);
  flex-shrink: 0;
  text-decoration: none;
}

.brand-mark {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 2px solid var(--color-silver);
  border-radius: var(--radius-md);
  position: relative;
  overflow: hidden;
  background: linear-gradient(145deg, rgba(255, 255, 255, 0.06), transparent);
}

.brand-mark::before {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  background: repeating-linear-gradient(135deg, transparent 0, transparent 6px, rgba(255, 107, 53, 0.18) 6px, rgba(255, 107, 53, 0.18) 7px);
  opacity: 0.6;
}

.brand-mark-dot {
  width: 10px;
  height: 10px;
  background: var(--color-accent);
  border-radius: 50%;
  position: relative;
  z-index: 1;
  box-shadow: 0 0 12px rgba(255, 107, 53, 0.9);
}

.brand-mark-line {
  width: 22px;
  height: 2px;
  background: var(--color-silver);
  margin-top: 5px;
  position: relative;
  z-index: 1;
}

.brand-mark-small {
  width: 34px;
  height: 34px;
}

.brand-mark-small .brand-mark-line {
  width: 16px;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-name {
  font-family: var(--font-headline);
  font-weight: 900;
  font-size: 1.4rem;
  letter-spacing: -0.02em;
  color: var(--color-light);
  text-transform: uppercase;
}

.brand-sub {
  font-family: var(--font-numeric);
  font-size: 0.72rem;
  letter-spacing: 0.28em;
  color: var(--color-silver);
  margin-top: 0.15rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: var(--text-sm);
  padding: 0.7rem 1.2rem;
  border-radius: var(--radius-md);
  letter-spacing: 0.01em;
  transition: background var(--transition-speed) var(--ease-out), color var(--transition-speed) var(--ease-out), box-shadow var(--transition-speed) var(--ease-out), transform var(--transition-speed) var(--ease-out);
  white-space: nowrap;
}

.btn-accent {
  background: var(--color-accent);
  color: var(--color-primary);
  box-shadow: 0 4px 16px rgba(255, 107, 53, 0.24);
}

.btn-accent:hover {
  background: var(--color-accent-light);
  color: var(--color-primary);
  box-shadow: var(--shadow-cta);
  transform: translateY(-2px);
}

.btn-icon {
  font-size: 1.1rem;
  line-height: 1;
  transition: transform var(--transition-speed) var(--ease-out);
}

.btn-accent:hover .btn-icon {
  transform: translate(2px, -2px);
}

.btn-download-header {
  padding: 0.6rem 1rem;
  font-size: 0.9rem;
}

/* 导航 */

.nav-bar {
  border-top: 1px solid transparent;
}

.nav-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  padding: 0.2rem 0 0.6rem;
}

.nav-link {
  position: relative;
  display: block;
  padding: 0.55rem 0.9rem;
  font-family: var(--font-headline);
  font-weight: 800;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  color: var(--color-text);
  border-radius: var(--radius-md);
  transition: color var(--transition-speed) var(--ease-out), background var(--transition-speed) var(--ease-out);
}

.nav-link::after {
  content: '';
  position: absolute;
  left: 0.9rem;
  right: 0.9rem;
  bottom: 0.25rem;
  height: 3px;
  background: var(--color-accent);
  border-radius: 4px;
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--transition-speed) var(--ease-out);
}

.nav-link:hover {
  color: var(--color-accent-light);
  background: rgba(255, 107, 53, 0.06);
}

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

.nav-link[aria-current="page"],
.nav-link[data-current="true"] {
  color: var(--color-accent);
  font-weight: 900;
}

/* 移动导航按钮 */

.nav-toggle {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.3rem;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-secondary);
  color: var(--color-text);
  font-size: var(--text-sm);
  transition: border-color var(--transition-speed) var(--ease-out), background var(--transition-speed) var(--ease-out);
}

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

.nav-toggle-bars {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 18px;
}

.nav-toggle-bars .bar {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-light);
  border-radius: 4px;
  transition: transform var(--transition-speed) var(--ease-out), opacity var(--transition-speed) var(--ease-out);
}

.nav-toggle-text {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

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

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

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

/* 滚动进度条 */

.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  background: transparent;
  pointer-events: none;
}

.progress-bar-inner {
  display: block;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-light), var(--color-accent));
  transform: scaleX(0);
  transform-origin: left center;
}

/* ============ 页脚 ============ */

.site-footer {
  margin-top: auto;
  background: var(--color-primary-deep);
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-7);
  padding-bottom: var(--space-5);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.footer-container {
  display: grid;
  grid-template-columns: 1fr 1.5fr 1.2fr;
  gap: var(--space-6);
  align-items: start;
}

