/* ==========================================================================
   石青 SHIQING — Base
   reset + 排版基线 + 焦点 + 版面容器
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  /* 根部橡皮筋回弹会让吸顶玻璃反复重建背景，表现为到顶时"抽一下" */
  overscroll-behavior-y: none;
}

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

body {
  margin: 0;
  background: var(--c-paper);
  color: var(--c-ink);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  font-synthesis-weight: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

/* 环境氛围光：预模糊径向渐变，只动 transform，开销低 */
body::before {
  content: "";
  position: fixed;
  inset: -18% -12%;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(42% 30% at 14% 8%,  var(--blob-1), transparent 66%),
    radial-gradient(34% 26% at 88% 4%,  var(--blob-3), transparent 62%),
    radial-gradient(46% 34% at 82% 78%, var(--blob-2), transparent 64%),
    radial-gradient(30% 24% at 6% 82%,  var(--blob-3), transparent 60%);
  animation: ambient-drift 36s var(--ease-in-out) infinite alternate;
}

@keyframes ambient-drift {
  from { transform: translate3d(-2.5%, -1.5%, 0) scale(1); }
  to   { transform: translate3d(2.5%, 1.5%, 0) scale(1.04); }
}

/* 页面入场：幅度小、时间长，像镜头轻轻推近而不是"弹出来" */
@media (prefers-reduced-motion: no-preference) {
  .js body { animation: page-in var(--dur-hero) var(--ease-silk) both; }
}

@keyframes page-in {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: none; }
}

/* 减少动画：位移、缩放、模糊全部收敛到近乎瞬时；
   保留 opacity 的变化，因为它是状态可见性的一部分，不是装饰 */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 1ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 1ms !important;
    scroll-behavior: auto !important;
  }
}

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

img { height: auto; }

/* 作者样式里的 display 会盖掉 UA 的 [hidden]，这里统一兜住 */
[hidden] { display: none !important; }

/* ---- Headings ----
   标题统一用 display 字体；display 字体在小字号下会显瘦，所以下限锁在 h3 以上 */
h1, h2, h3, h4 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 400;
  line-height: var(--lh-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--c-ink);
  text-wrap: balance;
}

h1 { font-size: var(--fs-h1); }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); font-family: var(--font-body); font-weight: 500; letter-spacing: 0; }
h4 { font-size: var(--fs-body); font-family: var(--font-body); font-weight: 600; letter-spacing: 0; }

p {
  margin: 0 0 var(--sp-4);
  text-wrap: pretty;   /* 减少孤字；浏览器不支持时无副作用 */
}

p:last-child { margin-bottom: 0; }

a {
  color: inherit;
  text-decoration-color: color-mix(in srgb, currentColor 32%, transparent);
  text-underline-offset: 0.22em;
  transition: color var(--dur-fast) var(--ease-out),
              text-decoration-color var(--dur-fast) var(--ease-out);
}

a:hover { text-decoration-color: currentColor; }

ul, ol { margin: 0; padding: 0; }

li { list-style: none; }

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
  margin: 0;
}

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

/* 锚点跳转时给吸顶导航留出空间 */
[id] { scroll-margin-top: calc(var(--header-h) + var(--sp-4)); }

/* ---- Focus ----
   保留原生焦点环的可见性；只在支持 :focus-visible 的浏览器里收紧外观，
   不做「去掉 outline 再加一个几乎看不见的环」这种自欺写法 */
:focus-visible {
  outline: 2px solid var(--c-focus);
  outline-offset: 2px;
  border-radius: var(--r-inner);
}

::selection {
  background: var(--c-accent);
  color: var(--c-paper);
}

/* ---- Layout ---- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.container--narrow {
  max-width: var(--container-narrow);
}

.section {
  padding-block: var(--section-y);
}

.section--sunk {
  background: var(--c-paper-sunk);
}

.section--tight {
  padding-block: clamp(40px, 5vw, 72px);
}

.section-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--sp-5);
  margin-bottom: var(--sp-6);
  flex-wrap: wrap;
}

