:root {
  --paper: #f6f0e3; --paper-2: #fbf7ee; --ink: #26211c; --ink-2: #6b6256; --line: #e2d8c3;
  --cinnabar: #b3261e; --cinnabar-d: #8f1d17; --jade: #3f6b57; --gold: #b58b3c;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--paper); color: var(--ink);
  font-family: "Songti SC", "Noto Serif CJK SC", "Source Han Serif SC", "STSong", "SimSun", serif;
  line-height: 1.85; font-size: 17px;
  background-image: radial-gradient(rgba(120,90,40,.05) 1px, transparent 1px); background-size: 6px 6px;
}
.wrap { max-width: 640px; margin: 0 auto; padding: 20px 18px 96px; }
h1.title { font-size: 28px; letter-spacing: .25em; margin: 18px 0 4px; font-weight: 700; }
.sub { color: var(--ink-2); font-size: 14px; margin: 0 0 20px; }
.seal { display: inline-block; background: var(--cinnabar); color: #fff; font-size: 13px; padding: 0 8px; border-radius: 3px; letter-spacing: .1em; margin-right: 8px; vertical-align: middle; }
.card { background: var(--paper-2); border: 1px solid var(--line); border-radius: 14px; padding: 20px; margin: 14px 0; box-shadow: 0 2px 10px rgba(80,60,20,.06); }
.ring-row { display: flex; align-items: center; gap: 20px; }
.ring { --p: 0; width: 96px; height: 96px; border-radius: 50%; flex: none;
  background: conic-gradient(var(--cinnabar) calc(var(--p) * 1%), var(--line) 0);
  display: grid; place-items: center; position: relative; }
.ring::after { content: ""; position: absolute; inset: 9px; background: var(--paper-2); border-radius: 50%; }
.ring b { position: relative; z-index: 1; font-size: 20px; }
.stats { display: flex; gap: 22px; flex-wrap: wrap; }
.stat b { display: block; font-size: 24px; color: var(--cinnabar); line-height: 1.2; }
.stat span { font-size: 13px; color: var(--ink-2); }
.btn { display: block; width: 100%; text-align: center; border: 0; border-radius: 12px; padding: 13px 16px; font: inherit; font-size: 17px; letter-spacing: .15em;
  background: var(--cinnabar); color: #fff; text-decoration: none; cursor: pointer; margin: 10px 0 0; }
.btn:hover { background: var(--cinnabar-d); }
.btn.ghost { background: transparent; color: var(--cinnabar); border: 1px solid var(--cinnabar); }
.btn.jade { background: var(--jade); }
.btn-row { display: flex; gap: 12px; } .btn-row .btn { flex: 1; }
.menu { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.menu a { display: block; text-decoration: none; color: var(--ink); background: var(--paper-2); border: 1px solid var(--line); border-radius: 12px; padding: 14px; text-align: center; letter-spacing: .15em; }
.menu a small { display: block; color: var(--ink-2); letter-spacing: 0; font-size: 12px; }
.tag { display: inline-block; font-size: 13px; color: var(--ink-2); border: 1px solid var(--line); border-radius: 999px; padding: 0 10px; }
.lesson-text { font-size: 26px; line-height: 1.7; letter-spacing: .08em; margin: 10px 0 14px; font-weight: 700; }
.lesson-body p, .lesson-body li { margin: .5em 0; }
.lesson-body ul, .lesson-body ol { padding-left: 1.3em; }
b.star { color: var(--cinnabar); }
details.notes { margin-top: 12px; border-top: 1px dashed var(--line); padding-top: 8px; color: var(--ink-2); font-size: 15px; }
details.notes summary { cursor: pointer; color: var(--gold); }
.src { color: var(--ink-2); font-size: 14px; margin-top: 10px; }
.dots { display: flex; gap: 6px; margin: 4px 0 12px; flex-wrap: wrap; }
.dots i { width: 10px; height: 10px; border-radius: 50%; background: var(--line); display: block; }
.dots i.done { background: var(--cinnabar); } .dots i.cur { outline: 2px solid var(--cinnabar); outline-offset: 2px; }
.opt { display: block; width: 100%; text-align: left; font: inherit; background: var(--paper-2); border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px; margin: 10px 0; cursor: pointer; color: var(--ink); }
.opt:hover { border-color: var(--cinnabar); }
.opt.right { border-color: var(--jade); background: #e8f1ec; }
.opt.wrong { border-color: var(--cinnabar); background: #f8e6e4; }
.prompt { font-size: 24px; letter-spacing: .08em; line-height: 1.8; margin: 8px 0; }
.stamp { position: fixed; right: 24px; top: 90px; width: 86px; height: 86px; border: 4px solid var(--cinnabar); color: var(--cinnabar); border-radius: 10px; display: grid; place-items: center; font-size: 34px; font-weight: 700; transform: rotate(-12deg) scale(0); opacity: 0; pointer-events: none; }
.stamp.show { animation: stamp .9s ease-out forwards; }
@keyframes stamp { 0% { transform: rotate(-12deg) scale(2.2); opacity: 0; } 30% { transform: rotate(-12deg) scale(1); opacity: .95; } 80% { opacity: .95; } 100% { transform: rotate(-12deg) scale(1); opacity: 0; } }
.list a { display: block; padding: 10px 2px; border-bottom: 1px solid var(--line); color: var(--ink); text-decoration: none; }
.list a small { color: var(--ink-2); }
.rank-row { display: flex; justify-content: space-between; padding: 10px 2px; border-bottom: 1px solid var(--line); }
.muted { color: var(--ink-2); font-size: 14px; }
.empty { text-align: center; color: var(--ink-2); padding: 30px 0; }
nav.tabs { position: fixed; left: 0; right: 0; bottom: 0; background: var(--paper-2); border-top: 1px solid var(--line); display: flex; justify-content: space-around; padding: 8px 0 calc(8px + env(safe-area-inset-bottom)); z-index: 5; }
nav.tabs a { color: var(--ink-2); text-decoration: none; font-size: 13px; text-align: center; letter-spacing: .1em; padding: 2px 10px; }
nav.tabs a.on { color: var(--cinnabar); font-weight: 700; }
.err { background: #f8e6e4; border: 1px solid var(--cinnabar); color: var(--cinnabar-d); border-radius: 12px; padding: 14px; margin: 14px 0; }
.btn-row.sticky { position: sticky; bottom: 66px; background: linear-gradient(transparent, var(--paper) 30%); padding-top: 14px; }