/* =========================================================================
   序 XU · Base
   Reset / 排版 / 通用组件（按钮、标签、头像、时间轴原子、图标）/ 入场动画
   应用壳层与具体视图样式在 app.css / views.css 中。
   ========================================================================= */

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

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--dur-3) var(--ease), color var(--dur-3) var(--ease);
  min-height: 100vh;
}

h1, h2, h3, h4, p, ul, ol, figure, blockquote { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg { display: block; max-width: 100%; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
input, textarea, select { font: inherit; color: inherit; }

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--dur-1) var(--ease), opacity var(--dur-1) var(--ease);
}

::selection { background: var(--accent-soft); color: var(--ink); }

:focus-visible {
  outline: 1px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--r-xs);
}

.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

/* ---------- 图标 ---------- */
.icon {
  width: 18px; height: 18px;
  fill: none; stroke: currentColor;
  stroke-width: 1.4; stroke-linecap: round; stroke-linejoin: round;
  flex: none;
}
.icon--sm { width: 16px; height: 16px; }
.icon--lg { width: 22px; height: 22px; }

.icon-btn {
  display: inline-grid;
  place-items: center;
  width: 36px; height: 36px;
  border-radius: var(--r-sm);
  color: var(--ink-2);
  transition: color var(--dur-1) var(--ease), background-color var(--dur-1) var(--ease);
}
.icon-btn:hover { color: var(--ink); background: var(--ghost); }
.icon-btn .icon { display: block; margin: auto; }
.icon-btn:disabled { opacity: .42; cursor: default; pointer-events: none; }

/* 主题图标：按当前主题显示其一 */
.theme-toggle .icon--moon { display: none; }
:root[data-theme="dark"] .theme-toggle .icon--sun { display: none; }
:root[data-theme="dark"] .theme-toggle .icon--moon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle .icon--sun { display: none; }
  :root:not([data-theme="light"]) .theme-toggle .icon--moon { display: block; }
}

/* ---------- 排版工具 ---------- */
.eyebrow {
  font-size: var(--fs-micro);
  letter-spacing: var(--ls-wide);
  text-transform: uppercase;
  color: var(--ink-3);
}
.hairline { height: 1px; background: var(--line); border: 0; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  height: 42px;
  padding: 0 1.35rem;
  border-radius: var(--r-pill);
  border: 1px solid transparent;
  font-size: var(--fs-sm);
  font-weight: 500;
  letter-spacing: .03em;
  white-space: nowrap;
  transition: background-color var(--dur-2) var(--ease),
              color var(--dur-2) var(--ease),
              border-color var(--dur-2) var(--ease),
              transform var(--dur-2) var(--ease),
              opacity var(--dur-2) var(--ease);
}
.btn--sm { height: 34px; padding: 0 .95rem; font-size: var(--fs-xs); }
.btn--lg { height: 50px; padding: 0 2.1rem; font-size: var(--fs-body); }
.btn--block { width: 100%; }

.btn--solid { background: var(--ink); color: var(--paper); }
.btn--solid:hover { background: var(--accent); }
.btn--quiet { color: var(--ink-2); border-color: var(--line-2); }
.btn--quiet:hover { color: var(--ink); border-color: var(--ink); }
.btn--ghost { color: var(--ink-2); }
.btn--ghost:hover { color: var(--ink); background: var(--ghost); }
.btn--danger { color: var(--danger); border-color: color-mix(in srgb, var(--danger) 38%, var(--line)); }
.btn--danger:hover { background: color-mix(in srgb, var(--danger) 12%, transparent); color: var(--danger); border-color: var(--danger); }
.btn[disabled] { opacity: .45; pointer-events: none; }

.btn__arrow {
  width: 14px; height: 8px;
  margin-left: 0; opacity: 0; transform: translateX(-4px);
  transition: opacity var(--dur-2) var(--ease), transform var(--dur-2) var(--ease), margin-left var(--dur-2) var(--ease);
}
.btn:hover .btn__arrow, .btn:focus-visible .btn__arrow {
  opacity: 1; transform: translateX(0); margin-left: .5rem;
}

