/* ============================================================
   system.css — iOS 原生设计系统（设计 token / 基础组件）
   拍立得模拟器 · 阶段三 Round 1
   ============================================================ */

:root {
  /* 配色：iOS 系统灰 + 系统蓝强调 */
  --bg:           #F2F2F7;   /* systemGroupedBackground */
  --bg-elevated:  #FFFFFF;   /* 卡片 / 导航毛玻璃底 */
  --card:         #FFFFFF;
  --sep:          rgba(60, 60, 67, 0.29);   /* hairline separator */
  --label:        #1C1C1E;
  --label-2:      #8E8E93;   /* secondary label */
  --label-3:      #C7C7CC;
  --accent:       #007AFF;   /* systemBlue */
  --accent-press: #0062CC;
  --green:        #34C759;
  --radius:       14px;
  --radius-lg:    20px;

  /* 尺寸 */
  --sb-h:   44px;   /* 状态栏 */
  --nav-h:  44px;   /* 导航栏 */
  --ease:   cubic-bezier(.32, .72, 0, 1);   /* iOS 推送缓动 */
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display",
          "PingFang SC", "Helvetica Neue", Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

html, body { margin: 0; height: 100%; }

body {
  font-family: var(--font);
  color: var(--label);
  background: #D1D1D6;            /* 桌面端设备外底色 */
  display: flex;
  justify-content: center;
  align-items: center;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

#app {
  position: relative;
  width: 100%;
  max-width: 430px;
  height: 100dvh;
  background: var(--bg);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* 桌面端模拟设备外壳 */
@media (min-width: 480px) {
  body { padding: 24px 0; }
  #app {
    height: min(880px, 92vh);
    border-radius: 46px;
    border: 11px solid #1c1c1e;
    box-shadow: 0 40px 90px -24px rgba(0, 0, 0, .5);
  }
}

/* —— 屏幕容器与转场 —— */
.stage { position: relative; flex: 1; overflow: hidden; }

.screen {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  transform: translate3d(100%, 0, 0);
  visibility: hidden;
  transition: transform .44s var(--ease), visibility .44s var(--ease);
  will-change: transform;
  backface-visibility: hidden;
}
.screen.active { transform: translate3d(0, 0, 0); visibility: visible; }
.screen.from-right { transform: translate3d(100%, 0, 0); }

.screen-inner { flex: 1; display: flex; flex-direction: column; min-height: 0; }

/* —— 导航栏（毛玻璃） —— */
.navbar {
  flex: none;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  padding: 0 6px;
  position: relative;
  background: rgba(249, 249, 249, .82);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: .5px solid var(--sep);
  z-index: 10;
}
.nav-back {
  width: 44px; height: 44px; border: 0; background: none;
  color: var(--accent); display: grid; place-items: center; cursor: pointer;
  flex: none; transition: opacity .15s, transform .15s;
}
.nav-back svg { width: 24px; height: 24px; }
.nav-back:active { opacity: .45; }
.nav-title {
  position: absolute; left: 50%; transform: translateX(-50%);
  font-size: 17px; font-weight: 600; color: var(--label);
  pointer-events: none;
}
.nav-right { width: 44px; flex: none; }
@media (prefers-color-scheme: dark) {
  .navbar { background: rgba(30, 30, 32, .82); border-bottom-color: rgba(255,255,255,.16); }
}

/* —— 分段控件（UISegmentedControl） —— */
.segmented {
  display: flex;
  background: #E4E4EA;
  border-radius: 9px;
  padding: 2px;
  position: relative;
}
.segmented button {
  flex: 1;
  border: 0; background: none;
  font-size: 14px; font-weight: 600; color: var(--label);
  padding: 7px 0; border-radius: 7px; cursor: pointer;
  position: relative; z-index: 1;
  transition: color .2s;
}
.segmented button.sel { color: var(--label); }
.segmented::before {
  content: ""; position: absolute; top: 2px; bottom: 2px; left: 2px;
  width: calc((100% - 4px) / 3);
  background: #fff; border-radius: 7px;
  box-shadow: 0 3px 8px rgba(0,0,0,.12), 0 1px 2px rgba(0,0,0,.08);
  transform: translateX(calc(var(--seg, 0) * 100%));
  transition: transform .28s var(--ease);
  z-index: 0;
}
.segmented button.sel { color: #000; }

