:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --surface-2: #f0f2f5;
  --border: rgba(0, 0, 0, 0.09);
  --border-strong: rgba(0, 0, 0, 0.16);
  --text: #16181d;
  --text-2: #5c6270;
  --text-3: #8b909c;
  --accent: #2f6feb;
  --accent-soft: rgba(47, 111, 235, 0.1);
  --ok: #17864a;
  --ok-soft: rgba(23, 134, 74, 0.1);
  --bad: #d23b3b;
  --bad-soft: rgba(210, 59, 59, 0.1);
  --warn: #b4700d;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 4px 14px rgba(0, 0, 0, 0.04);
  --font: "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, sans-serif;
  --mono: "Cascadia Mono", Consolas, "Courier New", monospace;
}

html.dark {
  --bg: #0e1015;
  --surface: #171a21;
  --surface-2: #1e222b;
  --border: rgba(255, 255, 255, 0.09);
  --border-strong: rgba(255, 255, 255, 0.17);
  --text: #e8eaef;
  --text-2: #a2a8b6;
  --text-3: #757b8a;
  --accent: #6b9cff;
  --accent-soft: rgba(107, 156, 255, 0.14);
  --ok: #4fbb7f;
  --ok-soft: rgba(79, 187, 127, 0.14);
  --bad: #f0685f;
  --bad-soft: rgba(240, 104, 95, 0.14);
  --warn: #e0a441;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 4px 14px rgba(0, 0, 0, 0.25);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
}
.topbar-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
  height: 54px;
  display: flex;
  align-items: center;
  gap: 24px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 16px;
  font-weight: 500;
  color: var(--accent);
  flex-shrink: 0;
}
.topnav { display: flex; gap: 4px; margin-left: auto; }
.topnav a {
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  color: var(--text-2);
  transition: background .15s, color .15s;
}
.topnav a:hover { background: var(--surface-2); color: var(--text); }
.topnav a.active { color: var(--accent); background: var(--accent-soft); }
.topbar-right { display: flex; align-items: center; gap: 10px; }
.icon-btn {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--text-2);
}
.icon-btn:hover { background: var(--surface-2); color: var(--text); }
.sync-dot {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--text-3);
  transition: background .2s;
}
.sync-dot.synced { background: var(--ok); }
.sync-dot.syncing { background: var(--warn); animation: pulse 1s infinite; }
.sync-dot.error { background: var(--bad); }
@keyframes pulse { 50% { opacity: .3; } }

/* ---------- 搜索 ---------- */
.searchbar { position: sticky; top: 54px; z-index: 45; background: var(--bg); padding: 14px 0 0; }
.searchbar-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
  position: relative;
}
#searchInput {
  width: 100%;
  height: 40px;
  padding: 0 14px 0 38px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--text);
  font-size: 14px;
  font-family: inherit;
  outline: none;
  transition: border-color .15s, box-shadow .15s;
}
#searchInput:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.search-icon { position: absolute; left: 33px; top: 12px; color: var(--text-3); }
.search-results {
  position: absolute;
  top: 46px; left: 20px; right: 20px;
  max-height: 60vh;
  overflow-y: auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  z-index: 60;
  padding: 6px;
}
.sr-item {
  display: block;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  cursor: pointer;
}
.sr-item:hover { background: var(--surface-2); }
.sr-title { font-size: 14px; }
.sr-title mark { background: var(--accent-soft); color: var(--accent); padding: 0 2px; border-radius: 3px; }
.sr-sub { font-size: 12px; color: var(--text-3); }
.sr-empty { padding: 16px; text-align: center; color: var(--text-3); font-size: 13px; }

/* ---------- 布局 ---------- */
.app { max-width: 1080px; margin: 0 auto; padding: 22px 20px 60px; }
.foot { max-width: 1080px; margin: 0 auto; padding: 20px; font-size: 12px; color: var(--text-3); text-align: center; }
.foot p { margin: 0 0 4px; line-height: 1.7; }
.foot code { font-family: var(--mono); font-size: 11px; background: var(--surface-2); padding: 0 4px; border-radius: 3px; }

.page-title { font-size: 20px; font-weight: 500; margin: 0 0 4px; }
.page-sub { font-size: 14px; color: var(--text-2); margin: 0 0 22px; }
.crumb { font-size: 13px; color: var(--text-3); margin-bottom: 14px; }
.crumb a:hover { color: var(--accent); }

