:root{
  --bg:#F6F4F0; --card:#fff; --ink:#1C1917; --ink2:#78716C; --ink3:#A8A29E;
  --line:#E8E4DC; --brand:#2563EB; --brand-soft:#EFF4FF;
  --yw:#E11D48; --sx:#2563EB; --yy:#7C3AED; --kx:#059669;
  --ok:#059669; --doing:#D97706; --todo:#A8A29E;
  --r:14px; --sh:0 1px 2px rgba(28,25,23,.05), 0 8px 24px -16px rgba(28,25,23,.18);
  --safe: env(safe-area-inset-bottom, 0px);
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0; background:var(--bg); color:var(--ink);
  font:15px/1.65 -apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  -webkit-font-smoothing:antialiased;
}
button{font-family:inherit}
a{color:inherit;text-decoration:none}
.boot{padding:48px 20px;text-align:center;color:var(--ink2)}

.app{min-height:100dvh;display:flex;flex-direction:column}
.top{
  position:sticky;top:0;z-index:20;background:rgba(246,244,240,.92);
  backdrop-filter:saturate(1.4) blur(12px);border-bottom:1px solid var(--line);
}
.top-in{max-width:880px;margin:0 auto;padding:12px 18px;display:flex;align-items:center;gap:12px}
.brand{font-weight:700;font-size:16px;letter-spacing:-.01em;display:flex;align-items:center;gap:8px}
.brand .dot{width:10px;height:10px;border-radius:50%;background:var(--brand);box-shadow:0 0 0 4px var(--brand-soft)}
.top-actions{margin-left:auto;display:flex;gap:8px;align-items:center}
.main{flex:1;width:100%;max-width:880px;margin:0 auto;padding:18px 18px 96px}

.bottom{
  position:fixed;left:0;right:0;bottom:0;z-index:35;
  background:rgba(255,255,255,.96);border-top:1px solid var(--line);
  padding:8px 12px calc(8px + var(--safe));
}
.bottom-in{max-width:880px;margin:0 auto;display:grid;grid-template-columns:repeat(3,1fr);gap:4px}
.tab{
  appearance:none;border:0;background:transparent;color:var(--ink3);
  padding:8px 4px;border-radius:12px;font-size:11px;font-weight:600;
  display:flex;flex-direction:column;align-items:center;gap:3px;cursor:pointer;
}
.tab .ic{font-size:18px;line-height:1}
.tab.active{color:var(--brand);background:var(--brand-soft)}

.card{
  background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  box-shadow:var(--sh);padding:16px;
}
.stack{display:grid;gap:12px}
.row{display:flex;gap:12px;align-items:center}
.row.between{justify-content:space-between}
.muted{color:var(--ink2)}
.tiny{font-size:12px}
.strong{font-weight:700}

.kicker{
  display:inline-flex;align-items:center;gap:6px;
  font-size:11.5px;font-weight:700;letter-spacing:.04em;color:var(--brand);
  background:var(--brand-soft);border-radius:999px;padding:4px 10px;
}
h1,h2,h3{margin:0;letter-spacing:-.02em;line-height:1.25}
h1{font-size:26px}
h2{font-size:19px}
h3{font-size:16px}

.btn{
  appearance:none;border:1px solid transparent;border-radius:12px;
  padding:11px 16px;font-size:14px;font-weight:650;cursor:pointer;
  background:var(--brand);color:#fff;min-height:44px;
}
.btn:disabled{opacity:.55;cursor:not-allowed}
.btn.ghost{background:#fff;border-color:var(--line);color:var(--ink)}
.btn.soft{background:var(--brand-soft);color:var(--brand)}
.btn.block{width:100%}
.btn.danger{background:#fff1f2;color:#be123c;border-color:#fecdd3}

.field{display:grid;gap:6px;margin-bottom:12px}
.field label{font-size:12px;font-weight:700;color:var(--ink2)}
.field input,.field select,.field textarea{
  width:100%;border:1px solid var(--line);border-radius:12px;
  padding:12px 12px;font-size:16px;background:#fff;color:var(--ink);
}
.field input:focus,.field select:focus{outline:2px solid var(--brand-soft);border-color:var(--brand)}