/* ---------- 标签 / 头像 ---------- */
.chip {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  height: 26px;
  padding: 0 .625rem;
  border: 1px solid var(--line);
  border-radius: var(--r-pill);
  font-size: var(--fs-xs);
  color: var(--ink-2);
  letter-spacing: .02em;
  white-space: nowrap;
}
.chip--place::before {
  content: ""; width: 4px; height: 4px; border-radius: 50%; background: var(--accent); opacity: .8;
}
.chip--note { color: var(--ink-3); }
.chip--link { color: var(--accent); border-color: var(--accent-line); }
.chip--link:hover { background: var(--accent-soft); }

.avatar {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px; height: 30px;
  border-radius: 50%;
  border: 1px solid var(--line-2);
  background: var(--paper-2);
  font-size: var(--fs-xs);
  color: var(--ink-2);
  letter-spacing: 0;
  flex: none;
  overflow: hidden;
  font-weight: 500;
  line-height: 1;
}
.avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.avatar--xs { width: 22px; height: 22px; font-size: 10px; }
.avatar--sm { width: 26px; height: 26px; font-size: 11px; }
.avatar--md { width: 36px; height: 36px; font-size: var(--fs-sm); }
.avatar--me { background: var(--ink); color: var(--paper); border-color: var(--ink); }

.avatar-stack { display: inline-flex; align-items: center; }
.avatar-stack .avatar { margin-left: -8px; box-shadow: 0 0 0 2px var(--paper); }
.avatar-stack .avatar:first-child { margin-left: 0; }
.avatar-stack .avatar--more {
  background: var(--paper-3); color: var(--ink-3); font-size: 9px; font-weight: 500;
}

/* ---------- 时间轴原子（被 Timeline 视图复用） ---------- */
.tl { position: relative; }
.tl__row {
  position: relative;
  display: grid;
  grid-template-columns: 4.5rem 1px 1fr;
  align-items: baseline;
  column-gap: 1.1rem;
  padding-block: .55rem;
}
.tl__time {
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  color: var(--ink-3);
  letter-spacing: .02em;
  font-variant-numeric: tabular-nums;
}
.tl__dot {
  position: relative; align-self: stretch;
  background: var(--line-2); transform-origin: top;
}
.tl__dot::after {
  content: ""; position: absolute; top: .62em; left: 50%;
  width: 5px; height: 5px; border-radius: 50%;
  background: var(--paper); border: 1px solid var(--line-2);
  transform: translateX(-50%);
}
.tl__row:first-child .tl__dot::after { background: var(--accent); border-color: var(--accent); }
.tl__text { color: var(--ink); }

/* ---------- 占位 ---------- */
.ph {
  display: block; aspect-ratio: 16 / 10;
  border: 1px solid var(--line); border-radius: var(--r-sm);
  background: linear-gradient(135deg, var(--ph-a), var(--ph-b));
  position: relative;
}

/* ---------- 入场动画 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity var(--dur-3) var(--ease), transform var(--dur-3) var(--ease);
  transition-delay: var(--reveal-delay, 0ms);
  will-change: opacity, transform;
}
[data-reveal].is-in { opacity: 1; transform: translateY(0); }

/* Staggered reveal animation for lists */
[data-reveal-stagger] > * {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity var(--dur-2) var(--ease), transform var(--dur-2) var(--ease);
}
[data-reveal-stagger].is-in > *:nth-child(1) { transition-delay: 50ms; }
[data-reveal-stagger].is-in > *:nth-child(2) { transition-delay: 100ms; }
[data-reveal-stagger].is-in > *:nth-child(3) { transition-delay: 150ms; }
[data-reveal-stagger].is-in > *:nth-child(4) { transition-delay: 200ms; }
[data-reveal-stagger].is-in > *:nth-child(5) { transition-delay: 250ms; }
[data-reveal-stagger].is-in > *:nth-child(n+6) { transition-delay: 300ms; }
[data-reveal-stagger].is-in > * { opacity: 1; transform: translateY(0); }

/* Pulse animation for interactive elements */
@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}

/* Shimmer effect for loading states */
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

.shimmer {
  background: linear-gradient(
    90deg,
    var(--paper-2) 0%,
    var(--paper-3) 50%,
    var(--paper-2) 100%
  );
  background-size: 200% 100%;
  animation: shimmer 2s ease-in-out infinite;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
  [data-reveal] { opacity: 1 !important; transform: none !important; }
}