/* ============ 1. Variables ============ */
:root {
  --aob-c-primary: #0B1B3F;
  --aob-c-gold: #C9A063;
  --aob-c-orange: #FF6B35;
  --aob-c-rock: #4A5568;
  --aob-c-moss: #6B8E7B;
  --aob-c-terracotta: #C2703D;
  --aob-c-rice: #F7F3EB;
  --aob-c-ink: #14253D;
  --aob-c-muted: #AAB8C5;
  --aob-c-line: rgba(201, 160, 99, 0.18);
  --aob-header-w: 272px;
  --aob-header-h: 64px;
  --aob-max-w: 1240px;
  --aob-gutter: clamp(16px, 3.5vw, 32px);
  --aob-font-head: "Source Han Sans CN", "Noto Sans CJK SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --aob-font-body: "Source Han Serif CN", "Noto Serif CJK SC", "Songti SC", "SimSun", Georgia, serif;
  --aob-font-mono: "SF Mono", "JetBrains Mono", "Consolas", "Menlo", monospace;
  --aob-ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ============ 2. Reset & base ============ */
*,
*::before,
*::after {
  box-sizing: border-box;
}

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

ul,
ol {
  padding: 0;
}

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

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

html {
  scroll-behavior: smooth;
}

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

body {
  font-family: var(--aob-font-body);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--aob-c-ink);
  background-color: var(--aob-c-rice);
  background-image:
    linear-gradient(rgba(201, 160, 99, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(201, 160, 99, 0.05) 1px, transparent 1px);
  background-size: 48px 48px;
  min-height: 100vh;
  padding-left: var(--aob-header-w);
  -webkit-font-smoothing: antialiased;
}

::selection {
  background: var(--aob-c-gold);
  color: var(--aob-c-primary);
}

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

#main-content {
  scroll-margin-top: 24px;
}

/* ============ 3. Skip link ============ */
.skip-link {
  position: fixed;
  top: -120px;
  left: calc(var(--aob-header-w) + 16px);
  z-index: 1000;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 12px 22px;
  background: var(--aob-c-orange);
  color: #fff;
  font-family: var(--aob-font-head);
  font-weight: 700;
  font-size: 0.88rem;
  text-decoration: none;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.22);
  transition: top 0.2s var(--aob-ease);
}

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

/* ============ 4. Header — desktop side rail ============ */
.aob-header {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 120;
  width: var(--aob-header-w);
  height: 100vh;
  background-color: var(--aob-c-primary);
  background-image:
    linear-gradient(var(--aob-c-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--aob-c-line) 1px, transparent 1px);
  background-size: 26px 26px;
  border-right: 1px solid var(--aob-c-gold);
  overflow-y: auto;
}

.aob-header__inner {
  display: flex;
  flex-direction: column;
  min-height: 100%;
  padding: 28px 26px 24px;
}

.aob-header__top {
  display: block;
  margin-bottom: 48px;
}

.aob-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--aob-c-rice);
  transition: color 0.2s var(--aob-ease);
}

.aob-brand:hover {
  color: var(--aob-c-gold);
}

.aob-brand__mark {
  position: relative;
  display: inline-block;
  width: 30px;
  height: 30px;
  flex: 0 0 auto;
  background: var(--aob-c-primary);
  border: 1px solid var(--aob-c-gold);
  overflow: hidden;
}

.aob-brand__mark::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 6px;
  background: var(--aob-c-gold);
}

.aob-brand__mark::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(to top right, transparent 43%, var(--aob-c-gold) 43%, var(--aob-c-gold) 49%, transparent 49%);
}

.aob-brand__text {
  font-family: var(--aob-font-head);
  font-weight: 700;
  font-size: 1.3rem;
  letter-spacing: 0.12em;
  line-height: 1;
}

.aob-nav-toggle {
  display: none;
}

.aob-nav {
  display: flex;
  flex-direction: column;
  flex: 1;
}

.aob-nav__list {
  list-style: none;
  margin: 0 0 32px;
  counter-reset: aob-nav;
}

.aob-nav__item {
  counter-increment: aob-nav;
}

.aob-nav__link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 13px 6px;
  color: rgba(247, 243, 235, 0.72);
  font-family: var(--aob-font-head);
  font-weight: 600;
  font-size: 1rem;
  letter-spacing: 0.04em;
  text-decoration: none;
  border-bottom: 1px solid var(--aob-c-line);
  transition: color 0.2s var(--aob-ease), padding-left 0.2s var(--aob-ease);
}

