:root { color-scheme: light; --primary:#2457d6; --primary-dark:#173fa9; --ink:#172033; --muted:#667085; --line:#d7deea; --surface:#fff; --danger:#c43232; --success:#147a4b; }
* { box-sizing:border-box; }
body { margin:0; background:linear-gradient(180deg,#eaf0fb 0%,#f7f9fd 45%,#eef3fb 100%); color:var(--ink); font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Microsoft YaHei",sans-serif; min-height:100vh; }
button,input,select,textarea { font:inherit; }
button { cursor:pointer; border:1px solid var(--line); border-radius:12px; background:#fff; padding:11px 14px; color:var(--ink); transition:transform .08s ease, background .12s ease; }
button:active { transform:scale(.98); }
button.primary { background:var(--primary); border-color:var(--primary); color:#fff; font-weight:700; }
button.primary:active { background:var(--primary-dark); }
button.ghost { background:transparent; } button.small { padding:7px 10px; border-radius:9px; } button.wide { width:100%; }
button:disabled { opacity:.55; cursor:wait; } .hidden { display:none !important; }
button[aria-busy="true"] { position:relative; }
button[aria-busy="true"]::after { content:""; display:inline-block; width:12px; height:12px; margin-left:8px; border:2px solid currentColor; border-right-color:transparent; border-radius:50%; vertical-align:-2px; animation:button-spin .7s linear infinite; }
@keyframes button-spin { to { transform:rotate(360deg); } }
.shell { width:min(900px,100%); margin:0 auto; padding:18px 14px 40px; }
.auth-card,.card { background:var(--surface); border:1px solid rgba(23,32,51,.08); border-radius:20px; padding:20px; margin-bottom:16px; box-shadow:0 12px 30px rgba(31,53,93,.08); }
.auth-card { margin-top:8vh; } .brand-block { display:flex; gap:14px; align-items:center; margin-bottom:20px; }
.brand-mark { width:54px; height:54px; border-radius:16px; background:var(--primary); color:#fff; display:grid; place-items:center; font-size:26px; font-weight:800; }
h1,h2,p { margin-top:0; } h1 { font-size:24px; margin-bottom:6px; } h2 { font-size:19px; }
.form-stack,.filter-grid { display:grid; gap:12px; } label { display:grid; gap:6px; color:#344054; font-size:14px; }
input,select,textarea { width:100%; border:1px solid var(--line); border-radius:12px; padding:12px; background:#fff; color:var(--ink); }
textarea { min-height:110px; resize:vertical; } .button-row,.header-actions { display:flex; gap:8px; } .button-row>* { flex:1; }
.message { color:var(--danger); min-height:22px; } .hint,.subtle { color:var(--muted); font-size:13px; }
.app-header { position:sticky; top:0; z-index:5; display:flex; justify-content:space-between; align-items:center; padding:10px 0 12px; backdrop-filter:blur(14px); }
.tabs { display:grid; grid-template-columns:repeat(3,1fr); gap:6px; background:rgba(255,255,255,.76); padding:6px; border:1px solid var(--line); border-radius:16px; margin-bottom:14px; position:sticky; top:56px; z-index:4; }
.tab { border:0; background:transparent; padding:9px 4px; } .tab.active { background:var(--primary); color:#fff; font-weight:700; }
.filter-grid { grid-template-columns:repeat(2,minmax(0,1fr)); margin-bottom:14px; }
.filter-grid.compact { margin-bottom:12px; }
.practice-head { display:flex; justify-content:space-between; align-items:center; color:var(--muted); }
.question-text { font-size:18px; line-height:1.72; white-space:pre-wrap; }
.option-row { display:flex; gap:10px; align-items:flex-start; padding:12px; border:1px solid var(--line); border-radius:12px; margin:8px 0; background:#fbfcff; }
.option-row input { width:auto; margin-top:4px; } .option-row label { display:block; flex:1; color:var(--ink); }
.option-row img { max-width:min(100%,680px); border-radius:10px; display:block; margin-top:8px; }
.answer-area { margin-top:16px; } .result { margin-top:14px; padding:14px; border-radius:12px; background:#f5f8ff; border:1px solid var(--line); line-height:1.65; white-space:pre-wrap; }
.result.correct { background:#effaf4; border-color:#b7e2ca; color:var(--success); } .result.wrong { background:#fff2f2; border-color:#f4c5c5; color:var(--danger); }
.list { display:grid; gap:10px; } .list-item { border:1px solid var(--line); border-radius:12px; padding:12px; background:#fcfdff; min-width:0; overflow-wrap:anywhere; } .list-item strong { display:block; margin-bottom:5px; line-height:1.45; word-break:break-word; }
.summary-grid { display:grid; grid-template-columns:repeat(2,1fr); gap:10px; } .summary-item { background:#f5f8ff; border-radius:12px; padding:14px; } .summary-item b { display:block; font-size:26px; color:var(--primary); }
.banner { position:fixed; z-index:20; top:0; left:0; right:0; text-align:center; padding:8px; background:#fff1c9; color:#7a5300; }
.spaced { margin-top:12px; }
.list-item.action { cursor:pointer; }
.list-item.action:active { background:#edf3ff; }
.option-row.correct { border-color:#8bd0a9; background:#effaf4; }
.option-row.incorrect { border-color:#efb0b0; background:#fff2f2; }
.wrong-detail-title { margin-bottom:12px; overflow-wrap:anywhere; }
.wrong-detail-grid { display:grid; gap:6px; margin:12px 0; color:#344054; }
.wrong-detail-answer { padding:10px 12px; background:#f5f8ff; border-radius:10px; white-space:pre-wrap; overflow-wrap:anywhere; }
.assessment-history { display:grid; gap:8px; margin-top:10px; }
.practice-view { position:fixed; inset:0; z-index:10; display:flex; flex-direction:column; background:linear-gradient(180deg,#eaf0fb 0%,#f7f9fd 45%,#eef3fb 100%); padding-top:env(safe-area-inset-top); }
.practice-top { display:grid; grid-template-columns:auto 1fr auto; gap:10px; align-items:center; padding:10px 12px; background:rgba(255,255,255,.92); border-bottom:1px solid var(--line); backdrop-filter:blur(14px); }
.practice-meta { display:grid; gap:1px; text-align:center; }
.practice-meta .subtle { min-height:18px; }
.practice-scroll { flex:1; min-height:0; overflow-y:auto; overscroll-behavior:contain; -webkit-overflow-scrolling:touch; padding:12px; }
.practice-card { margin:0; min-height:calc(100% - 4px); }
.practice-actions { display:grid; gap:8px; padding:10px 12px calc(10px + env(safe-area-inset-bottom)); background:rgba(255,255,255,.96); border-top:1px solid var(--line); backdrop-filter:blur(14px); }
.practice-actions button { min-height:48px; }
.modal { position:fixed; inset:0; z-index:30; overflow-y:auto; padding:12px; background:rgba(16,24,40,.48); }
.modal-card { width:min(680px,100%); margin:max(18px,env(safe-area-inset-top)) auto 18px; background:#fff; border:1px solid rgba(23,32,51,.08); border-radius:20px; padding:18px; box-shadow:0 20px 50px rgba(16,24,40,.26); }
.modal-head { display:flex; justify-content:space-between; gap:12px; align-items:flex-start; margin-bottom:14px; }
.modal-head h2 { margin-bottom:4px; }
.settings-grid { display:grid; grid-template-columns:repeat(2,minmax(0,1fr)); gap:12px; margin-bottom:14px; }
.switch-list { display:grid; gap:8px; margin:0 0 16px; }
.switch-row { display:flex; align-items:center; gap:10px; padding:10px 12px; border:1px solid var(--line); border-radius:12px; color:var(--ink); }
.switch-row input { width:20px; height:20px; flex:0 0 auto; }
.practice-mode { overflow:hidden; }
.practice-mode .app-header, .practice-mode .tabs { display:none !important; }
@media (min-width:700px) { .filter-grid { grid-template-columns:repeat(5,minmax(0,1fr)); } }
@media (min-width:700px) { .settings-grid { grid-template-columns:repeat(3,minmax(0,1fr)); } }
@media (max-width:480px) {
  .shell { padding:12px 10px calc(28px + env(safe-area-inset-bottom)); }
  .auth-card,.card { padding:15px; border-radius:16px; margin-bottom:12px; }
  .app-header { align-items:flex-start; gap:8px; }
  .app-header .header-actions { flex-wrap:wrap; justify-content:flex-end; gap:6px; }
  .app-header .header-actions button { padding:7px 9px; }
  .tabs { gap:4px; padding:4px; top:52px; margin-bottom:10px; }
  .tab { font-size:13px; padding:9px 2px; }
  .filter-grid { gap:8px; }
  .filter-grid.compact { grid-template-columns:repeat(2,minmax(0,1fr)); }
  .list { gap:8px; }
  .list-item { padding:10px; border-radius:10px; }
  .question-text { font-size:17px; line-height:1.62; }
  .wrong-detail-grid { gap:5px; }
  .wrong-detail-answer { padding:9px 10px; font-size:14px; }
}