:root{
  --bg:#f4f6f8;
  --card:#ffffff;
  --text:#1a1a1a;
  --sub:#5a6472;
  --border:#e0e5ea;
  --header-bg:#1A5276;
  --accent:#2471A3;
  --accent-light:#D6EAF8;
  --table-head:#4A5568;
  --table-even:#EBF5FB;
  --good:#2e8b57;
  --bad:#c0392b;
  --shadow:0 2px 8px rgba(0,0,0,.08);
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  font-family:"Hiragino Sans","Noto Sans JP","Yu Gothic",sans-serif;
  background:var(--bg);
  color:var(--text);
  line-height:1.7;
  padding-bottom:70px;
}
header.appbar{
  position:sticky;top:0;z-index:20;
  background:var(--header-bg);
  color:#fff;
  padding:12px 16px;
  display:flex;align-items:center;gap:10px;
  box-shadow:var(--shadow);
}
header.appbar .back{
  background:none;border:none;color:#fff;font-size:20px;cursor:pointer;
  padding:4px 8px;line-height:1;
}
header.appbar h1{
  font-size:16px;margin:0;font-weight:700;flex:1;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
main{
  max-width:720px;margin:0 auto;padding:16px;
}
/* ---- Dashboard ---- */
.hero{
  background:linear-gradient(135deg,#1A5276,#2471A3);
  color:#fff;border-radius:16px;padding:20px;margin-bottom:18px;
  box-shadow:var(--shadow);
}
.hero h2{margin:0 0 6px;font-size:20px}
.hero p{margin:0;font-size:13px;opacity:.9}
.progress-bar-wrap{
  background:rgba(255,255,255,.25);border-radius:8px;height:10px;margin-top:12px;overflow:hidden;
}
.progress-bar-fill{
  background:#fff;height:100%;border-radius:8px;transition:width .3s;
}
.progress-label{font-size:12px;margin-top:6px;opacity:.9}

.section-label{
  font-size:13px;font-weight:700;color:var(--sub);margin:22px 0 10px;
  text-transform:uppercase;letter-spacing:.04em;
}
.chapter-card{
  display:flex;align-items:center;gap:14px;
  background:var(--card);border-radius:12px;padding:14px 16px;margin-bottom:10px;
  box-shadow:var(--shadow);cursor:pointer;border:1px solid var(--border);
  text-decoration:none;color:inherit;
}
.chapter-card:active{transform:scale(.99)}
.chapter-num{
  width:40px;height:40px;border-radius:50%;flex:none;
  display:flex;align-items:center;justify-content:center;
  color:#fff;font-weight:700;font-size:15px;
}
.chapter-info{flex:1;min-width:0}
.chapter-info h3{margin:0 0 3px;font-size:15px}
.chapter-info .meta{font-size:12px;color:var(--sub)}
.chapter-status{font-size:11px;font-weight:700;padding:3px 9px;border-radius:20px;flex:none}
.chapter-status.done{background:#e3f7ea;color:var(--good)}
.chapter-status.progress{background:#fff4de;color:#b8860b}
.chapter-status.todo{background:#eef0f2;color:var(--sub)}

/* ---- Chapter TOC page ---- */
.chapter-hero{
  border-radius:14px;padding:18px;margin-bottom:16px;color:#fff;
}
.chapter-hero h2{margin:0 0 4px;font-size:19px}
.chapter-hero .sub{font-size:13px;opacity:.9}
.section-list{list-style:none;margin:0;padding:0}
.section-list li{
  background:var(--card);border:1px solid var(--border);border-radius:10px;
  padding:12px 14px;margin-bottom:8px;display:flex;align-items:center;gap:10px;
  cursor:pointer;
}
.section-list li .idx{
  width:26px;height:26px;border-radius:50%;background:var(--accent-light);color:var(--accent);
  display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:700;flex:none;
}
.section-list li .stitle{flex:1;font-size:14px}
.section-list li .chk{color:var(--good);font-size:16px;flex:none}
.quiz-cta{
  margin-top:18px;background:var(--card);border:2px dashed var(--accent);border-radius:12px;
  padding:16px;text-align:center;
}
.quiz-cta button{margin-top:8px}