.footer-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer-brand {
  margin-bottom: var(--space-2);
}

.footer-brand .brand-name {
  font-size: 1.25rem;
}

.footer-trust {
  max-width: 32ch;
  line-height: 1.6;
  color: var(--color-text);
}

.footer-contact a {
  color: var(--color-text);
  font-weight: 500;
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-speed) var(--ease-out), color var(--transition-speed) var(--ease-out);
}

.footer-contact a:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.contact-sep {
  margin: 0 0.4rem;
  color: var(--color-tertiary);
}

.footer-address {
  color: var(--color-text-muted);
}

.footer-links {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-5);
}

.footer-links-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer-label {
  font-family: var(--font-headline);
  font-weight: 800;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-silver);
}

.footer-nav-list li + li {
  margin-top: 0.4rem;
}

.footer-nav-list a {
  display: inline-block;
  color: var(--color-text);
  font-weight: 500;
  padding: 0.15rem 0;
  border-bottom: 1px solid transparent;
  transition: color var(--transition-speed) var(--ease-out), border-color var(--transition-speed) var(--ease-out);
}

.footer-nav-list a:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.footer-cert {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  align-items: flex-start;
  border-left: 1px solid var(--color-border);
  padding-left: var(--space-5);
}

.footer-cert-line {
  line-height: 1.5;
}

/* ============ 通用布局 ============ */

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: clamp(1rem, 3vw, 2rem);
}

.col-note {
  grid-column: span 3;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.col-main {
  grid-column: span 8;
}

.col-aside {
  grid-column: span 4;
}

@media (min-width: 1200px) {
  .col-note {
    grid-column: span 2;
    margin-top: 0.5rem;
  }

  .col-main {
    grid-column: span 8;
  }

  .col-aside {
    grid-column: span 3;
  }
}

@media (max-width: 900px) {
  .col-note,
  .col-main,
  .col-aside {
    grid-column: span 12;
  }
}

/* 页面头 */

.page-head {
  position: relative;
  padding: var(--space-6) 0 var(--space-6);
  margin-bottom: var(--space-5);
  border-bottom: 1px solid var(--color-border);
}

.page-head::before {
  content: '';
  position: absolute;
  width: 120px;
  height: 120px;
  right: -30px;
  top: -20px;
  background: linear-gradient(135deg, transparent 45%, rgba(255, 107, 53, 0.25) 45%, rgba(255, 107, 53, 0.25) 55%, transparent 55%);
  pointer-events: none;
}

.page-kicker {
  font-family: var(--font-numeric);
  font-size: var(--text-sm);
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-2);
  display: block;
}

.page-title {
  font-family: var(--font-headline);
  font-weight: 900;
  font-size: clamp(2rem, 5vw, 3.5rem);
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--color-headline);
  max-width: 18ch;
  text-transform: uppercase;
}

.page-intro {
  max-width: 65ch;
  font-size: var(--text-md);
  line-height: 1.7;
  color: var(--color-text-muted);
  margin-top: var(--space-3);
}

/* 章节与内容 */

.section-head {
  display: flex;
  align-items: baseline;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
  border-bottom: 2px solid var(--color-border);
  padding-bottom: var(--space-2);
}

.section-label {
  font-family: var(--font-numeric);
  font-size: var(--text-sm);
  color: var(--color-accent);
  font-weight: 700;
  letter-spacing: 0.1em;
}

.section-title {
  font-family: var(--font-headline);
  font-weight: 900;
  font-size: var(--text-lg);
  color: var(--color-light);
  letter-spacing: -0.01em;
}

.divider-slash {
  display: block;
  height: 8px;
  background: repeating-linear-gradient(135deg, var(--color-accent) 0, var(--color-accent) 8px, transparent 8px, transparent 16px);
  border: none;
  opacity: 0.5;
  margin: var(--space-4) 0;
}

.body-text {
  font-size: var(--text-base);
  line-height: 1.8;
  color: var(--color-text);
  max-width: 65ch;
}

.body-text p + p {
  margin-top: 1.2em;
}

.body-text strong {
  color: var(--color-light);
  font-weight: 700;
}

.mono-num {
  font-family: var(--font-numeric);
  letter-spacing: 0.05em;
  font-variant-numeric: tabular-nums;
  color: var(--color-accent);
}

/* 通用卡片 / 数据面板 */

.data-panel,
.status-panel {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  box-shadow: var(--shadow-card);
}

.panel-row {
  display: flex;
  justify-content: space-between;
  gap: var(--space-3);
  padding: var(--space-2) 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.panel-row:last-child {
  border-bottom: none;
}

