/* ============================================================
   单词闪卡 — 样式（Chrome 61 基线层，同系列视觉体系）
   含 CSS 3D 翻转卡（翻牌记忆配对同款方案，-webkit- 前缀）
   约束：无 flex gap / aspect-ratio / clamp / 逻辑属性 / :has
   ============================================================ */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body { height: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
               "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: #f2f3f5;
  color: #1f2329;
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: transparent;
  -webkit-touch-callout: none;
  touch-action: manipulation;
  -webkit-user-select: none;
  user-select: none;
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-flex-direction: column;
  flex-direction: column;
  height: 100vh;
  height: calc(var(--app-height, 100vh));
}

/* ---------- 顶栏 ---------- */
.app-header {
  -webkit-box-flex: 0;
  -webkit-flex: 0 0 auto;
  flex: 0 0 auto;
  position: relative;
  padding-top: var(--safe-area-inset-top, env(safe-area-inset-top, 0px));
  background: #ffffff;
  border-bottom: 1px solid #e5e6eb;
}

.header-brand {
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-box-align: center;
  -webkit-align-items: center;
  align-items: center;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
  justify-content: center;
  padding: 10px 16px;
  min-height: 52px;
}

.header-icon {
  width: 32px;
  height: 32px;
  margin-right: 8px;
  border-radius: 8px;
  -webkit-box-flex: 0;
  -webkit-flex: 0 0 auto;
  flex: 0 0 auto;
}

.header-title { font-size: 17px; font-weight: 600; }

.header-ver {
  margin-left: 6px;
  font-size: 10px;
  color: #c9cdd4;
}

.header-back {
  position: absolute;
  left: 4px;
  top: 0;
  bottom: 0;
  width: 56px;
  border: none;
  background: transparent;
  color: #165dff;
  font-size: 22px;
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-box-align: center;
  -webkit-align-items: center;
  align-items: center;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
  justify-content: center;
}

.header-back:active { opacity: 0.6; }

/* ---------- 主体 ---------- */
.app-main {
  -webkit-box-flex: 1;
  -webkit-flex: 1 1 auto;
  flex: 1 1 auto;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior-y: contain;
  min-width: 0;
}

.view { padding: 12px 16px; max-width: 720px; margin: 0 auto; }

/* 首页垂直分布：整体垂直居中 */
.view.home {
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-flex-direction: column;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
  justify-content: center;
  min-height: 100%;
}

/* ---------- 通用按钮 ---------- */
.btn {
  min-height: 48px;
  border: none;
  border-radius: 10px;
  font-size: 16px;
  color: #165dff;
  background: #eef3ff;
  cursor: pointer;
  -webkit-box-flex: 1;
  -webkit-flex: 1 1 auto;
  flex: 1 1 auto;
}

.btn:active { opacity: 0.7; }
.btn-primary { background: #165dff; color: #ffffff; }

.btn-row {
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  margin-top: 12px;
}

.btn-row > * + * { margin-left: 10px; }

.page-title {
  font-size: 16px;
  font-weight: 600;
  margin: 8px 0 12px;
  text-align: center;
}

/* ---------- 首页：入口 ---------- */
.entry-list { margin-top: 4px; }

.entry-item {
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-box-align: center;
  -webkit-align-items: center;
  align-items: center;
  padding: 18px 16px;
  background: #ffffff;
  border-radius: 14px;
  margin-bottom: 12px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
  cursor: pointer;
}

.entry-item:active { opacity: 0.75; }

.entry-icon {
  font-size: 28px;
  margin-right: 14px;
  -webkit-box-flex: 0;
  -webkit-flex: 0 0 auto;
  flex: 0 0 auto;
}

.entry-text { -webkit-box-flex: 1; -webkit-flex: 1 1 auto; flex: 1 1 auto; min-width: 0; }

.entry-name { font-size: 17px; font-weight: 600; }

.entry-desc { font-size: 12px; color: #8a919f; margin-top: 3px; }

.entry-arrow { font-size: 18px; color: #c9cdd4; -webkit-box-flex: 0; -webkit-flex: 0 0 auto; flex: 0 0 auto; }

.home-progress {
  background: #ffffff;
  border-radius: 14px;
  padding: 14px 16px;
  margin-bottom: 14px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
  font-size: 13px;
  color: #4e5969;
  line-height: 1.8;
}

.home-progress b { color: #ff9c1a; }

/* ---------- 列表类（选册/选单元） ---------- */
.point-list { margin-top: 4px; }

.point-item {
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-box-align: center;
  -webkit-align-items: center;
  align-items: center;
  -webkit-box-pack: justify;
  -webkit-justify-content: space-between;
  justify-content: space-between;
  padding: 14px 16px;
  background: #ffffff;
  border-radius: 10px;
  margin-bottom: 8px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.06);
}

.point-name { font-size: 15px; font-weight: 600; }

.point-meta { font-size: 12px; color: #8a919f; margin-top: 3px; }

/* ---------- 练习页 ---------- */
.quiz-top {
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-box-pack: justify;
  -webkit-justify-content: space-between;
  justify-content: space-between;
  -webkit-box-align: center;
  -webkit-align-items: center;
  align-items: center;
  margin-bottom: 10px;
}

