/* ============================================================
   博乐CN · /assets/site.css
   共享外壳：reset / 变量 / 中文排版 / 页头 / 页脚 / 通用组件
   ============================================================ */

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

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

body {
  margin: 0;
  min-height: 100vh;
}

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

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

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

p,
figure,
blockquote {
  margin: 0;
}

table {
  border-collapse: collapse;
}

/* ---------- 2. 变量 ---------- */
:root {
  /* 色彩 */
  --paper: #FFF8F0;
  --sand: #F2E6D6;
  --ink: #101C33;
  --flare: #FF6B1A;
  --amber: #F5B73C;
  --flare-soft: #FFA23A;
  --cyan: #0E7C86;
  --mist: #C4CFE0;
  --slate: #2A3B57;
  --ember: #D8451F;

  /* 排版 */
  --font-display: "Noto Sans SC", "Source Han Sans SC", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace,
    SFMono-Regular, Menlo, Consolas, monospace;

  --fs-display: clamp(40px, 7.2vw, 88px);
  --fs-h2: clamp(30px, 4vw, 56px);
  --fs-h3: clamp(22px, 2.4vw, 32px);
  --fs-lead: 20px;
  --fs-body: 16px;

  /* 网格与间距 */
  --shell-max: 1320px;
  --pad: 64px;
  --gutter: 24px;
  --hair: 1px solid var(--mist);
  --hair-soft: 1px solid rgba(196, 207, 224, 0.62);

  --ease: cubic-bezier(0.2, 0.7, 0.3, 1);
  --dur: 240ms;
}

/* ---------- 3. 基础排版 ---------- */
body {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  font-weight: 400;
  line-height: 1.75;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    linear-gradient(to right, rgba(196, 207, 224, 0.16) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(196, 207, 224, 0.16) 1px, transparent 1px);
  background-size: 64px 64px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.14;
  color: var(--ink);
}

h1 { font-size: var(--fs-display); }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }
h4 { font-size: var(--fs-lead); letter-spacing: 0; }

a {
  color: var(--ink);
  text-decoration-color: var(--flare);
  text-underline-offset: 3px;
}

a:hover {
  color: var(--ember);
}

strong,
b {
  font-weight: 700;
}

code,
kbd,
samp {
  font-family: var(--font-mono);
  font-size: 0.92em;
}

#main-content {
  scroll-margin-top: 8px;
}

/* ---------- 4. 无障碍 ---------- */
:where(a, button, [tabindex], input, select, textarea):focus-visible {
  outline: 2px solid var(--flare);
  outline-offset: 3px;
}

:where(a, button):focus:not(:focus-visible) {
  outline: none;
}

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

.skip-link {
  position: fixed;
  top: -120px;
  left: 16px;
  z-index: 120;
  display: inline-block;
  padding: 12px 20px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--paper);
  background: var(--ink);
  border-left: 3px solid var(--flare);
  text-decoration: none;
  transition: top 180ms var(--ease);
}

.skip-link:focus,
.skip-link:focus-visible {
  top: 10px;
  color: var(--paper);
}

/* ---------- 5. 阅读进度 ---------- */
.read-progress {
  position: fixed;
  inset: 0 0 auto 0;
  height: 2px;
  z-index: 110;
  pointer-events: none;
}

.read-progress__bar {
  display: block;
  height: 100%;
  width: 100%;
  background: linear-gradient(90deg, var(--flare), var(--amber));
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform 120ms linear;
}

/* ---------- 6. 页头 ---------- */
.site-header {
  position: relative;
  z-index: 20;
  background: var(--paper);
  border-bottom: var(--hair);
}

.header-rail {
  background: var(--ink);
  color: var(--paper);
}

.header-rail__inner {
  display: flex;
  align-items: center;
  gap: 16px;
  min-height: 34px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.header-rail__mark {
  color: var(--amber);
  font-weight: 700;
  letter-spacing: 0.2em;
}

.header-rail__tagline {
  color: var(--mist);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.header-rail__scan {
  margin-left: auto;
  color: var(--paper);
  text-decoration: none;
  padding-bottom: 1px;
  border-bottom: 1px solid var(--flare);
  transition: color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.header-rail__scan:hover {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

.masthead {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-block: 24px 22px;
}

.masthead__brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  color: var(--ink);
  text-decoration: none;
}

.masthead__brand:hover {
  color: var(--ink);
}

.masthead__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(24px, 5vw, 32px);
  letter-spacing: -0.02em;
  line-height: 1;
}

