/* ===========================================================
   排版系统：瑞士国际主义网格 + 日式余白
   — 严格左对齐与统一左边距（秩序感）
   — 字号对比拉开：超大主题 vs 极小眉标（层级）
   — 用留白分隔，弱化边框与阴影（余白）
   — 字距疏朗、行高宽松（呼吸感）
   =========================================================== */

:root {
  --bg: #FAF6EF;          /* 暖米底 */
  --card: #FFFFFF;
  --ink: #17181A;         /* 近墨黑 */
  --muted: #8B9096;       /* 中间灰 */
  --faint: #B4B9BE;       /* 眉标灰 */
  --blue: #1A73E8;
  --red: #D93025;
  --yellow: #C9A227;      /* 沉稳芥末黄 */
  --gray: #9AA0A6;
  --hairline: rgba(23, 24, 26, 0.10);
  --border: 1px solid var(--hairline);
  --pad: 22px;            /* 统一左边距 / 网格基线 */
  --radius: 10px;
}

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

body {
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 24px 16px 64px;
}

.app {
  width: 100%;
  max-width: 420px;
  background: var(--bg);
  border-radius: 20px;
  border: var(--border);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.03);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  min-height: 660px;
}

/* ---------- 顶栏（只在测字中出现，尽量安静） ---------- */
.topbar {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 20px var(--pad) 4px;
}

.topbar .title {
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.22em;
  color: var(--faint);
}

.topbar .meta {
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--faint);
  min-height: 0;
}

.undo-btn {
  border: none;
  background: transparent;
  color: var(--faint);
  font-size: 11px;
  letter-spacing: 0.16em;
  cursor: pointer;
  padding: 0;
  transition: color .15s ease;
}

.undo-btn:hover { color: var(--blue); }
.undo-btn:disabled { opacity: .3; cursor: default; }

/* ---------- 主区 ---------- */
.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 8px var(--pad) 20px;
}

/* 眉标：极小、大字距，建立层级 */
.kicker {
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.34em;
  color: var(--faint);
  text-indent: 0.34em; /* 补偿末字字距，保证左端严格对齐 */
}

/* 秩序线：短细线，不喧宾夺主 */
.rule {
  width: 32px;
  height: 1.5px;
  background: var(--ink);
  opacity: .78;
}

.big-char {
  font-family: "LXGW WenKai GB Medium", "Kaiti SC", serif;
  font-size: 168px;
  line-height: 1.05;
  color: #141414;
  letter-spacing: 0.02em;
  user-select: none;
  margin-top: 20px;
}

/* 词组页：字缩小，给词组让出版面 */
.big-char.sm { font-size: 92px; color: #3C4043; }

.hint {
  font-size: 11.5px;
  letter-spacing: 0.18em;
  color: var(--faint);
  text-indent: 0.18em;
  margin-top: 24px;
}

/* ---------- 词组页 ---------- */
/* 词组页：无边框、无卡片，2×2 居中排列，让词本身成为内容 */
.word-panel {
  margin: 34px auto 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  column-gap: 40px;
  row-gap: 28px;
  justify-items: center;
  width: 100%;
  max-width: 330px;
}

.word-item {
  font-family: "LXGW WenKai GB Medium", "Kaiti SC", serif;
  font-size: 27px;
  font-weight: 400;
  letter-spacing: 0.06em;
  color: var(--ink);
  text-align: center;
  line-height: 1.2;
}

.word-item .target { color: var(--blue); }

/* ---------- 按钮 ---------- */
.btn-row {
  display: flex;
  justify-content: center;
  gap: 10px;
  padding: 0 var(--pad) 14px;
}

.btn {
  min-width: 78px;
  height: 36px;
  padding: 0 16px;
  border: none;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 400;
  letter-spacing: 0.1em;
  color: #fff;
  cursor: pointer;
  transition: transform .12s ease, opacity .12s ease;
}

.btn:active { transform: scale(.96); }

.btn.correct { background: var(--blue); }
.btn.wrong { background: var(--red); }
.btn.skip { background: var(--gray); }
.btn.next { background: var(--yellow); color: #fff; }

