:root{
  --navy:#102a43; --navy2:#173f63; --blue:#1f6fb2; --blue2:#2b87d1;
  --bg:#f3f7fb; --card:#ffffff; --ink:#17212f; --muted:#6b7c90;
  --line:#dfe8f1; --green:#1e8449; --red:#c0392b; --amber:#b7791f;
  --radius:16px; --shadow:0 10px 30px rgba(16,42,67,.08);
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  font-family:"Microsoft YaHei","PingFang SC","Noto Sans CJK SC",system-ui,sans-serif;
  background:var(--bg);color:var(--ink);font-size:15px;line-height:1.6;
}
button,input,textarea{font:inherit}
button{cursor:pointer}
.hidden{display:none !important}
a{color:var(--blue);text-decoration:none}
.muted{color:var(--muted)}
.hint{color:var(--muted);font-size:12.5px;margin:10px 0 0}
.msg{color:var(--red);min-height:20px;margin:10px 0 0}
.hidden{display:none!important}

/* 登录 */
.auth-wrap{
  min-height:100vh;display:flex;align-items:center;justify-content:center;
  background:
    radial-gradient(800px 400px at 10% 0%,rgba(43,135,209,.30),transparent 60%),
    radial-gradient(600px 400px at 95% 100%,rgba(43,135,209,.18),transparent 60%),
    linear-gradient(135deg,#0d2137,#153b5c 60%,#0e2b47);
  padding:24px;
}
.auth-card{
  width:min(460px,100%);background:rgba(255,255,255,.98);border-radius:22px;
  padding:34px 34px 28px;box-shadow:0 30px 70px rgba(0,0,0,.28)
}
.brand{display:flex;align-items:center;gap:12px}
.brand.big{gap:16px;margin-bottom:26px}
.brand-mark{
  width:48px;height:48px;border-radius:14px;display:flex;align-items:center;justify-content:center;
  background:linear-gradient(135deg,var(--blue2),#0f4f86);color:#fff;font-weight:800;letter-spacing:.5px;
  box-shadow:0 6px 16px rgba(31,111,178,.35)
}
.brand.big .brand-mark{width:54px;height:54px;font-size:18px}
.brand h1{font-size:22px;margin:0;letter-spacing:.5px}
.brand p{margin:2px 0 0;color:var(--muted);font-size:13px}
.brand strong{display:block;font-size:16px;line-height:1.25}
.brand span{color:var(--muted);font-size:12px}
.auth-tabs{display:flex;gap:8px;border-bottom:1px solid var(--line);margin-bottom:20px}
.tab{background:none;border:0;padding:10px 2px;margin-right:18px;color:var(--muted);font-weight:600;border-bottom:2px solid transparent}
.tab.active{color:var(--blue);border-bottom-color:var(--blue)}
.auth-form label{display:block;margin:14px 0;font-size:13px;color:#39506a;font-weight:600}
.auth-form input{
  width:100%;margin-top:7px;padding:12px 13px;border:1px solid var(--line);border-radius:10px;
  background:#f8fbfe;color:var(--ink);outline:none
}
.auth-form input:focus{border-color:var(--blue);box-shadow:0 0 0 3px rgba(31,111,178,.12);background:#fff}
.primary{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;border:0;border-radius:10px;
  padding:11px 20px;background:linear-gradient(135deg,var(--blue),#15598f);color:#fff;font-weight:700;
  box-shadow:0 6px 16px rgba(31,111,178,.28)
}
.primary:disabled{opacity:.55;cursor:not-allowed;box-shadow:none}
.auth-form .primary{width:100%;margin-top:8px}
.ghost{background:#fff;border:1px solid var(--line);color:var(--ink);border-radius:10px;padding:9px 14px}
.ghost:hover{border-color:#b9cde0;background:#f7fbff}
.link{background:none;border:0;color:var(--blue);padding:0}
.pill{border:1px solid #cfe1f3;background:#eef7ff;color:#15598f;border-radius:999px;padding:7px 14px;font-weight:700}