/* 焰橙索引符：右下角带缺口的方形 */
.index-glyph {
  display: inline-block;
  flex: none;
  width: 14px;
  height: 14px;
  background: var(--flare);
  clip-path: polygon(0 0, 100% 0, 100% 60%, 60% 60%, 60% 100%, 0 100%);
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  align-items: center;
  gap: 9px;
  padding: 9px 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--ink);
  background: transparent;
  border: 1px solid var(--mist);
  border-radius: 0;
  cursor: pointer;
  transition: border-color var(--dur) var(--ease),
    background-color var(--dur) var(--ease);
}

.nav-toggle:hover {
  border-color: var(--flare);
  background: var(--sand);
}

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 16px;
  height: 2px;
  background: var(--ink);
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  background: var(--ink);
}

.nav-toggle__bars::before { top: -5px; }
.nav-toggle__bars::after { top: 5px; }

.nav-toggle__text {
  line-height: 1;
}

/* 居中刊头导航 */
.site-nav {
  background: var(--paper);
  border-top: var(--hair);
}

.site-nav__inner {
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding-inline: var(--pad);
}

.site-nav__list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: stretch;
  gap: clamp(14px, 2.6vw, 40px);
}

.site-nav__link {
  display: block;
  padding: 15px 2px 13px;
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--slate);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.site-nav__link:hover {
  color: var(--ink);
  border-bottom-color: var(--amber);
}

.site-nav__link[aria-current="page"] {
  color: var(--ink);
  font-weight: 700;
  border-bottom-color: var(--flare);
}

/* ---------- 7. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(60px, 9vw, 120px);
  background: var(--ink);
  color: var(--mist);
}

.site-footer::before {
  content: "";
  display: block;
  height: 2px;
  background: var(--flare);
}

.footer-inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.5fr 1.6fr;
  gap: clamp(24px, 3vw, 44px);
  padding-block: 56px 40px;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: flex-start;
}

.footer-brand__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 32px;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.footer-brand__tagline {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--mist);
}

.footer-col {
  min-width: 0;
}

.footer-col__title {
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: var(--hair-soft);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.footer-col__list {
  display: grid;
  gap: 9px;
}

.footer-col__link {
  display: inline-block;
  padding-bottom: 1px;
  font-size: 15px;
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.footer-col__link:hover {
  color: var(--paper);
  border-bottom-color: var(--flare);
}

.footer-col__text {
  margin-bottom: 8px;
  font-size: 14px;
  line-height: 1.72;
  color: var(--mist);
}

.footer-col__text:last-child {
  margin-bottom: 0;
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 28px;
  padding-block: 18px 26px;
  border-top: var(--hair-soft);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

.footer-base__year {
  font-variant-numeric: tabular-nums;
}

.footer-base__coord {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-left: auto;
}

.footer-base__rule {
  display: inline-block;
  width: 28px;
  height: 1px;
  background: var(--flare);
}

/* ---------- 8. 通用布局 ---------- */
.shell {
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding-inline: var(--pad);
}

.stack {
  display: flex;
  flex-direction: column;
  gap: var(--stack-gap, 16px);
}

.grid {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
}

.grid--7-5 { grid-template-columns: 7fr 5fr; }
.grid--8-4 { grid-template-columns: 8fr 4fr; }
.grid--12  { grid-template-columns: repeat(12, 1fr); }

/* ---------- 9. 通用组件 ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--slate);
}

.num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--flare);
}

.annotation {
  writing-mode: vertical-rl;
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--slate);
  text-orientation: mixed;
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  padding-top: 16px;
  border-top: var(--hair);
}

.band {
  display: flex;
  align-items: center;
  gap: 16px;
  min-height: 48px;
  padding: 10px var(--pad);
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
}

.band--flare {
  background: var(--flare);
  color: var(--paper);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 22px;
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--ink);
  text-decoration: none;
  background: transparent;
  border: 1px solid var(--ink);
  border-radius: 0;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease),
    color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.btn--flare {
  background: var(--flare);
  border-color: var(--flare);
  color: var(--paper);
}

.btn--flare:hover {
  background: var(--amber);
  border-color: var(--amber);
  color: var(--ink);
}

.btn--ink {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
}

.btn--ink:hover {
  background: var(--slate);
  border-color: var(--slate);
  color: var(--paper);
}

