/* 玄学基础知识测试 */

:root {
  --ink: #1a1a1a;
  --paper: #f5f0e6;
  --paper-dark: #e8e0d0;
  --accent: #8b2500;
  --accent-light: #c44a1a;
  --correct: #2d5a27;
  --wrong: #8b2500;
  --border: #c4b8a4;
  --shadow: rgba(26,26,26,.08);
  --gold: #b8860b;
  --font-serif: 'Noto Serif SC','Songti SC',serif;
  --font-display: 'ZCOOL XiaoWei','Kaiti SC',serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-serif);
  font-size: 16px;
  color: var(--ink);
  background: var(--paper);
  background-image:
    radial-gradient(ellipse at 20% 20%, rgba(139,37,0,.03) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 80%, rgba(139,37,0,.02) 0%, transparent 50%);
}

.app {
  max-width: 560px;
  margin: 0 auto;
  padding: 0 1.5rem;
  min-height: 100vh;
  position: relative;
}

/* ══════════════════════════════════════
   通用 Screen
══════════════════════════════════════ */
.screen {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  padding: 2rem 0;
}
.hidden { display: none !important; }

/* ══════════════════════════════════════
   用户顶部栏（登录后所有屏幕顶部）
══════════════════════════════════════ */
.user-top-bar {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 0.5rem;
  padding: 0.6rem 0 0;
}
.user-info-mini { display: flex; align-items: center; gap: 0.35rem; font-size: 0.8rem; color: var(--border); }
.topbar-nick { max-width: 80px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.topbar-level { color: var(--accent); font-weight: 700; font-size: 0.75rem; }
.btn-icon-user {
  width: 34px; height: 34px;
  border: 1.5px solid var(--border);
  border-radius: 50%;
  background: #fff;
  font-family: var(--font-display);
  font-size: 0.9rem;
  color: var(--accent);
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: border-color .2s;
}
.btn-icon-user:hover { border-color: var(--accent); }

/* ══════════════════════════════════════
   登录屏
══════════════════════════════════════ */
.login-wrap {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
}
.login-title { margin: 0; }
.login-card {
  width: 100%;
  max-width: 320px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.75rem;
  box-shadow: 0 4px 20px var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.login-prompt { margin: 0; font-size: 1rem; color: var(--ink); text-align: center; }
.login-input {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  padding: 0.65rem 1rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--paper);
  text-align: center;
}
.login-input:focus { outline: none; border-color: var(--accent); }
.login-error { margin: 0; font-size: 0.85rem; color: var(--wrong); text-align: center; }
.btn-login {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 0.65rem;
  font-family: var(--font-serif);
  font-size: 1rem;
  cursor: pointer;
  min-height: 44px;
  transition: background .2s;
}
.btn-login:hover { background: var(--accent-light); }

/* ══════════════════════════════════════
   Header
══════════════════════════════════════ */
.header { text-align: center; margin-bottom: 2rem; }
.title {
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--ink);
  margin: 0 0 0.3rem;
  letter-spacing: 0.1em;
}
.subtitle { font-size: 0.9rem; color: var(--accent); margin: 0; letter-spacing: 0.2em; }

/* ══════════════════════════════════════
   首页模式卡片
══════════════════════════════════════ */
.mode-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.5rem;
}
.mode-card {
  display: flex; flex-direction: column; align-items: center; gap: 0.5rem;
  background: #fff;
  border: 1.5px solid var(--border);
  border-radius: 10px;
  padding: 2rem 1rem;
  cursor: pointer;
  font-family: var(--font-serif);
  transition: border-color .2s, box-shadow .2s, transform .15s;
  box-shadow: 0 2px 10px var(--shadow);
}
.mode-card:hover {
  border-color: var(--accent);
  box-shadow: 0 6px 24px rgba(139,37,0,.12);
  transform: translateY(-2px);
}
.mode-card:active { transform: scale(.98); }
.mode-card-challenge { grid-column: 1 / -1; flex-direction: row; justify-content: center; gap: 1rem; padding: 1.25rem 1rem; }
.mode-icon { font-family: var(--font-display); font-size: 2.5rem; color: var(--accent); line-height: 1; }
.mode-card-challenge .mode-icon { font-size: 1.8rem; }
.mode-name { font-size: 1.05rem; font-weight: 700; color: var(--ink); letter-spacing: 0.05em; }
.mode-desc { font-size: 0.78rem; color: var(--border); text-align: center; line-height: 1.4; }