.hint-box{
  background:var(--brand-soft);border:1px solid #dce7ff;border-radius:12px;padding:12px;
}

.progress-ring{
  --p:0; --c:var(--brand);
  width:92px;height:92px;border-radius:50%;
  background:conic-gradient(var(--c) calc(var(--p)*1%), var(--line) 0);
  display:grid;place-items:center;flex:0 0 auto;
}
.progress-ring .inner{
  width:72px;height:72px;border-radius:50%;background:#fff;
  display:grid;place-items:center;font-weight:800;font-size:18px;
}
.bar{height:8px;border-radius:99px;background:var(--line);overflow:hidden}
.bar > i{display:block;height:100%;border-radius:99px;background:var(--brand)}
.bar > i.bar-a{background:var(--sx)}
.bar > i.bar-b{background:#ea580c}

.subject-chip{
  display:inline-flex;align-items:center;gap:6px;
  font-size:11px;font-weight:700;padding:3px 8px;border-radius:999px;
}
.sub-chinese{color:var(--yw);background:#fff1f2}
.sub-math{color:var(--sx);background:#eff6ff}
.sub-english{color:var(--yy);background:#f5f3ff}
.sub-science{color:var(--kx);background:#ecfdf5}

.type-tag{
  font-size:10px;font-weight:800;padding:2px 7px;border-radius:6px;letter-spacing:.03em;
}
.type-A{background:#eff6ff;color:#1d4ed8}
.type-B{background:#fff7ed;color:#c2410c}
.type-words{background:#f5f3ff;color:#6d28d9}

.grade-badge{
  display:inline-flex;align-items:center;
  font-size:11px;font-weight:800;letter-spacing:.02em;
  padding:3px 9px;border-radius:999px;
  background:#1C1917;color:#fff;
}

.gap-item{
  width:100%;text-align:left;cursor:pointer;border:1px solid var(--line);
  background:#fff;border-radius:12px;padding:13px 14px;display:grid;gap:8px;
}
.gap-item:active{transform:scale(.995)}
.gap-item .title{font-weight:650;font-size:14.5px;line-height:1.4}
.status-dot{width:8px;height:8px;border-radius:50%;flex:0 0 auto}
.st-todo{background:var(--todo)}
.st-doing{background:var(--doing)}
.st-done{background:var(--ok)}

.pill{
  border:1px solid var(--line);background:#fff;border-radius:999px;
  padding:7px 12px;font-size:12px;font-weight:650;color:var(--ink2);cursor:pointer;
  white-space:nowrap;
}
.pill.on{background:var(--brand);border-color:var(--brand);color:#fff}

.switch-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:8px}
.switch-cell{
  border:1px solid var(--line);background:#fff;border-radius:12px;
  padding:12px 6px;text-align:center;cursor:pointer;min-height:64px;
}
.switch-cell.on{border-color:var(--brand);background:var(--brand-soft);color:var(--brand);font-weight:700}
.switch-cell .n{font-size:18px;font-weight:800;line-height:1.1}
.switch-cell .t{font-size:10px;color:var(--ink3);margin-top:2px}
.switch-cell.on .t{color:var(--brand)}

.hero{
  background:
    radial-gradient(700px 220px at 10% -20%, #e8eefc 0%, transparent 60%),
    radial-gradient(500px 200px at 90% 0%, #fde8e8 0%, transparent 55%),
    #fff;
  border:1px solid var(--line);border-radius:18px;padding:22px 18px;
}

.list-head{padding:14px 16px}
.filters-compact{display:grid;gap:8px}

.detail-section{border-top:1px solid var(--line);padding:14px 0}
.detail-section:first-child{border-top:0;padding-top:0}
.detail-section h3{margin-bottom:8px;font-size:14px;color:var(--brand)}
.detail-body{color:var(--ink);font-size:14px}
.detail-body p{margin:0 0 8px}
.detail-body ul,.detail-body ol{margin:0 0 8px;padding-left:1.2em}
.detail-body li{margin:4px 0}
.detail-body blockquote{
  margin:8px 0;padding:8px 12px;border-left:3px solid var(--brand);
  background:var(--brand-soft);border-radius:0 8px 8px 0;
}
.detail-body pre,.detail-body code{
  white-space:pre-wrap;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12.5px;
}
.detail-actions{position:sticky;bottom:calc(12px + var(--safe))}

