/* =====================================================================
   四级通关多人备考平台 - 主样式
   风格：浅蓝白色学习风，简约现代，PC/手机自适应
   ===================================================================== */
@import url("https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500;700&display=swap");
:root{
  --c-primary:#4a90e2;
  --c-primary-dark:#2f6fc0;
  --c-primary-light:#eaf3ff;
  --c-success:#42c878;
  --c-warning:#f0a93b;
  --c-danger:#e85c5c;
  --c-bg:#f5f9ff;
  --c-text:#2c3e50;
  --c-muted:#8aa0b3;
  --radius:12px;
  --shadow:0 2px 14px rgba(74,144,226,.12);
}
*{box-sizing:border-box;}
body{
  background:var(--c-bg);
  color:var(--c-text);
  font-family:"Noto Sans SC",-apple-system,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  font-size:15px;
  margin:0;
  min-height:100vh;
}
a{color:var(--c-primary-dark);text-decoration:none;}
a:hover{color:var(--c-primary);}

/* === 顶栏 === */
.topbar{
  height:56px;background:linear-gradient(90deg,#4a90e2,#5eb0f0);
  color:#fff;box-shadow:0 2px 8px rgba(74,144,226,.18);
  position:sticky;top:0;z-index:1000;
}
.topbar .brand{
  color:#fff;font-weight:700;font-size:18px;display:flex;align-items:center;gap:8px;
}
.topbar .brand i{font-size:22px;}
.top-nav a{
  color:rgba(255,255,255,.88);padding:6px 12px;border-radius:8px;font-size:14px;
  display:inline-flex;align-items:center;gap:4px;transition:.2s;
}
.top-nav a:hover{background:rgba(255,255,255,.18);color:#fff;}
.top-nav a.active{background:rgba(255,255,255,.28);color:#fff;font-weight:600;}
.user-chip{display:flex;align-items:center;gap:8px;color:#fff;cursor:pointer;padding:4px 8px;border-radius:20px;}
.user-chip:hover{background:rgba(255,255,255,.18);}
.avatar{
  width:32px;height:32px;border-radius:50%;background:#fff;color:var(--c-primary);
  display:flex;align-items:center;justify-content:center;font-weight:700;font-size:14px;
}
.uname{font-size:14px;}
.bg-stage-基础{background:#4a90e2!important;}
.bg-stage-强化{background:#f0a93b!important;}
.bg-stage-冲刺{background:#e85c5c!important;}

/* === 移动端底部导航 === */
.mobile-nav{position:fixed;bottom:0;left:0;right:0;background:#fff;
  box-shadow:0 -2px 10px rgba(0,0,0,.08);z-index:999;display:none;
  overflow-x:auto;-webkit-overflow-scrolling:touch;white-space:nowrap;}
.mobile-nav a{display:inline-flex;flex-direction:column;align-items:center;
  padding:8px 0;font-size:11px;color:var(--c-muted);min-width:64px;flex:none;}
.mobile-nav a i{display:block;font-size:20px;color:var(--c-primary);margin-bottom:2px;}
@media(max-width:991px){.mobile-nav{display:flex;}body{padding-bottom:80px;}.main-wrap{padding-bottom:20px;}.footer{margin-bottom:0;}}

/* === 主区 === */
.main-wrap{min-height:calc(100vh - 56px);}
.main-wrap.bare{display:flex;align-items:center;justify-content:center;min-height:100vh;background:linear-gradient(135deg,#eaf3ff,#f5f9ff);}

/* === 卡片 === */
.card{border:none;border-radius:var(--radius);box-shadow:var(--shadow);}
.card-header{background:#fff;border-bottom:1px solid #eef3fa;font-weight:600;border-radius:var(--radius) var(--radius) 0 0!important;}
.card-header a{color:inherit;}

/* === 首页看板 === */
.stat-card{border-radius:var(--radius);padding:18px 20px;color:#fff;position:relative;overflow:hidden;}
.stat-card i.bg-icon{position:absolute;right:10px;bottom:-6px;font-size:60px;opacity:.18;}
.stat-card .num{font-size:28px;font-weight:700;line-height:1;}
.stat-card .lbl{font-size:13px;opacity:.9;margin-top:6px;}
.stat-card.vocab{background:linear-gradient(135deg,#5b8def,#8eabf5);}
.stat-card.exam{background:linear-gradient(135deg,#42c878,#67d596);}
.stat-card.clock{background:linear-gradient(135deg,#f0a93b,#ffc06b);}
.stat-card.wrong{background:linear-gradient(135deg,#e85c5c,#f08585);}