/* 排行榜浮动按钮（首页右下） */
.btn-leaderboard {
  position: absolute;
  bottom: 3.5rem;
  right: 0;
  width: 46px; height: 46px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 50%;
  font-family: var(--font-display);
  font-size: 1rem;
  cursor: pointer;
  box-shadow: 0 3px 12px rgba(139,37,0,.25);
  transition: background .2s, transform .15s;
}
.btn-leaderboard:hover { background: var(--accent-light); transform: scale(1.05); }

/* ══════════════════════════════════════
   专项选题
══════════════════════════════════════ */
.screen-nav {
  display: flex; align-items: center; gap: .75rem; margin-bottom: 1.5rem;
}
.screen-nav-title { font-size: 1.05rem; font-weight: 700; letter-spacing: .05em; }
.btn-back {
  background: transparent; border: 1px solid var(--border); border-radius: 6px;
  padding: .35rem .75rem; font-family: var(--font-serif); font-size: .85rem;
  color: var(--ink); cursor: pointer; white-space: nowrap; transition: border-color .2s;
}
.btn-back:hover { border-color: var(--accent); color: var(--accent); }
.cat-tip { font-size: .82rem; color: var(--border); margin: 0 0 1rem; }
.cat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px,1fr)); gap: .6rem; margin-bottom: 1.5rem; }
.cat-chip {
  display: flex; align-items: center; gap: .45rem; padding: .55rem .85rem;
  border: 1.5px solid var(--border); border-radius: 8px; cursor: pointer;
  font-size: .88rem; color: var(--ink); background: #fff;
  transition: border-color .15s, background .15s; user-select: none;
}
.cat-chip input[type="checkbox"] { width: 14px; height: 14px; accent-color: var(--accent); cursor: pointer; flex-shrink: 0; }
.cat-chip.checked { border-color: var(--accent); background: rgba(139,37,0,.07); color: var(--accent); font-weight: 600; }
.cat-actions { display: flex; align-items: center; gap: .75rem; padding-top: .5rem; border-top: 1px solid var(--border); flex-wrap: wrap; }
.btn-toggle-all {
  background: transparent; border: 1px solid var(--border); border-radius: 6px;
  padding: .45rem 1rem; font-family: var(--font-serif); font-size: .85rem;
  color: var(--ink); cursor: pointer; min-height: 40px; transition: border-color .2s;
}
.btn-toggle-all:hover { border-color: var(--accent); }
.cat-count { font-size: .85rem; color: var(--accent); font-weight: 600; flex: 1; text-align: center; }
.btn-start {
  background: var(--accent); color: #fff; border: none; border-radius: 8px;
  padding: .55rem 1.5rem; font-family: var(--font-serif); font-size: .95rem;
  cursor: pointer; min-height: 44px; transition: background .2s, opacity .2s;
}
.btn-start:hover { background: var(--accent-light); }
.btn-start:disabled { opacity: .4; cursor: not-allowed; }

/* ══════════════════════════════════════
   挑战模式选择
══════════════════════════════════════ */
.challenge-mode-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-top: 1rem; }
.challenge-card {
  display: flex; flex-direction: column; align-items: center; gap: .65rem;
  background: #fff; border: 1.5px solid var(--border); border-radius: 10px;
  padding: 1.75rem 1rem; cursor: pointer; font-family: var(--font-serif);
  transition: border-color .2s, box-shadow .2s, transform .15s;
  box-shadow: 0 2px 10px var(--shadow);
}
.challenge-card:hover { border-color: var(--accent); box-shadow: 0 6px 24px rgba(139,37,0,.12); transform: translateY(-2px); }
.challenge-icon { font-size: 2rem; }
.challenge-name { font-size: 1rem; font-weight: 700; color: var(--ink); }
.challenge-desc { font-size: .75rem; color: var(--border); text-align: center; line-height: 1.5; }