.section-head { display: flex; align-items: baseline; gap: 10px; margin: 30px 0 14px; }
.section-head h2 { font-size: 16px; font-weight: 500; margin: 0; }
.section-head .hint { font-size: 12px; color: var(--text-3); }

/* ---------- 学科卡 ---------- */
.subject-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(212px, 1fr)); gap: 12px; }
.subject-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  transition: transform .12s, border-color .15s, box-shadow .15s;
}
.subject-card:hover { transform: translateY(-2px); border-color: var(--border-strong); box-shadow: var(--shadow); }
.sc-top { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.sc-icon {
  width: 34px; height: 34px; border-radius: 9px;
  display: grid; place-items: center; flex-shrink: 0;
}
.sc-name { font-size: 15px; font-weight: 500; }
.sc-grade { font-size: 11px; color: var(--text-3); }
.sc-desc { font-size: 12px; color: var(--text-2); line-height: 1.55; margin-bottom: 12px; min-height: 34px; }
.sc-bar { height: 4px; border-radius: 2px; background: var(--surface-2); overflow: hidden; }
.sc-bar > i { display: block; height: 100%; background: var(--accent); border-radius: 2px; transition: width .3s; }
.sc-meta { display: flex; justify-content: space-between; font-size: 11px; color: var(--text-3); margin-top: 6px; }

/* ---------- 章节列表 ---------- */
.chapter-list { display: grid; gap: 10px; }
.chapter {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 15px 17px;
}
.ch-top { display: flex; align-items: center; gap: 10px; }
.ch-name { font-size: 15px; font-weight: 500; flex: 1; }
.ch-grade { font-size: 12px; color: var(--text-3); }
.ch-summary { font-size: 13px; color: var(--text-2); margin: 6px 0 0; line-height: 1.6; }
.ch-foot { display: flex; align-items: center; gap: 14px; margin-top: 11px; font-size: 12px; color: var(--text-3); }
.ch-actions { display: flex; gap: 8px; margin-top: 12px; }

.btn {
  padding: 5px 12px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--text);
  font-size: 13px;
  transition: background .15s, border-color .15s, color .15s;
}
.btn:hover { background: var(--surface-2); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { opacity: .88; background: var(--accent); }
.btn.sm { padding: 3px 9px; font-size: 12px; }
.btn:disabled { opacity: .45; cursor: not-allowed; }

/* ---------- 知识点 ---------- */
.point {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
}
.p-head {
  display: flex; align-items: center; gap: 11px;
  padding: 14px 17px;
}
.p-title { font-size: 15px; font-weight: 500; flex: 1; cursor: pointer; }
.badge {
  font-size: 11px; padding: 1px 7px; border-radius: 20px;
  border: 1px solid var(--border-strong); color: var(--text-3);
}
.badge.lv1 { color: var(--bad); border-color: var(--bad); background: var(--bad-soft); }
.badge.lv2 { color: var(--warn); border-color: var(--warn); }
.badge.lv3 { color: var(--text-3); }
.star {
  background: none; border: none; font-size: 17px; line-height: 1;
  color: var(--text-3); padding: 2px; transition: color .15s, transform .15s;
}
.star:hover { transform: scale(1.15); }
.star.on { color: var(--warn); }
.p-body { padding: 0 17px 16px; border-top: 1px solid var(--border); }
.p-content { font-size: 14px; line-height: 1.8; white-space: pre-wrap; margin: 14px 0; }
.p-block { margin-top: 14px; }
.p-block > h4 {
  font-size: 12px; font-weight: 500; color: var(--text-3);
  margin: 0 0 7px; text-transform: none; letter-spacing: .04em;
}
.formula {
  font-family: var(--mono); font-size: 13.5px;
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 9px 13px; margin: 5px 0;
  overflow-x: auto; white-space: pre-wrap; line-height: 1.6;
}
.tips { list-style: none; padding: 0; margin: 0; }
.tips li {
  position: relative; padding: 5px 0 5px 18px;
  font-size: 13.5px; color: var(--text-2); line-height: 1.65;
}
.tips li::before {
  content: ""; position: absolute; left: 3px; top: 12px;
  width: 5px; height: 5px; border-radius: 50%; background: var(--warn);
}
.p-foot { display: flex; gap: 8px; margin-top: 16px; padding-top: 13px; border-top: 1px dashed var(--border); }