.aob-nav__link::before {
  content: "0" counter(aob-nav);
  font-family: var(--aob-font-mono);
  font-size: 0.7rem;
  font-weight: 400;
  line-height: 1;
  color: var(--aob-c-gold);
  opacity: 0.55;
  min-width: 24px;
}

.aob-nav__link:hover {
  color: var(--aob-c-rice);
  padding-left: 10px;
}

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

.aob-nav__link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--aob-c-gold);
}

.aob-nav__foot {
  margin-top: auto;
  padding-top: 20px;
  border-top: 1px solid var(--aob-c-line);
}

.aob-nav__quick {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 12px 18px;
  background: var(--aob-c-orange);
  color: #fff;
  font-family: var(--aob-font-head);
  font-weight: 700;
  font-size: 0.92rem;
  letter-spacing: 0.04em;
  text-decoration: none;
  transition: background 0.2s var(--aob-ease);
}

.aob-nav__quick:hover {
  background: #e25828;
  color: #fff;
}

.aob-nav__quick-dot {
  width: 8px;
  height: 8px;
  flex: 0 0 auto;
  background: #fff;
}

.aob-nav__meta {
  margin-top: 20px;
  font-family: var(--aob-font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.12em;
  color: rgba(170, 184, 197, 0.7);
}

/* ============ 5. Header mobile drawer ============ */
@media (max-width: 1023px) {
  body {
    padding-top: var(--aob-header-h);
    padding-left: 0;
  }

  #main-content {
    scroll-margin-top: calc(var(--aob-header-h) + 16px);
  }

  .skip-link {
    left: 16px;
  }

  .aob-header {
    width: 100%;
    height: var(--aob-header-h);
    border-right: none;
    border-bottom: 1px solid var(--aob-c-gold);
    overflow: visible;
  }

  .aob-header__inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    min-height: 0;
    height: 100%;
    padding: 0 var(--aob-gutter);
  }

  .aob-header__top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    height: 100%;
    margin-bottom: 0;
  }

  .aob-nav-toggle {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    width: 48px;
    height: 48px;
    padding: 0;
    border: 1px solid var(--aob-c-line);
  }

  .aob-nav-toggle__bar {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--aob-c-gold);
    transition: transform 0.2s var(--aob-ease), opacity 0.2s var(--aob-ease);
  }

  .aob-nav-toggle__label {
    font-family: var(--aob-font-mono);
    font-size: 0.58rem;
    letter-spacing: 0.14em;
    line-height: 1;
    color: var(--aob-c-gold);
    margin-top: 2px;
  }

  .aob-nav-toggle[aria-expanded="true"] .aob-nav-toggle__bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

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

  .aob-nav-toggle[aria-expanded="true"] .aob-nav-toggle__bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .aob-nav {
    position: fixed;
    top: var(--aob-header-h);
    left: 0;
    bottom: 0;
    z-index: 130;
    flex: none;
    width: min(360px, 88vw);
    padding: 28px 24px;
    background-color: var(--aob-c-primary);
    background-image:
      linear-gradient(var(--aob-c-line) 1px, transparent 1px),
      linear-gradient(90deg, var(--aob-c-line) 1px, transparent 1px);
    background-size: 26px 26px;
    border-right: 1px solid var(--aob-c-gold);
    box-shadow: 8px 0 32px rgba(0, 0, 0, 0.35);
    overflow-y: auto;
    transform: translateX(-100%);
    visibility: hidden;
    transition: transform 0.22s var(--aob-ease), visibility 0.22s var(--aob-ease);
  }

  .aob-nav[data-open] {
    transform: translateX(0);
    visibility: visible;
  }

  body.aob-menu-open {
    overflow: hidden;
  }

  body.aob-menu-open::after {
    content: "";
    position: fixed;
    inset: 0;
    z-index: 110;
    background: rgba(11, 27, 63, 0.55);
  }
}

/* ============ 6. Footer ============ */
.aob-footer {
  position: relative;
  background: var(--aob-c-primary);
  color: rgba(247, 243, 235, 0.82);
  font-family: var(--aob-font-body);
  font-size: 0.9rem;
  line-height: 1.6;
}

