:root{
  --bg:#f4f6fb; --card:#ffffff; --border:#e5e9f2; --text:#1f2937; --muted:#6b7280;
  --primary:#2f6bff; --primary-dark:#1f4fd8; --danger:#e5484d; --success:#16a34a;
  --warn:#f59e0b; --radius:14px; --shadow:0 2px 14px rgba(31,41,55,.06);
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{
  font-family:"PingFang SC","Microsoft YaHei","Segoe UI",system-ui,sans-serif;
  background:var(--bg); color:var(--text); font-size:15px; line-height:1.6;
}
a{color:var(--primary);text-decoration:none}

/* 顶部导航 */
.topbar{
  position:sticky; top:0; z-index:50; display:flex; align-items:center; justify-content:space-between;
  padding:0 28px; height:64px; background:var(--card); border-bottom:1px solid var(--border); box-shadow:var(--shadow);
}
.brand{display:flex;align-items:center;gap:12px}
.logo{font-size:26px}
.brand-text h1{font-size:17px;font-weight:700}
.brand-text p{font-size:12px;color:var(--muted)}
.nav{display:flex;gap:6px}
.nav-btn{
  border:1px solid transparent;background:transparent;padding:8px 16px;border-radius:10px;
  font-size:14px;cursor:pointer;color:var(--muted);transition:.15s;
}
.nav-btn:hover{background:#f0f4ff;color:var(--primary)}
.nav-btn.active{background:#eaf0ff;color:var(--primary);font-weight:600}

main{max-width:1200px;margin:0 auto;padding:28px 20px 60px}
.view{display:none}
.view.active{display:block;animation:fade .25s}
@keyframes fade{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}

/* 首页 hero */
.hero{background:linear-gradient(135deg,#2f6bff,#5b8cff);color:#fff;border-radius:var(--radius);padding:30px 32px;margin-bottom:28px;box-shadow:0 8px 24px rgba(47,107,255,.25)}
.hero h2{font-size:24px;margin-bottom:8px}
.hero p{opacity:.92;max-width:760px}
.hero-badges{display:flex;flex-wrap:wrap;gap:10px;margin-top:18px}
.badge{background:rgba(255,255,255,.18);padding:6px 14px;border-radius:20px;font-size:13px}

.section-title{display:flex;align-items:baseline;gap:12px;margin-bottom:14px}
.section-title h3{font-size:18px}
.section-title span{font-size:13px;color:var(--muted)}

.paper-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px}
.paper-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow);transition:.15s;position:relative}
.paper-card:hover{transform:translateY(-3px);box-shadow:0 8px 22px rgba(31,41,55,.1);border-color:#cdd8ff}
.paper-card .tag{position:absolute;top:14px;right:14px;font-size:12px;padding:3px 10px;border-radius:12px}
.tag.sim{background:#eaf0ff;color:var(--primary)}
.tag.pred{background:#fff1e0;color:#d97706}
.tag.zhen{background:#fdeaea;color:#c81e1e}
.paper-card h4{font-size:16px;margin-bottom:6px;padding-right:56px}
.paper-card .desc{font-size:13px;color:var(--muted);min-height:40px}
.paper-card .meta{display:flex;gap:14px;margin:12px 0;font-size:12.5px;color:var(--muted)}
.paper-card .actions{display:flex;gap:8px;flex-wrap:wrap}
.btn{
  border:none;background:var(--primary);color:#fff;padding:9px 18px;border-radius:10px;
  font-size:14px;cursor:pointer;transition:.15s;font-weight:600;
}
.btn:hover{background:var(--primary-dark)}
.btn.ghost{background:#f0f4ff;color:var(--primary)}
.btn.ghost:hover{background:#e2eaff}
.btn.danger{background:var(--danger)}
.btn.danger:hover{background:#c73a3f}
.btn.sm{padding:6px 13px;font-size:13px}
.btn:disabled{opacity:.45;cursor:not-allowed}

/* 面板 */
.panel{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:26px;box-shadow:var(--shadow)}
.panel.narrow{max-width:560px}
.panel h2{font-size:20px;margin-bottom:8px}
.muted{color:var(--muted);font-size:13.5px}

/* 设置表单 */
.panel label{display:block;margin:16px 0 6px;font-size:13.5px;font-weight:600}
.panel input{width:100%;padding:10px 12px;border:1px solid var(--border);border-radius:10px;font-size:14px}
.panel input:focus{outline:none;border-color:var(--primary)}

/* 考试界面 */
.exam-header{
  position:sticky;top:64px;z-index:40;display:flex;align-items:center;justify-content:space-between;
  background:var(--card);border:1px solid var(--border);border-bottom:none;border-radius:var(--radius) var(--radius) 0 0;
  padding:16px 22px;box-shadow:var(--shadow);
}
.exam-info h2{font-size:17px}
.exam-info span{font-size:13px;color:var(--muted)}
.exam-tools{display:flex;align-items:center;gap:12px}
.timer{font-family:"SF Mono",Consolas,monospace;font-size:20px;font-weight:700;color:var(--primary);background:#eaf0ff;padding:6px 14px;border-radius:10px;min-width:96px;text-align:center}
.timer.warn{color:var(--danger);background:#fdeaea;animation:blink 1s infinite}
@keyframes blink{50%{opacity:.5}}

.exam-body{display:grid;grid-template-columns:1fr 300px;gap:0;background:var(--card);border:1px solid var(--border);border-radius:0 0 var(--radius) var(--radius);box-shadow:var(--shadow);min-height:70vh}
.question-area{padding:26px 30px;border-right:1px solid var(--border)}
.answer-sheet{padding:18px;max-height:calc(100vh - 200px);overflow:auto;position:sticky;top:140px}

.q-block{margin-bottom:28px}
.q-stem{font-size:15.5px;font-weight:600;margin-bottom:16px}
.q-stem .q-no{color:var(--primary);margin-right:6px}
.opt{display:flex;align-items:flex-start;gap:12px;padding:11px 14px;border:1px solid var(--border);border-radius:10px;margin-bottom:10px;cursor:pointer;transition:.12s}
.opt:hover{border-color:#b9c8ff;background:#f8faff}
.opt .key{font-weight:700;color:var(--muted);flex-shrink:0}
.opt.selected{border-color:var(--primary);background:#eef3ff}
.opt.selected .key{color:var(--primary)}

.case-box{background:#f8faff;border:1px solid #e3ebff;border-radius:10px;padding:18px;margin-bottom:18px;font-size:14.5px}
.case-diagram{background:#fff;border:1px solid var(--border);border-radius:10px;padding:16px;margin-bottom:18px;overflow-x:auto}
.case-diagram .fig-title{font-size:13px;font-weight:700;color:var(--primary);margin-bottom:10px}
.case-diagram table{width:100%;border-collapse:collapse;font-size:13px;margin:8px 0}
.case-diagram th,.case-diagram td{border:1px solid var(--border);padding:6px 10px;text-align:center}
.case-diagram th{background:#f0f4ff;font-weight:600}
.case-diagram tr.cp-row td{background:#fff3f0}
.case-diagram .note{font-size:12px;color:var(--muted);margin-top:6px}
.case-diagram svg{max-width:100%;height:auto;display:block;margin:0 auto}
.case-box b{color:var(--primary)}
.sub-q{margin-bottom:20px}
.sub-q .sq{font-weight:600;margin-bottom:8px}
.sub-q textarea{width:100%;min-height:110px;padding:12px;border:1px solid var(--border);border-radius:10px;font-size:14px;resize:vertical;font-family:inherit;line-height:1.7}
.sub-q textarea:focus{outline:none;border-color:var(--primary)}
.sub-q .pts{font-size:12px;color:var(--muted);margin-top:4px}

.nav-row{display:flex;justify-content:space-between;margin-top:8px;gap:12px}

/* 答题卡 */
.sheet-title{font-size:14px;font-weight:700;margin-bottom:10px;text-align:center}
.sheet-legend{display:flex;gap:10px;justify-content:center;font-size:11.5px;color:var(--muted);margin-bottom:12px}
.legend-dot{display:inline-block;width:10px;height:10px;border-radius:3px;margin-right:4px;vertical-align:middle}
.sheet-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:7px}
.cell{height:34px;border:1px solid var(--border);border-radius:7px;display:flex;align-items:center;justify-content:center;font-size:13px;cursor:pointer;font-weight:600;transition:.12s}
.cell.answered{background:var(--primary);color:#fff;border-color:var(--primary)}
.cell.marked{outline:2px solid var(--warn);outline-offset:1px}
.cell.current{outline:2px solid var(--text);outline-offset:1px}

/* 报告 */
.score-hero{display:flex;gap:24px;flex-wrap:wrap;background:linear-gradient(135deg,#2f6bff,#5b8cff);color:#fff;border-radius:var(--radius);padding:28px 30px;margin-bottom:22px;box-shadow:0 8px 24px rgba(47,107,255,.22)}
.score-hero .score-big{font-size:56px;font-weight:800;line-height:1}
.score-hero .pass-tag{font-size:14px;padding:4px 14px;border-radius:16px;background:rgba(255,255,255,.2);display:inline-block;margin-top:10px}
.score-hero .kv{font-size:14px;opacity:.95}
.score-block{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow);margin-bottom:18px}
.score-block h3{font-size:16px;margin-bottom:14px;border-left:4px solid var(--primary);padding-left:10px}
.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:18px}
@media(max-width:860px){.grid-2{grid-template-columns:1fr}.exam-body{grid-template-columns:1fr}.answer-sheet{position:static;max-height:none;border-top:1px solid var(--border)}}