/* ---------- 题目 ---------- */
.quiz-wrap { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 17px; }
.quiz-head { display: flex; align-items: center; gap: 10px; margin-bottom: 15px; }
.quiz-head h3 { font-size: 15px; font-weight: 500; margin: 0; flex: 1; }
.quiz-prog { font-size: 12px; color: var(--text-3); }
.q {
  padding: 14px 0;
  border-top: 1px solid var(--border);
}
.q:first-of-type { border-top: none; }
.q-stem { font-size: 14.5px; line-height: 1.75; margin-bottom: 10px; }
.q-opts { display: grid; gap: 6px; }
.q-opt {
  display: flex; align-items: flex-start; gap: 9px;
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 14px;
  text-align: left;
  background: transparent;
  color: var(--text);
  transition: background .12s, border-color .12s;
}
.q-opt:hover { background: var(--surface-2); }
.q-opt .k {
  flex-shrink: 0; width: 19px; height: 19px; border-radius: 50%;
  border: 1px solid var(--border-strong);
  display: grid; place-items: center; font-size: 11px; color: var(--text-3);
}
.q-opt.sel { border-color: var(--accent); background: var(--accent-soft); }
.q-opt.sel .k { border-color: var(--accent); color: var(--accent); }
.q-opt.right { border-color: var(--ok); background: var(--ok-soft); }
.q-opt.right .k { border-color: var(--ok); color: var(--ok); }
.q-opt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.q-opt.wrong .k { border-color: var(--bad); color: var(--bad); }
.q-fill {
  width: 100%; height: 36px; padding: 0 12px;
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: var(--bg); color: var(--text); font-family: var(--font); font-size: 14px;
  outline: none;
}
.q-fill:focus { border-color: var(--accent); }
.q-actions { display: flex; gap: 8px; margin-top: 11px; }
.q-exp {
  margin-top: 11px; padding: 11px 13px;
  background: var(--surface-2); border-radius: var(--radius-sm);
  border-left: 3px solid var(--accent);
  font-size: 13.5px; line-height: 1.75; color: var(--text-2);
}
.q-exp b { color: var(--text); font-weight: 500; }
.q-credit { font-size: 11px; color: var(--text-3); margin-top: 8px; padding-left: 2px; line-height: 1.6; }
.paper-credit { margin-top: 22px; padding-top: 14px; border-top: 1px solid #d8dae0; font-size: 11.5px; color: #8b909c; }
.paper-credit b { color: #5c6270; font-weight: 500; }
.paper-credit ul { margin: 6px 0 0; padding-left: 18px; }
.score-line { font-size: 14px; margin-left: auto; }
.score-line b { font-size: 16px; }

/* ---------- 统计 ---------- */
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; margin-bottom: 26px; }
.stat {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 16px;
}
.stat-n { font-size: 26px; font-weight: 500; line-height: 1.2; }
.stat-l { font-size: 12px; color: var(--text-3); margin-top: 2px; }

.empty { text-align: center; padding: 50px 20px; color: var(--text-3); }
.empty svg { opacity: .35; margin-bottom: 10px; }
.empty p { margin: 0; font-size: 14px; }

.accordion-head { display: flex; align-items: center; gap: 10px; margin: 26px 0 12px; cursor: pointer; }
.accordion-head h2 { font-size: 16px; font-weight: 500; margin: 0; flex: 1; }
.arrow { transition: transform .2s; color: var(--text-3); }
.accordion-head.open .arrow { transform: rotate(90deg); }

mark { background: var(--accent-soft); color: var(--accent); padding: 0 2px; border-radius: 3px; }

/* ---------- 组卷 ---------- */
.paper-layout { display: grid; grid-template-columns: 250px 1fr; gap: 18px; align-items: start; }
.paper-side {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  position: sticky;
  top: 108px;
  max-height: calc(100vh - 128px);
  overflow-y: auto;
}
.pf-block { margin-bottom: 16px; }
.pf-block:last-child { margin-bottom: 0; }
.pf-label { display: block; font-size: 12px; color: var(--text-3); margin-bottom: 6px; }
.pf-select, .pf-input {
  width: 100%;
  height: 32px;
  padding: 0 9px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg);
  color: var(--text);
  font-size: 13px;
  font-family: inherit;
  outline: none;
}
.pf-select:focus, .pf-input:focus { border-color: var(--accent); }
.pf-checks { display: flex; flex-wrap: wrap; gap: 10px; }
.pf-check { display: flex; align-items: center; gap: 5px; font-size: 13px; color: var(--text-2); cursor: pointer; }
.pf-check input { accent-color: var(--accent); margin: 0; }
.pf-points { display: grid; gap: 4px; max-height: 190px; overflow-y: auto; }
.pf-point { line-height: 1.4; }
.pf-point span { font-size: 12.5px; }
.pf-hint { font-size: 11px; color: var(--text-3); margin: 5px 0 0; line-height: 1.5; }

