/* ========== 全局变量与重置 ========== */
:root{
  --primary:#6366f1;
  --primary-dark:#4f46e5;
  --primary-light:#818cf8;
  --accent:#f59e0b;
  --accent-light:#fbbf24;
  --success:#10b981;
  --danger:#ef4444;
  --warning:#f59e0b;
  --info:#3b82f6;
  --bg:#f8fafc;
  --bg-2:#f1f5f9;
  --card:#ffffff;
  --text:#1e293b;
  --text-2:#64748b;
  --text-3:#94a3b8;
  --border:#e2e8f0;
  --shadow:0 4px 6px -1px rgba(0,0,0,.07),0 2px 4px -2px rgba(0,0,0,.05);
  --shadow-lg:0 20px 25px -5px rgba(0,0,0,.08),0 8px 10px -6px rgba(0,0,0,.05);
  --radius:16px;
  --radius-sm:10px;
  --gradient:linear-gradient(135deg,#6366f1 0%,#8b5cf6 50%,#ec4899 100%);
  --gradient-2:linear-gradient(135deg,#06b6d4 0%,#6366f1 100%);
}
*{margin:0;padding:0;box-sizing:border-box}
html{font-size:16px;-webkit-text-size-adjust:100%}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  color:var(--text);background:var(--bg);line-height:1.6;overflow-x:hidden;
  min-height:100vh;
}
a{color:var(--primary);text-decoration:none;transition:.2s}
a:hover{color:var(--primary-dark)}
img{max-width:100%;height:auto;display:block}
button{cursor:pointer;font-family:inherit;border:none;background:none}
input,select,textarea{font-family:inherit;font-size:1rem;color:var(--text)}
ul{list-style:none}

/* ========== 3D 动态背景 ========== */
.bg-3d{position:fixed;inset:0;z-index:-2;overflow:hidden;
  background:linear-gradient(135deg,#eef2ff 0%,#fdf4ff 50%,#ecfeff 100%);}
.bg-3d .orb{position:absolute;border-radius:50%;filter:blur(60px);opacity:.5;
  animation:float 12s ease-in-out infinite}
.bg-3d .orb-1{width:400px;height:400px;background:radial-gradient(circle,#818cf8,transparent);top:-100px;left:-100px;animation-delay:0s}
.bg-3d .orb-2{width:350px;height:350px;background:radial-gradient(circle,#f0abfc,transparent);bottom:-80px;right:-80px;animation-delay:-4s}
.bg-3d .orb-3{width:300px;height:300px;background:radial-gradient(circle,#67e8f9,transparent);top:40%;left:60%;animation-delay:-8s}
@keyframes float{0%,100%{transform:translate(0,0) scale(1)}50%{transform:translate(40px,-30px) scale(1.1)}}

/* 漂浮单词3D层 */
.floating-words{position:fixed;inset:0;z-index:-1;pointer-events:none;perspective:1000px}
.floating-words span{position:absolute;font-weight:700;color:var(--primary);opacity:.08;
  animation:float3d 20s linear infinite;transform-style:preserve-3d;font-size:1.5rem}
@keyframes float3d{
  0%{transform:translateY(110vh) rotateY(0deg) rotateX(20deg)}
  100%{transform:translateY(-10vh) rotateY(360deg) rotateX(-20deg)}
}

