*{margin:0;padding:0;box-sizing:border-box}
:root{--primary:#4f46e5;--primary-light:#e0e7ff;--green:#16a34a;--red:#dc2626;--yellow:#f59e0b;--bg:#f8fafc;--card-bg:#fff;--text:#1e293b;--text-light:#64748b;--border:#e2e8f0;--radius:12px;--shadow:0 1px 3px rgba(0,0,0,.06)}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;background:var(--bg);color:var(--text);line-height:1.6}

/* 登录 */
.login-overlay{position:fixed;inset:0;background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);display:flex;flex-direction:column;align-items:center;justify-content:center;z-index:1000}
.login-box{background:#fff;border-radius:16px;padding:36px 32px;width:400px;max-width:90vw;max-height:90vh;overflow-y:auto;box-shadow:0 20px 60px rgba(0,0,0,.2)}
.login-header{text-align:center;margin-bottom:24px}
.login-logo{font-size:48px;margin-bottom:8px}
.login-header h2{font-size:20px;font-weight:700}
.login-header p{font-size:13px;color:var(--text-light);margin-top:4px}
.login-error{background:#fef2f2;color:var(--red);padding:10px 14px;border-radius:8px;font-size:13px;margin-bottom:16px;border:1px solid #fecaca}
.login-success{background:#f0fdf4;color:var(--green);padding:10px 14px;border-radius:8px;font-size:13px;margin-bottom:16px;border:1px solid #bbf7d0}
.login-btn{width:100%;justify-content:center;padding:12px;font-size:15px;margin-top:8px}
.login-footer{text-align:center;margin-top:20px;font-size:13px;color:var(--text-light)}
.login-footer a{color:var(--primary);text-decoration:none;font-weight:600;margin-left:4px}
.login-footer a:hover{text-decoration:underline}

/* 布局 */
.app{display:flex;min-height:100vh}
.sidebar{width:240px;background:var(--card-bg);border-right:1px solid var(--border);padding:20px 16px;display:flex;flex-direction:column;gap:8px;position:fixed;top:0;left:0;bottom:0;z-index:10}
.logo{font-size:18px;font-weight:700;padding:8px 12px;margin-bottom:12px}
.nav-item{display:flex;align-items:center;justify-content:space-between;padding:10px 14px;border-radius:8px;color:var(--text);text-decoration:none;font-size:14px;transition:all .15s}
.nav-item:hover{background:var(--bg)}
.nav-item.active{background:var(--primary-light);color:var(--primary);font-weight:600}
.badge{background:var(--red);color:#fff;font-size:12px;padding:2px 8px;border-radius:10px;min-width:22px;text-align:center}
.sidebar-footer{margin-top:auto;padding-top:16px;border-top:1px solid var(--border)}
.sidebar-footer label{font-size:12px;color:var(--text-light);display:block;margin-bottom:6px}
.sidebar-footer select{width:100%;padding:8px 10px;border:1px solid var(--border);border-radius:6px;font-size:13px;background:#fff}
.user-info{display:flex;align-items:center;justify-content:space-between;margin-top:12px;padding-top:12px;border-top:1px solid var(--border);font-size:13px}
.logout-link{color:var(--red);text-decoration:none;font-size:12px;font-weight:500}
.logout-link:hover{text-decoration:underline}

/* 主内容 */
.main{margin-left:240px;flex:1;padding:28px 36px;max-width:900px}
.page-header{margin-bottom:24px}
.page-header h1{font-size:24px;font-weight:700}
.page-header p{color:var(--text-light);margin-top:4px}

/* 列表 */
.item-list{display:flex;flex-direction:column;gap:12px}
.item-card{background:var(--card-bg);border:1px solid var(--border);border-radius:var(--radius);padding:16px 20px;box-shadow:var(--shadow);cursor:pointer;transition:all .15s}
.item-card:hover{border-color:var(--primary);transform:translateY(-1px)}
.item-card .title{font-size:15px;font-weight:600;margin-bottom:4px}
.item-card .meta{display:flex;gap:14px;font-size:12px;color:var(--text-light);margin-top:6px;flex-wrap:wrap}
.tag{background:var(--primary-light);color:var(--primary);padding:2px 8px;border-radius:4px;font-weight:500;font-size:12px}
.due{color:var(--red);font-weight:600}
.ok{color:var(--green)}

/* 复习 */
.review-card{background:var(--card-bg);border:2px solid var(--border);border-radius:var(--radius);padding:32px;text-align:center;box-shadow:var(--shadow)}
.review-card .item-title{font-size:22px;font-weight:700;margin-bottom:8px}
.review-card .item-content{font-size:16px;color:var(--green);margin-bottom:28px;padding:20px;background:#f0fdf4;border-radius:10px;display:none;text-align:left;line-height:1.8;white-space:pre-wrap}
.review-card .item-content.show{display:block}