/* ══════════════════════════════════════
   计数模式时间选择
══════════════════════════════════════ */
.count-duration-grid { display: flex; gap: 1rem; flex-wrap: wrap; margin-top: 1rem; }
.duration-btn {
  flex: 1; min-width: 120px; display: flex; flex-direction: column; align-items: center; gap: .4rem;
  background: #fff; border: 1.5px solid var(--border); border-radius: 10px;
  padding: 1.5rem 1rem; cursor: pointer; font-family: var(--font-serif);
  transition: border-color .2s, box-shadow .2s, transform .15s;
  box-shadow: 0 2px 10px var(--shadow);
}
.duration-btn:hover { border-color: var(--accent); transform: translateY(-2px); }
.dur-time { font-family: var(--font-display); font-size: 1.3rem; color: var(--accent); font-weight: 700; }
.dur-desc { font-size: .78rem; color: var(--border); }

/* ══════════════════════════════════════
   答题页导航栏
══════════════════════════════════════ */
.quiz-nav {
  display: flex; align-items: center; gap: .6rem; margin-bottom: .75rem;
}
.mode-label { flex: 1; font-size: .8rem; color: var(--border); text-align: center; letter-spacing: .05em; }
.hint-toggle-inline { display: flex; align-items: center; gap: .4rem; }
.hint-toggle-inline .toggle-text { font-size: .8rem; }

/* Toggle */
.toggle-switch { position: relative; display: inline-block; cursor: pointer; }
.toggle-switch input { opacity: 0; width: 0; height: 0; position: absolute; }
.toggle-track {
  display: flex; align-items: center; width: 38px; height: 21px;
  background: var(--border); border-radius: 11px; transition: background .25s; padding: 2px;
}
.toggle-switch input:checked + .toggle-track { background: var(--accent); }
.toggle-thumb {
  width: 17px; height: 17px; background: #fff; border-radius: 50%;
  box-shadow: 0 1px 3px rgba(0,0,0,.2); transition: transform .25s; flex-shrink: 0;
}
.toggle-switch input:checked + .toggle-track .toggle-thumb { transform: translateX(17px); }

/* ══════════════════════════════════════
   挑战模式专属栏
══════════════════════════════════════ */
.challenge-bar {
  display: flex; justify-content: space-between; align-items: center;
  background: var(--ink); color: #fff;
  border-radius: 8px; padding: .5rem 1rem; margin-bottom: .75rem;
  font-family: var(--font-display); font-size: 1rem;
}
.cb-score { font-size: 1rem; }
.cb-score span { font-size: 1.4rem; color: #ffd700; margin-left: .25rem; }
.cb-timer { font-size: 1.1rem; color: #ffd700; }
.cb-timer.danger { color: #ff4444; animation: pulse .5s infinite alternate; }

@keyframes pulse { from { opacity: 1; } to { opacity: .5; } }

/* 单题倒计时进度条（限时模式） */
.q-countdown-wrap {
  position: relative; height: 18px; margin-bottom: .5rem;
  background: var(--paper-dark); border-radius: 9px; overflow: hidden;
}
.q-countdown-bar {
  height: 100%; background: var(--accent);
  border-radius: 9px; transition: width .1s linear, background .3s;
}
.q-countdown-bar.danger { background: #ff4444; }
.q-countdown-text {
  position: absolute; inset: 0; display: flex; align-items: center; justify-content: center;
  font-size: .8rem; font-weight: 700; color: #fff; pointer-events: none;
}

/* ══════════════════════════════════════
   答题卡
══════════════════════════════════════ */
.main { display: flex; flex-direction: column; }
.quiz-card {
  background: #fff; border: 1px solid var(--border); border-radius: 8px;
  padding: 1.75rem; box-shadow: 0 4px 20px var(--shadow);
}
.quiz-meta { display: flex; justify-content: space-between; align-items: center; margin-bottom: 1.5rem; }
.category-tag {
  font-size: .8rem; color: var(--accent); padding: .25rem .6rem;
  border: 1px solid var(--accent); border-radius: 4px; max-width: 65%;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.timer { font-family: var(--font-display); font-size: 1.1rem; color: var(--ink); }
.question-area { margin-bottom: 1rem; }
.question-text { font-size: 1.25rem; line-height: 1.6; margin-bottom: 1.25rem; }
.answer-area { display: flex; gap: .75rem; align-items: flex-start; }
.answer-inputs-wrap { flex: 1; display: flex; flex-direction: column; gap: .5rem; }
.answer-input {
  width: 100%; font-family: var(--font-serif); font-size: 1.1rem;
  padding: .6rem 1rem; border: 1px solid var(--border); border-radius: 6px;
  background: var(--paper); color: var(--ink);
}
.answer-input:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 2px rgba(139,37,0,.15); }