/* 主界面 */
.app{min-height:100vh}
.topbar{
  height:66px;background:#fff;border-bottom:1px solid var(--line);display:flex;align-items:center;
  justify-content:space-between;padding:0 22px;position:sticky;top:0;z-index:10
}
.top-actions{display:flex;align-items:center;gap:10px}
.user-name{color:var(--muted);font-size:13px}
.demo-banner{background:#fff4d6;border-bottom:1px solid #f0d58a;color:#7a5a00;padding:10px 22px;font-size:13px;text-align:center}
.layout{display:grid;grid-template-columns:260px minmax(0,1fr);gap:0;min-height:calc(100vh - 66px)}
.sidebar{
  background:#fff;border-right:1px solid var(--line);padding:18px 14px;position:sticky;top:66px;
  height:calc(100vh - 66px);overflow:auto
}
.new-btn{width:100%;border:0;border-radius:12px;background:linear-gradient(135deg,var(--blue),#15598f);color:#fff;padding:12px;font-weight:800;box-shadow:0 8px 18px rgba(31,111,178,.22)}
.side-title{font-size:12px;color:var(--muted);margin:20px 6px 8px;letter-spacing:.08em}
.history{display:flex;flex-direction:column;gap:7px}
.history-item{border:1px solid transparent;background:#f8fbfe;border-radius:11px;padding:10px 11px;text-align:left;width:100%}
.history-item:hover{border-color:#cfe1f3;background:#f2f9ff}
.history-item.active{border-color:var(--blue);background:#edf7ff}
.history-title{font-size:13px;color:var(--ink);display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;white-space:pre-wrap}
.history-meta{display:flex;gap:6px;align-items:center;color:var(--muted);font-size:11.5px;margin-top:4px}
.dot{width:7px;height:7px;border-radius:50%;background:#aab8c6}
.dot.done{background:var(--green)}.dot.error{background:var(--red)}.dot.running{background:var(--amber)}
.main{padding:26px clamp(18px,4vw,54px) 60px;max-width:1180px;width:100%;margin:0 auto}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
.composer{padding:28px 30px}
.composer-head{display:flex;justify-content:space-between;gap:18px;align-items:flex-start}
.eyebrow{margin:0 0 6px;color:var(--blue);font-size:12px;font-weight:800;letter-spacing:.08em}
.composer h1{margin:0;font-size:25px;letter-spacing:.3px}
.subject-chip{font-size:12px;color:#4b647c;background:#f1f7fd;border:1px solid #dbe9f6;border-radius:999px;padding:7px 12px;white-space:nowrap}
textarea{
  width:100%;margin:20px 0 14px;padding:16px;border:1px solid var(--line);border-radius:12px;
  background:#fbfdff;resize:vertical;min-height:220px;outline:none;line-height:1.8
}
textarea:focus{border-color:var(--blue);box-shadow:0 0 0 3px rgba(31,111,178,.1);background:#fff}
.upload-row{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.upload-btn{border:1px dashed #b9cde0;border-radius:10px;padding:9px 14px;color:#31506d;background:#f9fcff;cursor:pointer}
.image-preview{margin-top:12px;border:1px solid var(--line);border-radius:12px;padding:8px;background:#f8fbfe}
.image-preview img{max-width:100%;max-height:280px;display:block;margin:auto;border-radius:8px}
.composer-foot{display:flex;justify-content:space-between;align-items:center;margin-top:18px;gap:12px}
.composer-foot .primary{padding:13px 24px;font-size:16px}

/* 结果 */
.result{display:flex;flex-direction:column;gap:16px;margin-top:18px}
.result-head{display:flex;justify-content:space-between;gap:16px;padding:20px 24px}
.result-head h2{margin:0;font-size:19px;line-height:1.5;white-space:pre-wrap}
.result-actions{display:flex;gap:8px;align-items:center;flex-shrink:0}
.progress{display:flex;gap:14px;align-items:center;padding:20px 24px}
.spinner{width:24px;height:24px;border:3px solid #dce9f5;border-top-color:var(--blue);border-radius:50%;animation:spin 1s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.error{border-left:4px solid var(--red);padding:18px 22px;color:#7f1d1d;background:#fff7f7}
.answer-line{display:flex;align-items:center;gap:12px;padding:22px 24px;border-bottom:1px solid var(--line)}
.answer-label{color:var(--muted);font-size:13px}
.answer-value{font-size:30px;font-weight:900;color:var(--green);letter-spacing:2px}
.explanations{padding:6px 24px 10px}
.exp-row{display:grid;grid-template-columns:56px 100px 1fr;gap:12px;padding:14px 0;border-bottom:1px dashed #e7eef5;align-items:start}
.exp-row:last-child{border-bottom:0}
.exp-opt{font-weight:900;font-size:16px;color:var(--navy)}
.verdict{display:inline-block;font-size:12px;font-weight:800;border-radius:999px;padding:4px 9px;width:max-content}
.verdict.right{color:#12633a;background:#e8f7ee}
.verdict.wrong{color:#9b2c2c;background:#fdeeee}
.verdict.na{color:#6b5b16;background:#fdf6e3}
.exp-reason{color:#33465a;font-size:14px}
.pages{padding:0 24px 20px;color:var(--muted);font-size:12.5px}
.pages span{display:inline-block;background:#f3f8fd;border:1px solid #e0ecf7;border-radius:7px;padding:4px 8px;margin:4px 6px 0 0}
.image-card{padding:10px}
.image-card img{width:100%;display:block;border-radius:10px}

/* 弹窗 */
.modal{position:fixed;inset:0;background:rgba(8,22,36,.55);display:flex;align-items:center;justify-content:center;padding:20px;z-index:50}
.modal-card{width:min(620px,100%);background:#fff;border-radius:18px;padding:22px 24px;max-height:88vh;overflow:auto;box-shadow:0 30px 80px rgba(0,0,0,.3)}
.modal-card.wide{width:min(980px,100%)}
.modal-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}
.modal-head h2{margin:0;font-size:20px}
.close{background:none;border:0;font-size:26px;line-height:1;color:#7b8da0}
.plans{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:16px 0}
.plan{border:1px solid var(--line);border-radius:12px;padding:14px;text-align:center}
.plan strong{display:block;font-size:18px;color:var(--navy)}
.plan .price{color:var(--blue);font-weight:800;margin:6px 0}
.plan .primary{width:100%;padding:8px}
.admin-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px}
.admin-grid h3{font-size:14px;color:var(--muted);margin:6px 0 10px}
.admin-table{border:1px solid var(--line);border-radius:10px;overflow:hidden;font-size:12.5px}
.admin-row{display:grid;grid-template-columns:1fr 70px 64px;gap:6px;padding:8px 10px;border-bottom:1px solid #edf3f9;align-items:center}
.admin-row:last-child{border-bottom:0}
.admin-row.head{background:#f6faff;color:var(--muted);font-weight:700}
.admin-row .ghost{padding:4px 8px;font-size:11.5px}
.order-row{display:grid;grid-template-columns:1fr 70px 70px;gap:6px;padding:8px 10px;border-bottom:1px solid #edf3f9;align-items:center}
.toast{position:fixed;left:50%;bottom:26px;transform:translateX(-50%);background:#102a43;color:#fff;padding:10px 16px;border-radius:10px;z-index:99;box-shadow:0 10px 30px rgba(0,0,0,.25);font-size:13px}
.toast.error{background:#9b2c2c}

@media(max-width:860px){
  .layout{grid-template-columns:1fr}
  .sidebar{position:static;height:auto;border-right:0;border-bottom:1px solid var(--line)}
  .history{flex-direction:row;overflow:auto;padding-bottom:4px}
  .history-item{min-width:180px}
  .main{padding:18px}
  .composer{padding:20px}
  .composer-head{flex-direction:column}
  .subject-chip{white-space:normal}
  .result-head{flex-direction:column}
  .exp-row{grid-template-columns:48px 82px 1fr;gap:8px}
  .plans{grid-template-columns:1fr}
  .admin-grid{grid-template-columns:1fr}
}