/* ========== 顶部导航 ========== */
.navbar{position:sticky;top:0;z-index:100;backdrop-filter:blur(16px);
  background:rgba(255,255,255,.8);border-bottom:1px solid var(--border);}
.nav-inner{max-width:1200px;margin:0 auto;display:flex;align-items:center;justify-content:space-between;
  padding:.8rem 1.2rem;gap:1rem}
.logo{display:flex;align-items:center;gap:.6rem;font-weight:800;font-size:1.25rem;color:var(--text)}
.logo-icon{width:38px;height:38px;border-radius:11px;background:var(--gradient);
  display:flex;align-items:center;justify-content:center;color:#fff;font-weight:800;
  box-shadow:0 4px 14px rgba(99,102,241,.4);transform-style:preserve-3d;
  animation:logoSpin 8s linear infinite}
@keyframes logoSpin{from{transform:rotateY(0)}to{transform:rotateY(360deg)}}
.logo-text{background:var(--gradient);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent}
.nav-menu{display:flex;gap:.3rem;align-items:center}
.nav-menu a{padding:.5rem .9rem;border-radius:10px;color:var(--text-2);font-weight:500;font-size:.92rem}
.nav-menu a:hover,.nav-menu a.active{background:var(--bg-2);color:var(--primary)}
.nav-user{display:flex;align-items:center;gap:.6rem}
.avatar{width:36px;height:36px;border-radius:50%;background:var(--gradient-2);
  display:flex;align-items:center;justify-content:center;color:#fff;font-weight:700;font-size:.9rem}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:.5rem;
  padding:.65rem 1.3rem;border-radius:12px;font-weight:600;font-size:.92rem;
  transition:all .25s;white-space:nowrap;border:1px solid transparent}
.btn-primary{background:var(--gradient);color:#fff;box-shadow:0 4px 14px rgba(99,102,241,.35)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 8px 22px rgba(99,102,241,.45)}
.btn-ghost{background:var(--bg-2);color:var(--text)}
.btn-ghost:hover{background:var(--border)}
.btn-outline{border-color:var(--border);color:var(--text);background:#fff}
.btn-outline:hover{border-color:var(--primary);color:var(--primary)}
.btn-success{background:var(--success);color:#fff}
.btn-sm{padding:.4rem .9rem;font-size:.85rem}
.btn-block{width:100%}

/* 汉堡菜单 */
.menu-toggle{display:none;flex-direction:column;gap:5px;padding:.4rem}
.menu-toggle span{width:24px;height:2.5px;background:var(--text);border-radius:2px;transition:.3s}

/* ========== 容器 ========== */
.container{max-width:1200px;margin:0 auto;padding:1.5rem 1.2rem}
.page-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:1.5rem;flex-wrap:wrap;gap:1rem}
.page-title{font-size:1.6rem;font-weight:800}
.page-sub{color:var(--text-2);font-size:.9rem;margin-top:.2rem}

/* ========== 卡片 ========== */
.card{background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);
  border:1px solid rgba(255,255,255,.6);overflow:hidden;transition:transform .3s,box-shadow .3s}
.card:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg)}
.card-body{padding:1.3rem}
.card-head{display:flex;align-items:center;justify-content:space-between;padding:1.1rem 1.3rem;border-bottom:1px solid var(--border)}
.card-head h3{font-size:1.05rem;font-weight:700}

/* ========== 统计卡片 ========== */
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:1rem}
.stat-card{background:var(--card);border-radius:var(--radius);padding:1.3rem;box-shadow:var(--shadow);
  position:relative;overflow:hidden;border:1px solid var(--border)}
.stat-card::before{content:"";position:absolute;top:0;left:0;width:4px;height:100%;background:var(--gradient)}
.stat-num{font-size:2rem;font-weight:800;line-height:1.1}
.stat-label{color:var(--text-2);font-size:.85rem;margin-top:.3rem}
.stat-icon{position:absolute;right:1rem;top:50%;transform:translateY(-50%);width:48px;height:48px;
  border-radius:14px;background:var(--bg-2);display:flex;align-items:center;justify-content:center;font-size:1.4rem}

