/* ============================================================
   基础：重置、字体、app 外壳（封面层 / app 层 / 弹层）
   只引用 tokens.css 的变量。
   ============================================================ */

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  margin: 0;
  overflow: hidden;
  background: var(--app-bg);
  color: var(--ink);
  font-family: var(--font-ui);
  font-size: var(--fs-body);
  letter-spacing: var(--tracking);
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: transparent;
  text-size-adjust: 100%;
}

button {
  color: inherit;
  font: inherit;
  letter-spacing: inherit;
}

a {
  color: inherit;
  text-decoration: none;
}

h1,
h2,
p,
ol,
dl,
dd,
figure {
  margin: 0;
  padding: 0;
}

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

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.icon {
  width: 22px;
  height: 22px;
  flex: none;
}

.icon-sm {
  width: 16px;
  height: 16px;
}

/* iPhone 主屏 app 里页面比整屏矮一截，底部会露出 html 底色；进 app 后让它和标签栏同色，看起来是一条整栏 */
@media (max-width: 899px) {
  html[data-edition],
  html[data-edition] body {
    background: var(--tabbar-bg);
  }
}

/* ---------- 外壳：封面层和 app 层叠在一起，切换时淡入淡出 ---------- */

.app {
  position: fixed;
  inset: 0;
  overflow: hidden;
}

.landing,
.shell {
  position: absolute;
  inset: 0;
  transition:
    opacity var(--dur-slow) var(--ease),
    transform var(--dur-slow) var(--ease),
    visibility 0s linear 0s;
}

.shell {
  display: flex;
  flex-direction: column;
  background: var(--app-bg);
  opacity: 0;
  visibility: hidden;
  transform: translateX(4%);
  pointer-events: none;
}

.app.is-app .shell {
  opacity: 1;
  visibility: visible;
  transform: none;
  pointer-events: auto;
}

.app.is-app .landing {
  opacity: 0;
  transform: translateX(-3%);
  pointer-events: none;
  visibility: hidden;
  transition:
    opacity var(--dur-slow) var(--ease),
    transform var(--dur-slow) var(--ease),
    visibility 0s linear var(--dur-slow);
}

/* 页面滚动区：顶栏和标签栏固定，中间滚动 */
.screen {
  flex: 1;
  min-height: 0;
  overflow-x: hidden;
  overflow-y: auto;
  overscroll-behavior: contain;
  -webkit-overflow-scrolling: touch;
}

.screen.is-entering {
  animation: screen-in var(--dur) var(--ease);
}

@keyframes screen-in {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
}

/* 单场页左右滑换场：新的一场从滑动方向进来 */
.screen.is-entering-next {
  animation: screen-in-next var(--dur) var(--ease);
}

.screen.is-entering-prev {
  animation: screen-in-prev var(--dur) var(--ease);
}

@keyframes screen-in-next {
  from {
    opacity: 0;
    transform: translateX(28%);
  }
}

@keyframes screen-in-prev {
  from {
    opacity: 0;
    transform: translateX(-28%);
  }
}

@media (prefers-reduced-motion: reduce) {
  .screen.is-entering,
  .screen.is-entering-next,
  .screen.is-entering-prev {
    animation: none;
  }
}

/* ---------- 横屏 / 大屏：左侧导航 + 顶栏 + 内容 ---------- */
@media (min-width: 900px) {
  .shell {
    display: grid;
    grid-template-columns: var(--rail-w) minmax(0, 1fr);
    grid-template-rows: auto minmax(0, 1fr);
    grid-template-areas:
      "rail appbar"
      "rail screen";
  }

  #appbar {
    grid-area: appbar;
  }

  #screen {
    grid-area: screen;
  }

  #tabbar {
    grid-area: rail;
    min-height: 0;
  }
}