:root {
  --bg: #f6f7fb;
  --panel: #ffffff;
  --panel2: #eef0f6;
  --ink: #1c2333;
  --ink2: #5a6478;
  --ink3: #8b93a7;
  --line: #e4e7ef;
  --accent: #b03a2e;
  --accent2: #2e5cb0;
  --ok: #2e7d4f;
  --warn: #b0742e;
  --t1: #b03a2e;
  --t2: #2e5cb0;
  --t3: #6b6f7d;
  --shadow: 0 1px 3px rgba(20,28,50,.08), 0 4px 16px rgba(20,28,50,.05);
  --radius: 12px;
  --font: "PingFang SC","Microsoft YaHei",-apple-system,"Segoe UI",Roboto,sans-serif;
}
[data-theme="dark"] {
  --bg: #12151c;
  --panel: #1a1f2b;
  --panel2: #222838;
  --ink: #e7eaf2;
  --ink2: #a5adc0;
  --ink3: #6d7689;
  --line: #2c3344;
  --shadow: 0 1px 3px rgba(0,0,0,.4), 0 4px 16px rgba(0,0,0,.3);
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html,body { height: 100%; }
body {
  font-family: var(--font); background: var(--bg); color: var(--ink);
  font-size: 15px; line-height: 1.65; -webkit-font-smoothing: antialiased;
}
#app { display: flex; min-height: 100vh; }

/* ---------- Sidebar ---------- */
#sidebar {
  width: 236px; flex-shrink: 0; background: var(--panel);
  border-right: 1px solid var(--line); padding: 18px 14px;
  display: flex; flex-direction: column; position: sticky; top: 0; height: 100vh;
  overflow-y: auto; z-index: 30;
}
.brand { display: flex; gap: 10px; align-items: center; padding: 4px 6px 16px; }
.brand-mark {
  width: 40px; height: 40px; border-radius: 10px; background: var(--accent);
  color: #fff; font-size: 21px; font-weight: 700; display: flex; align-items: center; justify-content: center;
}
.brand-title { font-weight: 700; font-size: 15px; }
.brand-sub { font-size: 11px; color: var(--ink3); }
#nav { flex: 1; }
.nav-group { margin-bottom: 14px; }
.nav-label { font-size: 11px; color: var(--ink3); padding: 6px 10px 4px; letter-spacing: .5px; }
#nav a {
  display: flex; align-items: center; gap: 8px; padding: 8px 10px; margin: 1px 0;
  color: var(--ink2); text-decoration: none; border-radius: 8px; font-size: 14px;
}
#nav a:hover { background: var(--panel2); color: var(--ink); }
#nav a.active { background: var(--panel2); color: var(--ink); font-weight: 600; }
.tier-dot { width: 8px; height: 8px; border-radius: 50%; display: inline-block; flex-shrink: 0; }
.tier-dot.t1 { background: var(--t1); }
.tier-dot.t2 { background: var(--t2); }
.tier-dot.t3 { background: var(--t3); }
.side-foot { padding: 10px 6px 0; border-top: 1px solid var(--line); }
.countdown { font-size: 13px; color: var(--ink2); }
.countdown b { color: var(--accent); font-size: 18px; }

/* ---------- Main ---------- */
#main { flex: 1; min-width: 0; display: flex; flex-direction: column; }
#topbar {
  display: flex; align-items: center; gap: 12px; padding: 12px 22px;
  border-bottom: 1px solid var(--line); background: var(--panel);
  position: sticky; top: 0; z-index: 20;
}
#menu-btn { display: none; background: none; border: none; font-size: 20px; color: var(--ink2); cursor: pointer; }
.today-hint { font-size: 13px; color: var(--ink3); }
.top-right { margin-left: auto; }
#theme-btn { background: none; border: 1px solid var(--line); border-radius: 8px; padding: 5px 10px; cursor: pointer; font-size: 15px; color: var(--ink2); }

#view { padding: 26px 32px 60px; max-width: 1080px; width: 100%; margin: 0 auto; }