/* ========== 词卡3D翻转 ========== */
.word-card-3d{perspective:1200px;width:100%;max-width:520px;margin:0 auto;min-height:340px}
.word-card-inner{position:relative;width:100%;min-height:340px;transition:transform .7s cubic-bezier(.4,.2,.2,1);
  transform-style:preserve-3d;cursor:pointer}
.word-card-3d.flipped .word-card-inner{transform:rotateY(180deg)}
.word-face{position:absolute;inset:0;border-radius:var(--radius);backface-visibility:hidden;
  display:flex;flex-direction:column;align-items:center;justify-content:center;padding:2rem;
  background:var(--card);box-shadow:var(--shadow-lg);border:1px solid var(--border);text-align:center}
.word-face.back{transform:rotateY(180deg);background:linear-gradient(135deg,#eef2ff,#fdf4ff)}
.word-en{font-size:2.6rem;font-weight:800;letter-spacing:-.5px;margin-bottom:.5rem}
.word-phonetic{color:var(--text-2);font-size:1.05rem;margin-bottom:.8rem}
.word-pos{display:inline-block;padding:.2rem .7rem;border-radius:20px;background:var(--bg-2);
  color:var(--primary);font-size:.8rem;font-weight:600;margin-bottom:1rem}
.word-meaning{font-size:1.3rem;color:var(--text);margin-bottom:1rem}
.word-example{font-size:.92rem;color:var(--text-2);font-style:italic;text-align:center;margin-bottom:.3rem}
.word-example-cn{font-size:.85rem;color:var(--text-3)}
.play-btn{width:52px;height:52px;border-radius:50%;background:var(--gradient);color:#fff;
  display:flex;align-items:center;justify-content:center;font-size:1.2rem;
  box-shadow:0 6px 18px rgba(99,102,241,.4);transition:transform .2s}
.play-btn:hover{transform:scale(1.1)}
.flip-hint{margin-top:1.2rem;font-size:.8rem;color:var(--text-3);animation:pulse 2s infinite}
@keyframes pulse{0%,100%{opacity:.4}50%{opacity:1}}

/* ========== 词根词缀拆解 ========== */
.word-card-3d{min-height:420px}
.word-card-inner{min-height:420px}
.word-face.back{justify-content:flex-start;padding:1.5rem;overflow-y:auto}
.root-section{width:100%;margin-top:1rem;padding-top:.8rem;border-top:1px dashed var(--border)}
.root-summary{font-size:.82rem;color:var(--text-2);margin-bottom:.7rem;text-align:left}
.root-breakdown{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:.3rem;margin-bottom:.4rem}
.morph{display:inline-block;padding:.4rem .8rem;border-radius:10px;font-weight:700;font-size:1.1rem;
  color:#fff;box-shadow:0 3px 10px rgba(0,0,0,.12)}
.morph-prefix{background:linear-gradient(135deg,#f87171,#ef4444)}
.morph-root{background:linear-gradient(135deg,#60a5fa,#3b82f6)}
.morph-suffix{background:linear-gradient(135deg,#a78bfa,#7c3aed)}
.morph-linking{background:linear-gradient(135deg,#fbbf24,#f59e0b);color:#78350f}
.morph-result{background:linear-gradient(135deg,#34d399,#10b981)}
.morph-plus,.morph-eq{font-weight:800;color:var(--text-3);font-size:1.1rem}
.morph-labels{display:flex;justify-content:center;flex-wrap:wrap;gap:.3rem;margin-bottom:.6rem}
.morph-label{font-size:.7rem;color:var(--text-3);padding:.1rem .5rem;background:var(--bg-2);border-radius:6px}
.root-mnemonic{font-size:.85rem;color:#7c3aed;font-weight:600;text-align:left;
  background:#f5f3ff;padding:.5rem .7rem;border-radius:8px;border-left:3px solid #7c3aed}
.deriv-wrap{display:grid;grid-template-columns:1fr 1fr;gap:.8rem;width:100%;margin-top:.8rem}
.deriv-col{text-align:left}
.deriv-title{font-size:.75rem;font-weight:700;color:var(--primary);margin-bottom:.3rem;
  padding-bottom:.2rem;border-bottom:2px solid var(--primary)}
.deriv-item{font-size:.76rem;color:var(--text);line-height:1.5;margin-bottom:.15rem}
.deriv-pos{color:var(--text-3);font-size:.7rem;font-weight:600}
@media(max-width:560px){
  .deriv-wrap{grid-template-columns:1fr}
  .morph{font-size:.95rem;padding:.35rem .6rem}
}