/* ---- Lesson page ---- */
.lesson-block h3{
  color:var(--accent);font-size:16px;margin:22px 0 8px;border-left:4px solid var(--accent);padding-left:8px;
}
.lesson-block p{font-size:14.5px;margin:8px 0}
.lesson-block ul,.lesson-block ol{font-size:14.5px;padding-left:22px}
.lesson-block li{margin:4px 0}
mark{background:#fff2a8;padding:0 2px;border-radius:2px}
.note{
  background:var(--accent-light);border-radius:10px;padding:12px 14px;margin:12px 0;font-size:13.5px;color:#154360;
}
.note b{color:var(--header-bg)}
.formula{
  background:#2c3e50;color:#fff;border-radius:10px;padding:14px;margin:12px 0;
  font-size:16px;text-align:center;font-weight:700;letter-spacing:.02em;
}
.table-wrap{overflow-x:auto;margin:12px 0;border-radius:10px;border:1px solid var(--border)}
table{width:100%;border-collapse:collapse;font-size:13px;min-width:420px}
th{background:var(--table-head);color:#fff;padding:8px 10px;text-align:left;white-space:nowrap}
td{padding:8px 10px;border-bottom:1px solid var(--border)}
tr:nth-child(even) td{background:var(--table-even)}
.diagram{
  background:#fff;border:1px solid var(--border);border-radius:10px;padding:10px;margin:12px 0;text-align:center;
}
.diagram svg{max-width:100%;height:auto}
.diagram .cap{font-size:12px;color:var(--sub);margin-top:6px}
.symbol-grid{
  display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:8px;margin:12px 0;
}
.symbol-card{
  background:#fff;border:1px solid var(--border);border-radius:10px;padding:10px;text-align:center;
}
.symbol-card svg{width:48px;height:48px}
.symbol-card .name{font-size:11.5px;margin-top:4px;color:var(--text)}

.lesson-nav{
  display:flex;justify-content:space-between;gap:10px;margin-top:24px;
}
button, .btn{
  font-family:inherit;font-size:14px;font-weight:700;border-radius:10px;border:none;
  padding:11px 18px;cursor:pointer;background:var(--accent);color:#fff;
}
button.secondary{background:#fff;color:var(--accent);border:1px solid var(--accent)}
button:disabled{opacity:.4;cursor:default}
button.block{width:100%}

/* ---- Quiz ---- */
.quiz-progress{font-size:12px;color:var(--sub);margin-bottom:10px}
.quiz-card{
  background:var(--card);border-radius:14px;padding:18px;box-shadow:var(--shadow);
}
.quiz-q{font-size:15.5px;font-weight:700;margin-bottom:14px;white-space:pre-wrap}
.quiz-choices{list-style:none;margin:0;padding:0}
.quiz-choices li{
  border:1.5px solid var(--border);border-radius:10px;padding:12px 14px;margin-bottom:9px;
  font-size:14px;cursor:pointer;
}
.quiz-choices li:active{background:#f5f7f9}
.quiz-choices li.selected{border-color:var(--accent);background:var(--accent-light)}
.quiz-choices li.correct{border-color:var(--good);background:#e3f7ea;font-weight:700}
.quiz-choices li.wrong{border-color:var(--bad);background:#fdecea;font-weight:700}
.quiz-explain{
  font-size:13.5px;background:#f8f9fb;border-radius:10px;padding:12px;margin-top:12px;color:var(--sub);display:none;
}
.quiz-explain.show{display:block}
.quiz-result{
  text-align:center;padding:26px 16px;
}
.quiz-result .score{font-size:44px;font-weight:800;color:var(--accent);margin:8px 0}
.quiz-result .msg{font-size:14px;color:var(--sub);margin-bottom:18px}

.badge-row{display:flex;gap:8px;flex-wrap:wrap;margin-top:10px}
.tag{font-size:11px;background:var(--accent-light);color:var(--accent);padding:3px 9px;border-radius:20px}

footer.tabbar{
  position:fixed;bottom:0;left:0;right:0;background:#fff;border-top:1px solid var(--border);
  display:flex;z-index:20;
}
footer.tabbar a{
  flex:1;text-align:center;padding:9px 0 7px;color:var(--sub);text-decoration:none;font-size:11px;
}
footer.tabbar a.active{color:var(--accent);font-weight:700}
footer.tabbar .ic{font-size:19px;display:block}

@media (max-width:400px){
  .hero h2{font-size:18px}
}