/* —— 主按钮 —— */
.btn-primary {
  width: 100%;
  border: 0;
  background: var(--accent);
  color: #fff;
  font-size: 17px; font-weight: 600;
  padding: 14px 0;
  border-radius: 14px;
  cursor: pointer;
  transition: background .15s, transform .1s;
}
.btn-primary:active { background: var(--accent-press); transform: scale(.985); }

.tabbar-safe {
  flex: none;
  padding: 12px 16px calc(16px + env(safe-area-inset-bottom, 0px));
  background: var(--bg);
  border-top: .5px solid var(--sep);
}

/* —— 浮动 + 按钮 —— */
.fab {
  position: absolute;
  left: 50%; bottom: calc(40px + env(safe-area-inset-bottom, 0px));
  transform: translateX(-50%);
  width: 64px; height: 64px; border-radius: 50%;
  border: 0; background: var(--accent); color: #fff;
  display: grid; place-items: center;
  box-shadow: 0 12px 28px -6px rgba(0,122,255,.6), 0 4px 10px rgba(0,0,0,.18);
  cursor: pointer;
  transition: transform .18s var(--ease), background .15s;
  z-index: 5;
}
.fab svg { width: 30px; height: 30px; transition: transform .3s var(--ease); }
.fab:active { background: var(--accent-press); transform: translateX(-50%) scale(.92); }
.fab:active svg { transform: rotate(90deg); }

/* —— 相纸缩略（真实 instax 比例） —— */
.paper-thumb {
  position: relative;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 10px 26px -10px rgba(0,0,0,.35), 0 3px 8px rgba(0,0,0,.12);
  overflow: hidden;
}
.paper-thumb .pt-image {
  position: absolute;
  background: linear-gradient(155deg, #F2B07C, #D9694E 55%, #B14B8E);
}
.paper-thumb .pt-caption {
  position: absolute; left: 0; right: 0; bottom: 0;
  text-align: center; color: var(--label-2);
  font: 600 10px/1 ui-monospace, "SF Mono", monospace;
  letter-spacing: .12em; padding-bottom: 7px;
}
.paper-thumb.mini  { aspect-ratio: 54 / 86; }
.paper-thumb.sq    { aspect-ratio: 72 / 86; }
.paper-thumb.wide  { aspect-ratio: 108 / 86; }
.paper-thumb.mini .pt-image  { left: 4.6%; top: 2.3%; right: 4.6%; bottom: 25.6%; }
.paper-thumb.sq   .pt-image  { left: 6.9%; top: 5.8%; right: 6.9%; bottom: 22.1%; }
.paper-thumb.wide .pt-image  { left: 4.2%; top: 2.3%; right: 4.2%; bottom: 25.6%; }

/* 选相纸卡片里的相纸缩略 */
.tc-paper {
  display: block;
  background: #fff;
  border-radius: 6px;
  position: relative;
  box-shadow: inset 0 0 0 .5px var(--sep), 0 2px 6px rgba(0,0,0,.12);
}
.tc-paper::before {
  content: ""; position: absolute;
  background: linear-gradient(155deg, #F2B07C, #D9694E 55%, #B14B8E);
  border-radius: 1px;
}
.tc-paper.mini  { width: 30px; aspect-ratio: 54 / 86; }
.tc-paper.sq    { width: 38px; aspect-ratio: 72 / 86; }
.tc-paper.wide  { width: 46px; aspect-ratio: 108 / 86; }
.tc-paper.mini::before  { left: 9%; top: 7%; right: 9%; bottom: 26%; }
.tc-paper.sq::before    { left: 13%; top: 12%; right: 13%; bottom: 22%; }
.tc-paper.wide::before  { left: 7%; top: 10%; right: 7%; bottom: 26%; }

/* 文件选择框：视觉隐藏但保留可点击（不用 display:none 以免程序化 click 被拦截） */
.file-hidden { position: absolute; width: 1px; height: 1px; opacity: 0; pointer-events: none; }

/* 轻量提示 toast */
.toast {
  position: fixed; left: 50%; bottom: 84px; transform: translateX(-50%) translateY(10px);
  background: rgba(30,30,34,.92); color: #fff; font-size: 13.5px; font-weight: 500;
  padding: 10px 18px; border-radius: 22px; z-index: 9999; opacity: 0;
  transition: opacity .26s var(--ease), transform .26s var(--ease);
  pointer-events: none; -webkit-backdrop-filter: blur(8px); backdrop-filter: blur(8px);
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }