:root {
  font-family:ui-rounded,"Microsoft YaHei","PingFang SC",system-ui,sans-serif;
  color:#253b37;
  background:#f6f5ed;
  font-synthesis:none;
  --green:#176b53;
  --ink:#253b37;
  --muted:#62716a;
  --line:#dfe4d8;
  --yellow:#f5c960;
  --paper:#fffef9
}

* {
  box-sizing:border-box
}
body {
  margin:0
}
button,input {
  font:inherit
}
button,a,input {
  -webkit-tap-highlight-color:transparent
}
button {
  cursor:pointer
}
a {
  color:inherit;
  text-decoration:none
}
button:focus-visible,a:focus-visible,input:focus-visible,summary:focus-visible {
  outline:3px solid #d39928;
  outline-offset:4px
}
button:disabled {
  cursor:wait;
  opacity:.6
}
.topbar {
  max-width:1080px;
  margin:auto;
  padding:28px 32px;
  display:flex;
  align-items:center;
  justify-content:space-between
}
.brand {
  display:flex;
  gap:12px;
  align-items:center;
  font-size:20px;
  font-weight:800
}
.brand-icon {
  display:grid;
  place-items:center;
  width:42px;
  height:42px;
  background:var(--green);
  border-radius:14px;
  color:#fff;
  font-size:30px;
  line-height:1
}
.brand small {
  display:block;
  font-size:11px;
  font-weight:500;
  color:var(--muted);
  margin-top:3px;
  letter-spacing:1px
}
.version {
  font-size:11px;
  color:#65766b;
  letter-spacing:1.4px;
  border:1px solid #d9e0d3;
  padding:7px 10px;
  border-radius:30px
}
main {
  max-width:1016px;
  margin:12px auto 0;
  padding:0 0 30px;
  min-height:70vh
}
h1,h2,h3,p {
  margin-top:0
}
h1 {
  font-size:42px;
  line-height:1.3;
  letter-spacing:-1px;
  margin-bottom:16px
}
h2 {
  font-size:24px;
  line-height:1.4;
  margin-bottom:14px
}
h3 {
  font-size:17px;
  margin-bottom:10px
}
p {
  line-height:1.8
}
.muted,.hint {
  color:var(--muted)
}
.hint {
  font-size:13px;
  line-height:1.7
}
.eyebrow {
  font-size:12px;
  letter-spacing:2px;
  font-weight:700;
  color:var(--green);
  margin-bottom:18px
}
.hero {
  display:grid;
  grid-template-columns:1.2fr 1fr;
  border-radius:30px;
  background:#e8eddf;
  overflow:hidden;
  min-height:310px;
  border:1px solid #e0e6d6
}
.hero-copy {
  padding:40px 40px 36px
}
.hero-copy p {
  max-width:340px;
  font-size:15px;
  margin-bottom:0
}
.tag {
  display:inline-flex;
  align-items:center;
  gap:7px;
  font-size:12px;
  background:#fff8de;
  border:1px solid #e6d79f;
  color:#69551c;
  padding:6px 10px;
  border-radius:8px
}
.hero-tags {
  display:flex;
  gap:8px;
  margin-top:24px
}
.hero-tags span {
  font-size:12px;
  color:#41684f;
  padding:6px 10px;
  border:1px solid #ccd7c0;
  border-radius:7px
}
.math-art {
  position:relative;
  display:flex;
  align-items:center;
  justify-content:center;
  min-height:280px;
  overflow:hidden;
  background:radial-gradient(ellipse at 55% 120%,#edc875 0 43%,transparent 43.3%),radial-gradient(ellipse at 120% 125%,#ddb269 0 55%,transparent 55.4%)
}
.math-art:before {
  content:'';
  position:absolute;
  width:68px;
  height:68px;
  top:27px;
  right:28px;
  border-radius:50%;
  background:#f9d67b
}
.math-card {
  position:relative;
  border:1px solid #d6dbca;
  border-radius:18px;
  background:var(--paper);
  padding:25px 28px;
  transform:rotate(-4deg);
  box-shadow:0 12px 0 #52735812;
  min-width:270px
}
.art-label {
  font-size:12px;
  color:#74806f;
  margin-bottom:18px
}
.art-equation {
  font-size:38px;
  font-weight:800;
  letter-spacing:2px;
  font-variant-numeric:tabular-nums;
  color:var(--green);
  margin:0 0 8px
}
.art-notes {
  display:flex;
  justify-content:space-between;
  gap:20px;
  font-size:12px;
  color:#67745e
}
.art-answer {
  border-top:1px dashed #d6ddca;
  margin-top:18px;
  padding-top:14px;
  text-align:right;
  font-size:28px;
  font-weight:750;
  color:#896a29
}
.section-title {
  display:flex;
  align-items:center;
  justify-content:space-between;
  margin:32px 0 16px
}
.section-title h2 {
  font-size:20px;
  margin:0
}
.section-title span {
  font-size:12px;
  color:var(--muted)
}
.action-grid {
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:16px
}
.action-card {
  background:var(--paper);
  border:1px solid var(--line);
  padding:24px;