.aob-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--aob-c-gold) 0%, var(--aob-c-line) 20%, var(--aob-c-line) 80%, var(--aob-c-gold) 100%);
}

.aob-footer a {
  color: rgba(247, 243, 235, 0.82);
  text-decoration: none;
  transition: color 0.2s var(--aob-ease);
}

.aob-footer a:hover {
  color: var(--aob-c-gold);
}

.aob-footer__inner {
  max-width: var(--aob-max-w);
  margin: 0 auto;
  padding: 56px var(--aob-gutter) 28px;
}

.aob-footer__grid {
  display: grid;
  gap: 40px;
  padding-bottom: 44px;
}

.aob-footer__about {
  margin-top: 18px;
  max-width: 32em;
  font-size: 0.88rem;
  line-height: 1.75;
  color: rgba(247, 243, 235, 0.65);
}

.aob-footer__title {
  margin-bottom: 14px;
  padding-bottom: 8px;
  font-family: var(--aob-font-head);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--aob-c-gold);
  border-bottom: 1px solid var(--aob-c-line);
}

.aob-footer__contact-list {
  list-style: none;
  margin: 0 0 12px;
}

.aob-footer__contact-list li {
  padding: 4px 0;
  font-size: 0.85rem;
  color: rgba(247, 243, 235, 0.72);
}

.aob-footer__time {
  padding-top: 10px;
  border-top: 1px solid var(--aob-c-line);
  font-family: var(--aob-font-mono);
  font-size: 0.72rem;
  color: var(--aob-c-muted);
}

.aob-footer__nav-list {
  list-style: none;
}

.aob-footer__nav-list li + li {
  border-top: 1px solid var(--aob-c-line);
}

.aob-footer__nav-list a {
  display: block;
  padding: 10px 2px;
  font-size: 0.9rem;
}

.aob-footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 28px;
  padding-top: 20px;
  border-top: 1px solid var(--aob-c-line);
  font-family: var(--aob-font-mono);
  font-size: 0.72rem;
  color: var(--aob-c-muted);
}

.aob-footer__copy,
.aob-footer__icp {
  color: inherit;
}

.aob-footer__trust {
  color: var(--aob-c-muted);
  opacity: 0.82;
}

@media (min-width: 760px) {
  .aob-footer__grid {
    grid-template-columns: 1.6fr 1.2fr 1fr;
    gap: 48px;
  }
}

/* ============ 7. Typography & components ============ */
.aob-main {
  min-height: 70vh;
}

.aob-container {
  width: 100%;
  max-width: var(--aob-max-w);
  margin-inline: auto;
  padding-inline: var(--aob-gutter);
}

.aob-section {
  padding-block: clamp(40px, 7vw, 72px);
}

.aob-h1,
.aob-h2,
.aob-h3 {
  font-family: var(--aob-font-head);
  line-height: 1.22;
  color: var(--aob-c-ink);
  letter-spacing: 0.02em;
}

.aob-h1 {
  font-size: clamp(1.75rem, 3.6vw, 2.75rem);
  font-weight: 800;
}

.aob-h2 {
  font-size: clamp(1.35rem, 2.6vw, 2rem);
  font-weight: 700;
}

.aob-h3 {
  font-size: 1.2rem;
  font-weight: 700;
}

.aob-kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--aob-font-head);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--aob-c-primary);
}

.aob-kicker::before {
  content: "";
  width: 26px;
  height: 1px;
  background: var(--aob-c-gold);
}

.aob-kicker--on-dark {
  color: var(--aob-c-gold);
}

.aob-data {
  font-family: var(--aob-font-mono);
  font-size: 0.88rem;
  line-height: 1.45;
  color: var(--aob-c-rock);
}

.aob-data--strong {
  color: var(--aob-c-primary);
  font-weight: 600;
}

.aob-list {
  padding-left: 1.15em;
  list-style: disc;
}

.aob-list li {
  padding-left: 0.3em;
  margin-bottom: 0.5em;
  line-height: 1.7;
}