/* 快捷入口 */
.quick-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:14px;}
.quick-item{
  background:#fff;border-radius:var(--radius);padding:20px 10px;text-align:center;
  color:var(--c-text);box-shadow:var(--shadow);transition:.2s;cursor:pointer;
}
.quick-item:hover{transform:translateY(-3px);border:1px solid var(--c-primary-light);color:var(--c-primary-dark);}
.quick-item i{font-size:28px;color:var(--c-primary);display:block;margin-bottom:8px;}
.quick-item span{font-size:13px;}

/* === 计划 === */
.task-row{display:flex;align-items:center;gap:10px;padding:10px;border-radius:8px;background:#fff;margin-bottom:8px;}
.task-row.done{background:#f5fbf6;}
.task-row .check{width:22px;height:22px;border:2px solid #c7d6e8;border-radius:50%;cursor:pointer;display:flex;align-items:center;justify-content:center;}
.task-row.done .check{background:var(--c-success);border-color:var(--c-success);color:#fff;}
.task-row .info{flex:1;}
.task-row .info .t{font-weight:600;}
.task-row .info .d{font-size:12px;color:var(--c-muted);}

/* === 单词卡 === */
.vocab-card{
  background:#fff;border-radius:var(--radius);padding:32px 24px;text-align:center;
  box-shadow:var(--shadow);max-width:520px;margin:0 auto;min-height:280px;
  display:flex;flex-direction:column;justify-content:center;
}
.vocab-card .word{font-size:42px;font-weight:700;color:var(--c-primary-dark);margin-bottom:6px;}
.vocab-card .phon{color:var(--c-muted);font-size:16px;margin-bottom:14px;}
.vocab-card .meaning{font-size:18px;color:var(--c-text);}
.vocab-card .ex{margin-top:14px;padding:10px;background:var(--c-primary-light);border-radius:8px;font-size:14px;color:#5a6c7d;text-align:left;}
.vocab-review-badge{display:inline-block;background:var(--c-warning,#f59e0b);color:#fff;font-size:13px;padding:2px 10px;border-radius:12px;vertical-align:middle;margin-right:8px;font-weight:600;line-height:1.4;}
.vocab-review-badge i{margin-right:2px;}
.vocab-freq-badge{display:inline-block;font-size:12px;padding:2px 8px;border-radius:6px;margin-left:10px;font-weight:600;vertical-align:middle;line-height:1.6;white-space:nowrap;}
.vocab-freq-badge.freq-high{background:#e8f5e9;color:#2e7d32;}
.vocab-freq-badge.freq-mid{background:#fff8e1;color:#e65100;}
.vocab-freq-badge.freq-low{background:#fce4ec;color:#ad1457;}
.sentence-comic{margin-top:14px;text-align:center;}
.sentence-comic img{max-width:100%;border-radius:12px;box-shadow:var(--shadow);border:3px solid var(--c-primary-light);}

/* === 单词卡 - 记忆辅助字段 (词根词缀/联想记忆/派生词/常考搭配) === */
.vocab-card .meta-row{margin-top:10px;font-size:13px;line-height:1.55;text-align:left;padding:8px 12px;border-radius:8px;display:flex;gap:6px;align-items:flex-start;}
.vocab-card .meta-row .meta-label{flex:0 0 auto;font-weight:700;white-space:nowrap;}
.vocab-card .meta-row .meta-body{flex:1 1 auto;word-break:break-word;}
.vocab-card .meta-row.root { background:#fff7e6; color:#8a5a00; }
.vocab-card .meta-row.root .meta-label { color:var(--c-warning); }
.vocab-card .meta-row.mnemo{ background:var(--c-primary-light); color:#1e4a82; }
.vocab-card .meta-row.mnemo .meta-label { color:var(--c-primary-dark); }
.vocab-card .meta-row.deriv{ background:#eafaf1; color:#1f6a3c; }
.vocab-card .meta-row.deriv .meta-label { color:var(--c-success); }
.vocab-card .meta-row.coll { background:#f3f5f8; color:#3d4a5c; }
.vocab-card .meta-row.coll .meta-label { color:var(--c-muted); }
.vocab-card .meta-row.syn  { background:#f3e8ff; color:#6b21a8; }
.vocab-card .meta-row.syn .meta-label { color:#9333ea; }
.vocab-card .meta-row.ant  { background:#fde8f0; color:#9d174d; }
.vocab-card .meta-row.ant .meta-label { color:#be185d; }