/* ========== 词根图谱页 ========== */
.root-card{background:var(--card);border-radius:var(--radius);padding:1.2rem 1.4rem;
  box-shadow:var(--shadow);border:1px solid var(--border);margin-bottom:1.2rem}
.root-card-head{display:flex;align-items:flex-start;gap:.8rem;margin-bottom:.6rem}
.root-index{flex-shrink:0;width:36px;height:36px;border-radius:10px;
  background:linear-gradient(135deg,#6366f1,#8b5cf6);color:#fff;
  display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.9rem}
.root-word-title{flex:1;min-width:0}
.root-word-en{font-size:1.5rem;font-weight:800;margin-right:.5rem}
.root-word-phon{color:var(--text-2);font-size:.9rem;margin-right:.5rem}
.root-word-pos{display:inline-block;padding:.1rem .5rem;border-radius:10px;
  background:var(--bg-2);color:var(--primary);font-size:.72rem;font-weight:600;margin-right:.5rem}
.root-word-meaning{color:var(--text);font-size:.92rem}
.root-summary-line{font-size:.82rem;color:var(--text-2);margin-bottom:.6rem}
.root-breakdown-row{display:flex;align-items:center;flex-wrap:wrap;gap:.35rem;margin-bottom:.3rem}
.morph-labels-row{display:flex;flex-wrap:wrap;gap:.35rem;margin-bottom:.5rem}
.root-breakdown-row .morph{font-size:1rem;padding:.35rem .7rem}
@media(max-width:560px){
  .root-word-en{font-size:1.25rem}
  .root-breakdown-row .morph{font-size:.88rem;padding:.3rem .55rem}
}

/* ========== 按钮组 ========== */
.action-row{display:flex;gap:.8rem;justify-content:center;margin-top:1.5rem;flex-wrap:wrap}
.feedback-btn{padding:.9rem 1.8rem;border-radius:14px;font-weight:700;font-size:1rem;transition:.2s;
  border:2px solid transparent}
.feedback-btn.know{background:#ecfdf5;color:var(--success);border-color:#a7f3d0}
.feedback-btn.know:hover{background:var(--success);color:#fff}
.feedback-btn.vague{background:#fffbeb;color:var(--warning);border-color:#fde68a}
.feedback-btn.vague:hover{background:var(--warning);color:#fff}
.feedback-btn.forget{background:#fef2f2;color:var(--danger);border-color:#fecaca}
.feedback-btn.forget:hover{background:var(--danger);color:#fff}

/* ========== 底部导航（移动端） ========== */
.tabbar{position:fixed;bottom:0;left:0;right:0;z-index:90;display:none;
  background:rgba(255,255,255,.95);backdrop-filter:blur(16px);border-top:1px solid var(--border);
  padding:.5rem 0 calc(.5rem + env(safe-area-inset-bottom))}
.tabbar-inner{display:flex;justify-content:space-around;max-width:600px;margin:0 auto}
.tab-item{display:flex;flex-direction:column;align-items:center;gap:2px;padding:.3rem .8rem;
  color:var(--text-3);font-size:.72rem;font-weight:500;transition:.2s}
.tab-item .ico{font-size:1.3rem}
.tab-item.active{color:var(--primary)}

/* ========== 表单 ========== */
.form-group{margin-bottom:1.1rem}
.form-label{display:block;margin-bottom:.4rem;font-weight:600;font-size:.9rem}
.form-control{width:100%;padding:.75rem 1rem;border:1.5px solid var(--border);border-radius:12px;
  background:#fff;transition:.2s}
.form-control:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 4px rgba(99,102,241,.12)}
textarea.form-control{resize:vertical;min-height:100px}
.form-hint{font-size:.8rem;color:var(--text-3);margin-top:.3rem}