.btn--ghost:hover {
  border-color: var(--flare);
  color: var(--ember);
  background: rgba(245, 183, 60, 0.14);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 20px 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--slate);
}

.breadcrumb a {
  color: var(--slate);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.breadcrumb a:hover {
  color: var(--ink);
  border-bottom-color: var(--flare);
}

.breadcrumb__sep {
  color: var(--mist);
}

.prose {
  max-width: 64ch;
  font-size: var(--fs-body);
  line-height: 1.78;
  color: var(--ink);
}

.prose > * + * {
  margin-top: 1.05em;
}

.prose h3 {
  margin-top: 1.8em;
}

.prose ul,
.prose ol {
  padding-left: 1.4em;
  list-style: disc;
}

.prose ol {
  list-style: decimal;
}

.prose li + li {
  margin-top: 0.4em;
}

/* 图片容器基础规则 */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  background: var(--sand);
  border: var(--hair);
  aspect-ratio: 4 / 3;
}

.media-frame > img,
.media-frame > picture > img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame--wide   { aspect-ratio: 16 / 9; }
.media-frame--tall   { aspect-ratio: 3 / 4; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-frame__caption {
  position: absolute;
  left: 0;
  bottom: 0;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--paper);
  background: var(--ink);
}

/* 状态面板 */
.console {
  padding: 18px 20px 20px;
  background: rgba(255, 248, 240, 0.92);
  border: var(--hair);
}

.console__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: var(--hair);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--slate);
}

.console__list {
  display: grid;
  gap: 9px;
}

.console__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  font-size: 14px;
  color: var(--ink);
}

.console__row b {
  font-family: var(--font-mono);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--flare);
}

.console__dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  margin-right: 8px;
  vertical-align: middle;
  background: var(--cyan);
}

/* 章节高亮与章节导航 */
[data-chapter] {
  scroll-margin-top: 24px;
}

.chapter-marker {
  display: inline-block;
  width: 10px;
  height: 10px;
  background: var(--mist);
  transition: background-color var(--dur) var(--ease);
}

[data-chapter].is-active .chapter-marker {
  background: var(--flare);
}

[data-chapter-link] {
  display: block;
  padding: 6px 0 6px 10px;
  font-size: 14px;
  color: var(--slate);
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

[data-chapter-link]:hover {
  color: var(--ink);
}

[data-chapter-link][aria-current="true"] {
  color: var(--ink);
  font-weight: 700;
  border-left-color: var(--flare);
}

/* ---------- 10. 响应式 ---------- */
@media (max-width: 1080px) {
  :root { --pad: 40px; }

  .footer-inner {
    grid-template-columns: 1.4fr 1fr 1fr;
    row-gap: 36px;
  }
}

@media (max-width: 900px) {
  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    display: none;
    border-bottom: var(--hair);
  }

  .site-nav[data-open="true"] {
    display: block;
  }

  .site-nav__inner {
    padding-inline: var(--pad);
  }

  .site-nav__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 0;
    padding-block: 4px 8px;
  }

  .site-nav__item {
    border-bottom: var(--hair-soft);
  }

  .site-nav__item:last-child {
    border-bottom: 0;
  }

  .site-nav__link {
    padding: 14px 2px;
    font-size: 16px;
    border-bottom: 0;
  }

  .site-nav__link:hover {
    border-bottom-color: transparent;
  }

  .site-nav__link[aria-current="page"] {
    color: var(--ember);
    border-bottom: 0;
  }

  .grid--7-5,
  .grid--8-4,
  .grid--12 {
    grid-template-columns: 1fr;
  }

  .footer-base__coord {
    margin-left: 0;
  }
}

@media (max-width: 680px) {
  :root { --pad: 20px; }

  .header-rail__tagline {
    display: none;
  }

  .header-rail__inner {
    min-height: 32px;
    font-size: 11px;
  }

  .masthead {
    padding-block: 18px 16px;
  }

  .footer-inner {
    grid-template-columns: 1fr 1fr;
    padding-block: 40px 32px;
    row-gap: 32px;
  }

  .footer-brand {
    grid-column: 1 / -1;
  }

  .footer-base {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    font-size: 11px;
  }
}

@media (max-width: 420px) {
  .footer-inner {
    grid-template-columns: 1fr;
  }
}

/* ---------- 11. 减弱动效 ---------- */
@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;
  }

  .read-progress__bar {
    transition: none;
  }
}