:root{
  --blue:#1b3fa0; --blue2:#3b6fe0; --blueL:#eaf0ff; --blueLL:#f5f8ff;
  --ink:#16223d; --muted:#6b7a99; --line:#e3e9f5; --bg:#eef2f9;
  --ok:#0f9960; --okbg:#e7f7f0; --bad:#d93636; --badbg:#fdecec; --warnbg:#fff8e6; --warn:#b06a00;
}
*{box-sizing:border-box}
body{
  margin:0; background:var(--bg); color:var(--ink);
  font-family:"PingFang SC","Microsoft YaHei","Segoe UI",system-ui,sans-serif;
  font-size:15px; line-height:1.7;
}
.wrap{max-width:980px;margin:0 auto;padding:22px 18px 60px}

/* Hero */
.hero{
  background:linear-gradient(120deg,var(--blue) 0%,#2450c8 55%,#2f63e0 100%);
  color:#fff;border-radius:14px;padding:26px 28px 22px;box-shadow:0 8px 24px rgba(27,63,160,.18);
}
.hero h1{margin:0 0 8px;font-size:24px;letter-spacing:.5px}
.hero .sub{margin:0 0 18px;font-size:13px;opacity:.9}
.modes{display:flex;gap:12px;flex-wrap:wrap}
.mode{
  border:1px solid rgba(255,255,255,.35);background:rgba(255,255,255,.14);color:#fff;
  padding:9px 20px;border-radius:999px;font-size:14px;cursor:pointer;font-family:inherit;
  transition:.18s;
}
.mode:hover{background:rgba(255,255,255,.26)}
.mode.active{background:#fff;color:var(--blue);font-weight:600;border-color:#fff}
.mode span{margin-right:4px}

/* Tabs */
.tabbar{display:flex;align-items:center;justify-content:space-between;margin:18px 0 0;gap:12px;flex-wrap:wrap}
.tabs{display:flex;gap:8px}
.tab{
  border:1px solid var(--line);background:#fff;color:var(--muted);
  padding:9px 20px;border-radius:8px;cursor:pointer;font-size:14px;font-family:inherit;
}
.tab.active{background:var(--blue);border-color:var(--blue);color:#fff;font-weight:600}
.ghost{
  border:1px solid var(--line);background:#fff;color:var(--ink);
  padding:8px 16px;border-radius:8px;cursor:pointer;font-size:13px;font-family:inherit;
}
.ghost:hover{border-color:var(--blue2);color:var(--blue)}
.primary{
  border:none;background:var(--blue);color:#fff;padding:9px 22px;border-radius:8px;
  cursor:pointer;font-size:14px;font-family:inherit;
}
.primary:hover{background:var(--blue2)}

/* Notice */
.notice{
  background:var(--warnbg);border:1px solid #f3e0ac;color:var(--warn);
  border-radius:8px;padding:11px 16px;margin:14px 0 18px;font-size:13px;
}

/* Cards */
.q{background:#fff;border:1px solid var(--line);border-radius:10px;padding:20px 22px;margin-bottom:16px;box-shadow:0 1px 3px rgba(22,34,61,.04)}
.q-head{display:flex;gap:10px;align-items:flex-start}
.q-no{color:var(--blue);font-weight:700;flex:none}
.stem{margin:0;font-weight:600}
.opts{margin:14px 0 0;display:flex;flex-direction:column;gap:8px}
.opt{
  border:1px solid var(--line);background:#fff;border-radius:8px;padding:10px 14px;
  cursor:pointer;display:flex;gap:10px;align-items:flex-start;font-family:inherit;font-size:14px;
  color:var(--ink);text-align:left;transition:.15s;
}
.opt:hover{border-color:var(--blue2);background:var(--blueLL)}
.opt .k{color:var(--blue2);font-weight:700;flex:none;width:14px}
.opt.sel{border-color:var(--blue);background:var(--blueL)}
.opt.right{border-color:var(--ok);background:var(--okbg)}
.opt.right .k{color:var(--ok)}
.opt.wrong{border-color:var(--bad);background:var(--badbg)}
.opt.wrong .k{color:var(--bad)}
.opt[disabled]{cursor:default}
.extra,.qextra{margin:12px 0 0;padding:10px 14px;background:var(--blueLL);border-left:3px solid var(--blue2);
  border-radius:0 6px 6px 0;font-size:13px;color:#41547d;white-space:pre-wrap}

.ansbar{display:flex;gap:10px;align-items:center;margin-top:14px;flex-wrap:wrap}
.showbtn{
  border:1px solid var(--line);background:#f7f9fd;color:var(--blue);
  padding:5px 14px;border-radius:6px;cursor:pointer;font-size:13px;font-family:inherit;
}
.showbtn:hover{border-color:var(--blue2)}
.explain{
  margin-top:12px;padding:14px 16px;background:#fbfcff;border:1px solid var(--line);
  border-radius:8px;font-size:13.5px;color:#3c4a66;white-space:pre-wrap;
}
.explain .tag{color:var(--ok);font-weight:700}
.explain .tag.bad{color:var(--bad)}

/* case / essay */
.block{background:#fff;border:1px solid var(--line);border-radius:10px;padding:22px;margin-bottom:18px;box-shadow:0 1px 3px rgba(22,34,61,.04)}
.block h2{margin:0 0 6px;font-size:19px;color:var(--blue)}
.block h3{margin:18px 0 6px;font-size:15.5px;color:var(--blue2)}
.block p{margin:8px 0}
.scenario{white-space:pre-wrap;background:var(--blueLL);border-left:3px solid var(--blue2);border-radius:0 6px 6px 0;padding:12px 15px;font-size:14px}
.q-item{margin-top:18px;padding-top:14px;border-top:1px dashed var(--line)}
.q-item .stem{font-weight:600}
.q-item ol{margin:8px 0 0;padding-left:22px}
.q-item li{margin:5px 0}
.badge{display:inline-block;background:var(--blueL);color:var(--blue);border-radius:5px;padding:2px 9px;font-size:12.5px;margin-right:8px}
.essay-body h4{margin:14px 0 4px;font-size:14.5px;color:#2b3c5e}
.essay-body p{margin:0 0 8px;text-align:justify}

/* score */
.score{background:linear-gradient(120deg,var(--blue),#2f63e0);color:#fff;border-radius:12px;padding:26px;text-align:center;margin-bottom:18px}
.score .big{font-size:46px;font-weight:700;line-height:1.1}
.score .lab{font-size:14px;opacity:.92}
.score .verdict{margin-top:8px;font-size:15px;font-weight:600}
table.rec{width:100%;border-collapse:collapse;background:#fff;font-size:13.5px;border-radius:10px;overflow:hidden;border:1px solid var(--line)}
table.rec th,table.rec td{padding:10px 14px;text-align:left;border-bottom:1px solid var(--line)}
table.rec th{background:var(--blueL);color:var(--blue);font-weight:600}
table.rec tr:last-child td{border-bottom:none}
.empty{text-align:center;color:var(--muted);padding:40px;background:#fff;border:1px solid var(--line);border-radius:10px}

/* timer */
.timer{position:sticky;top:0;z-index:5;background:#fff;border:1px solid var(--line);border-radius:10px;
  padding:10px 18px;margin-bottom:16px;display:flex;gap:16px;align-items:center;box-shadow:0 2px 8px rgba(22,34,61,.06)}
.timer .t{font-size:20px;font-weight:700;color:var(--blue);font-variant-numeric:tabular-nums}
.timer .p{margin-left:auto;font-size:13px;color:var(--muted)}
.progress{height:6px;background:var(--line);border-radius:3px;overflow:hidden;flex:1;max-width:220px}
.progress i{display:block;height:100%;background:var(--blue2);width:0;transition:.3s}

/* footer */
.foot{margin-top:26px;display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;
  font-size:12.5px;color:var(--muted);border-top:1px solid var(--line);padding-top:14px}

/* modal & toast */
.modal{position:fixed;inset:0;background:rgba(15,25,50,.45);display:none;align-items:center;justify-content:center;z-index:50}
.modal.show{display:flex}
.modal-box{background:#fff;border-radius:12px;padding:26px 28px;max-width:420px;width:92%}
.modal-box h3{margin:0 0 8px;font-size:17px}
.modal-box p{margin:0 0 18px;font-size:14px;color:var(--muted)}
.modal-btns{display:flex;gap:10px;justify-content:flex-end}
.toast{position:fixed;left:50%;bottom:34px;transform:translateX(-50%) translateY(20px);
  background:rgba(22,34,61,.92);color:#fff;padding:10px 20px;border-radius:8px;font-size:13.5px;
  opacity:0;pointer-events:none;transition:.25s;z-index:60}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

@media(max-width:640px){
  .hero h1{font-size:19px}
  .q{padding:16px}
  .tabbar{justify-content:flex-start}
}