/* 按钮 */
.btn{display:inline-flex;align-items:center;gap:6px;padding:10px 20px;border:none;border-radius:8px;font-size:14px;font-weight:600;cursor:pointer;transition:all .15s}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{opacity:.9}
.btn-outline{background:#fff;color:var(--primary);border:1px solid var(--primary)}
.btn-outline:hover{background:var(--primary-light)}
.btn-danger{background:var(--red);color:#fff}
.btn-sm{padding:6px 12px;font-size:12px}
.rating-buttons{display:flex;gap:10px;flex-wrap:wrap;justify-content:center;margin-top:24px}
.rating-btn{width:52px;height:52px;border-radius:50%;border:2px solid var(--border);background:#fff;font-size:18px;font-weight:700;cursor:pointer;transition:all .15s;display:flex;flex-direction:column;align-items:center;justify-content:center}
.rating-btn small{font-size:9px;font-weight:400;color:var(--text-light)}
.rating-btn:hover{border-color:var(--primary);transform:scale(1.1)}
.rating-btn.q-0:hover{border-color:var(--red);background:#fef2f2}
.rating-btn.q-1:hover,.rating-btn.q-2:hover{border-color:var(--yellow);background:#fffbeb}
.rating-btn.q-3:hover,.rating-btn.q-4:hover,.rating-btn.q-5:hover{border-color:var(--green);background:#f0fdf4}

/* 空状态 */
.empty{padding:60px 20px;text-align:center;color:var(--text-light)}
.empty .emoji{font-size:48px;margin-bottom:12px}
.empty h3{font-size:18px;margin-bottom:6px;color:var(--text)}

/* 表单 */
.form-group{margin-bottom:16px}
.form-group label{display:block;font-weight:600;font-size:13px;margin-bottom:6px}
.form-group input,.form-group textarea,.form-group select{width:100%;padding:10px 14px;border:1px solid var(--border);border-radius:8px;font-size:14px;font-family:inherit}
.form-group textarea{resize:vertical;min-height:80px}
.form-group input:focus,.form-group textarea:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px var(--primary-light)}
.form-actions{display:flex;gap:10px;margin-top:20px}

/* 统计 */
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-bottom:24px}
.stat-card{background:var(--card-bg);border:1px solid var(--border);border-radius:var(--radius);padding:18px;text-align:center;box-shadow:var(--shadow)}
.stat-card .value{font-size:32px;font-weight:800;color:var(--primary)}
.stat-card .label{font-size:12px;color:var(--text-light);margin-top:4px}
.chart-box{background:var(--card-bg);border:1px solid var(--border);border-radius:var(--radius);padding:20px;margin-bottom:16px;box-shadow:var(--shadow)}
.chart-box h3{font-size:14px;margin-bottom:12px}

/* 工具栏 */
.toolbar{display:flex;gap:10px;margin-bottom:20px;flex-wrap:wrap}
.toolbar input{flex:1;min-width:200px;padding:10px 14px;border:1px solid var(--border);border-radius:8px;font-size:14px}
.toolbar input:focus{outline:none;border-color:var(--primary)}

/* 弹窗 */
.modal{position:fixed;inset:0;background:rgba(0,0,0,.4);display:flex;align-items:center;justify-content:center;z-index:999}
.modal-content{background:#fff;border-radius:12px;padding:24px;width:360px;max-width:90vw}
.modal-content h3{margin-bottom:16px}

/* 表格 */
table{width:100%;border-collapse:collapse;background:var(--card-bg);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow)}
th,td{padding:12px 16px;text-align:left;font-size:13px;border-bottom:1px solid var(--border)}
th{background:#f1f5f9;font-weight:600}
.role-badge{font-size:11px;padding:2px 8px;border-radius:4px;font-weight:600}
.role-badge.admin{background:#fef3c7;color:#92400e}
.role-badge.user{background:var(--primary-light);color:var(--primary)}
.verified{color:var(--green)}
.unverified{color:var(--red)}
.role-tag{font-size:11px;padding:1px 6px;border-radius:4px;font-weight:600}
.role-tag.admin{background:#fef3c7;color:#92400e}

/* Toast */
.toast{position:fixed;bottom:24px;right:24px;background:#1e293b;color:#fff;padding:12px 20px;border-radius:8px;font-size:13px;z-index:999;opacity:0;transform:translateY(10px);transition:all .3s;pointer-events:none}
.toast.show{opacity:1;transform:translateY(0)}

@media(max-width:768px){
.sidebar{width:180px}
.main{margin-left:180px;padding:16px}
.stats-grid{grid-template-columns:repeat(2,1fr)}
}