.bar-row{display:flex;align-items:center;gap:10px;margin-bottom:10px;font-size:13px}
.bar-row .lbl{width:120px;flex-shrink:0;text-align:right}
.bar-track{flex:1;height:14px;background:#eef1f7;border-radius:8px;overflow:hidden}
.bar-fill{height:100%;border-radius:8px;transition:.3s}
.bar-row .val{width:64px;font-weight:600;flex-shrink:0}

.erq{border:1px solid var(--border);border-radius:10px;padding:14px 16px;margin-bottom:12px;background:#fbfcfe}
.erq .erq-head{display:flex;justify-content:space-between;gap:12px;margin-bottom:8px;font-size:13.5px}
.erq .wrong{color:var(--danger);font-weight:700}
.erq .right{color:var(--success);font-weight:700}
.erq .stem{font-size:14px;margin-bottom:6px}
.erq .exp{font-size:13px;color:var(--muted);background:#f4f6fb;padding:10px;border-radius:8px}
.chip{display:inline-block;font-size:12px;padding:2px 10px;border-radius:12px;background:#eef1f7;color:var(--muted);margin-right:6px}
.chip.hot{background:#fff1e0;color:#d97706}
.chip.must{background:#fdeaea;color:var(--danger)}

table{width:100%;border-collapse:collapse;font-size:13.5px}
th,td{border:1px solid var(--border);padding:9px 12px;text-align:left}
th{background:#f4f6fb;font-weight:700}
td.c,th.c{text-align:center}
.adv-item{display:flex;gap:12px;padding:12px 0;border-bottom:1px dashed var(--border)}
.adv-item:last-child{border-bottom:none}
.adv-ico{font-size:20px}

/* 弹窗 */
.modal-mask{position:fixed;inset:0;background:rgba(15,23,42,.45);display:none;align-items:center;justify-content:center;z-index:100}
.modal-mask.show{display:flex}
.modal{background:#fff;border-radius:16px;padding:28px;width:420px;max-width:92vw;box-shadow:0 20px 60px rgba(0,0,0,.2)}
.modal h3{font-size:18px;margin-bottom:10px}
.modal p{color:var(--muted);font-size:14px;margin-bottom:20px}
.modal-actions{display:flex;justify-content:flex-end;gap:10px}

.empty{padding:40px;text-align:center;color:var(--muted)}
.spin{display:inline-block;width:16px;height:16px;border:2px solid #fff;border-top-color:transparent;border-radius:50%;animation:spin .7s linear infinite;vertical-align:middle;margin-right:8px}
@keyframes spin{to{transform:rotate(360deg)}}

/* 用户区 */
.user-box{display:flex;align-items:center;gap:10px}
.user-label{font-size:13.5px;color:var(--text);font-weight:600}

/* 登录页 */
.login-wrap{max-width:440px;margin:8vh auto 0;padding:0 20px}
.login-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:36px 34px;box-shadow:var(--shadow);text-align:center}
.login-logo{font-size:44px;margin-bottom:10px}
.login-card h2{font-size:20px;margin-bottom:6px}
.login-form{text-align:left;margin-top:22px}
.login-form label{display:block;margin:14px 0 6px;font-size:13.5px;font-weight:600}
.login-form input{width:100%;padding:11px 13px;border:1px solid var(--border);border-radius:10px;font-size:15px}
.login-form input:focus{outline:none;border-color:var(--primary)}
.login-row{display:flex;gap:10px}
.login-row input{flex:1}
.login-row .btn{flex-shrink:0;white-space:nowrap}
.login-error{min-height:20px;margin-top:10px;font-size:13px;color:var(--danger)}
.login-submit{width:100%;margin-top:14px;padding:12px;font-size:15px}
.login-tip{margin-top:14px;font-size:12px}