/* ---------- 首页 ---------- */
.start-screen {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  justify-content: center;
  flex: 1;
  width: 100%;
  padding: 30px var(--pad) 26px;
  text-align: left;
}

.start-title {
  font-family: "LXGW WenKai GB Medium", "Kaiti SC", serif;
  font-size: 33px;
  font-weight: 700;
  letter-spacing: 0.06em;
  line-height: 1.2;
  color: #141414;
  margin-top: 12px;
  text-indent: -0.02em;
}

.start-rule { margin: 20px 0 18px; }

.start-sub {
  font-size: 12.5px;
  color: var(--muted);
  line-height: 2.1;
  letter-spacing: 0.11em;
  white-space: pre-line;
}

.primary-btn {
  align-self: flex-start;
  height: 44px;
  margin-top: 34px;
  padding: 0 24px;
  border: none;
  border-radius: 999px;
  background: var(--blue);
  color: #fff;
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-indent: 0.08em;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(26, 115, 232, 0.14);
  transition: transform .14s ease, box-shadow .14s ease;
}

.primary-btn:active {
  transform: scale(.97);
  box-shadow: 0 1px 4px rgba(26, 115, 232, 0.12);
}

/* 数字区：白卡片 + 细字重大数字 + 极小标签 */
.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  width: 100%;
  margin-top: 38px;
}

.stat-card {
  background: var(--card);
  border: var(--border);
  border-radius: var(--radius);
  padding: 24px 6px 18px;
  text-align: center;
}

.stat-card .num {
  font-size: 32px;
  font-weight: 300;
  letter-spacing: -0.01em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  line-height: 1;
}

.stat-card .label {
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-indent: 0.18em;
  color: var(--faint);
  margin-top: 12px;
}

/* ---------- 结果页 ---------- */
.result-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  flex: 1;
  width: 100%;
  gap: 14px;
  padding: 28px var(--pad);
  text-align: center;
}

.result-screen .start-title {
  font-family: inherit;
  font-size: 20px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-indent: 0.12em;
  margin-top: 0;
}

.result-list {
  width: 100%;
  max-height: 240px;
  overflow-y: auto;
  background: var(--card);
  border: var(--border);
  border-radius: var(--radius);
  padding: 6px 14px;
}

.result-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 11px 2px;
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.result-row:last-child { border-bottom: none; }
.result-row .char { font-size: 17px; font-weight: 400; letter-spacing: 0.06em; }
.result-row .status { font-size: 11px; letter-spacing: 0.12em; }
.result-row .status.ok { color: var(--blue); }
.result-row .status.no { color: var(--red); }
.result-row .status.skip { color: var(--faint); }

.result-screen .primary-btn { align-self: center; margin-top: 6px; }

/* ---------- 家长工具 ---------- */
.settings {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 4px var(--pad) 20px;
}

.settings-title {
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.22em;
  color: var(--faint);
  margin-bottom: 4px;
}

.small-btn {
  height: 34px;
  padding: 0 14px;
  border-radius: 999px;
  background: #fff;
  border: var(--border);
  color: var(--muted);
  font-size: 12px;
  letter-spacing: 0.08em;
  cursor: pointer;
}

.small-btn:hover { border-color: var(--blue); color: var(--blue); }

.sync-line {
  font-size: 11.5px;
  line-height: 1.8;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin-bottom: 2px;
}

.supplement-row { display: flex; gap: 8px; align-items: center; }

.supplement-input {
  flex: 1;
  height: 34px;
  border-radius: var(--radius);
  border: var(--border);
  padding: 0 12px;
  font-size: 13px;
  background: #fff;
  color: var(--ink);
  outline: none;
}

.supplement-input:focus { border-color: var(--blue); }

/* 首页底部：家长工具（弱化，下划线黄字，居中） */
.parent-link {
  text-align: center;
  font-size: 11px;
  letter-spacing: 0.2em;
  text-indent: 0.2em;
  color: var(--yellow);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
  cursor: pointer;
  padding: 4px 20px 26px;
  user-select: none;
}

.parent-link:active { opacity: .55; }