.panel-label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.panel-value {
  font-family: var(--font-numeric);
  font-weight: 700;
  color: var(--color-light);
}

/* 标签组 */

.data-chips {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--color-secondary);
  border: 1px solid var(--color-border);
  border-radius: 100px;
  padding: 0.3rem 0.8rem;
  font-family: var(--font-numeric);
  font-size: 0.8rem;
  color: var(--color-silver);
  letter-spacing: 0.03em;
}

.chip[data-chip-accent] {
  background: rgba(255, 107, 53, 0.1);
  border-color: var(--color-accent);
  color: var(--color-accent);
  font-weight: 700;
}

/* 图片容器 */

.image-frame {
  position: relative;
  overflow: hidden;
  background: var(--color-secondary);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
}

.image-frame::before {
  content: '';
  display: block;
  padding-bottom: 56.25%;
}

.image-frame[data-ratio="landscape"]::before {
  padding-bottom: 56.25%;
}

.image-frame[data-ratio="portrait"]::before {
  padding-bottom: 100%;
}

.image-frame[data-ratio="wide"]::before {
  padding-bottom: 40%;
}

.image-frame::after {
  content: 'IMAGE';
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  font-family: var(--font-numeric);
  font-size: var(--text-sm);
  letter-spacing: 0.2em;
  color: var(--color-text-muted);
  z-index: 1;
}

.image-frame > img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 2;
}

/* 返回顶部 */

.back-to-top {
  position: fixed;
  right: 1.25rem;
  bottom: 1.25rem;
  z-index: 800;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--color-accent);
  color: var(--color-primary);
  font-size: 1.4rem;
  display: grid;
  place-items: center;
  box-shadow: 0 8px 24px rgba(255, 107, 53, 0.3);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity var(--transition-speed) var(--ease-out), transform var(--transition-speed) var(--ease-out), visibility var(--transition-speed) var(--ease-out);
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--color-accent-light);
  transform: translateY(-2px);
}

.back-to-top svg {
  pointer-events: none;
}

/* 显现动画 */

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out);
}

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

@media (max-width: 900px) {
  :root {
    --page-top-offset: 70px;
  }

  .topbar-meta {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.2rem;
    padding-bottom: 0.4rem;
  }

  .meta-slogan {
    display: none;
  }

  .brand-bar {
    padding: 0.6rem 0;
  }

  .brand-name {
    font-size: 1.2rem;
  }

  .brand-sub {
    font-size: 0.6rem;
  }

  .btn-download-header {
    margin-left: auto;
    padding: 0.5rem 0.8rem;
  }

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

  .nav-bar {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows var(--transition-speed) var(--ease-out);
  }

  .nav-bar::before {
    content: '';
    display: block;
  }

  .nav-list {
    overflow: hidden;
  }

  .nav-bar[data-open] {
    grid-template-rows: 1fr;
    border-top: 1px solid var(--color-border);
    margin-top: 0.5rem;
  }

  .nav-list {
    flex-direction: column;
    gap: 0;
    padding: 0.5rem 0 1rem;
  }

  .nav-link {
    padding: 0.7rem 0.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.04);
  }

  .nav-link::after {
    left: 0.5rem;
    right: 0.5rem;
    bottom: 0.2rem;
    height: 2px;
  }

  .footer-container {
    grid-template-columns: 1fr;
    gap: var(--space-5);
  }

  .footer-cert {
    border-left: none;
    padding-left: 0;
    border-top: 1px solid var(--color-border);
    padding-top: var(--space-4);
  }
}

@media (max-width: 600px) {
  .brand-mark {
    width: 36px;
    height: 36px;
  }

  .brand-mark-line {
    width: 16px;
  }

  .brand-name {
    font-size: 1.1rem;
  }

  .brand-sub {
    font-size: 0.55rem;
    letter-spacing: 0.2em;
  }

  .btn-download-header .btn-icon {
    display: none;
  }

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

@media (min-width: 1200px) {
  .nav-list {
    gap: 0.2rem;
  }

  .nav-link {
    font-size: 1rem;
  }
}

/* 动画 */

@keyframes pulse-dot {
  0%, 100% {
    transform: scale(1);
    box-shadow: 0 0 0 0 rgba(255, 107, 53, 0.4);
  }
  50% {
    transform: scale(1.15);
    box-shadow: 0 0 0 6px rgba(255, 107, 53, 0);
  }
}

@keyframes slide-up {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* 尊重减少动态偏好 */

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001s !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001s !important;
    scroll-behavior: auto !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }

  .back-to-top {
    transition: none;
  }
}