.pf-bar {
  display: flex; align-items: center; gap: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 11px 15px;
  margin-bottom: 12px;
  position: sticky;
  top: 108px;
  z-index: 10;
}
.pf-count { font-size: 13px; color: var(--text-2); flex: 1; }
.pf-count b { color: var(--text); font-size: 15px; }
.pf-bar-actions { display: flex; gap: 7px; }

.pf-list { display: grid; gap: 8px; }
.pf-item {
  display: flex; gap: 11px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 13px 15px;
  cursor: pointer;
  transition: border-color .12s, background .12s;
}
.pf-item:hover { border-color: var(--border-strong); }
.pf-item.on { border-color: var(--accent); background: var(--accent-soft); }
.pf-item input { accent-color: var(--accent); margin-top: 3px; flex-shrink: 0; }
.pf-item-main { flex: 1; min-width: 0; }
.pf-stem { font-size: 13.5px; line-height: 1.6; }
.pf-opts { display: flex; flex-wrap: wrap; gap: 6px 14px; margin-top: 5px; font-size: 12.5px; color: var(--text-2); }
.pf-tags { display: flex; flex-wrap: wrap; gap: 5px; margin-top: 7px; }
.pf-tag {
  font-size: 11px; padding: 1px 7px; border-radius: 20px;
  background: var(--surface-2); color: var(--text-3); border: 1px solid var(--border);
}
.pf-tag.lv1 { color: var(--ok); border-color: var(--ok); }
.pf-tag.lv2 { color: var(--warn); border-color: var(--warn); }
.pf-tag.lv3 { color: var(--bad); border-color: var(--bad); }

/* ---------- 试卷预览 ---------- */
.modal {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(0, 0, 0, .45);
  display: flex; align-items: center; justify-content: center;
  padding: 20px;
}
.modal[hidden] { display: none; }
.modal-box {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  width: min(860px, 100%);
  max-height: 92vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}
.modal-head { display: flex; gap: 10px; align-items: center; padding: 13px 16px; border-bottom: 1px solid var(--border); }
.pf-title-input { flex: 1; height: 36px; font-size: 15px; }
.modal-tools {
  display: flex; align-items: center; gap: 16px;
  padding: 10px 16px; border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}
.modal-body { flex: 1; overflow-y: auto; padding: 20px; background: var(--surface-2); }
.modal-foot { padding: 12px 16px; border-top: 1px solid var(--border); display: flex; justify-content: flex-end; }

.paper-sheet {
  background: #fff; color: #16181d;
  padding: 34px 40px;
  border-radius: 8px;
  max-width: 760px;
  margin: 0 auto;
  line-height: 1.85;
}
.paper-head { text-align: center; border-bottom: 1px solid #d8dae0; padding-bottom: 14px; margin-bottom: 22px; }
.paper-head h1 { font-size: 19px; font-weight: 500; margin: 0 0 12px; }
.paper-meta { display: flex; justify-content: space-between; font-size: 12px; color: #5c6270; flex-wrap: wrap; gap: 10px; }
.paper-sec { margin-bottom: 26px; }
.paper-sec h2 { font-size: 14.5px; font-weight: 500; margin: 0 0 12px; }
.paper-qs { list-style: none; padding: 0; margin: 0; }
.pq { margin-bottom: 15px; break-inside: avoid; }
.pq-stem { font-size: 14px; }
.pq-opts { margin: 6px 0 0 20px; display: grid; grid-template-columns: repeat(2, 1fr); gap: 2px 16px; font-size: 13.5px; }
.pq-blank { height: 30px; border-bottom: 1px solid #d8dae0; margin: 6px 0 0 20px; }
.paper-answers { border-top: 2px solid #d8dae0; padding-top: 18px; break-before: page; }
.paper-ans-list { font-size: 13.5px; padding-left: 20px; }
.paper-ans-list li { margin-bottom: 11px; }
.paper-ans-exp { color: #5c6270; font-size: 12.5px; margin-top: 3px; }
.paper-foot { border-top: 1px solid #d8dae0; padding-top: 12px; text-align: center; font-size: 11.5px; color: #8b909c; }