  border-radius:20px;
  display:flex;
  gap:18px;
  align-items:flex-start
}
.step {
  width:42px;
  height:42px;
  flex-shrink:0;
  border-radius:13px;
  display:grid;
  place-items:center;
  background:#edf1e4;
  color:var(--green);
  font-weight:800;
  font-size:18px
}
.step.yellow {
  background:#fbefca;
  color:#8b681e
}
.action-body {
  flex:1
}
.action-body p {
  font-size:13px;
  color:var(--muted);
  margin-bottom:18px
}
.button {
  border:0;
  min-height:46px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:12px;
  padding:12px 20px;
  border-radius:12px;
  background:var(--green);
  color:white;
  font-weight:700;
  font-size:14px;
  line-height:1.5
}
.button:hover {
  filter:brightness(.95)
}
.button.secondary {
  background:#edf1e5;
  color:#28573f;
  border:1px solid #d4decc
}
.button.yellow {
  background:var(--yellow);
  color:#4f421f
}
.button.ghost {
  background:transparent;
  color:var(--green);
  border:1px solid #cfd9c7
}
.button.full {
  width:100%
}
.link-button {
  background:none;
  border:0;
  color:var(--green);
  font-size:14px;
  padding:10px 0;
  font-weight:700
}
.history-link {
  display:flex;
  align-items:center;
  justify-content:space-between;
  border:1px solid var(--line);
  border-radius:16px;
  padding:18px 24px;
  margin-top:16px;
  background:#fffef980
}
.history-link strong {
  font-size:15px
}
.history-link span {
  font-size:12px;
  color:var(--muted)
}
.privacy {
  margin:22px 0 0;
  text-align:center;
  color:#7a8174;
  font-size:12px
}
.footer {
  max-width:1016px;
  border-top:1px solid var(--line);
  margin:0 auto;
  padding:22px 0 30px;
  font-size:12px;
  color:#788475;
  display:flex;
  justify-content:space-between
}
.narrow {
  max-width:720px;
  margin:0 auto
}
.page-head {
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:12px;
  margin:12px 0 24px
}
.back {
  font-size:13px;
  color:var(--green);
  border:0;
  padding:10px 0;
  background:none
}
.badge {
  font-size:12px;
  color:#52735d;
  background:#e8eedf;
  padding:6px 10px;
  border-radius:8px
}
.page-title {
  font-size:30px;
  letter-spacing:0
}
.page-subtitle {
  font-size:14px;
  color:var(--muted);
  margin-bottom:24px
}
.panel {
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:22px;
  padding:28px;
  margin-bottom:18px
}
.notice {
  border:1px solid #dedfbc;
  background:#f8f4dd;
  color:#67603d;
  padding:14px 16px;
  border-radius:12px;
  font-size:13px;
  line-height:1.7;
  margin-bottom:18px
}
.error {
  border:1px solid #ecc4b3;
  background:#fff1e9;
  color:#9a432b;
  padding:14px 16px;
  border-radius:12px;
  line-height:1.7;
  font-size:14px;
  margin:14px 0
}
.practice-meta {
  display:flex;
  justify-content:space-between;
  gap:12px;
  align-items:center;
  font-size:13px;
  margin:18px 0;
  color:var(--muted)
}
.timer {
  font-variant-numeric:tabular-nums;
  font-weight:700;
  color:var(--ink)
}
.progress {
  height:5px;
  background:#e4e9dd;
  border-radius:10px;
  margin-bottom:24px;
  overflow:hidden
}
.progress-fill {
  height:100%;
  background:var(--green);
  transition:width .15s
}
progress {
  appearance:none;
  border:0;
  width:100%;
  height:6px;
  margin:0 0 22px
}
progress::-webkit-progress-bar {
  background:#e4e9dd;
  border-radius:10px
}
progress::-webkit-progress-value {
  background:var(--green);
  border-radius:10px
}
.question-list {
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:12px
}
.question-row {
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px;
  padding:18px;
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:15px
}
.question-no {
  color:#87917e;
  font-size:11px;
  width:18px;
  flex-shrink:0
}
.equation {
  font-size:20px;
  white-space:nowrap;
  font-weight:650;
  font-variant-numeric:tabular-nums
}
.answer-input {
  width:96px;
  min-width:0;
  height:48px;
  border:1px solid #bac9b0;
  border-radius:10px;
  background:#f7f9f1;
  padding:8px;
  text-align:center;
  font-size:21px;
  font-weight:650;
  color:var(--green);
  font-variant-numeric:tabular-nums
}
.answer-input[aria-invalid=true] {
  border:2px solid #ac4d31;
  background:#fff1e9
}
.form-bottom {
  display:flex;
  justify-content:space-between;
  gap:16px;
  align-items:center;
  margin-top:24px
}
.form-bottom p {
  font-size:12px;
  line-height:1.7;
  color:var(--muted);
  margin:0
}
.sticky-actions {
  margin-top:24px
}
.self-question {
  font-size:27px;
  line-height:1.6;
  margin:8px 0 24px
}
.option-list {
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:12px
}
.option {
  border:1px solid #d3decb;
  border-radius:12px;
  background:#f6f8f0;
  min-height:64px;
  padding:14px;
  color:var(--ink);
  font-size:21px;
  font-weight:650
}
.option:hover {
  background:#e4edd9
}
.skip {
  display:block;
  margin:20px auto 0;
  color:#6f705e;
  border:0;
  background:none;
  text-decoration:underline;
  text-underline-offset:5px;
  font-size:14px;
  padding:12px
}
.reason-option {
  width:100%;
  display:block;
  text-align:left;
  padding:15px;
  margin-bottom:10px;
  border:1px solid #d4decb;
  background:#f7f8ef;
  border-radius:10px;
  color:var(--ink);
  font-size:15px
}
.stats {
  display:grid;
  grid-template-columns:repeat(4,1fr);
  gap:10px;
  margin-bottom:26px
}
.stat {
  background:#eef2e5;
  border-radius:14px;
  padding:18px 12px;
  text-align:center
}
.stat strong {
  display:block;
  font-size:28px;
  color:var(--green);
  font-variant-numeric:tabular-nums;
  line-height:1.4
}
.stat span {
  font-size:12px;
  color:#63725d;
  display:block;
  margin-top:3px
}
.report-hero {
  border:1px solid #d8e2cc;
  background:#eaf0e0;
  padding:28px;
  border-radius:22px;
  margin-bottom:20px
}
.report-hero h1 {
  font-size:30px;
  letter-spacing:0
}
.report-hero p {
  font-size:14px;
  margin-bottom:0;
  color:#536b50
}
.report-section {
  padding:22px 0;
  border-top:1px solid var(--line)
}
.report-section h2 {
  font-size:18px
}
.report-section p {
  font-size:14px;
  margin-bottom:0
}
.result-row {
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:8px;
  border-top:1px solid #e6e9df;
  padding:14px 0;
  font-size:14px
}
.result-row .expression {
  font-size:18px;
  font-weight:650
}
.answer-detail {
  color:#795142
}
.correct {
  color:var(--green);
  font-weight:700
}
.result-row.blank .answer-detail {
  color:#7b7261
}
.report-actions {
  display:flex;
  gap:12px;
  flex-wrap:wrap;
  margin-top:20px
}
.record {
  border:1px solid var(--line);
  background:var(--paper);
  border-radius:15px;
  margin:12px 0;
  padding:20px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px
}
.record-title {
  font-size:15px;
  font-weight:700;
  margin-bottom:8px
}
.record-meta {
  font-size:12px;
  color:var(--muted);
  line-height:1.7
}
.record-score {
  font-size:23px;
  font-weight:800;
  color:var(--green);
  text-align:right
}
.record-score small {
  display:block;
  font-size:10px;
  font-weight:400;
  color:var(--muted)
}
.empty {
  text-align:center;
  padding:36px 20px;
  color:var(--muted);
  line-height:1.8
}
.empty-symbol {
  font-size:36px;
  color:#9aa888;
  margin-bottom:16px
}
.pill-list {
  display:flex;
  gap:8px;
  flex-wrap:wrap;
  margin:14px 0
}
.pill {
  display:inline-block;
  font-size:12px;
  padding:6px 10px;
  border-radius:7px;
  background:#f6ecd0;
  color:#806128
}
.learning-tip {
  margin-top:18px;
  font-size:13px;
  line-height:1.9;
  color:#63725d
}
.learning-tip summary {
  cursor:pointer;
  color:var(--green);
  font-weight:700
}
.learning-tip p {
  margin:12px 0 0
}
.lesson-example {
  font-size:16px;
  font-weight:600
}
.shuffle-control {
  display:flex;
  align-items:center;
  gap:7px;
  font-size:13px;
  color:var(--muted);
  margin-bottom:16px
}
.shuffle-control input {
  width:17px;
  height:17px;
  accent-color:var(--green)
}
.save-label {
  font-size:11px;
  color:#6f7c65
}
.sr-only {
  position:absolute;
  width:1px;
  height:1px;
  padding:0;
  margin:-1px;
  overflow:hidden;
  clip:rect(0,0,0,0);
  white-space:nowrap;
  border:0
}
.loading {
  text-align:center;
  padding:80px 20px
}
.help-heading {
  font-size:20px
}
.inline-link {
  text-decoration:underline;
  text-underline-offset:4px;
  color:var(--green)
}

@media(max-width:1080px) {
  main,.footer {
  margin-left:28px;
  margin-right:28px
}
.question-list {
  gap:10px
}
.question-row {
  padding:16px 12px;
  gap:8px
}
.equation {
  font-size:19px
}

}

@media(max-width:720px) {
  .topbar {
  padding:20px
}
.brand {
  font-size:18px
}
.brand small {
  font-size:10px
}
.version {
  font-size:9px;
  padding:6px 8px
}
main {
  margin:4px 20px 0;
  padding-bottom:28px
}
.hero {
  grid-template-columns:1fr;
  min-height:0;
  border-radius:23px
}
.hero-copy {
  padding:28px 26px 20px
}
h1 {
  font-size:34px
}
.hero-copy p {
  font-size:14px;
  max-width:none
}
.hero-tags {
  margin-top:16px
}
.math-art {
  min-height:200px;
  background:radial-gradient(ellipse at 55% 145%,#edc875 0 50%,transparent 50.5%),radial-gradient(ellipse at 120% 140%,#ddb269 0 60%,transparent 60.5%)
}
.math-art:before {
  width:48px;
  height:48px;
  top:14px;
  right:26px
}
.math-card {
  min-width:240px;
  padding:16px 22px;
  transform:rotate(-3deg);
  margin:4px 0 22px
}
.art-label {
  margin-bottom:10px
}
.art-equation {
  font-size:30px
}
.art-answer {
  font-size:23px;
  margin-top:12px;
  padding-top:8px
}
.action-grid {
  grid-template-columns:1fr;
  gap:12px
}
.action-card {
  padding:21px;
  gap:14px
}
.action-body h3 {
  font-size:18px
}
.action-body .button {
  width:100%
}
.section-title {
  margin-top:25px
}
.section-title h2 {
  font-size:18px
}
.section-title span {
  font-size:11px
}
.history-link {
  padding:17px
}
.history-link span {
  font-size:11px
}
.privacy {
  font-size:11px
}
.footer {
  margin:0 20px;
  padding:20px 0;
  font-size:10px
}
.page-title {
  font-size:27px
}
.panel {
  padding:22px 18px
}
.question-list {
  grid-template-columns:1fr;
  gap:10px
}
.question-row {
  padding:13px 18px;
  gap:14px
}
.equation {
  font-size:23px;
  flex:1
}
.answer-input {
  width:110px;
  height:48px
}
.question-no {
  width:20px
}
.form-bottom {
  flex-direction:column;
  align-items:stretch
}
.form-bottom .button {
  width:100%
}
.practice-meta {
  font-size:12px;
  flex-wrap:wrap
}
.stats {
  grid-template-columns:1fr 1fr;
  gap:10px
}
.stat {
  padding:17px 10px
}
.stat strong {
  font-size:26px
}
.report-hero {
  padding:24px 22px
}
.report-actions {
  display:grid;
  grid-template-columns:1fr 1fr
}
.report-actions .button:last-child {
  grid-column:1/-1
}
.self-question {
  font-size:25px
}
.option {
  font-size:20px
}
.record {
  padding:16px
}
.record-title {
  font-size:14px
}
.page-head {
  margin-top:0
}
.narrow {
  width:100%
}
.history-link {
  gap:10px
}

}

@media(prefers-reduced-motion:reduce) {
  * {
  transition:none!important;
  scroll-behavior:auto!important
}

}


#app:focus {
  outline: none;
}