/* === 词汇筛选条 === */
.vocab-filter-bar{
  padding:10px 16px;background:#f8f9fb;border-top:1px solid #eef2f7;border-bottom:1px solid #eef2f7;
}
.vocab-filter-row{
  display:flex;align-items:center;gap:6px;flex-wrap:wrap;
}
.vocab-filter-row + .vocab-filter-row{margin-top:6px;}
.vocab-filter-label{
  flex:0 0 auto;font-size:12px;color:var(--c-muted);font-weight:600;
  min-width:32px;padding:2px 0;
}
.vocab-filter-btn{
  border:1px solid #dde3ec;background:#fff;color:#5a6c7d;
  padding:3px 10px;font-size:12px;border-radius:14px;cursor:pointer;
  transition:all .15s ease;white-space:nowrap;line-height:1.4;
}
.vocab-filter-btn:hover{border-color:var(--c-primary);color:var(--c-primary-dark);}
.vocab-filter-btn.active{
  background:var(--c-primary);border-color:var(--c-primary);color:#fff;
  box-shadow:0 1px 4px rgba(46,91,158,.25);
}
/* 移动端筛选条横向滚动 */
@media (max-width:575.98px){
  .vocab-filter-bar{padding:8px 12px;}
  .vocab-filter-row{flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch;}
  .vocab-filter-row::-webkit-scrollbar{height:3px;}
  .vocab-filter-label{flex:0 0 auto;}
  .vocab-filter-btn{flex:0 0 auto;}
}

/* === 选择题 === */
.quiz-toolbar{padding:0 4px;}
.quiz-score .badge{font-size:13px;min-width:28px;}
.quiz-card{
  background:#fff;border-radius:var(--radius);padding:28px 24px;text-align:center;
  box-shadow:var(--shadow);max-width:560px;margin:0 auto;min-height:200px;
}
.quiz-question{margin-bottom:20px;}
.quiz-word{font-size:36px;font-weight:700;color:var(--c-primary-dark);margin-bottom:4px;}
.quiz-meaning{font-size:22px;font-weight:600;color:var(--c-text);margin-bottom:4px;line-height:1.4;}
.quiz-phon{color:var(--c-muted);font-size:15px;margin-bottom:8px;}
.quiz-prompt{font-size:14px;color:var(--c-muted);margin-top:6px;}
.quiz-options{display:flex;flex-direction:column;gap:10px;margin-top:8px;}
.quiz-opt{
  display:flex;align-items:center;gap:12px;padding:12px 18px;
  background:#f8fafe;border:2px solid #e3edf7;border-radius:12px;
  cursor:pointer;transition:all .18s;font-size:16px;text-align:left;
  color:var(--c-text);
}
.quiz-opt:hover{background:var(--c-primary-light);border-color:var(--c-primary);}
.quiz-opt:active{transform:scale(.97);}
.quiz-opt-label{
  flex:0 0 32px;height:32px;border-radius:50%;background:var(--c-primary-light);
  color:var(--c-primary-dark);font-weight:700;font-size:14px;
  display:flex;align-items:center;justify-content:center;
}
.quiz-opt-text{flex:1;word-break:break-word;}
/* 选项状态 */
.quiz-opt-correct{background:#e8f8ee!important;border-color:var(--c-success)!important;}
.quiz-opt-correct .quiz-opt-label{background:var(--c-success);color:#fff!important;}
.quiz-opt-wrong{background:#fde8e8!important;border-color:var(--c-danger)!important;}
.quiz-opt-wrong .quiz-opt-label{background:var(--c-danger);color:#fff!important;}
.quiz-opt-dim{opacity:.5;pointer-events:none;}
/* 反馈 */
.quiz-feedback{margin-top:16px;padding:12px 16px;border-radius:10px;font-size:15px;}
.quiz-fb-correct{color:var(--c-success);font-weight:600;}
.quiz-fb-correct i{margin-right:6px;}
.quiz-fb-wrong{color:var(--c-danger);font-weight:600;}
.quiz-fb-wrong i{margin-right:6px;}
.quiz-fb-wrong b{color:var(--c-success);}
/* 成绩 */
.quiz-result{padding:20px 0;}
.quiz-result-emoji{font-size:56px;margin-bottom:8px;}
.quiz-result-score{font-size:40px;font-weight:700;color:var(--c-primary-dark);}
.quiz-result-pct{font-size:18px;color:var(--c-muted);margin-top:4px;}
.quiz-result-msg{font-size:16px;color:var(--c-text);margin-top:10px;font-weight:600;}
.quiz-result-title{font-size:20px;font-weight:700;color:var(--c-primary-dark);margin-bottom:12px;}
/* 累计成绩 */
.quiz-result-cum{font-size:15px;color:var(--c-muted);margin-top:8px;}
/* 批次过场 */
.quiz-batch-inner{padding:20px 0;animation:quizFadeIn .3s ease;}
.quiz-batch-inner .quiz-result-msg{color:var(--c-muted);font-weight:400;font-size:14px;margin-top:14px;}
/* 暂停面板 */
.quiz-paused-inner{padding:24px 0;animation:quizFadeIn .25s ease;}
.quiz-paused-btns{display:flex;justify-content:center;flex-wrap:wrap;}
@keyframes quizFadeIn{from{opacity:0;transform:translateY(8px);}to{opacity:1;transform:translateY(0);}}