.section-head__text { max-width: 46ch; }

.section-head p {
  margin: var(--sp-2) 0 0;
  color: var(--c-muted);
  font-size: var(--fs-sm);
}

/* ---- Type utilities ---- */
.eyebrow {
  display: block;
  font-family: var(--font-body);
  font-size: var(--fs-micro);
  font-weight: 600;
  letter-spacing: var(--tracking-micro);
  text-transform: uppercase;
  color: var(--c-muted);
}

.lead {
  font-size: var(--fs-lead);
  line-height: 1.6;
  color: var(--c-ink-soft);
  text-wrap: pretty;
}

.muted { color: var(--c-muted); }

.num {
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
}

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

.skip-link {
  position: absolute;
  top: var(--sp-2);
  left: var(--sp-2);
  z-index: 200;
  padding: var(--sp-3) var(--sp-4);
  background: var(--c-ink);
  color: var(--c-paper);
  border-radius: var(--r-inner);
  transform: translateY(-200%);
  transition: transform var(--dur-fast) var(--ease-out);
}

.skip-link:focus-visible { transform: translateY(0); }

/* ---- Reveal on scroll ----
   只在 JS 标记了 .js 时才隐藏初态，避免脚本失败导致内容永久不可见；
   reduced-motion 下直接显示 */
.js .reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity var(--dur-slow) var(--ease-out),
              transform var(--dur-slow) var(--ease-out);
  transition-delay: var(--reveal-delay, 0ms);
}

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

@media (prefers-reduced-motion: reduce) {
  .js .reveal {
    opacity: 1;
    transform: none;
  }
}

/* ---- Film grain ----
   颗粒是陶瓷摄影的一部分，用在釉面视觉与深色区块上；
   纯色区块不加，否则整页会显得脏 */
.grain { position: relative; }

.grain::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  border-radius: inherit;
  opacity: 0.5;
  mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='g'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.82' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='160' height='160' filter='url(%23g)' opacity='0.42'/%3E%3C/svg%3E");
}

/* ---- 共享关键帧 ---- */

/* 内容切换：淡入 + 轻微上浮 */
@keyframes fade-slide-in {
  from { opacity: 0; transform: translateY(12px) scale(0.985); }
  to   { opacity: 1; transform: none; }
}

/* 数字/徽标变化时的确认感 */
@keyframes pop-in {
  0%   { transform: scale(0.86); opacity: 0.4; }
  60%  { transform: scale(1.06); opacity: 1; }
  100% { transform: scale(1); }
}

/* 按钮高光扫过：只动 background-position */
@keyframes sheen-sweep {
  from { background-position: -160% 0; }
  to   { background-position: 240% 0; }
}

/* 悬浮微漂：仅装饰元素 */
@keyframes float-y {
  from { transform: translateY(-4px); }
  to   { transform: translateY(4px); }
}

/* 照片揭示：比文字稍慢，先放大后归位（不做 blur，避免整层重绘） */
@keyframes media-reveal {
  from { opacity: 0; transform: scale(1.035); }
  to   { opacity: 1; transform: none; }
}

/* 涟漪点：transform 缩放，低耗 */
@keyframes ripple {
  from { transform: scale(0); opacity: 0.42; }
  to   { transform: scale(1); opacity: 0; }
}

.ripple-dot {
  position: absolute;
  border-radius: 50%;
  background: currentColor;
  pointer-events: none;
  animation: ripple 720ms var(--ease-out) forwards;
}

/* 内容进入列表时的入场类（由 JS 加/移除） */
.entering { animation: fade-slide-in var(--dur-pop) var(--ease-silk) both; }

/* 照片统一入场 */
.photo {
  animation: media-reveal var(--dur-slow) var(--ease-out) both;
  /* 素材来源不同，统一压一档饱和与对比，避免整页色调忽冷忽暖 */
  filter: saturate(0.94) contrast(1.02);
}

@media (prefers-reduced-motion: reduce) {
  body::before { animation: none; }
  .js body { animation: none; }
  .ripple-dot { display: none; }
  .entering, .photo { animation: none; }
}