/* 按钮 */
.btn {
  font-family: var(--font-serif); font-size: .95rem; padding: .5rem 1.25rem;
  border: none; border-radius: 6px; cursor: pointer; min-height: 44px;
  transition: background .2s, transform .1s;
}
.btn:active { transform: scale(.98); }
.btn-check { background: var(--accent); color: #fff; }
.btn-check:hover { background: var(--accent-light); }
.btn-next { background: var(--ink); color: #fff; margin-top: 1rem; }
.btn-next:hover { background: #333; }
.btn-back-home { background: var(--paper-dark); color: var(--ink); border: 1px solid var(--border); }
.btn-back-home:hover { border-color: var(--accent); }
.btn-hint {
  margin-top: .65rem; background: transparent; color: var(--accent);
  border: 1px dashed var(--accent); font-size: .88rem; padding: .35rem 1rem; min-height: 40px;
}
.btn-hint:hover { background: rgba(139,37,0,.06); }
.btn-hint.hint-revealed { background: rgba(139,37,0,.08); border-style: solid; font-weight: 600; }

/* 地支图 */
.dizhi-diagram-area { text-align: center; padding: 1rem 0; }
.dizhi-hint { font-size: .95rem; color: var(--accent); margin: 0 0 1rem; }
.dizhi-diagram { position: relative; margin: 0 auto 1.5rem; }
.dizhi-diagram.dizhi-square { width: 280px; height: 280px; border: 2px solid var(--border); border-radius: 8px; background: linear-gradient(135deg,#faf8f5 0%,#f5f0e6 100%); }
.dizhi-diagram.dizhi-circle { width: 280px; height: 280px; border: 2px solid var(--border); border-radius: 50%; background: linear-gradient(135deg,#faf8f5 0%,#f5f0e6 100%); }
.dizhi-direction { position: absolute; font-size: .7rem; color: var(--border); pointer-events: none; user-select: none; }
.dir-n { top: -18px; left: 50%; transform: translateX(-50%); }
.dir-s { bottom: -18px; left: 50%; transform: translateX(-50%); }
.dir-e { top: 50%; right: -18px; transform: translateY(-50%); }
.dir-w { top: 50%; left: -18px; transform: translateY(-50%); }
.dizhi-cell {
  position: absolute; width: 36px; height: 36px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem; font-weight: 600; color: var(--ink);
  background: var(--paper); border: 1px solid var(--border); border-radius: 4px;
  transform: translate(-50%,-50%);
}
.dizhi-circle .dizhi-cell { border-radius: 50%; background: #fff; box-shadow: 0 1px 3px var(--shadow); }
.dizhi-cell-hidden { color: var(--border); font-size: .85rem; border-style: dashed; }
.dizhi-input { width: 100%; height: 100%; font-family: var(--font-serif); font-size: 1rem; text-align: center; border: none; background: transparent; color: var(--ink); }
.dizhi-input:focus { outline: 2px solid var(--accent); outline-offset: -2px; border-radius: inherit; }
.dizhi-input.hint-placeholder::placeholder { color: var(--accent); opacity: .45; }
.dizhi-actions { display: flex; flex-direction: column; align-items: center; gap: .5rem; }

/* 反馈 & 统计 */
.feedback-area { margin-top: 1rem; }
.feedback-message { font-size: 1.1rem; font-weight: 600; padding: .5rem 0; }
.feedback-message.correct { color: var(--correct); }
.feedback-message.wrong   { color: var(--wrong); }
.stats-bar { margin-top: 1.5rem; padding-top: 1rem; border-top: 1px solid var(--border); font-size: .9rem; }
.stats-bar span { margin-right: 1.5rem; }
.stats-bar strong { color: var(--accent); }
#statCorrect { color: var(--correct); }
#statWrong   { color: var(--wrong); }