@media print {
  .topbar, .searchbar, .foot, .paper-side, .pf-list, .pf-bar, .modal-head, .modal-tools, .modal-foot { display: none !important; }
  .modal { position: static; background: none; padding: 0; display: block; }
  .modal-box { border: none; max-height: none; }
  .modal-body { overflow: visible; padding: 0; background: #fff; }
  .paper-sheet { box-shadow: none; max-width: 100%; padding: 0; }
  .paper-answers { break-before: page; }
}

@media (max-width: 820px) {
  .paper-layout { grid-template-columns: 1fr; }
  .paper-side, .pf-bar { position: static; max-height: none; }
  .pf-bar { position: static; }
  .pq-opts { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .topnav a { padding: 6px 8px; font-size: 13px; }
  .app { padding: 16px 14px 50px; }
  .topbar-inner, .searchbar-inner { padding: 0 14px; }
  .searchbar { top: 54px; }
  .search-icon { left: 27px; }
  .search-results { left: 14px; right: 14px; }
  .brand span { display: none; }
}

/* ---------- 智能解题 ---------- */
.solve-wrap { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; align-items: start; }
.solve-input { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; }
.solve-row { display: flex; gap: 10px; margin-bottom: 12px; }
.solve-row .pf-select { flex: 1; }
.slv-text {
  width: 100%; min-height: 130px; resize: vertical;
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: var(--bg); color: var(--text); font-size: 14px; line-height: 1.7;
  font-family: inherit; padding: 11px 13px; outline: none; box-sizing: border-box;
}
.slv-text:focus { border-color: var(--accent); }
.slv-drop {
  margin-top: 12px; border: 1.5px dashed var(--border-strong); border-radius: var(--radius);
  padding: 18px; text-align: center; color: var(--text-3); cursor: pointer;
  transition: border-color .12s, background .12s;
}
.slv-drop.on, .slv-drop:hover { border-color: var(--accent); background: var(--accent-soft); }
.slv-drop-inner svg { color: var(--text-3); margin-bottom: 6px; }
.slv-drop-inner p { font-size: 12.5px; margin: 0; }
.slv-preview { position: relative; margin-top: 12px; }
.slv-preview img { width: 100%; border-radius: var(--radius-sm); border: 1px solid var(--border); display: block; }
.slv-preview .icon-btn {
  position: absolute; top: 6px; right: 6px; background: rgba(0,0,0,.5); color: #fff;
  border: none; width: 26px; height: 26px; border-radius: 50%; cursor: pointer; font-size: 13px;
}
.slv-actions { display: flex; align-items: center; gap: 10px; margin-top: 14px; }
.slv-hint { font-size: 11.5px; color: var(--text-3); }

.solve-output { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; min-height: 200px; }
.slv-loading { display: flex; align-items: center; gap: 10px; color: var(--text-2); font-size: 13.5px; }
.spin { width: 16px; height: 16px; border: 2px solid var(--border-strong); border-top-color: var(--accent); border-radius: 50%; animation: slvspin .7s linear infinite; }
@keyframes slvspin { to { transform: rotate(360deg); } }
.slv-err { color: var(--bad); font-size: 13.5px; line-height: 1.7; }
.slv-err code { background: var(--surface-2); padding: 1px 5px; border-radius: 4px; }
.slv-answer-head { font-size: 12px; color: var(--text-3); margin-bottom: 10px; border-bottom: 1px solid var(--border); padding-bottom: 8px; }
.slv-md { font-size: 14px; line-height: 1.8; color: var(--text); }
.slv-md h3, .slv-md h4, .slv-md h5, .slv-md h6 { margin: 14px 0 6px; line-height: 1.4; }
.slv-md h3 { font-size: 15.5px; } .slv-md h4 { font-size: 14.5px; }
.slv-md p { margin: 8px 0; }
.slv-md ul { margin: 8px 0; padding-left: 22px; }
.slv-md li { margin: 4px 0; }
.slv-md code { background: var(--surface-2); padding: 1px 5px; border-radius: 4px; font-size: 12.5px; }
.slv-md pre { background: var(--bg); border: 1px solid var(--border); border-radius: 6px; padding: 10px 12px; overflow-x: auto; font-size: 12.5px; }
.slv-md .math { font-style: italic; color: var(--accent); }
.slv-md hr { border: none; border-top: 1px solid var(--border); margin: 12px 0; }

@media (max-width: 820px) {
  .solve-wrap { grid-template-columns: 1fr; }
}