/* 登录页 */
.auth-wrap{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:2rem;position:relative}
.auth-card{width:100%;max-width:420px;background:rgba(255,255,255,.95);backdrop-filter:blur(20px);
  border-radius:24px;padding:2.5rem;box-shadow:0 25px 50px -12px rgba(0,0,0,.15);border:1px solid rgba(255,255,255,.6)}
.auth-logo{text-align:center;margin-bottom:1.5rem}
.auth-title{font-size:1.6rem;font-weight:800;text-align:center;margin-bottom:.4rem}
.auth-sub{text-align:center;color:var(--text-2);font-size:.9rem;margin-bottom:1.8rem}
.auth-foot{text-align:center;margin-top:1.2rem;font-size:.88rem;color:var(--text-2)}

/* ========== 表格 ========== */
.table-wrap{overflow-x:auto}
table{width:100%;border-collapse:collapse;font-size:.9rem}
th,td{padding:.85rem 1rem;text-align:left;border-bottom:1px solid var(--border)}
th{background:var(--bg-2);font-weight:700;color:var(--text-2);font-size:.82rem;text-transform:uppercase;letter-spacing:.5px}
tr:hover td{background:var(--bg)}
.badge{display:inline-block;padding:.2rem .7rem;border-radius:20px;font-size:.78rem;font-weight:600}
.badge-green{background:#ecfdf5;color:var(--success)}
.badge-yellow{background:#fffbeb;color:var(--warning)}
.badge-red{background:#fef2f2;color:var(--danger)}
.badge-blue{background:#eff6ff;color:var(--info)}
.badge-purple{background:#f5f3ff;color:var(--primary)}

/* ========== 会员 ========== */
.plans-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:1.2rem}
.plan-card{background:var(--card);border-radius:var(--radius);padding:1.8rem;box-shadow:var(--shadow);
  border:2px solid var(--border);position:relative;transition:.3s;text-align:center}
.plan-card.featured{border-color:var(--primary);transform:scale(1.03)}
.plan-card.featured::after{content:"推荐";position:absolute;top:-12px;left:50%;transform:translateX(-50%);
  background:var(--gradient);color:#fff;padding:.25rem 1rem;border-radius:20px;font-size:.78rem;font-weight:700}
.plan-name{font-size:1.2rem;font-weight:800;margin-bottom:.5rem}
.plan-price{font-size:2.2rem;font-weight:800;color:var(--primary);margin:.8rem 0}
.plan-price small{font-size:.9rem;color:var(--text-3);font-weight:400}
.plan-desc{color:var(--text-2);font-size:.88rem;min-height:40px;margin-bottom:1rem}
.plan-benefits{text-align:left;margin-bottom:1.3rem}
.plan-benefits li{padding:.4rem 0;font-size:.88rem;color:var(--text-2);display:flex;gap:.5rem}
.plan-benefits li::before{content:"✓";color:var(--success);font-weight:700}
.plan-benefits li.off::before{content:"✕";color:var(--text-3)}
.plan-benefits li.off{color:var(--text-3)}

/* 权益矩阵 */
.benefit-table{overflow-x:auto}
.benefit-table table th,.benefit-table table td{text-align:center;white-space:nowrap}
.benefit-table table th:first-child,.benefit-table table td:first-child{text-align:left}
.toggle{position:relative;width:44px;height:24px;background:var(--border);border-radius:12px;transition:.2s;cursor:pointer;display:inline-block}
.toggle.on{background:var(--primary)}
.toggle::after{content:"";position:absolute;top:2px;left:2px;width:20px;height:20px;background:#fff;border-radius:50%;transition:.2s}
.toggle.on::after{left:22px}

/* ========== 进度环 ========== */
.progress-ring{transform:rotate(-90deg)}
.progress-ring circle{fill:none;stroke-width:8}
.progress-ring .bg{stroke:var(--border)}
.progress-ring .fg{stroke:var(--gradient);stroke-linecap:round;transition:stroke-dashoffset .8s}

/* ========== 进度条 ========== */
.progress{height:10px;background:var(--bg-2);border-radius:20px;overflow:hidden}
.progress-bar{height:100%;background:var(--gradient);border-radius:20px;transition:width .5s}