/* ══════════════════════════════════════
   挑战结果页
══════════════════════════════════════ */
.result-wrap {
  flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 1rem; padding: 2rem 0;
}
.result-mode-name { font-size: .95rem; color: var(--border); letter-spacing: .1em; }
.result-score-big { font-family: var(--font-display); font-size: 5rem; color: var(--accent); line-height: 1; }
.result-score-label { font-size: .9rem; color: var(--border); }
.result-exp-bar-wrap { width: 100%; max-width: 320px; }
.result-exp-label { font-size: .9rem; margin-bottom: .4rem; text-align: center; }
.result-exp-track { height: 10px; background: var(--paper-dark); border-radius: 5px; overflow: hidden; }
.result-exp-fill { height: 100%; background: var(--accent); border-radius: 5px; transition: width 1s ease; }
.result-level-line { font-size: .85rem; color: var(--border); text-align: center; margin-top: .4rem; }
.result-level-up { font-size: 1.1rem; font-weight: 700; color: var(--gold); }
.result-best-badge { font-size: 1rem; color: var(--gold); font-weight: 700; }
.result-actions { display: flex; gap: 1rem; flex-wrap: wrap; justify-content: center; margin-top: .5rem; }

/* ══════════════════════════════════════
   个人主页
══════════════════════════════════════ */
.profile-card {
  background: #fff; border: 1px solid var(--border); border-radius: 10px;
  padding: 1.5rem; text-align: center; box-shadow: 0 4px 20px var(--shadow);
  margin-bottom: 1.25rem;
}
.profile-avatar {
  width: 60px; height: 60px; border: 2px solid var(--border); border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-display); font-size: 1.5rem; color: var(--accent);
  margin: 0 auto .75rem;
}
.profile-nick { font-size: 1.2rem; font-weight: 700; margin-bottom: .2rem; }
.profile-level-name { font-size: .9rem; color: var(--accent); margin-bottom: .75rem; }
.profile-exp-wrap { margin-top: .5rem; }
.profile-exp-track { height: 8px; background: var(--paper-dark); border-radius: 4px; overflow: hidden; margin-bottom: .3rem; }
.profile-exp-fill { height: 100%; background: var(--accent); border-radius: 4px; transition: width .8s ease; }
.profile-exp-text { font-size: .78rem; color: var(--border); }

.profile-stats-grid { display: grid; grid-template-columns: 1fr 1fr; gap: .75rem; margin-bottom: 1.25rem; }
.pstat-card {
  background: #fff; border: 1px solid var(--border); border-radius: 8px;
  padding: .85rem; text-align: center; box-shadow: 0 2px 8px var(--shadow);
  display: flex; flex-direction: column; gap: .3rem;
}
.pstat-label { font-size: .75rem; color: var(--border); }
.pstat-value { font-family: var(--font-display); font-size: 1.4rem; color: var(--ink); font-weight: 700; }
.pstat-correct { color: var(--correct); }
.pstat-accent   { color: var(--accent); }

/* 历史战绩 */
.history-section { margin-top: .5rem; }
.history-title { font-size: .9rem; font-weight: 700; color: var(--border); letter-spacing: .1em; margin-bottom: .75rem; }
.history-list { display: flex; flex-direction: column; gap: .5rem; }
.history-item {
  background: #fff; border: 1px solid var(--border); border-radius: 6px;
  padding: .6rem .85rem; display: flex; justify-content: space-between; align-items: center;
  font-size: .85rem;
}
.hitem-mode { color: var(--border); font-size: .78rem; }
.hitem-score { font-weight: 700; color: var(--accent); }
.hitem-exp { font-size: .78rem; color: var(--correct); }