/* ---------- Cards / layout ---------- */
.card { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); padding: 20px 22px; margin-bottom: 18px; }
.page-head { margin-bottom: 18px; }
.page-head h1 { font-size: 24px; margin-bottom: 6px; }
.page-head p { color: var(--ink2); font-size: 14px; }
.h2 { font-size: 18px; margin: 8px 0 12px; display: flex; align-items: center; gap: 8px; }
.grid { display: grid; gap: 14px; }
.grid.c2 { grid-template-columns: 1fr 1fr; }
.grid.c3 { grid-template-columns: 1fr 1fr 1fr; }
@media (max-width: 900px) { .grid.c2, .grid.c3 { grid-template-columns: 1fr; } }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 6px; padding: 9px 16px;
  border-radius: 9px; border: 1px solid var(--line); background: var(--panel);
  color: var(--ink); cursor: pointer; font-size: 14px; font-family: var(--font);
  text-decoration: none;
}
.btn:hover { border-color: var(--ink3); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { opacity: .9; }
.btn.ghost { background: none; border-color: transparent; color: var(--ink2); }
.btn.sm { padding: 5px 10px; font-size: 13px; }

/* ---------- Stats / hero ---------- */
.hero { display: grid; grid-template-columns: repeat(auto-fit,minmax(180px,1fr)); gap: 14px; margin-bottom: 20px; }
.stat { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; box-shadow: var(--shadow); }
.stat .num { font-size: 26px; font-weight: 700; }
.stat .lbl { font-size: 12px; color: var(--ink3); margin-top: 2px; }
.stat.hot .num { color: var(--accent); }
.stat.blue .num { color: var(--accent2); }
.stat.green .num { color: var(--ok); }

/* ---------- Table ---------- */
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--line); }
th { color: var(--ink3); font-weight: 600; font-size: 12px; }
tbody tr:hover { background: var(--panel2); }
.tag { display: inline-block; padding: 1px 8px; border-radius: 20px; font-size: 11px; font-weight: 600; }
.tag.t1 { background: rgba(176,58,46,.12); color: var(--t1); }
.tag.t2 { background: rgba(46,92,176,.12); color: var(--t2); }
.tag.t3 { background: rgba(107,111,125,.14); color: var(--ink2); }
.tag.green { background: rgba(46,125,79,.12); color: var(--ok); }

/* ---------- Subject modules ---------- */
.module { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); margin-bottom: 16px; overflow: hidden; }
.module-head { display: flex; align-items: center; gap: 10px; padding: 14px 18px; cursor: pointer; }
.module-head:hover { background: var(--panel2); }
.module-head .chev { margin-left: auto; color: var(--ink3); transition: transform .15s; }
.module.open .module-head .chev { transform: rotate(90deg); }
.module-title { font-weight: 600; }
.module-meta { font-size: 12px; color: var(--ink3); display: flex; gap: 10px; align-items: center; }
.done-badge { color: var(--ok); font-weight: 600; }
.module-body { display: none; padding: 4px 18px 18px; }
.module.open .module-body { display: block; }
.section { margin-top: 16px; }
.section h4 { font-size: 15px; color: var(--accent2); margin-bottom: 8px; padding-bottom: 4px; border-bottom: 1px dashed var(--line); }
.point { margin-bottom: 14px; }
.point .t { font-weight: 600; }
.point .d { margin-top: 2px; color: var(--ink2); }
.point .ex { margin-top: 4px; font-size: 13px; background: var(--panel2); border-left: 3px solid var(--warn); padding: 6px 10px; border-radius: 0 8px 8px 0; color: var(--ink2); }

/* ---------- Cards quiz ---------- */
.card-quiz { max-width: 640px; margin: 0 auto; text-align: center; }
.qz-q { font-size: 18px; font-weight: 600; min-height: 70px; display: flex; align-items: center; justify-content: center; padding: 20px; }
.qz-ans { display: none; background: var(--panel2); border-radius: 10px; padding: 16px; text-align: left; margin: 10px 0 18px; color: var(--ink2); font-size: 14px; }
.qz-ans.show { display: block; }
.qz-controls { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }
.qz-count { color: var(--ink3); font-size: 13px; margin-bottom: 10px; }

/* ---------- QA / chat ---------- */
.search { width: 100%; padding: 12px 16px; border-radius: 10px; border: 1px solid var(--line); background: var(--panel); color: var(--ink); font-size: 15px; font-family: var(--font); }
.kb-item { margin-bottom: 10px; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
.kb-item .kb-q { padding: 12px 16px; cursor: pointer; font-weight: 600; font-size: 14px; display: flex; justify-content: space-between; align-items: center; }
.kb-item .kb-a { display: none; padding: 0 16px 14px; color: var(--ink2); font-size: 14px; }
.kb-item.open .kb-a { display: block; }
.chat-box { display: flex; flex-direction: column; gap: 12px; max-height: 480px; overflow-y: auto; padding: 6px 2px; }
.msg { max-width: 82%; padding: 10px 14px; border-radius: 12px; font-size: 14px; white-space: pre-wrap; word-break: break-word; }
.msg.user { align-self: flex-end; background: var(--accent); color: #fff; border-bottom-right-radius: 4px; }
.msg.bot { align-self: flex-start; background: var(--panel2); border-bottom-left-radius: 4px; color: var(--ink); }
.msg .meta { font-size: 11px; color: var(--ink3); margin-bottom: 4px; }
.chat-input-row { display: flex; gap: 8px; margin-top: 10px; }
.chat-input-row input { flex: 1; }
.msg-actions { display: flex; gap: 6px; padding: 2px 0 8px; align-self: flex-start; }
.msg-actions .btn { font-size: 12px; padding: 4px 9px; }
.chat-box { padding-bottom: 4px; }
textarea.search { resize: vertical; min-height: 70px; font-family: var(--font); }
#note-list .card { margin-bottom: 10px; }
.opt { display: flex; gap: 10px; align-items: flex-start; padding: 10px 12px; margin: 6px 0; border: 1px solid var(--line); border-radius: 9px; cursor: pointer; font-size: 14px; }
.opt:hover { background: var(--panel2); }
.opt-sel { border-color: var(--accent2); background: rgba(46,92,176,.06); }
.opt-ok { border-color: var(--ok); background: rgba(46,125,79,.08); color: var(--ok); font-weight: 600; }
.opt-no { border-color: var(--accent); background: rgba(176,58,46,.06); }
.opt-key { flex-shrink: 0; width: 22px; height: 22px; border-radius: 50%; border: 1px solid var(--ink3); display: flex; align-items: center; justify-content: center; font-size: 12px; font-weight: 600; color: var(--ink2); }

/* ---------- Misc ---------- */
.hint { font-size: 13px; color: var(--ink3); }
.progress-bar { height: 8px; background: var(--panel2); border-radius: 6px; overflow: hidden; margin-top: 8px; }
.progress-bar > i { display: block; height: 100%; background: var(--ok); border-radius: 6px; transition: width .3s; }
.progress-bar.acc > i { background: var(--accent); }
.kbd { background: var(--panel2); border: 1px solid var(--line); border-radius: 5px; padding: 0 6px; font-size: 12px; }
.day-card { border-left: 4px solid var(--accent); }
.day-card.done { border-left-color: var(--ok); opacity: .75; }
.day-card.done .module-title { text-decoration: line-through; color: var(--ink3); }
.day-num { font-size: 22px; font-weight: 700; color: var(--accent); min-width: 44px; }
.day-card.done .day-num { color: var(--ok); }
blockquote { border-left: 3px solid var(--accent2); background: var(--panel2); padding: 10px 14px; border-radius: 0 8px 8px 0; margin: 10px 0; color: var(--ink2); font-size: 14px; }
ul, ol { padding-left: 22px; }
li { margin: 3px 0; }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  #sidebar { position: fixed; left: 0; top: 0; transform: translateX(-100%); transition: transform .2s; height: 100vh; }
  #sidebar.open { transform: translateX(0); box-shadow: var(--shadow); }
  #menu-btn { display: block; }
  #view { padding: 18px 14px 60px; }
}

/* ---------- Scrollbar ---------- */
::-webkit-scrollbar { width: 9px; height: 9px; }
::-webkit-scrollbar-thumb { background: var(--ink3); border-radius: 6px; opacity: .5; }
::-webkit-scrollbar-track { background: transparent; }