.quiz-progress { font-size: 14px; color: #4e5969; }

/* ---------- CSS 3D 翻转卡 ---------- */
.flip-scene {
  position: relative;
  -webkit-perspective: 900px;
  perspective: 900px;
  min-height: 300px;
  cursor: pointer;
}

.flip-inner {
  position: relative;
  width: 100%;
  min-height: 300px;
  -webkit-transform-style: preserve-3d;
  transform-style: preserve-3d;
  -webkit-transition: -webkit-transform 0.45s;
  transition: transform 0.45s;
}

.flip-inner.flipped {
  -webkit-transform: rotateY(180deg);
  transform: rotateY(180deg);
}

.flip-face {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  min-height: 300px;
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-flex-direction: column;
  flex-direction: column;
  -webkit-box-align: center;
  -webkit-align-items: center;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
  justify-content: center;
  padding: 20px;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
}

.flip-front { z-index: 2; }

.flip-back {
  -webkit-transform: rotateY(180deg);
  transform: rotateY(180deg);
  background: #eef3ff;
}

.card-word {
  font-size: 44px;
  font-weight: 800;
  color: #1f2329;
  text-align: center;
  word-break: break-all;
  line-height: 1.3;
}

.card-cn {
  font-size: 30px;
  font-weight: 700;
  color: #165dff;
  text-align: center;
}

.card-tip {
  margin-top: 18px;
  font-size: 13px;
  color: #8a919f;
}

/* 认识 / 不认识 */
.judge-row {
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  margin-top: 14px;
}

.judge-row > * + * { margin-left: 10px; }

.judge-known { background: #00a854; }
.judge-unknown { background: #ff9c1a; color: #ffffff; }

/* 反馈 */
.quiz-feedback {
  min-height: 36px;
  margin-top: 10px;
  font-size: 16px;
  font-weight: 600;
  text-align: center;
}

.quiz-feedback.ok { color: #00a854; }
.quiz-feedback.bad { color: #f5222d; }
.quiz-feedback.hint { color: #ff9c1a; }

/* ---------- 结果页 ---------- */
.result-card {
  background: #ffffff;
  border-radius: 14px;
  padding: 24px;
  text-align: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  margin-bottom: 16px;
}

.result-score { font-size: 42px; font-weight: 800; color: #165dff; }

.result-stars { font-size: 22px; color: #f5a623; margin-top: 6px; min-height: 26px; }

.result-stats {
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
  justify-content: center;
  margin-top: 12px;
}

.result-stat {
  margin: 0 14px;
  font-size: 14px;
  color: #4e5969;
  text-align: center;
}

.result-stat b { display: block; font-size: 20px; color: #1f2329; }

/* 学习说明 */
.learn-explain {
  font-size: 14px;
  line-height: 1.8;
  color: #4e5969;
  white-space: pre-line;
  background: #f7f8fa;
  border-radius: 10px;
  padding: 12px;
  margin-top: 12px;
}

/* ---------- 底栏 ---------- */
.app-footer {
  -webkit-box-flex: 0;
  -webkit-flex: 0 0 auto;
  flex: 0 0 auto;
  background: #ffffff;
  border-top: 1px solid #e5e6eb;
  padding-bottom: var(--safe-area-inset-bottom, env(safe-area-inset-bottom, 0px));
}

.footer-nav {
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
  justify-content: center;
  padding: 8px 12px 10px;
}

.footer-nav > * + * { margin-left: 10px; }

.footer-btn {
  min-width: 64px;
  padding: 9px 0;
  font-size: 13px;
  color: #165dff;
  text-align: center;
  border-radius: 8px;
  background: #f2f3f5;
}

/* ---------- 打卡日历 ---------- */
.calendar {
  background: #ffffff;
  border-radius: 14px;
  padding: 16px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.calendar-grid {
  display: -webkit-box;
  display: -webkit-flex;
  display: flex;
  -webkit-flex-wrap: wrap;
  flex-wrap: wrap;
  margin-top: 8px;
}

.calendar-grid > * { width: 14.28%; padding: 4px; }

.cal-day {
  width: 100%;
  padding: 8px 0;
  text-align: center;
  font-size: 13px;
  border-radius: 6px;
  color: #8a919f;
  background: #f7f8fa;
}

.cal-day.done { background: #ff9c1a; color: #ffffff; font-weight: 700; }

.cal-day.today { outline: 2px solid #165dff; }

.streak-info { text-align: center; margin-top: 10px; font-size: 14px; color: #4e5969; }
.streak-info b { color: #ff9c1a; }

/* 安全区增强 */
@supports ((padding-bottom: var(--safe-area-inset-bottom)) or (padding-bottom: env(safe-area-inset-bottom))) {
  .app-header { padding-top: var(--safe-area-inset-top, env(safe-area-inset-top, 0px)); }
  .app-footer { padding-bottom: var(--safe-area-inset-bottom, env(safe-area-inset-bottom, 0px)); }
}