/* 错题本 */
.wrongbook-head{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px;margin-bottom:16px}
.wrongbook-tools{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.wb-select{padding:8px 12px;border:1px solid var(--border);border-radius:10px;font-size:13.5px;background:#fff}
.wrongbook-stats{margin-bottom:16px}
.wb-stat-box{background:#f0f4ff;border:1px solid #dbe4ff;border-radius:10px;padding:12px 16px;font-size:14px}
.wb-stat-box b{color:var(--primary);font-size:17px}
.wq-card{border:1px solid var(--border);border-radius:12px;padding:18px 20px;margin-bottom:14px;background:#fff;box-shadow:var(--shadow)}
.wq-head{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:10px;font-size:12.5px}
.wq-paper{color:var(--muted)}
.wq-time{color:var(--muted);margin-left:auto}
.wq-stem{font-size:15px;font-weight:600;margin-bottom:10px}
.wq-opts{margin-bottom:10px}
.wq-opt{font-size:13.5px;color:#4b5563;padding:3px 0}
.wq-ans{display:flex;gap:16px;margin-bottom:8px;font-size:14px}
.wq-ans .wrong{color:var(--danger);font-weight:700}
.wq-ans .right{color:var(--success);font-weight:700}
.wq-exp{font-size:13px;color:var(--muted);background:#f4f6fb;padding:10px 12px;border-radius:8px;margin-bottom:8px}
.wq-note{font-size:13px;background:#fff9ec;border:1px solid #fdeecb;color:#b45309;padding:10px 12px;border-radius:8px;margin-bottom:10px}
.wq-actions{display:flex;gap:10px;margin-top:6px}

/* AI 错题分析 */
.wq-ai{margin-top:10px;padding:12px 14px;background:#f6f9ff;border:1px solid #dbe6ff;border-radius:10px;font-size:13.5px}
.wq-ai-item{display:flex;gap:8px;margin-bottom:8px;line-height:1.7}
.wq-ai-item:last-child{margin-bottom:0}
.wq-ai-tag{flex-shrink:0;font-weight:700;color:var(--primary)}
.wq-ai-item.wq-memory{background:#fff9ec;border:1px dashed #f0c76a;border-radius:8px;padding:8px 10px;margin-bottom:0}
.wq-ai-item.wq-memory .wq-ai-tag{color:#d97706}
.wq-ai-pending{display:flex;align-items:center;justify-content:space-between;gap:10px;color:var(--muted)}

/* 历史答题详情弹窗 */
.modal-lg{width:760px;max-width:94vw;padding:0;overflow:hidden;display:flex;flex-direction:column;max-height:88vh}
.modal-head{display:flex;align-items:center;justify-content:space-between;padding:18px 22px;border-bottom:1px solid var(--border);flex-shrink:0}
.modal-head h3{margin:0;font-size:17px}
.modal-close{border:none;background:none;font-size:20px;cursor:pointer;color:var(--muted);line-height:1;padding:4px 10px;border-radius:8px}
.modal-close:hover{background:#f0f4ff;color:var(--primary)}
.modal-body{padding:18px 22px;overflow-y:auto}
.detail-summary{font-size:14px;color:#4b5563;margin-bottom:12px;padding:10px 14px;background:#f6f9ff;border:1px solid #dbe6ff;border-radius:10px}
.d-card{border:1px solid var(--border);border-radius:12px;padding:16px 18px;margin-bottom:12px;background:#fff;box-shadow:var(--shadow)}
.d-card.d-wrong{border-left:4px solid var(--danger)}
.d-head{display:flex;align-items:center;gap:8px;margin-bottom:10px;flex-wrap:wrap}
.d-no{display:inline-flex;align-items:center;justify-content:center;min-width:28px;height:28px;border-radius:8px;background:var(--primary);color:#fff;font-weight:700;font-size:13px;padding:0 8px}
.d-stem{font-size:14.5px;font-weight:600;line-height:1.6;margin-bottom:8px}
.d-opts{margin-bottom:8px}
.d-opt{font-size:13.5px;color:#4b5563;padding:3px 6px;border-radius:6px}
.d-opt.opt-right{background:#e6f7ec;color:#16a34a;font-weight:600}
.d-opt.opt-wrong{background:#fdeaea;color:#c81e1e;font-weight:600}
.d-ans{display:flex;gap:18px;font-size:13.5px;margin-bottom:6px;flex-wrap:wrap}
.d-ans .wrong{color:var(--danger);font-weight:700}
.d-ans .right{color:var(--success);font-weight:700}
.d-exp{font-size:13px;color:var(--muted);background:#f4f6fb;padding:8px 12px;border-radius:8px;line-height:1.6;margin-top:6px}
.d-text{font-size:13.5px;color:#374151;background:#fafafa;border:1px solid var(--border);border-radius:8px;padding:8px 12px;margin-top:4px;white-space:pre-wrap;line-height:1.6}
.chip.ok{background:#e6f7ec;color:#16a34a}
.chip.bad{background:#fdeaea;color:#c81e1e}
.btn.del{color:var(--danger)}
.btn.del:hover{background:#fdeaea}