.toast{
  position:fixed;left:50%;transform:translateX(-50%);bottom:calc(84px + var(--safe));
  background:#1C1917;color:#fff;padding:10px 16px;border-radius:999px;font-size:13px;
  z-index:100;opacity:0;pointer-events:none;transition:opacity .2s;
}
.toast.show{opacity:1}

.empty{
  text-align:center;padding:36px 18px;color:var(--ink2);
  border:1px dashed var(--line);border-radius:var(--r);background:#fff;
}

.tabs-row{display:flex;gap:8px;overflow-x:auto;padding-bottom:2px;-webkit-overflow-scrolling:touch}
.tabs-row::-webkit-scrollbar{display:none}
.stats-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}
.stat{
  background:#fff;border:1px solid var(--line);border-radius:12px;padding:12px;text-align:center;
}
.stat .v{font-size:22px;font-weight:800;letter-spacing:-.03em}
.stat .k{font-size:11px;color:var(--ink2);margin-top:2px}

.child-card{cursor:pointer}
.child-card:hover{border-color:#cfd7ea}

.prog-row + .prog-row{margin-top:2px}

@media (min-width:820px){
  h1{font-size:30px}
  .main{padding-top:28px}
}

.subject-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:12px}
.subject-entry{
  text-align:left;cursor:pointer;border:1px solid var(--line);background:#fff;
  border-radius:12px;padding:12px;
}
.subject-entry:active{transform:scale(.995)}
@media (min-width:820px){
  .subject-grid{grid-template-columns:repeat(4,1fr)}
}

/* ---- account / me ---- */
.wechat-btn{background:#07C160;color:#fff}
.wechat-btn:hover{background:#06ad56}
.wx-icon{
  display:inline-grid;place-items:center;width:22px;height:22px;border-radius:6px;
  background:#fff;color:#07C160;font-size:12px;font-weight:800;margin-right:6px;
}
.login-split{
  display:flex;align-items:center;gap:10px;color:var(--ink3);font-size:11px;
  margin:16px 0 12px;
}
.login-split::before,.login-split::after{
  content:"";flex:1;height:1px;background:var(--line);
}
.link{color:var(--brand);font-weight:600}

.profile-card .avatar{
  width:56px;height:56px;border-radius:16px;background:var(--brand);
  color:#fff;display:grid;place-items:center;font-size:22px;font-weight:800;flex:0 0 auto;
}
.menu-list{margin-top:6px}
.menu-item{
  width:100%;display:flex;align-items:center;justify-content:space-between;gap:12px;
  padding:13px 2px;border:0;border-top:1px solid var(--line);background:transparent;
  text-align:left;cursor:pointer;font-family:inherit;
}
.menu-list .menu-item:first-child{border-top:0}
.menu-title{font-size:14.5px;font-weight:650}
.chev{color:var(--ink3);font-size:18px;line-height:1}
.menu-item:active{opacity:.7}

textarea,input[type=password]{
  width:100%;border:1px solid var(--line);border-radius:12px;
  padding:12px;font-size:16px;background:#fff;color:var(--ink);font-family:inherit;
}
select{
  width:100%;border:1px solid var(--line);border-radius:12px;
  padding:12px;font-size:16px;background:#fff;color:var(--ink);
}

/* ---- knowledge hub ---- */
.path-list{display:grid;gap:10px}
.path-item{
  display:flex;gap:12px;align-items:flex-start;text-align:left;
  border:1px solid var(--line);background:#fff;border-radius:14px;
  padding:14px;cursor:pointer;
}
.path-item:active{transform:scale(.995)}
.path-num{
  width:28px;height:28px;border-radius:50%;background:var(--brand-soft);color:var(--brand);
  display:grid;place-items:center;font-size:13px;font-weight:800;flex:0 0 auto;
}
.level-tag{
  font-size:10px;font-weight:700;padding:2px 8px;border-radius:999px;
  background:#f5f5f4;color:var(--ink2);
}
.subject-entry .subject-chip.sub-chinese{color:var(--yw);background:#fff1f2}
.subject-entry .subject-chip.sub-math{color:var(--sx);background:#eff6ff}
.subject-entry .subject-chip.sub-english{color:var(--yy);background:#f5f3ff}
.subject-entry .subject-chip.sub-science{color:var(--kx);background:#ecfdf5}