/* === 表单 === */
.form-control:focus,.form-select:focus{border-color:var(--c-primary);box-shadow:0 0 0 .2rem rgba(74,144,226,.18);}
.btn-primary{background:var(--c-primary);border-color:var(--c-primary);transition:transform .15s ease,background .15s ease;}
.btn-primary:hover{background:var(--c-primary-dark);border-color:var(--c-primary-dark);transform:translateY(-1px);}
.btn-primary:active{transform:translateY(0) scale(.98);}

/* === 答题 === */
.q-block{background:#fff;border-radius:var(--radius);padding:18px 22px;margin-bottom:14px;box-shadow:var(--shadow);}
.q-block .q-stem{font-weight:600;margin-bottom:12px;}
.q-block .opts label{display:block;padding:8px 12px;border:1px solid #e3edf7;border-radius:8px;margin-bottom:6px;cursor:pointer;transition:.15s;}
.q-block .opts label:hover{background:var(--c-primary-light);}
.q-block .opts input{margin-right:8px;}
.q-block.correct{border-left:4px solid var(--c-success);}
.q-block.wrong{border-left:4px solid var(--c-danger);}
.q-block .ans-tip{margin-top:10px;padding:8px 12px;border-radius:6px;font-size:14px;}

/* === PDF阅读器 === */
.pdf-viewer{width:100%;border:0;border-radius:var(--radius);box-shadow:var(--shadow);}

/* === 通用 === */
.text-primary{color:var(--c-primary)!important;}
.btn-sm-rounded{border-radius:20px;padding:4px 14px;}
.empty-state{text-align:center;padding:40px 20px;color:var(--c-muted);}
.empty-state i{font-size:48px;display:block;margin-bottom:12px;}
.section-title{font-size:16px;font-weight:700;margin:18px 0 12px;padding-left:10px;border-left:4px solid var(--c-primary);}
.tag{display:inline-block;padding:2px 8px;background:var(--c-primary-light);color:var(--c-primary-dark);border-radius:10px;font-size:12px;margin-right:4px;}
.table th{background:var(--c-primary-light);font-weight:600;}
.footer{padding:18px 0;color:var(--c-muted);}
.footer a{color:var(--c-muted);}
.list-group-item{border-color:#e3edf7;}

/* 夜间模式（PDF阅读器用） */
.dark-mode{background:#1a1a1a;color:#eee;}
.dark-mode .card,.dark-mode .q-block{background:#2a2a2a;color:#eee;}

/* 倒计时大字 */
.countdown-box{text-align:center;background:linear-gradient(135deg,#4a90e2,#5eb0f0);color:#fff;border-radius:var(--radius);padding:24px;margin-bottom:18px;}
.countdown-box .num{font-size:48px;font-weight:700;line-height:1;}
.countdown-box .lbl{font-size:14px;opacity:.9;margin-top:6px;}