/* ========== 标签页 ========== */
.tabs{display:flex;gap:.3rem;border-bottom:2px solid var(--border);margin-bottom:1.5rem;overflow-x:auto}
.tab{padding:.7rem 1.2rem;font-weight:600;color:var(--text-2);border-bottom:2px solid transparent;
  margin-bottom:-2px;cursor:pointer;white-space:nowrap;transition:.2s}
.tab.active{color:var(--primary);border-bottom-color:var(--primary)}

/* ========== Toast ========== */
.toast{position:fixed;top:1.5rem;left:50%;transform:translateX(-50%);z-index:9999;
  padding:.9rem 1.5rem;border-radius:12px;color:#fff;font-weight:500;box-shadow:var(--shadow-lg);
  animation:slideDown .3s}
.toast.success{background:var(--success)}.toast.error{background:var(--danger)}.toast.info{background:var(--info)}
@keyframes slideDown{from{opacity:0;transform:translate(-50%,-20px)}to{opacity:1;transform:translate(-50%,0)}}

/* ========== 空状态 ========== */
.empty{text-align:center;padding:3rem 1rem;color:var(--text-3)}
.empty .emoji{font-size:3rem;margin-bottom:.8rem}

/* ========== 答题选项 ========== */
.options{display:grid;gap:.8rem}
.option{padding:1rem 1.2rem;border:2px solid var(--border);border-radius:14px;background:#fff;
  cursor:pointer;transition:.2s;font-weight:500}
.option:hover{border-color:var(--primary-light);background:var(--bg-2)}
.option.correct{border-color:var(--success);background:#ecfdf5;color:var(--success)}
.option.wrong{border-color:var(--danger);background:#fef2f2;color:var(--danger)}

/* ========== 词根图谱(3D) ========== */
.root-graph{position:relative;min-height:320px;display:flex;align-items:center;justify-content:center;perspective:1000px}
.root-center{padding:1rem 1.5rem;background:var(--gradient);color:#fff;border-radius:16px;
  font-weight:800;font-size:1.1rem;box-shadow:0 8px 24px rgba(99,102,241,.35);
  animation:floatY 4s ease-in-out infinite}
@keyframes floatY{0%,100%{transform:translateY(0)}50%{transform:translateY(-12px)}}
.root-node{position:absolute;padding:.5rem .9rem;background:var(--card);border-radius:10px;
  border:2px solid var(--primary-light);font-size:.85rem;font-weight:600;box-shadow:var(--shadow)}

/* ========== 后台布局 ========== */
.admin-layout{display:flex;min-height:100vh}
.admin-sidebar{width:240px;background:linear-gradient(180deg,#1e293b,#0f172a);color:#cbd5e1;
  padding:1.2rem 0;position:fixed;top:0;left:0;bottom:0;overflow-y:auto;z-index:50;transition:transform .3s}
.admin-sidebar .logo{color:#fff;padding:0 1.2rem 1.2rem;border-bottom:1px solid rgba(255,255,255,.1)}
.admin-side-item{display:flex;align-items:center;gap:.7rem;padding:.8rem 1.2rem;color:#cbd5e1;
  font-size:.92rem;transition:.2s;border-left:3px solid transparent}
.admin-side-item:hover{background:rgba(255,255,255,.05);color:#fff}
.admin-side-item.active{background:rgba(99,102,241,.15);color:#fff;border-left-color:var(--primary)}
.admin-main{margin-left:240px;flex:1;min-width:0}
.admin-topbar{background:#fff;border-bottom:1px solid var(--border);padding:.9rem 1.5rem;
  display:flex;align-items:center;justify-content:space-between;position:sticky;top:0;z-index:40}
.admin-content{padding:1.5rem}
.sidebar-toggle{display:none;background:var(--bg-2);border-radius:8px;padding:.4rem;font-size:1.2rem}