/* ---- knowledge reader ---- */
.reader{display:grid;gap:14px;padding-bottom:120px}
.reader-hero{
  background:
    radial-gradient(600px 180px at 12% -20%, #e8eefc 0%, transparent 60%),
    radial-gradient(420px 160px at 90% 0%, #f3e8ff 0%, transparent 55%),
    #fff;
  border:1px solid var(--line);border-radius:18px;padding:18px 16px 20px;
}
.reader-title{
  margin:12px 0 8px;font-size:24px;line-height:1.28;letter-spacing:-.025em;
}
.reader-sub{margin:0;color:var(--ink2);font-size:13.5px;line-height:1.6}

.toc-rail{
  position:fixed;left:0;right:0;
  bottom:calc(64px + env(safe-area-inset-bottom, 0px));
  z-index:25;
  background:rgba(255,255,255,.96);
  backdrop-filter:saturate(1.4) blur(12px);
  -webkit-backdrop-filter:saturate(1.4) blur(12px);
  border-top:1px solid var(--line);
  box-shadow:0 -8px 24px -16px rgba(28,25,23,.18);
  padding:10px 0 calc(10px + env(safe-area-inset-bottom, 0px));
  pointer-events:none; /* 仅子级可交互，避免挡住点选 */
}
.toc-track{
  pointer-events:auto;
  display:flex;gap:8px;align-items:center;
  overflow-x:auto;overflow-y:hidden;
  padding:2px 28px;margin:0 6px;
  scroll-behavior:smooth;
  -webkit-overflow-scrolling:touch;
  scrollbar-width:none;
  touch-action:pan-x;
  user-select:none;
  -webkit-user-select:none;
}
.toc-track::-webkit-scrollbar{display:none}
.toc-chip{
  flex:0 0 auto;display:inline-flex;align-items:center;gap:6px;
  border:1px solid var(--line);
  background:#fff;
  color:var(--ink2);border-radius:999px;
  padding:8px 12px;font-size:12px;font-weight:650;
  cursor:pointer;font-family:inherit;white-space:nowrap;
  box-shadow:0 1px 2px rgba(28,25,23,.06);
  max-width:220px;
  touch-action:manipulation;
}
.toc-chip-t{overflow:hidden;text-overflow:ellipsis}
.toc-chip-n{
  width:18px;height:18px;border-radius:50%;background:var(--line);
  color:var(--ink2);font-size:10px;font-weight:800;
  display:grid;place-items:center;flex:0 0 auto;
}
.toc-chip.on{
  background:var(--brand);border-color:var(--brand);color:#fff;
}
.toc-chip.on .toc-chip-n{background:rgba(255,255,255,.22);color:#fff}
.toc-chip-l3{opacity:.92}
.toc-fade{
  position:absolute;top:0;bottom:0;width:36px;pointer-events:none;opacity:0;
  transition:opacity .2s;
}
.toc-fade.left{left:0;background:linear-gradient(to right, rgba(255,255,255,.98), transparent)}
.toc-fade.right{right:0;background:linear-gradient(to left, rgba(255,255,255,.98), transparent)}
.toc-rail.fade-l .toc-fade.left{opacity:1}
.toc-rail.fade-r .toc-fade.right{opacity:1}