/* =====================================================================
   手机端响应式修复（iPhone 15/16 · 390px~430px）
   ===================================================================== */
@media(max-width:991px){
  /* --- 顶栏 --- */
  .topbar{height:auto;min-height:52px;padding:8px 12px;}
  .topbar .container-fluid{flex-wrap:wrap;gap:4px;}
  .topbar .brand{font-size:15px;gap:6px;flex:1 1 auto;min-width:0;}
  .topbar .brand i{font-size:18px;}
  .topbar .brand span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap;}
  .topbar .ms-auto{flex:0 0 auto;gap:6px;}
  .user-chip{gap:4px;padding:2px 6px;}
  .uname{font-size:12px;max-width:48px;overflow:hidden;text-overflow:ellipsis;}
  .avatar{width:28px;height:28px;font-size:12px;}
  .topbar .badge{font-size:11px;padding:3px 6px;}
  .dropdown-menu{min-width:140px;}

  /* --- 单词卡 --- */
  .vocab-card{padding:18px 14px;min-height:auto;max-width:100%;}
  .vocab-card .word{font-size:32px;margin-bottom:4px;}
  .vocab-card .phon{font-size:14px;margin-bottom:10px;}
  .vocab-card .meaning{font-size:16px;}
  .vocab-card .ex{font-size:13px;padding:8px;}
  .vocab-card .meta-row{font-size:12px;padding:6px 10px;}
  .btn-sm-rounded{padding:6px 12px;font-size:13px;min-height:48px;display:inline-flex;align-items:center;}

  /* --- 选择题 --- */
  .quiz-card{padding:16px 12px;max-width:100%;}
  .quiz-word{font-size:28px;}
  .quiz-meaning{font-size:18px;}
  .quiz-opt{padding:10px 12px;font-size:14px;gap:8px;min-height:48px;}
  .quiz-opt-label{width:28px;height:28px;flex:0 0 28px;font-size:12px;}
  .quiz-toolbar{flex-direction:column;align-items:flex-start;gap:8px;}
  .quiz-score .badge{font-size:12px;min-width:22px;}
  .quiz-score .text-muted.small{font-size:11px;}
  .quiz-result-score{font-size:32px;}
  .quiz-result-emoji{font-size:44px;}

  /* --- 首页快捷入口 --- */
  .quick-grid{grid-template-columns:repeat(3,1fr);gap:10px;}
  .quick-item{padding:14px 6px;}
  .quick-item i{font-size:24px;margin-bottom:4px;}
  .quick-item span{font-size:12px;}

  /* --- 倒计时 --- */
  .countdown-box{padding:16px 14px;}
  .countdown-box .num{font-size:36px;}
  .countdown-box .lbl{font-size:13px;}

  /* --- 首页数据看板 --- */
  .stat-card{padding:12px 14px;}
  .stat-card .num{font-size:24px;}
  .stat-card .lbl{font-size:12px;}
  .stat-card i.bg-icon{font-size:40px;}

  /* --- 金句列表 --- */
  .btn-group.btn-group-sm .btn{font-size:12px;padding:4px 8px;}
  .btn-group.btn-group-sm{flex-wrap:wrap;gap:4px;}
  .list-group-item .text-body{font-size:14px!important;line-height:1.5!important;}
  .list-group-item .text-muted{font-size:13px!important;line-height:1.4!important;}

  /* --- 通用 --- */
  .card-body{padding:12px;}
  .footer{padding:12px 0;font-size:12px;}
  .footer .container{white-space:normal;}
  .footer .container span{display:inline-block;margin:2px 0;}
  .empty-state{padding:24px 16px;}
  .empty-state i{font-size:36px;}
  .btn{min-height:38px;}  /* 移动端按钮最小高度 */
  .btn-sm{min-height:36px;}
  .btn-sm-rounded{min-height:48px;display:inline-flex;align-items:center;}
}
@media(max-width:400px){
  /* 超小屏（iPhone SE / mini）额外压缩 */
  .topbar .brand{font-size:14px;}
  .quick-grid{grid-template-columns:repeat(3,1fr);gap:8px;}
  .quiz-opt{padding:8px 10px;font-size:13px;min-height:48px;}
}