/* ========== 响应式 ========== */
@media (max-width:1023px){
  .admin-sidebar{transform:translateX(-100%)}
  .admin-sidebar.open{transform:translateX(0)}
  .admin-main{margin-left:0}
  .sidebar-toggle{display:block}
}
@media (max-width:767px){
  .nav-menu{display:none;position:absolute;top:60px;left:0;right:0;flex-direction:column;
    background:#fff;padding:1rem;box-shadow:var(--shadow-lg);gap:.3rem}
  .nav-menu.open{display:flex}
  .menu-toggle{display:flex}
  .tabbar{display:block}
  body{padding-bottom:64px}
  .page-title{font-size:1.3rem}
  .word-en{font-size:2rem}
  .stat-num{font-size:1.6rem}
  .stats{grid-template-columns:repeat(2,1fr)}
  .feedback-btn{padding:.7rem 1rem;font-size:.88rem}
  .plan-card.featured{transform:none}
}
@media (min-width:768px) and (max-width:1023px){
  .stats{grid-template-columns:repeat(3,1fr)}
}

/* ========== 动画工具 ========== */
.fade-in{animation:fadeIn .5s ease}
@keyframes fadeIn{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}
.spin{animation:spin 1s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}

/* ========== 滚动条 ========== */
::-webkit-scrollbar{width:8px;height:8px}
::-webkit-scrollbar-thumb{background:var(--border);border-radius:4px}
::-webkit-scrollbar-thumb:hover{background:var(--text-3)}

/* ========== 减少动效 ========== */
@media (prefers-reduced-motion:reduce){
  *{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
}

/* ========== 单词分类记忆法 ========== */
.cat-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(160px,1fr));gap:1rem}
.cat-card{background:var(--card);border-radius:var(--radius);padding:1.4rem 1.1rem;
  box-shadow:var(--shadow);border:1px solid var(--border);cursor:pointer;
  transition:all .3s;text-align:center;position:relative;overflow:hidden}
.cat-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.cat-card .cat-icon{font-size:2.4rem;line-height:1;margin-bottom:.5rem}
.cat-card .cat-name{font-weight:700;font-size:1rem;margin-bottom:.25rem}
.cat-card .cat-count{font-size:.8rem;color:var(--text-3)}
.cat-card .cat-bar{position:absolute;bottom:0;left:0;height:3px;width:100%;
  background:var(--cat-color,var(--primary))}
.cat-card:hover .cat-bar{height:4px}

.cat-detail-head{display:flex;align-items:center;gap:1rem;margin-bottom:1.2rem;flex-wrap:wrap}
.cat-detail-icon{width:56px;height:56px;border-radius:16px;display:flex;align-items:center;justify-content:center;
  font-size:2rem;background:var(--cat-color,#eef2ff);flex-shrink:0}
.cat-detail-title{font-size:1.4rem;font-weight:800}
.cat-detail-sub{color:var(--text-2);font-size:.9rem}

.word-list{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:.7rem}
.word-item{background:var(--card);border-radius:12px;padding:.8rem 1rem;
  border:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;gap:.8rem;
  transition:all .2s}
.word-item:hover{border-color:var(--primary-light);box-shadow:var(--shadow)}
.word-item .wi-main{min-width:0;flex:1}
.word-item .wi-en{font-weight:700;font-size:1rem;color:var(--text)}
.word-item .wi-cn{font-size:.82rem;color:var(--text-2);margin-top:2px}
.word-item .wi-tag{font-size:.7rem;padding:2px 8px;border-radius:999px;flex-shrink:0;white-space:nowrap}
.wi-tag.known{background:#dcfce7;color:#15803d}
.wi-tag.learning{background:#fef9c3;color:#a16207}
.wi-tag.new{background:#f1f5f9;color:#64748b}
.wi-tag.library{background:#ede9fe;color:#6d28d9}

.cat-filter-bar{display:flex;gap:.5rem;flex-wrap:wrap;margin-bottom:1rem;align-items:center}
.cat-search{flex:1;min-width:200px;padding:.6rem 1rem;border-radius:10px;border:1px solid var(--border);
  background:#fff;font-size:.9rem}
.cat-search:focus{outline:none;border-color:var(--primary)}