.reader-body{padding:18px 16px 22px;overflow:hidden}
.doc-h1{font-size:20px;margin:8px 0 12px;letter-spacing:-.02em}
.doc-h2{
  font-size:17px;margin:26px 0 12px;padding-top:14px;border-top:1px solid var(--line);
  letter-spacing:-.015em;
}
.doc-h2:first-child{margin-top:0;padding-top:0;border-top:0}
.doc-h3{font-size:15px;margin:18px 0 10px;color:var(--ink)}
.reader-body p{margin:0 0 10px;font-size:14.5px;line-height:1.75;color:var(--ink)}
.doc-ul{margin:0 0 12px;padding-left:1.25em}
.doc-ul li{margin:5px 0;font-size:14px;line-height:1.7}
.doc-hr{border:0;border-top:1px dashed var(--line);margin:18px 0}
.book-title{color:var(--brand);font-weight:650}
.doc-ref{
  color:var(--brand);font-weight:650;
  text-decoration:underline;text-underline-offset:3px;
  text-decoration-color:rgba(37,99,235,.35);
}
.doc-ref:active{opacity:.75}
.doc-pre{
  background:#1e293b;color:#f1f5f9;border-radius:12px;padding:14px;
  overflow:auto;font-size:12px;line-height:1.55;margin:12px 0;
}
.doc-pre code,.doc-pre strong,.doc-pre em{
  color:#f1f5f9;background:transparent;padding:0;font-weight:400;
}
.reader-body code{
  background:#f4f4f5;color:#292524;padding:1px 6px;border-radius:6px;
  font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:12px;
}
.reader-body pre code{color:inherit;background:transparent}
/* 防止深色块内出现黑字 */
.doc-pre *,.reader-body pre *{color:inherit}
.reader-body pre{
  background:#1e293b;color:#f1f5f9;border-radius:12px;padding:14px;
  overflow:auto;font-size:12px;line-height:1.55;margin:12px 0;
}
.reader-body blockquote{
  margin:12px 0;padding:12px 14px;border-left:3px solid var(--brand);
  background:var(--brand-soft);border-radius:0 12px 12px 0;
  font-size:13.5px;line-height:1.7;color:var(--ink);
}
.table-wrap{
  overflow-x:auto;margin:12px 0;border:1px solid var(--line);border-radius:12px;
  -webkit-overflow-scrolling:touch;
}
.doc-table{border-collapse:collapse;width:100%;min-width:480px;font-size:12.5px}
.doc-table th{
  background:#fafaf9;color:var(--ink2);font-weight:700;text-align:left;
  padding:9px 10px;border-bottom:1px solid var(--line);white-space:nowrap;
}
.doc-table td{
  padding:8px 10px;border-bottom:1px solid var(--line);vertical-align:top;
  line-height:1.55;color:var(--ink);
}
.doc-table tr:last-child td{border-bottom:0}
.doc-table tbody tr:nth-child(even){background:#fcfcfb}

.reader-nav{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.reader-nav-btn{
  border:1px solid var(--line);background:#fff;border-radius:14px;padding:12px 14px;
  text-align:left;cursor:pointer;font-family:inherit;
}
.reader-nav-btn.primary{
  background:var(--brand);border-color:var(--brand);color:#fff;
}
.reader-nav-btn.primary .tiny{color:#fff}
.reader-nav-btn:active{transform:scale(.99)}

@media (min-width:820px){
  .reader-title{font-size:28px}
  .reader-body{padding:24px 28px}
  .reader-hero{padding:22px 24px}
}

.modal-mask{
  position:fixed;inset:0;background:rgba(28,25,23,.45);z-index:200;
  display:grid;place-items:center;padding:20px;
}
.modal-card{
  width:min(420px, 100%);background:#fff;border-radius:16px;padding:18px;
  box-shadow:0 20px 50px rgba(28,25,23,.25);
}
.modal-card h3{margin:0 0 8px}

/* 手机号 + 验证码：一体输入行，禁止换行 */
.input-btn{
  display:flex;align-items:stretch;gap:0;width:100%;
  border:1px solid var(--line);border-radius:12px;background:#fff;
  overflow:hidden;
}
.input-btn:focus-within{border-color:var(--brand);box-shadow:0 0 0 3px var(--brand-soft)}
.input-btn > input{
  flex:1 1 auto;min-width:0;width:100%;
  border:0;outline:0;background:transparent;
  padding:12px 12px;font-size:16px;color:var(--ink);
}
.input-btn > input:focus{outline:0}
.input-btn > button{
  flex:0 0 auto;width:104px;min-height:46px;
  border:0;border-left:1px solid var(--line);
  background:var(--brand-soft);color:var(--brand);
  font-size:13px;font-weight:700;white-space:nowrap;
  cursor:pointer;font-family:inherit;
}
.input-btn > button:disabled{opacity:.55;cursor:not-allowed;background:#f5f5f4;color:var(--ink3)}
.input-btn > button:not(:disabled):active{background:#dbeafe}