/* ══════════════════════════════════════
   排行榜
══════════════════════════════════════ */
.lb-tabs {
  display: flex; gap: .4rem; flex-wrap: wrap; margin-bottom: .75rem;
}
.lb-tab {
  flex: 1; min-width: 60px;
  padding: .45rem .5rem; font-family: var(--font-display); font-size: .95rem;
  background: #fff; border: 1.5px solid var(--border); border-radius: 6px;
  cursor: pointer; transition: border-color .2s, background .2s;
}
.lb-tab:hover  { border-color: var(--accent); }
.lb-tab.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.lb-tab-desc { font-size: .8rem; color: var(--border); margin-bottom: .75rem; }
.lb-loading { text-align: center; color: var(--border); padding: 2rem; }
.lb-offline-tip {
  background: rgba(139,37,0,.06); border: 1px solid var(--accent);
  border-radius: 8px; padding: 1.5rem; font-size: .9rem;
  line-height: 1.7; color: var(--ink); text-align: center;
}
.lb-offline-tip code { background: var(--paper-dark); padding: .1rem .4rem; border-radius: 3px; font-size: .85rem; }
.lb-list { display: flex; flex-direction: column; gap: .5rem; }
.lb-row {
  display: grid; grid-template-columns: 2rem 1fr auto auto;
  align-items: center; gap: .75rem;
  background: #fff; border: 1px solid var(--border); border-radius: 6px;
  padding: .6rem .85rem; font-size: .9rem;
}
.lb-row.me { border-color: var(--accent); background: rgba(139,37,0,.04); }
.lb-rank { font-family: var(--font-display); font-weight: 700; color: var(--border); text-align: right; }
.lb-rank.top1 { color: #b8860b; }
.lb-rank.top2 { color: #808080; }
.lb-rank.top3 { color: #a0522d; }
.lb-nick { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-weight: 600; }
.lb-level { font-size: .78rem; color: var(--accent); }
.lb-score { font-family: var(--font-display); font-size: 1rem; font-weight: 700; color: var(--accent); text-align: right; }

/* ══════════════════════════════════════
   退出确认弹窗
══════════════════════════════════════ */
.modal-overlay {
  position: fixed; inset: 0; z-index: 999;
  background: rgba(26,26,26,.45);
  display: flex; align-items: center; justify-content: center;
  padding: 1.5rem;
}
.modal-box {
  background: var(--paper); border: 1px solid var(--border);
  border-radius: 10px; padding: 1.75rem 1.5rem;
  box-shadow: 0 8px 32px rgba(26,26,26,.18);
  max-width: 320px; width: 100%;
}
.modal-msg {
  margin: 0 0 1.25rem; font-size: 1rem; line-height: 1.6;
  text-align: center; color: var(--ink);
}
.modal-actions { display: flex; gap: .75rem; justify-content: center; }
.modal-actions .btn { flex: 1; }

/* ══════════════════════════════════════
   Footer
══════════════════════════════════════ */
.footer { margin-top: auto; padding-top: 2rem; text-align: center; font-size: .8rem; color: var(--border); }

/* ══════════════════════════════════════
   响应式
══════════════════════════════════════ */
@media (max-width: 768px) {
  .dizhi-diagram.dizhi-square,
  .dizhi-diagram.dizhi-circle { width: min(280px,calc(100vw - 5rem)); height: min(280px,calc(100vw - 5rem)); }
}

@media (max-width: 480px) {
  .app { padding: 0 .9rem; }
  .screen { padding: 1.25rem 0; }
  .title { font-size: 1.4rem; }
  .mode-grid { gap: .75rem; }
  .mode-card { padding: 1.5rem .75rem; }
  .mode-icon { font-size: 2rem; }
  .mode-card-challenge { flex-direction: column; }
  .challenge-mode-grid { grid-template-columns: 1fr; }
  .quiz-card { padding: 1rem; }
  .question-text { font-size: 1.1rem; }
  .answer-area { flex-direction: column; align-items: stretch; }
  .btn-check, .btn-next, .btn-hint { width: 100%; text-align: center; }
  .dizhi-diagram.dizhi-square,
  .dizhi-diagram.dizhi-circle { width: min(260px,calc(100vw - 4rem)); height: min(260px,calc(100vw - 4rem)); }
  .profile-stats-grid { grid-template-columns: 1fr 1fr; }
  .lb-tabs { gap: .3rem; }
  .lb-tab { font-size: .85rem; padding: .4rem .4rem; }
}

@media (max-width: 360px) {
  .title { font-size: 1.2rem; }
  .question-text { font-size: 1rem; }
  .mode-grid { grid-template-columns: 1fr; }
  .dizhi-diagram.dizhi-square,
  .dizhi-diagram.dizhi-circle { width: calc(100vw - 3.5rem); height: calc(100vw - 3.5rem); }
}