/* ============================================================
   成分复杂 · 子页身份条(identity bar)
   给 tools / echo / mystery 等子页统一的"品牌皮肤层"：
   顶部身份条 + 明暗切换。各页保留自身内容气质。
   ============================================================ */

/* —— 家族 tokens(与主页同源；子页可引用 var(--paper) 等) —— */
:root {
  --paper: #F5F5F3;
  --paper-deep: #ECECEA;
  --card: #FBFBFA;
  --ink: #201E1B;
  --ink-soft: #55524B;
  --ink-faint: #756F66;
  --accent: #B0212A;
  --accent-deep: #8F1A22;
  --line: #DDDCD7;
  --surface-hover: rgba(255,255,255,.55);
  --font-display: "Songti SC", "Noto Serif SC", "Source Han Serif SC", "STSong", Georgia, "Times New Roman", serif;
  --font-body: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  color-scheme: light;
}
html[data-theme="dark"] {
  --paper: #191814;
  --paper-deep: #21201B;
  --card: #24221C;
  --ink: #EAE4D7;
  --ink-soft: #BFB7A6;
  --ink-faint: #9A9182;
  --accent: #E0564D;
  --accent-deep: #B83C35;
  --line: #34322A;
  --surface-hover: rgba(255,255,255,.05);
  color-scheme: dark;
}

/* —— 身份条 —— */
.cf-top {
  position: fixed; top: 0; left: 0; right: 0; z-index: 900; /* 高于页面内容，低于全屏遮罩 */
  display: flex; align-items: center; justify-content: space-between;
  height: 48px; padding: 0 18px;
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  -webkit-backdrop-filter: blur(10px); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
  box-sizing: border-box;
}
.cf-brand {
  display: inline-flex; align-items: center; gap: 9px;
  color: var(--ink); text-decoration: none;
  font-family: var(--font-display); font-weight: 700; font-size: 15px; letter-spacing: .05em;
}
.cf-brand img {
  width: 22px; height: 22px; border-radius: 50%;
  object-fit: cover; object-position: top center;
  border: 1px solid var(--line);
}
.cf-brand:hover { color: var(--accent); }
.cf-crumb {
  margin-left: 14px; padding-left: 14px; border-left: 1px solid var(--line);
  font-family: var(--font-mono); font-size: 11px; letter-spacing: .14em;
  color: var(--ink-faint); text-transform: uppercase;
}
.cf-back {
  font-family: var(--font-body); font-size: 13px; color: var(--ink-soft);
  text-decoration: none; letter-spacing: .04em;
  transition: color .2s ease;
}
.cf-back:hover { color: var(--accent); }
.cf-back::before { content: "⇠ "; }
.cf-toggle {
  width: 32px; height: 32px; position: relative;
  display: inline-grid; place-items: center; padding: 0;
  border-radius: 50%; border: 1px solid var(--line);
  background: transparent; color: var(--ink-soft); cursor: pointer;
  transition: color .25s ease, border-color .25s ease, background .25s ease;
}
.cf-toggle:hover { color: var(--accent); border-color: var(--accent); background: var(--surface-hover); }
.cf-toggle .ic {
  position: absolute; inset: 0; margin: auto; width: 16px; height: 16px;
  transition: opacity .4s ease, transform .6s cubic-bezier(.22,.61,.36,1);
}
.cf-toggle .ic-sun  { opacity: 0; transform: rotate(-120deg) scale(.35); }
.cf-toggle .ic-moon { opacity: 1; transform: rotate(0) scale(1); }
:root[data-theme="dark"] .cf-toggle .ic-sun { opacity: 1; transform: rotate(0) scale(1); }
:root[data-theme="dark"] .cf-toggle .ic-moon { opacity: 0; transform: rotate(130deg) scale(.35); }

/* 页面主体留出身份条高度(有 .cf-page 的容器会处理,否则由各页自行 padding) */
body.cf-pad { padding-top: 48px; }

/* 丝滑切换 */
html.theme-switching, html.theme-switching *,
html.theme-switching *::before, html.theme-switching *::after {
  transition: background-color .5s ease, color .5s ease, border-color .5s ease,
              box-shadow .5s ease !important;
}

/* 键盘可达 */
.cf-toggle:focus-visible, .cf-brand:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

@media (prefers-reduced-motion: reduce) {
  .cf-toggle .ic, html.theme-switching *, html.theme-switching *::before, html.theme-switching *::after {
    transition: none !important;
  }
}

/* 移动端收窄 */
@media (max-width: 520px) {
  .cf-crumb { display: none; }
  .cf-top { padding: 0 12px; }
}