/* ============ 8. Buttons ============ */
.aob-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 12px 22px;
  border: none;
  border-radius: 0;
  background: var(--aob-c-orange);
  color: #fff;
  font-family: var(--aob-font-head);
  font-weight: 700;
  font-size: 0.92rem;
  line-height: 1;
  text-decoration: none;
  transition: background 0.2s var(--aob-ease), color 0.2s var(--aob-ease), border-color 0.2s var(--aob-ease);
}

.aob-btn:hover {
  background: #d9562b;
  color: #fff;
}

.aob-btn--ghost {
  background: transparent;
  border: 1px solid var(--aob-c-gold);
  color: var(--aob-c-gold);
}

.aob-btn--ghost:hover {
  background: rgba(201, 160, 99, 0.1);
  color: var(--aob-c-gold);
}

.aob-btn--small {
  min-height: 36px;
  padding: 8px 14px;
  font-size: 0.82rem;
}

/* ============ 9. Breadcrumbs ============ */
.aob-breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  padding: 18px 0;
  font-family: var(--aob-font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.06em;
  color: var(--aob-c-muted);
}

.aob-breadcrumbs a {
  color: var(--aob-c-rock);
  text-decoration: none;
}

.aob-breadcrumbs a:hover {
  color: var(--aob-c-terracotta);
}

.aob-breadcrumbs__sep {
  color: var(--aob-c-gold);
  opacity: 0.7;
}

.aob-breadcrumbs [aria-current="page"] {
  color: var(--aob-c-ink);
}

@media (max-width: 767px) {
  .aob-breadcrumbs {
    font-size: 0.7rem;
  }
}

/* ============ 10. Grids & panels ============ */
.aob-grid {
  display: grid;
  gap: 24px;
  grid-template-columns: minmax(0, 1fr);
}

@media (min-width: 768px) {
  .aob-grid--2 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (min-width: 1024px) {
  .aob-grid--aside {
    grid-template-columns: minmax(0, 1fr) 300px;
  }
}

.aob-panel {
  position: relative;
  padding: 24px;
  background: rgba(255, 255, 255, 0.55);
  border: 1px solid var(--aob-c-line);
}

.aob-panel::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 32px;
  height: 2px;
  background: var(--aob-c-gold);
}

.aob-note {
  padding: 20px 22px;
  background: rgba(201, 160, 99, 0.08);
  border-left: 2px solid var(--aob-c-gold);
  font-size: 0.92rem;
  line-height: 1.7;
  color: var(--aob-c-rock);
}

.aob-tag {
  display: inline-block;
  padding: 4px 10px;
  font-family: var(--aob-font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--aob-c-rock);
  border: 1px solid var(--aob-c-line);
  background: rgba(247, 243, 235, 0.3);
}

.aob-tag--gold {
  border-color: var(--aob-c-gold);
  color: var(--aob-c-primary);
}

.aob-tag--moss {
  border-color: var(--aob-c-moss);
  color: var(--aob-c-moss);
}

.aob-tag--terracotta {
  border-color: var(--aob-c-terracotta);
  color: var(--aob-c-terracotta);
}

/* ============ 11. Table ============ */
.aob-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--aob-c-line);
}

.aob-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
}

.aob-table th {
  padding: 12px 14px;
  text-align: left;
  font-family: var(--aob-font-head);
  font-weight: 700;
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  color: var(--aob-c-primary);
  border-bottom: 2px solid var(--aob-c-gold);
}

.aob-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--aob-c-line);
  vertical-align: top;
}

/* ============ 12. Figure & image containers ============ */
.aob-figure {
  position: relative;
  overflow: hidden;
  aspect-ratio: 4 / 3;
  background: rgba(201, 160, 99, 0.08);
  border: 1px solid var(--aob-c-line);
}

.aob-figure--wide {
  aspect-ratio: 16 / 9;
}

.aob-figure--tall {
  aspect-ratio: 3 / 4;
}

.aob-figure::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background-image:
    linear-gradient(var(--aob-c-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--aob-c-line) 1px, transparent 1px);
  background-size: 22px 22px;
}

.aob-figure img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.aob-figure__caption {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  padding: 6px 10px;
  background: var(--aob-c-primary);
  color: var(--aob-c-gold);
  font-family: var(--aob-font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
}

/* ============ 13. Scroll reveal ============ */
.aob-js [data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.22s var(--aob-ease), transform 0.22s var(--aob-ease);
}

.aob-js [data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============ 14. Reduced motion ============ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

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