/* 公开题库 */
.public-body{background:linear-gradient(180deg,#eef5fb,#f7fafc 420px)}
.public-top{height:66px;background:#fff;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 clamp(16px,4vw,44px);position:sticky;top:0;z-index:10}
.nav-link{display:inline-flex;align-items:center;text-decoration:none;padding:9px 14px}
.public-main{max-width:1180px;margin:0 auto;padding:34px clamp(16px,4vw,44px) 70px}
.public-hero{padding:10px 0 26px}
.public-hero h1{font-size:34px;margin:0 0 8px;color:var(--navy);letter-spacing:.5px}
.public-hero p{max-width:720px;color:#4a6076;margin:0}
.public-stats{display:flex;gap:10px;margin-top:14px;color:var(--muted);font-size:13px}
.public-stats span{background:#fff;border:1px solid var(--line);border-radius:999px;padding:5px 11px}
.public-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}
.pub-card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:17px 18px;box-shadow:0 6px 20px rgba(16,42,67,.05);cursor:pointer;transition:transform .15s ease,border-color .15s ease}
.pub-card:hover{transform:translateY(-2px);border-color:#bcd6ea}
.pub-card-top{display:flex;justify-content:space-between;align-items:center;gap:8px;margin-bottom:10px}
.pub-subject{font-size:12px;color:#15598f;background:#eef7ff;border:1px solid #d5e8f8;border-radius:999px;padding:3px 9px}
.pub-date{font-size:11.5px;color:var(--muted)}
.pub-question{font-size:15px;line-height:1.7;margin:0 0 14px;display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;overflow:hidden;white-space:pre-wrap}
.pub-card-bottom{display:flex;justify-content:space-between;align-items:center}
.pub-answer{font-weight:900;color:var(--green);font-size:14px}
.pub-empty{padding:30px;text-align:center;color:var(--muted)}
.public-more{text-align:center;margin:22px 0}
.public-detail-card{width:min(900px,100%)}
.pub-detail-answer{font-size:18px;margin:8px 0 14px;color:var(--muted)}
.pub-detail-answer strong{font-size:28px;color:var(--green);margin-left:8px}
.pub-exps{padding:0;border-top:1px solid var(--line)}
.pub-image-card{margin-top:10px}
@media(max-width:760px){.public-grid{grid-template-columns:1fr}.public-hero h1{font-size:28px}}

.admin-q-row{display:grid;grid-template-columns:1fr 70px 88px;gap:8px;align-items:center;padding:8px 10px;border-bottom:1px solid #edf3f9;font-size:12.5px}
.admin-q-row:last-child{border-bottom:0}
.admin-q-text{display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;white-space:pre-wrap}

.public-detail-card h2{white-space:pre-wrap}

.summary-line{display:flex;gap:10px;align-items:flex-start;padding:14px 24px;background:#f3f9ff;border-bottom:1px solid var(--line);color:#24425f;font-size:14px;line-height:1.7}
.summary-label{flex:0 0 auto;color:var(--blue);font-weight:800;font-size:12px;border:1px solid #cfe4f7;background:#fff;border-radius:999px;padding:2px 8px;margin-top:2px}
.pub-summary{background:#f3f9ff;border:1px solid #dcecf9;border-radius:10px;padding:10px 13px;margin:0 0 14px;color:#24425f;font-size:13.5px;line-height:1.7}

.modal-card.small{width:min(460px,100%)}
.stack label,.field{display:block;margin:12px 0;font-size:13px;font-weight:600;color:#39506a}
.stack input,.field input{width:100%;margin-top:6px;padding:10px 12px;border:1px solid var(--line);border-radius:9px;background:#f8fbfe;outline:none}
.stack input:focus,.field input:focus{border-color:var(--blue);background:#fff}
.form-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:18px}
.danger{background:#fff;border:1px solid #f0c7c7;color:#a22;border-radius:10px;padding:9px 12px}
.danger:hover{background:#fff5f5}
.admin-row{grid-template-columns:1fr 70px 190px}
.admin-actions{display:flex;gap:6px;justify-content:flex-end}
.admin-actions .ghost{padding:5px 8px;font-size:11.5px}

@media(max-width:760px){
  .topbar{height:auto;min-height:66px;flex-wrap:wrap;padding:8px 12px;gap:8px}
  .topbar .brand span{display:none}
  .top-actions{flex-wrap:wrap;justify-content:flex-end;gap:6px}
  .top-actions .ghost,.top-actions .pill{padding:7px 9px;font-size:12.5px}
  .user-name{max-width:90px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
  .admin-row{grid-template-columns:minmax(0,1fr) 52px 142px;gap:4px;padding:7px 8px}
  .admin-actions{gap:4px}
  .admin-actions .ghost,.admin-actions .danger{padding:4px 6px;font-size:11px}
  .modal-card.wide{width:100%;padding:16px}
}

#confirm-modal{z-index:80}
.confirm-text{font-size:14px;line-height:1.8;color:#33465a;margin:10px 0 18px;white-space:pre-wrap}

#credit-modal,#password-modal{z-index:70}
#confirm-modal{z-index:80}

.composer{position:relative}
.composer.dragover{border-color:var(--blue);box-shadow:0 0 0 4px rgba(31,111,178,.16)}
.composer.dragover::after{content:"松开鼠标，直接上传这张截图";position:absolute;inset:10px;border:2px dashed var(--blue);border-radius:14px;background:rgba(238,247,255,.92);display:flex;align-items:center;justify-content:center;color:var(--blue);font-size:20px;font-weight:800;z-index:5;pointer-events:none}